Severe Asthma Phenotypes and Endotypes

Severe asthma is not a single disease. It is a collection of distinct biological subtypes - called phenotypes (what you observe) and endotypes (the underlying mechanism) - each requiring a different treatment strategy. Identifying your phenotype is the most important step your specialist will take before recommending a biologic or advanced therapy.

Allergic Asthma (T2-High, IgE-Driven)

Allergic asthma is the most common severe asthma phenotype, typically beginning in childhood or adolescence. It is defined by sensitization to perennial aeroallergens. Key biomarkers: elevated total serum IgE (often 100-700 IU/mL), positive skin prick testing or allergen-specific IgE, blood eosinophils often elevated, FeNO often elevated (greater than 25 ppb). Primary biologic: omalizumab (Xolair).

Allergen immunotherapy (AIT): For eligible patients (FEV1 >=70% predicted, well-controlled baseline asthma), AIT can modify the underlying disease. Subcutaneous immunotherapy (SCIT) involves weekly injections for 6-12 months followed by monthly injections for 3-5 years. Sublingual immunotherapy (SLIT) tablets are available for dust mite (Odactra) and grass pollen (Grastek, Oralair).

Eosinophilic Asthma (T2-High, IL-5-Driven)

Eosinophilic asthma is characterized by excess eosinophils. It often has a late-onset pattern (adult diagnosis, frequently age 30-50), may occur without clear allergen sensitization, and is strongly associated with nasal polyposis (40-50% of patients) and aspirin sensitivity (10-20%). Key biomarkers: blood eosinophils >=300 cells/microL (>=500 is strongest predictor); sputum eosinophils >=3%; FeNO greater than 25 ppb. Biologic options: mepolizumab, reslizumab, benralizumab, and dupilumab.

AERD - Aspirin-Exacerbated Respiratory Disease (Samter's Triad)

AERD affects approximately 10% of adults with severe asthma and is defined by the co-occurrence of: (1) asthma, (2) chronic rhinosinusitis with nasal polyps, and (3) hypersensitivity to aspirin and other COX-1 inhibiting NSAIDs. Mechanism: COX-1 inhibition blocks prostaglandin E2 production; arachidonic acid is shunted into the 5-lipoxygenase pathway, producing a surge of cysteinyl leukotrienes causing intense bronchoconstriction within 30-120 minutes of NSAID ingestion.

Aspirin Desensitization: Performed at experienced centers (Brigham and Women's Hospital, UCSF Nasal and Sinus Center, Cleveland Clinic), starting with very low aspirin dose (20-40 mg) and incrementally increasing every 90-180 minutes under direct medical supervision. After reaching a full dose (325-650 mg) without reaction, patients maintain daily aspirin therapy. Long-term daily aspirin maintenance reduces nasal polyp regrowth, decreases the need for sinus surgeries, and improves asthma control. Patients with AERD must strictly avoid all COX-1 inhibitors - only celecoxib (selective COX-2 inhibitor) and acetaminophen at standard doses are safe alternatives.

ABPA - Allergic Bronchopulmonary Aspergillosis

ABPA is a hypersensitivity disorder caused by colonization of the airways with Aspergillus fumigatus. It occurs primarily in patients with asthma (estimated 2-3%) and cystic fibrosis. Left untreated, ABPA leads to progressive central bronchiectasis and irreversible lung damage. Diagnosis requires: (1) asthma or CF, (2) positive immediate skin reactivity to Aspergillus or elevated Aspergillus-specific IgE, (3) total serum IgE greater than 1,000 IU/mL, plus additional criteria. Treatment: oral prednisone 0.5 mg/kg/day for 2 weeks, then taper over 3-6 months based on total IgE levels; plus oral itraconazole 200 mg twice daily for 16 weeks as a steroid-sparing agent.

T2-Low Phenotypes: Neutrophilic, Paucigranulocytic, and Obesity-Related

Neutrophilic asthma is associated with occupational exposures, active or ex-smoking, and recurrent infections. Azithromycin 500 mg three times per week (Monday/Wednesday/Friday) demonstrated a 41% reduction in severe exacerbations in the AMAZES trial through anti-inflammatory mechanisms. Long-term macrolide use requires monitoring for hearing loss and QTc prolongation.

Obesity-related asthma is predominantly T2-low and non-eosinophilic. Standard biologics targeting IL-5/IL-4/IgE are frequently ineffective. Weight loss of as little as 10 kg can produce clinically meaningful improvement in FEV1 (approximately 150-200 mL), ACQ score, and exacerbation rate. Bariatric surgery 2-year follow-up data show significant asthma improvement in a majority of patients.

Questions to Ask Your Specialist About Phenotyping

Which phenotype do I have - T2-high or T2-low? What tests confirmed this?
Do I have AERD? Should I avoid all NSAIDs indefinitely, and am I a candidate for aspirin desensitization?
Could I have ABPA? What is my total IgE, and has Aspergillus hypersensitivity been tested?
Is my exercise limitation due to asthma, VCD, deconditioning, or some combination?
How does my weight affect my asthma, and what specific support can I get for weight management?
Am I eligible for allergen immunotherapy, and which allergens should be targeted?

Step-Up Therapy and the GINA 2026 Treatment Algorithm

The GINA 2026 Paradigm Shift: GINA 2026 fundamentally changed first-line asthma therapy. As-needed SABA alone is no longer recommended as reliever therapy at any step. Every patient with asthma - even those with the mildest, most intermittent symptoms - should receive an inhaled corticosteroid component with every reliever dose.

GINA Step 1 - Mild Intermittent Asthma

First choice: As-needed low-dose ICS-formoterol (AIR strategy). NOT recommended: As-needed SABA alone - this is no longer a recommended strategy under GINA 2026 for any step.

GINA Step 2 - Mild Persistent Asthma

First choice: Low-dose ICS maintenance plus as-needed low-dose ICS-formoterol as reliever. Alternative: As-needed low-dose ICS-formoterol only (SMART/AIR - no separate daily maintenance inhaler). Leukotriene receptor antagonist (LTRA - montelukast): An alternative to ICS for patients who cannot or will not use inhaled therapy. FDA-mandated Boxed Warning for neuropsychiatric events (depression, suicidal ideation, aggression) - reserve for patients in whom ICS-based therapy is not appropriate.

GINA Step 3 - Moderate Persistent Asthma

First choice: Low-dose ICS-formoterol maintenance plus as-needed ICS-formoterol reliever (SMART). In SMART, the patient uses the same ICS-formoterol inhaler for scheduled twice-daily maintenance AND as-needed relief - up to a protocol-specified maximum of 8 puffs per day in some formulations.

Alternative: Low-dose or medium-dose ICS-LABA maintenance (budesonide-formoterol, fluticasone-salmeterol [Advair], or fluticasone-vilanterol [Breo Ellipta]) plus as-needed SABA reliever.

GINA Step 4 - Severe Persistent Asthma (High-Dose ICS-LABA)

First choice: Medium-to-high-dose ICS-LABA maintenance plus as-needed ICS-formoterol reliever. High-dose ICS is defined as: fluticasone propionate greater than 500 mcg/day, budesonide greater than 800 mcg/day, mometasone greater than 400 mcg/day.

Add-on tiotropium (Spiriva Respimat): Tiotropium 2.5 mcg (2 puffs) once daily via Respimat inhaler may be added as a third controller at Step 4 or 5. FDA-approved as add-on maintenance for asthma down to age 6 (since 2017). Provides modest FEV1 improvement (approximately +110 mL above ICS-LABA baseline). Particularly useful in patients with prominent fixed airflow obstruction. Side effects include dry mouth, urinary retention, constipation, glaucoma exacerbation.

Refer to severe asthma specialist: Any patient requiring Step 4 therapy or higher, or any patient with frequent exacerbations, OCS use, or emergency department visits, should be referred to a specialist in severe asthma.

GINA Step 5 - Very Severe / Refractory Asthma (Add-On Therapies)

Biologic therapy: The selection algorithm based on biomarker profile applies here. Biologics are the preferred Step 5 add-on for T2-high disease and are strongly preferred over chronic OCS due to superior risk-benefit profiles.

Azithromycin 500 mg three times weekly: The AMAZES trial demonstrated 41% reduction in exacerbation rate in adults with uncontrolled persistent asthma - notably with the greatest absolute benefit in patients without sputum eosinophilia (T2-low asthma). Important: baseline ECG recommended (QTc prolongation risk); annual audiogram advisable for long-term use.

Low-dose oral corticosteroids (maintenance OCS): Last-resort add-on when biologic therapies are unavailable, contraindicated, or have failed. The cumulative toxicity of chronic OCS is substantial: adrenal suppression, osteoporosis, hyperglycemia, Cushingoid features, hypertension, cataracts, growth suppression in children, increased infection risk. Prescribe calcium 1,000-1,200 mg and vitamin D 800-2,000 IU daily and obtain DEXA scan for all patients on maintenance OCS.

SMART Therapy - Using One Inhaler for Both Maintenance and Relief

SMART is a prescribing strategy in which the same low-dose ICS-formoterol inhaler is used for scheduled maintenance doses (typically twice daily) and for as-needed symptom relief. The patient does not use a separate SABA reliever. This strategy is superior to conventional fixed-dose ICS-LABA plus SABA reliever for exacerbation prevention in multiple large trials. FDA-approved in 2019 for budesonide-formoterol (Symbicort) in adults and adolescents. Key practical points: maximum relief doses per day should be specified in the written asthma action plan (typically no more than 8 total puffs/day); patients must clearly understand that all doses - both maintenance and relief - come from the same device.

Bronchial Thermoplasty - The Non-Biologic Procedural Option

Bronchial thermoplasty (BT) is a bronchoscopic procedure in which radiofrequency energy is delivered to the airway wall to ablate hypertrophic airway smooth muscle. FDA-approved in 2010 (AIR2 trial, NCT00231114) as an add-on treatment for severe persistent asthma in adults 18 years and older whose asthma is not well controlled with ICS and LABA. The procedure is performed over three bronchoscopic sessions spaced three weeks apart. Patient selection for BT is highly selective: generally considered after failure or contraindication of biologic therapy, particularly in T2-low patients who lack biologic options. Risks include increased exacerbations in the months immediately following the procedure (expected procedural inflammatory response), rare pneumothorax, and hemoptysis. Long-term 5-year follow-up data from the AIR2 trial demonstrate sustained reduction in exacerbations, hospitalizations, and emergency visits.

Comorbidity Management

Uncontrolled comorbidities are a major driver of apparent biologic non-response. Every severe asthma patient should be systematically evaluated for:

Allergic rhinitis and CRS: Intranasal corticosteroid spray (fluticasone, mometasone, triamcinolone) plus antihistamine as needed. For CRSwNP, dupilumab is approved and addresses both nasal and asthma disease simultaneously.
GERD: A trial of PPI therapy for 8-12 weeks is reasonable in patients with symptomatic reflux and poorly controlled asthma.
Obstructive sleep apnea (OSA): Screen with STOP-BANG questionnaire; refer for polysomnography if positive. CPAP therapy can improve asthma symptoms and reduce OCS requirements.
Obesity: 5-10% weight loss improves FEV1, symptoms, and exacerbation frequency. Refer to obesity medicine specialist and nutritional counseling.
Vocal cord dysfunction (VCD): Speech therapy (laryngeal control exercises) is the cornerstone treatment. Heliox for acute attacks. VCD does not respond to bronchodilators or biologic therapy.
Anxiety and depression: Integrate mental health screening (PHQ-9, GAD-7) into severe asthma care. Cognitive-behavioral therapy and SSRIs are appropriate. Avoid montelukast in patients with active depression or anxiety given the FDA Boxed Warning.

Adherence and Inhaler Technique

Inhaler technique: Demonstrate proper technique at every visit. Common MDI errors: failure to exhale before inhalation, inhaling too rapidly, not holding breath for 10 seconds after actuation, not shaking, not using spacer. DPI errors: not inhaling forcefully enough, exhaling into the device.
Spacer devices: Valved holding chambers substantially improve MDI drug delivery to the lungs and reduce oropharyngeal deposition (and associated thrush). Recommend for all patients using MDIs, especially children.
Smart inhalers: Propeller Health sensor (FDA-cleared) and Adherium Smartinhaler track time and date of each inhaler actuation and can send reminders via smartphone app.
Written asthma action plan: Every severe asthma patient should have a written action plan specifying green zone (well-controlled - continue maintenance), yellow zone (worsening - step up reliever, possibly add short OCS burst), and red zone (severe worsening - use rescue medications, call provider, go to ED). Action plans reduce exacerbation-related hospitalization and emergency visits by 25-40%.

Monitoring Severe Asthma - What to Track at Every Visit

ACQ-7 or ACT score: ACQ-7 score greater than 1.5 indicates uncontrolled asthma; ACT score 19 or below indicates not well-controlled. Use consistently across visits to track trajectory.
Exacerbation rate: Count of courses of OCS or ED visits or hospitalizations for asthma in past 12 months. Target: fewer than 2 per year.
Spirometry: Pre- and post-bronchodilator FEV1 and FVC. Track FEV1 trajectory - progressive decline suggests inadequate control or airway remodeling.
FeNO: At baseline before biologic initiation and at follow-up visits. Persistently elevated FeNO on biologic therapy may indicate non-adherence, ongoing allergen exposure, or OCS withdrawal unmasking inflammation.
Blood eosinophil count: At every biologic visit. On benralizumab, count should fall to near zero. Persistent high counts on IL-5 therapy may indicate inadequate drug exposure.

Questions to Ask Your Doctor About Step-Up Therapy

Should I still keep my rescue inhaler, or does my ICS-formoterol inhaler replace it?
How many times can I use my reliever inhaler in a day before I should call you?
Can you check my inhaler technique at this visit?
Do I need a spacer device with my inhaler?
Should I be using one inhaler or two - am I on SMART therapy?
What should my written asthma action plan say?
Is my asthma at the point where a biologic is appropriate?
Should I be taking prednisone every day, or can we taper it if I start a biologic?
Are there side effects from my long-term steroid use I should be screened for (bone density, blood sugar, cataracts)?
Is a referral to a severe asthma center appropriate at this point?

Caregiver Daily Management Note: If you support a family member with severe asthma, the most important things you can do are: (1) learn to recognize early warning signs of worsening (increased reliever use, nighttime awakenings, declining peak flow); (2) know the written action plan and what step to take at each zone; (3) know where the nearest emergency department is and when to call 911 (inability to speak, severe breathlessness, no improvement after 4-6 puffs of reliever in 20 minutes); (4) help manage the home environment; (5) support medication adherence. Connect with the Asthma and Allergy Foundation of America (aafa.org, 1-800-7-ASTHMA) for family support resources.

Biologic Therapies for Severe Asthma

Who Should Consider a Biologic? Biologics are indicated at GINA Step 5 - severe asthma that remains uncontrolled despite high-dose ICS-LABA therapy. Before starting any biologic, confirm: (1) diagnosis is correct (rule out VCD, ABPA, cardiac wheeze), (2) inhaler technique is optimal, (3) adherence is verified, (4) comorbidities are treated. A severe asthma specialist evaluation is strongly recommended before initiation.

1. Omalizumab (Xolair) - Anti-IgE

Manufacturer: Genentech / Novartis. FDA Approval: June 2003 for moderate-to-severe allergic asthma in patients aged 6 years and older.

Mechanism: Binds selectively to free circulating IgE at the Fc-epsilon-3 domain, preventing IgE from binding to high-affinity IgE receptors (FcRI) on mast cells and basophils. Over 12-16 weeks, FcRI receptor expression on mast cells and basophils is substantially downregulated.

Patient Eligibility: Moderate-to-severe persistent allergic asthma inadequately controlled on ICS; baseline total serum IgE between 30 and 700 IU/mL; documented sensitization to at least one perennial aeroallergen; age 6 years and older.

Dosing: Dose is determined by a weight-IgE dosing nomogram ranging from 75 mg to 375 mg by subcutaneous injection every 2 or 4 weeks. The first injection must be administered in a healthcare setting with a 30-minute observation period due to anaphylaxis risk (estimated 2-3 per 1,000 patients). Patients must carry an epinephrine auto-injector at all times.

Efficacy: EXTRA trial (NCT00314574): 25-50% reduction in exacerbation rates. Assess response at 16 weeks and discontinue if no response is seen.

Also approved: Chronic idiopathic urticaria (adults and adolescents >=12 years). Allergic rhinitis symptoms often improve as well.

Patient Assistance: Genentech Access Solutions - 1-888-249-4918. The STELLR program provides dosing support, injection training, and financial assistance navigation.

2. Mepolizumab (Nucala) - Anti-IL-5

Manufacturer: GlaxoSmithKline (GSK). FDA Approval: November 2015 for severe eosinophilic asthma; expanded to age 6 and older in 2019.

Mechanism: Fully humanized IgG1 monoclonal antibody that binds to interleukin-5 (IL-5), the primary cytokine responsible for eosinophil production, maturation, survival, and tissue trafficking. Blood eosinophil counts typically fall by 80-90% within 4 weeks of the first dose.

Patient Eligibility: Severe eosinophilic asthma inadequately controlled on high-dose ICS plus additional controller; blood eosinophil count >=150 cells/microL at initiation; age 6 years and older.

Dosing: Adults and adolescents >=12 years: 100 mg SC every 4 weeks. Children 6-11 years weighing less than 40 kg: 40 mg SC q4wks. Weighing >=40 kg: 100 mg SC q4wks. Self-injection at home possible using the autoinjector (SHL Molly) or prefilled syringe after the first dose in clinic.

Efficacy: MENSA trial (NCT01691521): 53% reduction in clinically significant exacerbations. SIRIUS trial (NCT01691508): 50% reduction in OCS dose; 23% of mepolizumab patients achieved complete OCS discontinuation.

Additional Approved Indications: Eosinophilic granulomatosis with polyangiitis (EGPA), hypereosinophilic syndrome (HES), and chronic rhinosinusitis with nasal polyps (CRSwNP).

Patient Assistance: GSK myNUCALA program - 1-888-825-5249.

3. Reslizumab (Cinqair) - Anti-IL-5 (Intravenous)

Manufacturer: Teva Pharmaceuticals. FDA Approval: March 2016 for severe eosinophilic asthma in adults 18 years and older.

Mechanism: Humanized IgG4kappa monoclonal antibody that binds IL-5 with very high affinity. IV route allows weight-based dosing.

Patient Eligibility: Severe eosinophilic asthma inadequately controlled on ICS; blood eosinophil count >=400 cells/microL; adults 18 years and older only.

Dosing: 3 mg/kg intravenous infusion every 4 weeks. Requires infusion center visit with approximately 20-50 minutes infusion time plus post-infusion observation.

Safety - Boxed Warning: Reslizumab carries an FDA Boxed Warning for anaphylaxis (occurred in 0.3% of patients across clinical trials). Epinephrine and resuscitation equipment must be available at every infusion. Healthcare providers must be trained to recognize and manage anaphylaxis.

Efficacy: Phase 3 trials: 50-59% reduction in exacerbation rates in patients with blood eosinophils >=400. FEV1 improvement of approximately +0.12 L.

Patient Assistance: Teva patient support - 1-888-CINQAIR (1-888-246-7247).

4. Benralizumab (Fasenra) - Anti-IL-5Ralpha

Manufacturer: AstraZeneca. FDA Approval: November 2017 for severe eosinophilic asthma in patients 12 years and older.

Mechanism: Humanized, afucosylated IgG1kappa monoclonal antibody targeting the alpha subunit of the IL-5 receptor (IL-5Ralpha) on eosinophils and basophils. Triggers antibody-dependent cellular cytotoxicity (ADCC) via NK cells, rapidly depleting eosinophils from blood and tissue - blood eosinophil counts typically fall to near zero within 2 weeks of the first dose.

Patient Eligibility: Severe eosinophilic asthma inadequately controlled on high-dose ICS-LABA; blood eosinophil count >=300 cells/microL; age 12 years and older.

Dosing - The 8-Week Maintenance Advantage: 30 mg SC every 4 weeks for the first 3 doses (loading phase at weeks 0, 4, and 8), then 30 mg SC every 8 weeks thereafter. This every-8-week maintenance schedule - 6 injections per year after the loading phase - is unique among asthma biologics. Self-administration at home after the first dose in a clinical setting.

Efficacy: SIROCCO (NCT01928771) and CALIMA (NCT01914757): 51-59% reductions in exacerbation rates. ZONDA trial (NCT02075255): 75% of benralizumab patients reduced OCS dose by >=50%, with 52% achieving complete OCS elimination.

Patient Assistance: AstraZeneca Fasenra Patient Assistance Program - 1-844-203-7221. The FASENRA STAR program provides adherence support.

5. Dupilumab (Dupixent) - Anti-IL-4Ralpha (Dual IL-4/IL-13 Blockade)

Manufacturer: Regeneron Pharmaceuticals and Sanofi. FDA Approval: October 2018 for moderate-to-severe asthma in adults and adolescents 12 years and older; expanded to children 6-11 years in 2021.

Mechanism: Fully human IgG4 monoclonal antibody that binds the IL-4 receptor alpha subunit (IL-4Ralpha), which is shared between the Type I IL-4 receptor (active on T cells and innate lymphoid cells) and the Type II IL-4 receptor (active on non-hematopoietic cells including airway epithelium). By blocking the shared IL-4Ralpha subunit, dupilumab simultaneously inhibits both IL-4 and IL-13 signaling. Note: blood eosinophil counts paradoxically rise transiently after starting dupilumab (reduced tissue homing disperses tissue eosinophils back to blood) before normalizing - this is expected and should not prompt discontinuation.

Patient Eligibility: Moderate-to-severe persistent asthma inadequately controlled on medium-to-high-dose ICS plus LABA; blood eosinophil count >=150 cells/microL OR FeNO >=25 ppb (either biomarker qualifies); age 6 years and older. Patients with eos >=300 or FeNO >=50 show the largest treatment benefits.

Dosing: Adults and adolescents >=12 years: 200 mg or 300 mg SC every 2 weeks (300 mg preferred for OCS-dependent asthma or co-existing moderate-to-severe atopic dermatitis). Children 6-11 years: weight-based (100 mg q2wks if less than 30 kg; 200 mg q2wks if >=30 kg). All doses self-injected at home after training.

Efficacy: QUEST trial (NCT02414854): 65-70% exacerbation reduction in patients with eos >=300 cells/microL or FeNO >=25 ppb. FEV1 improvement averaged +0.32 L in the T2-high subgroup. VENTURE trial: 70% reduction in OCS dose; 48% able to completely discontinue OCS.

Multi-Disease Approval - A Unique Advantage: Dupilumab is the most broadly approved biologic across T2-inflammatory diseases: atopic dermatitis (>=6 months of age), CRSwNP, eosinophilic esophagitis (EoE, >=12 years), prurigo nodularis, chronic spontaneous urticaria (CSU, 2024), and asthma (>=6 years). Patients with severe asthma and co-existing atopic dermatitis, nasal polyps, or EoE can treat all conditions simultaneously.

Side Effects: Injection site reactions common and typically mild. Conjunctivitis occurs in 10-20% of patients receiving dupilumab for asthma plus atopic dermatitis.

Patient Assistance: DUPIXENT MyWay - 1-844-DUPIXENT (1-844-387-4936). Extensive resources at dupixent.com/asthma.

6. Tezepelumab (Tezspire) - Anti-TSLP (The Upstream Alarmin Blocker)

Manufacturer: AstraZeneca and Amgen. FDA Approval: December 2021 for severe asthma in patients 12 years and older.

Mechanism: First-in-class human IgG2lambda monoclonal antibody targeting thymic stromal lymphopoietin (TSLP) - an epithelial-derived alarmin cytokine released in response to barrier insults including allergens, environmental pollutants, viruses, cigarette smoke, and mechanical stress. TSLP acts upstream of all other targeted cytokines and activates multiple innate and adaptive immune pathways.

The Critical Distinction - No Biomarker Threshold: Tezepelumab is the only FDA-approved severe asthma biologic that does not require a minimum blood eosinophil count or FeNO level for prescribing. This makes it uniquely relevant for T2-low severe asthma patients.

Patient Eligibility: Severe asthma inadequately controlled on high-dose ICS-LABA; age 12 years and older; no minimum biomarker threshold required. Particularly valuable for T2-low patients (eos less than 150, FeNO less than 25); patients with multiple asthma phenotypes; patients who failed or were ineligible for other biologics.

Dosing: 210 mg SC every 4 weeks. Fixed dose - no weight-based adjustment. Prefilled syringe or autoinjector.

Efficacy: NAVIGATOR trial (NCT03347279) - enrolled 1,061 patients: 56% reduction in annualized exacerbation rate overall, with significant reductions across all biomarker subgroups: Eos >=300 = 70% reduction; Eos 150-299 = 57% reduction; Eos less than 150 = 41% reduction; FeNO less than 25 = 37% reduction. SOURCE trial (NCT03406078): did NOT meet its primary oral-steroid-reduction endpoint in the overall population (numerical 75% vs 66% on placebo, not statistically significant; benefit seen only post-hoc in T2-high patients). DESTINATION trial (NCT03706079): 2-year safety and durability extension confirming sustained exacerbation reduction (a long-term safety study, not an oral-steroid-elimination trial).

Patient Assistance: Tezspire patient access support - 1-844-TEZSPIRE. Available through specialty pharmacy only.

7. Depemokimab (Exdensur) - Anti-IL-5 (Twice-Yearly)

Manufacturer: GlaxoSmithKline (GSK). FDA Approval: December 16, 2025 for add-on maintenance treatment of severe asthma with an eosinophilic phenotype in patients 12 years and older.

Mechanism: An ultra-long-acting humanized monoclonal antibody against IL-5 (the same cytokine target as mepolizumab) engineered for high potency and a long half-life, enabling dosing just twice a year.

Patient Eligibility: Severe asthma with an eosinophilic phenotype, inadequately controlled on high-dose ICS plus an additional controller; age 12 years and older.

Dosing - The Twice-Yearly Advantage: 100 mg SC at week 0 and week 26, then every 26 weeks (twice yearly) - the longest dosing interval of any asthma biologic, just two injections per year.

Efficacy: The SWIFT-1 (NCT04719832) and SWIFT-2 (NCT04718103) trials showed 58% and 48% reductions in annualized exacerbations versus placebo. Important caveat: in the NIMBLE switch trial, depemokimab did NOT demonstrate non-inferiority to existing anti-IL-5 therapy (mepolizumab/benralizumab) - so it is not established as equivalent to those agents, but offers a convenient twice-yearly option for eligible eosinophilic patients.

Patient Assistance: GSK patient support (verify current program details with your specialist or GSK).

Biologic Selection Guide - Matching Patient to Drug

Biomarker-Based Decision Algorithm (Simplified):

Allergic asthma + IgE 30-700 + perennial sensitization: Omalizumab first.
Eosinophilic (eos >=300) without allergy phenotype: Anti-IL-5 (mepolizumab, benralizumab, reslizumab) or dupilumab. Benralizumab offers 8-week maintenance convenience.
High eos (>=500) + OCS-dependent: Any IL-5 pathway agent with proven OCS-sparing. Benralizumab and dupilumab show strongest OCS elimination rates.
T2-high + multiple T2 comorbidities (AD, CRSwNP, EoE): Dupilumab - addresses all with one biologic.
T2-low (eos less than 150, FeNO less than 25): Tezepelumab - the only biologic with demonstrated efficacy in this population.
Uncertain or mixed phenotype: Tezepelumab (no biomarker threshold) or dupilumab (broader biomarker criteria).

Switching Between Biologics

Biologic switching occurs for (1) primary non-response - insufficient benefit after 4-6 months; or (2) secondary loss of response - initial benefit followed by waning efficacy. When switching: no formal washout period is required for safety; reassess biomarkers and phenotype at time of switch - disease phenotype can shift over time.

Safety Across All Biologics

Infection risk: No class-wide increased risk of serious infections. Biologics target specific cytokine pathways and do not cause broad immunosuppression.
Immunizations: Routine immunizations are safe and encouraged. Live attenuated vaccines (LAIV, yellow fever, oral typhoid) should be avoided while on biologic therapy - use inactivated or subunit alternatives.
Pregnancy: Biologic use in pregnancy is individualized. Uncontrolled severe asthma in pregnancy carries significant risk. For most patients well-controlled on a biologic, continuing is generally preferred over stopping and risking destabilization. Discuss with obstetric team.
Duration of therapy: Severe asthma biologics are generally continued long-term. Discontinuation typically leads to return of eosinophilia and exacerbation risk.

Word-for-word questions to bring to your biologic visit:

Ask: "Based on my eosinophils, FeNO, and IgE, which biologic is the best match for me, and why that one?"
Ask your specialist: "If my eosinophils are low, is tezepelumab (Tezspire) still an option for me?"
Ask: "Will this biologic also treat my nasal polyps or eczema at the same time?"
Ask: "How many months until we know whether it is working, and exactly what will we measure?"
Ask your doctor: "If I am on daily prednisone, what is the plan to taper me off once the biologic works?"
Ask: "Can I inject this at home, and do I need to carry an epinephrine auto-injector afterward?"

Questions to Ask Your Specialist About Biologics

Which biomarkers do I need tested before starting a biologic?
Am I eligible for more than one biologic based on my test results?
Will this biologic also treat my nasal polyps or eczema?
How do I know if the biologic is working - what should I track?
How long before I notice improvement?
Can I self-inject at home, or do I need clinic visits for every dose?
Are there financial assistance programs if my insurance doesn't cover it?
Will I be able to stop my prednisone if the biologic works?
What happens if the first biologic doesn't work - can I try another?
Do I need to carry an epinephrine auto-injector after my injection?
Are there any vaccines I should get before or avoid during treatment?
Is it safe to continue this biologic if I become pregnant?

Lifestyle, Triggers, and Daily Management

Key Principle: Understanding and systematically reducing triggers is a foundational component of severe asthma management that complements - but does not replace - pharmacological treatment. Environmental control, exercise management, and vaccination are all evidence-based interventions that reduce exacerbations independent of biologic therapy.

Allergen Control in the Home

House dust mites: Use allergen-impermeable mattress covers and pillow covers. Wash all bedding in hot water (above 130 degrees F) weekly. Reduce indoor humidity to below 50% - dust mites cannot survive at low humidity. Remove carpeting in the bedroom; hard floors are easier to clean. HEPA vacuum weekly (mite allergens are too small to be captured by standard vacuum filters).

Pet allergens (cat Fel d 1, dog Can f 1): Airborne cat allergen remains detectable in a home for 4-6 months after a cat is removed. Keeping the pet outdoors significantly reduces but does not eliminate exposure. If removal is refused: keep the pet out of the bedroom entirely; use HEPA air purifiers (CADR rating at least 200 for a bedroom); bathe the pet weekly; wash your hands after contact. Allergy shots (SCIT) or sublingual drops for cat/dog allergens are increasingly available and can significantly reduce sensitivity over 3-5 years.

Cockroach allergen (Bla g 2): Primarily a concern in urban housing, especially older apartment buildings. Store all food in sealed containers. Fix leaky pipes (cockroaches need water). Use gel baits rather than sprays (which can be asthma triggers). Seal cracks and gaps in walls and floors. Professional extermination for active infestations.

Mold: Fix all sources of water intrusion promptly. Use bathroom and kitchen exhaust fans during and after showering and cooking. A dehumidifier in damp spaces keeps humidity below 50%. Replace HVAC filters regularly (MERV-11 or higher). Outdoors: avoid leaf blowing and yard work during peak outdoor mold season (late summer, fall).

Outdoor Air Quality and Pollution

Check the Air Quality Index (AQI) at AirNow.gov each morning before outdoor activities. The AQI measures five pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Ozone and PM2.5 are the most relevant for asthma.

AQI 0-50 (Green - Good): No restrictions for most people with asthma.
AQI 51-100 (Yellow - Moderate): Unusually sensitive individuals may be affected. Pay attention to symptoms.
AQI 101-150 (Orange - Unhealthy for Sensitive Groups): Limit prolonged outdoor exertion. Move indoor exercise sessions outdoors only in the early morning before ozone peaks.
AQI 151-200 (Red - Unhealthy): Everyone should limit prolonged outdoor exertion. People with asthma should move all exercise indoors and keep windows closed.
AQI 201+ (Purple or Maroon - Very Unhealthy / Hazardous): Remain indoors with windows closed and HEPA purifier running.

Salt Lake Valley winter inversions: The Wasatch Front experiences some of the worst winter temperature inversions in the United States, trapping PM2.5 at dangerous levels. Monitor the Utah Department of Environmental Quality air quality dashboard (air.utah.gov) for inversion alerts. The State issues mandatory no-burn days during inversions - wood burning significantly raises PM2.5 levels for neighbors. On bad inversion days, commute by enclosed vehicle rather than walking or cycling outdoors.

Pollen Management

Track local pollen counts at AAAAI Pollen Network or pollen.com. Salt Lake City pollen seasons: trees (elm, ash, oak, cottonwood) March-May; grasses (timothy, bluegrass) May-July; weeds and sagebrush August-October.
Keep bedroom windows closed during pollen season. Use air conditioning set to recirculate rather than fresh air intake.
Shower and wash hair before bed on high-pollen days to remove pollen deposited on skin and hair outdoors.
Exercise indoors during peak pollen days or choose late afternoon/early evening (pollen counts are typically lower after rain and in the late afternoon).
Wear wraparound glasses outdoors to reduce eye pollen exposure. Nasal saline rinse after outdoor exposure to clear pollen from nasal passages before it triggers symptoms.
Avoid bringing cut flowers with heavy pollen indoors.

Exercise and Physical Activity

Well-controlled asthma is not a barrier to vigorous physical activity - including competitive athletics. Olympic athletes compete with well-controlled asthma. Exercise has cardiovascular, metabolic, and anti-inflammatory benefits that directly improve asthma outcomes. Exercise-induced bronchoconstriction (EIB) is common but manageable:

Pre-exercise prophylaxis: Your prescribed ICS-formoterol inhaler used 15-30 minutes before exercise provides anti-inflammatory relief at the moment of exercise-induced airway stress. SABA (albuterol) 2 puffs 15 minutes before exercise is also effective for EIB prevention.
Warm-up: 8-10 minutes of moderate-intensity exercise 30-45 minutes before high-intensity effort induces a refractory period (reduced responsiveness) lasting 2-3 hours. Marathon runners and cyclists often use structured warm-ups for this reason.
Swimming: Warm, humidified pool air is the most tolerated exercise environment for asthma. Chloramine exposure (from chlorine reacting with urine and sweat) in highly chlorinated indoor pools can be an irritant - breathe through the nose when possible; outdoor pools are generally better tolerated.
Cold weather exercise: Cover mouth and nose with a scarf or balaclava to warm and humidify inhaled air. Exercise masks (Buff, neoprene face coverings) significantly reduce the temperature drop across inhaled air.
Respiratory physiotherapy: Breathing retraining (Buteyko technique, diaphragmatic breathing) can reduce hyperventilation during exercise and improve perceived breathlessness. Ask your severe asthma team for referral to a respiratory physiotherapist.

Indoor Air Quality and Home Environment

HEPA air purifiers: Use in the bedroom and main living area. Look for CADR (Clean Air Delivery Rate) of at least 200-250 for a standard bedroom. True HEPA filters capture particles down to 0.3 microns, removing most allergens and fine particulate matter. Replace filters per manufacturer's recommendations (typically every 6-12 months).
Gas stoves: Gas cooking appliances emit nitrogen dioxide (NO2) and formaldehyde at levels that can worsen asthma. Use a kitchen exhaust fan venting outdoors (not recirculating) during all cooking. Consider switching to induction or electric cooking, which produces no combustion pollutants.
Scented products: Fragrances - in candles, sprays, plug-in air fresheners, laundry products, and cleaning products - are a common asthma trigger for sensitive individuals. Switch to fragrance-free laundry detergent, cleaning products, and personal care products. Avoid air freshening sprays entirely; use ventilation and odor-removing products instead.
Tobacco and secondhand smoke: Secondhand smoke is among the most potent asthma triggers. Strict no-smoking policy indoors and in vehicles is essential. Thirdhand smoke residue (contaminating surfaces, furniture, and carpets in homes where smoking has occurred) is also an asthma irritant. If a household member smokes, smoking cessation is the most important asthma intervention the family can make.
HVAC maintenance: Replace HVAC filters at least every 3 months with MERV-11 or higher filters. Have ducts professionally cleaned if there is visible mold or heavy dust accumulation. Consider a whole-house HEPA filtration system for severe allergy-asthma overlap.

Vaccination Schedule

Respiratory viral infections are the most common triggers for severe asthma exacerbations. Vaccination is a key prevention strategy:

Annual influenza (flu) vaccine: The inactivated injectable influenza vaccine (IIV or RIV4) is safe and strongly recommended annually. Avoid the live attenuated nasal spray influenza vaccine (LAIV) if on systemic corticosteroids, immunosuppressants, or biologics. Even partial immunity from a mismatched season vaccine reduces severity.
COVID-19 vaccine: COVID-19 infection can trigger severe and prolonged asthma exacerbations. Updated COVID-19 booster (mRNA formulation - Pfizer/Moderna) recommended annually or per current CDC guidance. Do not stop biologics for COVID-19 vaccination.
Pneumococcal vaccination: PPSV23 (Pneumovax) and PCV20 (Prevnar 20) for adults with asthma who are at increased risk from pneumonia. Discuss with your provider - eligibility depends on age, OCS status, and vaccination history.
Shingrix (recombinant zoster vaccine): Recommended for adults >=50 years regardless of prior shingles or varicella history. Two-dose series. Safe with biologics (recombinant/subunit - not live). Important especially for patients on maintenance OCS who have increased herpes zoster risk.
RSV vaccine (Abrysvo or Mresvia): Adults >=60 years. RSV can trigger severe asthma exacerbations in adults. Discuss with provider. Safe with biologics.
Tdap/Td booster: Every 10 years per standard adult immunization schedule. Pertussis (whooping cough) can trigger prolonged cough that worsens asthma.

Occupational Asthma - Protecting Yourself at Work

Occupational asthma (OA) is asthma caused or exacerbated by workplace exposures and accounts for approximately 15-20% of adult-onset asthma. High-risk occupations include: bakers and pastry chefs (flour dust); healthcare workers (latex, glutaraldehyde, cleaning products); automotive painters (isocyanates - HDI, MDI, TDI); agricultural and grain workers (grain dust, storage mites, endotoxin); veterinarians and laboratory animal workers (animal dander); hairdressers (persulfate bleaching agents, formaldehyde); spray painters and foam manufacturers (isocyanates).

If you suspect a workplace trigger: keep a symptom diary correlated with work shifts, note weekends and vacation periods when symptoms improve, and weekday return-to-work worsening. Request a referral to an occupational medicine specialist for formal workplace exposure assessment and serial PEF monitoring. For confirmed sensitizer-induced OA, the only effective treatment is complete avoidance of the causative agent. Employer may be required by OSHA to provide exposure reduction measures. Workers' compensation claims for OA are appropriate when documented. Contact the Association of Occupational and Environmental Clinics (aoec.org) to find an occupational medicine specialist.

Psychological Wellbeing and Stress Management

Living with severe, uncontrolled asthma significantly impacts mental health. Air hunger - the sensation of not being able to breathe - is intrinsically anxiety-provoking. Studies consistently show elevated rates of anxiety and depression in patients with severe asthma (40-50%, compared to 20% in the general population).

Effective approaches:

Cognitive-behavioral therapy (CBT): Strongest evidence base for anxiety associated with asthma. Directly addresses disease-related dysfunctional cognitions (catastrophizing, hypervigilance to breathlessness). Reduces perceived asthma burden and improves quality of life. Ask for a referral to a psychologist familiar with chronic lung disease.
Mindfulness-based stress reduction (MBSR): 8-week structured program showing reduced asthma symptoms and improved quality of life in RCT data. Available in person at many hospitals and online via apps (Calm, Headspace, Insight Timer).
Breathing retraining: Buteyko breathing technique, diaphragmatic breathing, and pursed-lip breathing can reduce hyperventilation and improve perceived breathlessness. Referral to a respiratory physiotherapist.
Peer support: Connecting with others who have severe asthma reduces isolation. AAFA online community (aafa.org), Inspire asthma forum (inspire.com), and Asthma UK patient forum (asthma.org.uk) are all active communities.

Questions to Ask About Lifestyle and Trigger Management

Should I have formal allergy testing to find out exactly which allergens I am sensitized to?
What specific environmental control measures would have the biggest impact on my asthma?
Am I eligible for allergen immunotherapy?
Do I have exercise-induced bronchoconstriction, and what is the best pre-exercise protocol for me?
Is my exercise limitation truly due to asthma, or could VCD be playing a role?
What vaccinations do I need, and are any of them affected by my biologic therapy?
Could my workplace be contributing to my asthma symptoms?
Should I be screened for anxiety or depression, and is behavioral health integrated into my asthma care?
What resources are available for smoking cessation for myself or household members?
What HEPA air purifier would you recommend for my bedroom size?

Caregiver Environmental Checklist: Allergen-impermeable mattress and pillow covers installed and washed monthly; bedroom windows kept closed during pollen season; HEPA air purifier running in bedroom on all nights; no smoking permitted indoors or in shared vehicles; all scented plug-ins and air fresheners removed; pets kept out of bedroom; gas stove exhaust fan used during all cooking; AQI checked each morning before planning outdoor activities.

Clinical Trials in Severe Asthma

Clinical trials are how new treatments prove their safety and effectiveness. Participating gives access to cutting-edge therapies before they reach general availability, provides rigorous monitoring by specialist teams, and contributes to knowledge that benefits future patients. For individuals with severe asthma who have failed multiple biologics, a clinical trial may represent their best available treatment option.

Landmark Pivotal Trials That Defined Current Treatment

NAVIGATOR (NCT03347279) - Tezepelumab: Randomized, double-blind, placebo-controlled trial in 1,061 adults and adolescents. Tezepelumab 210 mg SC q4wks produced a 56% reduction in the annualized asthma exacerbation rate (AAER) overall (70% in the blood-eosinophil >=300 subgroup), with significant reductions across all biomarker subgroups - including patients with blood eosinophils less than 300 cells/microL (T2-low population). Published in NEJM 2021. PMID 33979488.

DESTINATION (NCT03706079) - Tezepelumab long-term: 52-week open-label extension of NAVIGATOR demonstrating sustained exacerbation reduction and continued improvement in lung function (FEV1) and quality of life over 2+ years of treatment. Published in NEJM 2022.

SOURCE (NCT03406078) - Tezepelumab OCS-sparing: Randomized trial in OCS-dependent severe asthma patients. SOURCE DID NOT meet its primary endpoint - the proportion achieving an OCS reduction (75% tezepelumab vs. 66% placebo) was not statistically significant in the overall population; a benefit was observed only in a post-hoc T2-high subgroup. (For OCS-sparing, the positive Phase 3 trials are benralizumab ZONDA and dupilumab VENTURE.)

QUEST (NCT02414854) - Dupilumab: In patients with baseline eosinophils >=300 or FeNO >=25, exacerbation reduction reached 65-70%. Also demonstrated significant FEV1 improvement (+0.32 L in high-type-2 group). Published in NEJM 2018. PMID 29782217.

VENTURE (NCT02528214) - Dupilumab OCS-sparing: In patients requiring daily OCS, dupilumab reduced OCS dose by 70% (median) and eliminated OCS in 48% of patients, vs. 25% with placebo. Published in Lancet 2019.

SIROCCO (NCT01928771) and CALIMA (NCT01914757) - Benralizumab: Exacerbation reductions of 51-59% in patients with severe eosinophilic asthma. Unique feature: q8wks maintenance dosing. Published in Lancet 2016.

ZONDA (NCT02075255) - Benralizumab OCS-sparing: 75% reduction in median OCS dose; 52% of benralizumab patients eliminated OCS entirely vs. 19% placebo. Published in NEJM 2017.

MENSA (NCT01691521) - Mepolizumab: 53% exacerbation reduction with mepolizumab 100 mg SC q4wks in patients with blood eos >=150. Published in NEJM 2014. PMID 25199059.

SIRIUS (NCT01691508) - Mepolizumab OCS-sparing: Median OCS reduction of 50% with mepolizumab vs. no reduction with placebo; 40% of mepolizumab patients eliminated OCS entirely. Published in NEJM 2014.

EXTRA (NCT00314574) - Omalizumab: 25% reduction in clinically significant exacerbations in allergic asthma. Published in Ann Intern Med. 2011 (Hanania et al.).

AIR2 (NCT00231114) - Bronchial Thermoplasty: Sham-controlled trial demonstrating 34% exacerbation reduction and sustained benefit at 5 years with the Alair BT system. Published in Am J Respir Crit Care Med. 2010 (Castro et al.).

AMAZES (ACTRN12609000067268) - Azithromycin: 41% reduction in total asthma exacerbations; 32% reduction in severe exacerbations. Benefit present in both eosinophilic and non-eosinophilic asthma. Published in Lancet 2017. PMID 28687413.

Active and Recruiting Trials - What Is Coming Next

Patients who have failed multiple biologics or who have T2-low asthma without good treatment options should actively explore trial eligibility:

Itepekimab (REGN3500, anti-IL-33): Phase 2 complete in asthma (encouraging in ex-smoker/T2-low populations; Wechsler, NEJM 2021); the Phase 3 program (AERIFY) is in COPD, not asthma. IL-33 is an epithelial alarmin released during allergen exposure and airway injury. Investigational - not FDA-approved.
Abatacept (anti-CD28/CTLA4-Ig): Being explored for T2-low neutrophilic asthma where T-cell co-stimulation may drive inflammation.
Bispecific biologics: Agents targeting two cytokines simultaneously (e.g., IL-4/IL-33, IL-5/TSLP) in early development.
Long-acting inhaled combinations: Triple therapy inhalers (LAMA + LABA + ICS once daily) and ultra-long-acting bronchodilators in late-stage development.
Biologic biosimilars: Biosimilars of omalizumab and mepolizumab entering approval pathways in 2025-2026 will likely reduce costs significantly when available.

How to Find and Join a Clinical Trial

Search tools:

ClinicalTrials.gov: Search "severe asthma" + "recruiting" + your state or nearest metropolitan area. Filter by age, condition, and intervention type. All registered trials are listed here, including contact information for the site coordinator.
AAAAI Clinical Trial Finder (aaaai.org): Specialty society resource focused on allergy/immunology trials.
ResearchMatch.org: Connects patients with researchers at academic centers.

Mountain West and Utah trial sites:

University of Utah Division of Allergy and Immunology: 801-581-7806. Participates in Phase 2-3 biologic trials.
Huntsman Cancer Institute / University of Utah Asthma Program: 801-585-0303. Contact for current severe asthma studies.
National Jewish Health, Denver: 720-859-1000 | 1400 Jackson St, Denver, CO 80206. One of the highest-volume asthma clinical trial sites in the US; approximately 550 miles from Salt Lake City but routinely enrolls remote patients with telehealth screening visits.
University of Colorado, Aurora: 720-848-0300. Approximately 550 miles; active respiratory disease research program.

Questions to Ask When Considering a Clinical Trial

Am I eligible for any current severe asthma trials based on my biomarker profile and treatment history?
What is the study drug's mechanism, and how does it differ from what I have already tried?
What is the chance I will receive placebo, and for how long?
Will I be allowed to keep my current controller medications during the trial?
What happens at the end of the trial - can I continue the study drug, and through what access program?
How many clinic visits are required, and will travel costs be reimbursed?
If I experience a serious adverse event during the trial, what is the protocol?

Specialist Centers and Resources

Mountain West and Utah

University of Utah - Allergy and Clinical Immunology

50 North Medical Drive, Salt Lake City, UT 84132

Phone: 801-581-7806

Services: Biologic initiation and monitoring, allergen immunotherapy, ABPA evaluation, FeNO testing, skin prick and specific IgE testing. Full severe asthma phenotyping. Academic centre with fellowship training.

University of Utah - Pulmonary and Critical Care / Severe Asthma Program

50 North Medical Drive, Salt Lake City, UT 84132

Phone: 801-585-0303

Services: Complex severe asthma evaluation, OCS tapering programs, biologic management, social work and financial navigation for biologic access.

Intermountain Health - Allergy, Asthma and Immunology

Multiple locations across the Wasatch Front and rural Utah

Main line: 801-442-2000

Services: Biologic prescribing, pulmonary function testing, asthma education, allergy testing. Intermountain's size and reach gives it access points across rural and suburban Utah that academic centres cannot match.

VA Salt Lake City Health Care System - George E. Wahlen VAMC

500 Foothill Drive, Salt Lake City, UT 84148

Phone: 801-582-1565

Services: Veteran-specific severe asthma care. Biologic access through VA Pharmacy Benefits Management (PBM) formulary. Veterans who are unable to access biologics through VA may be eligible for Community Care referral to National Jewish Health in Denver.

Nearest Major Referral Centre - National Jewish Health, Denver

National Jewish Health - Denver, Colorado
1400 Jackson Street, Denver, CO 80206
Phone: 720-859-1000 | Toll-free: 1-800-222-LUNG (5864)
Website: nationaljewish.org
Distance from Salt Lake City: approximately 550 miles (8-hour drive; direct flights approximately 1.5 hours)

Ranked #1 US Respiratory Hospital for more than 30 consecutive years by U.S. News and World Report. Full severe asthma programme offering all seven approved biologics, bronchial thermoplasty programme, ABPA specialist evaluation, AERD/aspirin desensitization protocols, dedicated severe asthma nursing coordinators, in-house pulmonary function and FeNO laboratory, and a research programme enrolling patients in clinical trials. Key Clinicians: Drew Kern, MD (severe asthma, biologics); Flavia Hoyte, MD (severe asthma, allergy). Telehealth initial consultations are available for patients who cannot travel.

National Centers of Excellence

Mayo Clinic - Pulmonary and Critical Care Medicine
200 First Street SW, Rochester, MN 55905 | Phone: 507-284-2511
Key clinician: James Li, MD, PhD (immunology and asthma). Also Mayo Clinic Arizona (Scottsdale).
Cleveland Clinic - Respiratory Institute
9500 Euclid Avenue, Cleveland, OH 44195 | Phone: 216-444-2037
Key clinician: Serpil Erzurum, MD (director; eosinophilic asthma, redox biology). Top-5 ranked respiratory hospital nationally. Aspirin desensitization program for AERD.
Brigham and Women's Hospital - Pulmonary and Critical Care Medicine
75 Francis Street, Boston, MA 02115 | Phone: 617-732-5500
Key clinician: Elliot Israel, MD (severe asthma, aspirin desensitization for AERD). Harvard affiliate.
UCSF - Pulmonary, Critical Care, Allergy and Sleep Medicine
505 Parnassus Avenue, San Francisco, CA 94143 | Phone: 415-353-2118
Key clinician: John Fahy, MD (airway biology, mucus in severe asthma, T2-low mechanisms). ABPA specialty care.
Northwestern Medicine - Canning Thoracic Institute
676 North Saint Clair Street, Chicago, IL 60611 | Phone: 312-695-0990
Severe asthma and biologic program; BT-capable center.
Johns Hopkins Hospital - Allergy and Clinical Immunology
1800 Orleans Street, Baltimore, MD 21287 | Phone: 410-955-5000
Severe asthma phenotyping program with active clinical trials.
UPMC - Pulmonary, Allergy and Critical Care Medicine
3601 Fifth Avenue, Pittsburgh, PA 15213 | Phone: 412-648-6161
Emory University Hospital - Pulmonary, Allergy and Critical Care
1364 Clifton Road NE, Atlanta, GA 30322 | Phone: 404-727-5800
Stanford University - Pulmonary and Allergy/Immunology
300 Pasteur Drive, Stanford, CA 94305 | Phone: 650-723-6469

Veterans Affairs

Veterans enrolled in VA healthcare should first establish care with their local VA pulmonology or allergy service. If the local VA cannot provide biologic initiation or bronchial thermoplasty, request a Community Care referral to National Jewish Health Denver or another Centre of Excellence. The VA Pharmacy Benefits Management (PBM) formulary covers all seven FDA-approved severe asthma biologics; prior authorization through VA is required. Veterans outside of a VA catchment area may access care through the MISSION Act community care provisions.

Canada

University of Calgary - Lung Health Clinic
Phone: 403-592-5015. Severe asthma and biologic programme.
University of Toronto - Division of Respirology
Adult programme at Toronto General Hospital (UHN). Active research in severe asthma.
McMaster University - Department of Medicine, Respirology
Hamilton, Ontario; active clinical trials and eosinophilic asthma research.
All provinces cover approved biologics under provincial drug benefit plans, though criteria differ; prior authorization typically required with documentation of Step 4 failure and biomarker eligibility.

International

Royal Brompton Hospital - London, UK
Sydney Street, London SW3 6NP | Phone: +44 20 7352 8121
Key clinicians: Professor Sebastian Johnston (viral-induced asthma); Professor Kian Fan Chung (severe and refractory asthma). Part of the NHS Severe Asthma Network; ERS SHARP registry contributor.
University Medical Centre Groningen (UMCG) - Netherlands
Key clinician: Professor Dirkje Postma (asthma phenotyping, eosinophilic asthma, sex differences).
Montpellier University Hospital - France
Key clinician: Professor Pascal Chanez (severe asthma, T2-low, CRISALIS network).
Alfred Hospital - Melbourne, Australia
Severe asthma program; biologic initiation; bronchial thermoplasty.
Karolinska University Hospital - Stockholm, Sweden
Severe asthma programme; ERS SHARP network member.

Financial Assistance Programs for Biologics

Biologic therapy for severe asthma typically costs $15,000-$40,000 per year at list price. All approved biologics have manufacturer patient assistance and co-pay support programs. Most patients with commercial insurance pay $0-$25 per month through co-pay cards, and uninsured or underinsured patients may qualify for free medication.

What Severe Asthma Treatment Actually Costs (US List Prices, 2024-2025)

The figures below are approximate US list prices (the "wholesale acquisition cost," or WAC) drawn from manufacturer prescribing information and published 2024-2025 price analyses. List price is almost never what an insured patient pays - it is only the starting point before insurance, rebates, and co-pay assistance. Bring these numbers to your team as talking points, not as bills you should expect, and always verify current pricing because it changes.

Treatment	Typical dose	Approx. list price per dose	Approx. list price per year
Omalizumab (Xolair)	75-375 mg SC every 2-4 wk	$700-$1,500 per 150 mg	$25,000-$60,000
Mepolizumab (Nucala)	100 mg SC every 4 wk	about $3,000 per 100 mg	about $39,000
Benralizumab (Fasenra)	30 mg SC (every 8 wk maintenance)	about $5,700 per 30 mg	about $40,000
Reslizumab (Cinqair)	3 mg/kg IV every 4 wk	$1,000-$2,000 per infusion (weight-based), plus infusion-center fee	$25,000-$45,000
Dupilumab (Dupixent)	200-300 mg SC every 2 wk	about $1,900 per syringe	about $41,000
Tezepelumab (Tezspire)	210 mg SC every 4 wk	about $3,900 per 210 mg	about $47,000
Depemokimab (Exdensur)	100 mg SC every 26 wk	launch price not yet public - verify with GSK	twice-yearly (2 doses/year)

Standard non-biologic asthma medicines are far cheaper (approximate US cash/retail price, 2025 - pharmacy discount coupons are often lower): a generic albuterol rescue inhaler about $30-$70; generic budesonide-formoterol (ICS-formoterol reliever/maintenance) about $60-$150 per inhaler; generic fluticasone-salmeterol (Wixela) about $90-$150; tiotropium (Spiriva Respimat) about $500-$600 brand; montelukast generic about $10-$20 per month; a short prednisone course (generic) about $4-$15; azithromycin (generic) about $15-$30 per course; theophylline generic about $15-$30 per month. Diagnostic tests: a FeNO measurement about $50-$150; office spirometry about $40-$100.

The cost of NOT controlling severe asthma is also real: each severe attack treated in an emergency room costs roughly $1,000-$3,000, and an asthma hospital admission commonly exceeds $10,000; a year of frequent oral-steroid use adds downstream costs from bone loss, diabetes, and cataracts. Reducing these events is a large part of a biologic's value. Budget also for monitoring: a DEXA bone-density scan about $125, and a specialist follow-up visit about $200-$400.

How to bring your own cost down to near zero: commercially insured patients typically pay $0-$25 per month for any biologic through the manufacturer co-pay card; uninsured patients who meet income limits often receive the biologic free through the manufacturer patient-assistance program. If you have Medicare you cannot use manufacturer co-pay cards, but as of 2025 the Inflation Reduction Act caps your total annual Part D out-of-pocket drug spending at $2,000 - a change that makes biologics affordable for many Medicare patients for the first time; independent charities (Patient Advocate Foundation, HealthWell) can cover much of the rest when their funds are open. Plan for possible early-year costs such as a $5,000-$9,000 commercial deductible and roughly $200-$500 of travel if you must reach a distant specialty center.

Ask your doctor: "What is my expected out-of-pocket cost for this biologic under my specific insurance, and can your office run a benefits check before I start?"
Ask: "Can you enroll me in the manufacturer co-pay card or patient-assistance program today?"
Ask: "If my insurance denies the biologic, will you file the prior authorization and the appeal, and what do you need from me?"
Ask your pulmonologist: "Is there a lower-cost generic inhaler that would control my type of asthma before we escalate to a biologic?"

A biologic has a built-in trial period and stop rule. Starting a biologic is not a blind lifelong commitment. Guidelines (GINA 2024/2025) treat the first 4 to 6 months as a defined trial period: your specialist should measure your exacerbations, oral-steroid use, symptom score, and lung function before you start and again after this trial period. The agreed plan should include a clear stop rule - discontinue if there is no meaningful response after the trial period - so you are not paying for, and injecting, a drug that is not helping you. Ask: "What is our stop rule - at what point do we decide this biologic is not working and switch to another?"

Manufacturer Patient-Assistance and Co-Pay Programs

Omalizumab (Xolair) - Genentech Access Solutions: 1-888-249-4918
Mepolizumab (Nucala) - GSK Patient Assistance Program: 1-888-825-5249 | gskforyou.com
Reslizumab (Cinqair) - Teva Compass Program: 1-877-237-4879
Benralizumab (Fasenra) - AstraZeneca Patient Assistance: 1-844-203-7221 | fasenra.com/support
Dupilumab (Dupixent) - DUPIXENT MyWay: 1-844-387-4936 (1-844-DUPIXENT) | dupixentmyway.com
Tezepelumab (Tezspire) - AZ/Amgen Patient Access Program: tezspire.com/support
For Medicare/Medicaid patients: Patient Advocate Foundation Co-Pay Relief: patientadvocate.org; HealthWell Foundation: healthwellfoundation.org; NeedyMeds: needymeds.org
University of Utah social work: 801-585-0303 - can navigate financial assistance for any biologic

Patient Education and Advocacy Resources

Asthma and Allergy Foundation of America (AAFA): aafa.org | 1-800-7-ASTHMA (727-8462)
Allergy and Asthma Network: allergyasthmanetwork.org | 1-800-878-4403
American Academy of Allergy, Asthma & Immunology (AAAAI): aaaai.org
American Thoracic Society (ATS): thoracic.org/patients
Global Initiative for Asthma (GINA): ginasthma.org
ERS SHARP Severe Asthma Registry: ersnet.org/research/sharp/
American Lung Association Lung HelpLine: lung.org | 1-800-LUNGUSA (586-4872)

Questions to Ask at Your First Severe Asthma Specialist Visit

What phenotype of asthma do I have, and what biomarkers confirm this?
Have all my comorbidities been systematically evaluated and treated?
Am I on the right biologic, or is a switch warranted?
Am I a candidate for bronchial thermoplasty, either alone or in addition to a biologic?
Is there a clinical trial I should consider, especially if my current treatment is not working?
What financial assistance is available for my medications, and can a social worker or patient navigator help me access it?
Should I be referred to a center with greater severe asthma specialization, such as National Jewish Health?

International Access and Regulatory Status

Severe asthma biologics have been approved across major regulatory agencies worldwide, though timelines, reimbursement criteria, and access vary significantly by country. The table below summarizes approval status for all seven FDA-approved biologics across key regulatory bodies.

Regulatory Approval Summary Table

Biologic	FDA (USA)	EMA (EU)	NICE (England)	PMDA (Japan)	Health Canada	TGA (Australia)	Notes
Omalizumab (Xolair)	2003 / >=6yr allergic	2005	TA278 (2013) / Severe allergic >=6yr; IgE 30-1,500	2009	2004	2003	Longest track record; biosimilar omalizumab (Omlyclo) EMA approved 2023; biosimilars under FDA review
Mepolizumab (Nucala)	2015 / >=6yr eosinophilic	2015	TA431 (2017) / Blood eos >=300 in prior yr	2016	2016	2016	Also approved for EGPA, HES, CRSwNP across multiple markets
Reslizumab (Cinqair / Cinqaero)	2016 / >=18yr eos >=400	2016	TA479 (2017) / Blood eos >=400; IV only	Limited approval	2017	2017	IV administration limits use vs SC competitors; least prescribed of the anti-IL-5 class
Benralizumab (Fasenra)	2017 / >=12yr eos >=300	2018	TA565 (2019) / Blood eos >=300; q8wk maintenance	2019	2018	2018	Unique q8wk maintenance dosing; also approved EGPA many markets
Dupilumab (Dupixent)	2018 (asthma) / >=12yr; >=6yr 2021	2019	TA806 (2022) / Eos >=300 or FeNO >=25; also CRSwNP	2018 (AD) / 2021 (asthma)	2020 (asthma)	2020	Broadest indication portfolio (AD, asthma, CRSwNP, EoE, PNH, CSU); dual IL-4/IL-13 blockade
Tezepelumab (Tezspire)	2021 / >=12yr; no eos threshold	2022	TA878 (2023) / Uncontrolled on high-dose ICS+LABA; no eos floor	2023	2023	2023	Only biologic with no biomarker threshold; EMA early access France 2022 ahead of full approval
Depemokimab (Exdensur)	Dec 2025 / ≥12yr eosinophilic	Under review	Not yet appraised	Pending	Pending	Pending	First twice-yearly anti-IL-5 (q26w); NIMBLE non-inferiority vs. mepolizumab not met

United Kingdom

NHS prescribing of severe asthma biologics requires a positive NICE Technology Appraisal (TA). The six longest-approved agents (omalizumab through tezepelumab) have received NICE TAs; depemokimab, FDA-approved only in December 2025, is too recent for a NICE appraisal as of this writing. Each TA carries specific eligibility criteria that may differ from FDA labeling. Patients must be under specialist severe asthma clinic care; general practitioners cannot initiate biologics. NHS England maintains the UK Severe Asthma Registry. In Scotland, the Scottish Medicines Consortium (SMC) issues separate reimbursement decisions. For tezepelumab, NICE TA878 (2023) was accepted without a blood eosinophil minimum, reflecting the NAVIGATOR trial data. NHS-designated severe asthma centres include Royal Brompton Hospital (London), Glenfield Hospital Leicester, Wythenshawe Hospital Manchester, and Papworth Hospital Cambridge. The UK Severe Asthma Registry lists all centres at severeasthmahub.co.uk.

Germany

The AMNOG process governs reimbursement through IQWiG (Institut fur Qualitat und Wirtschaftlichkeit im Gesundheitswesen) assessment. Germany generally has broader access than many EU markets due to early benefit assessment allowing temporary unrestricted use pending negotiation. The German Asthma Network (DGP) coordinates severe asthma care; specialist centres include the Mainz University Medical Centre and Klinikum Grosshadern Munich.

France

The Haute Autorite de Sante (HAS) evaluates medical benefit. France was proactive with early access: tezepelumab received a temporary authorization for use (autorisation d'acces precoce) in 2022 before full EMA approval, allowing severe asthma patients early access. French severe asthma networks (e.g., the CRISALIS network) coordinate care across university hospitals. All biologics are reimbursed under social security with specialist prescription requirements.

Japan

The Pharmaceuticals and Medical Devices Agency (PMDA) typically approves agents 1-3 years after FDA, though the gap has narrowed. Dupilumab's asthma indication followed its atopic dermatitis approval by approximately 3 years in Japan. The Japanese Respiratory Society (JRS) and the Japanese Society of Allergology (JSA) jointly publish severe asthma management guidelines broadly consistent with GINA. Reimbursement is managed by the Ministry of Health, Labour and Welfare (MHLW) with uniform co-insurance rates under the national health insurance system.

South Korea, Australia, and Other Asia-Pacific Markets

The Ministry of Food and Drug Safety (MFDS) in South Korea has approved all major severe asthma biologics, generally 1-2 years after FDA approval. The National Health Insurance Service (NHIS) maintains specific reimbursement criteria with blood eosinophil thresholds. In Australia, the TGA approvals closely follow EMA timelines. PBS (Pharmaceutical Benefits Scheme) reimbursement has criteria similar to NICE. China's NMPA has approved omalizumab, dupilumab, and mepolizumab; tezepelumab approval was pending as of 2024. Brazil's ANVISA has approved the major biologics, though access through the public SUS system is limited. India does not have universal reimbursement; Xolair and Dupixent are commercially available at significant cost with no national program.

Low- and Middle-Income Countries

For the majority of the world's 300 million asthma patients, severe asthma biologics remain inaccessible due to cost. The WHO Essential Medicines List includes inhaled corticosteroids, short-acting beta-agonists, and long-acting beta-agonists but not biologic therapies. GINA provides a free downloadable PDF guideline (ginasthma.org) used globally. In resource-limited settings, optimized GINA Step 4 therapy (high-dose ICS plus LABA plus tiotropium) with attention to adherence and inhaler technique represents the standard of care.

International Specialist Centres

Leading international severe asthma programmes include: Royal Brompton Hospital, London (Professor Sebastian Johnston, Professor Kian Fan Chung, switchboard +44 20 7352 8121); Montpellier University Hospital, France (Professor Pascal Chanez); University Medical Centre Groningen (UMCG), Netherlands (Professor Dirkje Postma); Karolinska University Hospital, Stockholm, Sweden; Alfred Hospital Melbourne; Charité University Hospital Berlin. ERS Severe Asthma Registry (SHARP network) connects severe asthma centres across 20+ European countries at ersnet.org/research/sharp/.

Questions to Ask About International Access

If I am traveling internationally for several months, how do I maintain my biologic therapy without interruption?
Does my biologic manufacturer offer a global patient assistance or travel support program?
If I am moving abroad, what documentation does my new specialist need to continue my biologic without restarting from Step 1?
Are there equivalent approved biologics available under different brand names in my destination country?

Treatments That Did Not Work

Understanding why certain therapies failed is as important as knowing what succeeded. These agents are no longer recommended for severe asthma outside of specific circumstances.

Fevipiprant (QAW039) - Anti-CRTH2/DP2 Receptor Antagonist

Fevipiprant, developed by Novartis, blocks the CRTH2 receptor mediating eosinophil and Th2 cell chemotaxis toward prostaglandin D2 (PGD2). Early Phase 2 trials showed biological plausibility. However, the pivotal Phase 3 LUSTER-1 and LUSTER-2 trials (NCT02563067 and NCT02555683) enrolling over 2,200 patients with uncontrolled eosinophilic asthma found no significant reduction in exacerbations compared to placebo. Novartis discontinued development for asthma in 2020. The failure underscored that blocking a single downstream prostaglandin pathway is insufficient when the full IL-4/IL-5/IL-13/TSLP cascade continues unimpeded.

Tralokinumab (Adbry) - Anti-IL-13 Monoclonal Antibody

Tralokinumab specifically neutralizes IL-13. Phase 3 asthma trials STRATOS-1 and STRATOS-2 did not demonstrate consistent exacerbation reduction in unselected severe asthma populations, and the program was terminated for this indication. Tralokinumab subsequently succeeded in atopic dermatitis (approved as Adbry by FDA in 2021). The lesson: asthma may require broader upstream pathway blockade. This informed the success of dupilumab, which blocks both IL-4 and IL-13 signaling through the shared IL-4 receptor alpha subunit.

Lebrikizumab (Ebglyss) - Anti-IL-13 Monoclonal Antibody

Lebrikizumab targets IL-13 with high affinity. Despite positive Phase 2 signals - particularly in patients with high periostin levels - the Phase 3 LAVOLTA-I and LAVOLTA-II programmes failed to demonstrate consistent exacerbation reduction. Lebrikizumab then achieved regulatory approval for atopic dermatitis (Ebglyss, EMA 2023). The back-to-back failures of two anti-IL-13 agents in asthma while both succeeded in atopic dermatitis reinforced the understanding that single IL-13 neutralization cannot fully interrupt asthma's redundant T2 pathways.

Anti-TNF Therapies - Etanercept and Infliximab

TNF-alpha was identified as a potential driver of neutrophilic, T2-low severe asthma. Small Phase 2 studies of etanercept (Enbrel) and infliximab (Remicade) showed modest improvements in some patients. However, the GOF trial in 2013 failed to demonstrate superiority over placebo in severe asthma, while revealing significant risks: increased rates of serious infection and potential malignancy. The combination of lack of efficacy and meaningful safety concerns permanently removed anti-TNF therapy from asthma consideration.

Maintenance Oral Corticosteroids (OCS) as Long-Term Asthma Control

Before the biologic era, maintenance oral corticosteroids were used for patients who could not be controlled on inhaled therapy. While effective at suppressing airway inflammation, long-term OCS carry a cumulative toxicity burden now recognized as severe: osteoporosis and fragility fractures, adrenal suppression, type 2 diabetes and metabolic syndrome, cataracts and glaucoma, cardiovascular disease, weight gain, skin fragility, mood disorders, and growth suppression in children. Current GINA and ATS guidelines strongly prioritize OCS elimination through biologic initiation. Maintenance OCS are now considered a treatment failure state - a sign that a biologic referral is urgently needed, not an acceptable long-term solution. Short courses of OCS (3-7 days at 40-60 mg for exacerbations) remain appropriate and effective.

Theophylline as Primary Severe Asthma Control

Theophylline, a methylxanthine bronchodilator, was a cornerstone of asthma management for decades. In the biologic era it has essentially no role in high-income settings for severe asthma. Its narrow therapeutic index (therapeutic range 10-20 mcg/mL; toxicity begins above 20 mcg/mL), extensive drug-drug interactions (CYP1A2 and CYP3A4), and risk of cardiac arrhythmia, seizure, and nausea at toxic levels make it unacceptable when effective and safer alternatives exist. In resource-limited settings where ICS-LABA is unavailable, low-dose theophylline may be continued pragmatically - but this reflects a lack of access rather than clinical preference.

SABA-Only Therapy at Step 1 - Why GINA Changed

For decades, short-acting beta-agonist (SABA) used on an as-needed basis was the standard recommendation for mild asthma. Evidence accumulated showing that SABA-only use leads to tachyphylaxis (reduced bronchodilator response with overuse), persistent airway inflammation between episodes despite symptom relief, and significantly increased risk of fatal asthma attacks with overreliance (greater than 3 canisters per year associated with increased mortality). GINA 2019 made a landmark revision removing SABA-only from Step 1 recommendations, replacing it with anti-inflammatory reliever (AIR) therapy. Patients who have been using SABA alone for years without ICS should be specifically counseled that this represents undertreated asthma, not adequate control.

Methotrexate as OCS-Sparing Therapy

Low-dose methotrexate (7.5-15 mg weekly) was explored in the 1990s and early 2000s as an immunosuppressive OCS-sparing agent. Meta-analyses showed modest reduction in OCS dose (approximately 4 mg prednisolone equivalent) but with significant monitoring burden: weekly folate supplementation, monthly LFT monitoring, contraception requirements due to teratogenicity, and risks of hepatotoxicity, pneumonitis, and bone marrow suppression. Given that biologics achieve far greater OCS sparing with substantially better safety profiles, methotrexate is no longer recommended and is considered superseded. Patients currently on methotrexate for asthma should discuss biologic transition with their specialist.

Leukotriene Receptor Antagonists (LTRAs) as Monotherapy in Severe Asthma

Montelukast (Singulair) and zafirlukast (Accolate) are effective as add-on therapy in mild-to-moderate asthma and particularly in aspirin-exacerbated respiratory disease (AERD). However, as monotherapy in severe asthma they are insufficient. Critically, in 2020 the FDA added a black box warning to montelukast for serious neuropsychiatric adverse events: agitation, aggression, anxiousness, dream abnormalities, hallucinations, depression, insomnia, irritability, restlessness, suicidal thinking and behavior, and tremor. Montelukast should generally be reserved for patients in whom alternatives are not adequate, and should be avoided in patients with pre-existing psychiatric conditions. Patients using montelukast who notice mood or behavior changes should contact their provider immediately.

Questions to Ask About Treatments Not Recommended

A biologic that didn't work in clinical trials for asthma - why is it still available for other conditions?
My previous doctor had me on long-term prednisone for years - what are the risks and how do I transition off?
I've been using my rescue inhaler daily for two years - does that mean my asthma has been undertreated?
I take montelukast and I've noticed mood changes - is this related and what should I do?
Is there any situation where theophylline would still be appropriate for me?

Glossary

Medical terms used in this guide, explained in plain language.

ACQ (Asthma Control Questionnaire): A validated 7-item patient-reported questionnaire. Scores range 0 (fully controlled) to 6 (severely uncontrolled). ACQ-7 score greater than 1.5 indicates uncontrolled asthma.
ACT (Asthma Control Test): A 5-item patient survey measuring asthma control over the past 4 weeks. Scores 5-25; score of 19 or below indicates not well-controlled asthma.
ABPA (Allergic Bronchopulmonary Aspergillosis): A hypersensitivity reaction to Aspergillus fumigatus (a common mold) in the airways. Characterized by central bronchiectasis, markedly elevated total IgE (usually greater than 1,000 IU/mL), positive Aspergillus-specific IgE and IgG. Treated with antifungals (itraconazole) and systemic corticosteroids.
ADCC (Antibody-Dependent Cellular Cytotoxicity): The mechanism by which benralizumab depletes eosinophils. By binding IL-5 receptor alpha on eosinophils and attracting NK cells and macrophages, it triggers direct eosinophil killing - a more complete depletion than agents that merely block IL-5 signaling.
AERD (Aspirin-Exacerbated Respiratory Disease): Also called Samter's Triad. A clinical syndrome combining asthma, chronic rhinosinusitis with nasal polyps, and intolerance to aspirin and other NSAIDs (COX-1 inhibitors). Treatment includes aspirin desensitization, nasal steroids, leukotriene modifiers, and dupilumab.
AIR (Anti-Inflammatory Reliever): GINA 2019/2026 terminology for low-dose ICS-formoterol used as a rescue inhaler. This approach treats both bronchoconstriction (formoterol's fast-onset bronchodilation) and airway inflammation (ICS) simultaneously, replacing SABA-only rescue use.
Allergic Asthma: Asthma triggered by allergen sensitization (e.g., house dust mite, pet dander, cockroach, mold, pollen). Characterized by positive skin-prick testing or specific serum IgE to aeroallergens. First target of biologic therapy (omalizumab).
Atopy: The inherited tendency to develop IgE-mediated allergic responses. Atopic individuals are predisposed to allergic asthma, allergic rhinitis, atopic dermatitis (eczema), and food allergies.
Benralizumab (Fasenra): A monoclonal antibody targeting IL-5 receptor alpha (IL-5Ralpha) on eosinophils and basophils. FDA-approved 2017 for severe eosinophilic asthma in patients 12 years and older with blood eosinophils 300 cells/microL or greater. Unique dosing: 30 mg SC every 4 weeks for 3 doses, then every 8 weeks for maintenance.
Biologic (Biologic Therapy / Monoclonal Antibody): A large-molecule protein therapy derived from biological sources (typically manufactured in cell culture using recombinant DNA technology). Unlike small-molecule drugs (pills), biologics are given by injection or infusion and target specific cytokines or cell surface receptors.
Bronchial Thermoplasty (BT): A bronchoscopic procedure using controlled radiofrequency energy to ablate excess airway smooth muscle. FDA-cleared in 2010 for severe asthma in adults 18 and older not controlled on ICS plus LABA. Performed over three separate bronchoscopic sessions 3 weeks apart.
Bronchoconstriction: Tightening of the smooth muscle surrounding the airways, narrowing the airway lumen and causing wheezing, chest tightness, and shortness of breath. Reversible with bronchodilators (SABA, LABA).
CRSwNP (Chronic Rhinosinusitis with Nasal Polyps): Chronic inflammation of the sinuses and nasal passages resulting in benign tissue growths (polyps). Strongly associated with eosinophilic asthma and AERD. Dupilumab, mepolizumab, and omalizumab are all approved for CRSwNP in addition to asthma.
Dupilumab (Dupixent): A monoclonal antibody blocking the IL-4 receptor alpha (IL-4Ralpha) subunit shared by the IL-4 and IL-13 receptors, simultaneously inhibiting both cytokines. FDA-approved for moderate-to-severe asthma in patients 6 and older. Also approved for atopic dermatitis, CRSwNP, eosinophilic esophagitis, prurigo nodularis, and chronic spontaneous urticaria.
Eosinophil: A type of white blood cell central to T2 airway inflammation in asthma. Blood eosinophils 300 cells/microL or greater suggests eosinophilic asthma likely to respond to anti-IL-5/IL-5R biologics.
Eosinophilic Asthma: An asthma phenotype defined by elevated eosinophils in blood (>=300 cells/microL) or sputum (>=3%). Often late-onset (adult), non-atopic, associated with nasal polyps. The primary target of mepolizumab, reslizumab, and benralizumab.
FeNO (Fractional Exhaled Nitric Oxide): A non-invasive exhaled breath test measuring airway T2 inflammation. FeNO greater than 50 ppb indicates significant eosinophilic airway inflammation. FeNO 25-50 ppb is clinically relevant. FeNO below 25 ppb makes eosinophilic inflammation less likely.
FEV1 (Forced Expiratory Volume in 1 second): The amount of air a person can forcefully exhale in the first second of a spirometry maneuver. The primary measure of airway obstruction. Bronchodilator reversibility (>=12% and >=200 mL improvement) supports the diagnosis of asthma.
GINA (Global Initiative for Asthma): An international scientific organization publishing the Global Strategy for Asthma Management and Prevention - the most widely used asthma guidelines worldwide. GINA 2026 guidelines available free at ginasthma.org.
ICS (Inhaled Corticosteroid): The cornerstone controller medication for asthma. Examples: fluticasone propionate, budesonide, beclomethasone, mometasone. Required at all GINA Steps 2 and above. High-dose ICS (Step 4) is the threshold below which severe asthma (requiring additional therapy) is defined.
IgE (Immunoglobulin E): An antibody class central to allergic reactions. Allergen-specific IgE bound to mast cells triggers histamine and cytokine release upon allergen re-exposure. Total serum IgE above 30 IU/mL with positive specific allergen IgE defines allergic asthma eligible for omalizumab.
ILC2 (Group 2 Innate Lymphoid Cell): Innate immune cells in airway epithelium that are among the first responders to allergen or virus exposure, rapidly releasing IL-4, IL-5, and IL-13 to drive T2 inflammation. Can be activated by TSLP, IL-33, and IL-25 - explaining why tezepelumab (anti-TSLP) can suppress T2 inflammation even in non-atopic patients.
LABA (Long-Acting Beta-Agonist): Inhaled bronchodilators with 12-24-hour duration. Examples: formoterol, salmeterol, vilanterol. Must always be used with ICS in asthma (never as monotherapy due to safety concerns). ICS-LABA combination inhalers are the standard Step 3 and 4 therapy.
Mepolizumab (Nucala): A monoclonal antibody targeting IL-5. FDA-approved 2015 for severe eosinophilic asthma in patients 6 and older. Blood eosinophils >=150 cells/microL required. 53% exacerbation reduction in the MENSA trial. Also approved for EGPA and CRSwNP.
OCS (Oral Corticosteroid): Systemic steroid medications taken by mouth - typically prednisone or prednisolone. Short-course OCS (3-7 days at 40-60 mg) for acute exacerbations is appropriate. Long-term maintenance OCS causes serious cumulative side effects and is now considered a treatment failure state requiring biologic escalation.
Omalizumab (Xolair): The first approved severe asthma biologic (FDA 2003), targeting free IgE. Dose is weight and IgE-based (every 2-4 weeks). Requires IgE 30-700 IU/mL and sensitization to a perennial aeroallergen. Associated with anaphylaxis risk (2-3 per 1,000); patients observed 30 minutes post-injection, carry epinephrine.
Phenotype: In asthma, a clinically observable cluster of characteristics (onset age, triggers, biomarkers, comorbidities) that helps predict treatment response. Major phenotypes include allergic asthma, eosinophilic asthma, AERD, obesity-related asthma, and exercise-induced asthma.
SABA (Short-Acting Beta-Agonist): Fast-onset inhaled bronchodilator used as rescue medication. Albuterol (salbutamol outside the US) is the standard SABA. Relief begins within minutes; duration 4-6 hours. GINA now recommends ICS-formoterol as the preferred reliever over SABA alone at most steps.
SMART Therapy (Single Maintenance And Reliever Therapy): Using a single ICS-formoterol inhaler for both daily maintenance dosing and as-needed rescue. GINA-recommended at Steps 3-5. Formoterol's fast onset makes it suitable as a reliever, while the added ICS dose treats inflammation at each rescue use.
T2-High Asthma: Asthma driven by Type 2 (Th2) immune pathways - characterized by elevated eosinophils, elevated IgE, elevated FeNO, and cytokine signatures dominated by IL-4, IL-5, and IL-13. Approximately 50-70% of severe asthma patients are T2-high. This phenotype responds well to currently approved biologics.
T2-Low Asthma: Asthma without T2 biomarker elevation - normal or low eosinophils, normal FeNO, normal IgE. Often neutrophilic or paucigranulocytic. Associated with obesity, air pollution, smoking, and occupational exposures. Tezepelumab shows efficacy in some T2-low patients.
Tezepelumab (Tezspire): A monoclonal antibody targeting TSLP. FDA-approved 2021 for severe asthma in patients 12 and older. The only approved biologic with no biomarker threshold - can be used regardless of eosinophil count, FeNO, or IgE level. 56% overall exacerbation reduction in the NAVIGATOR trial.
Tiotropium (Spiriva Respimat): A long-acting muscarinic antagonist (LAMA) bronchodilator FDA-approved as add-on therapy at GINA Step 4-5 for patients 6 and older with a history of exacerbations. Provides additional bronchodilation beyond ICS-LABA.
TSLP (Thymic Stromal Lymphopoietin): An epithelial cell-derived cytokine released in response to allergens, viruses, pollutants, and other airway insults. TSLP activates ILC2s, dendritic cells, and mast cells, driving T2 inflammation. As the most upstream therapeutic target in approved asthma biologics, blocking TSLP (tezepelumab) has broader effects than blocking downstream cytokines.
VCD (Vocal Cord Dysfunction) / EILO (Exercise-Induced Laryngeal Obstruction): Paradoxical adduction of the vocal cords during inspiration, causing upper airway obstruction that mimics asthma - particularly during exercise. Key distinguishing features: inspiratory stridor rather than expiratory wheeze; prompt resolution at end of exercise; flat inspiratory loop on flow-volume spirometry; laryngoscopy during symptoms is diagnostic. Treatment is speech therapy.

Key References and Sources

Clinical Guidelines

Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention, 2024 Update. ginasthma.org. Free PDF available for download.
Chung KF, Wenzel SE, Brozek JL, et al. International ERS/ATS Guidelines on Definition, Evaluation and Treatment of Severe Asthma. Eur Respir J. 2014;43(2):343-373. PMID 24337046.
AAAAI/ACAAI Joint Task Force. Allergen Immunotherapy Practice Parameters, 3rd Update. American Academy of Allergy, Asthma and Immunology / American College of Allergy, Asthma and Immunology.
NAEPP Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH/NHLBI, 2007. Available at nhlbi.nih.gov.
NICE Technology Appraisals TA278 (omalizumab), TA431 (mepolizumab), TA479 (reslizumab), TA565 (benralizumab), TA806 (dupilumab), TA878 (tezepelumab). nice.org.uk/guidance.

Landmark Biologic Trials

EXTRA Trial (Omalizumab). J Allergy Clin Immunol. 2009. PMID 19249083. NCT00314574.
Ortega HG, Liu MC, Pavord ID, et al. MENSA Trial (Mepolizumab). N Engl J Med. 2014;371(13):1198-1207. PMID 25199059. NCT01691521.
Bel EH, Wenzel SE, Thompson PJ, et al. SIRIUS Trial (Mepolizumab OCS-sparing). N Engl J Med. 2014;371(13):1189-1197. PMID 25199060. NCT01691508.
Bleecker ER, FitzGerald JM, Chanez P, et al. SIROCCO Trial (Benralizumab). Lancet. 2016;388(10056):2115-2127. NCT01928771.
FitzGerald JM, Bleecker ER, Nair P, et al. CALIMA Trial (Benralizumab). Lancet. 2016;388(10056):2128-2141. NCT01914757.
Nair P, et al. ZONDA Trial (Benralizumab OCS-sparing). N Engl J Med. 2017;376:2448-2458. NCT02075255.
Castro M, Corren J, Pavord ID, et al. QUEST Trial (Dupilumab). N Engl J Med. 2018;378(26):2486-2496. PMID 29782217. NCT02414854.
Wenzel S, et al. VENTURE Trial (Dupilumab OCS-sparing). Lancet. 2019;394:1800-1811. NCT02528214.
Menzies-Gow A, Corren J, Bourdin A, et al. NAVIGATOR Trial (Tezepelumab). N Engl J Med. 2021;384(19):1800-1809. PMID 33979488. NCT03347279.
Wechsler ME, Menzies-Gow A, Brightling CE, et al. DESTINATION Trial (Tezepelumab). N Engl J Med. 2022;386(19):1790-1800. NCT03706079.
Diver S, et al. SOURCE Trial (Tezepelumab OCS-sparing). N Engl J Med. 2022;386:1781-1789. NCT03406078.
Castro M, Rubin AS, Laviolette M, et al. AIR2 Trial (Bronchial Thermoplasty). Am J Respir Crit Care Med. 2010;181(2):116-124. NCT00231114.
Gibson PG, Yang IA, Upham JW, et al. AMAZES Trial (Azithromycin). Lancet. 2017;390(10095):659-668. PMID 28687413.

Regulatory Resources

FDA Drug Approvals - all seven biologics: accessdata.fda.gov/scripts/cder/daf/
EMA - European Public Assessment Reports: ema.europa.eu/en/medicines
ClinicalTrials.gov - severe asthma trials: clinicaltrials.gov (search: severe asthma)
openFDA drug label database: open.fda.gov/drug/label/

Patient and Caregiver Resources

Asthma and Allergy Foundation of America (AAFA): aafa.org | 1-800-7-ASTHMA (727-8462)
Allergy and Asthma Network: allergyasthmanetwork.org | 1-800-878-4403
American Lung Association - Lung HelpLine: lung.org | 1-800-LUNGUSA (586-4872)
National Jewish Health (Denver - #1 US Respiratory Hospital): nationaljewish.org | 1-800-222-LUNG (5864)
GINA Asthma Guidelines (Free Download): ginasthma.org
AirNow - Daily Air Quality Index: airnow.gov
AAAAI Pollen Count: aaaai.org/pollen-count
ERS SHARP Severe Asthma Registry: ersnet.org/research/sharp/
NHS Severe Asthma Hub (UK): severeasthmahub.co.uk
Utah Air Quality (UDAQ): air.utah.gov

Based on: ERS/ATS Severe Asthma Guidelines 2014 (PMID 24337046); GINA 2026; FDA drug labels for omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab (accessdata.fda.gov); NAVIGATOR trial NEJM 2021 (PMID 33979488); QUEST trial NEJM 2018 (PMID 29782217); MENSA trial NEJM 2014 (PMID 25199059); SIROCCO/CALIMA Lancet 2016; EXTRA trial JACI 2009 (PMID 19249083); AIR2 trial NEJM 2010 (PMID 20018959); AMAZES trial Lancet 2017 (PMID 28687413); DESTINATION trial NEJM 2022; SOURCE trial NEJM 2022; Drugs@FDA (accessdata.fda.gov); NICE Technology Appraisals TA278, TA431, TA479, TA565, TA806, TA878; AAAAI/ACAAI joint practice parameters; NHLBI NAEPP EPR-3. This guide does not constitute medical advice. Always discuss treatment decisions with your physician or qualified healthcare provider.

Severe Asthma

Recent Breakthroughs in Severe Asthma

Questions to Ask Your Severe Asthma Specialist

Understanding Severe Asthma

Questions to Ask Your Doctor or Care Team

Diagnosis and Evaluation

Questions to Ask at Your Diagnosis/Workup Appointment