The Asthma Landscape Across the United States
Asthma touches every corner of the country, but not evenly. Data from the CDC shows that non-Hispanic Black children and adults carry a heavier burden of the disease compared to non-Hispanic White populations. Prevalence among adults has been climbing over the past decade, while rates among children have shown a gradual decline. Asthma-related emergency department visits and hospitalizations have dropped since 2010, which is encouraging, but the day-to-day struggle for many patients remains real.
Regional differences matter too. Urban centers like Chicago, Detroit, and parts of the Southeast report higher asthma-related hospital admissions, often linked to air quality, housing conditions, and access to specialty care. In the Southwest, dust and pollen patterns create distinct triggers. These geographic variations mean that clinical trial sites are spread across the country, from major academic medical centers to community-based research clinics.
The treatment landscape has shifted dramatically in recent years. Biologic therapies — medications engineered from living cells that target specific inflammatory pathways — have changed the conversation for people with moderate to severe persistent asthma. Tezepelumab, a biologic that blocks TSLP (an upstream inflammatory signal), was studied in the Phase 4 PASSAGE trial, which specifically enrolled patients often excluded from earlier research, including Black and African American participants, adolescents, smokers, and those with overlapping asthma and COPD. Results presented at the 2026 ATS International Conference in Orlando showed that the drug reduced exacerbations across these diverse groups, giving clinicians more confidence in prescribing it to a broader range of patients.
At the same time, AstraZeneca's triple-combination inhaler Breztri Aerosphere received FDA approval in April 2026 for asthma in patients aged 12 and older, following positive Phase III KALOS and LOGOS trial results. A single device delivering three medications — a corticosteroid, a long-acting beta-agonist, and a long-acting muscarinic antagonist — marks a shift toward simplifying treatment for patients who previously juggled multiple inhalers.
What Joining a Trial Actually Looks Like
Clinical trials move through phases, each with a distinct purpose. Phase 1 studies test safety in small groups, often with healthy volunteers. Phase 2 explores dosing and early effectiveness in people with the condition. Phase 3 compares the investigational treatment against a placebo or existing therapy in large populations. Phase 4, like the PASSAGE study, gathers real-world evidence after a drug is already on the market.
For someone with asthma, the most common entry points are Phase 2 through Phase 4 studies. A trial might involve trying a new biologic injection, testing a digital inhaler sensor that tracks usage, or comparing two established medications head-to-head. The National Institutes of Health also runs observational studies, such as the NHALES asthma study at the NIEHS campus in North Carolina, which examines how environmental factors like bacteria and mold affect people with moderate to severe asthma.
The commitment is not trivial. Participants typically attend regular clinic visits — sometimes monthly, sometimes weekly — for lung function tests, blood draws, symptom questionnaires, and medication adjustments. Spirometry, a test where you blow hard into a tube, is a staple of nearly every asthma trial. Some studies also use methacholine challenge tests to measure airway reactivity, or collect sputum samples to analyze inflammation at the cellular level.
| Trial Type | What It Involves | Typical Duration | Best For | Key Considerations |
|---|
| Phase 2 Biologic Trial | Monthly injections or infusions of an investigational antibody | 6–12 months | People with moderate-to-severe allergic or eosinophilic asthma not controlled on standard therapy | May involve placebo group; requires frequent blood monitoring |
| Phase 3 Inhaler Study | Using a new combination inhaler daily and recording symptoms | 12–52 weeks | Patients whose asthma remains uncontrolled on current inhalers | Often includes a run-in period on current medication; rescue inhaler use tracked closely |
| Phase 4 Real-World Study | Continuing prescribed treatment while researchers collect data | 6 months–2 years | Broad patient populations, including those with comorbidities | Less restrictive than earlier-phase trials; medication is already FDA-approved |
| Observational/Registry Study | No intervention — periodic surveys and clinic visits | 1–5 years | Anyone interested in contributing to asthma research | No experimental treatment; lowest risk; may offer modest compensation for time |
Finding the Right Trial and Getting Through the Door
ClinicalTrials.gov, maintained by the National Library of Medicine, lists thousands of actively recruiting asthma studies. The search filters let you narrow by location, phase, age group, and whether the study is currently accepting participants. Large academic centers — think University of Michigan, Johns Hopkins, UCSF, Duke, and Mayo Clinic — run multiple asthma trials at any given time. Community hospitals and private research clinics also serve as trial sites, especially in cities like Phoenix, Dallas, and Atlanta.
Eligibility criteria are strict and vary widely. A trial testing a biologic for severe eosinophilic asthma might require a blood eosinophil count above a certain threshold and a history of at least two exacerbations in the past year despite high-dose inhaled therapy. Another study looking at a new rescue inhaler might only enroll people with mild intermittent asthma. Smoking history, age, current medications, and pregnancy status all factor into the screening process.
Michael, a 47-year-old teacher from St. Louis, struggled for years with asthma that flared every winter despite maximum-dose inhalers and regular prednisone bursts. His pulmonologist referred him to a Phase 3 trial for a long-acting biologic. "I was nervous about the injections at first," he said, "but the study coordinator walked me through every step. My exacerbations dropped from four per year to one, and I stopped needing oral steroids." His experience is not unusual — many trial participants report that the structured monitoring alone improves their asthma management, regardless of whether they receive the active drug.
Costs, Compensation, and Practical Matters
Most clinical trials cover the investigational medication and study-related procedures at no cost to participants. Routine care that you would need regardless of the trial — like a standard checkup — typically remains billed to your insurance. Some studies reimburse for travel or provide a stipend for time and inconvenience, but amounts vary considerably and depend on the trial's funding, the number of visits required, and the procedures involved.
Before signing a consent form, ask the study coordinator these questions: What is the time commitment per visit? Will I need to stop my current medications during a washout period? Is there a chance I will receive a placebo, and for how long? What happens if my asthma worsens during the trial? Can I withdraw at any time without penalty? A reputable research team will answer each of these clearly and without pressure.
The American Lung Association maintains a resource hub linking patients to research opportunities, and organizations like the Allergy & Asthma Network offer educational materials about clinical trial participation. Patient advocacy groups can also connect you with trials specifically recruiting from underrepresented communities — an important consideration given the well-documented disparities in asthma outcomes.
Taking the Next Step
Exploring clinical trials does not mean abandoning your current care. It means adding a layer of possibility. The first move is a conversation with your pulmonologist or allergist, who can assess whether your asthma severity and treatment history align with active studies in your area. From there, searching ClinicalTrials.gov with your ZIP code and condition keywords will surface local options. If the number of results feels overwhelming, focus on trials in Phase 3 or 4 — these involve treatments with established safety data.
The asthma research community is actively seeking participants who reflect the full diversity of people living with the disease. Recent trials like PASSAGE demonstrate that the field is moving toward more inclusive study designs, but recruitment gaps persist. For patients who have been told their asthma is "difficult to treat" or who find themselves cycling through the same medications with diminishing returns, a clinical trial might be the next step worth exploring.
研究の知恵