FDA Approves Exdensur: A Twice‑Yearly Shot That Could Change Life for People with Severe Asthma

Severe asthma can be frightening: sudden attacks, emergency visits, and daily limits on what you can do. On December 16, 2025, the U.S. Food and Drug Administration (FDA) approved Exdensur (depemokimab‑ulaa) as an add‑on maintenance treatment for people aged 12 and older with severe asthma characterized by an eosinophilic phenotype  –  a type of asthma driven by a specific immune cell called an eosinophil. This approval is notable because Exdensur is the first ultra‑long‑acting biologic that only needs two injections per year, offering a simpler schedule for patients who struggle with frequent dosing.

What is Exdensur and why is this approval important?

Exdensur is a biologic medicine developed by GSK that targets interleukin‑5 (IL‑5), a protein that helps eosinophils survive and cause inflammation in the airways. By blocking IL‑5, Exdensur reduces the number of eosinophils and lowers the risk of asthma attacks (exacerbations). What makes Exdensur stand out is its ultra‑long action: it’s designed to be effective with just two injections a year, which could be a big deal for people who find monthly or biweekly shots hard to keep up with.

Many people with severe asthma still have attacks despite inhalers and other medicines. Biologics have helped some of these patients, but uptake has been limited  –  partly because of frequent dosing and access issues. A twice‑yearly option could make it easier for more people to stay on treatment and avoid hospital visits.

What the clinical trials showed

Exdensur’s FDA approval is based on two large Phase III trials called SWIFT‑1 and SWIFT‑2. These were randomized, placebo‑controlled studies that added Exdensur to patients’ usual asthma care and followed them for a year.

• Fewer asthma attacks: In SWIFT‑1, Exdensur reduced the annual rate of asthma exacerbations by 58% compared with placebo; in SWIFT‑2 the reduction was 48%. When the two trials were pooled, Exdensur also showed a 72% reduction in exacerbations that required hospitalization or an emergency department visit.
• Safety: Side effects were similar between Exdensur and placebo in the trials, and there were no treatment‑related deaths reported in the studies used for approval.
• Other outcomes: Some patient‑reported measures like quality of life and symptom scores did not show consistent improvements across all endpoints, which is not uncommon in asthma trials where placebo effects can be strong.

These results suggest Exdensur is particularly effective at preventing serious attacks  –  the kind that land people in the hospital  –  while offering the convenience of only two doses per year.

Who is Exdensur for?

Exdensur is approved as an add‑on maintenance therapy for people 12 years and older with severe asthma with an eosinophilic phenotype. In plain terms:

• “Add‑on” means it’s used in addition to standard asthma medicines (like inhaled steroids and bronchodilators), not as a replacement.
• “Eosinophilic phenotype” refers to patients who have higher levels of eosinophils in their blood  –  a marker doctors use to identify who is likely to benefit from IL‑5 targeted therapies.

If you or a family member has severe asthma and keep having attacks despite regular inhaler treatment, a doctor may check blood eosinophil counts and consider whether a biologic like Exdensur is appropriate.

How is Exdensur given?

• Dosing schedule: Two subcutaneous (under‑the‑skin) injections per year  –  one at the start and one six months later  –  plus continued standard asthma care.
• Where it’s given: Typically in a clinic, doctor’s office, or other healthcare setting where injections are administered and patients can be observed for a short time afterward.

The infrequent dosing is a major selling point: fewer clinic visits, fewer injections, and potentially better long‑term adherence for people who struggle with more frequent schedules.

Benefits and limitations  –  what to expect

Potential benefits

• Big reduction in serious attacks: Trials showed large drops in exacerbations, including those requiring emergency care or hospitalization.
• Convenience: Twice‑yearly dosing could reduce treatment burden and improve adherence for many patients.
• Favorable safety profile: Side effects in trials were similar to placebo, which is reassuring.

Limitations and things to know

• Not everyone will see big improvements in daily symptoms or quality of life: Some secondary measures in the trials were mixed, which means Exdensur’s strongest benefit appears to be preventing severe attacks rather than immediately improving day‑to‑day symptoms for every patient.
• Cost and access: New biologics can be expensive, and insurance coverage varies. GSK has not publicly released U.S. pricing at the time of approval; pricing and access programs will influence how quickly patients can start treatment.
• Specific patient group: It’s approved for the eosinophilic subtype of severe asthma, so it’s not a universal treatment for all asthma patients.

Safety snapshot

Across the SWIFT trials, Exdensur was well tolerated. The overall rate and severity of side effects were similar between Exdensur and placebo groups, and there were no treatment‑related deaths reported in the studies used for approval. As with any biologic, doctors will monitor for injection‑site reactions and other potential immune‑related effects, and they’ll weigh benefits against risks for each patient.

What next?

• Availability: GSK plans to launch Exdensur in the U.S. following FDA approval; the company has indicated a market debut is expected soon after regulatory clearance, with pricing details to come.
• Competition: Exdensur will join a crowded field of asthma biologics, but its twice‑yearly dosing could give it an edge for patients who prioritize convenience.
• Other uses: GSK is exploring Exdensur for other conditions linked to eosinophils and IL‑5 biology; additional approvals could follow if studies are successful.

Sources (6)

1. The American Journal of Managed Care (AJMC)  –  coverage of Exdensur approval and trial results. https://www.ajmc.com/view/fda-approves-depemokimab-for-severe-eosinophilic-asthma 
2. FiercePharma  –  analysis of GSK’s approval, market context, and dosing convenience. https://www.fiercepharma.com/pharma/gsk-rounds-out-year-approvals-fda-asthma-nod-long-acting-biologic-exdensur 
3. Bloomberg  –  news report on FDA approval and GSK’s commercial outlook for Exdensur. https://www.bloomberg.com/news/articles/2025-12-17/gsk-says-us-fda-approved-its-twice-annual-asthma-drug-exdensur 
4. GSK Press Release  –  official company announcement and SWIFT trial topline data. https://us.gsk.com/en-us/media/press-releases/exdensur-depemokimab-approved-by-us-fda-for-the-treatment-of-severe-asthma/ 
5. PharmExec  –  explanation of mechanism, trial basis for approval, and clinical context. https://www.pharmexec.com/view/fda-gsk-exdensur-eosinophilic-severe-asthma 

Applied Clinical Trials  –  detailed summary of SWIFT Phase III data supporting approval. https://www.appliedclinicaltrialsonline.com/view/fda-approves-gsk-exdensur-severe-asthma-swift-data