Gossamer Bio Announces Topline Results for Phase 2 Trials of Oral GB001 in Asthma and Chronic Rhinosinusitis

– Primary endpoint of asthma worsening not met in LEDA Study, however consistent numeric reductions ranging from 32-35% observed across all three GB001 groups –

– Statistically significant improvements in key secondary endpoint of time to first asthma worsening of 28% and 30% observed for 20 mg and 60 mg doses of GB001, respectively; 23% improvement observed in 40 mg group –

– TITAN Study in chronic rhinosinusitis did not meet primary or secondary endpoints –

– Gossamer to hold webcast to discuss trial results at 8:00 am EDT –

Gossamer Bio, Inc. (Nasdaq: GOSS), a clinical-stage biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutics in the disease areas of immunology, inflammation and oncology, today announced topline results from its Phase 2b LEDA trial in patients with moderate-to-severe eosinophilic asthma and its Phase 2 TITAN trial in patients with chronic rhinosinusitis.

“While we did not achieve statistical significance on the primary endpoint in the LEDA Study, we are encouraged by the consistent results observed for all three doses of once-daily, oral GB001 therapy across the primary and secondary endpoints,” said Sheila Gujrathi, M.D., Co-Founder and Chief Executive Officer of Gossamer. “We believe these data provide important information for designing a well-powered Phase 3 program for GB001 in severe asthma. We plan to engage in global regulatory discussions in order to inform our thinking around potential partnerships or strategic alternatives for this program.”

“The results of the robust LEDA Study are meaningful and help us to further understand the DP2 pathway in asthma,” said Bruce Levy, M.D., Chief, Division of Pulmonary and Critical Care Medicine at Brigham and Women’s Hospital and Professor of Medicine at Harvard Medical School. “I believe GB001 as an oral treatment has the potential to serve the high unmet need of patients with uncontrolled severe asthma.”

LEDA Phase 2b Trial Design

The LEDA trial enrolled 480 patients with uncontrolled, moderate-to-severe eosinophilic asthma and assessed the effect of oral GB001 add-on therapy to standard of care over 24 weeks, comparing three dose groups of once-daily, oral GB001 (20 mg, n=120; 40 mg, n=118; and 60 mg, n=122) to placebo (n=120).

The primary endpoint, asthma worsening, included five components and was chosen for its sensitivity in detecting deterioration in clinical outcome measures known to be correlated with exacerbations. A patient was considered to have experienced asthma worsening if they met any of the five components by Week 24. This endpoint has previously been used in the context of steroid withdrawal studies, including a prior Phase 2 trial of GB001.

LEDA Primary and Secondary Endpoint Results

The primary endpoint of the trial was not met, though consistent and meaningful numeric reductions in the odds of asthma worsening as compared to placebo were observed across all GB001 groups: 33% (p=0.1425), 32% (p=0.1482), and 35% (p=0.1086), for the GB001 20 mg, 40 mg, and 60 mg groups, respectively. In addition, statistically significant improvements in the key secondary endpoint of time to first asthma worsening as compared to placebo