Gossamer Bio (GOSS) Emerging Growth Conference 79 summary

Market opportunity and disease focus

• Seralutinib targets pulmonary arterial hypertension (PAH) and PH associated with interstitial lung disease, representing a $6–$10 billion market opportunity.

• PAH affects about 50,000 people in the US, with similar prevalence in the EU, Japan, and Australia.

• Median mortality for PAH is about five years, and even lower for PH-ILD, highlighting the urgent need for new therapies.

• Seralutinib is designed as an inhaled therapy, offering targeted delivery and reduced systemic side effects.

• Patent protection extends until 2039, with orphan drug designations in the US, EU, and Japan.

Clinical data and competitive landscape

• Phase II TORREY study showed a 14% reduction in pulmonary vascular resistance (PVR) at 24 weeks, with greater efficacy in sicker patients.

• At 72 weeks, patients on seralutinib achieved a 25% mean reduction in PVR, matching results seen with Merck’s sotatercept but with fewer side effects.

• Sotatercept, approved in March 2024, has significant safety concerns, including bleeding and hospitalizations, creating an opportunity for seralutinib.

• Seralutinib’s side effects are mainly mild, such as cough and minor headache, with no serious safety issues reported.

• Key opinion leaders have recognized seralutinib as a leading therapy in PH due to its efficacy and safety profile.

Ongoing and future clinical development

• The multinational phase III PROSERA study is enrolling about 350 sicker PAH patients, with completion expected in Q2 2024 and top-line data in Q4 2024.

• A phase III trial in PH-ILD is planned, targeting a larger patient population with limited current treatment options.

• Inclusion criteria for PROSERA ensure enrollment of patients with more severe disease, increasing the likelihood of demonstrating efficacy.

• Open-label extension data suggest sustained and increasing efficacy over time.

• Additional indications, such as idiopathic pulmonary fibrosis and PH associated with COPD, are being considered.