Gossamer Bio (GOSS) Investor Presentation - Slideshow

Seralutinib (GB002) for Pulmonary Arterial Hypertension (PAH) - Seralutinib (GB002) is an inhaled PDGFR, CSF1R, and c-KIT inhibitor being developed for PAH, with Phase 2 enrollment completed and topline results expected in the second half of November/first half of December 2022 [4, 6] - The Phase 3 IMPRES study of Imatinib in PAH showed a 32-meter improvement in 6-Minute Walk Distance (6MWD) and a 32% reduction in Pulmonary Vascular Resistance (PVR), but had a high rate of GI side effects (44% SAE rate) and discontinuations (33% for the imatinib group) [12] - Seralutinib is designed for inhalation with limited oral bioavailability (~5%) to mitigate systemic adverse events associated with Imatinib [14] - Preclinical data shows Seralutinib treatment led to a significant improvement in Right Ventricular Systolic Pressure (RVSP) and reduced circulating levels of NT-proBNP in a SuHx PAH study [23] - Phase 1b study in PAH patients showed that all 8 subjects completed the 14-day treatment period, and 2 subjects entered and completed the Open-Label Extension (OLE) receiving 90 mg BID [30] GB5121 & GB7208 for CNS Lymphoma (PCNSL) and Multiple Sclerosis (MS) - GB5121 is a CNS-penetrant BTK inhibitor in Phase 1b/2 development for relapsed/refractory primary CNS lymphoma (PCNSL), while GB7208 is in preclinical development for Multiple Sclerosis (MS) [4, 46] - Preclinical mouse models suggest Gossamer BTK inhibitors have best-in-class CNS penetration [49] - GB5121 and GB7208 are highly selective BTK inhibitors based on kinome scans [52] - In the US, approximately 1,500 new PCNSL patients are diagnosed each year, with a median overall survival (OS) of 26 months [57] Financial Overview - As of June 30, 2022, Gossamer Bio had approximately $342 million in cash, cash equivalents, and marketable securities (pro forma for July 2022 PIPE), $30 million in debt, and $200 million in principal of convertible notes outstanding [73]