POSEIDON Phase III post-hoc exploratory analyses presented at WCLC 2022

Late-breaking post-hoc exploratory results from the POSEIDON Phase III trial suggest a trend for improved overall survival (OS) with a limited course of five cycles of tremelimumab added to AstraZeneca’s (LSE: AZN) Imfinzi (durvalumab) plus platinum chemotherapy, in the first-line treatment of patients with STK11, KEAP1 or KRAS-mutated Stage IV (metastatic) non-small cell lung cancer (mNSCLC).

These results were presented at the International Association for the Study of Lung Cancer (IASLC) 2022 World Conference on Lung Cancer (WCLC) (Abstract #OA15.04).

NSCLC tumors with STK11 and KEAP1 mutations are often associated with a poor prognosis and frequently classified as immunologically “cold”, with immune T-cells missing from the tumor. KRAS-mutated NSCLC is typically responsive to immunotherapy, unless associated with STK11 or KEAP1 co-mutations where outcomes are often poor. KRAS mutations are the most common tumor growth driver in NSCLC representing approximately 25% of patients; while an estimated 6%-15% of NSCLC is KEAP1-mutated and around 15% of NSCLC is KRAS-driven and STK11-mutated.