Imfinzi + tremelimumab + chemotherapy demonstrated overall survival benefit in POSEIDON trial for 1st-line stage IV non-small cell lung cancer.- AstraZeneca

POSEIDON was a Phase III trial of AstraZeneca’s Imfinzi (durvalumab) plus platinum-based chemotherapy or Imfinzi, tremelimumab and chemotherapy versus chemotherapy alone in the 1st-line treatment of patients with Stage IV (metastatic) non-small cell lung cancer (NSCLC). Positive high-level results from the final analysis of POSEIDON showed the combination of Imfinzi, tremelimumab and chemotherapy demonstrated a statistically significant and clinically meaningful overall survival (OS) benefit versus chemotherapy alone. This immunotherapy combination also demonstrated a statistically significant improvement in progression-free survival (PFS) versus chemotherapy alone, as previously reported in October 2019. Patients in this arm were treated with a short course of tremelimumab, an anti-CTLA4 antibody, over a 16-week period in addition to Imfinzi and standard chemotherapy. The Imfinzi plus chemotherapy arm demonstrated a statistically significant improvement in PFS versus chemotherapy in the previous analysis, but the OS trend observed in this analysis did not achieve statistical significance. Patients in the control arm were treated with up to six cycles of chemotherapy, while those in the experimental arms were treated with up to four cycles. Each combination demonstrated an acceptable safety profile, and no new safety signals were identified. The combination with tremelimumab delivered a broadly similar safety profile to the Imfinzi and chemotherapy combination and did not lead to an increased discontinuation of treatment.