Imfinzi + tremelimumab showed improved survival in POSEIDON trial

Positive high-level results from the final analysis of the Phase III POSEIDON study showed the combination of Imfinzi (durvalumab), tremelimumab and chemotherapy demonstrated a statistically-significant and clinically-meaningful overall survival (OS) benefit versus chemotherapy alone, in the first-line treatment of patients with Stage IV (metastatic) non-small cell lung cancer (NSCLC), said UK pharma major AstraZeneca (LSE: AZN).

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.