Positive results from the POSEIDON Phase III trial showed AstraZeneca's Imfinzi (durvalumab) and tremelimumab, when added to platinum-based chemotherapy, demonstrated a statistically significant and clinically meaningful improvement in overall survival (OS) and progression-free survival (PFS) compared to chemotherapy alone in the 1st-line treatment of patients with Stage IV (metastatic) non-small cell lung cancer (NSCLC).
These results were presented today during a Presidential Symposium at the 2021 World Conference on Lung Cancer hosted by the International Association for the Study of Lung Cancer (abstract PL02.01).
Melissa Johnson, MD, Director of the Lung Cancer Research program at Sarah Cannon Research Institute, and medical oncologist with Tennessee Oncology, PLLC in Nashville, Tennessee, said: "New combinations are increasingly important in addressing the remaining unmet needs that impact patients with metastatic non-small cell lung cancer - especially combinations that have the potential to improve efficacy in patients with lower PD-L1 expression and deliver the long-term survival benefits that have been observed with CTLA-4 inhibition. The results of POSEIDON confirm that tremelimumab added to Imfinzi and chemotherapy is an effective, well-tolerated treatment in this setting."
Susan Galbraith, Executive Vice President, Oncology R&D, said: "The POSEIDON data offer patients further benefit from Imfinzi and are an important validation of our development strategy to explore novel combinations. Adding a short course of tremelimumab to Imfinzi for those patients already receiving chemotherapy, reduced the risk of cancer progressing or death by 28% compared to chemotherapy alone. The results also showed the significant survival improvement did not compromise tolerability in the 1st-line treatment of patients with metastatic non-small cell lung cancer. We look forward to discussing these data with regulatory authorities."
Patients treated with a short course of five cycles of tremelimumab, an anti-CTLA4 antibody, over 16 weeks in addition to Imfinzi and chemotherapy experienced a 23% reduction in the risk of death versus a range of chemotherapy options (based on a hazard ratio [HR] of 0.77; 95% CI 0.65-0.92; p=0.00304). Median OS was 14.0 months versus 11.7 months for chemotherapy. An estimated 33% of patients were alive at two years versus 22% for chemotherapy. This treatment combination also reduced the risk of disease progression or death by 28% compared to chemotherapy alone (HR 0.72; 95% CI 0.60-0.86; p=0.00031) with a median PFS of 6.2 months versus 4.8 months, respectively. The combination delivered a broadly similar safety profile to the Imfinzi and chemotherapy combination and did not lead to an increased discontinuation of treatment.
POSEIDON also tested the combination of Imfinzi plus chemotherapy, which demonstrated a statistically significant improvement in PFS (HR=0.74; 95% CI 0.62-0.89; p=0.00093) versus chemotherapy alone. A positive OS trend observed for Imfinzi plus chemotherapy did not achieve statistical significance.
Summary of OS and PFS1
