An estimated 31.4% of people with non-squamous cell non-small cell lung cancer treated with the combination were alive at 3 years, compared with 17.3% for those on chemotherapy alone.
A limited course of tremelimumab, when added to durvalumab (Imfinzi; AstraZeneca), plus 4 cycles of chemotherapy has demonstrated sustained improvement in overall survival (OS) compared to chemotherapy alone in the first-line treatment of people patients with metastatic non-small cell lung cancer (NSCLC), according to the results of a study presented at the 2022 congress of the European Society for Medical Oncology.
After approximately 4 years of follow-up from the Phase 3 POSEIDON trial, additional exploratory post-hoc analyzes continued to show improvement in OS with the combination in people with STK11, KEAP1and kras– Mutated NSCLC and individuals whose tumors were PD-L1-negative.
“These updated POSEIDON results after nearly 4 years of follow-up show further evidence that adding limited treatment with tremelimumab to [durvalumab] plus chemotherapy improves outcomes for metastatic [NSCLC] cancer patients, including those with specific tumor mutations, for whom a high unmet need for effective and well-tolerated treatments remains,” said Susan Galbraith, executive vice president of oncology research and development at AstraZeneca, in a press release.
Data show that a 5-cycle course of tremelimumab added to durvalumab and platinum-based chemotherapy improved OS by 25% compared to chemotherapy alone. Investigators observed an updated median OS of 14 months for the combination and 11.7 months for chemotherapy alone.
In addition, approximately 25% of patients treated with the combination were alive at 3 years compared to 13.6% for those treated with chemotherapy alone.
In addition, a trend of improved OS continued to be observed in people with STK11, KEAP1and kras– mutated metastatic NSCLC when treated with the combination, and reduced the risk of death by 38%, 57% and 45%, respectively.
The combination also extended the long-lasting benefits of SG to people with less than 1% PD-L1 tumor cell expression. Consistent with previous POSEIDON data, the benefit of OS in the updated results was more pronounced with tremelimumab plus durvalumab and chemotherapy in people with nonsquamous NSCLC histology.
There was a 32% improvement in OS for the combination compared to chemotherapy alone and an updated median of 17.2 months compared to 13.1 months, respectively. In addition, an estimated 31.4% of people with non-squamous NSCLC treated with the combination were alive at 3 years, compared to 17.3% for those on chemotherapy alone.
Investigators also found that the combination was well tolerated and no new safety signals were identified based on serious adverse events (AEs) reported during follow-up of approximately 4 years. Serious AEs of any grade were observed in 27.6% of people in the combination arm and 17.7% in the chemotherapy alone arm.
Investigators cautioned that interpretations of the data should be viewed with caution due to small sample sizes. Tremelimumab is being reviewed by global regulatory authorities for use in combination as a first-line treatment for metastatic NSCLC based on these results.
Exploratory analysis of the Phase III POSEIDON trial also showed trends in overall survival benefit with limited treatment of tremelimumab added to Imfinzi and chemotherapy in subgroups with high unmet need . Press release. AstraZeneca. September 11, 2022. Accessed September 12, 2022. https://www.astrazeneca.com/media-centre/press-releases/2022/imfinzi-and-tremelimumab-with-chemotherapy-demonstrated-sustained-survival-benefit-in – metastatic-non-small-cell-lung-cancer.html