Paul A. Bunn Jr, MD
Findings from the phase III IMpower150 trial presented at the 2017 ESMO Immuno-Oncology Congress demonstrated that treatment with the combination of atezolizumab (Tecentriq), bevacizumab (Avastin), carboplatin, and paclitaxel delayed progression or death by 38% compared with bevacizumab and chemotherapy alone for patients with nonsquamous non–small cell lung cancer (NSCLC).
in Lung Cancer, shared his expert opinion on the IMpower150 study and other immunotherapy combinations in NSCLC.
OncLive: Can you discuss the results of the IMpower150 study?
One issue about immunotherapy is that a minority of patients respond to it—that is, only about 20%. Therefore, we were wondering if you combined a single-agent checkpoint inhibitor with other immunotherapies, chemotherapies, or antiangiogenic agents, would you have a higher response rate and better overall outcome?
This is the first trial that looked at chemotherapy versus chemotherapy plus a checkpoint inhibitor to present randomized phase III data. It is always better to be first; however, the combination of pembrolizumab (Keytruda) with chemotherapy for nonsquamous NSCLC has already been approved by the FDA because of randomized phase II data.
How does the pembrolizumab and chemotherapy combination compare with the atezolizumab combination?
The median OS in cohort G of KEYNOTE-021 had not been reached for the combination arm. However, at 18 months, 70% of patients were alive and the OS for the chemotherapy arm was 20.9 months. The IMpower150 trial is a similar population, but the median OS for arm B was 19.2 months. In this study, at 18 months, 55% of patients were alive. The chemotherapy arm had an OS of 14.4 months. They are different trials, making it difficult to compare, but the long-term survival of the atezolizumab combination does not seem quite as good as the pembrolizumab combination.
The chemotherapy arm, arm A, in the IMpower150 study is not as good as the bevacizumab arm. Cross comparisons are complicated, but 4-drug combinations are going to be more expensive than 3-drug combinations. In general, OS tends to become more impressive as time goes on. These data were from an early time.
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