IMpower131 Study: Atezolizumab Plus Chemotherapy in Advanced Squamous NSCLC
On March 20, Genentech announced that the phase III IMpower131 study met its coprimary endpoint of progression-free survival (PFS) and demonstrated that the combination of atezolizumab (Tecentriq) plus chemotherapy (carboplatin and nanopartical albumin-bound [nab]-paclitaxel [Abraxane]) improved PFS compared with chemotherapy alone in the first-line treatment of patients with advanced squamous non–small cell lung cancer (NSCLC).
Safety for the atezolizumab and chemotherapy combination appeared consistent with the known safety profile of the individual medicines, and no new safety signals were identified with the combination. At this interim analysis a statistically significant overall survival (OS) benefit was not observed and the study will continue as planned. These data will be presented at an upcoming oncology congress.
“Squamous non–small cell lung cancer is difficult to treat and there have been limited new treatment options over the last few decades,” said Sandra Horning, MD, Roche’s Chief Medical Officer and Head of Global Product Development. “We will share the IMpower131 results with global health authorities and we look forward to seeing more mature overall survival data.”
As per the statistical analysis plan in IMpower131, arm B (atezolizumab plus carboplatin and nab-paclitaxel) must demonstrate a statistically significant OS result vs arm C (carboplatin and nab-paclitaxel) before an analysis between arm A (atezolizumab plus carboplatin and paclitaxel) and arm C can be made for PFS and OS.
More About the IMpower131 Study
IMpower131 is a phase III, open-label, multicenter, randomized study evaluating the efficacy and safety of atezolizumab in combination with carboplatin and nab-paclitaxel or atezolizumab in combination with carboplatin and paclitaxel vs chemotherapy (carboplatin and nab-paclitaxel) alone in people with stage IV squamous NSCLC who have not been previously treated with chemotherapy. The study enrolled 1,021 people who were randomized equally (1:1:1) to receive:
- Atezolizumab plus carboplatin and paclitaxel (arm A), or
- Atezolizumab plus carboplatin and nab-paclitaxel (arm B), or
- Carboplatin and nab-paclitaxel (arm C, control arm)
During the treatment-induction phase, people in arm A received four or six cycles of atezolizumab plus carboplatin and paclitaxel, given on day 1 of each 21-day cycle. This was followed by maintenance therapy with atezolizumab every 3 weeks until progression of the cancer, or for as long as clinical benefit was observed.
During the treatment-induction phase, people in arm B received four or six cycles of atezolizumab, carboplatin and nab-paclitaxel. Atezolizumab and carboplatin were administered on day 1 of each 21-day cycle. Nab-paclitaxel was administered on days 1, 8, and 15 of each 21-day cycle. This was followed by maintenance therapy with atezolizumab every 3 weeks until progression of the cancer, or for as long as clinical benefit was observed.
During the treatment-induction phase, people in arm C received four or six cycles of carboplatin and nab-paclitaxel. Carboplatin was administered on day 1 of each 21-day cycle, and nab-paclitaxel was administered on days 1, 8, and 15 of each 21-day cycle. In the maintenance phase, participants received best supportive care.
The coprimary endpoints were PFS as determined by the investigator using RECIST v1.1 in the intention-to-treat (ITT) population (arm B vs arm C) and OS in the ITT population (arm B vs arm C).
IMpower131 met its PFS coprimary endpoint per study protocol. This analysis of IMpower131 evaluated arm B vs arm C.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
