Tecentriq, Cotellic combination fails to improve survival in heavily pretreated colon cancer
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The phase 3 IMblaze370 trial evaluating atezolizumab in combination with cobimetinib did not meet its primary endpoint of OS compared with standard-of-care regorafenib for patients with locally advanced or metastatic colorectal cancer, according to the agents’ manufacturer.
Atezolizumab (Tecentriq, Genentech) — a PD-L1 monoclonal antibody — as monotherapy also did not improve outcomes compared with regorafenib (Stivarga, Bayer).
Researchers of the multicenter, open-label, randomized, three-arm IMblaze370 trial analyzed atezolizumab alone or combined with cobimetinib (Cotellic, Genentech) compared with regorafenib among 363 patients with heavily pretreated locally advanced or metastatic colorectal cancer whose disease progressed or who were intolerant to at least two systemic chemotherapy regimens.
Ninety-five percent of the trial population has microsatellite-stable tumors. Previous monotherapy trials showed checkpoint inhibitors lack efficacy as single agents for patients with microsatellite-stable colorectal cancer, which again appeared true in the atezolizumab monotherapy arm of IMblaze370.
Overall, the IMblaze370 trial failed to meet its primary endpoint of OS.
Safety for the combination of atezolizumab and cobimetinib appeared to be consistent with the known safety profiles of the individual agents. Researchers observed no new safety signals.
“[Although] these results are not what we hoped for, we remain committed to applying our deep experience to develop medicines that will improve outcomes for people living with gastrointestinal cancers,” Sandra Horning, MD, chief medical officer and head of global product development at Genentech, said in a press release. “In particular, we have a number of studies evaluating medicines in colorectal cancer that could play an important role in the treatment of people with this disease in the future.”
Atezolizumab is indicated for certain patients with urothelial carcinoma and non-small cell lung cancer.