FDA, Results

What’s killing patients in Bayer’s Xofigo combo study? Researchers unblind study early to probe safety alert

Back in the spring of 2016, researchers reported that a combination of Bayer’s Xofigo (radium-223) with Zytiga (abiraterone) came through with evidence of significantly reduced bone pain for men suffering from prostate cancer. But scientists were forced to unblind the Phase III pivotal trial prematurely after an independent monitoring group spotted a higher rate of deaths in the treatment arm.

Mike Devoy

The company, which has been pursuing new cancer drugs as a core approach to pipeline construction, had enrolled 806 patients who either got the combo or just Zytiga, a well established blockbuster that helped change the standard of care in prostate cancer.

Now they’ll begin the work needed to see why adding Xofigo — which uses targeted alpha radiation to kill cancer cells — would also trigger more deaths and fractures. This combination has been a key part of Bayer’s strategy to expand its market for Xofigo, which hit the market with bullish peak sales estimates of $1.5 billion.

The combo study is being done at a time thousands of new match-up studies are being pursued, working under the reasonable assumption that combining cancer drugs may well offer a longer and better life for cancer patients. But they’re not always safe, as the recent issues with a slate of combinations matching Celgene’s multiple myeloma drugs with checkpoint therapies underscores — a combo suspended after investigators tracked a higher death rate in the treatment arm.

“Patient safety is our top priority. We are therefore unblinding the study to thoroughly analyze the data”, said Mike Devoy, the chief medical officer at Bayer. “It is important to note that, based on available data from previous trials as well as real-world use, the benefit-risk profile of Xofigo in its approved indication remains favorable. We remain committed to further exploring the potential of radium-223 across multiple tumor types with significant unmet medical need, including prostate cancer.”

Image: Shutterstock

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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