AACR: Bristol-Myers Squibb's Opdivo-Yervoy duo provokes response in rare tumors

ATLANTA—Bristol-Myers Squibb has found success with its Opdivo-Yervoy combo in treating various common tumors. But it turns out the duo can help some patients with rare tumors, too.

Sunday at the American Association for Cancer Research annual meeting, researchers unveiled data from an investigator-sponsored phase 2 study showing Opdivo and Yervoy could produce a benefit in patients with neuroendocrine tumors in various parts of the body.

In a study of 33 patients, 24% responded to therapy, with one patient’s cancer disappearing completely. But among patients with high-grade cancer cells—which tend to grow and spread more quickly—response figures were higher: 42%, or 8 of 19 patients, recorded a response to the combo, while none of the patients with low- or intermediate-grade cancer did.

Based on those numbers, researchers concluded that “further investigation of this combination is warranted,” they said in the study abstract. And meanwhile, they have an idea as to why the BMS pairing only turned up a benefit in high-grade patients.

“One preliminary hypothesis for this finding is that high-grade neuroendocrine carcinomas may have a higher tumor mutational burden (TMB), which is an indicator of better response to immunotherapy,” lead study investigator Sandip Patel, M.D., said in a statement.

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Bristol-Myers itself has been working to prove the link between TMB and Opdivo-Yervoy efficacy as it chases an indication in previously untreated non-small cell lung cancer, which is considered immuno-oncology’s largest market. After trumpeting positive data at last year’s AACR meeting, the company in October acknowledged that in a new analysis, the combo’s survival benefit in patients with high TMB and low TMB appeared “quite similar (based on hazard ratios compared to chemotherapy),” as Credit Suisse analyst Vamil Divan put it.

“This leads us to wonder why regulators would approve the regimen strictly for patients with high TMB as per the current filing,” he wrote at the time. And Bristol didn’t wait to find out: It pulled its application in January, citing a need for more data.

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Meanwhile, though, Patel and his colleagues say they’ve already scored with the study. “Our study highlights the feasibility of performing clinical trials among patients with rare cancers,” he said, noting rare tumor types represent “nearly a quarter of all cancers.”

The study “hopefully will help dispel the belief that clinical trials are not feasible for this patient population,” he added.