Bristol Myers, Exelixis scored a kidney cancer combo win. But is there room for their duo on the market?

Bristol Myers Squibb and Exelixis have a potential kidney cancer contender on their hands—but they’ll have to meet a “high bar” to gain traction in the crowded field, one analyst says.

A combination of Bristol’s immuno-oncology star Opdivo and Exelixis’ Cabometyx showed in a phase 3 trial that it could best Pfizer’s Sutent at staving off disease progression in previously untreated renal cell carcinoma patients. The pairing also hit the trial’s secondary endpoints, boosting the proportion of patients who responded to therapy and extending patients’ lives.

The companies are planning to unveil detailed results of the trial, called CheckMate-9ER, at an upcoming medical meeting, and in the meantime they’ll be working toward regulatory filings “in the near future,” Gisela Schwab, M.D., Exelixis’ chief medical officer, said in a statement.

“Given the growing body of data showing that Cabometyx may create a more immune-permissive tumor environment that may enhance response to immune checkpoint inhibitors, we have been eagerly awaiting the results for the combination,” she added.

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But given that Bristol already has a regimen on the market that’s posted strong efficacy numbers—as does its checkpoint rival, Keytruda from Merck & Co.—there’s a “high bar for new regimens” in kidney cancer, Leerink Partners analyst Daina Graybosch wrote to clients Monday.

BMS’ Opdivo-Yervoy duo was the first on the front-line scene, and a marriage of Keytruda and Pfizer’s Sutent follow-up, Inlyta, joined it there a year ago.

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And as key opinion leaders told Graybosch and her colleagues, “clinical results with newer anti-PD1 + TKI regimens would have to be spectacular ... to disrupt current care standards, near-term,” she wrote. Think response rates of around 90% and fewer side effects than the current regimens, she said.

As those doctors see it, “oncologists treating RCC will prioritize long-term survival outcomes in making prescribing decisions”—and Bristol’s I-O duo looks good in that department, having shown it can keep more than half of patients alive at the 42-month mark.

RELATED: BMS leans on new long-term Opdivo data in crowded kidney cancer field

Meanwhile, though, it’s not just Bristol and Exelixis working to find footing for a newcomer regimen. Merck is testing Keytruda alongside Lenvima, a med it shares with Eisai, in the same patient population. That trial is set to wrap up in August.

Assuming the study reads out positively, “Bristol Myers and Merck will each have two competitive immuno-oncology regimens for front-line RCC patients,” Graybosch wrote. And “as the new regimens find their place, we believe the two companies will continue to split share much as in the past.”