Clovis' Rubraca takes aim at Lynparza, Zejula with priority review for new use

Clovis Oncology
Clovis Oncology CEO Patrick Mahaffey sees opportunity for PARP inhibitor growth beyond ovarian cancer: “We and others will explore and have proven to some extent already the utility of this class of compounds in multiple tumor types, so it’s not limited to these indications,” he told FiercePharma at ESMO.

Clovis Oncology is one step away from a new use for its ovarian cancer drug Rubraca—and with FDA priority review, it could take that step early next year. 

The drug, launched less than a year ago as a third-line treatment for BRCA-positive ovarian cancer, is up for a new approval as a maintenance therapy in women with recurrent disease who've responded, at least partially, to platinum chemotherapy. And that's all women, not just those who've tested positive for BRCA mutations.

Of course, that's up to the FDA and its decision, which the agency has deadlined on April 6. And if the FDA does give its blessing, Clovis won't be alone in the ovarian cancer maintenance field—AstraZeneca's Lynparza and Tesaro's Zejula both are approved for the same use.

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But analysts see the market for maintenance use of these drugs, which are all PARP inhibitors, as a $2 billion opportunity, leaving room for all three to nab significant sales in the indication. Even as the third in the class to win this particular approval, the Clovis therapy would be "very well positioned to capture market share in the large second-line maintenance category pending approval ... based on strong Ariel3 trial results," Leerink analyst Michael Schmidt said in a Wednesday note.

Lynparza was the first PARP drug to hit the scene, back in 2014, with Rubraca following last December and Zejula in May 2017. They're the first new drugs for ovarian cancer in more than a decade, and they've already transformed its treatment for many women.

And the way Clovis sees it, there's an advantage built into the Ariel3 trial data that makes up its application for the new Rubraca use. Unlike some other PARP studies, Ariel3 didn’t limit itself to patients who’d responded completely to platinum chemo. Two-thirds of the participants had only achieved a partial response to chemo, and so investigators could monitor residual tumors to see whether Rubraca could improve on that initial response—and it did, Clovis CEO Patrick Mahaffey said in an interview ahead of the data release this fall.

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Among BRCA-positive patients, 38% showed a treatment response, and 18% saw their residual tumor disappear, Mahaffey said. “What we see with Rubraca is a much more pronounced benefit,” he said in an interview at the time.

“The drug didn’t just maintain the original response, but we can improve on that original response," he added. "Women are acutely aware of the risk and, sadly, the likelihood that the tumor will re-emerge. To be able to tell a patient, you have less tumor now than when you thought you had achieved a benefit from platinum chemotherapy—that is extraordinary.”

Clovis is pushing its Rubraca research forward in other cancers, too, notably prostate and breast cancers, with a pivotal prostate cancer trial expected to read out in the first half of next year. Clovis also has a partnership with Bristol-Myers Squibb to study Rubraca alongside the Big Pharma's immuno-oncology star Opdivo.