Clovis' Rubraca nabs prostate cancer OK, but Big Pharma competition looms

Rubraca AstraZeneca
Clovis' Rubraca has struggled to live up to sales expectations against the likes of AstraZeneca and Merck's Lynparza and GlaxoSmithKline's Zejula. (Clovis Oncology)

It’s official: Clovis Oncology’s Rubraca has beaten AstraZeneca and Merck’s Lynparza into the prostate cancer field. But soon, the small biotech may have to contend with the Big Pharma partners in the marketplace, which could prove more difficult.

The FDA green-lighted Rubraca Friday for men with BRCA-mutated metastatic castration-resistant prostate cancer who have already received a hormonal therapy and chemo. The approval is an accelerated one, meaning Clovis may be on the hook to show the drug can replicate positive study results in a confirmatory trial.

Regulators based the speedy OK on data from the single-arm, phase 2 Triton2 study, which showed Rubraca could spur a benefit in 44% of patients. “The data from the Triton2 clinical trial supporting the FDA approval of Rubraca in mCRPC have been highly consistent over time," Clovis CEO Patrick Mahaffy said in a statement.

RELATED: Clovis investors lose faith as Rubraca struggles against Big Pharma's marketing giants

The regulatory win provides a much-needed boost for Clovis, which has struggled to gain traction in the PARP market against its Big Pharma rivals. Lynparza, GlaxoSmithKline’s Zejula and Pfizer’s Talzenna round out the group (although Talzenna and Rubraca don’t compete directly). Thanks in part to that plethora of contenders, Rubraca hasn’t lived up to sales estimates, a fact that has sparked round after round of buyout speculation.

It’s Lynparza that may soon prove to be a thorn in Clovis’ side as it launches Rubraca into prostate cancer, though. AZ and Merck’s star is expecting its own prostate cancer OK in the second quarter after posting randomized phase 3 data showing it could not only top standard-of-care meds at fending off cancer progression, but at extending lives, too. And Lynparza could net a wider label after showing benefits in not only BRCA-mutated patients, but also those bearing ATM mutations—not to mention broader reimbursement coverage.

RELATED: AstraZeneca, Merck's Lynparza gets an edge over Clovis' Rubraca with prostate cancer survival win

“We …believe that Lynparza’s strong randomized data versus standard of care Xtandi or Zytiga may better facilitate reimbursement and uptake versus Rubraca’s single-arm study, especially with an overall survival advantage,” Leerink Partners analyst Andrew Berens wrote to clients last month.