Clovis Oncology’s shares got hammered this morning after the biotech revealed some mixed results for its PARP inhibitor rucaparib.
The biotech reported a 54% objective response rate for the drug for BRCA-mutated ovarian cancer, with nine (9%) complete responders and 48 (45%) partial responders. Boring down into the data, investigators also reported zero response among the 7% of the patients who were platinum-refractory, a 25% response rate for platinum-resistant patients and 66% for platinum-sensitive responses.
The median progression-free survival time in the single-arm study was ten months.
Clovis faces tough competition in this field. And investors didn’t like the way the data was breaking down compared to rivals like Tesaro’s niraparib, which was put through a randomized study with a control arm.
Clovis’s stock, which has been zooming up in anticipation of the data, quickly plunged 28% Friday morning. By the end of the day Clovis saw the losses cut to a still painful 18%.
Some analysts quickly noted that the drug doesn’t appear to look good in comparison to AstraZeneca’s Lynparza, approved in late 2014 with its own set of mixed data that drew a rebuke from an FDA panel. AstraZeneca’s data included this note on platinum-resistant patients:
Kaufman et al evaluated olaparib 400 mg bid in a cohort of patients with germline BRCA mutations and advanced solid tumors including 193 patients with platinum-resistant ovarian cancer. In this subset of patients, a tumor response rate of 31.1% was observed with an additional 40% of patients achieving stable disease for at least 8 weeks
Tesaro reported earlier that the niraparib arm hit the primary endpoint of their study with a median PFS of 12.9 months compared to 3.8 months for the control arm. Among germline BRCA mutation patients, the median PFS for patients treated with niraparib was 21.0 months, compared to 5.5 months for control. And it has more data coming up at ESMO this weekend.
The painful reception for the Boulder, CO-based biotech’s data today underscore some serious issues at Clovis Oncology. The company was forced to restate its data submitted for an approval of rociletinib, prompting an embarrassing and devastating drop in the number of responses that the biotech had claimed for their drug. An FDA panel subsequently rejected the drug, prompting Clovis to restructure and lay off staffers.
Now all of its wagons are circled around rucaparib, a PARP that will go head to head with AstraZeneca’s Lynparza as well as quite possibly niraparib. And now Pfizer has talazoparib, another PARP inhibitor now in a pivotal trial that’s shown considerable promise. Rucaparib is ahead of Tesaro’s drug on the regulatory front, with a PDUFA date of February 23.
Clovis can’t afford another failure. But some analysts had been upbeat about rucaparib after the FDA waved a panel review for the drug, which might indicate their support.
(Correction: This story was corrected to take out a reference to the 9 people who died in the study. The Clovis drug was not linked with any of their deaths, according to the biotech.)
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