Tesaro Jumped on PARP Ovarian Cancer Win Vs. AstraZeneca PLC, AbbVie

Published: Oct 11, 2016

Tesaro Jumped on PARP Ovarian Cancer Win Vs. AstraZeneca PLC, AbbVie October 11, 2016
By Alex Keown, BioSpace.com Breaking News Staff

WALTHAM, Mass. – Since June shares of Tesaro Inc. have soared, nearly tripling in price since early July when the company announced its ovarian cancer treatment, Niraparib, an oral, once-daily PARP inhibitor, met its endpoints of progression-free survival (PFS) in a Phase III trial.

This weekend, the Massachusetts-based company revealed further positive news about niraparib during a presentation at the European Network for Gynecological Oncological Trial groups in Denmark. Company data showed the drug could benefit 70 percent of all ovarian cancer patients who received previous chemotherapy treatments. Tesaro said niraparib increased progression free survival in different cohorts of a 553-patient trial—whether they had the BRCA gene or homologous recombination deficient (HRD) tumors. Trial data showed patients with the BRCA gene had 21 months of progression free survival – 15 months longer than the control group. Additionally, patients in the non-germline BRCA mutant cohort showed progression free survival of 9.3 months, compared to 3.9 months for control.

Patients were also highly tolerant of the PARP inhibitor, with less than 15 percent dropping out of the study, Tesaro said. Patients who did show adverse events were successfully handled with dosing adjustments, the company said.

"These landmark results are extremely encouraging for the ovarian cancer community," Mansoor Raza Mirza, the lead investigator of the trial said in a statement. "The effectiveness of platinum-based chemotherapy diminishes over time, and PFS and platinum-free intervals generally become shorter after each round of platinum treatment. In addition, the incidence of infection and risk of neuropathy and hypersensitivity with certain chemotherapy agents rises with subsequent cycles. An oral maintenance treatment that could lengthen the PFS interval between rounds of platinum-based chemotherapy would be very meaningful for patients with ovarian cancer, who often live with a fear of recurrence after ending active treatment."

RBC analyst Adnan Butt told Investors Business Daily that the results of the trial mean niraparib is “the PARP inhibitor to beat.” Other companies developing PARP inhibitors include Colorado-based Clovis Oncology and rucaparib, a PARP inhibitor developed for the treatment of patients with platinum-sensitive, high-grade serous or endometrioid epithelial ovarian, primary peritoneal or fallopian tube cancer.

The FDA accepted rucaparib for priority review in August. In September, the U.S. Food and Drug Administration (FDA) opted to not hold an advisory committee meeting to discuss rucaparib. Niraparib and rucaparib are possible contenders for AstraZeneca ’s Linparza, the first PARP inhibitor approved for women with BRCA-positive advanced ovarian cancer.

Tesaro is expected to file for approval with the U.S. FDA by the end of this year, with a final decision expected in 2017.

The continued successes of niraparib has caused speculation that Tesaro could be a takeover target. Companies that have been rumored to be interested in Tesaro include Gilead , Amgen , Celgene and Pfizer . Shares of Tesaro are trading at $117 as of 11:25 a.m.

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