Tesaro, Merck to conduct Phase I/II trial of Niraparib and Keytruda for breast and ovarian cancers

PARP, or poly (ADP-ribose) polymerase, is a DNA repair protein that restores single strand DNA breaks and by inhibiting PARP, certain cancer cells may be rendered unable to repair DNA damage, which can lead to cell death.

Tesaro’s niraparib is an oral, selective inhibitor of PARP-1 and PARP-2, while Keytruda is Merck’s anti-PD1 therapy.

The Phase I/II trial is designed to evaluate the preliminary safety and efficacy of niraparib plus Keytruda in these patients. It is expected to begin by the end of this year.

Tesaro president and chief operating officer Mary Lynne Hedley said: "The combination of a PARP inhibitor and anti-PD-1 antibody in this study has the potential to build upon the responses already observed with each of these compounds as monotherapies.

"Treatment options for patients with triple negative breast cancer are extremely limited, and we look forward to assessing this exciting new approach."

The company said that a Phase I/II monotherapy study of niraparib was completed in patients with advanced solid tumors.

Currently, two Phase III trials are being conducted to evaluate a single oral dose of niraparib as a maintenance therapy for patients with ovarian cancer (the NOVA study) and as a treatment for patients with BRCA-positive breast cancer (the BRAVO study).

Merck Research Laboratories oncology early stage development therapeutic area head and vice-president Dr Eric Rubin said: "We continue to expand the clinical development program for Keytruda across a range of cancers, both as monotherapy and in combination, and are delighted to add this new study to the more than 40 combination studies that are underway or planned with Keytruda."