Lynparza Vs. Niraparib

Shares of TESARO Inc TSRO fell more than 10 percent Tuesday after AstraZeneca plc (ADR) AZN presented better trial results for its ovarian cancer drug.

In a related development, shares of Clovis Oncology Inc CLVS gained more than 10 percent to set a new 52-week high of $68.58. Clovis’s PARP inhibitor Rucaparib is being studied for ovarian cancer.

The PARP inhibitors of Tesaro’s Niraparib and Astrazeneca’s Lynparza are fighting to gain market share in the oncology space. However, the positive data from Lynparza could hamper the commercial prospects of Niraparib and should support an approval in earlier lines of treatment for Lynparza.

Lynparza

In a late stage study, AstraZeneca’s Lynparza showed a significant improvement in progression-free survival (PFS) in germline BRCA-mutated (gBRCA) ovarian cancer patients. The trial met its primary endpoint of investigator assessed PFS of 19.1 months versus 5.5 months for placebo.

PFS as measured by Blinded Independent Central Review (BICR) evaluation, a pre-specified analysis supporting the primary endpoint, demonstrated a median PFS of 30.2 months versus 5.5 months for placebo, representing an improvement of 24.7 months.

Niraparib

On the other hand, Niraparib also reduced the risk of disease progression or death by 73 percent in patients with germline BRCA mutations (HR 0.27) and by 55 percent in patients without germline BRCA mutations (HR 0.45).

Tesaro claims Niraparib is the only PARP inhibitor that has shown a clinically meaningful increase in PFS in women with recurrent ovarian cancer, regardless of BRCA mutation or biomarker status.

Safety Profile

The most common grade 3/4 adverse reactions to Niraparib were thrombocytopenia (29 percent), anemia (25 percent), neutropenia (20 percent), and hypertension (9 percent).

On the other hand, nearly 37 percent of patients on Lynparza reported Grade 3 or higher adverse events, versus 18.2 percent of patients on placebo. The most common haematological adverse events reported in the Lynparza arm versus placebo were anaemia (43.6 percent), neutropenia (19.5 percent), and thrombocytopenia (13.8 percent).

Compared to Tesaro's Niraparib, Lynparza showed much lower rates of Grade 3 or higher neutropenia or thrombocytopenia events.

Regulatory applications are under review for Niraparib in the U.S. and Europe and TESARO expects to launch niraparib in the U.S. in the first half of 2017 and in Europe by year-end 2017, pending regulatory approvals.

Shares of Tesaro plunged 10.59 percent on Tuesday to close at $153.65. ADRs of Astrazeneca closed at $30.30, up 0.76 percent.

See Also:

Wedbush Cuts TESARO Target By 18% Following SOLO-2 Results

Clovis Reiterated As A Sell Following 10% Rally