Tesaro shares skid lower as AstraZeneca wows with PhIII data on PARP drug for ovarian cancer

AstraZeneca spelled out its impressive Phase III data for Lynparza (olaparib) pills, which will now line up against Tesaro’s rival PARP niraparib.

Pascal Soriot

In a central, blinded review the drug achieved a median progression-free survival rate of 30.2 months in germline BRCA-mutated, platinum-sensitive, relapsed ovarian cancer patients versus 5.5 months for the placebo arm. A solid success for AstraZeneca, which badly needs to continue to build up its oncology group if CEO Pascal Soriot expects to achieve anything like the big turnaround he’s been promising investors for years.

The drug also achieved a statistically significant result in delaying the second progression or time to death, with the median rate not reached for Lynparza compared to 18.4 months for placebo.

AstraZeneca got a jump on the PARP market with shaky early data, which reined in its revenue potential. The pharma giant earned only a bit more than $200 million on Lynparza last year, but expects to increase that past the $1 billion blockbuster mark as it looks to broaden its use as a maintenance therapy in the US.

Tesaro $TSRO has been aiming at a direct showdown with AstraZeneca as it winds up for a likely near-term approval on niraparib. Its reduction in risk compares closely to olaparib, with a PFS rate that won’t look as good.

Tesaro’s niraparib data highlighted a clear impact for the targeted drug in a population of germline BRCA mutation carriers, with a median PFS of 21 months in the drug group compared to 5.5 months in the control arm — a 15.5-month advantage that will not compare well with Lynparza’s, which beat placebo by slightly more than two years.

Sean Bohen

Tesaro’s shares skidded down 12.5% on the comparison. Clovis $CLVS, meanwhile, which has had problems of its own in developing its newly approved PARP Rubraca, saw its shares rise 6.9% as the horse race among all the PARPs looked tighter than ever.

Pfizer will look to join this group in the not too distant future with its own pivotal data for a PARP — talazoparib — picked up in the $14 billion Medivation acquisition.

“With these data, we believe it is very difficult to challenge the notion that the leading PARPs (niraparib, olaparib, rucaparib, talazoparib) are more similar than different,” summed up Leerink’s Seamus Fernandez. “But following our conversation with AZN, they are most focused on the safety and tolerability of olaparib, which they believe is a key area of differentiation vs. niraparib.”

AstraZeneca R&D chief Sean Bohen said:

We are extremely pleased with the results from SOLO-2, which support the potential benefit of LYNPARZA tablets as a maintenance therapy for patients with relapsed ovarian cancer. The tablet formulation may offer patients a reduced pill burden for LYNPARZA and a safety profile that is generally consistent with previous trials. We will work with regulatory authorities to make LYNPARZA tablets available to patients as quickly as possible.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
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Atlas Venture Cambridge, MA

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