Clovis Wins One ASCO '15 Battle, Loses Another, Against Rival AstraZeneca

CHICAGO (The Street) -- It seems impossible to invest in, think about (or write on) Clovis Oncology (CLVS) without first considering the heated, multi-front competitive battle with AstraZeneca (AZN). This weekend's ASCO annual meeting was no different.

Clovis' rucaparib made a strong claim Saturday to unseat AstraZeneca's Lynparza as the most effective PARP inhibitor treatment for a genetically defined segment of previously-treated ovarian cancer patients.

But AstraZeneca fought back Sunday when a highly anticipated presentation of Clovis' lung cancer drug rociletinib produced mediocre results. AstraZeneca's lung cancer drug AZD9291 appears superior.

Clovis shares closed Friday at $92.44, but the stock could fall Monday given lung cancer data at ASCO acknowledged as "disappointing" by one one sell-side analyst with a history of being very bullish about the company.

In a mid-stage study of patients with advanced ovarian cancer carrying the mutated BRCA gene, treatment with Clovis' rucaparib yielded a response rate of 82%. Ten percent of patients had complete resolution of their tumors. Median progression-free survival was 9.4 months.

Another 45% of ovarian cancer patients with "BRCA-like" mutations responded to rucaparib. Median progression-free survival in these patients was 7.1 months.

Mid-stage studies of rucaparib are still ongoing, but Clovis set plans to seek regulatory approval for rucaparib next year. The company estimates 25% of ovarian cancer patients carry the BRCA mutation, with another 35% of patients carrying "BRCA like" mutations also amenable to treatment with rucaparib.

AstraZeneca secured accelerated approval for Lynparza in the U.S. last December based on a 34% response rate and a median progression-free survival of 7.9 months in women with BRCA-mutated ovarian cancer. Both Lynparza and rucaparib work by blocking a protein, PARP, used by tumors to heal themselves, however Clovis believes rucaparib could be approved to treat the larger swath of patients with BRCA and BRCA-like mutations.

Clovis' targeted lung cancer drug rociletinib didn't fare as well during a Sunday presentation. Updated results from a mid-stage study showed a median progression-free survival of eight months, lower than the 10-month progression delay reported previously. Response rate to rociletinib was 60%.

Earlier this spring, AstraZeneca reported a median progression-free survival of 13.5 months in lung cancer patients treated with AZD9291.

Both drugs have safety concerns to tend with. Clovis' rociletinib causes a significant number of patients to suffer from high blood sugar, which in some cases must be controlled with oral diabetes drugs. AstraZeneca's AZD9291 is linked to serious cases of interstitial lung disease, including deaths.

Both Clovis' rociletinib and AstraZeneca's AZD9291 are designed to be effective against non-small cell lung cancer containing a genetic mutation known as T790M, which renders tumors resistant to treatment with drugs like Roche's Tarceva.

Clovis and AstraZeneca are each expected to seek regulatory approval for their respective lung cancers drugs later this year.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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