Amgen to pursue T-Vec approval despite PhIII survival miss

CHICAGO--Back in April, Amgen's ($AMGN) cancer-fighting viral vaccine stumbled in Phase III, missing on overall survival (OS), a secondary endpoint. But that won't stop the California company from seeking regulatory approval, it announced early this week.

Amgen R&D chief Sean Harper

Amgen will push forward with a filing package for the candidate, talimogene laherparepvec--also known as T-Vec--this year as a monotherapy in metastatic melanoma, eyeing a U.S. application in the short term but looking outside the U.S. as well.

As R&D Chief Sean Harper said in a statement, T-Vec "has demonstrated the ability to produce durable and complete responses in patients with metastatic melanoma which provides a strong basis for a filing later this year and potential approval of talimogene laherparepvec as a novel treatment for this devastating disease."

Despite falling just short of statistical significance in OS, T-Vec did increase the median OS rate to 4.4 months and also hit the study's primary endpoint with a 16% durable response rate.

"We're enthusiastic about this data package," David Reese, Amgen's VP of translational sciences, told FierceVaccines.

T-Vec might also have a future as a partner in immunotherapy duos, a Phase Ib study showed. In that trial, T-Vec administered prior to or in combination with Bristol Myers-Squibb's ($BMY) Yervoy either shrank or eliminated tumors in 56% of the 19 participating patients. Importantly, researchers didn't find that use of the pair enhanced toxicity--one of the key challenges with immunotherapy combos.

Because of T-Vec's relatively favorable adverse event profile, Reese said the company thinks T-Vec could eventually be a partner for a number of other immunotherapies. "Those are things we're exploring quite actively," he said.

For starters, this year the company will begin testing the vaccine--intended to stimulate the immune system--with Merck's ($MRK) highly anticipated PD-1 candidate, a checkpoint inhibitor designed to take off the immune system's brakes. "You have this really complementary biologic approach," Reese said.

While the early combination data looked promising, that doesn't mean the company is casting aside T-Vec's potential as a monotherapy. The OS data may have lowered some analysts' hopes for future sales, but in addition to seeking approval in melanoma, Amgen said it would also be exploring T-Vec with other tumor types.

"It's our belief that T-Vec may have a role in both arenas," Reese said.

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Special Report: Top 10 experimental cancer drugs - 2013 - T-Vec