Amgen notches positive PhIII results for top cancer drug

Dr. Sean Harper

Once again, Amgen's R&D chief Sean Harper has Roger Perlmutter to thank for a positive late-stage outcome on one of the Big Biotech's top cancer prospects. Before his departure from Amgen ($AMGN), Perlmutter--now head of R&D at Merck ($MRK)--had pushed AMG386 ahead in the clinic for ovarian cancer. And today Harper touted the news that the anti-angiogenesis drug, now dubbed trebananib, achieved promising top-line results from the first of three Phase III studies.

The primary goal of this study is progression-free survival. The drug arm, a combination of trebananib and paclitaxel, registered an average PFS of 7.2 months compared to 5.4 months for the control arm. That amounted to a 34% reduction in the risk of death.

So far so good, but the drug isn't out of the woods yet.

Overall survival remains a key objective, and Amgen noted that there was an "early imbalance of deaths favoring the control arm." That's an ominous sign, especially given the FDA's growing preference for a clear OS benefit ahead of an approval. A favorable trend was seen, though, and investigators expect to garner final OS data in 2014.

As TheStreet's Adam Feuerstein notes in his coverage of the story, Roche's Avastin has scored well on PFS, but can't get an approval for ovarian cancer as its studies haven't shown a survival benefit for patients. And even while the fight against ovarian cancer needs new medicines, the agency has been increasingly likely to demand hard OS results.

"It remains uncertain in our view, whether PFS benefit alone is sufficient for US FDA approval," noted RBC's Michael Yee. "At ASCO, AMGN mgmt stated OS benefit is most compelling (eg it's not clear to us whether they will even file for approval yet). AMGN might await OS maturity for filing and only 30% of the events have occurred. If approved, we believe AMG-386 could be a $300-500M product in recurrent ovarian cancer (first line study called TRINOVA 2/3 data readout not till 2015/2016)."

In another red flag, researchers also flagged the fact that 20% of the patients in the drug arm had to drop out due to side effects, compared to only 7% in the control arm. The anti-angiogenesis approach has been in play for years as researchers look for new and better ways to cut off the development of new blood vessels that feed tumor growth.

Roger Perlmutter

"The TRINOVA-1 study is the first of three Phase III trials designed to evaluate the safety and efficacy of trebananib in patients with ovarian cancer," said Dr. Sean Harper, executive vice president of R&D at Amgen. "Angiopoietin inhibition has been a focus of research at Amgen and these results suggest that the novel biology of trebananib may offer a promising approach for patients with ovarian cancer."

AMG386 was one of 8 late-stage programs in-house at Amgen when investors began to get anxious about the company's R&D costs. That anxiety helped cost Perlmutter his job after a number of others were cut as Amgen axed part of its R&D structure in an effort to rein in the research budget. But Amgen circled its wagons around the late-stage pipeline, setting up this positive outcome along with recent advances on its Phase III program for the oncolytic virus T-Vec--another one of Perlmutter's favorites.

- here's the press release
- here's the story from TheStreet

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