Puma gets adcomm OK ahead of FDA decision
- L.A. biotech company Puma Biotechnology has gotten a thumb's up from the Food and Drug Administration's Oncologic Drugs Advisory Committee (ODAC) with a 12 to 4 vote to recommend approval of PB272 (neratinib) for the extended adjuvant treatment of HER2-positive early stage breast cancer.
- The ODAC decision is not binding, but is often followed by the FDA when considering approval of drugs. Despite the positive decision, there are still questions about the rate of efficacy for the drug and a high rate of diarrhea seen in patients.
- The company's shares surged for the second time this week – they were up 40% on the release of the preliminary documents and then 30% on the ODAC response, and an overall increase of more than 130% over the last week to trade near $79 per share.
The new drug application for Puma Biotechnology's lead product candidate, neratinib, was accepted for review by the FDA in September 2016 to reduce the risk of breast cancer recurrence in post-surgery patients with early stage HER2-overexpressed/amplified disease who have received prior adjuvant Herceptin (trastuzumab)-based therapy.
The FDA is expected to make decision on approval of neratinib by July 21.
There have been doubts raised about neratinib's pivotal study. The ExteNET study, which lasted eight years, went through a number of protocol changes, leading to questions about its statistical significance. And the drug, which is designed to be taken by otherwise healthy women, causes diarrhea in the vast majority of users, becoming severe in around four in 10.
In the ODAC meeting, discussions mostly centered around these two topics. Concerns were raised about the levels and severity of diarrhea, and Puma stated that the diarrhea was transient, generally occurring within the first eight days of treatment and not recurring, and manageable with anti-diarrheal prophylaxis.
The trial hasn't yet been running long enough to see the drug's impact on overall survival, and through this isn’t an FDA requirement, Richard Pazdur, director of the FDA's Oncology Center of Excellence (OCE), has said that they will look into this to make sure that there is no detriment in overall survival.
While the votes were positive overall, there were calls for a more limited indication, from both the yes and the no voters, with concerns that the data was too limited, and that this could be a route into using the drug in metastatic disease.
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