Puma Biotechnology (PBYI) is pushing back an approval filing for its breast cancer drug neratinib into 2016 -- almost a one year delay -- because U.S. regulators have asked the company to compile and submit cancer-risk safety data from animal studies. Shares of Puma are down 19% to $182 in Tuesday's after-hours trading session following the company's announcement.
Neratinib is an oral inhibitor of the HER2 protein found in breast cancer. Puma is developing the drug as an "extended adjuvant treatment" following Roche's (RHHBY) Herceptin in patients with metastatic HER2-positive breast cancer.
Puma had expected to file neratinib with the FDA in the first half of 2015, but regulators have now asked for animal carcinogenicity data the company does not yet have. In order to fulfill the FDA's request, Puma now expects neratinib to be filed in the first quarter of 2016.
Most investors who own Puma believe founder and CEO Alan Auerbach will sell the company to Big Pharma. Auerbach sold his previous company, Cougar Biotechnology, to Johnson & Johnson (JNJ) , making his shareholders lots of money in the process. Many of these same investors are backing Auerbach again in Puma, believing he can pull off another big takeout. A delayed FDA filing -- and uncertainty about the outcome of the animal carcinogenicity studies -- may cause potential Puma suitors pause. Puma bulls are likely to argue that the neratinib filing delay just gives Auerbach more time to sell the company.