Puma Biotechnology (PUMA) shares ripped higher by 200% in after-hours trading on Tuesday with positive results from a late-stage trial of Puma’s experimental breast cancer drug, neratinib.
The ExteNET Trial met its primary endpoint, producing a 33% improvement in disease free survival compared to placebo, a hazard ratio 0.67 (p=0.0046). At the same time, the company announced an amendment to its licensing agreement with Pfizer (PFE) for neratinib (PB272), in which the smaller biotechnology company will take over additional R&D expenses form Pfizer ($30 million) and settled on paying the larger company a low- to mid-teens royalty rate on net sales of neratinib, the drug’s original developer.
Puma plans to file a New Drug Application for neratinib in 1H15.
The ExteNET trial tested neratinib in 2,821 patients with early-stage HER2-positive breast cancer who had undergone surgery and adjuvant treatment with trastuzumab. Patients were then randomized to receive further adjuvant treatment with either neratinib or placebo for 1 year. Patients were then followed for recurrent disease, ductal carcinoma in situ (DCIS), or death for a period of two years.
The secondary endpoint of the trial was disease free survival including ductal carcinoma in situ (DFS-DCIS). Treatment with neratinib resulted in a 37% improvement in DFS-DCIS versus placebo, a hazard ratio of 0.63 (p=0.0009).
Under the original license agreement, Puma was obligated to pay Pfizer annual royalties ranging between 10 and 20% of net sales of neratinib.
