Puma Biotechnology: Legacy Wyeth Study Provides The Back Story On Neratinib - Adjuvant Approval Appears Unlikely
- Based in part on data from a legacy Phase II study run by Wyeth in Herceptin pre-treated and naive patients, Neratinib unlikely to see approval in adjuvant HER2+ breast cancer.
- ~80% and 100% of Herceptin failures, including adjuvant stage patients, had progressed on Neratinib at 48 weeks and 96 weeks, raising doubts on Neratinib's efficacy over the long term.
- FDA unlikely to approve Neratinib on 2 years follow-up data. NDA filing will more than likely require 5-8 years of follow-up.
- In a 5-8 years follow-up of Neratinib in adjuvant disease, difference in disease-free survival between patients on Neratinib and patients on placebo unlikely to be statistically significant.
- Updating Price Target to $49.22/share to account for greater uncertainty associated with adjuvant Neratinib and to incorporate multiple expansion due to rally in biotech stocks. Reiterate Sell Rating.