PBYI Soars on Positive Neratinib Data

Shares of Puma Biotechnology, Inc. (PBYI) soared over 68% on Dec 5 to end the day’s trading at $77.70. The stock also touched a 52-week high of $80.77 during the course of the trading session on that day.

Shares of Puma Biotech were boosted by positive top-line results from a phase II I-SPY 2 (Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging And moLecular Analysis 2) study on its lead oncology candidate, neratinib (PB272).

Puma Biotech is evaluating the candidate in patients who were newly diagnosed with stage 2 or higher (tumor size at least 2.5 cm) breast cancer. Results from the study showed that a higher pathological complete response (pCR) rate was observed in the neratinib-containing regimen compared to the control arm, standard neoadjuvant chemotherapy. The standard neoadjuvant chemotherapy consists of Taxol (paclitaxel) in combination with Herceptin followed by Doxil (doxorubicin) and Cytoxan (cyclophosphamide).

Results further revealed that the neratinib arm demonstrated a 94.7% probability of superiority in comparison to standard therapy (according to Bayesian predictive model). Puma Biotech further mentioned that the Bayesian predictive probability was also statistically superior in the neratinib plus Taxol regimen compared to the Taxol plus Herceptin regimen in a separate randomized phase III study (n=300).

With the positive results from the SPY 2 study, neratinib is now eligible for the upcoming I-SPY 3 phase III study. Puma Biotech expects to move the neratinib-containing regimen in to a phase III study in the neoadjuvant setting.

Neratinib is being studied in other forms of cancer as well. We note that Puma Biotech has a worldwide exclusive license agreement with Pfizer Inc. (PFE) for neratinib. We expect investor focus to remain on neratinib going forward.

Although the company is progressing well with its pipeline, we remind investors that the oncology market currently has companies like Roche (RHHBY).

Puma Biotech carries a Zacks Rank #3 (Hold). Some better ranked stocks include Zacks Ranked #1 (Strong Buy) Actelion Ltd (ALIOF).

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