Puma Biotechnology, Inc. (PBYI) Down on Disappointing Drug Trials

Shares of Los Angeles, CA, based Puma Biotechnology, Inc. (PBYI) fell sharply on Tuesday, on a day that was mildly lower in stocks overall. Puma dropped $23.32 per share, down 13.72%, to close at 146.65 on volume of 3,602,943 shares. The stock continued to sell off following Monday's announcement by a cancer expert that the company's promising anti-cancer drug, neratinib, produces only very small improvements in breast cancer patients.

Founded in 2011, Puma Biotechnology, Inc. is a development stage biopharmaceutical company.
It acquires and develops innovative products for the treatment of various forms of cancer. The company focuses on in-licensing drug candidates that are undergoing or have already completed initial clinical testing for the treatment of cancer and then seeks to further develop those drug candidates for commercial use. The company's stock trades on the NYSE.

Puma's stock declined 9% on Monday, in reaction to comments by Dr. Harold Burstein, a breast cancer expert from the Dana-Farber Cancer Institute. Burstein reported that patients treated with Puma's drug, neratinib - in development for the treatment of HER2-positive breast cancer - showed only a very small improvement in their condition, compared with those in the placebo group. In addition, the drug produced grade 3 diarrhea in 40% of the patients who are on the drug therapy. Grade 3 diarrhea involves at least seven stools per day, incontinence, and even hospitalization.

The trials involved 2,840 patients who were treated with either neratinib, or with a placebo, for one year. Following the treatment, patients continued to be monitored for a recurrence of the disease for an additional year.

The report was the result of the neratinib Phase III "ExteNET study at the American Society of Clinical Oncology (ASCO). Test results showed that the absolute disease-free survival for patients treated with neratinib was 93.9%, compared to 91.6% for those in the group treated with a placebo. The difference between the two outcomes is just 2.3%. It is not clear if the benefit of the drug therapy outweighs the high incidence of grade 3 diarrhea.

In addition, the relatively short follow-up period of just two years is considered insufficient to prove the benefit of the drug with any degree of certainty. This could lead to the possibility that the FDA may ask for more data, further delaying the introduction of the drug to the market.

Puma executives see the outcome differently.

"We are very pleased with the results of the ExteNET trial with neratinib. This represents the first trial with a HER2 targeted agent that has shown a statistically significant benefit in the extended adjuvant setting, which we believe provides a meaningful point of differentiation for neratinib in the treatment of HER2 positive breast cancer... said Alan H. Auerbach, Chief Executive Officer and President of Puma. "We look forward to proceeding with the regulatory filing for neratinib for the extended adjuvant treatment of breast cancer currently anticipated in the first quarter of 2016.

Since neratinib is not expected to be available until next year, the company has another year to collect data on the patients that were part of the ExteNET study. The company also noted that the trials indicated that the incidence of grade 3 diarrhea could be substantially reduced in patients who are receiving preventative treatments.

Other News PBYI

Puma Bio Restricting Access to Breast Cancer Event at ASCO Chicago
Embroiled in controversy over its breast cancer drug neratinib, Puma turned away some investors and at least one analyst from the company's annual meeting of the American Society of Clinical Oncology on Monday.

Puma Crashes, Roche Rises On Cancer Data News
Prospects for neratinib were already shaky in mid-May.

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Published on Jun 3, 2015
By Kevin Mercadante

Copyrighted 2016. Content published with author's permission.

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