May 23, 2017
By Alex Keown, BioSpace.com Breaking News Staff
LOS ANGELES – Shares of Puma Biotechnology are up more than 35 percent after the company announced the U.S. Food and Drug Administration announced it will review the company’s breast cancer drug, PB272 (neratinib) this week.
On Monday, Puma said the FDA posted briefing documents for PB272 on its website in preparation for the May 24 Oncologic Drugs Advisory Committee (ODAC) meeting. The committee is an independent panel of experts that evaluates data concerning the efficacy and safety of experimental treatments and makes recommendations to the FDA. Those recommendations are not binding, but the FDA does take the ODAC information into consideration before ruling.
PB272 is being developed for the extended adjuvant treatment of HER2-positive breast cancer. PB272 is a potent irreversible tyrosine kinase inhibitor, for the treatment of patients with HER2-positive breast cancer and patients with non-small cell lung cancer, breast cancer and other solid tumors that have a HER2 mutation. HER2-positive breast cancer is an aggressive form of the disease, which affects approximately one in five people with breast cancer and is associated with a poor prognosis if left untreated.
Extended adjuvant treatment for breast cancer is important, as about one-third of people treated with a drug like Roche’s Herceptin and chemotherapy may eventually see their cancer return.
Since Puma made the announcement on Monday, share prices have climbed from $39 to a high of $58.17 this morning. While that’s a considerable jump, Forbes’ Matthew Herper warns that before pulling the trigger on buying shares, there are some potential “deal-killers” regarding the drug. In his column, Herper said PB272 is being developed for patients who have already had breast cancer surgically removed and undergone treatment with Roche’s Herceptin to keep the disease from coming back. PB272 would be added to the regimen to further reduce the rate of breast cancer recurrence.
Puma initially submitted its New Drug Application for neratinib to the U.S. Food and Drug Administration in July. The NDA was submitted following a successful Phase III trial that demonstrated treatment with neratinib resulted in a 33 percent reduction of risk of invasive disease recurrence or death versus placebo. In clinical trials, PB272 demonstrated a disease-free survival (DFS) rate of 93.9 percent compared with 91.6 percent in the placebo group. The FDA did request an additional statistical analysis of the trial data, which delayed the company’s regulatory approval timeline. Resubmitted data showed DFS rates were 94.2 percent and 91.9 percent for neratinib and placebo, respectively, which was not a dramatic improvement.
Additionally, PB272 has another issue that regulators will look at – severe diarrhea. Approximately 40 percent of patients who took the drug suffered a severe form of diarrhea, although about 95 percent of patients who took the drug had some form of diarrhea. Incidents of grade 3 diarrhea were single-episode events, with episodes restricted to the first cycle of therapy.
Diarrhea has long been associated with chemotherapy due to the effect the drug has on healthy cells in the digestive tract. Grade 3 diarrhea is defined as an “increase of seven stools per day, plus incontinence.”
While Puma shares are up this morning, another adjuvant treatment for breast cancer will also soon be up for review – Roche’s Perjeta. In March, Roche and its subsidiary Genentech announced positive results from its Phase III combination study of Perjeta, Herceptin and chemotherapy showed a statistically significant reduction in tumors returning or death.
