Puma Biotech leaps on supplemental label for Nerlynx

Following the news that the US Food and Drug Administration had approved a labeling supplement for Nerlynx (neratinib) for the extended adjuvant treatment of HER2-positive early stage breast cancer, shares of Puma Biotechnology (Nasdaq: PBYI) shot up 13% in after-hours trading on Wednesday.

With the approval of the labeling supplement, the label now includes safety information based on interim results from Puma’s Phase II CONTROL Trial, a study evaluating antidiarrheal prophylaxis or dose escalation in the reduction of neratinib-associated diarrhea that has a primary endpoint of the incidence of grade 3 or higher diarrhea. Interim data from the trial showed that the addition of prophylactic treatment with loperamide plus budesonide reduced the discontinuation rate due to neratinib-associated diarrhea to 11% versus a discontinuation rate of 18% with loperamide alone.

In the ongoing CONTROL Trial, patients with HER2-positive early stage breast cancer who have completed trastuzumab-based adjuvant therapy receive neratinib daily for a period of one year. The trial initially tested high dose loperamide prophylaxis given for the first two cycles (56 days) of treatment (12mg on days 1-14, 8mg on days 15-56 and as needed thereafter). The CONTROL Trial (NCT02400476) was then expanded to include four additional cohorts. One cohort received the combination of loperamide and budesonide. For the 64 patients who received the combination of loperamide plus budesonide, the incidence of grade 3 diarrhea was 28% compared to 32% in patients treated with loperamide alone. Diarrhea leading to treatment discontinuation declined to 11% in the loperamide plus budesonide cohort, compared to 18% in the loperamide alone cohort.