In documents released Monday ahead of an FDA advisory panel meeting on May 24, agency reviewers concluded that the benefits of Puma Biotechnology's experimental therapy neratinib outweigh its risks for the extended adjuvant treatment of HER2-positive early stage breast cancer, sending shares in the drugmaker up as much as 80 percent. In the analysis, FDA staff found that the therapy was effective despite raising questions about its tolerability, given the frequent dose interruptions, reductions and discontinuations observed, mostly due to diarrhoea.
In the review, FDA staff found that neratinib was associated with a 2.8-percent improvement in invasive disease-free survival after two years. Meanwhile, the reviewers observed that nearly all patients in one study experienced any Grade diarrhoea, with 40 percent of patients experiencing Grade 3 diarrhoea. However, data from a second ongoing mid-stage trial indicate that antidiarrheal prophylaxis can lower both the incidence and severity of diarrhoea.
Puma submitted  a filing to the FDA last year seeking approval of neratinib after delaying  submission of the therapy due to the agency requesting changes to data analysis. Neratinib was accepted for review by the FDA in September 2016.
For related analysis, see ViewPoints: Puma's day at the FDA nears – how many lives has this cat got?