Efficacy results were not uniformly positive in pivotal trials of newly approved perampanel, but FDA explains that may be due to high placebo rates in some international sites.

The late-stage pipeline for novel epilepsy treatments stars a handful of specialty and foreign firms, but the early-stage lineup makes room for new firms and the products of academic research. Venture philanthropy is a big factor, but the poor funding climate for CNS firms may limit play.

Proposed acquisition mimics other recent M&A deals, like Sanofi/Genzyme, with inclusion of contingent-value rights pegged to success of two clinical candidates.