Consensus-beating sales for GW Pharmaceuticals’ lead product Epidiolex were not enough to impress investors, who sent the group’s stock down 16% today. The move could be explained by higher expectations on the buy-side than the sellside – the former had been looking for Epidiolex to bring in $90m in the third quarter, against the $86m reported, while the sellside had hoped for $85.5m. GW’s backers might also have been spooked by concerns that Epidiolex’s launch trajectory appears to be slowing already. The more generous might attribute a deceleration in new patient numbers to tough second-quarter comparisons, as patients have moved from receiving the drug for free under patient access schemes to being paying customers. These mitigating factors, however, will not play for too long. GW could soon have a rival in rare childhood epilepsies in the form of Zogenix’s Fintepla. So if the latest sales figures do not represent a move to a more sustainable ‘normal’, as claimed by GW’s management, and new growth levers like Epidiolex’s European and label extensions do not meet expectations, prepare for investors, if not sellside analysts, to carry on punishing the company.