GW Pharmaceuticals is selling its rare paediatric disease priority review voucher (PRV) for $105 million to Biohaven Pharmaceutical.

The voucher, which entitles the holder to a six-month speedy review of a marketing application, was issued under a US Food and Drug Administration (FDA) programme designed to incentivise the development of treatments for rare paediatric diseases.

GW Research received the PRV when its cannabinoid medicine Epidiolex was approved by the FDA for the treatment of seizures associated with Lennox-Gastaut Syndrome or Dravet syndrome, two rare, severe childhood-onset epilepsies.

The sale of the voucher remains subject to customary closing conditions, including anti-trust review.

"The sale of the PRV provides an important source of non-dilutive capital to help advance our pipeline and to continue to invest in the Epidiolex commercial launch in both the US and Europe," stated Justin Gover, GW's chief executive, explaining the reason for the move.

Biohaven said it intends to use the voucher to accelerate the regulatory review of its US marketing application for migraine drug Zydis (rimegepant).