MHRA technology assessment slows approval of GW Pharmaceutical's Sativex

UK-based GW Pharmaceuticals has withdrawn its EU application for Sativex, following demands by UK regulators for additional data in support of the MS and cancer pain treatment.

GW says that there are no quality or safety issues attached to Sativex, but rather that the Medicines and Healthcare products Regulatory Agency (MHRA) requested that the company produce data on specific patients who respond to the treatment.

The halt in the approval process was initiated by the fact that Sativex is intended for patients who have exhausted all other treatment options, which means that some subjects simply lack the ability to respond to the the drug, or any other MS treatment.

The MHRA asked GW to conduct confirmatory studies examining patients which show a response to Sativex, and to identify the level in response in this set of subjects.  

This demand was made despite the fact that GW performed analysis of existing data through which responders were found to be easily identifiable, as well as 62 per cent more likely to achieve a meaningful response than on placebo.

The new data is demanded from a purely technical point of view and the MHRA has asked that analyses be carried out in a prospective way rather than in a post-hoc' manner, which is effectively a more focused Health Technology Assessment (HTA).

GW said that this type of study was due to happen later in the drug's approval process, and it says it already has designs for a confirmatory study in place.  The first patients are due to join the trial in October 2007 and should complete within a year.

A second pivotal phase III trial of Sativex for the treatment of MS neuropathic pain is due to complete in Q1 2008, which could lead to a regulatory filing at the same time.  As the outstanding issue regarding efficacy in responders relates to an indication of MS spasticity, it should not affect the pain application, says GW.

GW has also received approval for Sativex in Canada, for use as an adjunctive therapy for the relief of neuropathic pain in patients with MS. The company also expects Canadian approval for the relief of cancer pain in the near future.

In the US, cancer pain is the lead indication for Sativex, with the first patients entering pivotal late stage trials next month.

GW has licensed Sativex to Bayer Healthcare for the Canadian and UK markets and Almirall Prodesfarma for the rest of the EU. The most important agreement is with privately owned Japanese pharmaceutical company Otsuka for the US and other global markets.

In total, the agreements to date have made GW a total of USD 51m (EUR 37m) in signature fees, as well as approximately USD 376m in milestone payments, and long-term supply price deals.