Inhaled migraine drug VR147 shows early promise

The traditional oral and injection-based delivery routes for migraine therapies are associated with various shortcomings, ranging from a delayed onset of action to the requirement for administration by a healthcare professional. As a result, Vectura and US rivals such as MAP Pharmaceuticals and Alexza are developing inhalable solutions for the lucrative migraine treatment market. Additionally, with US patent protection for GlaxoSmithKline's drug Imitrex (sumatriptan succinate) set to expire in 2009 and an increasing number of products becoming available over the counter, the market potential for novel drugs with improved delivery methods could increase dramatically. Triptans worth $2.3bn a year ​ At present, the migraine market is dominated by a class of drugs known as the triptans, which achieved annual sales of around $2.3bn (€1.5bn) in 2007. While such agents provide relief from acute attacks, they have a slow onset of action, often taking between 40 and 90 minutes to reduce symptoms. Additionally, the artierial constriction that triptans induce has been associated with an increase in blood pressure, meaning that they are not always suitable for patients suffering from circulatory problems. Although VR147 is a triptan, the new results indicate that because it is delivered via inhalation it achieves a maximum arterial plasma concentration around four minutes after administration. The study also showed that, in comparison with a subcutaneous administration of the drug's active component, VR147 reduces the time to maximum veneous plasma concentration by around a third to eight minutes. Vectura also reported that VR147 had a favourable adverse event profile that was consistent with the active ingredient, and added that no abnormal changes in electrocardiogram readings had been observed in those taking part in the study. Chris Blackwell, Vectura's chief executive, said that the data provided the firm with an opportunity to create value in a very significant market. Blackwell explained that: "the primary need of migraine patients is to obtain rapid onset of relief, and there is evidence to suggest that this can also have a positive impact on severity​." He added that Vectura will use the promising early data to examine licensing opportunities for both VR147 and the inhalation technology that on which it is based. Potential competition from MAP ​​While in the majority of cases triptan is effective, around 30 to 40 per cent of patients fail to respond to treatment. For such individuals the drug dihydroergotamine is often employed as an alternative. However, while dihydroergotamine overcomes some of the problems associated with triptans, it has a more rapid onset of action, it usually requires intravenous administration by a healthcare professional and, as such, is a more expensive therapeutic option. In an effort to capitalize on this market opportunity, MAP pharmaceuticals is developing a formulation of dihydroergotamine in conjunction with its proprietary Tempo inhalation system. In its most recent update, MAP said that it intends to move MAP0004 into Phase III testing in the next few months.