Actelion says that it is on the verge of putting its investigative oral  multiple sclerosis drug ponesimod into Phase III following promising mid-stage data.

The Swiss biotech said the primary endpoint, ie reduction in the number of new active inflammatory lesions in the brain, has been met with ponesimod in a Phase IIb study in patients with relapsing-remitting MS. The study looked at three doses (10 mg, 20 mg or 40 mg) versus placebo, administered orally once-daily for 24 weeks.

The company noted that despite the small overall number of confirmed relapses, there was also a clinically meaningful effect observed on annualised relapse rate, "an important secondary endpoint". Actelion added that the adverse events seen in the study "would give ponesimod a competitive safety and tolerability profile".

Chief scientic officer Martine Clozel noted that "this is the first report of a selective S1P1 receptor agonist reporting a statistically significant treatment effect in patients suffering from relapsing MS, saying that "the relationship between lymphocyte count reduction and efficacy will be an important topic for further scientific scrutiny". Guy Braunstein, head of clinical development, said the data "gives us confidence that we can identify the appropriate dosing regimen for the upcoming Phase III programme".

The data has gone down well with observers who frequently voice their concerns over Actelion's reliance on the pulmonary arterial hypertension blockbusterTracleer (bosentan). However, if approved, ponesimod would be entering the market well behind Novartis' already-approved MS pill Gilenya (fingolimod), Biogen Idec's BG-12 (dimethyl fumarate) and Teva/Active Biotech's laquinimod.

Analysts at Jefferies issued a research note saying that ponesimod is theoretically a more selective drug than Gilenya. However they believe Actelion will partner the drug shortly, given its "relative inexperience conducting large pivotal CNS trials and finite financial resources.