Actelion's selective S1P1 receptor agonist ponesimod to go into Phase III MS trial

Switzerland’s Actelion (SIX: ATLN) said this morning that the primary endpoint - reduction in the number of new active inflammatory lesions in the brain - has been met with its selective S1P1 receptor agonist, ponesimod, in a Phase IIb dose-finding study in patients with relapsing-remitting multiple sclerosis. As a result, the company, Europe’s largest biotech, said it will plant to move the drug into Phase III testing.

The study assessed efficacy, safety and tolerability of three ponesimod doses (10mg, 20mg or 40mg) versus placebo, administered orally once daily for 24 weeks. With 464 patients enrolled, this is the largest ever dose-finding study conducted in this autoimmune disorder of the central nervous system. In this study, ponesimod significantly reduced the cumulative number of new active lesions on monthly magnetic resonance imaging (MRI) brain scans performed from weeks 12 to 24, with the most effective dose at p<0.0001.

Martine Clozel, chief scientific officer at Actelion, commented: "This is the first report of a selective S1P1 receptor agonist reporting a statistically-significant treatment effect in patients suffering from relapsing multiple sclerosis. The relationship between lymphocyte count reduction and efficacy will be an important topic for further scientific scrutiny. The rapid reversibility of lymphocyte count observed upon treatment discontinuation already highlights a key differentiation attribute of this selective S1P1 receptor agonist and its pharmacokinetic profile."