Receptos Inc (NASDAQ:RCPT) said the Phase 2 portion of the RADIANCE trial of its selective S1P1 receptor modulator, RPC1063, in relapsing multiple sclerosis (RMS) met the primary endpoint, reduction in MRI brain lesion activity. The overall safety profile of RPC1063 was consistent with the results of prior trials, and continues to support the differentiation of the drug candidate against other oral agents for treatment of RMS on the market or in clinical development. 

The randomized, double-blind study assessed the efficacy, safety and tolerability of two orally administered doses (0.5 mg and 1.0 mg) of RPC1063 against placebo in 258 patients with RMS across 77 sites in 13 countries. 

The primary endpoint of the trial was the reduction in the cumulative number of total gadolinium-enhancing (GdE) lesions determined by MRI from week 12 to week 24 of study treatment, a standard endpoint for Phase 2 trials in this indication. Patients on RPC1063 experienced a statistically significant reduction in GdE lesions of 86% at both 0.5 mg and 1.0 mg compared to patients on placebo (p-values <0.0001 for each dose group compared to placebo). Secondary endpoints measuring effects on other MRI parameters were also positive and statistically significant (p<0.0001 for each dose group compared to placebo).