18 Month Clinical Results Showed Significantly Slower Progression of Total Motor Score in RP103 Treated Patients Without Tetrabenazine Conference Call and Webcast Today at 8:30 a.m. EST NOVATO, Calif., Feb. 20, 2014 (GLOBE NEWSWIRE) -- Raptor Pharmaceutical Corp. (Nasdaq:RPTP) today announced top line results from a planned 18 month analysis of an ongoing 3 year Phase 2/3 clinical trial of RP103 (delayed-release cysteamine) for the potential treatment of Huntington's disease (HD) in collaboration with the Centre Hospitalier Universitaire d'Angers (CHU d'Angers). A total of 96 patients with HD were randomized to treatment with RP103 or placebo. Eighty nine patients completed the initial 18 month phase. Analysis of all 96 patients enrolled in the trial showed a positive trend towards slower progression of Total Motor Score (TMS) in patients treated with RP103 vs. those patients on placebo, the primary endpoint of the study. TMS progression was 32% slower in patients treated with RP103 vs. those treated with placebo after 18 months treatment (4.51 vs. 6.68 respectively, p=0.19). In 66 patients not taking concurrent tetrabenazine, RP103 treatment resulted in a statistically significant slower progression in TMS vs. the placebo group (2.84 points vs. 6.78 respectively, p=0.03). Due to the 36 month duration of the study, patients were allowed to continue their baseline medication regime, including antidepressants and tetrabenazine, the latter being an approved medication to treat chorea associated with HD. Patients were not randomized in the study based on concomitant medications. To confirm that the TMS results were not influenced by a potential treatment effect of tetrabenazine on chorea (a sub-score of TMS) the subset of patients not receiving tetrabenazine were analyzed for TMS. In these 66 patients (32 under placebo and 34 under RP103), RP103 treatment caused a statistically significant 58% slower progression in TMS of 2.84 points compared to 6.78 points for placebo (p=0.03) at 18 months. Slower progression was seen across all TMS sub-score measurements including eye and hand movements, balance and gait, as well as maximal dystonia and maximal chorea. Adverse events were similar in the two groups and were comparable to what has been observed in other studies in this patient population.