Raptor Pharmaceuticals Corp. (RPTP) soared almost 14.9% after the company announced encouraging top-line results from an 18-month analysis of an ongoing phase II/III study (n=96) on RP103. Raptor is developing the candidate for the treatment of Huntington's disease in collaboration with the Centre Hospitalier Universitaire d'Angers (CHU d'Angers).
The study spanning 36 months was divided into two 18-month parts. The first part was a double-blind, placebo-controlled phase while the next part was an open label phase when all patients transitioned to RP103 treatment. Raptor stated that 89 patients completed the initial part of the study while 7 patients discontinued treatment.
Results from the first 18-month analysis showed that total motor score (:TMS) in patients treated with RP103 was 32% slower than those under placebo. The change in the TMS sub-scale of the Unified Huntington Disease Rating Scale (:UHDRS) from baseline after 18 months of treatment, in the placebo and RP103 arms, was the primary objective of the study.
The progression of TMS was however slowed down in patients who were not receiving treatment with Valeant Pharmaceuticals International, Inc.’s (VRX) Xenazine (tetrabenazine). Xenazine is approved for the treatment of Huntington's disease, for the chorea associated with the condition, which is a component of TMS. Raptor further stated that slower progression was observed in all TMS sub-score measurements. The initial phase of the study also proved that RP103 was more safe and well tolerated compared to placebo.
Raptor intends to file for an orphan drug designation in the EU for RP103, which was earlier declined on grounds of absence of clinical data. The candidate however enjoys an orphan drug status in the U.S. We are encouraged by the positive top-line results from the initial phase of the study. We expect investor focus to stay on the second portion of the phase II/III study on RP103.
Raptor Pharma, a biopharmaceutical company, currently carries a Zacks Rank #3 (Hold). Some better-ranked stocks in the same sector include Alexion Pharmaceuticals, Inc. (ALXN) and Actelion Ltd. (ALIOF). While Alexion holds a Zacks Rank #1 (Strong Buy), Actelion carries a Zacks Rank #2 (Buy).