Impax Pharmaceuticals and partner GlaxoSmithKline (GSK) reported positive topline data from the Phase III Ascend-PD study comparing the extended-release carbidopa-levodopa drug candidate, IPX066, with carbidopa- levodopa plus entacapone (CLE) in patients with advanced Parkinson disease. The trial met its primary endpoint, in terms of reducing percentage off time during waking hours. Off time, recorded by the patient, represent the functional state when medication effects have worn off and there is a return of the motor symptoms of PD.
Results from the Phase III Ascend-PD study, which was completed by 84 subjects, showed that treatment with IPX-066 reduced off time from a baseline of 5.9 hours (36.1%) to 3.8 hours (24%), whereas treatment with CLE reduced off time during waking hours by less than an hour, to 5.2 hours (32.5%). The figures equated to IPX066 reducing off time by 33.5% from baseline compared and CLE therapy reducing off time by just 10%.
The Ascend-DP data support those from the recently completed Advance-PD study, which compared extended-release IPX066 with immediate-release carbidopa-levodopa (CD-LD). Data from Ascend-DP were announced in May. Positive topline results from the Phase III placebo-controlled Apex-PD study evaluating IPX066 in early Parkinson disease patients were reported in November 2010.
Impax says it aims to submit an NDA for IPX066 to FDA by the end of 2011. GSK expects to file a marketing authorization application for IPX066 in the EU during 2012. The firms inked their IPX066 development and commercialization deal in December 2010. Under terms of the agreement, GSK has an exclusive license to register and commercialize the drug worldwide, excluding the U.S. and Taiwan. Impax received an $11.5 million up-front payment from its partner and could earn up to $175 million in development and commercialization milestones, plus additional tiered, double-digit sales royalties.
IPX066 is Impax’ lead compound. The firm aims to build a pipeline of improved versions of existing CNS drugs that demonstrate enhanced efficacy, safety, and patient compliance. Target diseases associated with movement disorders include restless legs syndrome, spasticity, and epilepsy.