GlaxoSmithKline has reported positive headline results from a Phase III trial of its Parkinson's disease candidate IPX066, which is partnered with Impax Pharmaceuticals.

The drug giant said that a 411-patient trial carried out by Impax showed that IPX066 - an investigational extended release form of carbidopa-levodopa - induced a 37% drop in off-time, (when a medication's affect has worn off), compared to a 17% decrease in patients taking an immediate release version of the active ingredient (IR CD-LD), moving the drug a step closer to approval.

IPX066 also demonstrated significant improvements over IR CD-LD in other endpoints, such as the Unified Parkinson’s Disease Rating Scale, Clinician Global Impression of Change and Patient Global Impression of Change, as well as on quality-of-life measures, the firm noted.

In further good news, the drug was also found to be generally well tolerated, with an adverse event rate of 43% compared to versus 40% for IR CD-LD during the double-blind portion of the trial, the most common being insomnia, nausea, fall, dizziness, and dyskinesia.

"Consistent with our Phase II findings, these data show IPX066 provides a robust level of efficacy across a range of PD clinical and QOL measures, which represents a potentially significant improvement over existing treatment options," said Suneel Gupta, Impax Pharmaceuticals' chief scientific officer, commenting on the findings.

Under the terms of the companies' development and commercialisation agreement sealed last December, Impax will complete the current Phase III programme for IPX066, and intends to file the drug with US regulators later this year. GSK holds an exclusive license to commercialise the drug around the globe except in the USA and Taiwan. 

Impax said it intends to present a full set of data at an upcoming scientific meeting, but shares in Impax had jumped more than 10% in after hours trading as investors welcomed the topline data.