GlaxoSmithKline (GSK) and Impax Pharmaceuticals have agreed to end their collaboration on the Parkinson’s disease drug IPX066.
The two companies blamed delays in the anticipated regulatory approval and, consequently, launch dates for the decision to end their 2010 agreement, which gave GSK the rights to develop and commercialise IPX066 outside the US and Taiwan for use in the treatment of symptoms of idiopathic Parkinson’s disease.
Impax will regain all rights to IPX066 in these regions, where it says it will attempt to find a partner that is looking to grow its non-US neurology franchise.
Neither company expanded on the reasons for the delays in regions covered by the agreement, but IPX066 has faced problems in the US where the FDA issued a complete response letter to Impax at the beginning of the year.
In the letter, the FDA said it was unable to complete Impax’ new drug application for IPX066 (under the brand name Rytary) as the regulator said it needed a “satisfactory re-inspection” of the company’s facility in Hayward, California, which is involved in the development, manufacture and distribution of the medicine.
The FDA issued a warning letter in 2011 noting several violations of good manufacturing practice regulations at the Hayward facility, including a failure to demonstrate an ability to control weight variations and support the necessary temperature change.
In an update on the Hayward facility published in March 2013, Impax said the FDA had completed a re-inspection, but had made 12 observations, including three that had previously been noted.
At the time, Dr Larry Hsu, president and CEO of Impax, said he was “clearly disappointed by the news”.
“Resolving the FDA concerns remains a top priority and we intend to complete this work as quickly as possible,” he added.
The decision to end the agreement with GSK is a further disappointment for Impax, although IPX066 could still have a future outside the US if the company finds another partner interested in a drug that has demonstrated superiority to the current standard treatment in advanced Parkinson’s patients experiencing motor fluctuations.