NEW YORK (AP) — Impax Laboratories Inc. and GlaxoSmithKline PLC said Monday that their extended-release experimental drug for Parkinson's disease met its main goal in a late-stage study.
Shares of Impax rose $1.83, or 10.9 percent, to $18.63 in morning trading.
The clinical trial measured the effectiveness of IPX066, which is designed to be a longer-lasting version of a common treatment for the physical symptoms of Parkinson's disease. The study compared the new formulation to the standard form of the drugs carbidopa and levodopa.
Impax and GlaxoSmithKline said patients treated with the drug had significantly less "off time," or waking time when their medication wore off and the motor symptoms of Parkinson's disease returned.
The companies said patients treated with the new formulation had 3.8 hours of "off time" per day, on average, while patients treated with the original forms of carbidopa and levodopa averaged 5.2 hours. Patients started the study with an average of 5.9 hours of "off time."
Parkinson's disease is a degenerative illness that causes problems including tremors, rigidity and slow movements.
Impax and GlaxoSmithKline said 84 patients completed the study. The most common side effects of treatment with IPX066 were insomnia, confusion, and sudden, uncontrollable muscle movements. Those side effects were observed in three patients each. The most common side effect of the carbidopa-levodopa regimen was falling, which affected two patients.
The companies said 20 percent of IPX066 patients had side effects, compared with 14 percent of patients treated with the older drugs. Two serious side effects, sciatica and dehydration, were seen in IPX066 patients. None were observed in the carbidopa-levodopa group.
Carbidopa and levodopa are marketed as a combination drug under several names, including Sinemet.
The companies are running three late-stage studies of IPX066. Impax, of Hayward, Calif., said it plans to file for U.S. approval of the drug during the fourth quarter, and it intends to present full results from Monday's study at a future scientific meeting.
GlaxoSmithKline, which is based in London, will file for approval in European Union in 2012. Glaxo has full rights to develop and sell the drug in all countries except the U.S. and Taiwan.
GlaxoSmithKline stock gained 60 cents to $41.90.