FDA approval is always welcome news, especially to patients needing treatment and stockholders waiting patiently for a return. GlaxoSmithKline and Xenoport announced today that the FDA has approved its Horizant new drug for postherpetic neuralgia (PHN) in adults.
The drug, known pharmaceutically as gabapentin enacarbil, is given as extended release tablets for the painf that occurs as a complication of shingles and affects the nerve fibres and skin.
Shingles could be termed as the adult version of the childhood disease chicken pox. The virus, known as herpes zoster, causes a painful blistering skin rash. Whilst anyone can catch it, those not having had chicken pox or vaccines as children and those over the age of 60 are most at risk, and while it usually clears up within a few weeks, the pain and discomfort of postherpetic neuralgia can last months or even years.
Three clinical studies of Horizant involved 574 adult patients from the US, Canada and Germany. The effectiveness and safety of Horizant for the management of PHN was evaluated in a single 12-week principal efficacy trial, plus two supportive studies that all met their respective primary endpoints.
Patients generally take 600mg twice daily, although doses can be adjusted for those with reduced renal function. During the 12 week trial, some 10% of patients complained of somnolence (sleepiness or drowsiness), but interestingly 8% of those on the placebo also complained of the same thing. Dizziness was reported in 17% of patients receiving the 1200mg of Horizant per day compared with 15% on the placebo. Perhaps those symptoms are common in patients with postherpetic neuralgia.
The Glaxo press release doesn't say what the success rate of the drug is and calls to the media office were not answered. The drug was originally discovered by Xenoport who will receive a $10M milestone payment from Glaxo when the first commercial sale of the drug is made. The drug is also marketed for restless leg syndrome under the brand name Regnite.
XenoPort is developing other drugs for neurological disorders, including neuropathic pain, spasticity, and Parkinson disease. The firm's arbaclofen placarbil candidate is in Phase III development for the treatment of spasticity, and the levodopa prodrug XP21279 has completed Phase II studies as a potential treatment for Parkinson disease. Arbaclofen placarbil is a drug that is converted in vivo to the R-isomer of the selective GABA-B agonist baclofen.
Written by Rupert Shepherd
View drug information on Horizant.
Copyright: Medical News Today
