Cephalon, Inc. has signed an agreement to acquire the North American rights to Amrix (cyclobenzaprine hydrochloride extended-release capsules) from ECR Pharmaceuticals for $100 million cash. ECR is eligible to receive future cash payments based on the achievement of certain milestones.

The FDA approved two dosage strengths of Amrix (15 mg and 30 mg) in February 2007 for short-term use as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute, painful musculoskeletal conditions. Cephalon expects to launch the product in the U.S. early in the fourth quarter.

“Amrix is an excellent strategic fit with our current sales organization, providing us with a second product that is complementary to many pain relievers used today,” said Robert Roche, executive vice president, Worldwide Pharmaceutical Operations. “Cyclobenzaprine HCl is the most widely prescribed muscle relaxant in the U.S., representing 37% of the 45 million prescriptions for muscle relaxants written in 2006, according to IMS. Amrix has convenient once-daily dosing and a side effect profile that includes very low rates of sedation which will provide physicians and patients an attractive alternative to current therapies.”