Merck & Co has returned the global marketing and development rights to Cardiome Pharma Corp for both the intravenous and oral formulations for the anti-arrhythmic vernakalant.

The drugs giant has been marketing the intravenous form of the drug, as Brinavess, in the European Union and Latin America for the rapid conversion of recent onset atrial fibrillation and was looking to launch the product in 30 additional countries this year. However, Michael Mendelsohn, head of atherosclerosis and cardiovascular research at Merck Research Laboratories, said "we have made a business decision" to return the rights.

The move is not particularly surprising given that in March, Merck decided to discontinue further development of the oral formulation of vernakalant. That decision was based on "an assessment of the regulatory environment and projected development timeline", the company said at the time and Cardiome's shares sank. The Canadian firm was then forced to slash 85% of its workforce, eliminating all positions focused on internal research.

Dr Mendelsohn stressed that "we continue to support the safety and efficacy profile of vernakalant [and] we look forward to working with Cardiome to conduct a transition that has the best interests of patients and their physicians in mind". William Hunter, interim CEO of Cardiome, added that the firm looks forward to continued advancement of the launch of Brinavess IV worldwide "and welcomes the opportunity to continue development of vernakalant oral worldwide and vernakalant IV in North America".