Merck Serono has rolled out a new version of the multiple sclerosis drug Rebif in the UK, which, it claims, offers a much better tolerability profile compared to its predecessor.

The new formulation of Rebif (interferon beta-1a), approved in Europe in August last year and destined to replace the original version of the drug from March, is the first and only MS therapy that is serum-free both from animal and human derived components, and thereby poses a much less risk of reaction at the site of injection.

Approval was based on the results of a two-year Phase IIIb study that clearly demonstrated its favourable benefit-to-risk profile, with MS patients given the new version experiencing a near three-fold reduction in injection-site reactions, the group said.

Positive implications
“Injection site reactions can lead to discontinuation of therapy in some patients,” explained Professor Gavin Giovannoni from The Royal London Hospital. “The notable reduction in these reactions with Rebif New Formulation has positive implications for treatment tolerability and adherence,” he added.

The new version of Rebif has been developed in the same strengths and pharmaceutical forms as the original 8.8, 22 and 44 mcg forms, which together pulled in sales of 317 million euros in the fourth quarter of 2007.