Merck KGaA is making another bid to expand its multiple sclerosis franchise with the acquisition of a drug from troubled US firm Peptimmune.

The treatment in question is PI-2301, which is ready to go into Phase II trials for MS. It was developed by Cambridge, Massachusetts-based Peptimmune which filed for bankruptcy in March after a proposed $35 million financing failed to take off. Financial terms have not been disclosed.

PI-2301 is a second-generation peptide copolymer, ie a new form of Texa's blockbuster MS drug Copaxone (glatiramer acetate). Merck says it will investigate the application of the product in other autoimmune diseases.

Susan Herbert, head of global portfolio development at the German firm's Merck Serono unit, said that "over the years we have continuously worked on developing innovative treatment options that meet the individual needs of people living with MS". She added that "we are pleased to strengthen our development pipeline with the PI-2301 compound".

The German firm already markets its own MS blockbuster Rebif (interferon beta-1a) but has suffered a major blow this year when regulators on both sides of the Atlantic rejected its MS pill cladribine. Merck has since abandoned the project.