The La Jolla, CA-based Ligand Pharmaceuticals said that Swiss Pharma giant Roche has terminated their collaboration and licensing agreement to develop a treatment for hepatitis C.

Ligand and Roche signed the drug development deal in 2008 to use Metabasis’ liver-targeting technology to find a new approach to treating the viral disease, and Roche made a $6.5 million milestone payment to Roche in April as a result of Roche progressing RG7348 into a Phase I study for the treatment of hepatitis C viral (HCV) infection.

Ligand filed regulatory paperwork indicating that Roche will be prohibited for ten years following the termination from developing or commercializing related compounds.

Recently Roche has started world-wide restructuring that spurred the company to write off $500 million in R&D work regarding RNAi programs.