Japanese pharmaceutical major Astellas has halted development of an immunosuppressant drug licensed from Sanofi-Aventis after disappointing results in Phase III trials.

The experimental drug, FK778, was being tested alongside Astellas’ already-marketed Prograf (tacrolimus) in patients undergoing organ transplants, but the results showed no clear benefit for the new agent over other Prograf-based combination therapies.

FK778 was the first of a new class of low molecular weight immunosuppressants, the malononitrilamides, that block both cellular and antibody immune responses. Astellas said it had not yet decided whether it would continue to develop the compound for other indications.