Cubist Pharmaceutical, Inc. data from a recently concluded phase 2 study of HepeX-B as maintenance therapy to prevent re-infection with hepatitis B in patients with liver transplants showed that patients with either dose of HepeX-B experienced no evidence of viral re-infection. The data also showed fewer and less serious adverse experiences reported in both HepeX-B groups as compared to the HBIg group, although the differences were not statistically significant given the number of patients in the trial.

According to a company release, patients who were treated with HepeX-B as well as HBIg also received concurrent HBV polymerase inhibitor. The company will be reviewing phase 2 results with the US Food and Drug Administration early in 2006.

The data is derived from patients who have completed at least 6 months of therapy, which was the treatment duration at which the primary endpoint was measured. Eleven patients received monthly 20 mg infusions of HepeX-B; ten received monthly infusions of 40 mg HepeX-B; and nine received monthly infusions of 5000 IU HBIg.

The company recently met with the FDA to discuss proposed changes to the method of manufacture and formulation of HepeX-B. Specifically, Cubist plans to shift from the use of hybridoma cells to Chinese Hamster Ovary (CHO) cells and to switch to subcutaneous delivery prior to phase 3. The objective of the manufacturing change is to provide a stable platform for commercialisation. The switch to subcutaneous administration is meant to increase patient convenience and compliance with chronic therapy. The company will meet again with the FDA in early 2006 to discuss the implications of these changes on the next stage of the clinical programme.

HepeX-B is a combination of two fully human monoclonal antibodies that target HBV surface antigens. It is currently in evaluation for the prevention of infection by HBV in liver transplant patients who have been maintained on HBIg. HepeX-B already has been granted orphan drug status in both the US and the European Union.

Cubist Pharmaceuticals Inc. is a biopharmaceutical company focused on the research, development and commercialisation of anti-infective products that address unmet medical needs in the acute care environment.