Merck KGaA has resumed its clinical programme on the investigational cancer vaccine Stimuvax after a mid-stage trial was suspended in March after a brain inflammation case was reported.

Three months ago, the German company noted that one of 30 patients participating in a Phase II trial of the vaccine in patients with multiple myeloma developed encephalitis, or acute inflammation of the brain. The patient received the vaccine (licensed from the USA’s Oncothyreon) in combination with “an intensified schedule of low-dose cyclophosphamide, which is not used in the other Stimuvax studies”.

Merck stopped recruitment and treatment of patients in all studies of the BLP25 liposome vaccine, including the Phase III non-small-cell lung cancer trials called START and INSPIRE, as well as the late-stage STRIDE study in patients with breast cancer. Now the US Food and Drug Administration has partially lifted the clinical hold it had placed on Stimuvax trials, allowing the drugmakers to resume their START and INSPIRE, although STRIDE remains suspended.

Bernhard Kirschbaum, head of global R&D at the Darmstadt-headquartered firm’s Merck Serono division, said the company “worked constructively with the FDA and other health authorities to address the questions raised on the safety” of Stimuvax. He noted that “we have meanwhile received a number of regulatory approvals to restart in other countries and await approval in the remaining countries”.

Wolfgang Wein, head of oncology at Merck Serono, added that “we believe this therapeutic cancer vaccine has the potential to be a valuable addition to the future range of therapies for oncologists and their patients”. The company noted that “to ensure the safety of the study subjects, the protocols in the NSCLC trials are being amended to add specific safety measures”.