Merck halts Stimuvax trials after encephalitis case
Darmstadt – German Merck KGaA has suspended its clinical programme for the cancer vaccine Stimuvax, after a patient developed encephalitis in a Phase II trail in multiple myeloma. The company, which is developing the liposome encapsulated synthetic MUC1 peptide in programmes against solid cancers of epithelial origin (such as the lung cancer NSCLC or breast cancer), said it will now investigate the causes of the unintended adverse effect. The patient was randomized to an experimental arm of Stimuvax (BP1-7-KLH), in combination with an intensified schedule of low-dose cyclophosphamide, which is not used in the the other Stimuvax studies. Stimuvax, which mimicks the MUCIN 1 transmembrane protein overexpressed in many cancers, induces a strong CTL response upon vaccination. In Phase III studies, the vaccine which had been in-licenced from the Canadian company Biomira in 2006 (now Oncothyreon), prolonged overall survival of NSCLC patients from 13.3 to 30.6 months. Thus the drug, to be marketed by Merck in Europe and EMD Serono Inc in the US, was expected to become the next cancer blockbuster. Oncothyreon’s share were down by over 25% yesterday and analysts speculated that a coorelation between the drug and the adverse affect would affect Merck’s growth expectations. Merck said the action was a precautionary measure while investigating the cause of the adverse event. The suspension affects Merck’s Phase III clinical program, consisting of the non-small cell lung cancer (NSCLC) studies START with 1,300 patients and INSPIRE with additional 420 patients and the breast cancer study STRIDE with 900 volunteers, as well as the other recruiting studies.