TeGenero AG of Würzburg, Germany, announced that six subjects participating in a clinical trial to evaluate the safety of the company's study drug TGN1412 (CD28-SuperMAB®) experienced adverse events, leading British regulators from the Medicines and Healthcare Products regulatory agency to order an immediate suspension of the trial. All six study volunteers receiving TGN1412 were hospitalized in London following massive inflammatory responses; two are in critical condition and four are in serious condition. The cause of the inflammatory responses remains unknown.

The study, managed by the clinical research organization Parexel International of Waltham, Massachusetts, was the first human testing of TGN1412, a fully humanized immunomodulatory superagonistic anti-CD28 monoclonal antibody under development for the treatment of autoimmune and inflammatory diseases such as rheumatoid arthritis and multiple sclerosis, as well as certain cancers such as leukemia.

The clinical trial was approved by the Medicines and Healthcare Products regulatory agency, the UK regulatory authority responsible for clinical trial approval, and the local ethics committee. TeGenero and Parexel indicated that the drug was developed in accordance with all regulatory and clinical guidelines and standards, and that in pre-clinical studies, TGN1412 was shown to be safe.

—A. Techman