Earlier trials indicated similar drug has serious side effects

The revelation brings into question how much regulatory authorities knew about the drug candidate's potency and its failure to consult with external specialists before they authorised the UK study.

Additonally, damaging accusations regarding regulatory authorities' associations with the pharmaceutical industry have led to calls for a public enquiry examining the regulation process.

The trials that have raised the alarm were presented at a meeting of the >American Society of Clinical Oncology​ (ASCO) last May.

The study, entitled: "Tumour regression in patients with metastatic renal cancer treated with a monoclonal antibody to CTLA4 (MDX-010)," aimed to unbalance the antagonistic network in which T-lymphocytes express both co-stimulatory (CD28) and inhibitory (CTLA4) receptors.

The team used a monoclonal antibody to block the CTLA4 engagement, activating the lymphocytes.

Toxicities, which included enteritis, hypophysitis and meningitis, were observed in 12 of the 20 subjects of whom one patient underwent a colectomy for perforation.

Angus Dalgleish, a professor of cancer at St George's hospital medical school, south London, told >The Sunday Times​: "The previous studies which caused similar severe side effects were in patients already suffering from cancer, but [the researchers] should have known they would get a meltdown because this drug was hitting exactly the same immune response pathways."​

The trial, which began last Monday, involved six volunteers, who were injected with the drug (TGN1412) and two with placebo. All six of the volunteers who had been given the drug developed serious symptoms.

TGN1412 binds to a molecule called CD28, a molecule that is present on the cell surface of T lymphocytes.

Previous laboratory tests demonstrated that TGN1412 is a CD28 agonist stimulating the physiological function of CD28 causing more T cells to be created.

The MHRA responded in the interview by saying: "The application in this particular clinical trial was reviewed by experienced MHRA staff including medical, toxicological and pharmaceutical experts."​

"From the data provided there was nothing to suggest that this product would be hazardous to man at the doses to be used in the clinical trial. In addition we know that the study was reviewed and approved by an independent ethics committee and by our German counterparts."​

Parexel, the American firm contracted to run the human trials for the drug firm TeGenero, said in a statement: "We believe that best practices were followed and the appropriate policies and procedures were adhered to."

Monoclonal antibodies have been hailed as the cutting edge of science. Instead of shutting down harmful processes in the body as a traditional drug might do, monoclonal antibodies are engineered to kick start beneficial systems into action.

However, trials of monoclonal antibodies has shown the drugs carry "considerable risks" of side effects including fever, severe pain, limb weakness, uncontrollable tremor, vomiting and diarrhoea.