There are encouraging signs that the men who suffered major side effects after taking part in a Phase I trial of TeGenero’s antibody drug TG1412 might be staging a recovery.

Three of the men have been taken off organ support, and while two are still in a critical condition and sedated, they are showing some signs of improvement, according to doctors at Northwick Park Hospital where the trial took place.

In the aftermath of the trial, questions are being asked as to whether all procedures and guidelines were adhered to in conducting the study. An investigation into the trial by the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) is continuing, and while no timeline has been given for a verdict, it is expected to take weeks rather than days.

In a statement released yesterday, the clinical research organisation that carried out the study, Parexel, said an internal review “continues to support that the protocol approved by the MHRA and the Ethics Committee was adhered to properly, and that best practices and policies and procedures were correctly followed.”

Earlier, TeGenero confirmed that TGN1412 had been tested in both rabbits and monkeys which, in normal circumstances, would be expected to uncover any species-specific problems.

The company has also updated a Frequently-Asked Questions document on its website to answer – and refute - allegations in the press that side effects were seen in monkeys that could have served as a warning of the adverse reactions seen in the trial.

Lymph node swelling was seen in monkeys, but TeGenero stressed this was not a drug-related side effect and was simply evidence of the drug’s expected effect on the immune system.