LONDON – The scientist who discovered the immune system process on which TGN1412 is based spoke yesterday of his shock and sadness at the reactions suffered by those who volunteered to take part in the human trial.

Professor Thomas Hunig said that he, his co-workers, and his family were thinking of and praying for the recovery of the six young men, particularly those who were still in a critical condition.

Professor Hunig, the head of immunology at the University of Wurzburg, carried out early work on rodents using the equivalent antibody to manipulate the activity of T cells – white blood cells that play a crucial role in the immune system.

The biologist said that no toxic reactions had been seen in either the mice and rats in his research or the monkeys and rabbits on which other scientists later tested the humanized antibody drug TGN1412.

Professor Hunig, is a member of the board of the small German biotechnology company TeGenero behind the development of TGN1412, and was one of its founders when it was set up in 2000.

Speaking from Wurzburg last night he said: “I am completely shocked and surprised, and very sad. Although I am not a medic and I did not devise the [human] antibody or write the protocol I am extremely shocked at the harm that was done to these young people.

“All the pre-testing had shown no indications that any dangers would be expected.”

TeGenero has been working on using TGN1412 to overcome T cell-deficiency in patients with B-cell chronic lymphocytic leukemia, a rare blood cell cancer, and to switch off T cells involved in auto-immune disease such as rheumatoid arthritis.

This followed the discovery by Professor Hunig in 1997 that targeting the immune system receptor known as CD28 in mice and rats appeared to be an effective way of manipulating T cells and the functioning of the immune system.

Professor Hunig said: “The findings in the pre-clinical models had consistently been that one class of T-cells known as suppressor or regulatory T cells are much more reactive to this stimulation and therefore what one observed was immunosuppresion. What I can assure you is I know the responsible people at TeGenero made sure that everything was done in accordance with the laws and ethics of pre-clinical development.”

He added that despite his team giving doses of up to 250 times that given to the human volunteers this week to mice no harmful effects had been recorded, and said that had the tests on larger animals shown any toxic reaction the Medicines and Healthcare Products Regulatory Agency would not have given approval for the trial on humans.

Professor Hunig said reports of a dog having died after being given TGN1412 were untrue.

Meanwhile the MHRA said full details of the laboratory and animal tests for TGN1412 were submitted for its experts to assess before approval for the trial was granted on January 27.

It is usual for the first dose given to humans to be at least 100 times lower than that shown to be safe in animals. In the case of TGN1412 it was 500 times lower than that given to monkeys.

A spokesman for the MHRA said the agency gave permission for the human tests to go ahead without significant time lags between the first volunteer receiving his dose and the others because the pre-clinical trials had shown no sign of toxic reactions.

“The protocol indicated that the dosing of subjects was to be staggered over an overall two-hour period. The first dose administered in the trial was at least 500 times lower than the dose administered in animal trials that showed no adverse effect.