Dr. Ganesh Suntharalingam and colleagues at Northwick Park Hospital in northwest London said the immune system overreaction, known as a cytokine storm, was an unforeseeable consequence of taking the drug.
In the New England Journal of Medicine, the doctors have noted that their case will help understand what happens when immune system overreacts, which might well again happen in future clinical trails.
Six of the eight men involved in the trail became ill shortly after they were given infusions of TGN1412, a drug engineered to affect immune system cells known as CD28 cells.
The drug made by made by German biotechnology firm TeGenero AG were given to six men who were paid volunteers in a study being run by U.S. drug research company Parexel International Corp on behalf of TeGenero.
While two of the men involved in the trial got a dummy infusion, six others who got the drug reported headaches, shivers, nausea, diarrhea and lower back pain within 90 minutes of taking the drug.
One of the patients involved in the trail became so ill that he had to be put on the ventilator following which the doctors decided to put the others also into intensive care. This was followed by a dramatic two weeks during which the previously healthy men developed difficulty in breathing and had symptoms that looked like a serious sepsis infection.
Initially, the doctors struggled to keep the men going as they tried to figure out what had gone wrong until the blood test showed that they had a cytokine storm. Such over-response of the immune system has been described in patients with avian influenza. It took two weeks for the patients to stabilize and recover.
"Regulatory authorities, who tested TGN1412 from the same batch as the infused drug, found no errors in its manufacture, formulation, or administration and found no contamination," the researchers added.