The NIH says six patients who received different doses made from the original batch in the spring show no signs of illness. Thursday's suspension leaves about 250 people in 46 NIH studies waiting to hear when they will receive other experimental treatments.
A facility at the NIH's research hospital makes modest quantities of experimental drugs for those studies. NIH workers discovered the two contaminated vials in April. Officials say there is no evidence of any other contamination. But last month, Food and Drug Administration inspectors found problems with manufacturing quality practices that NIH must correct.