SAN ANTONIO — A clinical trial undertaken to evaluate etanercept tolerance by rheumatoid arthritis patients with comorbid conditions was stopped early because there were too few adverse events and infections to analyze, Scott W. Baumgartner, M.D., said at the annual meeting of the American College of Rheumatology.
The purpose of the study was to determine whether etanercept (Enbrel) use in patients with conditions such as diabetes might make them more prone to infections than has been suggested with initial trials of anti-tumor necrosis factor therapy, said Dr. Baumgartner, a private-practice researcher in Spokane, Wash.
The double-blind, placebo-controlled trial was to enroll 1,000 individuals, including 200 with diabetes, who would be treated and followed for 20 weeks each. After 535 patients were enrolled and treated, however, the data-monitoring safety board halted the trial, mainly because the infection rate was similar in both groups and the board believed that this result was unlikely to change.
At the same time, the trial researchers were having trouble recruiting subjects, since some people were reluctant to be assigned to placebo. Amgen Inc., the study sponsor, conferred with the Food and Drug Administration before canceling the study.
The majority of subjects in the study had either chronic obstructive pulmonary disease (42%) or diabetes (40%).
More subjects on placebo discontinued than did those on etanercept: 53 of 269 subjects compared with 29 of 266 subjects, respectively. The incidence of patients withdrawing specifically because of adverse events was 6% for placebo and 5% for etanercept.
The incidence of medically important infections in the study was 3.7% for placebo and 3.4% for etanercept. “And the types of infections seen were pretty similar, a few more [urinary tract infections] in the etanercept group and a few more [upper respiratory infections] in the placebo group,” Dr. Baumgartner said.
The deaths of four patients in the etanercept group and one patient in the placebo group appeared to be unrelated to the drug because the patients were very ill, Dr. Baumgartner said. Two patients died from coronary events, one from a subarachnoid hemorrhage, and one from respiratory failure.