MADRID – Abatacept doesn’t appear to increase the risk of opportunistic infections among patients with rheumatoid arthritis, Kevin Winthrop, MD, reported at the European Congress of Rheumatology.
After reviewing all of the extant safety data on the drug – all of its clinical trial and open-label study data, and case reports of abatacept-associated adverse events – Dr. Winthrop concluded that infections, including tuberculosis, fungal overgrowth, herpes simplex and herpes zoster, occur either with similar frequency or less often than among those taking placebo.
“In fact, there is a sense that abatacept is actually safer,” than some other disease-modifying antirheumatic drugs,” said Dr. Winthrop, an infectious disease specialist at Oregon Health and Science University, Portland. However, there are few data comparing safety among the agents – something he said should be examined in more detail.
His review encompassed 16 clinical trials comprising 7,044 patients who took the drug (21,330 patient/years of abatacept exposure) and 1,485 patients who took placebo. He conducted two analyses: one for opportunistic bacterial and fungal infections, and one for herpes simplex and herpes zoster.
The first analysis found 45 opportunistic bacterial or fungal infections among those taking abatacept – an incidence rate of 0.21/ 100 person-years. There were seven such infections in the placebo group – an incidence rate of 0.56/100 person-years. This difference was statistically significant.
In the abatacept cohort, there were two cases of bronchopulmonary aspergilliosis (IR 0.01) and three fungal eye infections (IR 0.01). There was also one case of gastrointestinal candidiasis; one fungal esophagitis; one cryptococcal meningitis; two pneumonias (one pseudomonal and one caused by Pneumocystis jirovecii); and two cases of respiratory monoliasis. All of these infections had an incidence rate of less than 0.01/100 person-years.
There were 17 tuberculosis cases (IR 0.08/100 person-years). Three cases were latent. Six of the cases were pulmonary and five were extrapulmonary. Two cases were unspecified. All occurred in regions with high or moderate endemic tuberculosis levels.
A meta-regression analysis examined the risk of opportunistic infections in the patients taken from the placebo-controlled clinical trials only (2,653 abatacept, 1,485 placebo). The estimated frequency of an opportunistic infection was 0.15% among those taking the drug and 0.48% among those taking placebo.
The herpes analysis examined the placebo-controlled clinical trial population as well. There were 57 cases of herpes simplex (IR 2.5/100 person-years) among those taking abatacept and 22 among those taking placebo (IR 1.8/100 person-years). The difference was not statistically significant.
There were 44 cases of herpes zoster among those taking abatacept (IR 1.9/100 person-years) and 21 among those taking placebo (IR 1.7/100 person-years).
“Basically, I think what we’re seeing here is a whole lot of nothing,” Dr. Winthrop said.
Dr. Winthrop has been a consultant for Pfizer, AbbVie, Bristol-Myers Squibb, UCB Pharma, Roche/Genentech, Amgen, Galapagos, and Eli Lilly.
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