Anakinra may not improve chronic fatigue syndrome severity in women
There were no clinically important or statistically significant differences between anakinra and placebo groups in Checklist Individual Strength subscale score at four weeks or the end of follow-up.
The anti-inflammatory biologic drug anakinra may not reduce fatigue severity in women with chronic fatigue syndrome (CFS), a study found.
Interleukin-1 (IL-1), a pro-inflammatory cytokine, has been associated with CFS in some studies, and there is extensive experience with blocking IL-1 in different diseases with the IL-1 receptor antagonist anakinra. In this study, researchers from the Netherlands randomized 50 women ages 18 to 59 with severe fatigue leading to functional impairment to receive either daily 100-mg anakinra injections or placebo for four weeks, followed by an additional 20 weeks of follow-up after treatment for all of the participants.
The primary outcome of fatigue severity was assessed via questionnaire at four weeks. The secondary outcomes of level of impairment, physical and social functioning, psychological distress, and pain severity were assessed at four and 24 weeks.
Study results were published online March 7 by Annals of Internal Medicine.
There was no clinically meaningful difference in fatigue severity with anakinra. At four weeks, 8% of anakinra recipients (2 of 25 women) and 20% of placebo recipients (5 of 25 women) reached a fatigue level within the range reported by healthy people. There were no clinically important or statistically significant differences between groups in Checklist Individual Strength (CIS) subscale score at four weeks (mean difference, 1.5 points [95% CI, −4.1 to 7.2 points]) or the end of follow-up. The CIS is a validated questionnaire with a subscale assessing fatigue severity that is often used in patients with CFS. Scores range from 8 to 56, with higher scores reflecting more severe fatigue.
No statistically significant between-group differences were seen for any secondary outcome at four weeks or at the end of follow-up. One patient in the anakinra group discontinued treatment because of an adverse event, and patients in the anakinra group had more injection-site reactions (68% [17 of 25 women] vs. 4% [1 of 25 women]).
The researchers concluded that if IL-1 plays a role in CFS, blocking it with anakinra has no effect. “It is possible that peripherally administered anakinra does not reach the brain in sufficient concentrations to have a biological effect, or that IL-1 has a limited role in CFS,” they wrote.