Interventions for reducing inflammation in familial Mediterranean fever

Abstract

Background: Familial Mediterranean fever, a hereditary auto-inflammatory disease, mainly affects ethnic groups living in the Mediterranean region. Early studies reported colchicine as a potential drug for preventing attacks of familial Mediterranean fever. For those people who are colchicine-resistant or intolerant, drugs such as rilonacept, anakinra, canakinumab, etanercept, infliximab, thalidomide and interferon-alpha might be beneficial. This is an updated version of the review. Objectives: To evaluate the efficacy and safety of interventions for reducing inflammation in people with familial Mediterranean fever. Search methods: We used detailed search strategies to search the following databases: CENTRAL; MEDLINE; Embase; Chinese Biomedical Literature Database (CBM); China National Knowledge Infrastructure Database (CNKI); Wan Fang; and VIP. In addition, we also searched the clinical trials registries including ClinicalTrials.gov, the International Standard Randomized Controlled Trial Number Register, the WHO International Clinical Trials Registry Platform and the Chinese Clinical Trial Registry, as well as references listed in relevant reports. Date of last search: 21 August 2018. Selection criteria: Randomized controlled studies (RCTs) of people diagnosed with familial Mediterranean fever, comparing active interventions (including colchicine, anakinra, rilonacept, canakinumab, etanercept, infliximab, thalidomide, interferon-alpha, ImmunoGuard™ (a herbal dietary supplement) and non-steroidal anti-inflammatory drugs) with placebo or no treatment, or comparing active drugs to each other. Data collection and analysis: The authors independently selected studies, extracted data and assessed risk of bias. We pooled data to present the risk ratio or mean difference with their 95% confidence intervals. We assessed overall evidence quality according to the GRADE approach. Main results: We included nine RCTs with a total of 249 participants (aged three to 53 years); five were of cross-over and four of parallel design. Six studies used oral colchicine, one used oral ImmunoGuard™ and the remaining two used rilonacept or anakinra as a subcutaneous injection. The duration of each study arm ranged from one to eight months. The three studies of ImmunoGuard™, rilonacept and anakinra were generally well-designed, except for an unclear risk of detection bias in one of these. However, some inadequacy existed in the four older studies on colchicine, which had an unclear risk of selection bias, detection bias and reporting bias, and also a high risk of attrition bias and other potential bias. Neither of the two studies comparing a single to a divided dose of colchicine were adequately blinded, furthermore one study had an unclear risk of selection bias and reporting bias, a high risk of attrition bias and other potential bias. We aimed to report on the number of participants experiencing an attack, the timing of attacks, the prevention of amyloid A amyloidosis, any adverse drug reactions and the response of a number of biochemical markers from the acute phase of an attack, but data were not available for all outcomes across all comparisons. One study (15 participants) reported a significant reduction in the number of people experiencing attacks at three months with 0.6 mg colchicine three times daily (14% versus 100%), risk ratio 0.21 (95% confidence interval 0.05 to 0.95) (low-quality evidence). A further study (22 participants) of 0.5 mg colchicine twice daily showed no significant reduction in the number of participants experiencing attacks at two months (low-quality evidence). A study of rilonacept in individuals who were colchicine-resistant or intolerant (14 participants) also showed no reduction at three months (moderate-quality evidence). Likewise, a study of anakinra given to colchicine-resistant people (25 participants) showed no reduction in the number of participants experiencing an attack at four months (moderate-quality evidence). Three studies reported no significant differences in duration of attacks: one comparing colchicine to placebo (15 participants) (very low-quality evidence); one comparing single-dose colchicine to divided-dose colchicine (90 participants) (moderate-quality evidence); and one comparing rilonacept to placebo (14 participants) (low-quality evidence). Three studies reported no significant differences in the number of days between attacks: two comparing colchicine to placebo (24 participants in total) (very low-quality evidence); and one comparing rilonacept to placebo (14 participants) (low-quality evidence). No study reported on the prevention of amyloid A amyloidosis. One study of colchicine reported loose stools and frequent bowel movements (very low-quality evidence) and a second reported diarrhoea (very low-quality evidence). The rilonacept study reported no significant differences in gastrointestinal symptoms, hypertension, headache, respiratory tract infections, injection site reactions and herpes, compared to placebo (low-quality evidence). The ImmunoGuard study observed no side effects (moderate-quality evidence). The anakinra study reported no significant differences between intervention and placebo, including injection site reaction, headache, presyncope, dyspnea and itching (moderate-quality evidence). When comparing single and divided doses of colchicine, one study reported no difference in adverse events (including anorexia, nausea, diarrhoea, abdominal pain, vomiting and elevated liver enzymes) between groups (moderate-quality evidence) and the second study reported no adverse effects were detected. The rilonacept study reported no significant reduction in acute phase response indicators after three months (low-quality evidence). In the ImmunoGuard™ study, these indicators were not reduced after one month of treatment (moderate-quality evidence). The anakinra study, reported that C-reactive protein was significantly reduced after four months (moderate-quality evidence). One of the single dose versus divided dose colchicine studies reported no significant reduction in acute phase response indicators after eight months (low-quality evidence), while the second study reported no significant reduction in serum amyloid A concentration after six months (moderate-quality evidence). Authors' conclusions: There were limited RCTs assessing interventions for people with familial Mediterranean fever. Based on the evidence, three times daily colchicine appears to reduce the number of people experiencing attacks, colchicine single dose and divided dose might not be different for children with familial Mediterranean fever and anakinra might reduce C-reactive protein in colchicine-resistant participants; however, only a few RCTs contributed data for analysis. Further RCTs examining active interventions, not only colchicine, are necessary before a comprehensive conclusion regarding the efficacy and safety of interventions for reducing inflammation in familial Mediterranean fever can be drawn.