It was aimed to examine the efficacy and safety of once daily dosage schema of colchicine in pediatric patients with FMF compared to twice daily dosage schema.

In this 24-week, multicentric, randomized, controlled, noninferiority trial, pediatric patients newly diagnosed with FMF, carrying homozygote or compound heterozygote mutation and did not receive any treatment, were included. Patients were randomly assigned using block randomization method to receive treatment with once or twice daily doses. Clinical and laboratory characteristics and medication side effects were recorded and compared between groups. The study complied with Good Clinical Practice and the Consolidated Standards for Reporting of Trials (CONSORT) statement.

Study design This study was conducted by members of the FMF Arthritis Vasculitis and Orphan disease Research in Pediatric Rheumatology (FAVOR, www.favor.org.tr) at 10 centers in Turkey. This is a multicentric randomized controlled, noninferiority trial of two parallel groups being followed up in pediatric rheumatology outpatient clinics. The randomization was done at baseline visit and patients were assessed in two more visits, three months apart. The study complied with Good Clinical Practice (GCP) and the Consolidated Standards for Reporting of Trials (CONSORT) statement.

Participants Inclusion criteria Pediatric patients who were newly diagnosed with Familial Mediterranean Fever according to Yalcinkaya or Tel-Hashomer criteria and who were confirmed with the genetic analysis as having compound heterozygote or homozygote mutation were enrolled. Eligible patients between ages of 5-16 and weighted 15-30 kg who and had not received any treatment were included. All patients included were asked the physicians to be proved and recorded as having at least one FMF attack before enrollment for the study.

Exclusion criteria Patients with a major congenital malformation, with a risk of pregnancy, and with other chronic diseases such as organ transplantation, hepatic disorder chronic kidney disease and AA amyloidosis, thyroid disease or rheumatologic disorders other than FMF, were excluded.

Baseline assessment and Outcome Measures At the baseline visit, medical history and complaints about the disease were questioned and physical examination and laboratory tests were performed. In following visits, any attack or findings due to colchicine since the last visit were investigated in addition to baseline visit.

Interventions The once daily dosage group was prescribed as once daily at 08:00 a.m. and the twice daily dosage group received the treatment twice daily at 08:00 a.m. and 08:00 p.m. Disease severity was assessed via Mor scoring system, modified for pediatric patients in all visits. A physician from each center was chosen to be responsible for data collection. After each visit the data was registered to a web-based registry system in "www.favor.org.tr" web site. To ensure accurate, complete, and reliable data, the following procedures were followed: data collection, encoding, and storage had been provided for the centers; a training session had been held to provide instruction on the protocol; periodic meetings had been held with study coordinators the principal investigator stayed in contact with the study coordinators by mail, telephone, and/or fax; and finally a data manager reviewed and evaluated the data.

Colchicine dosage The required colchicine dosage was calculated as total 1 mg daily according to internationally accepted advisory. All patients were prescribed 0.5 mg Colchicine tablets. Patients in once daily dosage group were given 2 tablets of Colchicine at 08.00 a.m. Twice daily dosage group received 1 tablet of 0,5 mg Colchicine at 08:00 a.m. and 1 tablet of 0,5 mg Colchicine at 08:00 p.m.

Inclusion Criteria:

• Diagnosed with Familial Mediterranean Fever according to Yalcinkaya or
• Tel-Hashomer criteria
• Diagnosis confirmed with the genetic analysis as compound heterozygote or
• homozygote mutation
• Patients between ages of 5-16 and weighted 15-30 kg
• Not received any treatment for FMF

Exclusion criteria:

• Major congenital malformation
• Organ transplantation
• Hepatic disorder
• Chronic kidney disease
• AA amyloidosis
• Thyroid disease
• Rheumatologic disorders other than FMF