Efficacy and Safety of RPH-104 for Resolution and Prevention of Recurring Attacks in Adult Subjects With Familial Mediterranean Fever With Resistance to or Intolerance of Colchicine

The study is supposed to enroll (randomize) (n= not less than 28, not less than 14 per group), so that not less than 24 to complete study in full (including all the treatment period visits and follow-up period visits - Visit 11 for patients who agreed to participate in the Open-label extension (OLE) study; Visit 11 and Visit 12 for those who do not wish to participate in the OLE study; given potential withdrawal at screening the number of screened subjects (signed Informed Consent Form (ICF) is planned to be up to 84.

The study will consists of three following periods:

1. Screening period (up to 12 weeks); Throughout the screening the subjects will be monitored to identify "marker" attacks and verify the subject eligibility. The subjects having an attack during screening period and meeting inclusion/exclusion criteria will be enrolled into treatment period. 2. Double-blind randomized placebo-controlled treatment period (16 weeks);

The subjects enrolled will be randomized to one of the treatment groups in 1:1 ratio: * RPH-104 group to receive subcutaneous (SC) injections according to the following regimen: 160 mg on Day 0, 80 mg on Day 7, Day 14 and once every 2 weeks (q2w) thereafter; * placebo group to receive matching SC injections on Day 0, Day 7, Day 14 and q2w thereafter.

Efficacy assessment will be performed at Visit 2 and Visit 3, and subsequently every 2 weeks up to Visit 10 inclusive; safety assessment will be performed throughout the study (Visit 1 - Visit 12). In a case of adverse event (AE) development (or other safety reasons), additional unscheduled safety visits could be performed throughout the study. Starting from Visit 2, additional unscheduled visits due to suspected development of FMF attack could be performed. In a case of a recurrent attack, the patient should come to the study site within 2 days from the attack onset for the attack registration.

The treatment response (i.e. the resolution of FMF "marker" attack/absence of recurrent attacks) will be assessed throughout the treatment period with the investigational products administered both blind and open-label. Responders will continue the study treatment with the assigned investigational products (RPH-104 or placebo as a single SC 2 mL injection q2w, based on the randomization group) in a blinded manner. In non-responders, the following treatment modifications are possible: * In a case the "marker" attack has not resolved by Visit 2 - the treatment group will be unblinded:

* patients from placebo group will be switched to active treatment with RPH-104 in SC injections at a dose of 160 mg (single dose, first injection) followed by administration of 80 mg in 7 days at the Attack + 7 days Visit (with procedures corresponding to Visit 2), and 80 mg at the next scheduled Visit performed 1 week later than initially scheduled (with procedures corresponding to this Visit) after the Attack + 7 days Visit. * patients from RPH-104 group will receive planned RPH-104 80 mg administration. * In a case of recurrent FMF attack confirmation at a scheduled visit - the treatment group will be unblinded (if still blinded):