Study of the Safety and Efficacy of RPH-104 in Preventing Recurrences in Patients With Idiopathic Recurrent Pericarditis

The goal of this clinical trial is to evaluate the safety and efficacy of RPH-104 for long-term use in a population of patients with idiopathic recurrent pericarditis who completed the main study CL04018068.The primary objective of the study is to evaluate the safety of RPH-104 80 mg once every 2 weeks in patients with idiopathic recurrent pericarditis who completed the main study.

Inclusion Criteria:Patient who fully completed per protocol a 24-week randomized withdrawal period (for the first 20 randomized patients), or the preparation therapy after the end of enrolment into the randomized withdrawal period in the main study CL04018068.Voluntarily signed and dated Patient Informed Consent Form for participation in this study.The patient's ability and willingness, according to the investigator, to follow the schedule of visits, the study procedures and follow the protocol requirements, including the following:Come to the study site every 2 weeks for the study drug administration by qualified site staff; orLearn how to perform subcutaneous injections and do it on their own at home as per protocol of this study.Exclusion Criteria:Unwillingness or inability of the patient to perform the study procedures in accordance with the Protocol.Any medically important event that was reported in a patient during his/her participation in the main study CL04018068, and, in the opinion of the Investigator, is a reason for not including this patient in this open-label study.Pregnant and lactating women or women planning pregnancy during the study or within 2 months after the last dose of the study drug.Women of childbearing potential who do NOT agree to use highly effective contraception methods throughout the study, starting from the moment of signing the informed consent form and for at least 8 weeks after the last dose of the study drug.OR Men who are sexually active and do NOT agree to use highly effective contraception methods throughout the study, starting from the moment of signing the informed consent form and for at least 8 weeks after the last dose of the study drug.Highly effective contraception methods include:sterilization in women: surgical bilateral removal of the ovaries (with or without removal of the uterus) or ligation of the fallopian tubes at least 6 weeks before the start of the study therapy. In the case of removal of only the ovaries, the reproductive status of a woman should be confirmed by a subsequent assessment of hormone level;sterilization in men, at least 6 months before the start of the study therapy with proper documentation of the absence of sperm in the ejaculate after vasectomy. For women participating in the study, a sexual partner after a vasectomy should be the only partner;using a combination of any two of the following methods (a+b or a+c or b+c):oral, injectable or implanted hormonal contraceptives; in the case of the use of oral contraceptives, women should continuously use the same drug for at least 3 months before the start of the study therapy;an intrauterine device or contraceptive system;barrier methods of contraception: condom or occlusive cap (diaphragm or cervical cap/contraceptive vaginal ring) with spermicidal foam/gel/film/cream/vaginal suppository.The need to use a live (attenuated) vaccine during the study or within 3 months after the last dose of the study drug. Live attenuated vaccines include vaccines against the following viruses: measles, rubella, mumps, chickenpox, rotavirus, flu (as a nasal spray), yellow fever, polio (oral polio vaccine); vaccines against tuberculosis (BCG), typhoid fever (oral typhoid vaccine) and typhus (typhus vaccine). Immunocompetent family members of the patient should not be vaccinated with the oral polio vaccine during the patient's participation in the study.Other medical conditions or laboratory abnormalities, which may increase the potential risk associated with participation in the study and treatment with the study drug, or may affect the interpretation of the results of the study, and which, in the opinion of the Investigator lead to patient ineligibility for this study.Parallel participation in other clinical trials (except for the main study CL04018068) at the time of screening or the use of any unapproved (investigational) drugs less than 4 weeks or 5 half-lives (whichever is greater) before screening.