Approximately 63 participants will be randomized to one of three doses to receive Recifercept either
Low Dose
Medium Dose
High Dose
Participants will will attend the clinic at baseline and at Day 1, 4, 8, 15, 29 & then Month 2, 3 6, 9 & 12. Assessments include safety, blood sampling, physical examination, vital signs, anthropometric body measurements & patient/caregiver quality of life questionnaires
Participants will received treatment with Recifercept for 12 months. All participants who complete the study and in the opinion of the investigator, continue to have a positive risk:benefit profile, will be offered to enroll into an open-label extension (OLE) study.
A PK cohort will include 12 participants who will randomly receive a single dose of 3 mg/kg of Phase 2 study (process 1c) formulation and a single dose of 3 mg/kg of the proposed Phase 3 (process 2) study formulation in a cross over study. Dose of the cohort could be changed due to emerging safety and efficacy data in the study.