Extension Study of P1101 in Japanese Patients Who Have Completed Phase 2 Single Arm Study in Polycythemia Vera (PV) or Phase 3 Study in Essential Thrombocythemia (ET)

What this Trial Is About

Researchers are evaluating the long-term safety, efficacy, and tolerability of P1101 (Ropeginterferon alfa-2b) in patients with Polycythemia Vera (PV) or Essential Thrombocythemia (ET) who have previously participated in specific earlier studies. This Phase 3 open-label, multicenter, single-arm study focuses on patients who completed 52 weeks of treatment with P1101 or anagrelide in prior trials. The study aims to monitor continued outcomes and effects over an extended period. Participants will receive P1101 treatment, starting at the dose used at Week 50 in their prior study or at 250 mcg if previously treated with anagrelide. The dose of P1101 can be adjusted up to 500 mcg depending on individual condition. This study continues as a post-marketing clinical trial after P1101's marketing approval. Treatment includes conventional care such as phlebotomies and low-dose aspirin alongside P1101 given subcutaneously every two weeks. During the study, participants will undergo safety evaluations including vital signs, lab tests, physical exams, ECG, heart echo, lung X-ray, eye exams, and performance status assessments. Efficacy will be assessed through lab tests, genetic mutation measurements, spleen size, and bone marrow sampling. Researchers will monitor blood counts, spleen size changes, and thrombotic or hemorrhagic events over approximately two years, with the primary focus on maintaining phlebotomy-free complete hematologic response.

Extension Study of P1101 After Completion of Phase 2 Study in PV Patients or Phase 3 Study in ET Patients