Ropeginterferon Alfa-2b (P1101) vs. Anagrelide in Essential Thrombocythemia Patients With Hydroxyurea Resistance or Intolerance

This is a Phase 3 open-label, multicenter, randomized, active-controlled study designed to compare the efficacy and safety and tolerability of P1101 compared with ANA after 12 months of treatment as second-line therapy for subjects with ET who have had a suboptimal or failed response to HU.

PharmaEssentia Corporation is developing a pegylated (PEG) IFN-α product, P1101, for the treatment of ET. Available clinical data and experience with P1101 in PV shows that the compound, with proper dose modifications, is effective in controlling disease in a significant proportion of subjects with ET. Further, its increased serum half-life presents distinct advantages for ET treatment over that of standard IFN-α and other available PEG IFN-α therapy. This pivotal Phase 3 study will establish the efficacy and safety of P1101 in ET subjects. In core study phase, the enrolled subjects will be randomized into two arms, the test arm is P1101, the control arm is ANA. The overall duration for each eligible patient is 14 months, including screening (1 month), treatment (12 months) and follow-up (1 month) period. Efficacy evaluations, safety assessments, and PK and immunogenicity evaluations of P1101 will be performed. Evaluation of efficacy will include clinical laboratory assessments, allelic burden measurements of CALR, JAK-2, and MPL, spleen size measurements, bone marrow sampling, EQ-5D-3L, and MPN-SAF TSS completion. Evaluation of safety will include assessing vital signs, clinical safety laboratory tests, physical examinations, ECG evaluation, heart ECHO, lung X-ray, ECOG performance status, ocular examination, and AEs. Subjects who completed the end of treatment (EoT) and safety follow-up (EoS) visits of the SURPASS ET study and may benefit from P1101 therapy have the opportunity to receive P1101 treatment.