In a recent phase II study (REVIVE; NCT04057040), rusfertide (PTG-300) was deemed clinically effective and tolerable for the management of hematocrit (HCT) <45% in patients with polycythemia vera (PV) undergoing therapeutic phlebotomy (TP) with or without prior treatment with cytoreductive agents.
The researchers are now moving to phase III, in which they will first test rusfertide against a placebo. This will be a multi-center, global study. Recruiting began in January 2022.
Part 1a of the study will add rusfertide or placebo to ongoing TP treatment with or without concurrent cytoreductive treatment. This randomized, double-blind first phase will last 32 weeks.
Part 1b will add rusfertide to all patients in the placebo group who successfully completed part 1a. Patients already receiving rusfertide will continue treatment through week 52.
Part 2 will continue rusfertide treatment for all patients who successfully completed parts 1a and 1b. Part 2 will last an additional 104 weeks.
To participate in this study, patients must have a diagnosis of PV with either JAK2 V617F mutation or JAK2 exon 12 mutation. They must have had ≥3 incidences of TP within 6 months or ≥5 within 12 months prior to Week 0 for inadequate HCT control. Participants also must have a stable PV regimen if receiving cytoreductive therapy, and all must have <45% HCT white blood cells 4–20 x 109/L and platelets 100–1000 x 109/L at Week 0 prior to randomization. For the patients with TP alone, cytoreductive therapy must have been concluded 2-6 months prior to screening.
Any patient with clinically significant bleeding or thrombotic events within 2 months prior to randomization or invasive malignancy within the previous 5 years will be excluded.
During the study, patients receiving cytoreductive therapy may have their dose reduced for safety, but it cannot be increased for efficacy or control of HCT, thrombosis, or leukocytosis.
The primary end point will be absence of TP eligibility in all patients, whether receiving rusfertide or placebo, during Weeks 20-32 of part 1a.
The researchers will also look at the number of TPs from Week 0-32 and the proportion of patients with HCT <45% during the same period. They are interested in any change in fatigue score according to the Patient Reported Outcome Measurement Information System short form and the mean change in symptom score according to the Myelofibrosis Symptom Assessment Form through week 32.
This study is seeking to enroll 250 patients.
Verstovsek S, Kuykendall A, Hoffman R, et al. Verify: a phase 3 study of the hepcidin mimetic rusfertide (PTG-300) in patients with polycythemia vera. Abstract #1709. Presented at the 64th ASH Annual Meeting and Exposition; December 10-13, 2022; New Orleans, Louisiana.