Intra-patient Dose Escalation Study to Investigate Safety and Feasibility of Vactosertib in Treating Anemic MPN Patients

This is a two-tiered multi arm Phase 2 trial of vactosertib (TEW-7197) for the treatment of anemia in Ph-neg MPNs. Both tiers use a rule-based, accelerated dose escalation scheme to efficiently assess the potential of vactosertib to safely and effectively treat anemic patients with Ph-neg MPNs. The first tier of this trial (Tier 1) is an intra-patient dose finding study in 12 patients that uses a low starting dose of vactosertib for all patients. Treatment dose is escalated according to prospectively-defined rules, and a toxicity and treatment effect algorithm during the period of 16 weeks (4 treatment cycles). If pre-established efficacy and safety endpoints are met, then Tier 1 of the study will be followed by a Tier 2 expansion study with an additional 25 patients for a period of 24 weeks (6 treatment cycles). Vactosertib will be administered concurrently with the patient's current treatment (if any). Prior to enrollment, patients must be on a stable dose of their current therapy for 3 months prior to entering the study. Supportive care measures including packed red blood cell (PRBC) transfusions for HGB \<7g/dL, or symptomatic anemia, will be permitted. Administration of erythropoiesis stimulating agents (ESAs), however, will not be permitted on the trial (patients recruited would have serum EPO \>125 U/L above which the benefit of ESAs is not supported).