A Phase I Study Of Tp-3654, An Oral Pim Kinase Inhibitor, In Patients With Intermediate-2 Or High-Risk Primary Or Secondary Myelofibrosis (Mf)

Context: MF is characterized by bone marrow fibrosis (BMF), ineffective hematopoiesis, splenomegaly, and debilitating symptoms. Expression of PIM-1 is significantly upregulated in MF hematopoietic cells, indicating that PIM-1 is a potential therapeutic target in MF. TP-3654, an oral small-molecule investigational PIM-1 kinase inhibitor with favorable selectivity against other kinases, has been shown to inhibit proliferation and increase apoptosis in murine and human hematopoietic cells expressing the JAK2V617F mutation. TP-3654 alone and in combination with ruxolitinib normalizes leukocyte counts and reduces spleen size and BMF in JAK2V617F and MPLW515L murine MF models. Objective: To evaluate TP-3654 monotherapy in patients with MF. Design: Phase I, open-label, dose-escalation study (NCT04176198). Setting: Multicenter, US only. Patients or Other Participants: Key eligibility criteria include primary or secondary MF (post-polycythemia vera-MF/post-essential thrombocythemia-MF); intermediate-2/high-risk MF per Dynamic International Prognostic Scoring System (DIPSS); previously failed or are ineligible to receive Janus kinase inhibitors (e.g., ruxolitinib, fedratinib); grade ≥2 BMF; platelet count ≥50x109/L; absolute neutrophil count ≥1x109/L; peripheral blood blast counts Interventions: Patients receive oral TP-3654. Dose escalation, performed using a Bayesian Logistic Regression Model with Escalation with Overdose Control, will continue until identification of the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) is achieved. Dose expansion will follow. Main Outcomes Measures: Primary objectives: to determine MTD and/or identify the RP2D of TP-3654 monotherapy. Secondary objectives: to assess preliminary activity (spleen volume reduction, symptom improvement, and BMF reduction), determine QT interval changes, and establish the pharmacokinetic profile. Exploratory objectives: to study pharmacodynamic markers in peripheral blood and BM biopsies. This study is currently recruiting.