KRT-232 in Combination With TL-895 for the Treatment of R/R MF and KRT-232 for the Treatment of JAKi Intolerant MF

An Open-Label, Multicenter, Phase 1b/2 Study of the Safety and Efficacy of KRT-232 in Combination With TL-895 for the Treatment of Relapsed or Refractory Myelofibrosis and KRT-232 for the Treatment of JAK Inhibitor Intolerant Myelofibrosis.

This study evaluates KRT-232 in Combination With TL-895 for the Treatment of Relapsed or Refractory Myelofibrosis and KRT-232 for the Treatment of JAK Inhibitor Intolerant Myelofibrosis.

Cohorts 1 and 2 will undergo dose finding and dose expansion. Eligible patients will be randomly assigned to an open cohort, either Cohort 1 or Cohort 2. Cohort 3 will be conducted as a dose expansion, independent of Cohorts 1 and 2.

Cohort 1 will follow a 3+3 dose escalation design to determine the maximum tolerated dose (MTD)/maximum administered dose (MAD) and recommended Phase 2 dose (RP2D) of TL-895 administered QD in combination with KRT-232. A Safety Review Committee (SRC) will review the safety data during the dose escalation to decide on dose escalation and/or exploration of intermediate doses.

Cohort 2 will follow a 3+3 dose escalation design to determine the MTD/MAD and recommended RP2D of TL-895 administered BID in combination with KRT-232. An SRC will review the safety data during the dose escalation to decide on dose escalation and/or exploration of intermediate doses.

Cohort 3 will be conducted a 2-stage design. In stage 1, enrollment will continue until 15 evaluable patients have been enrolled. An SRC will review the data during the study and if there are ≥4 responders based on the futility criteria and safety data from Stage 1, Cohort 3 expansion will commence. If there are ≤3 patients responding to therapy, Cohort 3 will be terminated. Once expansion criteria have been met, Cohort 3 will be expanded to a total of 46 evaluable patients for Stage 2 analyses.

Inclusion Criteria:

• Confirmed diagnosis of primary MF, post-PV MF, or post-ET MF, (WHO 2016)
• ECOG ≤ 2
• Cohort 1 and Cohort 2: R/R following JAK inhibitor treatment
• Cohort 3: patients who are intolerant to JAK inhibitor treatment

Exclusion Criteria:

• Prior treatment with MDM2 inhibitors or p53-directed therapies
• Prior treatment with a BCR-ABL, phosphoinositide 3-kinase (PI3k), mammalian target of rapamycin (mTOR), bromodomain and extraterminal domain (BET), histone deacetylase (HDAC), or spleen tyrosine kinase (Syk) inhibitor
• Prior splenectomy
• Splenic irradiation within 3 months prior to the first dose of study treatment
• Clinically significant thrombosis within 3 months of screening
• Grade 2 or higher QTc prolongation