Study of SX-682 Alone and in Combination With Oral or Intravenous Decitabine in Subjects With Myelodysplastic Syndrome

This study will determine the safety profile, maximum tolerated dose (MTD), dose-limiting toxicities (DLT), and recommended Phase 2 dose (RP2D) of SX-682 in the treatment of patients with Myelodysplastic Syndromes (MDS).

Participants will receive twice daily oral SX-682 for six 28 day cycles. If patients are responding well to the treatment they can continue SX-682 treatment. The first participants will be administered 25 mg orally twice daily. Unless dose limiting toxicities occur, participants will enroll and receive the following increasing twice daily doses of SX-682: 50 mg, 100 mg, 200 mg, and 400 mg. After establishing the maximum tolerated dose 140 additional participants will be enrolled at the recommended phase 2 dose. Participants will receive continuous SX-682 twice daily oral therapy in 28-day cycles for a total of 6 cycles. The expansion dose cohort will be stratified into IPSS (a) low and intermediate-1 (N=20 SX-682 alone in HMA naive, N=20 SX-682 alone in HMA failure, N=20 SX-682 + DEC-C in HMA-naïve, N=20 SX-682 + DEC-C in HMA-failure) and (b) intermediate-2 and high risk (N=20 SX-682 alone in HMA failure, N=20 SX-682 + DEC-C in HMA-naive, N=20 SX-682 + DEC-C in HMA-failure) MDS. For patients responding well at the end of 6 cycles treatment may continue until disease progression or an adverse event leads to SX-682 discontinuation. Except for blood product transfusions, concurrent therapy for Myelodysplastic Syndromes is not permitted.