A first-in-human, phase 1, dose escalation study of SGR-2921 as monotherapy in patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome.

Abstract

TPS6590 Background: Cell division cycle 7-related protein kinase (CDC7) is a cell cycle kinase that maintains DNA replication by phosphorylation and activation of the minichromosome maintenance protein 2 and 4 (MCMs), components of the replicative DNA helicase. Due to the CDC7's central role in maintaining replication fork integrity, chemical inhibition of CDC7 can ultimately lead to cancer cell death. SGR-2921 is an oral, small molecule inhibitor of CDC7. Preclinical studies demonstrate that SGR-2921 has potent anti-proliferative activity in AML cell lines representative of difficult to treat patient populations, agnostic of serious mutations (including those with p53 mutations), BTK resistance, and multiple prior lines of treatment. This anti-tumor activity has also been demonstrated in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) AML models. Methods: This is a phase 1, FIH, open-label, single-agent, two-arm, dose escalation study (NCT#05961839) designed to evaluate safety and tolerability and identify the recommended phase 2 dose (RP2D) of SGR-2921 as monotherapy in subjects with relapsed or refractory (R/R) AML, high risk (HR) MDS, or very high risk (VHR) MDS. The study utilizes an accelerated titration design with single patient cohorts that transitions to a 3+3 design once a single Grade 2 event is observed. This is a multicenter global study (US, Spain and France). SGR-2921 will be administered orally, once daily, utilizing a 5-day on and 9-day off dosing schedule over a 28-day cycle. A maximum of 144 patients will be enrolled into dose escalation and exploratory cohorts. To evaluate the effect of CYP3A4 inhibition on SGR-2921 exposure, subjects will be enrolled into one of two staggered, parallel study treatment arms, according to concomitant administration with (Arm B) or without (Arm A) azole antifungals that are strong CYP3A4 inhibitors. A single dose PK run-in will be required for subjects enrolled into the first 3 cohorts of each treatment arm. Subjects will be treated at increasing doses of SGR-2921 until the maximum tolerated dose (MTD) is exceeded. A RP2D will be selected from one of the tolerable dose levels. Key study inclusion criteria include: Age ≥ 18 years of age; Life expectancy ≥ 8 weeks; Confirmed diagnosis of R/R AML or HR and VHR MDS; Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. Key study exclusion criteria include: Active malignancies not related to AML or MDS within two years prior to the first dose or requiring ongoing treatment; active CNS leukemia; QTcF ≥470 msec. The primary objectives are to evaluate the safety and tolerability of SGR-2921 as monotherapy and to identify the RP2D. Secondary objectives include evaluating SGR-2921 pharmacokinetics and investigating preliminary antitumor activity. Clinical trial information: NCT05961839 .