Komet-008: A Phase 1 Study to Determine the Safety and Tolerability of Ziftomenib Combinations for the Treatment of KMT2A-Rearranged or NPM1-Mutant Relapsed/Refractory Acute Myeloid Leukemia

Background and Significance:

Relapsed or refractory (R/R) acute myeloid leukemia (AML) with nucleophosmin 1-mutations (NPM1-m) or KMT2A-rearrangment (KMT2A-r) remain a high unmet need. Ziftomenib is a potent and selective inhibitor of the interaction between menin and mixed-lineage leukemia (MLL) lysine[K]-specific methyltransferase 2A (KMT2A), which drives leukemogenesis in these subtypes. Preclinical data have demonstrated ziftomenib’s ability to target multiple types of menin-dependent AML clones, and that the antitumor activity of ziftomenib and other menin inhibitors in cell-derived xenograft (CDX) and patient-derived xenograft (PDX) models of KMT2A-r and NPM1-m AML is enhanced by the addition of FLT3 inhibitors such as gilteritinib and quizartinib. An ongoing Phase 1/2 study (KOMET-001) in R/R AML has demonstrated that ziftomenib monotherapy is safe and well tolerated and that the clinical activity at the recommended phase 2 dose (RP2D) is robust, as the rates of response were not affected by the presence of downstream co-mutations, such as FLT3 and IDH1 or IDH2. Given the monotherapy activity seen to date, the development of ziftomenib in combination with standard-of-care (SOC) chemotherapies or FLT3 inhibitors may provide increased clinical benefit for R/R AML patients with KMT2A-r or with NPM1-m with or without concurrent FLT3-mutations (FLT3-m) and warrants further investigation.

Study Design and Methods:

KOMET-008 (NCT# 05735184) is an open-label, dose escalation and expansion study to determine the safety, tolerability, and preliminary efficacy of ziftomenib when combined with SOC regimens for the treatment of either NPM1-m (Arm A) or KMT2A-r (Arm B) R/R AML. Each genetically defined arm will evaluate ziftomenib in combination with various SOC treatments in separate and independent cohorts, as outlined below:

• Arm A: NPM1-m R/R AML
  • Cohort A-1: Ziftomenib plus FLAG-IDA
  • Cohort A-2: Ziftomenib plus LDAC
  • Cohort A-3: Ziftomenib plus gilteritinib (for NPM1-m + FLT3-m R/R AML)
• Arm B: KMT2A-r R/R AML
  • Cohort B-1: Ziftomenib plus FLAG-IDA
  • Cohort B-2: Ziftomenib plus LDAC

The Part 1a dose escalation uses a i3+3 design, followed by dose expansion/validation in Part 1b. Key eligibility criteria include adults (≥18 years) with documented NPM1-m (±co-occurring FLT3-m) or KMT2A-r R/R AML, ECOG ≤2, prior hematopoietic stem cell transplant (HSCT) allowed, if recovered and prior gilteritinib allowed. Patients who receive an HSCT during study participation will be allowed to receive ziftomenib maintenance therapy upon recovery.

The primary objectives are to establish the safety and tolerability of ziftomenib when combined with SOC therapies (ie, dose limiting toxicities, AEs per CTCAE v5.0) and to identify the RP2D of ziftomenib for each SOC combination in each genetically defined cohort. Secondary endpoints include preliminary efficacy (including MRD-negative responses and number of patients able to receive stem cell transplant) and pharmacokinetics. Exploratory end points include biomarkers for efficacy and resistance and pharmacodynamic biomarkers potentially related to the activity of ziftomenib when combined with SOC treatments in adults with R/R AML with NPM1-m or KMT2A-r.