Jung, Chul Won

PURPOSE Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with AML harboring an internal tandem duplication mutation of FLT3 ( FLT3-ITD) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202 ) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit. METHODS Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS. RESULTS Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575). CONCLUSION Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

AbstractCWP232291 (CWP291) is a small-molecule inhibitor of Wnt signaling that causes degradation of β-catenin via apoptosis induction through endoplasmic reticulum stress activation. This first-in-human, open-label, dose-escalation study to evaluate the safety, maximum tolerated dose (MTD), and preliminary efficacy of CWP291 enrolled 69 patients with hematologic malignancies (acute myeloid leukemia [AML], n = 64; myelodysplastic syndrome, n = 5) in 15 dose-escalation cohorts of 4 to 334 mg/m2 using a modified 3+3 design and 1 dose-expansion cohort. CWP291 was administered IV daily for 7 days every 21 days. The most common treatment-emergent adverse events (TEAEs) were nausea (n = 44, 64%), vomiting (n = 32, 46%), diarrhea (n = 25, 36%), and infusion-related reactions (n = 20, 29%). Grade ≥3 TEAEs in >3 patients (5%) were pneumonia (n = 8, 12%); hypophosphatemia (n = 6, 8%); leukocytosis, nausea, cellulitis, sepsis, and hypokalemia (n = 5 each, 7% each); and hypertension (n = 4, 6%). Dose-limiting toxicities included nausea (n = 3) and abdominal pain, anaphylactic reaction, myalgia, and rash (n = 1, each); the MTD was defined at 257 mg/m2. CWP232204, the active metabolite of CWP291, showed pharmacokinetic linearity on both days 1 and 7, and a terminal half-life of ∼12 hours. Among 54 response-evaluable AML patients, there was one complete response at a dose of 153 mg/m2 and one partial response at 198 mg/m2; bone marrow blast percentage reduced from a median of 58.3% to 3.5% and 15.0% to 4.2%, respectively. Future studies will explore CWP291, with a mechanism of action aimed at eradication of earlier progenitors via Wnt pathway blockade, as combination therapy. This trial was registered at www.clinicaltrials.gov as #NCT01398462.