VEXAS syndrome (vacuoles in myeloid progenitors, E1 ubiquitin activating enzyme, X-linked, autoinflammatory manifestations and somatic) is an autoinflammatory condition caused by somatically acquired UBA1 mutations. Heiblig et al report on an international retrospective analysis of 30 patients with VEXAS syndrome treated with different Janus kinase (JAK) inhibitors, finding encouraging evidence supporting the use of the JAK1/2 inhibitor ruxolitinib with clinical remissions and reductions in steroid use seen in the majority of patients.

Although transcription factor CCAAT-enhancer binding protein α (C/EBPα) is critical for normal and leukemic differentiation, its role in cell and metabolic homeostasis is largely unknown in cancer. Here, multiomics analyses uncovered a coordinated activation of C/EBPα and Fms-like tyrosine kinase 3 (FLT3) that increased lipid anabolism in vivo and in patients with FLT3-mutant acute myeloid leukemia (AML). Mechanistically, C/EBPα regulated the fatty acid synthase (FASN)–stearoyl-CoA desaturase (SCD) axis to promote fatty acid (FA) biosynthesis and desaturation. We further demonstrated that FLT3 or C/EBPα inactivation decreased monounsaturated FA incorporation to membrane phospholipids through SCD downregulation. Consequently, SCD inhibition enhanced susceptibility to lipid redox stress that was exploited by combining FLT3 and glutathione peroxidase 4 inhibition to trigger lipid oxidative stress, enhancing ferroptotic death of FLT3-mutant AML cells. Altogether, our study reveals a C/EBPα function in lipid homeostasis and adaptation to redox stress, and a previously unreported vulnerability of FLT3-mutant AML to ferroptosis with promising therapeutic application. Significance: FLT3 mutations are found in 30% of AML cases and are actionable by tyrosine kinase inhibitors. Here, we discovered that C/EBPα regulates FA biosynthesis and protection from lipid redox stress downstream mutant-FLT3 signaling, which confers a vulnerability to ferroptosis upon FLT3 inhibition with therapeutic potential in AML. This article is highlighted in the In This Issue feature, p. 1501

The prognosis for relapsed or refractory (R/R) nucleophosmin 1–mutated (NPM1m) acute myeloid leukemia (AML) is poor and represents an urgent unmet medical need. Revumenib, a potent, selective menin inhibitor, was recently approved for the treatment of R/R acute leukemia with a KMT2A translocation in patients aged ≥1 year based on results from the phase 1/2 AUGMENT-101 study. Here, we present results from patients with R/R NPM1m AML enrolled in the phase 2 portion of AUGMENT-101. Enrolled patients received revumenib with or without a strong CYP3A4 inhibitor every 12 hours in 28-day cycles. Primary end points were rate of complete remission (CR) or CR with partial hematologic recovery (CRh; CR + CRh), safety, and tolerability. Secondary end points included overall response rate (ORR) and duration of response. As of 18 September 2024, 84 patients received ≥1 dose of revumenib. Median age was 63 years; 1 patient was aged <18 years. The protocol-defined, efficacy-evaluable population for the primary analysis included 64 adult patients (≥3 previous lines of therapy, 35.9%; previous venetoclax, 75.0%). The CR + CRh rate was 23.4% (1-sided P = .0014); the ORR was 46.9%. Median duration of CR + CRh was 4.7 months. Of 30 responders, 5 (16.7%) proceeded to hematopoietic stem cell transplant (HSCT) and 3 resumed revumenib after HSCT. Treatment-related adverse events led to treatment discontinuation in 4 patients (4.8%). Revumenib demonstrated clinically meaningful responses in this heavily pretreated, older population with NPM1m AML, including remissions that enabled HSCT. The safety profile of revumenib was consistent with previously reported results. This trial was registered at www.clinicaltrials.gov as #NCT04065399.