No chimeric antigen receptor therapy (CAR-T) is currently approved for WM. This study assessed safety and efficacy of CD20-targeted CAR-T in BTKi-refractory, heavily pre-treated WM patients. With a CR/VGPR rate of 80%, this treatment should be evaluated in larger trials. ClinicalTrials.gov number NCT03277729
Inherited bone marrow failure syndromes (IBMFS) are monogenic disorders characterized by single or multilineage cytopenias from hypoproliferative dyshematopoiesis. Diagnosis is challenging because of substantial clinical and pathological overlap between individual IBMFS entities and acquired diseases such as immune aplastic anemia. Conventional genetic testing using targeted panels or whole exome sequencing incompletely captures the spectrum of pathogenic variation, leaving a substantial proportion of cases undiagnosed. We evaluated the utility of upfront whole genome and transcriptome sequencing (WGTS) in 237 patients with suspected IBMFS using non-hematopoietic DNA. Median age was 29 years (range 3 months-76 years) and 34.6% were under 18 years. Clinically-accredited sequencing was performed with real-time return of results to guide patient management and familial testing. A molecular diagnosis was established in 87/237 patients (36.7%), spanning hereditary thrombocytopenia, telomere biology disorders, Diamond-Blackfan anemia, severe congenital neutropenia, Shwachman-Diamond syndrome, Fanconi anemia and other IBMFS. A further four patients were diagnosed with non-hematological genetic conditions and seven patients with secondary actionable findings. Novel pathogenic mechanisms including retrotransposon-mediated gene disruption were identified. Further, novel associations with primary IBMFS-like presentations (THRA) as well as definitive evidence of gene-disease associations (MEIS1, TUBB) were established. Acceptability of WGTS based on the established Theoretical Framework of Acceptability was high among patients and carers. Upfront WGTS in suspected IBMFS provides a high diagnostic yield when compared with other genomic approaches, identifies actionable genomic abnormalities, and expands the spectrum of disease mechanisms and gene associations in IBMFS.
The first-in-class allosteric BCR::ABL1 inhibitor asciminib has expanded the therapeutic landscape of chronic myeloid leukemia (CML). However, the molecular mechanisms underlying secondary resistance remain incompletely understood. We investigated clinically observed asciminib resistance mutations by integrating structural modeling, hydrogen-deuterium exchange mass spectrometry (HDX-MS), quantitative biochemical assays and molecular dynamics simulations. Resistance mutations were grouped into two mechanistically distinct classes: Mutations within the BCR::ABL1 myristate pocket (class I) and mutations located up to 40 Å from the asciminib binding site in the kinase N-lobe, SH2-kinase domain (KD) linker and SH3 domain (class II). HDX-MS demonstrated that asciminib induces conformational stabilization across the KD extending beyond the myristate pocket, establishing a long-range allosteric network. We show that class I mutations reduced asciminib affinity up to 90-fold, consistent with steric interference at the binding site. In contrast, class II mutations retained wildtype binding affinity despite conferring clinical resistance. Instead, the class II mutations F359I and M244V increased intrinsic kinase activity and enhanced BCR::ABL1 autophosphorylation, indicating overactivation. Molecular dynamics simulations revealed allosteric communication linking the myristate and ATP-binding pockets, which is disrupted by class II mutations. Together, these findings establish that asciminib resistance arises through two distinct mechanisms: direct impairment of drug binding or disruption of the asciminib binding-induced autoinhibited conformation. Our study provides a mechanistic framework for understanding resistance to allosteric BCR::ABL1 inhibitors and has important implications for resistance monitoring, combination therapies and therapeutic sequencing.
In an international registry analysis of 201 patients with SM-AHN, KIT D816V-selective TKI exposure was associated with longer overall survival (37.9 vs 17.8 months; P <.001) and lower 36-month incidence of acute myeloid leukemia transformation (5.9% vs 27.1%; P <.001).
