The genomic landscape of juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a myeloproliferative neoplasm (MPN) of childhood with a poor prognosis. Mutations in NF1, NRAS, KRAS, PTPN11 and CBL occur in 85% of patients, yet there are currently no risk stratification algorithms capable of predicting which patients will be refractory to conventional treatment and therefore be candidates for experimental therapies. In addition, there have been few other molecular pathways identified aside from the Ras/MAPK pathway to serve as the basis for such novel therapeutic strategies. We therefore sought to genomically characterize serial samples from patients at diagnosis through relapse and transformation to acute myeloid leukemia in order to expand our knowledge of the mutational spectrum in JMML. We identified recurrent mutations in genes involved in signal transduction, gene splicing, the polycomb repressive complex 2 (PRC2) and transcription. Importantly, the number of somatic alterations present at diagnosis appears to be the major determinant of outcome

Giroctocogene fitelparvovec gene therapy for severe hemophilia A: 104-week analysis of the Phase 1/2 Alta study

•Giroctocogene fitelparvovec is the first gene therapy for hemophilia A that uses a recombinant AAV serotype 6-based vector.•Giroctocogene fitelparvovec was generally well tolerated with appropriate clinical management and showed efficacy at the highest dose. Patients with hemophilia A require exogenous factor VIII (FVIII) or non-factor hemostatic agents to prevent spontaneous bleeding events. Adeno-associated virus (AAV) vector–based gene therapy is under clinical investigation to enable endogenous FVIII production. Giroctocogene fitelparvovec is a recombinant AAV serotype 6 vector containing the coding sequence for the B-domain–deleted human F8 gene. In the ongoing phase 1/2, dose-ranging Alta study, 4 sequential cohorts of male participants with severe hemophilia A received a single intravenous dose of giroctocogene fitelparvovec. The primary end points are safety and changes in circulating FVIII activity. Interim results up to 214 weeks after treatment for all participants are presented. Eleven participants were dosed. Increases in alanine and aspartate aminotransferases were the most common treatment-related adverse events (AEs), which resolved with corticosteroid administration. Two treatment-related serious AEs (hypotension and pyrexia) were reported in one participant within 6 hours of infusion and resolved within 24 hours post-infusion. At the highest dose level (3 × 1013 vg/kg; n = 5), the mean circulating FVIII activity level at week 52 was 42.6% (range, 7.8%-122.3%) and at week 104 was 25.4% (range, 0.9%–71.6%) based on a chromogenic assay. No liver masses, thrombotic events, or inhibitors were detected in any participant. These interim 104-week data suggest that giroctocogene fitelparvovec is generally well tolerated with appropriate clinical management and has the potential to provide clinically meaningful FVIII activity levels, as indicated by the low rate of bleeding events in the highest-dose cohort. (ClinicalTrials.gov Identifier: NCT03061201