Core data set on safety, efficacy, and durability of hemophilia gene therapy for a global registry: Communication from the SSC of the ISTH.

BACKGROUND: Gene therapy for people with hemophilia (PWH) will soon become available outside current clinical trials. The World Federation of Hemophilia (WFH), in collaboration with International Society of Thrombosis and Hemostasis Scientific and Standardization Committee (ISTH SSC), the European Haemophilia Consortium (EHC), the US National Hemophilia Foundation (NHF), the American Thrombosis and Hemostasis Network (ATHN), industry gene therapy development partners and Regulatory liaisons have developed the Gene Therapy Registry (GTR), designed to collect long-term data on all PWH who receive hemophilia gene therapy. OBJECTIVE: The objectives of the GTR are to record the long-term safety and efficacy data post gene therapy infusion and to assess the changes in quality of life and burden of disease post-gene-therapy infusion. METHODS: The GTR is a prospective, observational, and longitudinal registry developed under the guidance of a multi-stakeholder GTR Steering Committee (GTR SC), composed of health care professionals, patient advocates, industry representatives, and regulatory agency liaisons. All PWH who receive gene therapy by clinical trial or commercial product will be invited to enrol in the registry through their hemophilia treatment centers (HTCs). The registry aims to recruit 100% of eligible post gene therapy PWH globally. Through an iterative process, and following the guidance of the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA), the GTR SC has developed a core set of data to be collected on all patients post gene therapy. RESULTS: The core data set includes demographic information, vector infusion details, safety, efficacy, quality of life and burden of disease. CONCLUSIONS: The GTR is a global effort to ensure that long term safety and efficacy outcomes are recorded and analysed and rare adverse events, in a small patient population, are identified. Many unknowns on the long-term safety and efficacy of gene therapy for hemophilia may also be addressed.

Functional validation of the genetic architecture of Salmonella Enteritidis persistence in 129S6 mice.

The Gram-negative bacteria, Salmonella, cause a broad spectrum of clinical diseases in humans, ranging from asymptomatic carriage to life-threatening sepsis. We have designed an experimental model to study the contribution of genetic factors to the persistence of Salmonella Enteritidis during the late phase of infection in 129S6/SvEvTac and C57BL/6J mice. C57BL/6J mice cleared the bacteria from their reticuloendothelial system within a period of 42 days, whereas the 129S6 mice still presented a high bacterial load. Using this model, we have identified ten Salmonella Enteritidis susceptibility loci (Ses1, Ses1.1, and Ses3-Ses10) associated with bacterial persistence in target organs of 129S6/SvEvTac mice using a two-locus epistasis QTL linkage mapping approach. Significant statistical interactions were detected between Ses1 on chromosome 1 and Ses5 on chromosome 7 and between Ses1 and Ses4 on chromosome X. In this study, we functionally validated the genetic architecture of Salmonella persistence in 129S6 mice using single- (129S6.B6-Ses1.2 that combines Ses1 and Ses1.1 loci, 129S6.B6-Ses4, and 129S6.B6-Ses5) and double-congenic mice (129S6.B6-Ses1.2/Ses4 and 129S6.B6-Ses1.2/Ses5). These experiments demonstrate functional interactions between Ses1.2 and Ses4 or Ses5 that improve Salmonella Enteritidis clearance, validating the critical role played by gene-gene interactions in the contribution to bacterial clearance heritability. Improved bacterial clearance in double-congenic mice could be explained by the impact of Ses4 and Ses5 in combination with Ses1.2 on TH polarization since a TH2 bias (decreased Ifng and increased Il4 mRNA levels and reduced IgG2a immunoglobulins in the serum) was observed in 129S6.B6-Ses1.2/Ses5 mice and a TH17 (high Il17 expression) bias in 129S6.B6-Ses1.2/Ses4.