Virus-specific T cells successfully target severe viral infections post HSCT

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Researchers from the Baylor College of Medicine have trialed a new, off-the-shelf method for treatment-related severe viral infections in patients who have received a hematopoietic stem cell transplant(HSCT). Adoptively transferred virus-specific T cells (VSTs) that recognized five common viral pathogens were generated and administered to a cohort of 38 patients with 45 infections in a phase 2 clinical trial.

Post HSCT viral infections can be fatal. Robust methods for dealing with particularly severe and drug-refractory infections are therefore essential for the effects of the original HSCT treatment to be realized. The team at Baylor created VSTs which recognized the following viral pathogens: Epstein-Barr virus (EBV), adenovirus (AdV), cytomegalovirus (CMV), BK virus (BKV), and human herpesvirus 6 (HHV-6). The team used a technique to produce the VSTs that they had pioneered in previous years; the method includes stimulating donor T cells with a peptide mixture spanning the target antigens.

The results showed that in the two viruses (BKV and HHV-6) that had never been targeted previously with an off-the-shelf product, the partial or complete response rates were 100 and 67% respectively. Overall, the single infusion administered garnered a response rate of 92%. The full results have been published in the Journal of clinical oncology; the team are confident that these support their conclusion that the ‘use of banked VSTs is a feasible, safe, and effective approach to treat severe and drug-refractory infections after HSCT. Furthermore, the multispecificity of the VSTs ensures extensive antiviral coverage, which facilitates the treatment of patients with multiple infections.’

Source: Off-the-Shelf Virus-Specific T Cells to Treat BK Virus, Human Herpesvirus 6, Cytomegalovirus, Epstein-Barr Virus, and Adenovirus Infections After Allogeneic Hematopoietic Stem-Cell Transplantation. Tzannou I et al.,Journal of clinical oncology, August 2017. DOI