VST therapy as a hospital-exemption ATMP was applied to six pediatric transplant recipients with refractory viral infections (adenovirus in three; EBV-driven disease in three, including one with concurrent CMV/EBV/ADV) after allogeneic HSCT. Patients had failed conventional antivirals or immunochemotherapy.
VST products were generated from donor material via automated CliniMACS Prodigy Cytokine Capture System with IFN-γ CCS, stimulated by viral peptide pools, and released per the ALLOVISTA protocol. A single intravenous infusion ranging from 1.01×10^5 to 1.85×10^6 cells (median 2.5×10^5) was administered.
Virological response was assessed by quantitative PCR up to 4 weeks post-infusion; clinical outcomes included acute GVHD surveillance and survival. Virological outcomes were evaluable in five patients, with four achieving at least a 1-log reduction in viral load; two achieved complete clearance by week 4 (one EBV, one ADV).
Two additional patients had marked but incomplete or transient reductions; one patient showed minimal change. Despite antiviral activity, four children died from progressive EBV disease, ADV infection, HL relapse, and multi-organ/fungal complications; two patients with complete responses remained alive with sustained viral suppression at last follow-up.
Two patients with complete viral clearance remained alive with sustained remission of viremia at last follow-up.