CAR-T cell therapy and HHV-6B reactivation or disease
Kampouri E, Krantz EM, Xie H, et al. Human Herpesvirus-6 Reactivation and Disease Are Infrequent in Chimeric Antigen Receptor T-Cell Therapy Recipients. Blood. 2024; (doi: 10.1182/blood.2024024145).
Clinical evidence does not support routine monitoring of chimeric antigen receptor T-cell (CAR-T) therapy recipients for human herpesvirus-6B (HHV-6B) reactivation or disease, which occur at low rates in this patient population. The finding is based on results from two studies — one prospective and one retrospective. In the former, 89 participants were screened for HHV-6B for up to 12 weeks after CAR-T infusion, with reactivation documented in eight. After excluding three patients with chromosomally integrated HHV-6B, the cumulative incidence rate was 6% [95% confidence interval (CI), 2.2-12.5%], with low-level detection and no treatment needed. The retrospective analysis revealed HHV-6B encephalitis to develop even less frequently in this setting. Investigators examined HHV-6B detection in blood and/or cerebrospinal fluid (CSF) in 626 patients within 12 weeks of CAR-T infusion. Among 24 participants who had symptom-driven plasma testing, detection was confirmed in one. A single patient out of 34 who underwent CSF HHV-6B screening presented with possible encephalitis, for a cumulative incidence of 0.17% (95% CI, 0.02-0.94%). As with reactivation, no treatment was necessary for the affected individuals.