Investigators at the University of Minnesota administered foscarnet to 25 umbilical cord transplant patients starting at day 7 post-transplant, in an attempt to prevent HHV-6 related graft failure. They then compared the results to 61 identically treated patients who were similar in age, disease risk and other factors. Although the incidence of HHV-6 reactivation was not significantly different between the two groups, the HHV-6 reactivation occurred later in the treated group (34 days vs 25.5 days). Neutrophil engraftment at day 42 was 96% compared to 75% for the control group (P<0.01). Multivariate analysis also identified the use of foscarnet as an independent predictor of improved platelet engraftment.
None of the foscarnet-treated patients died resulting in improved overall survival of 96% in the treated patients compared to 72% in the untreated patients (P<0.02).
Foscarnet is frequently used to treat HHV-6 encephalitis in transplant patients and is the only drug that has been approved by a regulatory board (Japan) for the treatment of HHV-6 disease. Unlike ganciclovir, it does not cause bone marrow suppression. However, foscarnet is known to have nephrotoxic effects.
Read the full paper: Jurdi 2020