What a harmless antibiotic can teach us about GVL

In medicine, actions taken in good faith may lead to manifold unintended consequences, including off-target effects and unexpected toxicities of medications typically considered safe. In this issue of Blood, Vallet et al demonstrate that allogeneic hematopoietic stem cell transplant (HSCT) patients receiving azithromycin have alterations in T cell metabolism and increased T cell exhaustion (see figure), potentially underlying the loss of graft-versus-leukemia (GVL) activity and increased risk of disease relapse observed in the ALLOZITHRO trial.(1,2)

Automated summary

In medicine, well-intentioned actions can have unintended consequences, such as off-target effects and unexpected toxicities of supposedly safe medications. A recent study found that patients receiving azithromycin after allogeneic hematopoietic stem cell transplant had changes in T cell metabolism and increased T cell exhaustion, potentially contributing to the loss of graft-versus-leukemia activity and increased risk of disease relapse observed in the ALLOZITHRO trial.