Webinar recap
This Becker’s Hospital Review webinar, presented by the chief of a transplantation and cellular therapy service at a major cancer center, examined how population PK/PD modeling can make outcomes after hematopoietic cell transplantation more predictable. The starting premise: the same conditioning regimen doesn’t produce the same exposure in every patient, because clearance of conditioning agents varies widely.
The central marker was early CD4+ immune reconstitution, defined as more than 50 CD4+ cells/µL on two consecutive measurements within 100 days of transplant. Across large cohorts, patients who reached it had markedly lower non-relapse mortality and better overall survival, and drug exposure during conditioning emerged as one of the strongest predictors of whether they did.
For busulfan, a harmonized population PK analysis of 674 children and young adults identified an optimal exposure range, and showed that AUC estimation methods differed so much between centers that outcomes couldn’t be compared without a common model. For anti-thymocyte globulin, higher exposure after transplant was associated with stunted CD4+ recovery, especially after cord blood transplant, an effect worsened by concurrent filgrastim. Interim results from an ongoing trial targeting lower post-transplant ATG exposure showed 80% of patients reaching CD4+ reconstitution, up from under half.
Fludarabine exposure also predicted outcomes, both in transplant conditioning and in lymphodepletion before CD19 CAR T-cell therapy, where lower exposure was associated with higher relapse. The presentation closed on what comes next: multi-agent models, and randomized trials comparing model-based dosing with standard body-surface-area dosing.
