Phase 1/2 study of high-dose palifermin for GVHD prophylaxis in patients undergoing HLA-matched unrelated donor HCT Available to Purchase

• Palifermin administered at single doses of 180 to 720 μg/kg before RIC was well tolerated.

• Patients who received RP2D (720 μg/kg) did not develop classic grade 2 to 4 AGVHD but incidence of moderate and severe CGVHD was unchanged.

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic cell transplantation (HCT). Palifermin, a recombinant N-truncated keratinocyte growth factor (KGF), protects epithelial tissues, including the thymus and gut. Although high-dose KGF prevents GVHD in preclinical models, lower doses of palifermin were ineffective in humans. We conducted a phase 1/2 trial evaluating high-dose palifermin for preventing severe chronic GVHD (CGVHD) in matched unrelated donor T-cell replete peripheral blood HCT after reduced-intensity conditioning (RIC). Using a 3+3 design, we determined the recommended phase 2 dose (RP2D), followed by an expansion phase. Palifermin (180-720 μg/kg) was given on day −7 before HCT. All 31 patients received fludarabine/cyclophosphamide RIC with tacrolimus, methotrexate, and sirolimus for GVHD prophylaxis. Palifermin was well tolerated, with self-limiting rash and pancreatic enzyme elevations as notable grade 3/4 adverse events. The RP2D was 720 μg/kg. Remarkably, no patients at this dose developed grade 2 to 4 acute GVHD (AGVHD [0/19]), although severe CGVHD rates (primary end point) remained unchanged compared to historical controls. Posttransplant lymphocyte phenotyping suggests palifermin modulates regulatory and naïve CD4⁺ T-cell numbers. These findings indicate that high-dose palifermin with RIC is safe and may prevent AGVHD, although it did not affect CGVHD rates in this study. This trial was registered at www.ClinicalTrials.gov as #NCT02356159.