Factors Affecting Post-transplant Cyclophosphamide (PTCy) Efficacy

The primary objective of this single-arm, pilot study is to determine whether pharmacogenetics (PG) of Cy-related candidate genes from the recipients and/or donors (haploidentical and matched related donor HCTs only) germ-line DNA is associated with incidence and severity of acute and chronic GVHD. Secondary objectives include determining whether pharmacogenetics (PG) of Cy-related candidate genes from the recipients and/or donors (haploidentical and matched related donor HCTs only) germ-line DNA is associated with Cy (and metabolites) exposure and toxicities; quantifying Cy (and related metabolites) exposure measured as the area under the concentration time curve (AUC) from zero to 24 hours both before (day -6) and after transplant (day +3), and correlate exposure with incidence of acute and chronic GVHD, and Adverse Events of Special Interest (AESIs); and determining whether immune activation or polarization prior to or following Cy GVHD prophylaxis is associated with grade of acute or chronic GVHD grade and AESIs. Safety objects include evaluating Cy administered, adverse events of special interest (including deaths while on study therapy), selected laboratory parameters (including time to neutrophil recovery), and immunosuppressant concomitant medications administration. Initially, 20 participants (HCT recipients and their respective haploidentical or matched related donors) will be enrolled with a subsequent 100 additional subjects enrolled.