A Population Pharmacokinetic and Pharmacodynamic Evaluation of Pralatrexate in Patients With Relapsed or Refractory Non-Hodgkin's or Hodgkin's Lymphoma

In a pralatrexate phase I study, patients displayed a high incidence of mucositis of grades 3 and 4. Preliminary evaluations of the pharmacokinetics of the drug and its association with mucositis suggested that pralatrexate exposure (area under the concentration–time curve (AUC)) could be controlled with body size (e.g., weight or body surface area)–based dosing and that pretreatment with folic acid and vitamin B12 might diminish the incidence and severity of mucositis. The study was amended, with revised dosing and vitamin B12 administration. Data from 47 patients were evaluated using NONMEM. Weight and methylmalonic acid (MMA) level were predictive of pharmacokinetic (PK) variability. AUC and MMA level were positively correlated with the risk of developing mucositis. A lower AUC schedule with vitamin B12 pretreatment may control mucositis without compromising efficacy. The covariates identified in this study are comparable with other antifolate analogs. The application of modeling was a critical step in the development of pralatrexate, yielding important suggestions for dose, scheduling, and pretreatment modifications. Clinical Pharmacology & Therapeutics (2009); 86, 2, 190–196 doi:10.1038/clpt.2009.80