Pharmacokinetics (PK) of bendamustine when administered in combination with rituximab in patients with non-Hodgkin lymphoma (NHL) and mantle cell lymphoma (MCL).

e18522 Background: The PK profile of bendamustine as a monotherapy in adult patients is well described. Because pathways of small molecules and monoclonal antibodies are distinct, a direct drug interaction between bendamustine and rituximab was not expected. Methods: In order to confirm the lack of a PK interaction, the population PK model that was developed based on the bendamustine monotherapy (120 mg/m2) was evaluated to determine its applicability to combination therapy (rituximab 375 mg/m2 on day 1, bendamustine 90 mg/m2 on days 1 and 2) in patients with NHL and MCL. Once the applicability was confirmed, model-predicted Bayesian bendamustine clearance (CL) values for monotherapy and combination therapy were generated and compared using the Wilcoxon signed rank test on the log-transformed CL values (alpha=0.05). Results: The previously developed population PK model in patients receiving bendamustine monotherapy was used to generate 500 sets of single-agent bendamustine concentrations at the same sampl...