Pentamidine + Salvage Chemo for Relapsed/Refractory Classical Hodgkin Lymphoma

The primary objective of this Phase I study is to determine the maximum tolerated dose (MTD) of Pentamidine. A two-stage continual reassessment method (CRM) will be employed to determine dose escalation levels and the maximum tolerated dose (MTD) of Pentamidine. Specifically, a modified two-stage CRM will be employed with 2 patients per cohort at each dose level. The trial starts with an escalation design from the lowest dose (2 mg/kg) with a traditional 2+2 dose escalation method. After occurrence of the first DLT, dose assignment will be determined by the CRM (2 patients/per cohort) using empirical model with restrictions to avoid dose-skipping and escalation immediately after a toxicity outcome. A maximum of 12 patients will be enrolled into the trial during the escalation phase. Once the MTD is reached, an additional 4 patients will be treated at this dose. Thus, 6 or more patients will be treated at the MTD. The target DLT rate is 33% and the investigators choose to use 0.10, 0.20 and 0.33 as prior toxicity distribution. CRM simulations indicate optimal performance of this design with high dose recommendation probabilities (at least 48%) and more patients allocated to the correct dose