Cell Therapeutics has reported preliminary results of a Phase I/II clinical trial of pixantrone in 64 patients with relapsed aggressive non-Hodgkin's lymphoma who had previously failed one or two prior chemotherapy regimens, including the CHOP regimen. The two-part study was designed to determine the maximum tolerated dose and evaluate the drug's effectiveness in a combination known as CPOP, in which pixantrone replaces doxorubicin in the standard CHOP regimen. All patients on the study had received prior doxorubicin therapy and as such were at risk for developing severe cardiac toxicity with additional anthracycline therapy.
The CPOP regimen was highly effective, with complete response/unconfirmed complete response rates of 41 percent and 43 percent and overall response rates of 71 percent and 77 percent in the Phase I and II component of the study, respectively. Predominant side effects were blood-related and included 60 to 75 percent Grade 4 neutropenia and 23 percent febrile neutropenia. Grade 3 infections were observed at the 150 mg/m2 dose level (10 percent), but no Grade 3 infections have been reported to date at the 180 mg/m2 dose level. There was one case of congestive heart failure reported, which was felt by the investigator to be related to the patient's underlying cardiac disease.