An FDA panel voted unanimously that clinical trial data was not adequate to support approval of Cell Therapeutics' pixantrone for patients with relapsed or refractory aggressive non-Hodgkin lymphoma (NHL). Cell Therapeutics’ shares dropped from $0.91 to $0.40 with the news.
The firm reported in December 2009 that the FDA asked the Oncologic Drugs Advisory Committee to convene to discuss and vote on whether pixantrone was approvable. They voted 9–0 against its sanction. FDA’s final decision on whether or not to approve the drug is expected to be made on April 23, 2010.
Pixantrone is a topoisomerase II inhibitor with an aza-anthracenedione molecular structure that differentiates it from anthracyclines and other related chemotherapy agents. Cell Therapeutics NDA was based on the PIX 301 Extend (expanding the reach of anthracyclines with pixantrone in relapsed or refractory aggressive NHL disease) trial, a single-agent trial of pixantrone for patients who received two or more prior therapies and who were sensitive to treatment with anthracyclines. The trial enrolled 140 patients who were randomized to receive either pixantrone or another currently marketed single-agent drug.
The study achieved its primary endpoint of a higher rate of confirmed and unconfirmed complete remissions compared to patients treated with standard chemotherapy. Additionally, patients treated with pixantrone experienced a statistically significant improvement in median progression-free survival compared with other single-agent chemotherapeutic agents.
Yet concerns remain about the side-effect profile of pixantrone. Those receiving the drug had a low incidence of severe neutropenia complicated by either fever, infections, severe vomiting, or diarrhea. Pixantrone patients also had a higher incidence of leucopenia and numerically more severe cardiac events, with only one considered related to the study drug by the investigator.