February 14, 2006

Allos Therapeutics has announced the publication of results from a preclinical study designed to compare the activity of a pralatrexate (PDX)/gemcitabine combination relative to a commonly used combination of methotrexate/cytarabine (ara-C) in treating lymphoma. Results of the study, which were reported in Clinical Cancer Research, indicate that the combination of pralatrexate followed by gemcitabine was superior to the combination of methotrexate/ara-C in vitro and in vivo models of lymphoma, and was more potent in inducing apoptosis in certain lymphoma cell lines.

The study assessed the effects of single agent treatments and the pralatrexate and methotrexate combinations in parallel in a large B-cell lymphoma cell line. Results of the analysis indicated that in vitro, the scheduled combination of pralatrexate/gemcitabine possessed greater cytotoxicity compared to the methotrexate/ara-C combination, as well as significantly increased apoptosis in a cell line specifically selected for its resistance to pralatrexate. In vivo studies demonstrated a significant reduction of tumor burden in mice treated with pralatrexate/gemcitabine compared to those treated with methotrexate/ara-C.