Novel Leukemia Therapy Also Slows Solid Tumor Growth in Mice

A new class of drugs (phosphoinositide-3-OH kinase δ [PI(3)Kδ] inhibitors) exhibits remarkable activity against chronic lymphoid leukemias in humans (NEJM JW Oncol Hematol Jan 29 2014). The PI(3)Kδ enzyme is active in both lymphocytes and polymorphonuclear leukocytes but not in solid tumor cells; nevertheless, a British team has found that PI(3)Kδ inhibitors also are effective against solid tumors in mice.

The team injected malignant melanoma, breast cancer, lung cancer, and thymoma cells into mice; dramatic improvement was noted in tumor progression and survival in PI(3)Kδ-inhibitor–treated mice compared with untreated mice. A line of mice that spontaneously develops pancreatic cancer also fared dramatically better with inhibitor treatment.…