Assay data support glutaminase as cancer target
SOUTH SAN FRANCISCO, Calif.—Calithera Biosciences Inc. has released results from studies of primary human breast tumors that support glutaminase as a possible target in triple-negative breast cancer. Through the use of a novel pharmacodynamic assay that measures glutaminase inhibition in a single post-dose tumor biopsy sample, significant glutaminase inhibition was seen following oral administration of CB-839, a potent, selective and orally bioavailable glutaminase inhibitor in Phase 1 clinical trials as a treatment for solid and hematological malignancies. CB-839 demonstrated potent glutaminase inhibition in both primary triple-negative breast cancer tumor lysates and in tumors from a triple-negative breast cancer model. Glutaminase inhibition of 75 percent to 84 percent was seen in tumor biopsy samples from three solid tumors patients enrolled in early dose cohorts of the ongoing trial.