Calithera Biosciences, Inc. announced the decision to terminate its phase 2 KEAPSAKE clinical trial based on a lack of clinical benefit observed in patients treated with telaglenastat in an interim analysis. The phase 2 randomized, placebo-controlled, double-blind KEAPSAKE study was designed to evaluate the safety and anti-tumor activity of telaglenastat plus standard-of-care chemoimmunotherapy as front-line therapy among patients with stage IV non-squamous non-small cell lung cancer (NSCLC) whose tumors have a KEAP1 or NRF2 mutation. At the time of unblinding on October 27, 2021, there were 40 patients randomized. The available efficacy data at unblinding, including investigator-assessed progression-free survival (PFS), did not demonstrate clinical benefit, and analysis of the data led to the conclusion that there was a very low probability for the study to achieve a positive result. No difference in safety profile was seen between the two arms. The company has communicated these findings to the U.S. Food & Drug Administration (FDA) and has voluntarily discontinued the phase 2 study with agreement from members of the KEAPSAKE Steering Committee. Calithera has no plans to continue the development of telaglenastat at this time. Calithera estimates the cost savings resulting from the discontinuation of this trial will be $10-15 million.