NEW YORK – Calithera Biosciences on Monday said that although a trial exploring the activity of telaglenastat and cabozantinib (Exelixis' Cabometyx) in renal cell carcinoma patients failed to meet its primary endpoint, the San Francisco-based firm will continue to explore telaglenastat in a molecularly defined non-small cell lung cancer subpopulation.
In the CANTATA trial, involving 444 advanced or metastatic renal cell cancer patients, the median progression-free survival was 9.2 months for patients on telaglenastat-cabozantinib versus 9.3 months for those on cabozantinib and placebo. Due to the study's failure, Calithera will reduce its workforce, currently at around 90 employees, by 35 percent and focus its resources on ongoing studies that show promise.
According to Calithera President and CEO Susan Molineaux, among the company's various pipeline opportunities, there is a strong biological rationale to continue to study telaglenastat, a glutaminase inhibitor, in KEAP1/NRF2-mutated NSCLC patients in the KEAPSAKE trial. The 120-patient Phase II study is randomizing non-squamous, stage IV NSCLC patients to either telaglenastat combined with chemotherapy and the immune checkpoint inhibitor pembrolizumab (Merck's Keytruda), or just the chemo-immunotherapy combo.
Approximately 20 percent of NSCLC patients harbor KEAP1 or NRF2 mutations in their tumors. In order to determine eligibility for KEAPSAKE, patients are tested for these mutations on Guardant Health's Guardant360 liquid biopsy next-generation sequencing test. The first patient was dosed within KEAPSAKE in September.
Calithera estimated that it has approximately $115 million in cash, cash equivalents, and investments as of Dec. 31, 2020, which can fund operations through 2022, including the release of interim data from KEAPSAKE. The company anticipates between $1.3 million and $1.5 million in one-time severance-related charges related to the workforce reduction, which is slated for completion in the first quarter.
In Monday morning trading on the Nasdaq, Calithera's stock price was down around 42 percent at $2.84.