Calithera Biosciences has treated the first patient with advanced or metastatic solid tumours in a Phase I/II open-label clinical trial of the glutaminase inhibitor telaglenastat (CB-839).
The NCT03875313 trial involved the combination of Calithera’s CB-839 and Pfizer’s poly adenosine diphosphate ribose polymerase (PARP) inhibitor talazoparib, which is also known as Talzenna.
The Phase I/II trial will evaluate the safety and efficacy of the combination in patients with locally advanced / metastatic renal cell carcinoma (RCC), triple negative breast cancer (TNBC) and colorectal cancer (CRC) that are refractory or intolerant to standard therapies.
It will evaluate the potential of telaglenastat to sensitise tumours to talazoparib in patients regardless of mutations in the BRCA gene.
Calithera Biosciences president and CEO Susan Molineaux said: “The initiation of this clinical trial of telaglenastat in combination with talazoparib marks the first of two clinical trials that will evaluate telaglenastat with approved Pfizer therapeutics as part of this collaboration.
“We believe these new combination trials have the potential to broaden the opportunities for telaglenastat to improve patient outcomes.”
The combination of telaglenastat with PARP inhibitors has demonstrated synergistic activity in various preclinical cancer models.
Calithera signed a clinical trial collaboration agreement with Pfizer in October last year to evaluate telaglenastat in two clinical trials.
The first trial will involve the combination of telaglenastat and talazoparib and the second is a combination of telaglenastat with palbociclib, also known as Ibrance.
The investigational, novel glutaminase inhibitor telaglenastat has been designed to block glutamine consumption in tumour cells.
Last month, Calithera initiated a Phase I clinical trial with CB-280, an orally dosed arginase inhibitor being developed for the treatment of cystic fibrosis (CF).