Calithera begins Phase II trial of CB-839 to treat renal cell carcinoma


Pharmaceutical firm Calithera Biosciences has begun a Phase II clinical trial of CB-839 in combination with Afinitor (everolimus)‎ for the treatment of patients with renal cell carcinoma (RCC).

CB-839 is being developed based on the findings that cancer cells require a nutrient called glutamine for their growth and survival. The investigational candidate is designed to inhibit the glutaminase enzyme, in turn leading to tumour growth inhibition.

The randomised, double-blind, placebo controlled, multi-centre, international Phase II trial will assess the safety and efficacy of the combination therapy in 250 metastatic clear cell RCC patients.

Subjects who received a minimum of two previous lines of systemic therapy, comprising a VEGFR-targeting tyrosine kinase inhibitor and one of either Cabometyx (cabozantinib) or an active PD-1/PD-L1 inhibitor will be enrolled into the trial.

"The initiation of this study marks an important milestone for our company, as it is the first randomised trial of CB-839 that we believe has the potential for the US Food and Drug Administration (FDA) registration and approval."

The trial will compare CB-839 and everolimus combination with the combination of placebo and everolimus.

Calithera Biosciences president and CEO Susan Molineaux said: “Despite the advances in the treatment of renal cell carcinoma, there remains a significant unmet need for patients who have progressed following treatment with an anti-PD1 and/or tyrosine kinase inhibitors.

“The initiation of this study marks an important milestone for our company, as it is the first randomised trial of CB-839 that we believe has the potential for the US Food and Drug Administration (FDA) registration and approval.”

The trial is to be performed at various centres in the US, Canada and Europe and will evaluate progression-free survival as its primary endpoint.

CB-839 secured fast-track designation from the FDA for the treatment of RCC.