6 November 2018 - - US-based biopharmaceutical company FLX Bio, Inc has established a clinical trial collaboration agreement with US-based Merck to conduct a Phase 1/2 study evaluating the safety and efficacy of the combination of Keytruda (pembrolizumab), Merck's anti-PD-1 therapy, and FLX Bio's investigational oral small molecule CCR4 inhibitor, FLX475, in patients with multiple types of cancer, the company said.

The open-label, dose-escalation and cohort expansion Phase 1/2 study is enrolling patients with multiple types of cancer at leading cancer centers across the United States, Australia and Asia.

In addition to evaluating the safety and tolerability of FLX475 as a monotherapy and in combination with pembrolizumab, the study will evaluate changes in the tumor microenvironment and the antitumor activity of both monotherapy and combination therapy. For more information visit clinicaltrials.gov identifier NCT03674567.

Keytruda is a registered trademark of Merck Sharp and Dohme Corp, a subsidiary of Merck and Co., Inc., Kenilworth, NJ, USA.

FLX475 is a best-in-class oral, small molecule antagonist of CCR4 which selectively blocks suppressive regulatory T cells in tumor tissue and promotes a durable anti-tumor immune response. 

FLX Bio has completed a study of FLX475 in healthy volunteers, demonstrating that the compound is safe with excellent pharmacokinetic and pharmacodynamic properties. In preclinical studies, FLX475 inhibited tumor growth and increased tumor regression as a single agent.

In addition, FLX475 enhanced the anti-tumor effects of various checkpoint inhibitors as well as immune agonist antibodies.

FLX475 also has the potential to enhance cell-based immunotherapies such as CAR-T and cancer vaccines.

In contrast to depleting antibody approaches, FLX475 selectively blocks the recruitment of regulatory T cells to the tumor site and does not deplete cells beneficial to an anti-tumor response or regulatory T cells in healthy tissue.

FLX Bio, Inc. is a privately-held biopharmaceutical company focused on the discovery, development and commercialization of best-in-class, oral small molecule therapeutics for the treatment of cancers and other immune disorders.

Its lead compounds inhibit the CCR4 pathway which plays a key role in both suppressing the immune response to cancer and in the initiation, progression and persistence of allergic inflammation.