FLX Bio treats first patient in its Phase 1/2 clinical trial of FLX475 for treating various advanced cancers

FLX Bio, Inc., a clinical-stage, biopharmaceutical company focused on the development of oral small-molecule drugs that target drivers of cancer and other immune-related disorders, today announced that the first patient has been treated in its Phase 1/2 clinical trial of FLX475 in patients with various advanced cancers. FLX475 is an oral, small molecule CCR4 antagonist that selectively inhibits migration of regulatory T (T_reg) cells into the tumor microenvironment.

"The dosing of our first patient with FLX475 is a significant milestone for FLX Bio as we continue to advance our novel therapeutic approach targeting the tumor microenvironment," said Brian Wong, M.D., Ph.D., CEO of FLX Bio. "T_reg cells play fundamental roles in inhibiting the immune response to the tumor and are a major resistance mechanism to many cancer immunotherapies including PD-1 inhibitors. FLX475 represents a best-in-class approach to selectively decrease T_reg numbers in the tumor thereby unlocking the antitumor immune response. In addition, our big data and proprietary informatics platform has revealed the tumor types most likely to respond to FLX475. We are excited to evaluate this new therapeutic modality in these enriched patient populations through our ongoing global Phase 1/2 clinical trial."

"FLX475 has demonstrated an excellent safety, pharmacokinetic and pharmacodynamic profile in a recently-completed study of healthy volunteers and we believe this compound holds tremendous promise for directly addressing the suppressive effects of T_reg in the tumor microenvironment," said Bill Ho, M.D., Ph.D., Chief Medical Officer of FLX Bio. "Treatment with FLX475 should allow the selective blocking of tumor-associated T_reg recruitment while sparing normal tissues and beneficial cells. This may offer a safer and more efficacious treatment alternative for patients with many different types of cancer, as compared to the several existing strategies used to suppress or deplete T_reg cells."

The open-label, dose-escalation and cohort expansion Phase 1/2 study will enroll patients with multiple types of cancer at leading cancer centers across the United States, Australia and Asia. The trial will evaluate the safety and tolerability of FLX475 as a monotherapy and in combination with pembrolizumab. In addition, the study will evaluate changes in the tumor microenvironment and the antitumor activity of both monotherapy and combination therapy. Patients with tumors positive for the Epstein-Barr Virus (EBV), which has been shown to be an indicator of tumors with a higher number of T_reg cells, will be enrolled in a biomarker-selected cohort. Tumors that can be positive for EBV include nasopharyngeal cancer and Hodgkin lymphoma. In addition, the company intends to enroll patients with tumors that express high levels of CCR4 receptor and ligands, which include non-small cell lung cancer, head and neck cancer, triple negative breast cancer, and cervical cancer. For more information please visit clinicaltrials.gov identifier NCT03674567.