Next Generation Oral Drugs for Cancer

FLX Bio is developing a pipeline of orally-available small-molecule drugs to activate the immune system and eradicate cancer.  The potential advantages of the FLX Bio small-molecule approach to immuno-oncology (IO) treatments include the convenience of oral dosing, the ability to more easily control the clinical effects of treatment to achieve an ideal balance of efficacy and safety, and the ability to target a broader range of immune system targets, including intracellular proteins and pathways.

“Immune-targeted therapies are already impacting the lives of patients afflicted by a growing number of cancer types. Modulation of tumor-infiltrating regulatory T cells represents a promising unexploited therapeutic approach, creating the opportunity to complement, and work in combination with, the growing list of immune checkpoint inhibitors and other non-immunological therapeutic modalities.”

—Alexander Rudensky, Ph.D., Chairman, FLX Bio SAB

Discovery Targets


The field of immuno-oncology (IO) is just beginning to show the life-changing impact possible through immune-based interventions. FLX Bio is developing best-in-class, small molecule IO therapeutics to improve patients’ lives.

The human immune system protects the body from threats, external and internal, by distinguishing foreign from self. Using a mechanism called “immune surveillance,” the immune system recognizes and kills tumor cells that arise in the body. However, when immune surveillance fails, cancer can develop. For over a century, researchers have tried to boost the immune response to fight cancer. Though earlier interventions had limited efficacy and significant toxicity, the recent use of checkpoint inhibitors such as anti-CTLA-4 and anti-PD-1/PD-L1 antibodies, also known as checkpoint inhibitors, has resulted in deep and durable antitumor immune responses in multiple types of cancer. While this progress in the IO field has positively impacted a proportion of cancer patients, additional efforts are needed to improve the lives of even more people.

In the IO space, FLX Bio is focusing on a critical area of the antitumor immune response that has so far been neglected, that of suppressive cells in the tumor microenvironment. The tumor microenvironment is the local environment in which the tumor occupies. Both antitumor and immune-suppressive cells are recruited to the tumor microenvironment, but in growing tumors, an antitumor effect isn’t observed because the balance favors tumor growth. Our goal is to inhibit the immune-suppressive cells within the tumor microenvironment, tipping the balance in favor of the immune system attacking the tumor, while limiting the immune attack on healthy tissues. The primary cells that interfere with the immune system’s ability to execute an effective antitumor response include regulatory T (Treg) cells and myeloid cells including myeloid-derived suppressor cells (MDSCs).

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