We changed our name to RAPT Therapeutics (formerly FLX Bio) to more accurately represent the company’s unrelenting determination and passionate drive to leverage our expertise in immunology, small molecule drug discovery and computational biology to conquer cancer and allergic inflammatory diseases. The name RAPT Therapeutics embodies our unwavering focus to apply scientific rigor and discipline to advance best-in-class, oral treatments that intelligently target key drivers of the immune system to more effectively and safely combat cancer and allergic diseases, and importantly, improve patients’ lives.
Utilizing our proprietary discovery and development engine, we develop highly selective small molecules that are designed to modulate critical immune responses underlying cancer and allergic inflammatory diseases. We have discovered and advanced two drug candidates each uniquely targeting CCR4. Our lead oncology drug candidate, FLX475, reached the clinic in just 2.5 years and we expect our lead inflammation drug candidate, RPT193, to enter the clinic in the second half of 2019.
Our lead oncology drug candidate, FLX475, selectively inhibits the migration of immunosuppressive regulatory T cells (Treg) into tumors. In a Phase 1 clinical study in 104 healthy volunteers, FLX475 was well tolerated and demonstrated favorable drug like properties with a high level of target engagement. We are currently conducting a Phase 1/2 clinical study investigating FLX475 as a single agent and in combination with pembrolizumab, a PD-1 antibody, in patients with “charged” tumors who we believe have the greatest probability of clinical benefit. We anticipate announcing clinical proof-of-concept data from this study in the first half of 2020.
Our lead inflammation drug candidate, RPT193, is designed to selectively inhibit the migration of type 2 T helper cells (Th2) into allergically-inflamed tissues. Th2 cells are clinically validated driver of allergic diseases such as asthma, chronic urticaria (skin rash), allergic conjunctivitis, rhinosinusitis and eosinophilic esophagitis (inflammation of the esophagus). In multiple preclinical models of allergic inflammation, oral dosing of RPT193 demonstrated activity in reducing inflammation comparable to leading injectable biologics with validated clinical activity. Preclinical toxicology studies demonstrate a safety profile that supports chronic dosing. We believe the preclinical safety and efficacy results combined with the convenience of oral dosing suggest a profile competitive with standard of care, including steroids and dupilumab, as well as clinical-stage drug candidates, such as the JAK inhibitors. We expect to initiate a seamless Phase 1 study of RPT193 comprised of a Phase 1a single and multiple dose escalation cohorts of healthy volunteers in the second half of 2019, followed by placebo-controlled Phase 1b testing in patients with moderate to severe atopic dermatitis.
In addition we are identifying lead compounds that inhibit general control nonderepressible 2 (GCN2), which we believe is a fundamental regulator of antitumor immunity and tumor cell survival. In preclinical studies, our lead molecule has demonstrated the ability to fully restore T cell proliferation and function in nutrient-deprived conditions, enhance tumor cell death and elicit anti-tumor responses. We anticipate filing an IND with the FDA in 2020.
We are also pursuing a range of targets including HPK1 that are in the discovery stage of development.