FLX Bio keeps it capital in RAPT Therapeutics rebrand

When Bristol-Myers Squibb bought Flexus Biosciences, FLX Bio emerged with immuno-oncology programs the Big Pharma didn’t want and a name inspired by its parent. Now, the biotech is renaming itself RAPT Therapeutics to reflect its expansion into allergy and inflammatory diseases.

“The name RAPT Therapeutics embodies our commitment to apply our proprietary discovery and development engine to advance highly selective, oral treatments that intelligently target key immune drivers to more effectively and safely treat cancer and inflammatory diseases, and importantly, improve the lives of patients,” said Brian Wong, M.D., Ph.D., CEO of the newly renamed company, in a statement.

The Bay Area biotech picked up $60 million in series C financing in December 2017 to advance its lead asset, an oral CCR4 inhibitor dubbed FLX475. The hope is that, by blocking CCR4, the drug can disrupt a pathway that tumors use to recruit regulatory T cells—called Tregs—and tamp down their immune response to the tumor.

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At the time, the company planned to pick out a second clinical candidate targeting the enzyme ubiquitin specific protease 7 (USP7), which plays a role in two cancer pathways. But FLX, now RAPT, went in a different direction.

“Since our founding, we have internally discovered and advanced two unique drug candidates that target CCR4, with FLX475 in development for the treatment of multiple cancers and RPT193 expected to enter clinical studies in the second half of 2019," Wong said.

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Unlike FLX475, which focuses on Tregs, the inflammation candidate RPT193 takes aim at helper T cells. Tregs suppress other immune cells to shut down the immune response—for example, to prevent autoimmune disease—while helper T cells activate other immune cells. RPT193 is designed to block the movement of type 2 helper T cells into inflamed tissues and reduce inflammation in diseases such as asthma, rhinosinusitis and atopic dermatitis. RAPT plans to file an IND for the drug by the end of the year.

In addition to investigating other cancer targets, RAPT will keep working on a cancer program against general control nonderepressible 2 (GCN2), which plays a role in antitumor immunity and tumor cell survival. It expects to file an IND next year.