Google-Backed FLX Bio Scores $60M Financing

FLX Bio completed a $60 million Series C financing. New investors included GV (formerly Google Ventures) and undisclosed investors. Existing investors included The Column Group, Kleiner Perkins, Topspin Partners and Celgene Corporation. The raise makes for a total of $139 million in two years.

The company also indicated it had dosed its first patient in a Phase I clinical trial of FLX475, the company’s oral small molecule antagonist of CCR4. This is a dosing and safety study in healthy volunteers, before testing will occur in cancer patients.

"We are pleased to move our lead program forward into the clinic," said Bill Ho, FLX Bio’s chief medical officer, in a statement. "Regulatory T cells are highly potent suppressors of the adaptive immune response and their presence in most tumors are correlated with a poor prognosis. With very few agents in development selectively inhibiting these cells, we believe targeting CCR4 represents a differentiated and exceptionally promising approach to treating cancer."

FLX Bio was a spinout of Flexus when Bristol-Myers Squibb acquired Flexus Biosciences in 2015 for $1.25 billion. John Carroll, writing for Endpoints News, says, "Then the founders—Terry Rosen and Juan Jaen—left to start their own companies and the new crew at FLX wound up terminating their original lead drug earlier this year and switching focus to another target in oncology: CCR4, focused on regulatory T cells."

They were originally focusing on FLT3/CDK4/6, but the safety and efficacy of their compound wasn’t good enough to compete in a very competitive field. Rekha Hemrajani, FLX Bio’s chief operating offer, told Carroll, "Our program we believe is definitely best in class and quite different from the other programs."

The company hopes to have data on the drug’s efficacy in 2019.

"With a discerning syndicate of investors committed to our science, our strategy and our team, we look forward to using the proceeds of this Series C financing to advance our robust pipeline of small molecule immuno-oncology compounds focused on regulatory T cell and tumor myeloid cell modulation," said Brian Wong, FLX Bio’s president and chief executive officer, in a statement. "In addition to initiating Phase I testing for our lead molecule FLX475, a highly potent and selective oral CCR4 antagonist for the treatment of cancer, we intend to select a clinical candidate targeting USP7 and continue advancement of our GCN2 program, with all three programs representing differentiated and important mechanisms to stimulate an immune response within the tumor microenvironment."

CCR4 is a protein expressed on regulatory T cells. Regulatory T cells work to prevent autoimmune diseases and control inflammation, but cancer cells can commandeer this activity by recruiting numerous regulatory T cells to a tumor site, what is called the tumor microenvironment. Within this environment, regulatory T cells keep the body from having an immune response against the tumor cells, which allows cancer to go unchecked. Tumors do this recruitment by emitting chemicals, CCL17 and CCL22, which bind to CCR4. FLX475 inhibits CCR4, which stops the regulatory T cells from migrating to the tumor microenvironment.