FLX Bio isn’t the biotech it started out to be.
Formed as a spinout of Flexus after Bristol-Myers Squibb stepped in to buy the fledgling and an early-stage IDO1 therapy for the jaw-dropping sum of $1.25 billion, the biotech went on to pursue a FLT3/CDK4/6 drug for cancer. 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.
Today, the South San Francisco-based biotech is taking the wraps off a $60 million round to complete the makeover, bringing its total raise in just two years to a hefty $139 million with the help of GV (read Google) along with The Column Group, Kleiner Perkins, Topspin Partners and Celgene Corporation.
Their old lead “just didn’t get there” on safety and efficacy, says chief medical officer William Ho, which didn’t cut it in a competitive field. But Ho and his colleagues now believe that the biotech’s oral CCR4 antagonist has a much better shot at success.
“Our program we believe is definitely best in class and quite different from the other programs,” asserts COO Rekha Hemrajani.
Oncology specialists will recall that Kyowa Hakko recently unveiled positive Phase III data for their anti-CCR4 therapy mogamulizumab, which has been dispatched for review at the FDA with positive progression-free survival. But FLX is in the business of making what it believes is a better small molecule drug that can have a much more targeted effect.
Any antibody targeting CCR4 will likely have serious safety issues, they say, taking a sledgehammer approach to T cells to their scalpel.
The strategy here is that a small molecule drug can prevent regulatory T cells from entering a tumor identified by the expression of ligands, potentially amping up immunotherapies like PD-1/L1 and CTLA4 checkpoints. And like a lot of players in this field, FLX is lining up a checkpoint therapy for a combo approach.
FLX is hoping to have some clear data highlighting their drug’s anti-tumor potential in 2019.
Ho says it can be a challenge mounting cancer studies these days, with hundreds of drugs and combinations competing for patients. That will require FLX to do everything it can to stand out from the crowd to win over the investigators and sites considering which therapies to test first.
The challenge also makes it more important for them to come up with a seamless development strategy, moving from healthy volunteers into patients to dose escalation and expansion cohorts with a combination. And the biotech also believes it may be able to pursue a basket approach, taking a tumor agnostic strategy that would allow them to test the drug in any patient that met the right ligand profile.
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