Flexus Biosciences

Notes

Flexus Biosciences was a biotechnology company focused on immuno-oncology therapeutics, specifically developing small molecule inhibitors of indoleamine 2,3-dioxygenase 1 (IDO1), an enzyme that tumors use to suppress the immune system.

Acquired by Bristol-Myers Squibb in February 2015 for $800 million upfront plus up to $450 million in milestones (total potential value $1.25 billion). This was one of the largest acquisitions in the immuno-oncology space at the time.

The company's lead compound BMS-986205 (formerly F001287) advanced into clinical trials with Bristol-Myers Squibb and was tested in combination with checkpoint inhibitors like Opdivo (nivolumab). However, IDO inhibitors as a class faced setbacks after Incyte's epacadostat failed in Phase 3 trials in 2018, leading to reduced development activity across the industry.

Team (Pre-Acquisition)

• Juan Jaen, Ph.D. - CEO & Co-founder
  • LinkedIn: linkedin.com/in/juanjaen
• David Wustrow, Ph.D. - Chief Scientific Officer & Co-founder
• Terry Rosen, Ph.D. - Board member (Arcus Biosciences CEO)

Additional Research Findings

• Founded in 2013 in San Carlos, California
• Acquired by Bristol-Myers Squibb in February 2015
• Deal valued at $800 million upfront + $450 million in milestones
• Lead compound was IDO1 inhibitor (later BMS-986205)
• Backed by Kleiner Perkins, 5AM Ventures, and others
• Raised approximately $38 million before acquisition
• IDO inhibitor class faced industry-wide setbacks after 2018 clinical failures

Sources

• Bristol-Myers Squibb Acquisition Press Release (2015)
• Crunchbase Profile
• FierceBiotech Coverage