After $700M-plus Merck buyout, Tilos CEO Fox lands at Rheos Medicines

Barbara Fox takes over from interim CEO Abbie Celniker, Ph.D., a partner at Third Rock Ventures, which launched Rheos with $60 million in March 2018. (Pixabay)

Barbara Fox, Ph.D., is getting right back on the horse. Fresh off Tilos Therapeutics’ $773 million sale to Merck, Fox is taking the helm of another Cambridge, Massachusetts-based company: Rheos Medicines. 

Fox takes over from interim CEO Abbie Celniker, Ph.D., a partner at Third Rock Ventures, which launched Rheos with $60 million in March 2018. Celniker ceded the reins last September when Third Rock poached Dr. Sanjay Keswani from Roche, but took them up again this July when Keswani headed to Annexon Biosciences to become its chief medical officer. 

“We are delighted to welcome Barbara to the team and believe her track record makes her an ideal fit as Rheos Medicines’ Chief Executive Officer,” Celniker said in a statement. “We are confident that Barbara’s expertise in building and leading organizations will be an indispensable asset for Rheos and will propel the Company as it develops precision medicines for autoimmunity and other immune-mediated diseases.” 


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RELATED: Third Rock launches Rheos, puts $60M behind immunometabolism player 

A chemist by training, Fox started her industry career at ImmuLogic before becoming chief scientific officer at Recovery Pharmaceuticals. She led Avaxia Biologics as its founder and CEO and spent time at Partners Innovation Fund as an entrepreneur-in-residence before landing at Tilos. 

Fox will pivot from her previous work developing antibody-based treatments for cancer and immune-mediated diseases to lead Rheos’ work on what it calls metabolism-tuning therapies. It’s aiming at the same therapeutic buckets Tilos did—autoimmune disease and cancer—but doing so by targeting metabolic pathways in immune cells that are linked to disease and “re-tuning” the immune responses that go awry in those diseases. 

“Rheos Medicines is pioneering and industrializing the emerging field of immunometabolism, and I am thrilled to be joining at such a pivotal time in the Company’s evolution,” said Dr. Fox. “Rheos’ scientific founders and passionate scientists are leaders in the field, and their groundwork has established an incredible foundation on which to build upon. I look forward to working with the Rheos team as we leverage the Company’s proprietary immunometabolism product engine to unlock a new frontier in drug discovery.” 

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