Ari Brettman

Ari Brettman is a Senior Managing Director in Blackstone Life Sciences, based in Cambridge, Massachusetts. He is a physician-investor who joined Clarus Ventures (a life sciences VC firm) in September 2014 and became part of Blackstone in December 2018 when Blackstone acquired Clarus to form the core of its Life Sciences platform. He focuses on investments across the firm's portfolio, including company creation, startups, and structured partnerships with pharmaceutical companies.

Dr. Brettman earned his A.B. in History and Science from Harvard College (2004) and his M.D. from Duke University (2008). During medical school he was a Sarnoff Cardiovascular Research Foundation Fellow at Stanford University. He completed his internal medicine residency and a cardiology fellowship at Massachusetts General Hospital, along with an NIH-sponsored post-doctoral fellowship at the MGH Center for Systems Biology, where his research spanned areas such as autophagy of lipid droplets and electronic medical record–based "big data" analytics.

His clinical and scientific training feeds directly into a hands-on investing style: at Anthos Therapeutics — the cardiovascular company launched by Blackstone Life Sciences and Novartis — he was a founding board member and also served as Acting Chief Medical Officer in the company's early days. He has held or holds directorships across several Blackstone/Clarus portfolio companies.

Note on the "Angel Investor / Seed Round" label carried in some aggregator databases: this appears to be a mischaracterization. Brettman invests through Blackstone's institutional life sciences vehicles, not as a personal seed-stage angel. Founders should treat him as an institutional biopharma investor.

• Invests within Blackstone Life Sciences, deploying large, institutional capital into biopharmaceutical drug development rather than writing personal angel checks.
• Emphasis on company creation and de-risked clinical assets — building "newco" therapeutics companies (e.g., Anthos) and backing platform biotechs, often in partnership with large pharma (Novartis) or through spin-outs.
• Therapeutic focus reflected in his board seats: cardiovascular disease, neuropsychiatric/CNS disorders, and oncology.
• As a physician-investor, brings deep clinical development and trial-design judgment; he has spoken publicly on aligning clinical trial design and adaptive development approaches with investment priorities.
• Says "yes" to companies where scientific rigor, a credible clinical-development path, and the ability to advance meaningful medicines intersect with Blackstone's scale of capital.