Exclusive: Former OpenAI exec Fidji Simo discusses her battle with POTS and her startup’s plans to cure it with AI and 3,500 vials of blood (so far)

When Fidji Simo announced she was leaving her role as one of the most senior members of OpenAI’s leadership team after a seven-year battle with her chronic illness, Postural Orthostatic Tachycardia Syndrome, or POTS, the news felt unexpectedly personal. My little cousin has POTS, and it’s been devastating to witness. Simo’s post said she would be focusing on how to use AI to cure these types of diseases, but I wondered if it was just another tech executive making lofty promises about AI that may never materialize.

“Do people like my cousin have any reason to have hope that AI can actually make a difference for their health?” I asked Simo when I reached out to her after the announcement. I also told her how much I admired her courage to be so open about her condition. That’s not easy for a highly scrutinized public figure. Simo was previously at Meta for a decade, where she oversaw the Facebook app, and then served as CEO of Instacart, which she brought public in 2023, before joining OpenAI in 2025. 

“Yes,” she answered. “I created a company, ChronicleBio, to tackle just that.” 

We hopped on the phone to chat about it in Simo’s first interview since leaving her position as OpenAI’s CEO of AGI deployment, where she reported directly to CEO Sam Altman. While now her main focus is her recovery and a never-ending schedule of medical appointments, she’s also working on growing ChronicleBio as well as continuing to advise OpenAI. She’s still in a Slack channel with the company’s leadership team, where she regularly speaks with Altman, and Greg Brockman, the OpenAI cofounder and president who took over the bulk of Simo’s responsibilities when she departed. 

Brockman’s wife, Anna, has POTS in addition to two other chronic diseases. ChronicleBio’s three cofounders—Simo, Rohit Gupta, and Rishi Reddy—also either have chronic diseases themselves, or have a family member with one. These days, Simo says she’s “physically the worst I’ve ever been.” There is no cure for POTS. It causes dizziness upon standing up, fatigue, brain fog, headaches, and other symptoms, owing to an imbalance in the body’s autonomic nervous system.

Chronic conditions are “becoming a real epidemic,” Simo tells me. “We’re talking about hundreds of billions in lost productivity, and so there’s very big potential in finding drugs for these conditions.” 

In its first year as a company, ChronicleBio has performed 890 blood draws from 709 patients in Utah, Arizona, Texas, and India. It has over 3,500 tubes of blood in its “biobank,” the company tells me. It’s extracted 153 terabytes of data from the blood—that’s three times the 45 terabytes GPT-3.5, a 2022 model from OpenAI, was trained on. The company has raised $15 million to date. 

The next big thing: home blood draws. On Aug. 11, ChronicleBio will launch a sign-up link for mobile phlebotomy trucks to come to the homes of people with certain chronic diseases. Participants will get an in-depth report on their........

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