This Former OpenAI Exec Is Trying To Cure Chronic Diseases, Including Her Own

In May 2025, Fidji Simo started her dream job at OpenAI as Sam Altman’s second-in-command. But as she ramped up her work as chief executive of applications and then of AGI deployment, privately she was suffering from a devastating health condition.

She’d been diagnosed six years earlier with postural orthostatic tachycardia syndrome, or POTS, a frustrating chronic condition in which moving from lying down to standing, or even to sitting up, can cause a racing heart and dizziness. But after starting at OpenAI, her condition worsened, and she found she could no longer keep up with the frenetic schedule the AI startup demanded. This July, Simo stepped down from the company, though she remains an adviser there.

“Unfortunately, it’s very, very hard for me to stand without passing out. I can’t sit or stand so long—more than five or 10 minutes, I pass out, which is very inconvenient to say the least,” she says.

For the last year, Simo, 40, has been working on ways to use AI to attack chronic health conditions like her own. In March 2025, while still at OpenAI, she launched a startup called ChronicleBio with Rohit Gupta, who had previously overseen biobanks at Stanford and UCSF, and Rishi Reddy, a managing director at Tarsadia Investments. While Simo is a cofounder, Gupta is the company’s CEO. Reddy, whose firm gave the company a few million dollars as its first seed funding, is executive chairman.

Their goal: To sort through the thicket of symptoms underlying chronic immune-related diseases like POTS, long COVID and myalgic encephalomyelitis/chronic fatigue syndrome, known as ME/CFS (the term “chronic fatigue syndrome” has fallen out of favor for trivializing and stigmatizing a debilitating health condition). Taken together, perhaps 250 million worldwide suffer from this set of chronic conditions, Gupta estimates.

“I don’t think any three people want to solve this problem more than we do."

“We think these conditions are names that doctors have put on symptoms."