A Menlo Park biotech led by former Instacart and OpenAI executive Fidji Simo has closed a multi-tranche seed round to bring precision medicine tools to conditions like chronic fatigue syndrome and long COVID.
ChronicleBio has pulled together $15 million as of early August 2026 from investors including Tarsadia Investments and Electric Capital, Fortune has reported. The company is betting that whole-genome sequencing, epigenetics, RNA analysis, immune profiling, proteomics and metabolomics can reveal biologically distinct subtypes hidden within broad diagnostic labels.
The approach sounds technical because it is. ChronicleBio calls it "multi-omic endotyping." The premise: conditions like postural orthostatic tachycardia syndrome, or POTS, may not be single diseases but clusters of mechanistically different illnesses that happen to produce identical symptoms. Find the right biomarker, the thinking goes, and you turn a coin-flip drug response into something closer to a certainty.
"The right biomarker turns a 20% response rate into a 70% response rate," John Mumm, the company's chief scientific officer, said when he joined ChronicleBio. Mumm founded Deka Biosciences and was part of the team at ARMO BioSciences before Eli Lilly paid $1.6 billion for it in 2018. He has also logged time at Merck, MedImmune and Schering-Plough.
During its first year, ChronicleBio conducted 890 blood draws from 709 patients across Utah, Arizona, Texas and India, according to Fortune. The startup built a biobank containing thousands of samples and extracted what it describes as roughly 153 terabytes of molecular data. The company has said it identified five sub-diseases within POTS alone, each with different underlying biology despite presenting with the same clinical picture.
That scale of data collection reflects both ambition and necessity. These conditions have resisted clean biological explanations for decades, in part because research funding has flowed elsewhere. ChronicleBio formed a research partnership with Solve M.E., the Brain Inflammation Collaborative, the Complex Disorders Alliance and CareEvolution to accelerate work on myalgic encephalomyelitis/chronic fatigue syndrome, long COVID and related neuroimmune disorders.
Simo's involvement brings a rare mix of operational heft and Silicon Valley credibility to a corner of medicine that has often struggled for legitimacy. She took Instacart public in 2023 after running the Facebook app at Meta, and served as CEO of AGI Deployment at OpenAI until July 2026 before turning her attention to biotech. CEO Rohit Gupta served as UCSF's first Chief Biobank Officer starting in 2019 and previously launched Stanford Biobank. Executive Chairman Rishi Reddy is a managing director at Tarsadia, which also has a board seat through Jay Santoro, according to Equilar ExecAtlas.
The company's investor base tilts toward tech-oriented funds willing to wade into life sciences. Electric Capital, better known for crypto bets, joined a round that also included a women's health-focused vehicle. That mix suggests ChronicleBio is pitching a story about data infrastructure as much as drug development.
AI-driven drug discovery has drawn steady capital in recent years. Converge Bio, for instance, raised $25 million in a Series A round in January 2026, TechCrunch reported. ChronicleBio is positioned slightly differently: less about generating novel molecules, more about figuring out which patients should receive which existing therapies.
The company plans to test existing drugs on stratified patient subgroups by the end of 2026, Simo told Fortune. ChronicleBio offers mobile phlebotomy to accommodate bedridden patients and returns results to participants, a nod to the patient-advocacy roots of chronic illness research. "Entire communities of patients have been ignored for too long," Simo said when the company launched. "We aim to accelerate the path to cures."
Whether the multi-omic bet pays off remains an open question. The science is promising but unproven at scale, and the regulatory pathway for biomarker-driven patient stratification can be thorny. Still, ChronicleBio has assembled the kind of team and backing that suggests someone thinks the odds are better than a coin flip.
