Lilly bets $494 million on hibernation biology for obesity targets

Eli Lilly has signed a multi-year deal with Fauna Bio, a small biotech in Emeryville, California, to search for new obesity drug targets by studying the genetics of animals that hibernate ^[1][2]. The deal, announced Dec. 21, 2023, gives Fauna Bio an upfront payment, including an equity investment from Lilly, and makes the company eligible for up to $494 million in additional payments tied to preclinical, clinical, and commercial milestones, plus royalties on any resulting products ^[1].

Fauna Bio's technology is called the Convergence AI platform. It looks at genetic data from 452 mammal species, including 65 species that hibernate, to find genes that might protect animals from problems like obesity, diabetes, or heart disease during periods of extreme physiological stress ^[1]. Hibernating animals go through huge swings in body temperature, metabolism, and fat storage each year without the health damage that similar changes would cause in humans. The idea is that whatever protects them could point to new drug targets for people.

The company's core dataset comes from the 13-lined ground squirrel, along with tissue samples from tenrecs and spiny mice, two other animals known for unusual metabolic adaptations ^[1]. Researchers have collected more than 22 distinct tissue types from the squirrel at 13 precise points in its yearly hibernation cycle, generating thousands of transcriptomes, proteomes, and epigenomes and over 22 billion sequence reads ^[1]. That data feeds a graph neural network with roughly 980 million parameters that combines animal and human data to rank candidate genes for drug targeting ^[1].

Fauna Bio CEO Ashley Zehnder said the deal "showcases the power of our Convergence AI platform to rapidly identify novel targets for complex disease areas of high unmet need" ^[1]. Ruth Gimeno, group vice president for diabetes, obesity, and cardiometabolic research at Lilly, said the company is looking forward to working with Fauna Bio's team to "discover more effective treatments for patients with obesity" ^[1]. Industry outlet Endpoints News, which covers biotech deals, noted that Lilly already has multiple obesity drug candidates in mid- and late-stage clinical development built on its existing GIP and GLP-1 drug platform, meaning this hibernation-focused work is a separate, earlier-stage research effort rather than a near-term product ^[2].

Why it matters for patients

This deal is a preclinical research bet, not a new medicine. Fauna Bio and Lilly are still trying to identify gene targets, a step that comes long before any drug candidate is tested in animals or people ^[1]. Even if the hibernation research finds a promising target, turning that into a tested and approved treatment would take years, and most early-stage discovery deals like this one do not lead to an approved drug at all.

For patients currently using or considering GLP-1 medicines such as Ozempic, Wegovy, Mounjaro, or Zepbound, nothing about this partnership changes what is available today or how those existing drugs work. The interest from a large company like Lilly does suggest that obesity drug research is moving beyond the GLP-1 and GIP pathways used in current medicines, toward looking at metabolism from new angles, including how other mammals naturally regulate body weight and energy use ^[1][2].

What happens next

The sources describe the collaboration as multi-year, with payments tied to milestones across preclinical, clinical, and commercial stages ^[1]. No specific dates for moving a target into human testing are given in the available materials, and it is not yet known which genes, if any, will advance out of the discovery phase.