No new biological mechanism for hair loss has been FDA-approved in nearly thirty years. That may be changing with ABS-201, an AI-designed antibody targeting the prolactin receptor.
The same two drugs—finasteride and minoxidil—have dominated the hair loss treatment category for decades. Finasteride blocks DHT. Minoxidil boosts scalp blood flow. Both help some people. But neither have moved the needle much for the millions of Americans living with pattern hair loss.
Now the industry is betting that a new mechanism could potentially change things. Eli Lilly led a $100 million underwritten offering in Absci, a company developing an AI-designed antibody for pattern hair loss. The late June raise was joined by Adage, BVF Partners, Columbia Threadneedle, Invus, and Redmile.
Absci says it used generative AI to design ABS-201. But ABS-201 isn’t the first to emerge from AI-powered drug design. Other companies have pursued AI-designed molecules in clinical testing. However, ABS-201 is among the farthest AI-generated antibody therapeutics in human trials. It is currently in a Phase 1/2a trial for androgenetic alopecia. The company announced plans to launch a Phase 2 trial for endometriosis later this year.
With the prolactin pathway showing potential, Absci CEO Sean McClain told Fortune the company plans to cut development costs and timelines by running global clinical studies in China. In their filing, the company said that the $100 million capital will fund ABS-201 development for both pattern hair loss and endometriosis.
The raise from Lilly and other investors signals confidence in the prolactin mechanism and program potential. But how much is actually known about prolactin biology?
Prolactin is a non sex hormone that influences tissue remodeling and cell signaling throughout the body. But the science behind it and hair isn’t new. Researchers began studying prolactin regulation in the 1950s. But for over fifty years, the connection to hair loss went largely unexplored.
That changed in 2006 with a landmark study published in the American Journal of Pathology. Researchers discovered that hair follicles both produce prolactin and respond to it. Hair follicles make prolactin, and then the hormone signals the follicles to shift out of their growth phase.
Preclinical research suggests prolactin may act as a critical regulator. This essentially means it could be a switch that accelerates hair regression, the process where active follicles shift into the shedding phase. ABS-201 is designed to block prolactin receptors to potentially prolong the follicle growth phase and thicken hair.
Absci released positive interim Phase 1 safety data from HEADLINE, its clinical trial for ABS-201, in June. The data showed no serious safety events in early cohorts. Still, it’s early to get a full picture of safety or whether blocking the prolactin receptor will produce the same meaningful hair growth in humans as it did in macaque monkeys. That will be answered as the trial progresses. But the company seems to be betting its future on prolactin.
Absci’s CMO Ransi Somaratne suggested the company sees potential for blocking prolactin signaling beyond hair loss and endometriosis. “The more we look, the more we see prolactin playing a key role in disease processes beyond hair loss and endometriosis,” Somaratne told Clinical Trial Arena. The company hasn’t detailed which other conditions it’s exploring.
Absci is not alone in pursuing prolactin as a therapeutic target. Swedish biotech BioInvent originally developed the prolactin receptor antibody HMI-115 in collaboration with Bayer. In 2019, Bayer transferred the drug’s rights to Hope Medicine, which has since advanced HMI-115 into Phase 2 trials for hair loss.
Speaking on the Hair Loss Insider Podcast, McClain said ABS-201 differs because the AI model optimized the antibody for receptor occupancy—a technical measure that links dosing more directly to biological effect. If that approach is validated in the clinic, it could influence not only hair loss treatment but also the broader development of therapeutic antibodies.
For now, the full effects are still being determined.
