Absci Corporation reported positive interim Phase 1 data from its first-in-human trial of ABS-201, an investigational anti-prolactin receptor (PRLR) antibody, demonstrating favorable safety and tolerability across all blinded single ascending dose (SAD) cohorts. The study estimated a half-life of at least 65 days, supporting a potential dosing interval of two or three injections over a six-month period. Interim proof-of-concept data is anticipated in the second half of 2026, with full proof-of-concept data expected in early 2027.

The Phase 1 trial (NCT07317544) is an ongoing, randomized, double-blind, placebo-controlled study evaluating the safety and pharmacokinetics of ABS-201 in healthy volunteers with and without androgenetic alopecia (AGA). The interim data comprise 32 healthy adult participants enrolled in four planned SAD cohorts, with dose levels of 150 mg, 450 mg, 900 mg, and 1800 mg administered intravenously (IV). Following review by the trial’s Safety Review Committee, the study has advanced into the subcutaneous multiple ascending dose (MAD) portion in participants with AGA.

Blinded, aggregate interim safety data indicate that ABS-201 was well tolerated, with no serious adverse events reported as of the June 8, 2026 data cutoff. All treatment-emergent adverse events (TEAEs) were mild in severity, except for a single moderate TEAE (headache) in SAD cohort 3, assessed as unlikely related to study treatment. Treatment-related TEAEs were reported in five participants and were all mild. Headache was the most frequently reported TEAE across cohorts, occurring in four participants.

Pharmacokinetic (PK) data across all four SAD cohorts, including Day 56 follow-up in lower-dose cohorts, indicate a half-life of at least 65 days for ABS-201. These results support the potential for dosing two or three times over a six-month period, pending confirmation through continued follow-up. Immunogenicity data showed no apparent impact of anti-drug antibodies (ADAs) on PK based on interim data in the SAD cohorts.

ABS-201 is a novel therapeutic approach targeting prolactin receptors to stimulate hair follicle regeneration and promote durable hair regrowth, as demonstrated in preclinical studies. The antibody showed statistically significant superior hair regrowth compared to minoxidil in a preclinical mouse model. Absci anticipates initiating a Phase 2 trial for endometriosis later this year. The HEADLINE trial is designed to enroll up to 227 healthy adult volunteers across SAD and MAD cohorts, with primary endpoints of safety and tolerability.