Interim Trial Results and Preclinical Data Highlight Potential of ABS-201 in Androgenetic Alopecia

The investigational antibody ABS-201 showed a favorable preliminary safety profile and pharmacokinetic characteristics in the single-ascending-dose portion of a first-in-human phase 1/2a trial, while preclinical poster data provide additional support for its proposed mechanism in androgenetic alopecia (AGA).¹ The findings were reported by Absci alongside interim clinical data from the ongoing HEADLINE trial (NCT07317544).²

“We are particularly encouraged by the emerging safety, pharmacokinetic, and immunogenicity profile observed to date," Ransi Somaratne, MD, Chief Medical Officer of Absci, said in the press release. "We look forward to further characterizing ABS-201’s clinical profile and potential in the ongoing MAD portion of the HEADLINE trial for AGA, and to initiating a phase 2 trial for endometriosis later this year.”¹

Infrequent Dosing and Tolerability Findings

The randomized, double-blind, placebo-controlled phase 1 study enrolled 32 healthy adults across 4 single-ascending-dose cohorts. Participants received 150, 450, 900, or 1800 mg of ABS-201 or matched placebo intravenously, with a 3:1 randomization within each cohort. Blinded interim safety data through June 8, 2026, showed no serious adverse events. Treatment-emergent adverse events were generally mild, with one moderate event (a headache in the 900-mg cohort) that was considered unlikely to be related to treatment. Treatment-related adverse events occurred in 5 participants and were all mild. Headache was the most frequently reported adverse event, occurring in 4 patients.

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Interim pharmacokinetic data indicated an estimated half-life of at least 65 days, although continued follow-up is needed to confirm the duration. The pharmacokinetic profile supports the possibility of dosing 2 or 3 times over a 6-month period. No apparent effect of treatment-emergent anti-drug antibodies on pharmacokinetics was observed in the single-dose cohorts. Based on review of the blinded safety and pharmacokinetic data, the trial has progressed to its multiple-ascending-dose portion, in which participants with AGA are receiving subcutaneous ABS-201.

Poster Data: A Prolactin-receptor Mechanism

The accompanying poster, presented at the 2026 American Academy of Dermatology Innovation Academy in New York, New York, demonstrated mechanistic findings from human scalp hair follicle and organ-culture models. ABS-201 is an antibody designed to block prolactin receptor (PRLR) signaling. According to the poster, human scalp follicles express both prolactin and PRLR, and local prolactin signaling can suppress hair shaft elongation and promote premature entry into catagen. In ex vivo human scalp models, ABS-201 blocked prolactin-induced PRLR-STAT5 signaling and reduced the prolactin-associated shift toward catagen. The antibody also increased markers of hair matrix proliferation and reduced apoptosis.

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Additional findings suggested preservation of the hair follicle stem and progenitor cell compartment. ABS-201 reduced prolactin-induced apoptosis in K15-positive bulge cells and helped preserve CD34-positive progenitor and CK19-positive epithelial stem-cell populations. The poster also reported restoration of anagen-associated growth factor signaling, including IGF-1 and FGF7, along with changes in keratin expression consistent with improved hair shaft production and follicular integrity. RNA sequencing and pathway analyses further showed that ABS-201 attenuated prolactin-induced inflammatory signaling and restored hair follicle remodeling programs. The investigators concluded that the findings provide biological proof of concept for targeting PRL-PRLR signaling in AGA, although clinical efficacy remains to be established.

Conclusion

The HEADLINE trial is designed to enroll up to 227 healthy volunteers and patients with AGA. The multiple-ascending-dose portion is evaluating 300-, 600-, and 1200-mg subcutaneous doses, with hair-growth assessments planned at 13 and 26 weeks. Secondary endpoints include target-area hair count, target-area hair width, and target-area hair darkening or pigmentation, in addition to pharmacokinetic, pharmacodynamic, immunogenicity, and patient- and investigator-reported outcomes.

Interim proof-of-concept findings are anticipated in the second half of 2026, with full proof-of-concept data expected in early 2027. The ongoing multiple-dose study will provide the first clinical assessment of whether the mechanistic effects observed in ex vivo human follicles translate into measurable hair regrowth in patients with AGA.

References

1. Absci Announces Positive Interim Phase 1 Data from the HEADLINE™ Trial of ABS-201, a Novel Antibody Targeting the Prolactin Receptor (PRLR). News release. Absci. Published June 24, 2026. Accessed August 6, 2026. https://investors.absci.com/news-releases/news-release-details/absci-announces-positive-interim-phase-1-data-headlinetm-trial

2. Chéret J, Gherardini J, Kothari V, et al. ABS-201, an AI-designed Antibody, Blocks Prolactin–PRLR Signaling and Presents a Novel Biologic Strategy for the Treatment of Androgenetic Alopecia. Poster presented at the 2026 American Academy of Dermatology Innovation Academy; July 16-19, 2026; New York, New York.