Phase 2 trial: Topical STS01 shows dose-related hair regrowth in mild-moderate alopecia areataTopical treatment shows hair regrowth in alopecia areata, but quality of life unchanged

medRxiv Published April 4, 2026 Study authors: Fleet, D. M.; Messenger, A.; Bryden, A.; Harris, M. J.; Holmes, S.; Farrant, P.; Leaker, B.; Takwale… DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Consider that hair regrowth with topical STS01 may not correlate with HRQoL improvement in alopecia areata.

A Phase 2 randomized controlled trial evaluated the topical formulation STS01 (dithranol/ProSilic) versus placebo in patients with mild to moderate patchy alopecia areata. The study found significant and dose-related improvements in hair regrowth with STS01 treatment. However, this clinical benefit did not lead to significant improvements in health-related quality of life (HRQoL) as measured by the Alopecia Areata Symptom Impact Scale (AASIS), even among patients who achieved complete hair regrowth. The analysis noted some treatment-related correlation between AASIS score changes and Severity of Alopecia Tool (SALT) scores.

Safety and tolerability data were not reported in the available evidence. The study's limitations include potential issues with establishing a true baseline at patient entry, the development of patient coping mechanisms that may affect HRQoL reporting, and a possible delay between physical and psychological improvement. The researchers also noted challenges with HRQoL measurement in this population.

As a Phase 2 trial, these results are preliminary and specific to patients with mild to moderate patchy disease. The dissociation between objective hair regrowth and patient-reported HRQoL outcomes highlights the complexity of assessing treatment benefit in alopecia areata. Further research is needed to confirm efficacy, establish safety, and better understand the relationship between clinical endpoints and patient experience.

Researchers conducted a Phase 2 clinical trial to test a topical treatment called STS01 for people with mild to moderate patchy alopecia areata. The study was designed to see if the treatment could help hair grow back and if that regrowth improved how patients felt about their daily lives and symptoms.

The trial found that the treatment did lead to significant hair regrowth, and the effect was stronger with higher doses. However, even in patients who had complete hair regrowth, there was no significant improvement in their self-reported quality of life, which was measured by a symptom impact scale. The study authors noted that patients may develop coping mechanisms or that there could be a delay between physical and emotional improvement.

This was an early-stage (Phase 2) study, so the results are not final. The main reason for caution is that while the treatment showed a clinical benefit for hair growth, it did not translate into a measurable improvement in how patients felt. Readers should understand that this research is still in progress, and larger, longer studies are needed to fully understand the treatment's effects and its impact on a person's well-being.

What this means for you:

Early trial shows hair regrowth from a topical treatment, but patients' quality of life scores did not significantly improve.

Study Details

Study typeRct

EvidenceLevel 2

PublishedApr 2026

View Original Abstract ↓

A phase 2, randomised, double-blind, placebo controlled trial has been conducted in mild to moderate patchy alopecia areata (AA). This demonstrated significant and dose related improvements in hair regrowth with STS01, a controlled release, topical formulation of dithranol. Here we report the results of the Alopecia Areata Symptom Impact Scale (AASIS) that assesses the severity of symptoms, daily functioning and feelings. Similar to trials in severe AA, significant improvements in hair regrowth did not translate into significant health-related quality of life (HRQoL) improvements, even in patients with complete hair regrowth, although there was some treatment-related correlation between changes in AASIS scores from baseline and clinical assessment SALT scores. The use of current HRQoL methods or indeed new measures in development for future trials, will have considerable challenges: patients may not have a true baseline at entry, may develop coping mechanisms, and there may be a delay between physical and psychological improvement.

Phase 2 trial: Topical STS01 shows dose-related hair regrowth in mild-moderate alopecia areataTopical treatment shows hair regrowth in alopecia areata, but quality of life unchanged

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Phase 2 trial: Topical STS01 shows dose-related hair regrowth in mild-moderate alopecia areataTopical treatment shows hair regrowth in alopecia areata, but quality of life unchanged

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