Soterios: Topical STS-01 Hits Phase 2 Efficacy Endpoints for Mild to Moderate Alopecia

Published on: 

New phase 2 trial data show more than double the patients receiving daily STS-01 1% cream achieved ≥30% improvement in SALT scores.

Investigative therapy 1% STS-01 was associated with a more than doubled rate of patients with alopecia areata achieving a ≥30% improvement in Severity of Alopecia Tool (score) versus placebo over 24 weeks, according to new data.

In new findings from a phase 2 trial from Soterios Pharma, STS-01 reached its primary efficacy endpoint in SALT 30 improvement versus placebo while also achieving significant total hair regrowth and being associated with no major adverse events. The findings—not yet published in a peer-reviewed publication—would support the progression of the investigative therapy into late-stage clinical trials.

The non-steroidal topical cream STS-01 1% is a cytokine-targeting agent that the UK-based Soterios highlighted as being “modified to maximize the efficacy of this mechanism, and offer a cosmetically elegant topical cream.”

“Whilst the JAK inhibitors have the potential to offer a new treatment option for severe patients, their use more broadly will be limited by concerns with their side effect profiles (and price),” the company stated.

The company conducted a randomized, placebo-controlled, multi-dose phase 2 trial assessing STS-01 in the treatment of patients with mild to moderate alopecia areata over 24 weeks. The trial population included 158 participants randomized to either daily STS-01 doses of 0.25%, 1% or 2%, or placebo. Treatment efficacy was assessed primarily as improvement in SALT score.

Approximately three-fourths (75.9%) of patients receiving once-daily STS 1% achieved the primary efficacy point of SALT 30 by 24 weeks, versus 36.7% of patients receiving placebo, according to Soterios (P <.0096). Additionally, 19% and 27% of patients receiving once-daily STS-01 1% and 2%, respectively, achieved total hair regrowth per SALT 0, versus only 3% of patients receiving placebo.

Regarding safety and tolerability, STS-01 was not associated with any major adverse events.

According to Soterios, STS-01 may now have the potential to be the first regulated therapy indicated to treat patients with mild to moderate alopecia areata per SALT <50 scores; this would represent more than 400,000 patients in the US alone.

"These results are extremely encouraging,” Arash Mostaghimi, MD, MPH, associate professor of dermatology at Brigham & Women's Hospital, said in a statement. “They validate the potential for STS-01 to provide mild-to-moderate alopecia sufferers with a safe and effective treatment for this debilitating condition. I am also excited by the prospect of targeting total hair regrowth in this patient group."

David Fleet, CEO of Soterios, stated the agent will move closer toward the company’s goal of US Food and Drug Administration application.

“This data gives us clarity and confidence in moving into late-stage clinical development for this product,” Fleet said in a statement. “We thank all the patients, investigators and healthcare staff who participated in this study."


  1. PRNewswire. Soterios Pharma Announces Positive Topline Results from Phase II Study of STS-01 in the Treatment of Mild / Moderate Alopecia Areata. Press release. Published May 30, 2024.
  2. Soterios. STS-01. Web page. Accessed May 30, 2024.