Soquelitinib Phase 1 Data Show Sustained Clinical Improvement With Extended Treatment in AD

Extended treatment with Corvus Pharmaceuticals’ investigational oral ITK inhibitor soquelitinib resulted in deepening clinical responses and a favorable safety profile in patients with moderate to severe atopic dermatitis (AD), according to new data from cohort 4 of a randomized, blinded, placebo-controlled phase 1 trial. The findings build on earlier cohort results and support advancement into a phase 2 program.^1,2

Soquelitinib is a selective inhibitor of interleukin-2–inducible T-cell kinase (ITK), a signaling molecule involved in T-cell differentiation and cytokine production. By targeting ITK, soquelitinib is designed to modulate multiple inflammatory pathways implicated in AD, including Th2- and Th17-mediated signaling, while promoting immune rebalancing through regulatory T-cell (Treg) activity.

“ITK is interesting in that it has a very limited distribution in the body, so it's solely expressed in T, NK, and ILC2 cells. So when you selectively block it with soquelitinib, you can selectively inhibit TH2 and TH17 expression, which are very relevant in atopic dermatitis and other conditions, while sparing TH1, which is important in preserving immune function,” said Albert Chiou, MD, MBA, dermatologist, clinical associate professor of dermatology at the Stanford University School of Medicine in California, and a phase 1 investigator, in a previous interview.

Cohort 4 was prospectively designed to extend treatment duration to 56 days, compared with the 28-day treatment period used in cohorts 1 through 3. Patients were randomized 1:1 to receive soquelitinib 200 mg twice daily or placebo. Notably, cohort 4 included a higher proportion of patients with more advanced disease and prior systemic treatment exposure, reflecting a clinically challenging population.

Results

At day 56, patients treated with soquelitinib achieved a mean 72% reduction in Eczema Area and Severity Index (EASI) score, compared with a 40% reduction in the placebo group. Continuous improvement was observed from day 28 through day 56, with increasing separation between treatment arms over time. Two placebo-treated patients experienced disease flares requiring rescue therapy during the treatment period, whereas no flares were reported in the soquelitinib group.

“The results from cohort 4 increase our confidence that soquelitinib could become a leading oral therapy for the treatment of atopic dermatitis,” said Richard A. Miller, MD, co-founder, president, and chief executive officer of Corvus Pharmaceuticals, in the news release. “The results also support our hypothesis from cohort 3 that the longer treatment could achieve deepening of clinical responses.”

Clinically meaningful response thresholds further favored soquelitinib. At day 56, 75% of treated patients achieved EASI 75, 25% achieved EASI 90, and 33% achieved Investigator Global Assessment (IGA) scores of 0 or 1. Corresponding response rates in the placebo arm were 20% for EASI 75, with no patients achieving EASI 90 or IGA 0/1. Separation of response curves was evident as early as day 15 and remained statistically significant at day 56.

Importantly, efficacy was maintained across subgroups, including patients with prior systemic therapy exposure. Across cohorts 1 through 4, 35% of enrolled patients had received prior systemic treatments, most commonly dupilumab (Dupixent; Sanofi and Regeneron), as well as JAK inhibitors and corticosteroids. Response kinetics among soquelitinib-treated patients were similar regardless of prior treatment history, whereas placebo-treated patients with prior systemic exposure demonstrated less improvement. In cohort 4, 3 of 5 soquelitinib-treated patients with prior systemic therapy achieved EASI 75, compared with none in the placebo group.

Biomarker analyses provided mechanistic support for the observed clinical activity. Treatment with soquelitinib was associated with reductions in serum IL-4, IL-5, IL-17, and TARC levels, along with decreases in circulating Th2 cells. These effects were dose- and duration-dependent, with the most pronounced cytokine reductions observed in cohort 4. Increases in circulating Treg cells were also observed, particularly in patients receiving longer treatment, and were associated with sustained disease control during follow-up.

Soquelitinib was generally well tolerated. In cohort 4, adverse events were reported in 41.7% of soquelitinib-treated patients and 50% of placebo-treated patients; all events were grade 1 or 2. No serious adverse events, dose interruptions, or clinically significant laboratory abnormalities were reported.

Future Outlook

Based on these findings, Corvus Pharmaceuticals plans to initiate a phase 2 trial in the first quarter of 2026, enrolling approximately 200 patients with moderate to severe AD who have failed at least one prior topical or systemic therapy. The trial will evaluate multiple dosing regimens over a 12-week treatment period, with efficacy and durability of response as key end points.

“Bottom line, we believe this is a successful Phase 1 program and the results have become stronger the longer we treat, without compromising safety. We believe this bodes well for advancing soquelitinib to the next phase where we will further test soquelitinib in a larger patient population. Taken altogether, we believe the data indicate that soquelitinib has the potential to be an important new medicine for first line or later line therapy of patients with atopic dermatitis that could be among the most active approved or investigational drugs for this indication,” Miller said.

References

1. Corvus Pharmaceuticals announces positive data from cohort 4 confirming results for placebo-controlled phase 1 clinical trial of soquelitinib for atopic dermatitis. News release. Corvus Pharmaceuticals. January 20, 2026. Accessed January 20, 2025.
2. Corvus Pharmaceuticals announces data from cohorts 1-3 of placebo-controlled phase 1 clinical trial of soquelitinib for atopic dermatitis. Corvus Pharmaceuticals. News release. May 8, 2025. Accessed January 20, 2026. https://investor.corvuspharma.com/news-releases/news-release-details/corvus-pharmaceuticals-announces-data-cohorts-1-3-placebo