[Edaily Reporter KIM SAE-MI ] AprilBio Co.,Ltd.(397030)The atopic dermatitis treatment “EVO301” (APB-R3), which Safa (SAFA) licensed to U.S.-based Evomune, has reaffirmed its efficacy in a Phase 2a clinical trial and is moving on to subsequent clinical trials. This is seen as a turning point for the “SAFA” platform, which had been shaken by the suspension of development for “APB-A1”—a treatment for thyroid-associated ophthalmopathy (TED)—after its technology was licensed to Lundbeck.

EvoMune Releases Detailed Data on APB-R3… Reaffirms Efficacy in Phase 2a Clinical Trial

On the 1st (local time), Evomune presented additional results from the Phase 2a clinical trial of EVO301 for moderate-to-severe atopic dermatitis during a Late-Breaking Oral presentation at the European Academy of Dermatology and Venereology (EADV 2026) in Vienna, Austria.

EVO301 is a long-acting candidate drug created by fusing human-derived interleukin-18-binding protein (IL-18BP) to AprilBio Co.,Ltd.’s SAFA platform. In June 2024, AprilBio Co.,Ltd. licensed the global rights to APB-R3 to Evomune in a technology export deal valued at a total of $475 million (approximately 655.8 billion won).

This clinical trial enrolled 70 adult patients, divided into an EVO301 group (48 patients) and a placebo group (22 patients). Patients received two intravenous (IV) injections of 5 mg/kg—one on the study start date and another at week 4—and were monitored for efficacy and safety through week 12.

In previously released topline results, the primary endpoint—the mean improvement rate on the EASI scale at week 12—was 55% in the EVO301 group and 22% in the placebo group. The placebo-adjusted effect was 33 percentage points, and statistical significance (p<0.01) was achieved compared to placebo at weeks 4, 8, and 12.

At this EADV conference, patient-level response rates were also disclosed. The 12-week EASI-50 achievement rate was 63% in the EVO301 group and 23% in the placebo group, while the EASI-75 rates were 29% and 9%, respectively. The 12-week vIGA-AD 0/1 achievement rate, previously disclosed in the top-line results, was 22.9% in the EVO301 group and 0% in the placebo group.

Two Doses, 12-Week Duration of Effect… Efficacy Increased with Repeated Dosing in Phase 2b Clinical Trial

Particularly noteworthy are the number of doses and the duration of effect. Although EVO301 was administered only twice—at Week 0 and Week 4—the EASI improvement rate increased over time, reaching 41% at Week 4, 50% at Week 8, and 55% at Week 12. This indicates that not only did the clinical effect persist until 8 weeks after the final dose, but the degree of improvement also continued to increase.

This aligns with the design intent of SAFA, which binds to albumin to prolong the half-life in the body. Evomune analyzed that EVO301’s pharmacokinetic (PK) data supports once-monthly (Q4W) dosing and indicated the potential for dosing at 8- to 12-week intervals during future maintenance therapy. This can be viewed as evidence supporting the long-term sustainability of SAFA.

Mark G. Lebwohl, Professor of Dermatology at the Icahn School of Medicine at Mount Sinai in the U.S., commented, “With just two doses, the primary endpoint was met at weeks 4, 8, and 12, demonstrating a rapid and sustained response,” adding, “These results support the potential for EVO301 to become a first-line biologic treatment for atopic dermatitis in the future.”

Signs supporting the mechanism of action were also observed in biomarkers. CCL-17 (TARC) and CCL-22, which are Th2-related markers, decreased, with a reduction of approximately 75% observed in patients with high baseline TARC levels. Th1, Th17, and Th22-related markers, as well as IL-22—which is involved in skin barrier function—also decreased.

These results lend credence to Evomune’s hypothesis that blocking the upstream inflammatory signal IL-18 can influence not only Th2 but also various other inflammatory pathways. Professor Revol explained, “These data demonstrate that influencing not only Th2 but also other inflammatory pathways can significantly reduce disease activity in atopic dermatitis,” adding, “We have confirmed clinically meaningful therapeutic activity by targeting a new mechanism: IL-18.”

Safety was also favorable. The incidence of treatment-related adverse events was 10.4% in the EVO301 group and 13.6% in the placebo group. There were no treatment-related severe or serious adverse events, nor were there any treatment discontinuations due to adverse events. Conjunctivitis, which is a major adverse event associated with some biologics for atopic dermatitis, was not observed.

This Phase 2a trial served as a proof-of-concept (PoC) study to identify the optimal dose and dosing regimen, involving only two doses of EVO301 followed by an evaluation at 12 weeks. This differs from the trial design of existing atopic dermatitis treatments, where late-stage clinical trials typically involve repeated dosing and evaluate efficacy around 16 weeks. Evomune plans to fully optimize the dosage and dosing interval in subsequent clinical trials.

Luis Peña, CEO of Evomune, stated, “These data provide the basis for advancing EVO301 into a Phase 2b dose-finding trial,” adding, “Our goal in the Phase 2b trial is to optimize the dosage to further enhance treatment efficacy for patients.”

AprilBio Co.,Ltd. Overcomes Setback with ‘APB-A1’ and Reevaluates SAFA

From AprilBio Co.,Ltd.’s perspective, the significance of these results is even greater.

Previously, in August, another partner company, Lundbeck, halted further development for the APB-A1 TED clinical trial, noting that while biological activity was confirmed, the results fell short of expected clinical efficacy. Consequently, with the development of the first indication for a key SAFA pipeline halted, the importance of other cases demonstrating the platform’s clinical competitiveness had grown.

In this context, APB-R3 is significant because it is another new drug candidate utilizing SAFA that has demonstrated efficacy in a clinical trial involving actual patients. It is positive that the company has accumulated clinical references in humans that can be leveraged in future technology transfer processes for other SAFA pipelines.

Subsequent development is also proceeding as scheduled. Evomune announced plans to begin a Phase 2b clinical trial of the subcutaneous (SC) formulation in approximately 180 patients in the middle of next year. Over 16 weeks, the trial will compare three dosing regimens and explore dosing intervals of every 2 weeks (Q2W) and every 4 weeks (Q4W). The primary endpoint is the change in EASI at Week 16, while key secondary endpoints include EASI-50, 75, and 90; vIGA; Pruritus-NRS; and BSA.

Whether additional milestones will be triggered based on the company’s progress toward the Phase 2b trial and further development is also a point of interest. AprilBio Co.,Ltd. received an upfront payment of $15 million (approximately 20.7 billion won) for the APB-R3 technology transfer and subsequently received an additional $2 million (2.9 billion won) in development milestones based on clinical progress. Under the agreement, development milestones total up to $82.5 million (113.9 billion won), and commercialization milestones total up to $377.5 million (521.2 billion won).

This Phase 2a clinical trial reaffirmed the potential of the SAFA platform following the suspension of APB-A1’s development for TED. Efficacy was confirmed compared to a placebo after just two doses, and the effect persisted even after the final dose. Pharmacokinetic (PK) and biomarker results also supported long-term persistence and the mechanism of action. The extent to which efficacy can be enhanced in the upcoming Phase 2b clinical trial is expected to serve as a benchmark for assessing the value of APB-R3 and the SAFA platform.

AprilBio Co.,Ltd. official stated “The results from this Phase 2a clinical trial were obtained after administering APB-R3 just twice and observing patients for up to 12 weeks, which differs from existing atopic dermatitis treatments that require eight doses and evaluate efficacy around 16 weeks,” adding, “Since Phase 2b will involve greater drug exposure and repeated dosing, we expect to see improved efficacy compared to Phase 2a.”