[Kim Saemi, Edaily Reporter] South Korean biotech stocks came under pressure on Oct. 2, with AprilBio Co., Ltd. plunging 20% despite the release of additional Phase 2a data for its atopic dermatitis candidate, APB-R3. Peptron Inc. also fell sharply as the company repeatedly tempered expectations for a follow-on deal with Eli Lilly ahead of Oct. 7, a key date tied to their research collaboration.

AprilBio Plunges 20% as EVO301 Data Fall Short of Market Expectations

According to KG Zeroin’s MP DOCTOR, AprilBio closed at 17,020 won, down 20.09%, despite additional clinical data supporting the efficacy of APB-R3, which is licensed to U.S.-based Evommune Inc.

On October 1, Evommune unveiled detailed Phase 2a results for EVO301, formerly known as APB-R3. The candidate was administered only twice, at weeks 0 and 4, but achieved a mean 55% improvement in the Eczema Area and Severity Index (EASI) at week 12, compared to 22% for the placebo. The treatment effect continued to increase over the eight weeks following the final dose, with no treatment-related severe or serious adverse events reported.

Evommune stated that the results established proof of concept and that it plans to advance EVO301 into a Phase 2b study involving repeated subcutaneous dosing and dose optimization in mid-2027. For AprilBio, the results also demonstrated clinical efficacy for another candidate based on its SAFA platform, following the discontinuation of APB-A1 for thyroid eye disease.

Investors, however, appeared less impressed. Evommune shares plunged 12.71% to $8.26, giving the company a market capitalization of about $262 million, or 353.7 billion won. AprilBio likewise sank 20.09%, reducing its market capitalization to 469.1 billion won.

Attention focused on EVO301’s EASI-75 response rate of 29%, compared to 9% for the placebo. AprilBio argued that the result should be viewed in light of the limited two-dose regimen and highlighted a placebo-adjusted mean EASI improvement of 33 percentage points, similar to figures reported in Dupixent trials.

By comparison, Dupixent achieved EASI-75 rates of 51% and 44% in its SOLO 1 and SOLO 2 trials, compared to 15% and 12% for the placebo. Direct comparisons are limited, however, as EVO301 was evaluated with two doses over 12 weeks in Phase 2a, while Dupixent involved repeated dosing over 16 weeks in Phase 3.

AprilBio stated that the sell-off appeared excessive, arguing that investors viewed the data as failing to demonstrate clear superiority over competing therapies rather than as a clinical failure. The company expects that an optimized dosing regimen in Phase 2b could potentially improve efficacy.

Peptron Tempered Expectations for Lilly Deal Ahead of Oct. 7

Peptron closed at 129,500 won, down 9.12%, reversing much of the previous day’s rebound as investors weighed uncertainty surrounding its collaboration with Eli Lilly.

The two companies signed a technology evaluation agreement on Oct. 7, 2024, to assess Peptron’s SmartDepot long-acting drug-delivery technology in combination with Lilly’s peptide compounds. With the evaluation period described as lasting “up to 24 months,” investors have viewed Oct. 7, 2026, as a potential milestone for a follow-on commercial agreement.

Peptron, however, has repeatedly sought to temper those expectations. On Sept. 12, the company stated that Oct. 7 refers to the basic term of the research agreement and is not a deadline for signing a commercial deal.

The company then issued shareholder FAQs on September 30 and October 1, reiterating that the collaboration with Lilly remains ongoing while emphasizing that the 24-month period is merely the maximum evaluation period.

Peptron also clarified that several developments are unrelated to Lilly. It stated that PT403 and PT404 are independently developed SmartDepot pipeline candidates, while a recently granted Korean patent for a long-acting GLP-1 formulation was filed solely by Peptron and is not a new result of the Lilly collaboration.

The company also emphasized that its second Osong plant is not being built based on the assumption of a licensing agreement or commercial manufacturing volumes from any specific global pharmaceutical company.

“It raises questions as to why the company is repeating previous explanations at this particular point while distancing various developments from Lilly,” said a biotech industry official. “If the lengthy evaluation ultimately fails to lead to a commercial agreement, Peptron could end up having committed significant time without securing an upfront payment.”