The CTLA-4 inhibitor ADG126, when combined with pembrolizumab, can be administered at a dose of 20 mg/kg every six weeks with fewer than 20% of patients experiencing Grade 3 adverse events.

ADG126, in conjunction with pembrolizumab, demonstrated a confirmed overall response rate (ORR) of 29% in patients with microsatellite stable colorectal cancer.

All six patients who responded to the 20 mg/kg dosage continue to receive treatment, with four having been in the study for over 40 weeks.

The median overall survival (OS) for the 10 mg/kg cohorts was 19.4 months, with a median follow-up of 17.8 months. Only one patient out of 41 was censored due to early withdrawal within the first 12 months.

SAN DIEGO and SUZHOU, China, May 22, 2025 — Adagene Inc. (Nasdaq: ADAG), a company focused on transforming the discovery and development of innovative antibody-based therapies, today released updated data from its Phase 1b/2 study on ADG126 in advanced microsatellite stable colorectal cancer (MSS CRC) without liver metastases, presented at ASCO.

Dr. Marwan Fakih, Professor of Medical Oncology and Therapeutics Research at City of Hope, stated, “The 20 mg/kg Q6W dosage has shown a notable decrease in treatment-related toxicities—with less than 20% Grade 3 adverse events and no discontinuations—while maintaining an ORR of nearly 30%, even in patients with peritoneal involvement. Importantly, responders in the 20 mg/kg cohorts are still on treatment, as confirmed by tumor assessments, CEA levels, and ctDNA biomarkers.” Dr. Fakih added, “The higher ORR and lasting responses are encouraging. Early separation is also evident on the Kaplan-Meier overall survival curves compared to historical controls. These findings align with the more mature overall survival observed in the 10 mg/kg cohorts.”

“CTLA-4 has been under investigation for over a decade, but toxicity remains the main obstacle to maximizing efficacy,” said Peter Luo, Ph.D., CEO and President of R&D at Adagene. “We are pleased with our predictive PK/PD framework, which integrates molecular design features and mechanism of action with clinical and preclinical tumor/plasma PK data for cross-reactive ADG126 in combination with anti-PD-1 therapy. This framework guides dosing regimens for MSS CRC patients without liver metastases, optimizing ADG126’s therapeutic index to maximize efficacy while minimizing cumulative treatment-related toxicities for long-term clinical benefit. Our masking technology further reduces toxicity, allowing patients to remain on treatment longer for sustained benefit.”

As of April 22, 2025, a total of 67 MSS CRC patients with no liver metastases, including those with peritoneal involvement, were treated with ADG126 at either 10 mg/kg or 20 mg/kg, combined with KEYTRUDA^® (pembrolizumab: 200 mg, Q3W), Merck & Co., Inc.’s anti-PD-1 therapy. The 10 mg/kg dose was given either every three weeks or every six weeks. The 20 mg/kg dose was administered as a single loading dose, followed by 10 mg/kg every three weeks, or 20 mg/kg every six weeks.

In the study’s dose expansion phase, the 10 mg/kg Q3W cohort showed an ORR of 17%, while the 20 mg/kg cohorts showed a confirmed ORR of 29%. The median duration of response (DoR) in the 10 mg/kg cohorts was 6.2 months, but the median DoR was not yet reached in the 20 mg/kg cohorts, and all responses are ongoing. The median overall survival (OS) for the 10 mg/kg cohorts was 19.4 months, comparing favorably with current standard of care treatments and historical benchmarks. The median OS for the 20 mg/kg cohorts has not yet been reached.

Both 20 mg/kg cohorts achieved equivalent ORRs of 29%, but adverse events were less severe and less frequent with Q6W dosing compared to a 20mg/kg loading dose followed by 10mg/kg Q3W.

As the data in the 20 mg/kg cohorts continues to mature, the Company plans to discuss the dosing regimen with regulatory bodies to secure their endorsement for the next phase of clinical development.

ASCO Poster Details

• Abstract Title: Safety and Efficacy of ADG126 (an Anti-CTLA-4 Masking Antibody) in Combination with Pembrolizumab: Updated Results of Phase 1b/2 Study in Advanced MSS CRC
• Date: Saturday, May 31, 2025
• Poster Viewing: 9:00 AM-12:00 PM CDT
• Onsite Location: McCormick Place, Chicago, IL, Board #248
• Abstract Number: 3579

The poster will be available on the company’s website Publications page.

About Adagene

Adagene Inc. (Nasdaq: ADAG) is a platform-driven, clinical-stage biotechnology company focused on transforming the discovery and development of innovative antibody-based cancer immunotherapies. Adagene utilizes computational biology and artificial intelligence to design novel antibodies that address unmet patient needs worldwide. The company has established strategic collaborations with reputable global partners to leverage its SAFEbody precision masking technology across multiple cutting-edge scientific approaches.

Powered by its proprietary Dynamic Precision Library (DPL) platform, consisting of NEObody™, SAFEbody, and POWERbody™ technologies, Adagene’s pipeline features highly differentiated immunotherapy programs. The company’s SAFEbody technology is designed to improve the safety and tolerability of many antibody therapeutics by using precision masking technology to shield the binding domain of the biologic therapy. Activation in the tumor microenvironment allows for tumor-specific targeting of antibodies, reducing on-target off-tumor toxicity in healthy tissues.

Adagene’s lead clinical program, ADG126 (muzastotug), is a masked, anti-CTLA-4 SAFEbody targeting a unique epitope of CTLA-4 in regulatory T cells (Tregs) within the tumor microenvironment. ADG126 is currently undergoing phase 1b/2 clinical studies in combination with anti-PD-1 therapy, with a particular focus on Metastatic Microsatellite-stable (MSS) Colorectal Cancer (CRC). Validated by ongoing clinical research, the SAFEbody platform can be applied to various antibody-based therapeutic modalities, including Fc empowered antibodies, antibody-drug conjugates, and bi/multispecific T-cell engagers.

For more information, please visit .
Follow Adagene on ,  and .

SAFEbody^® is a registered trademark in the United States, China, Australia, Japan, Singapore, and the European Union.

KEYTRUDA^® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc.

Investor Contacts:

Raymond Tam

Bruce Mackle
LifeSci Advisors