Akeso's AK157D1 (B7-H3 ADC) Cleared for Phase I Trial in Solid Tumors, Adding a Third Differentiated ADC to Its Pipeline

HONG KONG, Aug. 21, 2026 /PRNewswire/ -- Akeso, Inc. (9926.HK) ("Akeso" or the "Company") today announced that its investigational next-generation B7-H3-targeting antibody-drug conjugate (ADC), AK157D1, has received clinical trial clearance from the Center for Drug Evaluation (CDE) of China's National Medical Products Administration (NMPA). The clearance allows initiation of a Phase I study in patients with advanced malignant solid tumors. Development of AK157D1 in combination with Akeso's proprietary bispecific antibodies ivonescimab and cadonilimab is also planned.

AK157D1 is the third next-generation ADC candidate from Akeso to enter clinical development, following AK146D1 (TROP2/Nectin-4 ADC) and AK138D1 (HER3 ADC). The clearance further advances the Company's IO2.0 + ADC2.0 strategy and expands its broad innovative oncology pipeline.

B7-H3 is highly expressed in a broad range of solid tumors, including non-small cell lung cancer, small cell lung cancer, prostate cancer, esophageal cancer, nasopharyngeal carcinoma, colorectal cancer, breast cancer, and glioblastoma, with limited expression in normal tissues. This profile supports its potential as a broad-spectrum antitumor target.

AK157D1 was developed entirely in-house and incorporates a proprietary design. In preclinical studies, it has shown potent antitumor activity together with a favorable safety profile. These attributes may help address certain limitations associated with existing ADCs, including hematologic toxicity and interstitial lung disease, and support its continued development as a potential ADC of choice in both mono or combination therapies.

Akeso is advancing its IO2.0 + ADC2.0 strategy, built on proprietary bispecific and multispecific antibody technology and centered on cornerstone IO2.0 assets including ivonescimab and cadonilimab. Through this approach, the company is elevating treatment standards for major cancers worldwide and building a broad oncology portfolio to create next-generation standard of care.

In the immuno-oncology field, Akeso has two approved bispecific antibodies for cancer treatment. The Company is actively evaluating ivonescimab and cadonilimab in combination with its proprietary next-generation ADC candidates. Increasingly, global partners recognize both ivonescimab and cadonilimab as preferred agents for combination regimens and breakthrough therapy explorations across a wide spectrum of tumor types. In the ADC space, Akeso has built a differentiated pipeline of next-generation candidates, including AK146D1 and AK138D1, which are already in clinical development, and AK157D1 and AK158D1 (a bispecific ADC), which are anticipated to enter the clinic shortly. These agents are designed to address the narrow therapeutic window and safety limitations commonly associated with first-generation ADCs.

About AK157D1

AK157D1 is a novel B7-H3-targeting ADC independently developed by Akeso. It comprises a recombinant humanized IgG1/κ monoclonal antibody site-specifically conjugated to Dxd, a camptothecin-derived topoisomerase I inhibitor, via a maleimidocaproyl-alanine-alanine-alanine (MC-AAA) linker to interchain cysteine residues. Preclinical studies have demonstrated potent antitumor activity and a favorable safety profile.

About Akeso

Akeso (HKEX: 9926.HK) is a leading biopharmaceutical company committed to the research, development, manufacturing and commercialization of the world's first or best-in-class innovative biological medicines. Founded in 2012, Akeso has built a comprehensive R&D innovation ecosystem anchored by its proprietary Tetrabody antibody technology platform, AI-powered drug R&D platform, Dual-Shield ADC technology platform, Dual-Lock T-cell engager (TCE) technology platform, Tissue-Smart siRNA/mRNA technology platform, and cell therapy technology platforms.

Backed by world-class GMP manufacturing facilities and a highly efficient, integrated commercialization system, Akeso has developed into a globally competitive biopharmaceutical enterprise. Leveraging its fully integrated, multi-functional platform, the company maintains a robust pipeline of more than 50 innovative assets targeting cancer, autoimmune diseases, inflammation, metabolic disorders, and other major therapeutic areas. Of these, 27 candidates have advanced into clinical trials—including 15 bispecific or multispecific antibodies and bispecific ADCs—and 8 innovative drugs have reached commercial stage.

Through efficient and groundbreaking R&D, Akeso integrates premier global resources to develop transformative medicines, deliver high-quality, affordable therapeutic antibodies to patients worldwide, and generate sustained commercial and societal value as it strives to become a global leader in biopharmaceutical innovation.

Forward-Looking Statements

This announcement by Akeso, Inc. (9926.HK, "Akeso") contains "forward-looking statements". These statements reflect the current beliefs and expectations of Akeso's management and are subject to significant risks and uncertainties. These statements are not intended to form the basis of any investment decision or any decision to purchase securities of Akeso. There can be no assurance that the drug candidate(s) indicated in this announcement or Akeso's other pipeline candidates will obtain the required regulatory approvals or achieve commercial success. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the P.R. China, the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; Akeso's ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the Akeso's patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

Akeso does not undertake any obligation to publicly revise these forward-looking statements to reflect events or circumstances after the date hereof, except as required by law.

SOURCE Akeso, Inc.