Ascentage Pharma Presents Its First Dataset on MDM2-p53 Inhibitor Alrizomadlin (APG-115) in Pediatric Solid Tumors at ASCO 2026

On May 31, 2026 Ascentage Pharma Group International (NASDAQ: AAPG; HKEX: 6855), a global, commercial-stage, integrated biopharmaceutical company engaged in the discovery, development and commercialization of novel therapies to address unmet medical needs in cancer, reported that the Company presented its first dataset of alrizomadlin (APG-115), an MDM2-p53 inhibitor from the Company’s apoptosis-targeted pipeline, as monotherapy or in combination with lisaftoclax (APG-2575) in pediatric patients with relapsed/metastatic rhabdomyosarcoma (RMS) or other soft-tissue sarcomas (STSs), in a rapid oral presentation at the 62nd American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting.

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The ASCO (Free ASCO Whitepaper) Annual Meeting showcases cutting-edge research in clinical oncology and advanced cancer therapies and is the world’s largest gathering of the clinical oncology community. This year marks Ascentage Pharma’s ninth consecutive appearance at ASCO (Free ASCO Whitepaper). A total of six studies involving three of the Company’s key assets were selected for presentation, including three rapid oral presentations.

The data presented demonstrated preliminary antitumor activity and a manageable tolerability profile of alrizomadlin in pediatric solid tumors. Results showed that alrizomadlin monotherapy demonstrated initial clinical benefit in pediatric rhabdomyosarcoma (RMS), with one pediatric patient achieving a complete response (CR). In combination with investigational selective Bcl-2 inhibitor lisaftoclax, encouraging antitumor activity was observed, with an objective response rate (ORR) of 23.5% among 17 response-evaluable patients, including one complete response in a patient with Ewing sarcoma and three partial responses (PRs). In terms of safety, alrizomadlin, either as monotherapy or in combination with lisaftoclax, demonstrated a manageable safety profile in pediatric patients with solid tumors.

Alrizomadlin is an orally administered, highly selective MDM2-p53 inhibitor independently developed by Ascentage Pharma. It is the first investigational agent of its class to enter clinical development in China and has global first-in-class potential. By blocking the MDM2-p53 protein-protein interaction, alrizomadlin restores the tumor suppressor activity of p53 and induces apoptosis in tumor cells. Recently, alrizomadlin was officially included by the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) in the Pilot Program for the Support of Anti-tumor Drugs R&D for Kids, also known as the "SPARK Plan," for development in pediatric solid tumors including neuroblastoma, rhabdomyosarcoma, and Ewing sarcoma.

Professor Yizhuo Zhang, principal investigator of the study from the Department of Pediatric Oncology at Sun Yat-sen University Cancer Center, said: "Relapsed/refractory pediatric sarcomas are associated with extremely poor prognosis and substantial unmet medical needs. The data presented at the ASCO (Free ASCO Whitepaper) meeting demonstrated a favorable tolerability profile and promising anti-tumor effect for alrizomadlin both as monotherapy and in combination with lisaftoclax, with the complete response (CR) cases being particularly encouraging. As a key candidate included in the SPARK Plan, alrizomadlin has the potential to become a first-in-class therapy, address unmet medical needs, and bring new hope for long-term survival to pediatric patients."

Professor Yi Zhang, investigator of the study from the Department of Pediatrics at Beijing Tongren Hospital, Capital Medical University, said: "Treatment options for pediatric solid tumors, especially advanced soft-tissue sarcomas, remain very limited. The clinical data generated by the alrizomadlin combination regimen are therefore particularly meaningful. This apoptosis pathway-targeting therapy demonstrated favorable tolerability and encouraging objective response rates, further supporting the therapeutic potential of dual-target combination approaches in refractory pediatric tumors and providing valuable direction for future precision drug development in pediatric oncology."

Yifan Zhai, MD, Chief Medical Officer of Ascentage Pharma, said: "Pediatric solid tumors continue to represent an area of significant unmet medical need. The data presented at ASCO (Free ASCO Whitepaper) mark our first presentation of alrizomadlin clinical data in pediatric solid tumor patients and demonstrated encouraging preliminary clinical benefit and tolerability. Importantly, alrizomadlin has already been included by the CDE in the SPARK Plan for potential development in multiple pediatric solid tumors. The data presented provide initial clinical evidence supporting this development strategy. We will continue to advance the related clinical studies with the goal of bringing new treatment options to pediatric patients in urgent need."

Key highlights from the study presented at the 2026 ASCO (Free ASCO Whitepaper) Annual Meeting are as follows:

Alrizomadlin (APG-115) alone or in combination with Lisaftoclax (APG-2575) for the treatment of pediatric patients with relapsed/metastatic rhabdomyosarcoma (RMS) or other soft-tissue sarcomas (STSs)
Abstract #: 10012
Presentation Type: Rapid Oral Presentation
Session Title: Pediatric Oncology II
First Author: Yizhuo Zhang, MD, Department of Pediatric Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine
Key Highlights:

Research Background: This multicenter clinical trial conducted in China evaluated the safety and preliminary efficacy of alrizomadlin (APG-115) as monotherapy or in combination with lisaftoclax in heavily pretreated pediatric patients with relapsed/metastatic RMS, Ewing sarcoma (EWS), neuroblastoma (NB), and other solid tumors.
Efficacy Data: In the monotherapy arm, 1 patient with refractory RMS achieved CR. In the combination arm, among 17 response-evaluable pediatric patients with relapsed/refractory solid tumors, the ORR was 23.5%, including 1 CR in a patient with EWS, as well as PRs in 2 patients with RMS and 1 patient with NB. The disease control rate (DCR) was 70.6%.
Safety Data: No dose-limiting toxicities (DLTs) were observed in either the monotherapy or combination arm. Adverse events were primarily gastrointestinal and hematologic, with few serious adverse events and no treatment-related deaths or discontinuations.
Conclusion: The regimen demonstrated a manageable safety profile and preliminary antitumor activity in pediatric solid tumors, supporting further investigation.

* Alrizomadlin is currently under investigation and has not yet been approved by the US FDA.

(Press release, Ascentage Pharma, MAY 31, 2026, View Source [SID1234666283])