Ascentage Pharma Achieves First Clinical Dataset for Alrizomadlin in Pediatric Solid Tumors at ASCO 2026

Preliminary clinical data for alrizomadlin (APG-115), Ascentage Pharma's MDM2-p53 inhibitor, signal early antitumor activity in a patient population where treatment options remain critically limited, a finding with direct implications for oncology pipeline teams tracking apoptosis-pathway agents in pediatric indications.

Presented in a rapid oral session at the 62nd ASCO Annual Meeting, the dataset covers alrizomadlin as monotherapy and in combination with investigational Bcl-2 inhibitor lisaftoclax (APG-2575) in pediatric patients with relapsed or metastatic rhabdomyosarcoma and other soft-tissue sarcomas. Monotherapy produced one complete response in a pediatric RMS patient. The combination arm, evaluated across 17 response-evaluable patients, returned an objective response rate of 23.5%, including one complete response in Ewing sarcoma and three partial responses. Both regimens demonstrated a manageable safety profile.

For regulatory affairs leads monitoring accelerated development pathways in emerging markets, the NMPA designation is the more consequential data point. China's Center for Drug Evaluation (CDE) has formally included alrizomadlin in the Pilot Program for the Support of Anti-tumor Drugs R&D for Kids, the SPARK Plan, covering neuroblastoma, rhabdomyosarcoma, and Ewing sarcoma. The SPARK Plan functions as an accelerated development designation for pediatric oncology agents, and its application to alrizomadlin represents one of the earlier instances of the pathway being applied to a first-in-class mechanistic target. Companies pursuing similar designations in China should read the inclusion as a precedent for MDM2-p53 inhibitors meeting the program's evidentiary threshold.

Alrizomadlin is orally administered and works by blocking the MDM2-p53 protein-protein interaction, restoring p53 tumor suppressor activity and inducing apoptosis. Ascentage describes it as the first agent of its class to enter clinical development in China. The ASCO presentation marks the company's ninth consecutive appearance at the meeting; six studies across three pipeline assets were selected this year, with three receiving rapid oral slots.

Enrollment and response data from the combination cohort will serve as a measurable checkpoint for the program's advancement toward a registrational study design under the SPARK Plan framework.

Source: Ascentage Pharma via GlobeNewswire, May 31, 2026.