Clinical Summary:

• Design/Population: In this phase 2 study, patients aged 5 to 15 years with newly diagnosed diffuse intrinsic pontine glioma received ACT001 plus standard radiotherapy followed by maintenance ACT001. 
• Key Outcomes: The regimen demonstrated encouraging antitumor activity, with partial responses, disease control in most patients, and median overall survival of approximately 1 year. 
• Clinical Relevance: These findings suggest that ACT001 plus radiotherapy may offer a promising new treatment approach for pediatric patients with diffuse intrinsic pontine glioma, a disease with limited effective options. 

Results from a phase 2 trial demonstrated that ACT001 combined with standard radiotherapy showed encouraging clinical promise among newly diagnosed pediatric patients with diffuse intrinsic pontine glioma. 

These results were presented by Jing Zhang, MD, Beijing Tiantan Hospital, Beijing, China, at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

In this open-label, multicenter study, 33 newly diagnosed patients aged 5 to 15 years with diffuse intrinsic pontine glioma received 54 Gy in 30 fractions of radiotherapy plus 700 mg/m² of ACT001 twice daily during a 6-week concurrent phase, followed by ACT001 maintenance until disease progression or unacceptable toxicity. Primary end points included objective response rate (ORR) and overall survival (OS). Key secondary end points included progression-free survival (PFS), 1-year OS rate, and safety. 

In the full analysis set, the ORR was 30.3%, with 10 patients achieving a partial response. The disease control rate was 75.8% and 21.2% of patients in the per-protocol population experienced >50% reduction in pontine tumor volume. Median OS was 12.7 months with a 1-year OS rate of 50.1%. Median PFS was 5.9 months with a 6-month PFS rate of 45.3%. 

Multivariate analysis identified higher baseline Lansky performance scores as a favorable predictor of OS (hazard ratio [HR] = 0.899; P = .0069), while achieving a partial response was associated with improved PFS (HR = 0.232; P = .0162). Among 19 patients who received salvage therapy after disease progression, those treated with reirradiation achieved a median OS of 17.9 months, significantly longer than that observed among patients who did not undergo reirradiation (P = .031).

Treatment-related adverse events were reported in 96.9% of patients and were predominantly grade 1/2. Grade ≥3 adverse events were reported in 18.2% of patients, and most frequently included lymphopenia, weight loss, and upper respiratory tract infection. No treatment-related deaths were reported and no patients discontinued ACT001 due to toxicity. Additionally, 96.9% of patients experienced stable or improved Lansky performance scores following treatment.

 “This regimen provides a new treatment option for pediatric [diffuse intrinsic pontine glioma] and warrants further verification in larger-scale randomized controlled trials,” concluded Dr Zhang. 

Source:

Zhang J, Qiu X, Liu Y, et al. Phase II clinical study of ACT001 combined with radiotherapy in newly diagnosed pediatric diffuse intrinsic pontine glioma. Presented at the ASCO Annual Meeting. May 29 - June 2, 2026. Chicago, Illinois. Abstract 439.