A Multicenter Phase II Trial of Nimustine Hydrochloride Administered via Convection‐Enhanced Delivery in Children With DIPG

Diffuse intrinsic pontine glioma (DIPG) is a very challenging-to-treat pediatric malignant tumor, with a median survival time of < 12 months. Convection-enhanced delivery (CED) allows for direct drug administration into the tumor site, showing potential as a novel therapeutic approach. This study evaluated the efficacy of CED of nimustine hydrochloride (ACNU) in children with DIPG. This phase 2, single-arm, multicenter study enrolled patients aged 3-21 years and diagnosed with DIPG. The investigational treatment commenced 1 month after completing radiotherapy (local 50-60 Gy). The treatment involved stereotactic brain surgery for catheter placement, followed by ACNU administration via a CED catheter at a concentration of 0.75 mg/mL for 2-3 days until a cumulative dose of 7 (±0.3) mL was achieved. The primary endpoint was the 1-year survival rate. From April 2018 to March 2020, 21 children were enrolled in the trial and treated, with 20 evaluable for the primary endpoint. The 1-year survival rate from the start of radiotherapy was 60%, and the median survival time was 15 months. The response rate was analyzed in 20 patients, with one complete response (CR), six partial responses (PR), nine stable diseases, and four progressive diseases, resulting in a response rate of 35% (CR + PR). The CED of ACNU in the brainstem of children with DIPG after radiotherapy appears to be an effective therapeutic strategy. This approach warrants further development as a treatment for children with DIPG. This study is registered with jRCT (No. jRCT2021190003).