PNOC015: Repeated convection-enhanced delivery of MTX110 (aqueous panobinostat) in children with newly diagnosed diffuse intrinsic pontine glioma

Abstract Background The objective of this study was to determine the safety, tolerability, and distribution of MTX110 (aqueous panobinostat) delivered by convection-enhanced delivery (CED) in patients with newly diagnosed diffuse intrinsic pontine glioma (DIPG) who completed focal radiation therapy (RT). Methods Patients with DIPG (2–21 years) were enrolled after RT. CED of MTX110 combined with gadoteridol was completed across 7 dose levels (DL) (30–90 µM; volumes ranging from 3 mL to 2 consecutive doses of 6 mL). An accelerated dose escalation design was used. Distribution of infusate was monitored with real-time MR imaging. Repeat CED was performed every 4–8 weeks. Quality-of-life (QoL) assessments were obtained at baseline, every 3 months on therapy, and end of therapy. Results Between May 2018 and March 2020, 7 patients who received a total of 48 CED infusions, were enrolled (median age 8 years, range 5–21). Three patients experienced dose-limited toxicities. Four grade 3 treatment-related adverse events were observed. Most toxicities were transient new or worsening neurologic function. Median overall survival (OS) was 26.1 months (95% confidence interval: 14.8–not reached). Progression-free survival was 4–14 months (median, 7). Cumulative percentage of tumor coverage for combined CED infusions per patient ranged from 35.6% to 81.0%. Increased CED infusions were negatively associated with self-reported QoL assessments. Conclusion Repeat CED of MTX110 with real-time imaging with gadoteridol is tolerable for patients with DIPG. Median OS of 26.1 months compares favorably with historical data for children with DIPG. The results support further investigation of this strategy in a larger cohort.