Phase I trial of convection-enhanced delivery of IL13-Pseudomonas toxin in children with diffuse intrinsic pontine glioma

Abstract

OBJECTIVE In this clinical trial report, the authors analyze safety and infusion distribution of IL13-Pseudomonas exotoxin, an antitumor chimeric molecule, administered via intratumoral convection enhanced delivery (CED) in pediatric patients with diffuse intrinsic pontine glioma (DIPG). METHODS This was a Phase I single-institution, open-label, dose-escalation, safety and tolerability study of IL13-PE38QQR infused via single-catheter CED into 5 pediatric DIPG patients. IL13-PE38QQR was administered to regions of tumor selected by radiographic findings. Two escalating dose levels were evaluated: 0.125 µg/mL in cohort 1 and 0.25 µg/mL in cohort 2. Real-time MRI was performed during intratumoral infusions, and MRI and MR spectroscopy were performed before and after the infusions. Clinical evaluations, including parent-reported quality of life (QOL), were assessed at baseline and 4 weeks post-infusion. RESULTS Direct infusion of brainstem tumor with IL13-PE using the CED technique in patients with DIPG produced temporary arrest of disease progression in 2 of 5 patients, both of whom subsequently received a second infusion. All 5 patients showed signs of disease progression by 12 weeks after initial infusion. Two patients experienced transient cranial nerve deficits and lethargy after infusion, and these deficits resolved with corticosteroid treatment in both cases. No patient had radiographic evidence of acute or long-term treatment toxicity. Parent-reported QOL was consistent with medical outcomes. CONCLUSIONS Even though IL13-PE delivered by CED did not reach the entire MRI-defined tumor volume in any patient, short-term radiographic antitumor effects were observed in 2 of the 5 patients treated. The patients’ performance status did not improve. Drug delivery using multiple catheters may produce improved outcomes. Clinical trial registration no.: NCT00088061 (clinicaltrials.gov) ABBREVIATIONS CED = convection-enhanced delivery; DIPG = diffuse intrinsic pontine glioma; IL-13 = interleukin 13; IL13R = IL-13 receptor; IPI = Impact of Pediatric Illness; KPS = Karnofsky Performance Status; LPS = Lansky Performance Status; MRS = MR spectroscopy; NAA = n-acetyl aspartate; QOL = quality of life; Vd = volume of distribution; Vi = volume of infusion.

Keywords: CED; CED = convection-enhanced delivery; DIPG; DIPG = diffuse intrinsic pontine glioma; Gd-DTPA; IL-13 = interleukin 13; IL13-PE; IL13R = IL-13 receptor; IPI = Impact of Pediatric Illness; KPS = Karnofsky Performance Status; LPS = Lansky Performance Status; MR-spectroscopy; MRS = MR spectroscopy; NAA = n-acetyl aspartate; QOL = quality of life; Vd = volume of distribution; Vi = volume of infusion; convection-enhanced delivery; oncology; pediatric brain tumors.

FIG. 1.

Second infusion in patient 5. Intraoperative coronal (A) and sagittal-oblique (B) T1-weighted MR images demonstrating retrograde flow of infusate back into the old cannula tract from the infusion 4 weeks prior.

FIG. 2.

Patient 3. Sagittal contrast-enhanced T1-weighted MR images obtained preoperatively (A) and 1 month (B) and 2 (C) and 3 (D) months postoperatively. The 1-month follow-up image (B) shows minimal enhancement, low perfusion, and necrosis at the infusion site consistent with treatment response.

FIG. 3.

Patient 5. Sagittal contrast-enhanced T1-weighted MR images obtained preoperatively (A) and 1 month (B) and 2 (C) and 3 (D) months postoperatively. The 1-month follow-up image (B) shows minimal enhancement, low perfusion, and necrosis at the infusion site consistent with treatment response.

FIG. 4.

Patient 5. MRS findings. A: Before initial infusion: NAA/creatine (Cr) ratio of 0.60, choline (Cho)/Cr ratio of 4.47, and Cho/NAA ratio of 7.44. B: One month postoperatively: NAA/Cr ratio of 10.4, Cho/Cr ratio of 38.3, and Cho/NAA ratio of 3.68. C: Three months postoperatively: NAA/Cr ratio of 0.31, Cho/Cr ratio of 2.76, and Cho/NAA ratio of 8.93.

FIG. 5.

Patient 2. Intraparenchymal air effects on infusate distribution. A–F: Serial axial T1-weighted MR images obtained every 50 minutes, demonstrating the impact of an intraparenchymal air bubble (hypointensity) introduced at the start of the infusion. While there was a small decrease in the volume of air over time, the serial images demonstrate the restriction of anteromedial spread of infusate (hyperintensity) by the air in the parenchyma.