I-131 radioconjugated antibodies for the locoregional radioimmunotherapy of high-grade malignant glioma - Phase I and II study

Locoregional radioimmunotherapy (LR-RIT) was administered to 111 patients ( 20 were recruited in a phase I and 91 in a phase II study) with malignant g liomas: I patient with oligodendroglioma, 7 patients with anaplastic oligod endroglioma, 2 with grade II astrocytoma, 10 with anaplastic astrocytoma an d 91 with glioblastoma, amounting to 58 newly diagnosed and 53 recurrent tu mours. The I-131-labelled monoclonal antibodies BC-2 and BC-4 were used in order to recognize stromal and intracellular glycoprotein tenascin, an anti gen present particularly in glioblastoma. The patients were enrolled betwee n February 1990 and December 1997 after conventional therapy. The radiophar maceutical was injected directly into the tumour site. Sequential scintigra phies demonstrated a high and enduring uptake in the tumour. The mean irrad iation dose in the tumour was 300 Gy per cycle. In the group of 74 phase II glioblastoma patients the clinical responses were as follows: 10 patients with stable disease (SD), 9 with partial responses (PR), 23 with no evidenc e of disease (NED) and 10 patient with complete response (CR). The median s urvival was 19 months. The response rate (CR + PR + NED) was 17.8% for thos e patients with bulky lesions, with a median survival of 17 months, but 66. 6% for patients with small lesions, with a median survival of 25 months. Be tter outcomes were recorded in cases with less aggressive diseases: oligode ndroglioma, anaplastic oligodendroglioma and anaplastic astrocytoma. We con clude that fractionated LR-RIT can be safely performed, with promising resu lts especially in patients with minimal disease.