LOCAL TREATMENT OF MALIGNANT GLIOMAS BY DIRECT INFUSION OF SPECIFIC MONOCLONAL-ANTIBODIES LABELED WITH I-131 - COMPARISON OF THE RESULTS OBTAINED IN RECURRENT AND NEWLY-DIAGNOSED TUMORS

Two murine monoclonal antibodies, BC-2 and BC-4, raised against tenasc in and labeled with I-131 were infused locally in the site of neoplast ic disease by means of a removable (16 patients) or indwelling (34 pat ients) catheter. Fifty patients bearing a malignant glioma were treate d. Twenty-six of these were suffering from recurrent disease; their tu mors relapsed within 9 months (median) after treatment, The remaining 24 cases had a newly diagnosed tumor, and local radioimmunotherapy OUT ) was given immediately after surgery and radiochemotherapy. All effor ts were made to reduce the tumor before the infusion of the radiopharm aceutical, Therefore, 22 cases with relapsing glioma underwent additio nal debulking surgery, which led to total or subtotal removal of tumor in 9 of the patients. Altogether, 28 patients had intralesional RIT w hen the disease was minimal or microscopic, Conversely, 22 cases under went local RIT with a tumor the diameter of which was >2 cm, In many c ases, the infusions were repeated up to six times to achieve complete destruction of the neoplastic tissue. The local treatment did not give rise to systemic or to cerebral adverse effects, The labeled monoclon al antibodies, given directly in the site of the lesion, concentrated in very high amount in the neoplastic tissue and remained fixed in the target for a long period of time, For these reasons, the radiation do se to the tumor was remarkable (on average >30,000 cGy/cycle) and cons equently led to promising results. The median survival was, in total, 20 months (18 in recurrent tumors and 23 in newly diagnosed lesions), Moreover, median survival was 17 months in patients with bulky tumors (both recurrent and newly diagnosed tumors) and 26 months in patients with minimal or microscopic disease, The median time to progression wa s 3 months in recurrent and 7 months in newly diagnosed gliomas, Final ly, RIT produced 3 CRs (all in recurrent tumors), 6 PRs (4 in recurren t and 2 in newly diagnosed), and 11 stabilizations of disease (4 in re current and 7 in newly diagnosed), In 19 cases (13 recurrent and 6 new ly diagnosed) the progression of tumor was recorded. Eleven patients ( 2 recurrent and 9 newly diagnosed) who were treated by RIT when their disease was minimal and nondetectable by radiological methods remained disease-free and were classified as NED, The overall response rate (N ED plus CR plus PR) was 40% (34.6% recurrent and 45.8% newly diagnosed ), These data provide evidence for the capability of this new therapeu tic technique to achieve, in a significant number of cases, lasting co ntrol of malignant gliomas and suggest the opportunity to apply this t reatment in an adjuvant setting.