A Phase I study of concurrent RMP-7 and carboplatin with radiation therapy for children with newly diagnosed brainstem gliomas

Abstract

Background: Ninety percent of children with diffuse, intrinsic brainstem tumors will die within 18 months of diagnosis. Radiotherapy is of transient benefit to these children, and a potential way to improve its efficacy is to add radiosensitizers. Carboplatin is antineoplastic and radiosensitizing; however, its delivery to the primary tumor site is problematic. RMP-7 is a bradykinin analog that causes selective permeability of the blood-brain-tumor interface. The objective of this Phase I study was to determine the toxicity and feasibility of delivering RMP-7 and carboplatin for 5 successive days during radiotherapy to children with newly diagnosed, diffuse, intrinsic brainstem gliomas.

Methods: RMP-7 was given prior to the end of carboplatin infusion. Local radiotherapy, in dose fractions of 180 centigrays (cGy) per day (to a total dose of 5940 cGy), was given within 4 hours of completion of drug delivery. Duration of treatment was escalated in a stepwise, weekly fashion in cohorts of 3 patients, until there was treatment-limiting toxicity or until radiotherapy was completed. Thirteen patients were treated, and their median age was 7 years (age range, 3-12 yrs).

Results: One child died early during treatment of progressive disease and was not assessable for toxicity. Treatment for 3 weeks, 4 weeks, and 5 weeks was tolerated well, with mild flushing, tachycardia, nausea, emesis, dizziness, and abdominal pain. One of 3 children treated at the full duration of therapy (33 doses over 7 weeks) developed dose-limiting hepatotoxicity and neutropenia. The estimated median survival was 328 days, and 1 patient remained free of disease progression for > 400 days after the initiation of treatment.

Conclusions: The results of this study confirmed the feasibility of giving RMP-7 and carboplatin daily during radiotherapy to children with brainstem tumors.