Regression of Recurrent Malignant Gliomas With Convection-Enhanced Delivery of Topotecan

BACKGROUND: Convection-enhanced delivery of chemotherapeutics for the treatment of malignant glioma is a technique that delivers drugs directly into a tumor and the surrounding interstitium through continuous, low-grade positive-pressure infusion. This allows high local concentrations of drug while overcoming the limitations imposed by toxicity and the blood-brain barrier in systemic therapies that prevent the use of many potentially effective drugs. OBJECTIVE: To examine the safety profile of a conventional chemotherapeutic agent, topotecan, via convection-enhanced delivery in the treatment of recurrent malignant gliomas and secondarily to assess radiographic response and survival. METHODS: We performed a prospective, dose-escalation phase Ib study of the top-oisomerase-I inhibitor topotecan given by convection-enhanced delivery in patients with recurrent malignant gliomas. RESULTS: Significant antitumor activity as described by radiographic changes and prolonged overall survival with minimal drug-associated toxicity was demonstrated. A maximum tolerated dose was established for future phase II studies. CONCLUSION: Topotecan by convection-enhanced delivery has significant antitumor activity at concentrations that are nontoxic to normal brain. The potential for use of this therapy as a generally effective treatment option for malignant gliomas will be tested in subsequent phase II and III trials.