Phase I trial of convection-enhanced delivery of nimustine hydrochloride (ACNU) for brainstem recurrent glioma

Background: Treatment options for patients suffering brainstem gliomas are quite limited as surgery is not an option against intrinsic tumors at brainstem and chemotherapy generally failed to demonstrate its efficacy. Intracerebral convection-enhanced delivery (CED) is a novel approach for administering chemotherapy to patients with brain tumors. We present the results of phase I trial of CED of nimustine hydrochloride (ACNU), designed to determine the maximum tolerable concentration of ACNU, for patients with recurrent brainstem gliomas.

Methods: Sixteen patients, aged 3-81 years old, suffering from recurrent brainstem gliomas, including diffuse intrinsic pontine glioma patients as well as patients with recurrent gliomas that originated from non-brainstem sites, were enrolled in this trial between February 2011 and April 2016. The dose/concentration escalation trial included 3 dose/concentration groups (0.25, 0.5, and 0.75 mg/mL, all at 7 mL) to determine the safety and tolerability of CED of ACNU. Real-time monitoring of drug distribution was performed by mixing gadolinium-tetraazacyclododecanetetraacetic acid (Gd-DOTA) in the infusion solution. CED of ACNU was given in combination with oral or intravenous temozolomide chemotherapy.

Results: CED of ACNU demonstrated antitumor activity, as assessed by radiographic changes and prolonged overall survival. The recommended dosage was 0.75 mg/mL. Drug-associated toxicity was minimal.

Conclusions: Intracerebral CED of ACNU under real-time monitoring of drug distribution, in combination with systemic temozolomide, was well tolerated among patients with recurrent brainstem gliomas. The safety and efficacy observed suggest the clinical benefits of this strategy against this devastating disease. Based on this phase I study, further clinical development of ACNU is warranted.