Multicenter Phase I Trial of Intraventricular Immuno-Chemotherapy in Recurrent CNS Lymphoma

We recently studied the safety and activity of intraventricular rituximab monotherapy in the treatment of recurrent intraocular and CNS non-Hodgkin lymphoma (NHL) (JCO 2007 25: 1350–1356). Rapid dissemination throughout the craniospinal axis was demonstrated and cytologic responses were detected in six out of ten patients. Two patients experienced improvement in intraocular NHL and one exhibited resolution of parenchymal NHL. The major goals of this current trial are to perform the first study of intraventricular immuno-chemotherapy in humans and to evaluate the safety of two dose levels of intraventricular rituximab as well as its pharmacokinetics in combination with intraventricular methotrexate (MTX). Secondary goals are to obtain information regarding the efficacy of this approach in the treatment of patients with recurrent CNS lymphoma, (brain parenchyma, intraocular or the leptomeningeal compartment).

Thirteen patients with recurrent/refractory CD20+ CNS NHL were treated at UCSF, Dana Farber Cancer Institute and Massachusetts General Hospital on a phase I clinical trial involving twice weekly intraventricular rituximab at 10 mg and 25 mg dose levels, administered over a planned four week schedule. Rituximab is combined with MTX (12 mg) during the second intraventricular injection each week. Patients achieving partial response or better were eligible for a second month of combination intraventricular rituximab plus MTX.

No serious treatment-related toxicity has been detected with intraventricular rituximab/MTX at the 10 mg and 25 mg dose levels. The most common treatment-related toxicity was paresthesias (grade 1). One patient exhibited NHL progression outside of the CNS at three weeks and thus was not evaluable for CNS response, and one patient exhibited stable disease. Complete cytologic responses were detected in ten out of thirteen patients at the one-month restaging. Parenchymal responses were detected in three out of six subjects with one partial response within the corpus callosum, and two complete regressions of lesions within temporal lobe and cerebral cortex. One patient with leptomeningeal lymphoma non-responsive to intravenous rituximab and refractory to high-dose intravenous and intrathecal methotrexate, oral temozolomide and intrathecal liposomal cytarabine, obtained a sustained complete response with the intraventricular rituximab/MTX protocol and subsequently was approved for consolidative autologous stem cell transplant. Two patients have participated in extended dosing on protocol without progression for five and eight months respectively. Thus far, there is no evidence for a relationship between FcGR3A polymorphism and therapeutic resistance in a preliminary analysis (n=8 patients). The maximum tolerated dose of intraventricular rituximab with this combination was established as 25 mg. The mean maximum intraventricular rituximab concentration after intraventricular injection of rituximab was 285 microgram/ml at the 10 mg dose level (N=3) and 882 microgram/ml at the 25 mg dose level (N=10); (p<0.038). The rate of Rituximab clearance from the intraventricular compartment at two hours post injection was 30% slower when administered in combination with methotrexate compared to intraventricular rituximab monotherapy (p <0.02).

Intraventricular rituximab/MTX appears to be safe in recurrent CNS NHL. Twelve of thirteen patients completed at least one month of therapy, without any treatment-associated serious adverse events at any of the institutions. Intraventricular administration of methotrexate may significantly attenuate rituximab clearance from the leptomeningeal compartment. There is encouraging evidence for significant activity of intraventricular immuno-chemotherapy in the treatment of drug-resistant CNS NHL, refractory or non-responsive to intravenous rituximab. These results provide strong support for further investigation of this novel therapeutic approach. NCT00221325. Supported by Leukemia and Lymphoma Society and NIH Grant CA13908301.

Off Label Use: We will discuss the off-label use of rituximab within the leptomeningeal compartment to treat recurrent/refractory CNS lymphomas. Advani:Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding.