Most lymphomas that involve the central nervous system are B-cell neoplasms that express the cell surface molecule CD20. After intravenous administration, rituximab can be reproducibly measured in the cerebrospinal fluid (CSF) in patients with primary central nervous system lymphoma; however, the CSF levels of rituximab are approximately 0.1% of serum levels associated with therapeutic activity in patients with systemic non-Hodgkin lymphoma. Because lymphomatous meningitis is a frequent complication of nonHodgkin lymphoma, we have conducted an analysis of the safety and pharmacokinetics of direct intrathecal administration of rituximab using cynomolgus monkeys. No significant acute or delayed toxicity, neurologic or otherwise, was detected. Pharmacokinetic analysis suggests that drug clearance from the CSF is biphasic, with a terminal half-life of 4.96 hours. A phase 1 study to investigate the safety and pharmacokinetics of intrathecal rituximab in patients with recurrent lymphomatous meningitis will be implemented based on these findings. ( IntroductionCentral nervous system (CNS) involvement is associated with an adverse outcome in patients with non-Hodgkin lymphoma (NHL). 1 Most NHLs that involve the CNS are B-cell neoplasms that express CD20. 2 Dissemination within the leptomeninges represents a common pathway of progression in systemic NHL and primary CNS lymphoma and usually heralds neurologic deterioration and a fatal outcome. 3 Rituximab monoclonal antibody therapy is an effective treatment for B-cell NHL. [4][5][6][7] To date, preclinical and clinical practice involving rituximab has been limited to intravenous administration. This agent binds specifically to the antigen CD20, which is expressed on more than 90% of B-cell NHL and primary CNS lymphoma but is not expressed by normal neurons or glia in the brain.A number of preclinical models have demonstrated that therapeutic antibodies administered into the cerebrospinal fluid (CSF) are able to concentrate in and eradicate tumors within the craniospinal axis with minimal toxicity. 8,9 The primate model of drug delivery into the CSF represents a valid experimental model for the prediction of CSF drug pharmacokinetics in humans. [10][11][12][13] This is the first preclinical analysis of the safety and pharmacokinetics of rituximab administration within the craniospinal axis. Study designAll experimental procedures have been reviewed and approved by the Committee on Human Research and by the Committee on Animal Research, University of California, San Francisco.Four female cynomolgus monkeys, aged 16 to 18 years, weighing 3 to 5 kg, were obtained from Biosurg (Winters, CA). A total of 7 experiments were performed with one monkey in each experiment. Data are reported from the 4 experiments that involved suboccipital administration of rituximab. Three experiments used an Ommaya reservoir (Integra NeuroCare, Plainsboro, NJ) in the right lateral ventricle. Although intra-Ommaya administration of rituximab resulted in high CSF concentrations, the size of the res...

In 1983, the Northern California Oncology Group (NCOG) instituted a randomized trial of intravenous (IV) versus intraarterial (IA) floxuridine (FUDR) administered via an implantable pump for patients with colorectal cancer metastatic to the liver. The study objectives were to compare the hepatic response rate, time to hepatic progression, and toxicity for the two treatment arms. The study design, which allowed patients failing IV FUDR to crossover to the IA arm, prevents a meaningful comparative analysis of survival. Patients with liver-only metastases (N = 143) were randomized, 76 to the IV arm and 67 to the IA arm, and 115 patients (65 IV, 50 IA) were fully evaluable. Of the 65 patients in the IV arm, 28 crossed over to IA treatment after failing IV FUDR. The dose-limiting toxicity of IV FUDR was diarrhea, whereas biliary toxicity limited both the dose and duration of IA FUDR therapy. Of the first 25 patients treated with IA FUDR at a dose of .3 mg/kg/day, 10 developed radiographically evident biliary strictures, and three developed permanent jaundice. With reduction of the initial IA FUDR dose to .2 mg/kg/day, and adoption of a policy of early dosage reduction, treatment interruption, or termination of therapy for persistent elevations in alkaline phosphatase, only two further cases of serious biliary toxicity occurred. However, 26 of the 50 IA FUDR patients ultimately had therapy terminated because of drug toxicity rather than disease progression. When compared with systemic infusion, infusion into the hepatic artery greatly enhanced the antitumor activity of FUDR against colorectal liver metastases. Although biliary toxicity is the most serious limitation of this form of therapy, biliary stricture and jaundice usually can be averted through careful monitoring of liver enzymes and early dosage reduction.

BCOPs can contribute to a projected shortfall in needed patient visits for cancer treatment. BCOPs, along with nurse practitioners and physician assistants could substantially reduce, but likely not eliminate, the shortfall of providers needed for oncology patient visits.