Managing reduced methotrexate clearance in a patient with a heterozygous methylenetetrahydrofolate reductase gene polymorphism.

High dose methotrexate has become one of the treatments of choice for patients with primary CNS lymphomas due to its ability to penetrate the blood-brain barrier. A potentially serious complication of this therapy is methotrexate-related nephrotoxicity. We report the case of a patient with a common genetic polymorphism that may have predisposed this patient experience clinically significant toxicity from systemic folate depletion. After the first cycle of chemotherapy that included high dose methotrexate, the patient's serum creatinine rose and the patient's methotrexate level remained above the toxic range for six days. On cycle two, the patient was treated with a 25% dose reduction in methotrexate and more aggressive hydration and alkalization. With this alteration in the regimen, the patient was able to receive six more cycles and had a complete radiographic tumor response in the brain and a disappearance of tumor cells in the CSF without any further renal complications. This case report illustrates the feasibility of administering high dose methotrexate with modifications as a treatment of choice in individuals with methylenetetrahydrofolate reductase gene mutations.

Intrathecal topotecan in adult patients with neoplastic meningitis.

PURPOSE: The efficacy and safety of intrathecal topotecan were assessed in patients with neoplastic meningitis (NM) by retrospective chart review. SUMMARY: Fourteen patients (median age, 57 years) with NM were treated with the standard of care (i.e., regional or systemic chemotherapy or irradiation or both) plus intrathecal topotecan between January 2004 and September 2005. Three patients developed NM in the setting of systemic cancer; 11 patients had primary central nervous system (CNS) malignancies. All patients received 0.4 mg of topotecan intrathecally two times per week. The efficacy of intrathecal topotecan was assessed on the basis of the number of doses to cerebrospinal fluid (CSF) cytologic clearing--defined as the disappearance of malignant cells from a previously positive CSF cytology. Safety was evaluated by chart documentation of adverse events that might have been associated with topotecan given intrathecally. Of the 11 patients with primary CNS tumors, 6 patients achieved CSF clearing after the first dose of intrathecal topotecan, 2 patients after the second dose, and 1 patient after the fifth dose. For the 3 patients with secondary CSF tumors, 1 patient achieved CSF clearing after the third dose and 2 patients did not reach the primary endpoint. Overall, 6 of the 14 patients achieved CSF clearing after the first dose of intrathecal topotecan; in 10 of the 14 patients, CSF clearing of malignant cells was observed at some point during treatment. Toxicity was modest. The most common adverse effect reported was fatigue. CONCLUSION: Intrathecal topotecan appeared to be effective and safe in adult patients with NM.

Reduced-dose rasburicase in the treatment of adults with hyperuricemia associated with malignancy.

Tumor lysis syndrome is a life-threatening complication of chemotherapy for patients with leukemia and large tumors with a high proliferative index, such as Burkitt's lymphoma. The syndrome is characterized by hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia. The standard of care for hyperuricemia consists of hydration with or without alkalinization and administration of allopurinol. When treated in this manner, patients often experience persistent hyperuricemia that lasts several days after the start of antineoplastic therapy; sometimes they develop uric acid nephropathy as a consequence. Rasburicase, a recombinant urate oxidase enzyme, quickly removes large amounts of uric acid from plasma. The drug is approved by the United States Food and Drug Administration for management of elevated plasma uric acid levels in pediatric patients with leukemia, lymphoma, or solid tumor malignancies who are receiving chemotherapy. We undertook a retrospective review of adult patients treated with a single dose of rasburicase 6 mg for hyperuricemia associated with malignancy. Ten patients received one 6-mg dose of rasburicase, and one patient received two 6-mg doses as an adjuvant therapy to normalize uric acid levels. In most of the patients, a single 6-mg dose of rasburicase was effective in correcting uric acid levels in the typical time between diagnosis and start of antineoplastic therapy.