Continuous plasma resin perfusion for detoxification of methotrexate

Extracorporeal Treatment for Methotrexate Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

Methotrexate is used in the treatment of many malignancies, rheumatological diseases, and inflammatory bowel disease. Toxicity from use is associated with severe morbidity and mortality. Rescue treatments include intravenous hydration, folinic acid, and, in some centers, glucarpidase. We conducted systematic reviews of the literature following published EXtracorporeal TReatments In Poisoning (EXTRIP) methods to determine the utility of extracorporeal treatments in the management of methotrexate toxicity. The quality of the evidence and the strength of recommendations (either "strong" or "weak/conditional") were graded according to the GRADE approach. A formal voting process using a modified Delphi method assessed the level of agreement between panelists on the final recommendations. A total of 92 articles met inclusion criteria. Toxicokinetic data were available on 90 patients (89 with impaired kidney function). Methotrexate was considered to be moderately dialyzable by intermittent hemodialysis. Data were available for clinical analysis on 109 patients (high-dose methotrexate [>0.5 g/m²]: 91 patients; low-dose [≤0.5 g/m²]: 18). Overall mortality in these publications was 19.5% and 26.7% in those with high-dose and low-dose methotrexate-related toxicity, respectively. Although one observational study reported lower mortality in patients treated with glucarpidase compared with those treated with hemodialysis, there were important limitations in the study. For patients with severe methotrexate toxicity receiving standard care, the EXTRIP workgroup: (1) suggested against extracorporeal treatments when glucarpidase is not administered; (2) recommended against extracorporeal treatments when glucarpidase is administered; and (3) recommended against extracorporeal treatments instead of administering glucarpidase. The quality of evidence for these recommendations was very low. Rationales for these recommendations included: (1) extracorporeal treatments mainly remove drugs in the intravascular compartment, whereas methotrexate rapidly distributes into cells; (2) extracorporeal treatments remove folinic acid; (3) in rare cases where fast removal of methotrexate is required, glucarpidase will outperform any extracorporeal treatment; and (4) extracorporeal treatments do not appear to reduce the incidence and magnitude of methotrexate toxicity.

The utility of online haemodiafiltration in methotrexate poisoning

Summary We report a case of a 56-year-old woman with a high-grade diffuse large B-cell lymphoma who unexpectedly developed toxic plasma levels of methotrexate (MTX) following the first cycle of rituximab-cyclophosphamide, hydroxydanorubicin, oncovin, prednisolone (R-CHOP) with a high-dose MTX chemotherapy protocol. She also developed non-oliguric acute kidney injury secondary to MTX nephrotoxicity. We elected to treat her with online-haemodiafiltration (HDF) and this proved to be efficient with a dramatic response. Rapid clearance of MTX to therapeutic levels was possible within three sessions. Prompt therapy with high-volume online-HDF is an effective choice for rapid MTX clearance and swift reversal of MTX nephrotoxicity.

Understanding and managing methotrexate nephrotoxicity

Methotrexate (MTX) is one of the most widely used anti-cancer agents, and administration of high-dose methotrexate (HDMTX) followed by leucovorin (LV) rescue is an important component in the treatment of a variety of childhood and adult cancers. HDMTX can be safely administered to patients with normal renal function by the use of alkalinization, hydration, and pharmacokinetically guided LV rescue. Despite these measures, HDMTX-induced renal dysfunction continues to occur in approximately 1.8% of patients with osteosarcoma treated on clinical trials. Prompt recognition and treatment of MTX-induced renal dysfunction are essential to prevent potentially life-threatening MTX-associated toxicities, especially myelosuppression, mucositis, and dermatitis. In addition to conventional treatment approaches, dialysis-based methods have been used to remove MTX with limited effectiveness. More recently carboxypeptidase-G(2) (CPDG(2)), a recombinant bacterial enzyme that rapidly hydrolyzes MTX to inactive metabolites, has become available for the treatment of HDMTX-induced renal dysfunction. CPDG(2) administration has been well tolerated and resulted in consistent and rapid reductions in plasma MTX concentrations by a median of 98.7% (range, 84%-99.5%). The early administration of CPDG(2) in addition to LV may be beneficial for patients with MTX-induced renal dysfunction and significantly elevated plasma MTX concentrations.

High-dose methotrexate-associated acute renal failure may be an avoidable complication

A 17-year-old boy with acute lymphoblastic leukemia developed acute renal failure within 48 h of an intravenous high-dose methotrexate (5 g/m2) infusion. His renal function returned to baseline 14 days later with supportive care, folinic acid rescue, and urinary alkalinization. A retrospective review revealed that the patient had been exposed to iopamidol, an intravenous contrast medium, on the day prior to the commencement of methotrexate treatment. Methotrexate-associated nephropathy is a rare complication in pediatric oncology, and a review of the literature suggests that exposure to nephrotoxic agents may be a significant but perhaps underrecognized risk factor for its development.

Carboxypeptidase-G2 rescue in a patient with high dose methotrexate-induced nephrotoxicity

A 13 year-old girl with osteosarcoma and pulmonary tumor recurrence developed acute renal failure following high dose methotrexate (12 g/m(2)) therapy, she had previously tolerated high dose methotrexate and her renal and hepatic functions were normal. Briefly, 48 hours after beginning methotrexate infusion her methotrexate concentration and creatinine level were 1338.8 microM/L and 5.8 mg/dl, respectively. Grade IV oral mucositis and neutropenia with fever developed at 144 hours after MTX infusion. Hydration and alkalinization were continued and leucovorin rescue was intensified based on the plasma MTX concentrations. Plasma exchange was performed twice and hemodialysis 3 times without problems, but methotrexate and creatinine levels remained high, 91.9 microM/L, and 2.5 mg/dl, respectively. After 3 courses of hemodialysis carboxypeptidase-G2 (CPDG2) was administered at 50 U/kg, intravenously over 5 minutes. After 15 minutes of CPDG2 (Voraxaze) infusion, her plasma MTX concentration was 0.91 microM/L and no rebound elevation or side effects developed. Thirteen days post-MTX infusion her renal function had normalized. We report here our experience of a dramatic methotrexate level reduction caused by CPDG2 administration.

High-dose methotrexate-induced nephrotoxicity in patients with osteosarcoma

BACKGROUND

High-dose methotrexate (HDMTX)-induced renal dysfunction can be life threatening, because it delays methotrexate (MTX) excretion, thereby exacerbating the other toxicities of MTX. HDMTX-induced nephrotoxicity has been managed with high-dose leucovorin, dialysis-based methods of MTX removal, thymidine, and with the recombinant enzyme, carboxypeptidase-G2 (CPDG2), which cleaves MTX to inactive metabolites. The objectives of the current study were to estimate the current incidence of HDMTX-induced renal dysfunction in patients with osteosarcoma and to compare the efficacy and recovery of renal function for dialysis-based methods of MTX removal with treatment using CPDG2.

METHODS

The literature was reviewed for osteosarcoma trials, use of dialysis-based methods for MTX removal, and reports of MTX-induced nephrotoxicity, including information regarding recovery of renal function. Clinical trial databases of select osteosarcoma studies were reviewed. The efficacy of CPDG2 and renal recovery after CPDG2 rescue was obtained from the database of a compassionate-release trial.

RESULTS

Approximately 1.8% of patients with osteosarcoma (68 of 3887 patients) who received HDMTX developed nephrotoxicity Grade >/= 2. The mortality rate among those patients was 4.4% (3 of 68 patients). Dialysis-based methods of MTX removal were used frequently but had limited effectiveness in removing MTX compared with the rapid reductions > 98% in plasma MTX concentrations achieved with CPDG2. CPDG2 did not appear to increase the time to recovery of renal function compared with supportive treatment that included dialysis-based methods.

CONCLUSIONS

HDMTX-induced renal dysfunction continues to occur in approximately 1.8% of patients with osteosarcoma who are treated on clinical protocols with optimal supportive care. For patients with delayed MTX excretion and high plasma MTX concentrations, CPDG2 should be considered over hemodialysis to lower plasma MTX concentrations rapidly and efficiently.

Coupled Plasma Filtration Adsorption: Rationale, Technical Development and Early Clinical Experience

The adjuvant treatment of sepsis remains a major therapeutic challenge. Blood purification is theoretically appealing if the humoral theory of sepsis is accepted as the basis for intervention. In this setting, blood purification would provide a broad-based restoration of humoral homeostasis thereby avoiding both excessive inflammation and counterinflammation. Several techniques of blood purification have been tried or are under active investigation. One of these is the so-called coupled plasma filtration adsorption (CPFA). CPFA is a novel extracorporeal blood purification therapy aimed at nonselectively reducing the circulating levels and activities of both pro- and anti-inflammatory mediators during sepsis and multiorgan failure. In vitro studies have shown CPFA to be effective in binding a broad range of such mediators proving its technical efficacy. Subsequent animal models have shown a beneficial effect on survival in endotoxemia. These studies have provided the necessary technical developments and biologic rationale for initial human studies. Two phase I/IIa clinical studies have now been performed. Both studies have shown that CPFA improves blood pressure and restores immune function in patients with severe sepsis and multiorgan dysfunction. In this article, we will discuss some of the basic principles involved in sorbent technology, and how these may contribute to treatment efficacy, review animal experiments with CPFA and finally discuss the results of recent human studies and their implications.