Resumption of high-dose methotrexate after methotrexate-induced nephrotoxicity and carboxypeptidase G2 use

A second administration of glucarpidase in a different cycle of high-dose methotrexate: Is it safe and effective in adults?

INTRODUCTION

Methotrexate intoxication following high-dose methotrexate-induced acute kidney injury is a life-threatening complication. Glucarpidase can quickly reduce extracellular methotrexate to safe levels, but the effectiveness and safety of its use in different episodes of nephrotoxicity remain an unknown area.

CASE REPORT

A 30-year-old male diagnosed with acute lymphoblastic T-cell lymphoma received methotrexate 5 g/m2 intravenous (IV) as part of the first consolidation cycle. On Consolidation 3, he restarted methotrexate at a dose of 3 g/m2 IV showing slow methotrexate elimination, associated myelosuppression, and hepatic toxicity. Glucarpidase was administered (total dose of 2000 International Units (IU)). No adverse events were observed, and his renal function returned to normal. One hundred and six days later, he was diagnosed with leptomeningeal and cerebellar relapse and treatment with methotrexate 3,5 g/m2 IV day 1 and cytosine arabinoside (Ara-C) 2 g/m2 IV twice per day days 1, 3, and 5 was started. At 36 h from methotrexate infusion, serum creatinine increased up to 1.89 mg/dL and methotrexate concentration was 100 µmol/L.Management and Outcome: Ara-C was suspended, and a second administration of glucarpidase (2000 IU) was dispensed. No adverse events were noticed, methotrexate levels decreased and renal function progressively improved, recovering completely three weeks later.

DISCUSSION

The effectiveness and safety of the use of glucarpidase in different episodes of nephrotoxicity remain an unknown area, and the rate and consequences of antiglucarpidase antibody formation remain poorly understood. This case report is, to our knowledge, the first case of a second administration of glucarpidase in a different cycle of high-dose methotrexate in an adult patient.

In vitro synergy of azole antifungals and methotrexate against Candida albicans

OBJECTIVE

This study aims to evaluate the effective of azoles and MTX for patients with invasive candidiasis.

METHODS

We used the disk diffusion assay and the checkerboard assay to evaluate the in vitro interactions between MTX and antifungals. In addition, we used the transmission electron microscopy to observe the ultrastructure of the effect of MTX and fluconazole on Candida albicans.

RESULTS

The rates of synergy for the combination of MTX with fluconazole (FLC), itraconazole (ITC), and voriconazole (VRZ) were 91.3%, 65.2%, and 87% in checkerboard testing. No antagonism was found between methotrexate and azole antifungals in any of the strains. Furthermore, MTX treated C. albicans showed extensive cell wall vacuolations and the inhibition of blastospores growth, as observed using transmission electron microscopy. There was an apparent destruction of the cell membrane and cell wall resulting in the destruction of cytoplasm, a phenomenon observed when MTX was combined with azoles.

CONCLUSION

This study provides evidence that the combination of azoles and MTX is effective for patients with invasive candidiasis, which on the other hand, will reduce the side effects of the drugs.

Length of stay, mortality, and readmissions among Medicare cancer patients treated with glucarpidase and conventional care: a retrospective study

PURPOSE

Glucarpidase (Voraxaze) is used to treat methotrexate (Mtx) toxicity in patients with delayed Mtx clearance due to impaired renal function. We examine hospital length of stay (LOS), mortality, and readmission rates for Medicare cancer patients with delayed clearance of Mtx treated with glucarpidase.

METHODS

Using 2010-2017 Medicare claims data, we identified glucarpidase patients as those hospitalized with indications of select lymphomas or leukemia, inpatient chemotherapy, and glucarpidase treatment. We assessed outcomes of glucarpidase patients relative to those experienced by patients treated for presumed Mtx toxicity using other therapies. These nonglucarpidase patients were identified with a diagnosis of primary central nervous system lymphoma, indications of cancer-chemotherapy toxicity, and acute kidney injury during hospitalization (not present on admission), and were divided into two groups: treated with dialysis (dialysis+) and treated with or without dialysis (dialysis+/-). Inverse-probability treatment weighting using propensity scores was used to adjust for differences between groups.

RESULTS

Patients treated with glucarpidase (n=30) had an average LOS of 14.7 days. They had inpatient, 30-day, and 90-day mortality rates of 3.3%, 13.3%, and 16.7%, respectively, and a 90-day all-cause unplanned readmission rate of 24.1%. The dialysis+ and dialysis+/- groups, respectively, had higher average LOS (40.2, 21.9), higher inpatient mortality (50.6%, 20.8%), and higher 90-day mortality (58.6%, 37.6%). No statistically significant differences in 30-day mortality or 90-day readmission rates were detected between the glucarpidase group and either of the nonglucarpidase groups. Unobservable differences in patient severity may impact the interpretation of our findings.

CONCLUSION

Medicare cancer patients with presumed Mtx toxicity receiving conventional treatment experience long hospitalizations, high intensive-care unit use and high mortality. Glucarpidase patients had lower LOS, inpatient mortality, and 90-day mortality than the non-glucarpidase patients.

Comparable efficacy with varying dosages of glucarpidase in pediatric oncology patients

BACKGROUND

Glucarpidase rapidly reduces methotrexate plasma concentrations in patients experiencing methotrexate-induced renal dysfunction. Debate exists regarding the role of glucarpidase in therapy given its high cost. The use of reduced-dose glucarpidase has been reported, and may allow more institutions to supply this drug to their patients. This report explores the relationship between glucarpidase dosage and patient outcomes in pediatric oncology patients.

METHODS

The authors evaluated data from 26 patients who received glucarpidase after high-dose methotrexate. Decrease in plasma methotrexate concentrations and time to renal recovery were evaluated for an association with glucarpidase dosage, which ranged from 13 to 90 units/kg.

RESULTS

No significant relationship was found between glucarpidase dosage (units/kg) and percent decrease in methotrexate plasma concentrations measured by TDx (P > 0.1) or HPLC (P > 0.5). Patients who received glucarpidase dosages <50 units/kg had a median percent reduction in methotrexate plasma concentration of 99.4% (range, 98-100) measured by HPLC compared to a median percent reduction of 99.4% (range, 77.2-100) in patients who received ≥50 units/kg. Time to SCr recovery was not related to glucarpidase dosage (P > 0.8).

CONCLUSIONS

The efficacy of glucarpidase in the treatment of HDMTX-induced kidney injury was not dosage-dependent in this retrospective analysis of pediatric oncology patients.

Resumption of high-dose methotrexate after acute kidney injury and glucarpidase use in pediatric oncology patients

BACKGROUND

High-dose methotrexate (HDMTX)-induced acute kidney injury is a rare but life-threatening complication. The methotrexate rescue agent glucarpidase rapidly hydrolyzes methotrexate to inactive metabolites. The authors retrospectively reviewed glucarpidase use in pediatric cancer patients at their institution and evaluated whether subsequent resumption of HDMTX was tolerated.

METHODS

Clinical data and outcomes of all patients who received glucarpidase after HDMTX administration were reviewed.

RESULTS

Of 1141 patients who received 4909 courses of HDMTX, 20 patients (1.8% of patients, 0.4% of courses) received 22 doses of glucarpidase. The median glucarpidase dose was 51.6 U/kg (range, 13-65.6 U/kg). At the time of administration, the median plasma methotrexate concentration was 29.1 μM (range, 1.3-590.6 μM). Thirteen of the 20 patients received a total of 39 courses of HDMTX therapy after glucarpidase. The median time to complete methotrexate excretion was 355 hours (range, 244-763 hours) for the HDMTX course during which glucarpidase was administered, 90 hours (range, 66-268 hours) for the next HDMTX course, and 72 hours (range, 42-116 hours) for subsequent courses. The median peak serum creatinine level during these HDMTX courses was 2.2 mg/dL (range, 0.8-9.6 mg/dL), 0.8 mg/dL (range, 0.4-1.6 mg/dL), and 0.6 mg/dL (range, 0.4-0.9 mg/dL), respectively. One patient experienced nephrotoxicity upon rechallenge with HDMTX. Renal function eventually returned to baseline in all patients, and no patient died as a result of methotrexate toxicity.

CONCLUSIONS

The current results indicated that it is possible to safely resume HDMTX therapy after glucarpidase treatment for HDMTX-induced acute kidney injury.

Glucarpidase, leucovorin, and thymidine for high-dose methotrexate-induced renal dysfunction: clinical and pharmacologic factors affecting outcome

PURPOSE

To assess the role of the recombinant bacterial enzyme, glucarpidase (carboxypeptidase-G(2)), leucovorin, and thymidine in the management and outcome of patients with high-dose methotrexate (HDMTX) -induced nephrotoxicity.

METHODS

Patients with HDMTX-induced nephrotoxicity received one to three doses of intravenous (IV) glucarpidase and leucovorin rescue. The initial cohort (n = 35) also received thymidine by continuous IV infusion. Subsequently, thymidine was restricted to patients with prolonged exposure (> 96 hours) to methotrexate (MTX) or with substantial MTX toxicity at study entry. Plasma MTX, leucovorin, and 5-methyltetrahydrofolate (5-mTHF) concentrations were measured pre- and postglucarpidase. Toxicities were monitored, and logistic regression analysis was used to assess the relationship of baseline characteristics to the development of severe toxicity and death.

RESULTS

Glucarpidase was administered at a median of 96 hours (receiving thymidine, n = 44) and 66 hours (not receiving thymidine, n = 56) after the start of the MTX infusion. Plasma MTX concentrations decreased within 15 minutes of glucarpidase by 98.7%. Plasma 5-mTHF concentrations also decreased more than 98% after administration of glucarpidase. Of 12 deaths, six were directly attributed to irreversible MTX toxicity. Presence of grade 4 toxicity before administration of glucarpidase, inadequate initial increase in leucovorin dosing, and administration of glucarpidase more than 96 hours after the start of the MTX infusion were associated with development of grade 4 and 5 toxicity.

CONCLUSION

Early intervention with the combination of leucovorin and glucarpidase is highly effective in patients who develop HDMTX-induced renal dysfunction. Severe toxicity and mortality occurred in patients in whom glucarpidase rescue was delayed and occurred despite thymidine administration.

Glucarpidase rescue in a patient with high-dose methotrexate-induced nephrotoxicity

PURPOSE

To describe the successful use of glucarpidase (carboxypeptidase G2) in the treatment of high-dose methotrexate-induced nephrotoxicity in a patient with osteosarcoma.

SUMMARY

A 12-year-old female patient who had been diagnosed with low-grade right mandibular osteosarcoma was started on a protocol of cisplatin plus doxorubicin alternating with high-dose methotrexate. Following her first dose of methotrexte, she developed acute renal failure and higher than expected 24h methotrexate level of 478μM/L. High-dose leucovorin rescue was started with vigorous hydra- tion and urine alkalinization together with two sessions of hemodialysis. Because her methotrexate level was persistently high, the investigational drug glucarpidase was administered. Methotrexate level dropped from 65 to 16.3 μM/L after a single dose of glucarpidase measured by fluorescence polarization immunoassay. Leucovorin and urine alkalinization were continued until day 17 when the patient's kidney function normalized and methotrexate level reached 0.05 μM/L. The patient tolerated glucarpidase well without any significant adverse events.

CONCLUSION

Glucarpidase is a safe and effective agent in the management of high-dose methotrexate-induced nephrotoxicity and delayed methotrexate elimination.