Prophylactic Trimethoprim-Sulfamethoxazole Does Not Affect Pharmacokinetics or Pharmacodynamics of Methotrexate

Impact of Prophylactic Trimethoprim-Sulfamethoxazole on Clearance of High-Dose Methotrexate in Adult Patients

PURPOSE

High-dose methotrexate (HDMTX) is an antineoplastic dosing strategy used to treat various cancers including primary central nervous system lymphoma. Trimethoprim-sulfamethoxazole (TMP/SMX) is commonly used for antibiotic prophylaxis against Pneumocystis pneumonia infections in this patient population. Significant drug-drug interactions between TMP/SMX and methotrexate (MTX) leading to adverse outcomes have been documented, primarily in adult patients taking MTX for rheumatologic conditions.

METHODS

This study is a single-center, retrospective, cohort study comparing outcomes in patients where TMP/SMX was held during HDMTX and patients who received concurrent prophylactic TMP/SMX during treatment. The primary end point was mean MTX level at 24, 48, and 72 hours. Secondary end points included rate of nonhematologic toxicity, rate of hematologic toxicity, median days to MTX clearance, and frequency of glucarpidase utilization.

RESULTS

In total, 248 cycles of HDMTX were analyzed from 221 individual patients. One hundred ninety-one cycles were administered without prophylactic TMP/SMX, and 57 were administered with TMP/SMX. The median MTX level at 24, 48, and 72 hours in those without versus with prophylactic TMP/SMX was 4.30 versus 4.30, 0.29 versus 0.30, and 0.14 versus 0.15, respectively. Similarly, rates of hematologic and nonhematologic toxicities did not differ significantly between groups with the exception of neutropenia; however, there was no corresponding increased rate of neutropenic fever. Only one patient received glucarpidase and had not received TMP/SMX.

CONCLUSION

Prophylactic TMP/SMX had minimal interaction with HDMTX and does not lead to increased time to clearance or clinically relevant toxicities. Prophylactic TMP/SMX can be safely administered with HDMTX in adult patients.

EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update

BACKGROUND

Since the publication of the EULAR recommendations for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in 2016, several randomised clinical trials have been published that have the potential to change clinical care and support the need for an update.

METHODS

Using EULAR standardised operating procedures, the EULAR task force undertook a systematic literature review and sought opinion from 20 experts from 16 countries. We modified existing recommendations and created new recommendations.

RESULTS

Four overarching principles and 17 recommendations were formulated. We recommend biopsies and ANCA testing to assist in establishing a diagnosis of AAV. For remission induction in life-threatening or organ-threatening AAV, we recommend a combination of high-dose glucocorticoids (GCs) in combination with either rituximab or cyclophosphamide. We recommend tapering of the GC dose to a target of 5 mg prednisolone equivalent/day within 4-5 months. Avacopan may be considered as part of a strategy to reduce exposure to GC in granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). Plasma exchange may be considered in patients with rapidly progressive glomerulonephritis. For remission maintenance of GPA/MPA, we recommend rituximab. In patients with relapsing or refractory eosinophilic GPA, we recommend the use of mepolizumab. Azathioprine and methotrexate are alternatives to biologics for remission maintenance in AAV.

CONCLUSIONS

In the light of recent advancements, these recommendations provide updated guidance on AAV management. As substantial data gaps still exist, informed decision-making between physicians and patients remains of key relevance.

Methotrexate-induced Severe Pancytopenia in a Patient with Rheumatoid Arthritis: A Case Report and Review of Literature

Toxicity associated with low doses of methotrexate (MTX) is low, but it may be fatal. Bone marrow suppression and mucositis are among the common side effects of low dose MTX toxicity. Different risk factors have been reported for toxicities associated with low doses of MTX, including accidental use of higher doses, renal dysfunction, hypoalbuminemia, and polypharmacy. In this paper, we present a female patient who had mistakenly used 7.5 mg of MTX daily instead of the same dose of MTX on Thursday and Friday. She was presented with mucositis and diarrhea to the emergency department. Moreover, we searched the databases Scopus and PubMed for available studies and case reports on toxicities associated with MTX dosing errors. The most frequently observed toxicities included gastrointestinal lesions, nausea, vomiting, skin lesions, and bone marrow suppression. Leucovorin, hydration, and urine alkalinization were among the most frequently used treatments. Finally, we summarize the data on the toxicities of low doses of MTX in different diseases.

Methotrexate for inflammatory skin disease in pediatric patients: Consensus treatment guidelines

Methotrexate (MTX) is a readily accessible drug, first used in 1948 and employed for a wide variety of indications since then. However, despite widespread off-label use, FDA labeling does not include approved indications for the use of MTX for many inflammatory skin diseases in pediatric patients, including morphea, psoriasis, atopic dermatitis, and alopecia areata, among others. Without published treatment guidelines, some clinicians may be hesitant to use MTX off-label, or uncomfortable prescribing MTX in this population. To address this unmet need, an expert consensus committee was convened to develop evidence- and consensus-based guidelines for use of MTX to treat pediatric inflammatory skin disease. Clinicians with experience and expertise in clinical research, drug development, and treating inflammatory skin disease in pediatric patients with MTX were recruited. Five committees were created based on major topic areas: (1) indications and contraindications, (2) dosing, (3) interactions with immunizations and medications, (4) adverse effects (potential for and management of), and (5) monitoring needs. Pertinent questions were generated and addressed by the relevant committee. The entire group participated in a modified Delphi process to establish agreement on recommendations for each question. The committee developed 46 evidence- and consensus-based recommendations, each with >70% agreement among members, across all five topics. These are presented in tables and text, along with a discussion of supporting literature, and level of evidence. These evidence- and consensus-based recommendations will support safe and effective use of MTX for the underserved population of pediatric patients who may benefit from this valuable, time-honored medication.

[Practical management during maintenance therapy of pediatric acute lymphoblastic leukemia: Recommendations of the French Society for Childhood and Adolescent Cancer and Leukemia (SFCE)]

Maintenance therapy is the last phase of treatment for acute lymphoblastic leukemia in children and adolescents. Although maintenance therapy is associated with toxicities and specific management issues, it is an essential phase of treatment that reduces the risk of relapse. The objective of this work is to propose a guide for the initiation, administration, and monitoring of maintenance therapy, and for the management of food, schooling, leisure, community life, risk of infection and links with family medicine.

UK paediatric oncology Pneumocystis jirovecii pneumonia surveillance study

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is a serious infective complication of immunosuppressive therapy. There are insufficient data concerning the incidence or mortality rate in children undergoing treatment for malignancies and how these may be influenced by prophylaxis.

OBJECTIVE

Prospective collection of clinical information for all suspected and proven cases of PJP in children with cancer in the UK and Ireland.

DESIGN

A surveillance survey was undertaken using a key contact at each paediatric oncology Principle Treatment Centre (PTC).

MAIN OUTCOME MEASURES

To describe the mortality, outcomes and use of prophylaxis in this at-risk group.

RESULTS

The study confirms that PJP is rare, with only 32 cases detected in the UK over a 2-year period reported from all 20 PTCs. No deaths were directly attributed to PJP, in contrast to previously reported high mortality rates. Breakthrough infection may occur despite prescription of ostensibly adequate prophylaxis with co-trimoxazole; 11 such cases were identified. Six infections occurred in patients for whom prophylaxis was not thought to be indicated. Two infections occurred in patients for whom prophylaxis was specifically omitted due to concerns about potential bone marrow suppression or delayed engraftment.

CONCLUSION

PJP in children treated for malignant disease is rare. Breakthrough infection despite prophylaxis with co-trimoxazole may represent pathogen resistance or non-compliance. Further consideration of the use of PJP prophylaxis during acute myeloid leukaemia and non-Hodgkin's lymphoma treatment is warranted, alongside appraisal of the clinical implications of the possible marrow suppressive effects of co-trimoxazole and its interactions with methotrexate.

MTXPK.org: A Clinical Decision Support Tool Evaluating High-Dose Methotrexate Pharmacokinetics to Inform Post-Infusion Care and Use of Glucarpidase

Methotrexate (MTX), an antifolate, is administered at high doses to treat malignancies in children and adults. However, there is considerable interpatient variability in clearance of high‐dose (HD) MTX. Patients with delayed clearance are at an increased risk for severe nephrotoxicity and life‐threatening systemic MTX exposure. Glucarpidase is a rescue agent for severe MTX toxicity that reduces plasma MTX levels via hydrolysis of MTX into inactive metabolites, but is only indicated when MTX concentrations are > 2 SDs above the mean excretion curve specific for the given dose together with a significant creatinine increase (> 50%). Appropriate administration of glucarpidase is challenging due to the ambiguity in the labeled indication. A recent consensus guideline was published with an algorithm to provide clarity in when to administer glucarpidase, yet clinical interpretation of laboratory results that do not directly correspond to the algorithm prove to be a limitation of its use. The goal of our study was to develop a clinical decision support tool to optimize the administration of glucarpidase for patients receiving HD MTX. Here, we describe the development of a novel 3‐compartment MTX population pharmacokinetic (PK) model using 31,672 MTX plasma concentrations from 772 pediatric patients receiving HD MTX for the treatment of acute lymphoblastic leukemia and its integration into the online clinical decision support tool, MTXPK.org. This web‐based tool has the functionality to utilize individualized demographics, serum creatinine, and real‐time drug concentrations to predict the elimination profile and facilitate model‐informed administration of glucarpidase.

Consensus Guideline for Use of Glucarpidase in Patients with High-Dose Methotrexate Induced Acute Kidney Injury and Delayed Methotrexate Clearance

An expert panel was convened to provide specific, expert consensus guidelines for the use of glucarpidase in patients who develop high‐dose methotrexate (HDMTX)‐induced nephrotoxicity and delayed methotrexate excretion. This guideline provides recommendations to identify the population of patients who would benefit from glucarpidase rescue by more precisely defining the absolute methotrexate concentrations associated with risk for severe or life‐threatening toxicity at several time points after the start of a HDMTX infusion.

Acute kidney injury due to high‐dose methotrexate (HDMTX) is a serious, life‐threatening toxicity that can occur in pediatric and adult patients. Glucarpidase is a treatment approved by the Food and Drug Administration for high methotrexate concentrations in the context of kidney dysfunction, but the guidelines for when to use it are unclear. An expert panel was convened to provide specific, expert consensus guidelines for the use of glucarpidase in patients who develop HDMTX‐induced nephrotoxicity and delayed methotrexate excretion. The guideline provides recommendations to identify the population of patients who would benefit from glucarpidase rescue by more precisely defining the absolute methotrexate concentrations associated with risk for severe or life‐threatening toxicity at several time points after the start of an HDMTX infusion. For an HDMTX infusion ≤24 hours, if the 36‐hour concentration is above 30 µM, 42‐hour concentration is above 10 µM, or 48‐hour concentration is above 5 µM and the serum creatinine is significantly elevated relative to the baseline measurement (indicative of HDMTX‐induced acute kidney injury), glucarpidase may be indicated. After a 36‐ to 42‐hour HDMTX infusion, glucarpidase may be indicated when the 48‐hour methotrexate concentration is above 5 µM. Administration of glucarpidase should optimally occur within 48–60 hours from the start of the HDMTX infusion, because life‐threatening toxicities may not be preventable beyond this time point.

Implications for Practice.

Glucarpidase is a rarely used medication that is less effective when given after more than 60 hours of exposure to high‐dose methotrexate, so predicting early which patients will need it is imperative. There are no currently available consensus guidelines for the use of this medication. The indication on the label does not give specific methotrexate concentrations above which it should be used. An international group of experts was convened to develop a consensus guideline that was specific and evidence‐based to identify the population of patients who would benefit from glucarpidase.

Drug-drug interactions in pediatric oncology patients

BACKGROUND

Drug-drug interactions (DDIs) can negatively affect pharmacotherapy. However, pediatric DDI studies are scarce. We undertook an exploratory study to investigate prevalence and clinical relevance of DDIs between cytostatic and noncytostatic drugs in outpatient pediatric oncology patients.

PROCEDURE

After informed consent and inclusion, the following information was collected: currently prescribed noncytostatic and cytostatic drugs, comorbidities, and use of over-the-counter (OTC) drugs, complementary and alternative medicines (CAMs), and dietary supplements. All medication was screened for DDIs according to two databases: Micromedex^® Solutions and the Dutch drug database G-Standard. The researcher presented DDIs with an associated potential for adverse outcome and a proposal for intervention to three independent experts. If the experts considered a DDI to be potentially clinically relevant and requiring intervention, the physician was notified.

RESULTS

Seventy-three patients were included (median age 8.9 years). A total of 67 different DDIs were counted (66 in Micromedex^® Solutions, 14 in G-Standard, and 13 DDIs in both databases). The medication reviews resulted in 35 interventions related to 11 different DDIs. The majority of DDIs concerned noncytostatic drugs (25/35) and one third occurred between cytostatic and noncytostatic drugs (10/35). The use of QTc-interval-prolonging drugs resulted in one intervention. The use of OTC drugs, CAM, or dietary supplements did not lead to DDIs.

CONCLUSIONS

This study resulted in a selection of 11 potentially clinically relevant DDIs for 73 outpatients in our pediatric oncology department. Interventions were formulated in close collaboration between physicians and clinical pharmacists. Future research should focus on assessing DDIs concerning QTc-interval prolongation.

Clinical pharmacokinetics of methotrexate in oncology

Methotrexate is an antifolate agent used in the treatment of autoimmune diseases and various types of cancers. It is a unique antiproliferative agent because it can be administered by multiple routes with a wide variation of dosing. Methotrexate pharmacokinetics have generated numerous papers focusing on descriptive data and pharmacodynamics. Methotrexate is one of the rare anticancer agents which pharmacokinetics are routinely monitoring to control excessive toxicity when administrated at high dose (>1 g/m2). The identification of transporters involved in its disposition has permitted the understanding and the prevention of most drug interactions. Pharmacogenetic factors affecting the expression of MRP2 and OATP1B1 partly explain the interindividual variability of methotrexate clearance. The remaining challenge in methotrexate pharmacokinetics is to further understand unexplained delayed renal elimination despite the implementation of preventive measures.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.