Methotrexate area under the curve as a prognostic factor in primary central nervous system lymphoma treated with immunochemoradiotherapy

Impact of Folinic Acid Dosing on Efficacy and Toxicity of High-Dose Methotrexate in Central Nervous System Lymphoma

INTRODUCTION

High-dose methotrexate (HDMTX)-based regimens are the treatment of choice in primary central nervous system lymphoma (PCNSL). Folinic acid (FA) rescue is used to mitigate the toxic effects of MTX on normal cells. However, the optimal dosing of FA in PCNSL remains uncertain.

METHODS

We analyzed the relationship between FA dosing and treatment efficacy and toxicity in a cohort of 36 PCNSL patients treated at our institute between the years 2014 and 2022. A combination of univariate and multivariate analyses using known prognostic factors were used to determine the association between FA dosing and treatment outcomes.

RESULTS

We found that higher per-treatment cumulative FA doses were associated with inferior progression-free survival (PFS), with a hazard ratio (HR) of 2.2 for each 100 mg/m2 increase in FA dose. We identified a threshold of 350 mg/m2/treatment, above which there was a significant reduction in PFS. Notably, lower FA doses did not result in increased toxicity.

CONCLUSION

Our findings suggest that optimizing FA dosing to avoid very high rescue doses may improve treatment outcomes in PCNSL patients receiving HDMTX. Further prospective studies are warranted to validate these findings.

Optimum Methotrexate Exposure in Patients With Suspected or Confirmed CNS Invasive Hematological Malignancies: A Systematic Critical Review

BACKGROUND AND METHODS

The present review aims to evaluate the current state-of-the-art dosing regimens of high-dose (HD) and intrathecal methotrexate (MTX) using therapeutic drug monitoring (TDM) to optimize its therapeutic response and minimize associated toxicity, particularly in the central nervous system (CNS).

RESULTS

MTX is administered systemically in a HD regimen (>1 g/m 2 ) for the treatment of various hematological neoplasms. HD-MTX treatment becomes complicated by marked interindividual drug elimination variability. TDM is specified to manage this high variability. Approximately 3%-7% of adults with acute lymphoblastic leukemia are diagnosed with CNS involvement, and the incidence of CNS relapse in patients, despite receiving prophylaxis, ranges from 5% to 10%. HD-MTX penetrates the blood-brain barrier and can be administered intrathecally, making this drug an important component of chemotherapy regimens for patients with hematologic malignancies involving the CNS or those at high risk of CNS relapse.

CONCLUSIONS

The major evidence found was that an MTX area under the curve target between 1000 and 1100 μmol hour -1 L is associated with better clinical outcomes. However, there seems to be a clinical gap in the prospective validation of HD and IT MTX management to optimize clinical outcomes and minimize toxicity, using the relationship between exposure level (area under the curve MTX) and optimal response to MTX, at systemic and CNS exposure.

Prospective evaluation of high-dose methotrexate pharmacokinetics in adult patients with lymphoma using novel determinants of kidney function

High-dose methotrexate (HDMTX) pharmacokinetics (PKs), including the best estimated glomerular filtration rate (eGFR) equation that reflects methotrexate (MTX) clearance, requires investigation. This prospective, observational, single-center study evaluated adult patients with lymphoma treated with HDMTX. Samples were collected at predefined time points up to 96 h postinfusion. MTX and 7-hydroxy-MTX PKs were estimated by standard noncompartmental analysis. Linear regression determined which serum creatinine- or cystatin C-based eGFR equation best predicted MTX clearance. The 80 included patients had a median (interquartile range [IQR]) age of 68.6 years (IQR 59.2-75.6), 54 (67.5%) were men, and 74 (92.5%) were White. The median (IQR) dose of MTX was 7.6 (IQR 4.8-11.3) grams. Median clearance was similar across three dosing levels at 4.5-5.6 L/h and was consistent with linear PKs. Liver function, weight, age, sex, concomitant chemotherapy, and number of previous MTX doses did not impact clearance. MTX area under the curve (AUC) values varied over a fourfold range and appeared to increase in proportion to the dose. The eGFR_cys (ml/min) equation most closely correlated with MTX clearance in both the entire cohort and after excluding outlier MTX clearance values (r = 0.31 and 0.51, respectively). HDMTX as a 4-h infusion displays high interpatient pharmacokinetic variability. Population PK modeling to optimize MTX AUC attainment requires further evaluation. The cystatin C-based eGFR equation most closely estimated MTX clearance and should be investigated for dosing and monitoring in adults requiring MTX as part of lymphoma management.

Primary CNS lymphoma

Primary diffuse large B-cell lymphoma (DLBCL) of the central nervous system is an aggressive malignancy that exhibits unique biological features and characteristic clinical behaviour, with overall long-term survival rates of around 20–40 %. Clinical outcome has improved following the advent of chemoradiation protocols incorporating high-dose methotrexate in the mid-1980s, but disease relapse and adverse neurocognitive sequelae remain major clinical challenges. To address this, investigators have focused on improving drug therapy with novel cytotoxic combinations, monoclonal antibody therapy, and intensive chemotherapy consolidation approaches, in an attempt to improve disease control whilst reducing the requirement for whole-brain radiotherapy. Outcomes for patients that are older, immunocompromised, or have relapsed/refractory disease remain unsatisfactory and there is a paucity of clinical trial data to guide treatment of these groups. This review highlights recent advances in pathobiology, imaging, and clinical management of PCNSL and looks ahead to research priorities for this rare and challenging lymphoid malignancy.

Methotrexate re-challenge for recurrent primary central nervous system lymphoma

The prognosis of primary CNS lymphoma (PCNSL) recurring after methotrexate is poor (objective response rates [ORR] = 26-53 %; 1-year overall survival [OS] = 35-57 %). Salvage PCNSL chemotherapies have been based on the use of different agents to avoid cross-resistance; however, methotrexate is the most active agent in PCNSL, and methotrexate re-challenge may be an effective strategy for recurrent disease. We report our experience with methotrexate re-challenge in PCNSL. We reviewed 39 patients with histologically confirmed PCNSL who responded to methotrexate at initial diagnosis, experienced disease relapse and received methotrexate re-challenge. At the time of re-challenge, median age was 66 and median Karnofsky performance score (KPS) was 70. Median time from initial diagnosis was 26 m. Twenty-six patients were at first relapse and 13 at second or later relapse. At re-challenge, methotrexate was given in combination with other agents to 33 patients and as a single agent to six. The objective response rate was 85 %, with a complete response in 29 (75 %) patients, partial response in four (10 %) and disease progression in six (15 %). At median follow-up of 26 m, the median progression-free survival was 16 m; 1-year OS was 79 % (95 % CI 63-89) and median OS was 41 m. KPS was a prognostic factor for progression free survival (p = 0.04). In this population selected by previous methotrexate response, methotrexate re-challenge was a safe and effective strategy, indicating chemosensitivity was retained. Efficacy compared favorably to other salvage treatments suggesting methotrexate re-challenge should be considered in recurrent PCNSL patients who previously responded to methotrexate.

Rituximab, methotrexate, procarbazine, and vincristine followed by consolidation reduced-dose whole-brain radiotherapy and cytarabine in newly diagnosed primary CNS lymphoma: final results and long-term outcome

PURPOSE

A multicenter phase II study was conducted to assess the efficacy of rituximab, methotrexate, procarbazine, and vincristine (R-MPV) followed by consolidation reduced-dose whole-brain radiotherapy (rdWBRT) and cytarabine in primary CNS lymphoma.

PATIENTS AND METHODS

Patients received induction chemotherapy with R-MPV (five to seven cycles); those achieving a complete response (CR) received rdWBRT (23.4 Gy), and otherwise, standard WBRT was offered (45 Gy). Consolidation cytarabine was given after the radiotherapy. The primary end point was 2-year progression-free survival (PFS) in patients receiving rdWBRT. Exploratory end points included prospective neuropsychological evaluation, analysis of magnetic resonance imaging (MRI) white matter changes using the Fazekas scale, and evaluation of the apparent diffusion coefficient (ADC) as a prognostic factor.

RESULTS

Fifty-two patients were enrolled, with median age of 60 years (range, 30 to 79 years) and median Karnofsky performance score of 70 (range, 50 to 100). Thirty-one patients (60%) achieved a CR after R-MPV and received rdWBRT. The 2-year PFS for this group was 77%; median PFS was 7.7 years. Median overall survival (OS) was not reached (median follow-up for survivors, 5.9 years); 3-year OS was 87%. The overall (N = 52) median PFS was 3.3 years, and median OS was 6.6 years. Cognitive assessment showed improvement in executive function (P < .01) and verbal memory (P < .05) after chemotherapy, and follow-up scores remained relatively stable across the various domains (n = 12). All examined MRIs (n = 28) displayed a Fazekas score of ≤ 3, and no patient developed scores of 4 to 5; differences in ADC values did not predict response (P = .15), PFS (P = .27), or OS (P = .33).

CONCLUSION

R-MPV combined with consolidation rdWBRT and cytarabine is associated with high response rates, long-term disease control, and minimal neurotoxicity.

Primary CNS lymphoma: a clinician's guide

Primary CNS lymphoma is a high malignant disease of the brain which can lead rapidly to death if diagnosis and/or the start of treatment is delayed. The age at time of diagnosis is a strong factor influencing prognosis so that in younger patients <65 years of age long-term survival may be achieved in a substantial percentage of patients, while in elderly patients long-term survival is seen much more rarely. First-line therapy consists of high-dose methotrexate-based (poly)chemotherapy. This review provides an overview of clinical presentation, steps to diagnosis, detailed information about current treatment concepts and specific information for particular clinical situations.

Rational administration schedule for high-dose methotrexate in patients with primary central nervous system lymphoma

Methotrexate (MTX) at a dose of ≥1 g/m(2) remains the most efficient treatment against primary central nervous system lymphoma (PCNSL), and is the most widely used drug in prospective clinical trials. MTX is a folate analog that inhibits dihydrofolate reductase, thereby blocking de novo purine synthesis. MTX as well as 7-hydroxy-MTX, its main metabolite in serum, are both eliminated by the kidneys. The elimination of MTX is prolonged in patients with renal impairment and third-space fluid collections, and in patients receiving concurrent non-steroidal antirheumatic drugs, benzimidazoles and sulfonamides, among others. Main adverse events with high-dose MTX include severe myelosuppression, renal dysfunction and stomatitis. Supportive measures such as rigorous hydration, urine alkalinization and careful drug monitoring with supplemental leucovorin rescue are crucial to avoid significant toxicity. Strategies to optimize clinical efficacy of high-dose MTX in patients with PCNSL include administration of 3 h instead of longer infusions, potentially supplemented with an additional intravenous MTX bolus, and maintaining MTX dose intensity over the course of four treatment cycles. Some pharmacological studies suggest that achieving an MTX area under the plasma concentration-time curve (AUC(MTX)) of between 1000 and 1100 μmol.h/L may improve clinical outcome, but clinical data are not conclusive at present. In this review, we analyze the impact of patient, lymphoma and pharmacokinetic variables on the antitumor activity of high-dose MTX in patients with PCNSL, summarize recommendations for daily clinical practice and give some suggestions for future trials.

The prognostic value of serum methotrexate area under curve in elderly primary CNS lymphoma patients

Studies on pharmacokinetics and pharmacodynamics of high-dose methotrexate chemotherapy (HD-MTX) in elderly primary central nervous system lymphoma (PCNSL) patients are rare. MTX exposure time has recently been proposed as an outcome determining factor in PCNSL. We investigated 49 immunocompetent PCNSL patients (female N=30, male N=19, median age 73 years) who were treated according to HD-MTX-based protocols. A two-compartment pharmacokinetic model was used to describe the MTX clearance. Response to treatment was assessed by MRI. We used multivariable models to investigate the association between MTX exposure and tumor response as well as survival. Dose normalized MTX peak serum levels [C (max), μmol/L g] and dose normalized area under the curve [AUC(dn), μmol h/L g] were higher in females than in males, respectively [59.4 (f) vs. 48.1 (m), P<0.001; 373.2 (f) vs. 271.9 (m), P=0.008]. Increasing AUC was inversely correlated with tumor response. AUC values above 2,126 h μmol/L were independently associated with shorter overall and progression-free survival [hazard ratio (HR), 4.56, 95 % CI 1.74-11.94; HR 2.87, 95 % CI 1.18-7.00]. Exceedingly high MTX AUC levels can have a negative impact on progression-free and overall survivals in elderly PCNSL patients.