High-dose Methotrexate In Patients Research Articles

High-Dose Methotrexate in Patients With Lymphoma: Predictors of a Complicated Course.

High-dose methotrexate (HDMTX; > 500 mg/m2) is an important component of lymphoma therapy. Serum MTX monitoring at 48 hours is the standard approach to identify those at increased risk of developing MTX toxicity. Our aim was to characterize the incidence of complications and their association with MTX levels. A retrospective review of our institutional electronic medical record was conducted to identify patients with lymphoma who received HDMTX between January 1, 2002, and December 31, 2018. We characterized the incidence of acute kidney injury (AKI), intensive care unit (ICU) admission, length of hospital stay (LOS), and 30-day mortality across 48-hour MTX levels. To establish an association between 48-hour MTX levels and the complications listed, we performed chi-square analysis for dichotomous variables and Kruskal-Wallis for nonparametric data. Receiver operator characteristic curve analysis was performed to identify the MTX level where AKI grade ≥ 2 was more likely. Multivariate logistic regression analysis was performed to identify risk factors for this MTX level. We identified 642 patients with 2,804 cycles of HDMTX. The incidence of AKI was 19.1% with AKI grade ≥ 2 making up 21% of cases. Rates of AKI, ICU admission, and 30-day mortality are associated with elevated 48-hour MTX levels. There was a significant increase in median LOS with elevated MTX levels (P < .001). Receiver operator characteristic curve analysis for AKI grade ≥ 2 demonstrated a 48-hour MTX level threshold of 1.28 μmol/L. Multivariate logistic regression analysis revealed age, male sex, elevated body surface area, higher MTX dose, monotherapy, and first cycle as independent factors. Elevated MTX levels are associated with a significant increased rate of AKI, ICU admission, prolonged LOS, and 30-day mortality. Elevated 48-hour MTX levels, particularly > 1.28 μmol/L, should alert clinicians for complications and to initiate measures to reduce MTX levels.

Safety analysis of high-dose methotrexate in pediatric non-Hodgkin lymphomas.

High-dose methotrexate (HD-MTX) with rigorous supportive care is essential to the treatment of pediatric non-Hodgkin lymphomas (NHL). We describe the safety and tolerability of HD-MTX in patients with NHL treated at our center. In our cohort of 46 patients, the majority had at least one course of delayed clearance and/or creatinine elevation. Additionally, more than one-third of patients experienced an episode of grade ≥3 mucositis. Creatinine elevations and delayed clearance were independently associated with subsequent grade ≥3 mucositis. We advocate for greater availability of methotrexate monitoring to allow dose escalation of this essential modality around the world.

Urine volume to hydration volume ratio is associated with pharmacokinetics of high-dose methotrexate in patients with primary central nervous system lymphoma.

High‐dose methotrexate (HD‐MTX)‐based chemotherapy is the first‐line treatment for primary central nervous system lymphoma (PCNSL), but is associated with severe adverse effects, including myelosuppression and renal impairment. MTX is primarily excreted by the kidneys. Renal function calculated using serum creatinine (Scr) derived from muscle may be overestimated in elderly PCNSL patients. Therefore, we aimed to construct a population pharmacokinetic model in PCNSL patients and explore the factors associated with MTX clearance. Sixteen PCNSL patients (median age, 66 years) treated with HD‐MTX were included, and serum MTX concentrations were measured at 193 points in 49 courses. A population pharmacokinetic analysis was performed using NONMEM. A Monte Carlo simulation was conducted, in which serum MTX concentrations were stratified into three groups of creatine clearance (Ccr) (50, 75, and 100 ml/min) with three groups of the urine volume to hydration volume (UV/HV) ratio (<1, 1–2, and >2). The final model was constructed as follows: MTX clearance = 4.90·(Ccr/94.5)0.456·(UV/HV)0.458. In the Monte Carlo simulation, serum MTX concentrations were below the standard values (10, 1, and 0.1 µM at 24, 48, and 72 h, respectively, after the start of the MTX administration) in most patients with UV/HV >2, even with Ccr of 50 ml/min. Conversely, half of the patients with UV/HV <1 and Ccr of 50 ml/min failed to achieve the standard values. The present results demonstrated that the UV/HV ratio was useful for describing the pharmacokinetics of MTX in PCNSL patients.

Evaluation of Risk Factors and Survival Effect of Delayed Excretion of High-Dose Methotrexate in Patients with Leukemia and Lymphoma

▪Background: High-dose methotrexate (HD-MTX) with or without other drugs is a common regimen for treating and preventing central nervous system involvement in patients with leukemia and lymphoma. Despite leucovorin rescue combined with appropriate hydration and urine alkalinization, some patients still have delayed MTX excretion. While avoiding HD-MTX in patients with several prior known risk factors such as pre-existing renal dysfunction, third space fluid collection, and co-administration of nephrotoxic agents, delayed MTX excretion remains a risk factor for serious adverse effects that may cause treatment cessation, serious organ damage, and death. This study aimed to identify risk factors of HD-MTX by examining clinical and laboratory characteristics of patients with and without delayed MTX excretion and understand prognostic effects of delayed MTX excretion.Method: We included patients with leukemia or lymphoma who received HD-MTX at Kameda Medical Center, Japan between September 2011 and April 2017. The primary and secondary end points were risk factors associated with delayed MTX excretion and evaluation of the relationship between delayed MTX excretion and survival, respectively. Patients received adequate hydration and alkalinization to maintain urine pH > 7.0, leucovorin rescue, and other supportive care based on institutional guidelines. Delayed MTX excretion was defined as plasma MTX levels ≥ 1 μmol/L at 48 h or ≥ 0.1 μmol/L 72 h after HD-MTX commenced. Risk factors contributing to delayed MTX excretion were identified using univariate and multivariate analyses, and overall survival (OS) was estimated using the Kaplan-Meier method. This study conformed to the principles of the Declaration of Helsinki.Result: We identified 120 patients (16 to 84 yr) who received HD-MTX during the study (mean, 2.24 g/m2, 95%CI:2.13-2.36) administered in 318 cycles (median, 2 cycles; range, 1-12 cycles/patient) with or without chemotherapy. Delayed MTX excretion occurred in 70 cycles (22.0%), 23 at 48 h and 49 at 72 h, and 2 in both, in 51 (42.5%) patients. The demographic baseline patient characteristics showed that delayed MTX excretion occurred more frequently in aged (median, 70 yr; range, 35-84 yr vs 64 yr; range, 16-80 yr, p < 0.006) and male (70.6 vs 53.6%, p = 0.008) patients than in other patients. Delayed MTX excretion occurred more frequently in patients receiving therapy than in those on prophylaxis (25 [49.0%] vs 9 [13.0%] patients, p < 0.01). The disease category proportion (leukemia or lymphoma) and chemotherapy protocol did not differ between groups.The risk factors were analyzed by comparing the 248 and 70 cycles of not delayed and delayed MTX excretion, respectively. Risk factors analyzed in this study were age > 65 yr, male sex, serum albumin< 3 g/dL, body mass index > 25 kg/m2, creatinine clearance (CCr) < 60 mL/min, MTX dose > 3 g/m2, urine pH < 7.0 during treatment, ascites, pleural fluid, and co-administration of interactive agents for MTX excretion (NSAIDs, PPI, sulfamethoxazole-trimethoprim, or furosemide), which were considered risk factors for delayed MTX excretion.Univariate analysis showed that delayed MTX excretion was associated with age > 65 yr (75.7 vs 51.1% in the delayed vs not delayed cohorts, p = 0.002), male sex (74.2 vs 51.1%, p = 0.02), serum albumin < 3 g/dL (25.7 vs 11.1%, p = 0.007), CCr < 60 mL/min (30.0 vs 13.0%, p = 0.003), urine pH < 7.0 during treatment (28.5 vs 7.4%, p < 0.01), presence of pleural fluid (5.7 vs 0.7%, p = 0.02). In the multivariate analysis, male sex [odds ratio (OR) 2.07, 95% confidence interval (CI): 1.09-3.92, p < 0.01], CCr < 60 mL/min (OR 3.57, 95% CI: 1.84-6.95, p < 0.01), urine pH during treatment < 7.0 (OR 4.97, 95% CI: 2.39-10.3, p < 0.01), and presence of pleural effusion (OR 10.6, 95% CI: 1.6-70.6, p < 0.01) were identified as an independent risk factor of delayed MTX excretion.Patients with delayed MTX excretion had higher nephrotoxicity incidences than those without delayed excretion did (23.5 vs 4.3%, p = 0.003). In the survival analysis, patients with delayed MTX excretion had shorter OS than those without delayed excretion did [n = 51, median OS: 47 months, 95% CI: 19-99 vs n = 69 median OS: not reached (NR), 95% CI: 52-NR].Conclusion: To the best of our knowledge, this is the first study to identify clinical risk factors associated with delayed MTX excretion in patients on HD-MTX. We also showed that delayed MTX excretion was associated with poor OS. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Lack of drug interaction between levetiracetam and high-dose methotrexate in patients with lymphoma.

To determine whether there is a drug-drug interaction precluding the concomitant use of levetiracetam and high-dose methotrexate (HDMTX). Retrospective analysis. Large academic tertiary care medical center. Adult lymphoma patients who received HDMTX as a 4-h infusion with or without concomitant levetiracetam. Generalized estimating equations clustered on patient were used to assess each outcome. The primary outcome was the incidence of delayed MTX elimination (MTX level >1 µmol/L at 48 h). Secondary outcomes included incidence of acute kidney injury (AKI) and hospital length of stay (LOS). The 430 included patients receiving 1993 doses of HDMTX had a median (IQR) age of 66 (57.5, 72.6) years, 88 (20.5%) received concomitant levetiracetam with at least one dose of MTX, 267 (62.1%) were male, and 397 (92.3%) were Caucasian. HDMTX doses ranged from 1 to 8 g/m2 . The most common lymphoma diagnoses were systemic diffuse large B-cell lymphoma (DLBCL; 58.5%) and systemic DLBCL with central nervous system (CNS) involvement (32.8%). Rates of delayed elimination with and without levetiracetam were 13.4% and 16.3%, respectively (OR = 0.80, 95% CI 0.47-1.34, p = 0.39). AKI occurred in 15.6% and 17.0% of patients with and without concomitant levetiracetam, respectively (OR = 0.83, 95% CI 0.52-1.33, p = 0.28). The median LOS with and without levetiracetam was 4.2 and 4.1 days, respectively (p = 0.039). On multivariable analyses, only age, body surface area, diagnosis of systemic DLBCL with CNS involvement, serum creatinine, hemoglobin, total bilirubin, and dose of HDMTX were associated with delayed elimination. High-dose methotrexate administered with concomitant levetiracetam was not associated with increased risk for delayed MTX elimination or AKI. These results support that levetiracetam and HDMTX are safe for coadministration.

Low Serum Albumin Level Is a Risk Factor for Delayed Methotrexate Elimination in High-Dose Methotrexate Treatment.

In high-dose methotrexate (HD-MTX) therapy, delayed elimination of MTX from plasma leads to severe adverse effects. However, the risk factors for the delayed elimination of plasma MTX are still unclear. The purpose of this study was to investigate the factors related to the delayed MTX elimination in HD-MTX monotherapy. This retrospective study was performed on patients who received HD-MTX monotherapy between April 2009 and March 2019 at the Hiroshima University Hospital. Patients were divided into a "Normal" and a "Delayed" group according to their MTX plasma concentration at 48 or 72 hours after administration. Patient characteristics, dose of HD-MTX, MTX plasma concentration, and adverse effects were analyzed and compared between the 2 groups. A total of 74 patients were included in this study. Logistic analysis of patient baseline characteristics was performed to identify risk factors for delayed MTX elimination. Serum albumin (ALB) was detected as a risk factor. Univariate and multivariate analysis revealed that low ALB level (<3.7 g/dL) and type of cancer were associated with delayed MTX elimination (univariate analysis: odds ratio [OR] = 6.00, P = 0.004, and OR = 4.33, P = 0.039, respectively; multivariate analysis: adjusted OR [AOR] = 6.45, P = 0.006, and AOR = 8.11, P = 0.018, respectively). Adverse effects were not significantly different between the 2 groups, excluding renal impairment. Our study showed that low ALB is a risk factor for delayed MTX elimination in HD-MTX monotherapy. Pharmacokinetic analysis is needed to establish the dose of HD-MTX in patients with a low ALB level.

Coadministration of vindesine with high-dose methotrexate therapy increases acute kidney injury via BCRP, MRP2, and OAT1/OAT3

To investigate whether coadministration of vindesine is a risk factor for acute kidney injury caused by high-dose methotrexate in patients with hematologic malignancies and identify its mechanism. A retrospective analysis was conducted on 211 cycles of HD-MTX therapy in 178 patients with hematological malignancies. Multivariate logistic regression analysis was performed to evaluate whether VDS coadministration was a risk factor for AKI and the inhibitory effect of VDS on MTX was studied in cell models in vitro. The occurrence of AKI was significantly higher in the MTX + VDS group than in the MTX group. Multivariate logistic regression analysis showed that VDS coadministration was an important risk factor for the occurrence of AKI [odds ratio (OR) = 2.62, 95% confidence interval (CI) 1.03-6.66]. After coadministration of VDS, serum MTX concentrations at 24h, 48h, and 72h increased from 0.42 ± 0.46μmol/L, 0.07 ± 0.01μmol/L, and 0.03 ± 0.01μmol/L to 0.98 ± 2.73μmol/L, 0.18 ± 0.42μmol/L, and 0.09 ± 0.21μmol/L (p < 0.05, p < 0.01, and p < 0.01), respectively. Delayed elimination was closely related to AKI (p < 0.001). The transfected cell model results showed that VDS is an inhibitor of the transporters BCRP, MRP2, and OAT1/OAT3. VDS inhibited BCRP and MRP2-mediated transport of MTX with IC50 values of 17.91µM and 34.73µM, respectively. Coadministration of VDS increases HD-MTX-induced AKI in patients with hematologic malignancies, which may be explained by the fact that VDS increases the exposure to and decreases the excretion of MTX by inhibiting OAT1/OAT3, BCRP, and MRP2.

Systemic high-dose intravenous methotrexate in patients with central nervous system metastatic breast cancer

BackgroundInfusion of high-dose intravenous methotrexate (MTX) has been demonstrating to penetrate the blood-brain barrier. The aim of this present study was to assess the efficacy and safety of high dose MTX in patients with central nervous system (CNS) metastases of breast cancer.MethodsTwenty-two patients with CNS metastases treated by MTX (3 g/m2) between April 2004 and October 2009 were enrolled. Clinical response rate, time to progression (TTP), overall survival (OS), and safety were assessed.ResultsIn terms of brain metastases, 2 patients (9%) achieved a partial response, 10 patients (45%) had disease stabilization, and 10 patients (45%) had disease progression. In others metastatic sites, 7 patients (39%) achieved a disease stabilization, and 11 patients (61%) had disease progression. TTP and OS were 2.1 (95%CI 1.4–2.9) and 6.3 (95%CI 1.8–10) months, respectively.ConclusionHigh-dose MTX demonstrated a moderate activity at 3 g/m2. Nonetheless, the favorable toxicity profile should suggest the possibility to increase the dosage and further study are planned.

Limited efficacy of high-dose methotrexate in patients with neurolymphomatosis

Neurolymphomatosis (NL) is a rare manifestation of non-Hodgkin lymphoma, in which malignant cells infiltrate the peripheral nerves. Most patients are treated with high-dose methotrexate (HD-MTX)-based systemic chemotherapy regimens similar to patients with central nervous system lymphoma. However, because NL is rare, the efficacy of HD-MTX is largely unknown. We reviewed medical records of patients diagnosed with NL over the past 10years and identified 18 patients. The underlying hematological malignancy was diffuse large B-cell lymphoma (DLBCL) in 10 patients (55.6%), intravascular large B-cell lymphoma in six (33.3%), and other types in two patients. Ten patients were treated with HD-MTX-based systemic chemotherapy; the response rates with and without HD-MTX-based chemotherapy were 100% (n = 10) and 85.7% (n = 6), respectively (P = 0.41). The median progression-free and overall survival rates of patients with versus without HD-MTX treatment were 6.4 vs. 8.5months (P = 0.97) and 13.5 vs. 8.5months (P = 0.63), respectively. Despite the initial favorable responses, rapid disease recurrence was observed in most patients administered HD-MTX-based chemotherapy. Our observations suggest that HD-MTX-based chemotherapy may have insufficient efficacy against NL, and that other therapeutic approaches are required to improve the outcomes of patients with this rare disease.

Prophylaxis with Intrathecal Chemotherapy and High Dose Methotrexate in Patients with Diffuse Large B Cell Lymphoma at High Risk for Central Nervous System Relapse: A Single Centre Experience

Central nervous system involvement (CNS) is a serious and mostly fatal complication of aggressive lymphoma. The incidence of CNS disease in diffuse large B-cell lymphoma (DLBCL) is low (about 5%) and there are not randomised prospective trial which specifically address a decision-making process for CNS prophylaxis. Potentially two methods exist for identifying patients requiring CNS directed treatment. Surveillance lumbar puncture and brain magnetic resonance (MRI) at the time of diagnosis could identify the presence of lymphoma; another method is the identification of patients whose characteristics are indicative of a high risk of CNS disease. Several site-specific risks are described in literature such as testicular, breast, paranasal sinuses, epidural spaces, and intravascular involvement with an incidence of CNS relapse ranging from 15% to 50%. Recently a modified IPI score (CNS IPI) was described to predict risk of CNS relapse.The efficacy of different forms of CNS prophylaxis has never formally been demonstrated. In the RICOVER 60 trial, patients treated with R-CHOP-14 instead of CHOP-14 presented a lower incidence of CNS relapse while intrathecal methotrexate (MTX) has not showed a role in preventing CNS disease for patients treated with combined immunochemotherapy. Recently, combination of intrathecal MTX and high dose MTX infusion after R-CHOP treatment was considered an effective strategy of prevention of CNS relapse.In order to evaluate the efficacy and feasibility of intrathecal MTX administration and high dose MTX after first line chemotherapy, we retrospectively reviewed 27 patients (11 males and 16 females, mean age 61 yrs, range 27-79) with newly diagnosed DLBCL at high risk for CNS relapse, treated from January 2009 to April 2018 at Veneto Institute of Oncology IOV-IRCCS.In our cohort 21 (78%) patients were at advanced stage (III-IV Ann Arbor stage) and 15 (56%) belonged to intermediate-high or high risk IPI categories, two patients presented with orbital localization. Almost all patients received R-CHOP as first line treatments, two patients with paravertebral localization received HyperCVAD as front line approach.For 20 patients CNS-IPI was intermediate or high. In the other cases with low CNS-IPI, disease localization was considered at high risk of CNS relapse (breast, paravertebral, orbit, paranasal sinus). In all patients we performed brain MRI and diagnostic lumbar puncture at diagnosis (all negative at flow cytometry analysis). All 14 patients >65 yrs were evaluated with comprehensive geriatric assessment (CGA) and 8 (57%) were considered fit.Nineteen (19) patients (70%) received at least 3 lumbar punctures with MTX and 24 (89%) two courses of high dose intravenous MTX during first line therapy.At the end of planned first line treatment, 24 (89%) patients obtained a complete remission at PET scan evaluation and 3 patients (11%) presented progressive disease, 2 with CNS involvement and another with peritoneal disease; this last patient had a Double Hit lymphoma with BCL6 and c-MYC rearrangements. Another patient in complete remission after R-CHOP chemotherapy, experienced CNS relapse three year after obtaining complete remission. Among the two patients treated with Hyper CVAD regimen, one is still in complete remission 5 years after the end of treatment; another developed early CNS relapse.All the 3 patient who experienced CNS involvement after R-CHOP, didn't receive prophylaxis because were evaluated frail at CGA. So, at a median follow up of 26.2 months (3.5-100 months) all patients who received the planned treatment at full dose including CNS prophylaxis did not experience central nervous system relapse.In conclusion, CNS prophylaxis including intrathecal MTX administration and high dose MTX infusion after first line chemotherapy is feasible and effective.Larger prospective trials are needed to evaluate the most effective prophylactic therapy and the correct timing of intravenous MTX infusion. DisclosuresNo relevant conflicts of interest to declare.

Evaluation, Identification, and Management of Acute Methotrexate Toxicity in High-dose Methotrexate Administration in Hematologic Malignancies.

The pharmacological and medical management of complex chemotherapy regimens are vast and complex, requiring an intimate understanding of physiology, particularly when novel biologic agents are utilized with commonly used regimens. The molecular classification in patients with diffuse large B-cell lymphoma (DLBCL) is multifaceted, particularly with the expansion of novel molecular targets. The pharmacological and medical management of hematologic malignancies with a tendency to have central nervous system (CNS) involvement is complex and requires an understanding of physiology and pharmacology. Many chemotherapy regimens used to treat hematologic malignancies with either CNS involvement or high risk for CNS disease will include the administration of high dose methotrexate. This requires having physiological understanding with respect to the standard regimens for DLBCL in addition to understanding cytogenetic markers, such as c-myc and bcl-2, the expression of which displays increased likelihood of CNS involvement. In patients with documented CNS disease and active neurological manifestations such as myclonus, headaches, nystagmus, and blurred vision, the utilization of high dose methotrexate has become an essential standard of care. We examine the pharmacologic mechanisms of high dose methotrexate in patients with hematologic malignancies such as DLBCL and review the most common toxicities on a multidisciplinary level.

Predictors of Delayed Clearance and Toxicities from High Dose Methotrexate in Patients Receiving Hypercvad Regimen for Treatment of Lymphoid Malignancies

Introduction: High dose Methotrexate (HDMTX) has been the backbone of chemotherapeutic regimens used for the treatment of lymphoid malignancies. Altered disposition of MTX may result in increased systemic exposure accompanied by severe adverse effects and organ toxicities. Diversity in toxicity profile has been shown to be associated with various clinical factors as well as genetic polymorphisms. In particular, single nucleotide polymorphisms (SNPs) in the solute carrier organic anion transporter 1B1 (SLCO1B1) gene especially rs4149056 and rs2306283 had been previously reported to be significantly associated with MTX concentration at 24 hours post-infusion, MTX AUC from 0-48 hours, MTX clearance and toxicities in the Caucasian pediatric population.Aim: This study aimed to characterize clearance and toxicity profile [in particular acute kidney injury (AKI) and hepatotoxicity]; and identify clinical and genetic covariates associated with clearance and toxicities of HDMTX in patients receiving HyperCVAD-B regimen for treatment of lymphoid malignancies in the local setting.Methods: This single-centered, retrospective study included all treatment-naïve patients of Asian descent who received HDMTX as part of the HyperCVAD-B regimen for treatment of lymphoid malignancies from January 2008 to December 2015 in Department of Hematology, Singapore General Hospital. Pertinent clinical data including baseline demographics, disease characteristics, treatment details, plasma MTX levels, and treatment outcomes were extracted from case notes and electronic records onto a standardized data collection form. Association between toxicities parameters and MTX levels were analyzed. Genotyping for two SNPs in the SLCO1B1 gene namely, rs2306283 and rs4146056 was using blood samples obtained from the Hematology Department Tissue Repository. Primary endpoint was incidence of delayed clearance and toxicities of HDMTX in the study population. Secondary endpoints included clinical factors and genetic covariates associated with reduced MTX clearance and toxicities.Results: A total of 102 patients (215 treatment cycles) were included, with each patient receiving median of 2 cycles (range, 1 to 6). Median age was 45 years (range, 18 - 69), and 58 (56.9%) were male. Eighty-seven patients were diagnosed with acute lymphoblastic leukemia (ALL), whereas 12 patients had lymphoma. Sixty-one patients (59.8%) were found to have at least 1 episode of delayed clearance, occurring in 89 (41.4%) treatment cycles. Median time to MTX clearance was significantly longer in patients with delayed clearance at 69.8 hours (range, 4.5-277.2) as compared to 41 hours (range, 0 - 86.3 hours), p<0.001. Approximately 25% and 47% of the patients developed AKI and hepatotoxicity attributable to MTX, respectively. A significant association between delayed clearance and occurrence of AKI was observed, with 24% of patients with delayed clearance developing AKI vs 2% in those without delayed clearance, p<0.001. Number of treatment cycles [odds ratio (OR) = 2, 95% confidence interval (CI) 1.3 - 3.1, p = 0.002]; and age ≥ 40 (OR 3.7, 95% CI 1.4 - 9.6, p = 0.008) were found to be associated with delayed clearance. Occurrence of delayed clearance (OR = 29, 95% CI = 3.7 - 228, p = 0.001), and baseline hepatic impairment (OR = 9.5, 95% CI = 2 - 45, p = 0.005) were found to predict for AKI and hepatotoxicity, respectively. Genotyping for SLCO1B1 rs2306283 and rs4146056 was carried out for 39 patients with samples available in the repository. Frequencies and outcomes were shown in Table 1 and Table 2, respectively. Due to the small sample size, no definitive correlations between specific genotypes and clearance and outcomes could be elucidated.Conclusion: Delayed clearance of HDMTX occurred in a substantial proportion of patients at approximately 60%, which was in turn associated with occurrence of AKI. Risk of delayed clearance seemed to increase with age (≥ 40) and number of treatment cycles. This underscores the need for more effective strategies to facilitate clearance of HDMTX especially in patients with identified risk factors. Larger sample size would be essential to determine associations between genotypes and clearance and toxicities. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Hypoalbuminemia is significantly associated with increased clearance time of high dose methotrexate in patients being treated for lymphoma or leukemia.

As a weak acid, methotrexate (MTX) is bound to serum albumin and has variable protein binding. The purpose of this study was to assess serum albumin's relationship with MTX pharmacokinetics by comparing MTX clearance and toxicities between patients with normal serum albumin to those with hypoalbuminemia. This single-center retrospective study included adult patients with leukemia or lymphoma who received their first MTX at a dose ≥1g/m2. Hypoalbuminemia was defined as serum albumin ≤3.4g/dL. MTX clearance was defined as the first documented time the MTX level ≤0.05μM. Fisher's exact tests and Wilcoxon rank sum tests were used to examine differences in toxicities, and Cox proportional hazard regression was used to assess relationship with time to clearance. Of 523 patients identified, 167 patients were evaluable. One hundred thirty-five patients had normal serum albumin and 32 had hypoalbuminemia. Hypoalbuminemia was associated with a higher proportion of patients experiencing edema, ascites or pleural effusions (34 vs. 12%, p = 0.006), and the concomitant use of nephrotoxic agents (41 vs. 20%, p = 0.021). Hypoalbuminemia was associated with a significantly longer time to MTX clearance (median 96 vs. 72h, p = 0.004). In addition, patients with hypoalbuminemia had a higher proportion of hyperbilirubinemia and significantly longer hospitalization (median 14 vs. 5days, p < 0.001). In conclusion, hypoalbuminemia was associated with increased time to MTX clearance and increased length of hospitalization. High dose MTX is safe to administer in patients with low albumin levels, with appropriate leucovorin rescue, and good supportive care.

Hypoalbuminemia Is Significantly Associated with Increased Clearance Time of High Doses of Methotrexate

Introduction: Methotrexate is an antimetabolite chemotherapeutic agent used for over 50 years. The inclusion of high dose methotrexate with leucovorin rescue has enhanced lymphoma and acute leukemia regimens' efficacy. As a weak acid, methotrexate has variable protein binding and about 50% of the drug binds to serum albumin. Animal models suggest that methotrexate conjugated to albumin may improve anti-tumor effects by accumulating in tumor cells through endocytosis, decreasing its clearance. Further, greater methotrexate toxicity has been reported in patients with hypoalbuminemia. Our purpose was to assess serum albumin's impact on methotrexate pharmacokinetics by comparing methotrexate clearance and toxicities between patients with normal serum albumin and hypoalbuminemia.Methods: This IRB approved single-center retrospective study at Memorial Sloan Kettering Cancer Center included patients who were ≥18 years of age, received methotrexate at a dose of ≥1 gram/m2 between January 2007- November 2014, and admitted to the inpatient leukemia or lymphoma service. Patients admitted to other services or who had prior methotrexate exposure were excluded. Patients were identified through the pharmacy database and electronic medical records. Patients were categorized based on their most recent serum albumin level prior to methotrexate administration. Hypoalbuminemia was defined as serum albumin ≤ 3.4 g/dL. The relationship between hypoalbuminemia and clinical variables was assessed with Fisher's exact and Wilcoxon Rank Sum tests. Kaplan Meier methods were used to visualize the relationship between hypoalbuminemia with time to methotrexate clearance. Methotrexate clearance was defined as the first documented time the methotrexate level ≤0.05 micromolar. Univariate and multivariate associations between predictors and clearance were assessed with Cox proportional hazards regression. Clinical variables considered for the Cox model included hypoalbuminemia, urine acidity, renal function, fluid retention, presence of drug interactions, methotrexate dose, and nephrotoxic agents. Any variables significant at p<0.05 were considered for multivariate analysis.Results: Of 523 patients identified, 167 patients were evaluable. Of them 126 had lymphoma (75.4%) and 41 patients had leukemia (24.6%). The most common chemotherapy regimens used were R-CODOX/M-IVAC (21%), pediatric inspired acute lymphoblastic leukemia regimens (15%), HyperCVAD (12%), SMILE (11.4%), and MR-CHOP (10%). 135 patients had normal serum albumin and 32 had hypoalbuminemia. Baseline characteristics were similar between cohorts. Hypoalbuminemia was associated with a higher proportion of patients with fluid retention (34% vs. 12%, p=0.006) and concomitant use of nephrotoxic agents (41% vs. 20%, p=0.02). Hypoalbuminemia was associated with a significantly longer time to methotrexate clearance (median: 96 hours, 95% CI: 72-132 hours) vs normal serum patients (median 72 hours, 95% CI: 63-72 hours), p=0.004) (Figure 1). In univariate analysis, hypoalbuminemia, methotrexate dose, and nephrotoxic agents were significantly associated with time to clearance. In our multivariate model, hypoalbuminemia (p=0.009), methotrexate dose (p=0.002) and nephrotoxic agents (p=0.02) remained significantly associated with methotrexate clearance time. In addition, patients with hypoalbuminemia had a higher proportion of hyperbilirubinemia (28% vs. 13%, p=0.001) and significantly longer hospitalization (median 14 days vs. 5 days, p<0.001). There was no significant difference in the proportion of patients who experienced transaminitis, nephrotoxicity, mucositis, leukopenia, neutropenia, or pneumonitis.Conclusions: Hypoalbuminemia was associated with prolonged methotrexate clearance, and it remained significant after adjusting for the methotrexate dose and concomitant use of nephrotoxic agents. Patients with hypoalbuminemia were more likely to have bilirubin elevation, both markers of synthetic liver function. There were no differences in the toxicities of high dose methotrexate between groups owing to appropriate leucovorin rescue and good supportive care, demonstrating the safety of high dose methotrexate in patients with hypoalbuminemia, despite differences in the clearance time. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Polymorphisms in the ABCB1 gene and effect on outcome and toxicity in childhood acute lymphoblastic leukemia.

The membrane transporter P-glycoprotein, encoded by the ABCB1 gene, influences the pharmacokinetics of anti-cancer drugs. We hypothesized that variants of ABCB1 affect outcome and toxicity in childhood acute lymphoblastic leukemia (ALL). We studied 522 Danish children with ALL, 93% of all those eligible. Risk of relapse was increased 2.9-fold for patients with the 1199GA variant versus 1199GG (P=0.001), and reduced 61% and 40%, respectively, for patients with the 3435CT or 3435TT variants versus 3435CC (overall P=0.02). The degree of bone marrow toxicity during doxorubicin, vincristine and prednisolone induction therapy was more prominent in patients with 3435TT variant versus 3435CT/3435CC (P=0.01/P<0.0001). We observed more liver toxicity after high-dose methotrexate in patients with 3435CC variant versus 3435CT/TT (P=0.03). In conclusion, there is a statistically significant association between ABCB1 polymorphisms, efficacy and toxicity in the treatment of ALL, and ABCB1 1199G>A may be a new possible predictive marker for outcome in childhood ALL.

Pharmacology of high-dose methotrexate in patients with primary CNS lymphoma: A pharmacokinetic-pharmacodynamic analysis from the IELSG #20 trial.

2566 Background: This analysis was initiated to define the predictive value of the area-under-the-curve of high-dose methotrexate (AUCHD-MTX) in patients with primary central nervous system lymphoma (PCNSL), and to identify clinical and therapeutic variables that could be manipulated to improve MTX efficacy in these patients. Methods: We included 55 patients with PCNSL and available PK-data from the IELSG #20 trial, randomized to HD-MTX (n=30) or HD-MTX and HD-AraC (n=25). Individual AUCHD-MTX from population pharmacokinetic analysis was tested on drug toxicity and clinical outcome using multivariate logistic regression analysis and Cox hazards modeling. Results: AUCHD-MTX, IELSG score, and treatment group were significant predictors for treatment response (complete or partial response) in the adjusted model. AUCHD-MTX did not predict toxicity, with the exception of liver toxicity and neutropenia. A high AUCHD-MTX was associated with better event-free survival (EFS) (p=.01) and overall survival (OAS) (p=0.02). AUCHD-MTX and IELSG score were significant predictors for EFS and OAS in the adjusted model, with a hazard ratio of 0.82 and 0.73 per 100μ mol·L/h increase in AUCHD-MTX, respectively. Conclusions: Individualized dosing of HD-MTX might have the potential to improve clinical outcome in patients with PCNSL, even when given concurrently with HD-AraC. In the future, this could be done by using first-cycle PK- modeling with determination of potential dose adaptations for later cycles using Bayesian analysis. No significant financial relationships to disclose.

High-dose methotrexate for elderly patients with primary CNS lymphoma

The introduction of methotrexate (MTX)-based chemotherapy has improved median survival for patients with primary CNS lymphoma (PCNSL). Older age is a negative prognostic marker in patients with PCNSL and may increase the likelihood of MTX toxicity. We studied the response and adverse effects of intravenous high-dose MTX in patients who were 70 or more years of age at the time of diagnosis. We identified 31 patients at our institution diagnosed with PCNSL at age > or =70 years (median, 74 years) who were treated with high-dose MTX (3.5-8 g/m(2)) as initial therapy from 1992 through 2006. The best response to MTX was determined by contrast-enhanced MRI. Toxicity was analyzed by chart review. These 31 patients received a total of 303 cycles of MTX (median, eight cycles per patient). Overall, 87.9% of the cycles required dose reduction because of impaired creatinine clearance. In 30 evaluable patients, the overall radiographic response rate was 96.7%, with 18 complete responses (60%) and 11 partial responses (36.7%). Progression-free survival and overall survival were 7.1 months and 37 months, respectively. Grade I-IV toxicities were observed in 27 of 31 patients and included gastrointestinal disturbances in 58% (3.2% grade III), hematological complications in 80.6% (6.5% grade III), and renal toxicity in 29% (0% grade III/IV). High-dose MTX is associated with a high proportion of radiographic responses and a low proportion of grade III/IV toxicity in patients 70 or more years of age. High-dose MTX should be considered as a feasible treatment option in elderly patients with PCNSL.

Mutational Status in Genes of Folate Metabolism Is Associated with Toxicity of High-Dose Methotrexate in Patients with Immunocompetent Primary Central Nervous System Lymphoma.

Background: Outcome of patients with immunocompetent primary central nervous system lymphoma (PCNSL) has improved since the introduction of high-dose (HD) methotrexate (MTX). However, treatment may be perturbed by considerable toxicity. Acute toxicity comprises hematologic, renal, hepatic, pulmonary events and mucositis while neurologic impairment is essentially restricted to long-term survivors. MTX acts via inhibition of 5,10-methylentetrahydrofolate reductase (MTHFR) as well as thymidylate synthase (TYMS) in target cells what eventually results in decreased DNA synthesis. Intracellular uptake of folates is mediated by the reduced folate carrier (RFC). Two common MTHFR single nucleotide polymorphisms (SNPs) affect enzyme activity: 677 C→T and 1298A→C. A 28 base pair (bp) tandemly repeated sequence in the TYMS enhancer region (5′-UTR) containing either 2 or 3 repeats alters enzyme activity as does a 6 bp deletion (del) polymorphism in the 3′-UTR of TYMS. An RFC SNP (80G→A) is known to influence folate and MTX transport. We hypothesized that these polymorphisms may be directly linked to toxicity in PCNSL patients receiving high-dose MTX.Patients and methods: Genomic DNA was prospectively collected from patients (pts) with immunocompetent PCNSL who received HD MTX 4 g/m² every 2 weeks after enrolment onto a German multicenter trial. They had to have histological confirmation of their disease as well as adequate organ and bone marrow function. Genotyping of the two MTHFR and the RFC SNPs was performed by melting point analysis using the Light Cycler® technology. Genotyping of the TYMS 28bp polymorphism was performed by conventional PCR followed by agarose gel electrophoresis. The TYMS 6bp del polymorphism was analyzed by PCR, restriction enzyme digest and agarose gel electrophoresis. Hematologic (Hb, WBC, ANC, platelets) and non-hematologic toxicity (renal, hepatic, pulmonary, mucositis) were assessed prospectively and correlated with polymorphisms with respect to presumable functional relevance.Results: 123 pts with a median age of 62 (range, 27 – 80) years received a total of 506 cycles of high-dose MTX. 39 of 119 evaluable pts (33%) experienced any severe (°3/4) toxicity. Incidence of severe toxicity was significantly different for pts with MTHFR 677 TT (95%) when compared to CC/CT genotype (48%; p=.0024). Not considering hematologic parameters, severe toxicity was even more strongly associated with homozygosity for 677TT (p=.0006). A moderate association with lower ANC was found for MTHFR C677T (p=.049) while °3/4 neutropenia was strongly associated with RFC 80 GG vs. AA/GA (p=.0057). In hand, lower WBC nadirs occurred in pts with RFC 80 GG vs. AA/GA (p=.035).Conclusion: We demonstrate for the first time that pharmacogenetic studies might identify PCNSL pts who are at risk for severe acute hematologic and non-hematologic toxicity when treated with HD MTX. Correlation of (late) neurotoxicity with polymorphisms of folate metabolizing genes, however, will require longer follow-up.

Polymorphisms in genes of folate metabolism and effects of high-dose methotrexate in patients with primary central nervous system lymphoma

7558 Background: The antifolate methotrexate (MTX) is the single most effective agent in primary central nervous system lymphoma (PCNSL) when given intravenously in high doses. MTX inhibits 5,10-methylentetrahydrofolate reductase (MTHFR) as well as thymidylate synthase (TYMS) in target cells what eventually results in decreased DNA synthesis. Intracellular uptake of folates is mediated by the reduced folate carrier (RFC). Two common MTHFR single nucleotide polymorphisms (SNPs) affect enzyme activity: 677 C→T and 1298A→C. A 28 base pair (bp) tandemly repeated sequence in the TYMS enhancer region (5’-UTR) containing either 2 or 3 repeats alters enzyme activity as does a 6 bp deletion (del) polymorphism in the 3’-UTR of TYMS. An RFC SNP (80G→A) is known to influence folate and MTX transport. We hypothesized that these polymorphisms may be directly linked to toxicity in PCNSL patients receiving high-dose MTX. Methods: Genomic DNA was prospectively collected from patients (pts) who received high-dose (HD) MTX 4 g/m2 every 2 weeks after enrolment onto the German multicenter G-PCNSL-SG1 trial. Genotyping of the two MTHFR and the RFC SNPs was performed by melting point analysis using the Light Cycler technology. Genotyping of the TYMS 28bp polymorphism was performed by conventional PCR followed by agarose gel electrophoresis. The TYMS 6bp del polymorphism was analyzed by PCR, restriction enzyme digest and agarose gel electrophoresis. Response, hematologic (Hb, WBC, ANC, platelets) as well as cumulative incidence of non-hematologic toxicity (renal, pulmonary, mucositis) were assessed prospectively. Results: 123 pts are evaluvable for clinical parameters. Relative risk of any °III/IV toxicity was 26-fold higher for pts with 677TT when compared to CT or CC genotype (p = 0.009). °III/IV non-hematologic toxicity for TT was 10-fold higher than with CT or CC (p = 0.02). Significant differences for hematologic values were restricted to WBC and ANC and found to be associated with RFC 80 GG vs. AG/AA (p = 0.047). Conclusions: Pharmacogenetic studies may identify PCNSL pts who are at risk for severe hematologic and non-hematologic toxicity when treated with HD-MTX. No significant financial relationships to disclose.

Polymorphisms in Genes of Folate Metabolism and Response to High-Dose Methotrexate in Patients with Primary Central Nervous System Lymphoma.

The antifolate methotrexate (MTX) was shown to be the single most-effective agent in first-line treatment of patients with primary central nervous system lymphoma (PCNSL) when given intravenously in high doses. MTX inhibits 5,10-methylentetrahydrofolate reductase (MTHFR) as well as thymidylate synthase (TS) in target cells what eventually results in decreased DNA synthesis. Intracellular uptake of both folate and MTX is mediated by the reduced folate carrier (RFC). Genetic polymorphisms for all three proteins were described: a C to T base transition at nucleotide 667 (C677T) and an A to C transition at 1298 (A1298C) of MTHFR; a 28-base pair (bp) tandemly repeated sequence polymorphic in the numbers of the repeat (2R/2R; 3R/3R; and 2R/3R) in the 5′-UTR of TS; a 6bp insertion-(+6bp)/deletion(−6bp)-polymorphism in the 3′-UTR of TS; and a polymorphism at nucleotide 80 (G80A) of RFC. We hypothesized that these polymorphisms may be directly linked to response, survival and toxicity in patients with PCNSL who are treated with single high-dose MTX. We prospectively collected blood from 152 subjects who were enrolled into a German multicenter PCNSL trial. They were scheduled to receive HD-MTX 4 g/m2 every 2 weeks. Genomic DNA was extracted from mononuclear cells using QIAGEN DNA Blood Mini Kit®. Genotyping of the two MTHFR (C677T; A1298C) and the RFC (G80A) single nucleotide polymorphisms (SNPs) was performed by melting point analysis with Master Hybridization Probes® using the Light Cycler® technology. Genotyping of the TS 28bp tandem/triplet repeats in the 5′-UTR was performed by conventional PCR followed by high resolution agarose gel electrophoresis. The TS +6bp/−6bp polymorphism in the 3′-UTR was analyzed with PCR, followed by restriction enzyme digest with draI and agarose gel electrophoresis. The fragment sizes were 70 bp and 88 bp for the 6 bp insertion allele and 152 bp for the 6 bp deletion allele. Allele frequencies for heterozygosity and for homozygous mutations of the two MTHFR and the RFC SNPs as well as of the two TS polymorphisms were as expected for a Caucasian population. For the currently 120 evaluable patients logistic regression analysis, Armitage Trend test and Kaplan-Meier survival curves were performed to analyze the role of the polymorphisms as potential predictors for MTX response. Up to now, we only found a trend for an association between response to treatment and survival for the 2 MTHFR mutations. We will analyze haematological and non-haematological toxicities which will be presented at the meeting with updated results for survival and response in the patients who will have completed treatment until then.