Serum MTX Levels Research Articles

Genetic polymorphisms and clinical parameters associated with renal toxicity in Thai hematologic malignancy patients receiving high dose methotrexate

High-dose methotrexate (HD-MTX) is a widely used chemotherapy regimen for hematologic malignancies such as lymphomas and acute lymphoblastic leukemia, but its use can lead to adverse effects, including acute kidney injury (AKI), impaired liver function, and mucositis, causing extended hospital stays and delayed subsequent chemotherapy. Our study aimed to investigate the predictive factors for renal toxicities associated with HD-MTX in Thai patients undergoing treatment for hematologic malignancies. We enrolled 80 patients who underwent MTX-containing regimens, analyzing 132 chemotherapy cycles. The most common disease was primary central nervous system lymphoma (33%). Genetic polymorphisms were examined using the MassARRAY® system, identifying 42 polymorphisms in 25 genes. Serum creatinine and MTX levels were measured 24 and 48 h after MTX administration. For the primary outcome, we found that the allele A of MTRR rs1801394 was significantly related to renal toxicity (odds ratio 2.084 (1.001–4.301), p-value 0.047). Patients who exceeded the MTX threshold levels at 24 h after the dose had a significantly higher risk of renal toxicity (OR (95%CI) = 6.818 (2.350–19.782), p < 0.001). Multivariate logistic regression analysis with a generalized estimated equation revealed hypertension and age as independent predictors of increased MTX levels at 24 h after the given dose.

Hypoalbuminemia and not undernutrition predicts high-dose methotrexate-induced nephrotoxicity in children with acute lymphoblastic leukemia in resource-constrained centers.

The standard practice to mitigate high-dose methotrexate (HD-MTX)-induced nephrotoxicity (HMN) in acute lymphoblastic leukemia (ALL) is to monitor levels until serum MTX falls below a predefined threshold. It is not feasible in most resource-constrained centers. Literature on the various factors affecting HMN in these centers is limited, retrospective, and heterogeneous. Though hypoalbuminemia has been postulated as a risk factor for HMN, the relationship of undernutrition with HMN has not been studied. This prospective observational study consecutively enrolled children<12 years old with ALL receiving HD-MTX. Children with preexisting renal disease and exposed to nephrotoxic drugs two weeks preceding HD-MTX infusion were excluded. HD-MTX was administered over 24 hours (BFM-2009 protocol) with 12 hours of prehydration. Solitary MTX levels at 36 hours (MTX36) were outsourced, and 6-8 doses of leucovorin were given six-hourly. Hydration was continued till last dose of leucovorin. Various factors affecting HMN (rise in creatinine to 1.5 times baseline) were recorded: age, sex, type of ALL, risk group of ALL, first dose of MTX, dose of MTX, undernourishment, serum protein, and albumin along with C-reactive protein and MTX36 levels. Forty-four children who received 150 HD-MTX cycles were analyzed. HMN was seen in 14% of cycles. On univariate analysis, undernourishment, MTX36 levels, hypoproteinemia, and hypoalbuminemia were significantly associated with HMN. On multivariate analysis, hypoalbuminemia and MTX36 levels significantly predicted the development of HMN with odds ratios of 4.71 and 1.45. Hypoalbuminemia and solitary serum MTX levels predict HMN in centers where serial MTX level monitoring is not feasible.

Monitoring Of High-Dose Methotrexate (Mtx)-Related Toxicity and Mtx Levels in Children with Acute Lymphoblastic Leukemia: A Pilot-Study in Indonesia.

The administration of high-dose methotrexate (HD-MTX) requires an accurate monitoring of blood MTX levels to determine the regimen of leucovorin rescue and urine alkalinization to prevent toxicity. However, it is technically and logistically challenging to screen patients routinely in limited-resource settings. This study aimed to evaluate blood MTX levels at 24- and 48-hours from start of infusion in relation to clinical toxicity in childhood ALL. Methods: A prospective cohort study was conducted on 32 consecutive children with acute lymphoblastic leukemia (ALL) who had received at least one cycle of 1 g/m2 HD-MTX intravenous infusion as a part of consolidation treatment based on the 2013 Indonesian ALL Protocol. In total, 68 cycles were evaluated. Serum MTX concentrations were measured using enzyme immunoassay. MTX toxicity was categorized using common toxicity criteria (CTCAE) 3.0 version. The association between MTX level and clinical toxicity was assessed by non-parametric analysis. Results:The 24-hours MTX level was median 29.8 ng/mL (0.065 µmol/L) (IQR 8.1–390.6) with a modest decrease in 48-hours MTX serum level in all cycles (median 28.3 ng/mL and 0.062 µmol/L; IQR 0.35–28.7; p<0.05). The two most common toxicities were hepatotoxicity (32.2%) and neutropenia (30.9%). Nephrotoxicity and febrile neutropenia occurred in 8.8% and 5.8% of patients, respectively, with low percentage of mucositis (4.3%) and thrombocytopenia (5.6%) recorded. No statistically significant association was found between MTX levels and clinical toxicity, except for liver toxicity.Conclusion:Serum MTX levels at 24-hours and 48-hours are low, followed by only 4.4% grade III/IV hepatotoxicity and 26,4% grade III/IV neutropenia. There is no significant association between the clinical toxicity and MTX levels at the two points of measurement. An attempt to increase the MTX dose and/or to introduce a loading dose should be considered in subsequent ALL protocol as supported by further pharmacokinetic MTX studies in the Indonesian population.

When Baking Soda Goes on Shortage

▪Background: High dose methotrexate (HDMTX), defined as doses > 500-1000 mg/m2, is used to treat a variety of adult and pediatric malignancies. HDMTX can cause significant nephrotoxicity. Volume depletion and acidic urine are major risk factors for acute kidney injury. Precipitation of MTX crystals is most likely to occur in acidic urine when pH drops below 5.5. Increasing urine pH from 6.0 to 7.0 has been demonstrated to increase the solubility of MTX and its metabolites by five to eight-fold. Continuous intravenous (IV) sodium bicarbonate has been a simple long term solution for urinary alkalization allowing for rapid titration to accommodate fluctuations in urinary pH.1-2A recent breakdown in the supply chain of IV sodium bicarbonate has become a healthcare crisis compromising patient care. Sodium bicarbonate (8.4% and 7.5%) 50mL syringes are estimated to remain on back order until at least August 2017. Alternative sources, such as sodium acetate, are in limited supply as well.3-4 In a small case series, acetazolamide 500 mg IV q6H was reported to achieve adequate urinary alkalization, however efficacy of such a regimen has not been examined in a large population.5 Our lack of IV sodium bicarbonate created an urgent need to establish a practical alternative for urinary alkalization in patients receiving HDMTX.Methods: We designed a pilot algorithm for urinary alkalization in patients undergoing HDMTX (table 1). The algorithm relies on administration of IV acetazolamide to induce urinary alkalosis in combination with oral sodium bicarbonate to mitigate the metabolic acidosis induced by acetazolamide.5 MTX is not administered until urinary alkalization (urine pH > 7) is achieved, and the algorithm is continued until serum MTX levels are confirmed to be < 0.1 micromol/L. Additional supportive measures including hydration and leucovorin rescue are routinely provided per our institutional practice. Parameters for additional supportive measures are not defined by the algorithm and dose adjustment of leucovorin was left to the discretion of the treating physician in collaboration with the hematology/oncology clinical pharmacist.Results: Our algorithm was utilized in a patient on three separate encounters, all of which involved administration of HDMTX (8 gm/m2 IV) for primary central nervous system lymphoma. Time to urine pH > 7 using acetazolamide was < 2.5 hours allowing prompt initiation of therapy on admission. Urine pH < 7 was seen once while on IV sodium bicarbonate compared with a total of five times on our pilot algorithm; however the urine pH never dropped below 6.5 on our algorithm (table 1). Average length of stay was similar between both groups (five days with IV sodium bicarbonate and 4.67 days with our algorithm). No cycles resulted in elevations of serum creatinine, liver function tests, or mucositis. Utilizing a maximum dose of IV acetazolamide and oral sodium bicarbonate required for these patients, wholesale acquisition drug cost comparison for 24 hours of therapy is similar for both strategies.Conclusions: In summary, our pilot algorithm for urine alkalization demonstrated that using IV acetazolamide with oral sodium bicarbonate is a tolerable and effective alternative to the use of continuous sodium bicarbonate infusion when treating patients with HDMTX. The algorithm allowed safe treatment of patients with HDMTX at our institution during a period of no access to intravenous sodium bicarbonate. Our observations include prompt urine alkalinization, effective control of urine pH > 7, ease of administration and tolerability, and rapid reductions in plasma MTX concentrations. Limitation to the widespread use of acetazolamide includes metabolic acidosis though not seen in this limited experience. Notwithstanding this limitation, our algorithm demonstrates a viable alternative to sodium bicarbonate infusion and clearly merits further investigation. With the ongoing lack of access to IV sodium bicarbonate, we continue to utilize the algorithm for additional patients undergoing treatment with HDMTX. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

CTNI-61. PILOT STUDY OF REPEATED PLANNED GLUCARPIDASE FOLLOWING HIGH DOSE METHOTREXATE (HD-MTX) IN CNS LYMPHOMA (CNSL)

Abstract This study explores the repeated use of glucarpidase following HD-MTX in patients with CNSL. HD-MTX requires aggressive hydration and inpatient monitoring to prevent toxicity. Glucarpidase 50 units(u)/kg for delayed MTX clearance results in a reduction of systemic MTX levels without crossing the blood brain barrier. This study explores the use of 1000 or 2000 units of glucarpidase following repeated cycles of MTX 3–8 g/m2. Eligible adult patients had isolated CNSL, CrCl ≥ 60 mL/min, and KPS ≥ 50. Rituximab with MTX was administered for eight cycles. Glucarpidase was given 24 hours after each MTX infusion. MTX concentrations were monitored in serum and cerebrospinal fluid (CSF). Twelve patients enrolled to date and data are available for 50 doses of MTX (3 g/m2 (20), 6 g/m2 (21), 8 g/m2 (9)). Glucarpidase 1000u (14) or 2000u (36) resulted in at least a 95% reduction in serum MTX levels within 15 minutes following 49/50 doses. A 93% decrease was seen with the remaining dose. Glucarpidase was not detected in the CSF of 7 patients analyzed. Potentially cytotoxic MTX concentrations (10–6 M) were observed in CSF 1 hour (7/7) and 6 hours (4/7) after glucarpidase administration. Radiographic responses are evaluable in 9 patients: complete response (5), partial response (2), stable disease (1), and progressive disease (1). No grade 3 events were attributed to glucarpidase; one grade 4 event of anaphylaxis occurred. Anti-glucarpidase antibodies were detected in 2/5 patients analyzed. In summary, administration of low-dose glucarpidase 24 hours after MTX 3–8 g/m2 results in a reproducible rapid reduction in serum MTX levels in non-renally impaired patients. CSF MTX levels remain therapeutic and clinical response expected from MTX-based therapy does not appear compromised. Anti-glucarpidase antibodies may develop though significance remains unclear. Study is ongoing. Future directions will explore glucarpidase use for reduction of inpatient stay with HD-MTX.

COVD-23. PLANNED-USE GLUCARPIDASE FOR OUTPATIENT HIGH DOSE METHOTREXATE (HD-MTX) ADMINISTRATION IN PATIENTS WITH CNS LYMPHOMA (CNSL) DURING THE COVID-19 PANDEMIC

Infection with SARS CoV-2 virus has resulted in a global pandemic of COVID-19, a respiratory illness with a crude mortality rate of 3–4%. Risk of death is higher in the elderly and in patients with underlying comorbid conditions. When local incidence of COVID-19 is high, hospital resources are scarce and elective admissions and procedures are placed on hold. Patients with CNSL receiving first-line HD-MTX require admission for monitoring and aggressive hydration to prevent toxicity. This study explores the feasibility of planned-use glucarpidase, a recombinant bacterial enzyme that rapidly reduces serum MTX levels, to facilitate outpatient administration of HD-MTX. Eligible adult patients had isolated CNSL and had previously tolerated inpatient HD-MTX. MTX 3.5 g/m2 was administered in the outpatient setting with hydration. Patients returned 24 hours after MTX administration for glucarpidase 2000u and additional hydration. MTX level was determined by high pressure liquid chromatography (HPLC) 48 hours following MTX administration. To date, seven outpatient HD-MTX treatments have been administered to a total of three patients. In all cases, MTX levels were reduced to < 100 nmol/L at 48 hours. Three treatments resulted in grade 1 elevation of AST/ALT (two patients). One treatment resulted in a grade 2 creatinine increase. Creatinine returned to baseline following additional outpatient hydration. No patients required hospital admission. This study demonstrates feasibility of outpatient HD-MTX administration with planned-use glucarpidase during the COVID-19 pandemic. We are currently enrolling to a larger study of planned-use glucarpidase for repeated doses of outpatient HD-MTX.

275P - Primary central nervous system lymphoma treated with high-dose methotrexate and rituximab: Preliminary results in Vietnam

BackgroundCurrent treatment for primary central nervous system lymphoma involves high-dose methotrexate based regimen. In low&middle-income countries like Vietnam, a shortage of drugs and monitoring is common. The present study reports the first experience and preliminary results of 25 patients PCNSL treated with HD-MTX and RTX. MethodsFollowing Institutional Review Board approval by Vietnam National Institute for Cancer Control, a prospective study evaluating the treatment of histologically confirmed PCNSL with combined biweekly HD-MTX (8g/m2/dose) and weekly RTX (375 mg/m2/dose) for 8 cycles. Responders received consolidation treatment with 2 additional cycles, followed by maintenance with monthly HD-MTX for up to 12 months. Patients received aggressive hydration infusion to maintain a urine output of ≥ 100 ml/h and a urinary pH of > 7, until serum MTX levels had decreased to ≤ 0.1 µM/l. Serum MTX levels were monitored daily. Leucovorin rescue was initiated 24 h after completion of MTX infusion and administered at 50 mg IV every 6 h for the first 4 doses and then 30 mg IV until serum MTX levels were ≤0.1 µM/l. Leucovorin dosing was increased in cases of slow MTX clearance. The primary end point was radiographic response, and drug-related toxicity and secondary were survival. ResultsFrom 01/2017 to 12/2018, 25 patients were analysed (13 males and 12 females, median age 58.6). Following a mean of 10,72 cycles, the response rate and CR rate was 88% and 36%. The median PFS was 13 months and the OS has not yet been attained. MTX clearance was achieved by 72h in 198/268 cycles, and by 96h in 92%; 30.9% cycles needed escalation of leucovorin rescue dose. Toxicity: transient transaminitis (72%), mucotitis (59%) and diarhea (61.9%), febrile neutropenia (8%). Pneumonia was observed in 2 patients. 4 patients had renal dysfunction and 2 patient had dialysis. ConclusionsRTX combined HDMTX for PCNSL is possible in lower-middle income countries like Vietnam but should be done in experienced centers capable of close monitoring serum MTX levels to prevent toxicity. The addition of RTX to HD-MTX in the treatment of PCNSL may increase response rates and prolong PFS. The final results currently in progress will more definitively estimate the survival. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Germline Genetic Variations in Methotrexate Candidate Genes Are Associated with Pharmacokinetics and Outcome in Pediatric Acute Lymphoblastic Leukemia in China

BackgroundMethotrexate (MTX) is a key chemotherapeutic agent in the treatment of pediatric acute lymphoblastic leukemia (ALL). Nevertheless, MTX can cause severe adverse effects and toxicities. The aim of the present study was to identify genetic polymorphisms in candidate genes of the MTX pathway associated with MTX pharmacokinetics, toxicity, and outcome in ALL in China.MethodsThree hundred and twenty-two Chinese children with ALL in the standard-risk and medium-risk treatment branches from the Beijing Children's Hospital-2003 and Chinese Childhood Leukemia Group-2008 protocols were enrolled in this study. Sequenom MassARRAY was used to genotype 12 single nucleotide polymorphisms (SNPs) in 4 candidate genes of the MTX/folate pathway. A total of 1268 high-dose MTX (HD-MTX) courses were analyzed. The plasma MTX levels were evaluated at 48 h after the first dose of HD-MTX infusion. Oral mucositis during the consolidation therapy period was recorded.Results No polymorphism was associated with clinical features, prednisone response, and minimal residual disease (MRD) at day 33 and 78. Long-term outcome was better in SLCO1B1 rs4149056 T and TC allele carriers than patients with C allele (5-year RFS 92.3±1.6% vs. 27.8±23.2%,P<0.0001), in ABCB1 rs1128503 T and TC allele carriers than patients with C allele (92.7±1.6% vs. 78.2±6.9%, P=0.020), and in SCL19A1 rs2838958 AG and G allele carries than patients with A allele (93.9±1.6% vs. 83.0±4.2%, P =0.010). Multiple Cox regression analyses revealed an association of MRD at day 33 (hazard ratio 3.356; P=0.018), MRD at day 78 (hazard ratio 2.843; P=0.034), and SLCO1B1 rs4149056 (hazard ratio 8.073; P=0.002) with RFS in the study population.As to MTX pharmacokinetics, ABCB1 rs1128503 showed a significant association with serum MTX levels (P=0.004). SNPs (rs3788200, rs1131596, rs1051266) of the SLC19A1 gene were also associated with the plasma levels of MTX (P=0.003, 0.004, and 0.003, respectively). No association was found between oral mucositis with any polymorphism.Conclusions Genetic variations substantially influence the kinetics and response to HD-MTX therapy in childhood ALL. DisclosuresNo relevant conflicts of interest to declare.

Associations of novel genetic variations in the folate‐related and ARID5B genes with the pharmacokinetics and toxicity of high‐dose methotrexate in paediatric acute lymphoblastic leukaemia

High-dose methotrexate (HD-MTX) plays an important role in the consolidation therapy of acute lymphoblastic leukaemia (ALL) in many treatment regimens worldwide. However, there is a large interpatient variability in the pharmacokinetics and toxicity of the drug. We investigated the influence of single nucleotide polymorphisms (SNPs) in genes of the folate metabolic pathway, transporter molecules and transcription proteins on the pharmacokinetics and toxicity of MTX and 7-hydroxy-methotrexate (7-OH-MTX). 63 SNPs of 14 genes were genotyped and a total of 463 HD-MTX courses (administered according to the ALL-BFM 95 and ALL IC-BFM 2002 protocols) were analysed. Haematological, hepatic and renal toxicities, estimated by routine laboratory parameters were evaluated. Random forest and regression trees were used for variable selection and model building. Linear mixed models were established to prove the significance of the selected variables. SNPs (rs4948502, rs4948496, rs4948487) of the ARID5B gene were associated with the serum levels of MTX (P < 0·02), serum levels and area under the curve of 7-OH-MTX (P < 0·02) and with hypoproteinaemia (P = 0·004). SLCO1B1 rs4149056 also showed a significant association with serum MTX levels (P < 0·001). Our findings confirm the association of novel genetic variations in folate-related and ARID5B genes with the serum MTX levels and acute toxicity.

Calculated versus measured creatinine clearance for dosing methotrexate in the treatment of primary central nervous system lymphoma

High-dose methotrexate (HDMTX) (>or=3 g/m2), the cornerstone of therapy for primary CNS lymphoma (PCNSL), is commonly dosed using a measured 24 h creatinine clearance (CrCl) every 2-4 weeks. Because these collections are cumbersome and at times unreliable, the use of a calculated CrCl was evaluated as a potential alternative. A retrospective analysis was performed on data from all 287 treatment cycles from the 25 patients with PCNSL who participated in a multi-center phase II clinical trial of HDMTX conducted by the New Approaches to Brain Tumor Therapy (NABTT) CNS Consortium. The 25 patients had a median age of 61 years (range 32-75). Seventeen (68%) were men. The patients received a median of 14 (range 2-21) HDMTX treatments. For 256 of 287 treatments (89%), data were available to compare the measured and calculated (using the Cockcroft-Gault equation) CrCl. The average measured CrCl was 93 ml/min (95% CI, 89-96 ml/min), and the average calculated CrCl was 107 ml/min (95% CI, 102-112 ml/min). The Pearson correlation coefficient (r) was 0.49 (P<0.0001) between the measured and calculated CrCl. The average MTX dose determined using measured CrCl was 14.1 g (95% CI, 13.6-14.5 g), and the average MTX dose determined using calculated CrCl was 14.7 g (95% CI, 14.2-15.1 g). MTX doses based on measured and calculated CrCl were significantly correlated (r=0.72, P<0.0001). Of the 256 HDMTX treatments evaluated, 158 (62%) had reliable 48 h serum MTX levels documented. Forty-seven levels (30%) were within target range (0.3-1 micromol/l), 99 levels (62%) were below target range (<0.3 micromol/l), 12 levels (8%) were in the range associated with mild toxicity range (>1-3 micromol/l), and no levels were in the range associated with severe toxicity (>3 micromol/l). Of these 158 treatments, the use of a calculated rather than measured CrCl would have yielded an identical MTX dose for 48 treatments (30%), a higher MTX dose for 62 treatments (40%), and a lower MTX dose for 48 treatments (30%). This distribution was not significantly different among the subsets of below target, within target range, and above target MTX levels (P=0.87). In this cohort of patients with PCNSL, there is significant correlation between the calculated and measured CrCl. MTX doses determined using calculated and measured CrCl are not significantly different. For these patients, there is no clear association between the method of determining CrCl and serum MTX levels. As a result, calculated CrCl is a reasonable alternative to measured CrCl in this patient population and would avoid the inconvenience and potential inaccuracies associated with measured CrCl.

Calculated versus measured creatinine clearance for the dosing of methotrexate in patients with primary CNS lymphoma

1536 Background: High-dose methotrexate (HDMTX) (8g/m2), the cornerstone of therapy for primary central nervous system lymphoma (PCNSL), is commonly dosed using a measured 24-hour creatinine clearance (CrCl) every 2–4 weeks. Because these collections are cumbersome, costly, and at times unreliable, the use of a calculated CrCl was evaluated. Methods: A retrospective analysis was performed on data from all 25 patients (287 treatments) with PCNSL who participated in a multi-center phase II clinical trial of HDMTX conducted by the New Approaches to Brain Tumor Therapy (NABTT) CNS Consortium. Results: The 25 patients had a median age of 61 years (range 32–75 years). Seventeen patients (68%) were men. The patients received a median of 14 (range 2–21) HDMTX treatments. For 256 of 287 total treatments (89%), data were available to compare the measured and calculated (using the Cockcroft-Gault equation) CrCl. The average measured CrCl was 93±29 ml/min, and the average calculated CrCl was 107±43 ml/min. The correlation coefficient (r) was 0.66 (p&lt;0.001) between the measured and calculated CrCl. Of the 256 HDMTX treatments evaluated, 158 (62%) had reliable 48-hour serum MTX levels documented. Forty-eight levels (30%) were in the ideal range (0.3–1 μmol/L), 98 levels (62%) were lower (&lt;0.3 μmol/L), 12 levels (8%) were higher (&gt;1–3 μmol/L), and no levels were in the range associated with significant toxicity (&gt;3 μmol/L). Of these 158 treatments, the use of a calculated rather than measured CrCl would have yielded an identical MTX dose for 46 treatments (29%), a higher MTX dose for 62 treatments (39%), and a lower MTX dose for 50 treatments (32%). This distribution was not significantly different among the subsets of low, ideal, and high MTX levels (p=0.13). Conclusions: In this cohort of patients with PCNSL, there is a high correlation between the calculated and measured CrCl. For these patients, there is not a clear association between the method of determining CrCl and serum MTX levels. Therefore, the administered MTX doses using either method are likely to be similar. In this patient population, a calculated CrCl could be used to avoid the cost and inconvenience associated with measured CrCl. No significant financial relationships to disclose.

Effect of Polymorphisms in Folate Related Genes on Side Effects of High Dose MTX Treatment in Childhood Acute Lymphoblastic Leukemia.

Introduction. High dose (2 – 3 g/m2) methotrexate (MTX, an anti-folate) is used in the treatment of pediatric acute lymphoblastic leukemia (ALL) with side effects in a considerable number of children. We studied the prevalence of MTX related side effects and a possible relation with common polymorphisms in folate metabolism related genes in the treatment of childhood ALL.Methods. In this retrospective study, DNA was isolated from leukemic samples of 81 children with ALL. High risk (HR) ALL patients were treated with 4 courses of 3 g/m2, non-high risk (NHR) patients with 3 times 2g/m2. The following effects were monitored: serum MTX levels, transfusion need, liver toxicity, skin toxicity and hematological toxicity. Common gene mutations in methylenetetrahydrofolate reductase (MTHFR 677C>T and MTHFR 1298A>C), methionine synthase (MS 2756A>G), methionine synthase reductase (MTRR 66A>G), serine hydroxymethyl transferase (SHMT 1420C>T), methylenetetrahydrofolate dehydrogenase (MTHFD1 1958G>A), thymidylate synthase (TS 2R3R) and reduced folate carrier (RFC 80G>A) were detected by PCR-RFLP.Results. 57% of the patients had prolonged increased serum levels of MTX in at least 1 course. 59% patients had the MTX courses at the scheduled time, 35% had one course postponed and 6% 2 courses. Mucositis was observed in 22% patients after 1 out of 3 courses, 19% after 2 and 20% after 3 courses. 28% patients had 1 transfusion, 6% had 2 and 1% had 3 transfusions during the MTX courses. Transaminases were elevated 2 times above the normal upper level in 25% of the patients. Skin rash was observed in 32% patients.Using Mann Whitney analysis we found a significant relation between polymorphisms of the MTHFR 1298A>C and for the MTRR 66A>G genes and side effects. The MTHFR 1298A>C polymorphism was related to less transfusions (p<0.05). Recovery of WBC count in HR ALL patients tended to be slower in patients with a MTHFR 1298AA genotype (P=0.053). HR patients with a MTRR 66AG genotype had a slower recovery of platelet count (p=0.004)Conclusion. Common polymorphisms in the MTHFR (677C>T), MS, SHMT, TS, RFC, and MTHFD1 genes are not related to the occurrence of side effects of MTX treatment in childhood ALL. Polymorphisms in the MTHFR (1298A>C) and MTRR (66A>G) gene are related to hematological toxicity.

VARIABILITY IN DOSE INTENSITY OF HIGH-DOSE METHOTREXATE FOR NONMETASTATIC OSTEOSARCOMA

The authors evaluated their ability to maintain planned dosing schedules for high-dose methotrexate (HD-MTX) in patients with nonmetastatic osteosarcoma. Twenty-seven patients who received therapy according to 2 POG protocols (8651 and 9351), both of which included HD-MTX (12 g/m 2 /week for 2 consecutive weeks), between 1988 and 1998 were studied. Significantly fewer HD-MTX infusions were given on the second week to patients treated on POG 9351 (33 vs. 93%; p < .0001). The hydration guidelines were identical and there was no difference in peak serum MTX levels either within or between protocols. Differences in the administration of combination chemotherapy in 9351 compared to 8651 may have contributed to the increased toxicity associated with HD-MTX on 9351, although this is speculative. The use of HD-MTX should be carefully planned so that it does not decrease its dose intensity or that of other effective agents.

Transvaginal intra-amniotic injection of methotrexate in early ectopic pregnancy. Advantages over the laparoscopic approach

Methotrexate (MTX, 100 mg) was administered to 36 patients with early ectopic pregnancy locally, either under laparoscopic control into the distended fallopian tube (group A, n = 16), or transvaginally into the gestational sac directly, under ultrasound guidance (group B, n = 20). In cases with persistent β-hCG levels ( n = 7), an additional 50 mg of MTX solution was instilled into the affected tube, following transuterine tubal catheterization. Comparing the two different routes of MTX administration, it was shown that the resolution time (β-hCG < 20 mIU/ml) in group B was significantly shorter (2.4 ± 1.1 weeks vs. 4.1 ± 1.9 weeks in group A, P < 0.05), with a better success rate (100% and 88%, respectively). Serum MTX levels were found within a low range and no systemic side effects were noticed. In conclusion, direct intraovular MTX injection under ultrasound guidance proved superior to the laparoscopically-controlled ‘blind’ intratubal injection. A relatively high dose of MTX (100 mg) seems justified in order to shorten the resolution period, especially in cases with high initial β-hCG levels and/or fetal heart motion present.

Transient neurological disturbances induced by the chemotherapy of high-dose methotrexate for osteogenic sarcoma

Temporary neurologic abnormalities were observed in one out of 23 patients undergoing chemotherapy with high-dose methotrexate (HD-MTX) for osteogenic sarcoma. This patient developed sequential symptoms including alternative hemiparesis, dysarthria and altered consciousness 5 days after the second course of HD-MTX (8 gm/m2 by 6 h continuous infusion) with leucovorin rescue. Laboratory evaluations disclosed normal electrolytes, hemograms and non-toxic serum MTX levels at the onset of the symptoms. Computed tomography of the brain was normal but electroencephalography showed focal theta and delta slow waves over the right temporal-parietal-occipital area. The neurological symptoms resolved completely within 72 h.

Insulin and Diazoxide for Treatment of Cancer

Insulin is a growth stimulating hormone for several malignant tumors. In experimental breast cancer, diabetes induction with alloxan, strep-tozotocin or diazoxide leads to remission and intensifies the effect of an ovariectomy and of antiestrogen treatment. Clinically, in one of nine breast cancer patients, a partial remission of dermal metastases of seven months duration was achieved following a tamoxifen-induced remission by additional treatment with 200 mg diazoxide daily. In two other breast cancer patients, diazoxide led to stable disease of four (monotherapy) and eight months duration. Increased insulin levels can enhance the effect of simultaneous cytostatic therapy in a number of experimental systems. Initial clinical trials of combined therapy with methotrexate (MTX)/5-fluorouracil (5FU) and glucose/insulin indicate an increased cytostatic effect of this combination in some patients with breast cancer and in two patients with colon cancer, who were both pretreated with the same MTX/5FU regimen without glucose/insulin. In a case treated with high dose methotrexate therapy, the decrease of serum MTX-levels was slightly accelerated during and markedly delayed after the end of the glucose/ insulin-infusion.

Phase II and pharmacokinetic study of high-dose methotrexate in the treatment of advanced gynecologic malignancy: A Southwest Oncology Group trial

Fifteen patients with advanced or recurrent gynecologic malignancy were treated with high-dose methotrexate (HDMTX) (1–8 g/ M 2 ) and citrovorum factor rescue (10–100 mg/ M 2 ). One complete response (13%) and two improved responses occurred in eight patients (25%) with squamous cell carcinoma and one of seven patients (14%) with nonsquamous nontrophoblastic carcinoma had stable disease for 7 months. The median duration of survival in the squamous group was 9 months and in the nonsquamous groups 6.5 months. Mean serum MTX concentrations were proportional to the doses administered and typical two compartment plasma disappearance curves were seen. Adverse toxic reactions were not observed at serum MTX levels less than 7.8 × 10 −7, M at 24 hr and 1 × 10 −7 M at 48 hr post-MTX. Hematopoietic toxicity occurred most frequently with leukopenia observed in 19.5% of courses. Hepatic, renal, gastrointestinal, and dermatologic toxicities were observed infrequently. Drug-induced nephrotoxicity occurred in one patient and possibly related leukoencephalopathy occurred in another patient. On the basis of the relatively low response rate observed in this trial and the high expense of HDMTX therapy, the value of such therapy may be limited in advanced nontrophoblastic gynecologic cancer.