Systematic review of disease-modifying antirheumatic drugs for juvenile idiopathic arthritis

Efficacy of Atorvastatin Plus Conventional Disease-Modifying Antirheumatic Drugs on Disease Activity in Rheumatoid Arthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

METHODS

We queried the PubMed, Embase, Web of Science, and the CENTRAL (Cochrane Central Register of Controlled Trials) databases for this study. The pooled efficacy was evaluated using standardized mean differences. The inverse of the variance model was used for data pooling.

RESULTS

Based on the search, we identified 9 randomized controlled trials. The trials included 258 patients in the atorvastatin plus DMARD groups and 246 patients in the DMARD alone groups. The primary outcome was the change from baseline in the 2018 (209:228 Disease Activity Score in 28 Joints). Based on the Disease Activity Score in 28 Joints, disease activity in RA patients decreased significantly in patients given atorvastatin plus DMARD compared with patients given DMARD alone (standardized mean difference, -2.46; 95% confidence interval, -3.98 to -0.95; p = 0.0015; I2 = 97%; p < 0.01). Subgroup analysis did not identify any confounding factors, and no publication bias was detected in the meta-analysis.

CONCLUSIONS

The result supports that atorvastatin could be added to DMARDs to treat patients with RA.

Cyclic AMP in dendritic cells: A novel potential target for disease-modifying agents in asthma and other allergic disorders

Allergic diseases are immune disorders that are a global health problem, affecting a large portion of the world's population. Allergic asthma is a heterogeneous disease that alters the biology of the airway. A substantial portion of patients with asthma do not respond to conventional therapies; thus, new and effective therapeutics are needed. Dendritic cells (DCs), antigen presenting cells that regulate helper T cell differentiation, are key drivers of allergic inflammation but are not the target of current therapies. Here we review the role of dendritic cells in allergic conditions and propose a disease-modifying strategy for treating allergic asthma: cAMP-mediated inhibition of dendritic cells to blunt allergic inflammation. This approach contrasts with current treatments that focus on treating clinical manifestations of airway inflammation. Disease-modifying agents that target cAMP and its signalling pathway in dendritic cells may provide a novel means to treat asthma and other allergic diseases.

Successful treatment in a child with enthesitis-related arthritis involving the sternoclavicular joint: a case report

Background

Although the sternoclavicular joint (SCJ) may be involved in ankylosing spondylitis, rheumatic arthritis, and Behçet’s disease and participates in the systemic inflammatory process of arthritis, it is often neglected during routine rheumatologic clinical examinations. To the best of our knowledge, this is the first study to report etanercept treatment in juvenile idiopathic arthritis (JIA) with SCJ involvement.

Case presentation

In this study, we describe an unusual case of a child with juvenile idiopathic arthritis with an initial presentation of sternoclavicular mass. The patient (age, 14 years 10 months) presented with an insidious onset atraumatic swelling of the left SCJ and complained of right hip and bilateral ankle tenderness without an apparent cause. Initial ultrasonography indicated a heterogeneous mass in the left SCJ, while computed tomography identified mild swelling of the left SCJ with a thickened synovial lining, mild bone erosion, and some turbid fluid. The patient ultimately underwent left SCJ arthrotomy, during which tapping of the SCJ revealed 2 cc of yellowish fluid, inflammation and necrosis of tissues within the SCJ. A clear yellow joint fluid was aspirated, and testing revealed a negative culture result. The patient was diagnosed with JIA. The joint tenderness improved and erythrocyte sedimentation rate decreased after administering anti-tumor necrosis factor etanercept. An additional ultrasonography demonstrated that the initial imaging findings have been resolved. At the end of a 2-year follow-up period, the patient was completely symptom-free.

Conclusions

JIA with SCJ involvement is an uncommon presentation in adolescents. Etanercept may be a beneficial treatment for SCJ involvement in patients with JIA. The upper limbs showed no signs of limited range of motion during the follow-up period. Further studies are warranted to elucidate the efficacy of etanercept in JIA with sternoclavicular joint involvement.

Efficacy of opioids versus placebo in chronic pain: a systematic review and meta-analysis of enriched enrollment randomized withdrawal trials

Introduction

Opioids have been used for millennia for the treatment of pain. However, the long-term efficacy of opioids to treat chronic non-cancer pain continues to be debated. To evaluate opioids’ efficacy in chronic non-cancer pain, we performed a meta-analysis of published clinical trials for μ-opioid receptor agonists performed for US Food and Drug Administration approval.

Methods

MEDLINE and Cochrane trial register were searched for enriched enrollment randomized withdrawal studies (before June 2016). Selection criteria included: adults, ≥10 subjects per arm, any chronic pain condition, double-blind treatment period lasting ≥12 weeks, and all μ-agonist opioids approved in the USA.

Results

Fifteen studies met criteria. Opioid efficacy was statistically significant (p<0.001) versus placebo for pain intensity (standardized mean difference: −0.416), ≥30% and ≥50% improvement in pain (risk difference: 0.166 and 0.137), patient global impression of change (0.163), and patient global assessment of study medication (0.194). There were minor benefits on physical function and no effect on mental function.

Conclusion

Opioids are efficacious in the treatment of chronic non-cancer pain for up to 3 months in randomized controlled trials. This should be considered, alongside data on opioid safety, in the use of opioids for the treatment of chronic pain.

The clinical effectiveness and cost-effectiveness of abatacept, adalimumab, etanercept and tocilizumab for treating juvenile idiopathic arthritis: a systematic review and economic evaluation

BACKGROUND

Juvenile idiopathic arthritis (JIA) is characterised by joint pain, swelling and a limitation of movement caused by inflammation. Subsequent joint damage can lead to disability and growth restriction. Treatment commonly includes disease-modifying antirheumatic drugs (DMARDs), such as methotrexate. Clinical practice now favours newer drugs termed biologic DMARDs where indicated.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of four biologic DMARDs [etanercept (Enbrel(®), Pfizer), abatacept (Orencia(®), Bristol-Myers Squibb), adalimumab (Humira(®), AbbVie) and tocilizumab (RoActemra(®), Roche) - with or without methotrexate where indicated] for the treatment of JIA (systemic or oligoarticular JIA are excluded).

DATA SOURCES

Electronic bibliographic databases including MEDLINE, EMBASE, The Cochrane Library and the Database of Abstracts of Reviews of Effects were searched for published studies from inception to May 2015 for English-language articles. Bibliographies of related papers, systematic reviews and company submissions were screened and experts were contacted to identify additional evidence.

REVIEW METHODS

Systematic reviews of clinical effectiveness, health-related quality of life and cost-effectiveness were undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A cost-utility decision-analytic model was developed to compare the estimated cost-effectiveness of biologic DMARDs versus methotrexate. The base-case time horizon was 30 years and the model took a NHS perspective, with costs and benefits discounted at 3.5%.

RESULTS

Four placebo-controlled randomised controlled trials (RCTs) met the inclusion criteria for the clinical effectiveness review (one RCT evaluating each biologic DMARD). Only one RCT included UK participants. Participants had to achieve an American College of Rheumatology Pediatric (ACR Pedi)-30 response to open-label lead-in treatment in order to be randomised. An exploratory adjusted indirect comparison suggests that the four biologic DMARDs are similar, with fewer disease flares and greater proportions of ACR Pedi-50 and -70 responses among participants randomised to continued biologic DMARDs. However, confidence intervals were wide, the number of trials was low and there was clinical heterogeneity between trials. Open-label extensions of the trials showed that, generally, ACR responses remained constant or even increased after the double-blind phase. The proportions of adverse events and serious adverse events were generally similar between the treatment and placebo groups. Four economic evaluations of biologic DMARDs for patients with JIA were identified but all had limitations. Two quality-of-life studies were included, one of which informed the cost-utility model. The incremental cost-effectiveness ratios (ICERs) for adalimumab, etanercept and tocilizumab versus methotrexate were £38,127, £32,526 and £38,656 per quality-adjusted life year (QALY), respectively. The ICER for abatacept versus methotrexate as a second-line biologic was £39,536 per QALY.

LIMITATIONS

The model does not incorporate the natural history of JIA in terms of long-term disease progression, as the current evidence is limited. There are no head-to-head trials of biologic DMARDs, and clinical evidence for specific JIA subtypes is limited.

CONCLUSIONS

Biologic DMARDs are superior to placebo (with methotrexate where permitted) in children with (predominantly) polyarticular course JIA who have had an insufficient response to previous treatment. Randomised comparisons of biologic DMARDs with long-term efficacy and safety follow-up are needed to establish comparative effectiveness. RCTs for JIA subtypes for which evidence is lacking are also required.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015016459.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Imaging in paediatric rheumatology: Is it time for imaging?

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of arthritides characterized by chronic synovial inflammation that can lead to structural damage. The main objective of JIA therapies is to induce disease control to avoid disability in childhood. The advances in therapeutic effectiveness have created a need to search for imaging tools that describe more precisely disease activity in children with JIA. Musculoskeletal ultrasound and magnetic resonance imaging have demonstrated to be more sensitive than clinical examination in early detection of synovitis. These modalities can detect both inflammatory and destructive changes. The unique characteristics of the growing skeleton and a scarce validation of imaging in children result in important challenges in evaluating paediatric population. This review describes indications and limitations of these imaging techniques and suggests some advices for a rational use in the management of JIA in clinical practice.

Effect of miR-19a and miR-21 on the JAK/STAT signaling pathway in the peripheral blood mononuclear cells of patients with systemic juvenile idiopathic arthritis

Overexpression of the components of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway are key factors of the pathogenic mechanisms underlying systematic juvenile idiopathic arthritis (SJIA). The present study aimed to investigate the association between microRNA (miR)-19a, miR-21 and the JAK/STAT signaling pathway. A total of 20 patients with SJIA were included in the study, and peripheral blood mononuclear cells (PBMCs) from 20 normal controls were also collected. RNAiso was used to extract total RNA, and the RNA was then reverse transcribed into cDNA. Primers were designed to detect the mRNA of miR-19a and miR-21, and U6 was set as the internal parameter. In addition, the mRNA of STAT3, suppressor of cytokine signaling 3 (SOCS3), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) was detected, and β-actin was set as the internal parameter. Reverse transcription-quantitative polymerase chain reaction was performed to detect the expression levels of these proteins in patients with SJIA and control subjects, and non-parametric tests were used to analyze the statistical differences in 2^-ΔΔCq between the two groups. The expression levels of miR-19a and miR-21 were significantly lower in the SJIA group compared with the control group (P<0.05). SOCS3, TNF-α and STAT3 were shown to be the target genes of miR-19a and miR-21, as determined by Targetscan. The expression levels of STAT3, SOCS3, TNF-α and IL-6 mRNA were significantly higher compared with those of the control group (P<0.05). In the PBMCs of sthe patients with SJIA, miR-19a and miR-21 expression levels were lower compared with those of the control group, and the JAK/STAT signaling pathway was activated, which indicated that miR-19a and miR-21 may participate in the activation of the JAK/STAT signaling pathway.

The humanistic and economic burden of juvenile idiopathic arthritis in the era of biologic medication

Juvenile idiopathic arthritis (JIA) is a poorly understood, heterogeneous, incurable, inflammatory syndrome. Long-term outcomes are uncertain, and this painful condition can result in lifelong disability. JIA is associated with considerable financial and humanistic burden for those affected and the healthcare system. Early diagnosis and effective treatment are indicated to optimise outcomes. Modern treatment aims to achieve remission and preserve joint function by using disease-modifying antirheumatic drugs (DMARDs) early. DMARDs can be classified as conventional/traditional or biologic. Biologic medications may be more effective but cost approximately ten times more than traditional DMARDs. Decision-makers in healthcare are increasingly comparing the cost and consequences of alternative treatment strategies to guide resource allocation decisions. There have been few economic evaluations to date to guide medicines optimisation in JIA. This systematic review highlights the lack of existing evidence relating to the humanistic and economic burden of JIA in the era of biologic medication.

Effect of methotrexate on the mandibular development of arthritic rabbits

INTRODUCTION

Juvenile idiopathic arthritis affecting the temporomandibular joint (TMJ) can cause severe disturbances of the mandibular development. Methotrexate (MTX) is often administered as a common used remission-inducing agent to treat this disease. The aim of this study was to investigate the effect of low dose MTX on the mandibular growth in arthritic rabbits.

SUBJECTS AND METHODS

Eighteen 10-week-old female New Zealand white rabbits were randomly assigned to three groups with six animals in each group. After being sensitized to ovalbumin (OA), the first and the second group received intra-articular injections with OA. The first group remained untreated, the second was treated by weekly injections of MTX. Cephalograms were taken from each animal at 10, 13, 16, 19, and 22 weeks of age and six mandibular distances measured.

RESULTS

All distances showed an increase between 10 and 20 per cent, whereas growth was more accentuated in the sagittal dimension. Significant differences in the overall growth could be observed between the arthritic and the control animals and less accentuated between the arthritic and the MTX animals. In contrast, existing differences between the groups were not significant during the intervals, but time had the greatest influence on mandibular growth.

CONCLUSIONS

MTX seems to have a positive impact on growth in rabbits suffering from experimental arthritis of the TMJ.

Effect of methotrexate upon antigen-induced arthritis of the rabbit temporomandibular joint

BACKGROUND

Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) can cause severe growth disturbances of the craniomandibular system. Antigen-induced arthritis (AIA) of the rabbit TMJ is simulating the inflammatory process of the TMJ in JIA. The aim of this study was to investigate the effect of a systemic administration of methotrexate (MTX) on AIA in rabbits by means of three different histological staining methods.

METHODS

After sensitization, a bilateral arthritis of the TMJ was induced by an intra-articular administration of ovalbumin in 12 New Zealand white rabbits aged 10 weeks. From the 13th week of age, six of the 12 rabbits received weekly intramuscular injections of MTX, and the other six animals remained without therapy. Another six animals served as controls, receiving no treatment or intra-articular injections at all. After euthanasia at the age of 22 weeks, all TMJs were retrieved en bloc. Sagittal sections were cut and stained with haematoxylin-eosin (H-E), Safranin-O for the evaluation of the Mankin score and tartrate-resistant acid phosphatase (TRAP).

RESULTS

In the arthritis group, a chronic inflammation with degeneration of the articular cartilage was visible. In the MTX group, the signs of cartilage degeneration were significantly reduced compared with the arthritis group. In contrast, the joints in the control group were inconspicuous. A correlation between the Mankin score and TRAP-positive cells could be found.

CONCLUSIONS

Systemic administration of MTX seems to have a positive effect upon the inflammatory process in the rabbit TMJ but fails to eliminate the sign of arthritis completely.

Population-based cohort study on the risk of malignancy in East Asian children with juvenile idiopathic arthritis

BACKGROUND

To investigate the association and magnitude of risk between JIA, its associated treatment and cancer development in Taiwanese children.

METHODS

Nationwide population-based 1:4 age- and gender-matched retrospective cohort study was designed using the National Health Insurance Research Database of Taiwan. A cohort of 2,892 children <16 years old with JIA was formed as well as a non-JIA cohort of 11,568 in year 2003 to 2005. They were followed up till a diagnosis of malignancy or up to 8 years until 2010. Relative risk (RR), incidence rate ratio (IRR), and adjusted hazard ratio (aHR) of developing malignancy were calculated.

RESULTS

The female to male ratio was 0.79:1. There were 3 cases of incident cancer in the "MTX use, biologics-naïve" group, only 1 in the anti-TNF biologics-containing group and 29 in the "both MTX- and biologics-naïve" group, in comparison, there were 50 cases of cancer in the non-JIA comparator group. During a 16114.16 patient-years follow-up, the RR and IRR for developing a malignancy in both methotrexate- and anti-tumor necrosis factor (TNF) biologics-naïve JIA children were 2.75 (95% confidence interval, 1.75 - 4.32) and 3.21 (2.01 - 5.05), respectively. For leukemia, the IRR was 7.38 (2.50 - 22.75); lymphoma, 8.30 (1.23 - 69.79); and soft tissue sarcoma, 11.07 (0.84 - 326.4). The IRR of other cancers was 2.08 (1.11 - 3.71). The aHR on cancer risk was 3.14 (1.98 - 4.98) in methotrexate- and biologics-naïve group. There were no statistically significant increased risk in JIA patients treated with methotrexate and/or anti-TNF biologics.

CONCLUSIONS

Compared with children without JIA, children with JIA have 3-fold increase of risk on malignancy in East Asia. Seemingly neither methotrexate nor anti-TNF biologics increases the risk further.

Children with juvenile idiopathic arthritis frequently experience interruptions to their medical therapy

AIM

To study real-life experiences of drug treatment discontinuations and safety in a well-defined cohort of patients with juvenile idiopathic arthritis (JIA), over an eleven-year period in Uppsala County, Sweden.

METHODS

Clinical charts of all incident and prevalent cases of juvenile arthritis were reviewed prospectively by an experienced paediatric rheumatologist. Each patient file was supplemented retrospectively regarding hereditary diseases, clinical data and aspects of pharmacological treatment.

RESULTS

Severe adverse events from methotrexate or biological agents were rare, but 84 occasions of interrupted therapy due to adverse events or inefficacy were identified within 225 treatment periods (37.3%) in the 156 patients (108 girls and 48 boys) studied. The median observation period was 8.6 years after disease onset (minimum 1.33, maximum 17.5 years). Oral and subcutaneous methotrexate caused adverse events in 22.6% of the treatment periods and biological agents in 19.2% (p = 0.71). Discontinuation of treatment periods was equally common for methotrexate (38.7%) and biological agents (33.3%) (p = 0.53).

CONCLUSION

Our study shows a high percentage of interrupted medical therapies, due to adverse events or inefficacy, in children with JIA. Adverse events from methotrexate and biological agents were seldom severe. The results highlight the need for better predictive factors to guide therapy.

Clinical utility of etanercept in the treatment of arthritides in children and adolescents

Juvenile idiopathic arthritis (JIA) is a group of chronic inflammatory diseases affecting approximately 300,000 children and adolescents in the United States of unknown cause. It can affect children from the age of 0 years up to the age of 16 years. The International League of Associations of Rheumatology has defined seven subsets of JIA based on several factors including the number of affected joints and the involvement of other tissues; the prognosis for each affected child also depends on multiple factors including age of onset, number of joints involved, and systemic features. As with rheumatoid arthritis in adults, the goal of therapy is remission and resolution of disease activity; however, as a cure does not seem attainable in the near future, a reasonable goal of therapy is prevention of joint damage, inhibition of inflammation, and a high level of quality of life. Even with available therapies, many children with JIA enter adulthood with persistently active disease, suboptimal function, and impaired quality of life. Methotrexate remains the standard of care for children with JIA; etanercept was approved in 2000 in the United States for the treatment of JIA resistant to methotrexate. The efficacy and safety of etanercept therapy in children with JIA is reviewed and its place in the therapeutic regimen is discussed; the available long term data is also presented. The data presented was obtained from a PubMed search as well as a review of the references presented in the 2011 American College of Rheumatology Recommendations for the Treatment of Juvenile Idiopathic Arthritis and the 2013 Update. It is hoped that treatment with etanercept and other biologic therapies will lead to improved outcomes for children with JIA in the future.

A longterm prospective real-life experience with leflunomide in juvenile idiopathic arthritis

OBJECTIVE

To describe a clinical practice with leflunomide (LEF) in juvenile idiopathic arthritis (JIA).

METHODS

Patients with JIA seen between May 2008 and May 2012 and considered nonresponsive to methotrexate (MTX) were given LEF and prospectively followed. Primary outcome was a 28-joint Disease Activity Score (DAS28) of low disease activity (< 3.2) in less than 6 months. Childhood Health Assessment Questionnaire (CHAQ) scores and safety data were recorded.

RESULTS

Forty-three patients (33 female) were included with 25 (58.1%) polyarticular, 10 oligoarticular (7 extended; 3 persistent), 6 systemic, and 2 enthesitis-related. Ten (23.2%) were rheumatoid factor-positive and 7 (16.3%) had antinuclear antibodies. Prior drugs other than MTX: 11 (25.5%) chloroquine diphosphate + MTX and 2 (4.6%) sulfasalazine + MTX; mean prednisone dose was 6.4 ± 9.3 mg. The MTX dose prior to LEF was 14.5 ± 4.5 mg/m(2)/week. LEF dose and duration of therapy were 16.6 ± 5.2 mg/d and 3.6 ± 2.2 years, respectively. Nineteen patients (44.2%) interrupted LEF: 1 entered remission, 11 were nonresponsive, and 7 were intolerant (16.2%). Baseline DAS28 (5.57 ± 0.7) dropped to 3.7 ± 1.2 at final analysis (p < 0.001) and 16 patients (37.2%) had a low DAS28 [< 3.2; 12 (27.9%) while taking LEF + MTX and 4 (9.3%) while taking monotherapy]. At last followup, the number of patients with DAS28 > 5.1 dropped from 34 (79%) to 9 (20.9%) and CHAQ scores from 0.86 ± 0.7 to 0.44 ± 0.5 (p < 0.001).

CONCLUSION

LEF isolated or combined with MTX is effective and safe to treat JIA in patients refractory to MTX.

Refractory rheumatoid factor positive polyarthritis in a female adolescent already suffering from type 1 diabetes mellitus and Hashimoto's thyroiditis successfully treated with etanercept

Type 1 diabetes mellitus may be associated with many autoimmune diseases with the common autoimmune pathogenesis. We describe the case of a girl suffering from Type 1 diabetes mellitus and autoimmune Hashimoto's thyroiditis since the childhood and, due to the onset of Juvenile Idiopathic Arthritis during adolescence, for three years practiced therapy with an anti-TNF drug, etanercept . Currently her inflammatory markers are normal, arthritis is inactive and diabetes is well controlled. During the treatment with anti-TNF drug we observed a significative reduction of insulin dose, probably due to an increased tissue sensitivity secondary to the suppression of the activity of TNF-alpha. Several clinical trials that have evaluated the effect of immunomodulatory agents in diabetic patients, especially in those with recent onset of disease, were already performed but further studies of longer duration on a larger population are needed to assess the role of biologic drugs and immunotherapy in this group of patients.

Malignancy risks with biologic therapies

The management of rheumatoid arthritis (RA) dramatically changed in 1998 with the introduction of etanercept and infliximab for the treatment of RA and Crohn colitis. Nine biologic agents are currently in use for treating RA. However, speculation has grown that the long-term use of these biopharmaceuticals may alter normal immunosurveillance, thereby contributing to an individual's cancer risk. Whether malignancy is a consequence of rheumatoid inflammation or the therapies used to treat RA has been unclear until recently. This article addresses the growing data on the short- and long-term cancer risks associated with biologic use in RA.

Glucarpidase to combat toxic levels of methotrexate in patients

In January 2012, glucarpidase (Voraxaze^®) received approval from the US Food and Drug Administration for intravenous treatment of toxic plasma methotrexate concentrations due to impaired renal clearance. Methotrexate, an antifolate agent, has been used for over 60 years in the treatment of various cancers. High-dose methotrexate has been particularly useful in the treatment of leukemias and lymphomas. However, even with aggressive hydration and urine alkalinization, such regimens can lead to acute renal dysfunction, as indicated by decreases in urine production and concomitant increases in blood urea nitrogen and serum creatinine levels. Because methotrexate is largely excreted by the kidneys, this can greatly potentiate tissue damage. Toxic levels of blood methotrexate can be rapidly and effectively decreased by intravenous administration of glucarpidase. Glucarpidase is a recombinant form of carboxypeptidase G2, a bacterial enzyme that rapidly cleaves methotrexate to form the amino acid glutamate and 2,4-diamino-N¹⁰-methylpteroic acid. Catabolites of methotrexate are much less toxic than the parent compound, and are primarily excreted by hepatic mechanisms. Glucarpidase has been available on a compassionate basis since the 1990s, and a variety of case reports and larger clinical trials have demonstrated the safety and efficacy of this drug in patients ranging in age from infants to the elderly and in a variety of races and ethnic groups. Glucarpidase should not be administered within 2 hours of leucovorin, because this agent is a reduced folate which competes with methotrexate for the enzyme and glucarpidase inactivates leucovorin. Side effects of glucarpidase are rare and relatively mild, and include paraesthesia, flushing, nausea, vomiting, pruritus, and headache. Glucarpidase has seen limited use in intrathecal treatment of methotrexate toxicity for which it is also effective. Future applications of this enzyme in chemotherapy continue to be an active area of research.