The COMPARE head-to-head, randomized controlled trial of SEL-212 (pegadricase plus rapamycin-containing nanoparticle, ImmTOR™) versus pegloticase for refractory gout

OBJECTIVES

Serum urate (SU) lowering with PEGylated uricases in gout can reduce flares and tophi. However, treatment-emergent anti-drug antibodies adversely affect safety and efficacy and the currently approved PEGylated uricase pegloticase requires twice-monthly infusions. Investigational SEL-212 therapy aims to promote uricase-specific tolerance via monthly sequential infusions of a proprietary rapamycin-containing nanoparticle (ImmTOR) and pegadricase.

METHODS

COMPARE was a randomized, phase 2, open-label trial of SEL-212 vs pegloticase in adults with refractory gout. SEL-212 [ImmTOR (0.15 mg/kg) and pegadricase (0.2 mg/kg)] was infused monthly or pegloticase (8 mg) twice monthly for 6 months. The primary endpoint was the proportion of participants with SU <6 mg/dl for ≥80% of the time during 3 and 6 months. Secondary outcomes were mean SU, gout flares, number of tender and/or swollen joints and safety.

RESULTS

During months 3 and 6 combined, numerically more participants achieved and maintained a SU <6 mg/dl for ≥80% of the time with SEL-212 vs pegloticase (53.0% vs 46.0%, P = 0.181). The percentage reductions in SU levels were statistically greater during months 3 and 6 with SEL-212 vs pegloticase (-73.79% and -47.96%, P = 0.0161). Reductions in gout flare incidence and number of tender and/or swollen joints were comparable between treatments. There were numerical differences between the most common treatment-related adverse events of interest with SEL-212 and pegloticase: gout flares (60.2% vs 50.6%), infections (25.3% vs 18.4%) and infusion-related reactions (15.7% vs 11.5%), respectively. Stomatitis (and related terms) was experienced by eight participants (9.6%) with SEL-212 and none with pegloticase. Stomatitis, a known event for rapamycin, was associated with ImmTOR only.

CONCLUSIONS

SEL-212 efficacy and tolerability were comparable to pegloticase in refractory gout. This was associated with a substantial reduction in treatment burden with SEL-212 due to decreased infusion frequency vs pegloticase.

CLINICAL TRIAL REGISTRATION

NCT03905512.

Polyvinylpyrrolidone-Coated Cubic Hollow Nanocages of PdPt3 and PdIr3 as Highly Efficient Self-Cascade Uricase/Peroxidase Mimics

Uricase-catalyzed uric acid (UA) degradation has been applied for hyperuricemia therapy, but this medication is limited by H2O2 accumulation, which can cause oxidative stress of cells, resulting in many other health issues. Herein, we report a robust cubic hollow nanocage (HNC) system based on polyvinylpyrrolidone-coated PdPt3 and PdIr3 to serve as highly efficient self-cascade uricase/peroxidase mimics to achieve the desired dual catalysis for both UA degradation and H2O2 elimination. These HNCs have hollow cubic shape with average wall thickness of 1.5 nm, providing desired synergy to enhance catalyst's activity and stability. Density functional theory calculations suggest the PdIr3 HNC surface tend to promote OH*/O* desorption for better peroxidase-like catalysis, while the PdPt3 HNC surface accelerates the UA oxidation by facilitating O2-to-H2O2 conversion. The dual catalysis power demonstrated by these HNCs in cell studies suggests their great potential as a new type of nanozyme for treating hyperuricemia.

Pipeline Therapies for Gout

PURPOSE OF REVIEW

Despite effective available treatments, gout management is often unsuccessful in getting patients to target serum urate goal and in managing flares in the setting of comorbidities. Studies addressing future treatment options for short- and long-term management are reviewed.

RECENT FINDINGS

URAT-1 blocking agents have been helpful but have had limitations related to effects on renal function, lack of efficacy with renal impairment, and potential to increase renal stones. Dotinurad may function in the setting of decreased renal function. Arhalofenate has anti-URAT-1 activity and may also blunt gout flares. A new xanthine oxidase inhibitor (XOI), tigulixostat, is under study. New uricase treatments manufactured in combination with agents that can reduce immunogenicity may make uricase treatment simpler. A unique strategy of inhibiting gut uricase may offer the benefits of avoiding systemic absorption. For gout flares, IL-1β inhibitor studies in progress include different dosing schedules. Dapansutrile, an oral agent under investigation, inhibits activation of the NLRP3 inflammasome and may be an effective anti-inflammatory. New treatments for gout that are under study may work in the setting of comorbidities, simplify management, utilize new mechanisms, or have reduced side effects.

In vivo study of newly developed albumin-conjugated urate oxidase for gout treatment

BACKGROUND

Exogenously providing engineered Uox with enhanced half-life is one of the important urate-lowering treatments for gout. The potential of PAT101, a recombinant human albumin (rHA)-conjugated variant, was evaluated and compared as a novel gout treatment through various in vivo studies with PAT101 and competing drugs.

METHODS

PAT101 was produced by site-specific conjugation of rHA and Aspergillus flavus Uox (AfUox-rHA) through clickable non-natural amino acid (frTet) and Inverse electron demand Diels-Alder (IEDDA) reaction. In vivo pharmacokinetics, efficacy tests and in vitro immunogenetic assay were performed after single or multiple doses of PAT101 and its competitors in BALB/c mice, transgenic (TG) mice, Sprague-Dawley (SD) rats, and non-human primate (NHP).

RESULTS

The half-life of PAT101 in single-dose treated TG mice was more than doubled compared to pegloticase. In SD rats with 4 weeks of repeated administration of rasburicase, only 24% of Uox activity remained, whereas in PAT101, it was maintained by 86%. In the Uox KO model, the survival rate of PAT101 was comparable to that of pegloticase. In addition, human PBMC-based CD4+/CD8+ T-cell activation analysis demonstrated that PAT101 has a lower immune response compared to the original drug, rasburicase.

CONCLUSION

All results suggest that this rHA-conjugated AfUox, PAT101, can be provided as a reliable source of Uox for gout treatment.

Pegloticase co-administered with high MW polyethylene glycol effectively reduces PEG-immunogenicity and restores prolonged circulation in mouse

The interactions between polymers and the immune system remains poorly controlled. In some instances, the immune system can produce antibodies specific to polymer constituents. Indeed, roughly half of pegloticase patients without immunomodulation develop high titers of anti-PEG antibodies (APA) to the PEG polymers on pegloticase, which then quickly clear the drug from circulation and render the gout treatment ineffective. Here, using pegloticase as a model drug, we show that addition of high molecular weight (MW) free (unconjugated) PEG to pegloticase allows us to control the immunogenicity and mitigates APA induction in mice. Compared to pegloticase mixed with saline, mice repeatedly dosed with pegloticase containing different MW or amount of free PEG possessed 4- to 12- fold lower anti-PEG IgG, and 6- to 10- fold lower anti-PEG IgM, after 3 rounds of pegloticase dosed every 2 weeks. The markedly reduced APA levels, together with competitive inhibition by free PEG, restored the prolonged circulation of pegloticase to levels observed in APA-naïve animals. In contrast, mice with pegloticase-induced APA eliminated nearly all pegloticase from the circulation within just four hours post-injection. These results support the growing literature demonstrating free PEG may effectively suppress drug-induced APA, which in turn may offer sustained therapeutic benefits without requiring broad immunomodulation. We also showed free PEG effectively blocked the PEGylated protein from binding with cells expressing PEG-specific B cell receptors. It provides a template of how we may be able to tune the interactions and immunogenicity of other polymer-modified therapeutics. STATEMENT OF SIGNIFICANCE: A major challenge with engineering materials for drug delivery is their interactions with the immune system. For instance, our body can produce high levels of anti-PEG antibodies (APA). Unfortunately, the field currently lack tools to limit immunostimulation or overcome pre-existing anti-PEG antibodies, without using broad immunosuppression. Here, we showed that simply introducing free PEG into a clinical formulation of PEG-uricase can effectively limit induction of anti-PEG antibodies, and restore their prolonged circulation upon repeated dosing. Our work offers a readily translatable method to safely and effectively restore the use PEG-drugs in patients with PEG-immunity, and provides a template to use unconjugated polymers with low immunogenicity to regulate interactions with the immune system for other polymer-modified therapeutics.

Mechanisms and rationale for uricase use in patients with gout

Xanthine oxidase inhibitors such as allopurinol and febuxostat have been the mainstay urate-lowering therapy (ULT) for treating hyperuricaemia in patients with gout. However, not all patients receiving oral ULT achieve the target serum urate level, in part because some patients cannot tolerate, or have actual or misconceived contraindications to, their use, mainly due to comorbidities. ULT dosage is also limited by formularies and clinical inertia. This failure to sufficiently lower serum urate levels can lead to difficult-to-treat or uncontrolled gout, usually due to poorly managed and/or under-treated gout. In species other than humans, uricase (urate oxidase) converts urate to allantoin, which is more soluble in urine than uric acid. Exogenic uricases are an exciting therapeutic option for patients with gout. They can be viewed as enzyme replacement therapy. Uricases are being used to treat uncontrolled gout, and can achieve rapid reduction of hyperuricaemia, dramatic resolution of tophi, decreased chronic joint pain and improved quality of life. Availability, cost and uricase immunogenicity have limited their use. Uricases could become a leading choice in severe and difficult-to-treat gout as induction and/or debulking therapy (that is, for lowering of the urate pool) to be followed by chronic oral ULT. This Review summarizes the evidence regarding available uricases and those in the pipeline, their debulking effect and their outcomes related to gout and beyond.

Polyethylene Glycol-Like Brush Polymer Conjugate of a Protein Drug Does Not Induce an Antipolymer Immune Response and Has Enhanced Pharmacokinetics than Its Polyethylene Glycol Counterpart

Protein therapeutics, except for antibodies, have a short plasma half-life and poor stability in circulation. Covalent coupling of polyethylene glycol (PEG) to protein drugs addresses this limitation. However, unlike previously thought, PEG is immunogenic. In addition to induced PEG antibodies, ≈70% of the US population has pre-existing anti-PEG antibodies. Both induced and preexisting anti-PEG antibodies result in accelerated drug clearance, reduced clinical efficacy, and severe hypersensitivity reactions that have limited the clinical utility of uricase, an enzyme drug for treatment for refractory gout that is decorated with a PEG corona. Here, the authors synthesize a poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) conjugate of uricase that decorates the protein with multiple polymer chains to create a corona to solve these problems. The resulting uricase-POEGMA is well-defined, has high bioactivity, and outperforms its PEG counterparts in its pharmacokinetics (PK). Furthermore, the conjugate does not induce anti-POEGMA antibodies and is not recognized by anti-PEG antibodies. These findings suggest that POEGMA conjugation may provide a solution to the immunogenicity and antigenicity limitations of PEG while improving upon its PK benefits. These results transcend uricase and can be applied to other PEGylated therapeutics and the broader class of biologics with suboptimal PK.

Self-Cascade Uricase/Catalase Mimics Alleviate Acute Gout

Uricase-based therapies are limited for gout partially due to the accumulation of H2O2 in an arthrosis environment with slow metabolism. To tackle this limitation, previous studies adopted a cascade reaction between the degradation of uric acid (UA) and timely elimination of H2O2 using complicated composites of uricase and catalase (CAT)/CAT-like nanozyme. Herein, the self-cascade nanozyme Pt/CeO2 with high efficiency toward simultaneous UA degradation and H2O2 elimination is demonstrated on the basis of both uricase- and CAT-like activities in Pt, Ir, Rh, and Pd platinum-group metals. With an optimized molar ratio of Pt and CeO2, Pt/CeO2 (1/5) not only does better in degrading UA but also has excellent reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenging activities. In monosodium urate (MSU)-induced acute gout rats, Pt/CeO2 nanozyme markedly alleviates pain along with joint edema, thus improving gait claudication and tissue inflammation. These results provide novel insights into strategies of an efficient enzyme-mimetic treatment for gout.

Pretreatment and Coadministration With Methotrexate Improved Durability of Pegloticase Response: An Observational, Proof-of-Concept Case Series

BACKGROUND/OBJECTIVE

Pegloticase is used for treatment of refractory gout, which has failed maximal medical management, but only 42% of patients respond completely to treatment because of the presumed development of antidrug antibodies, which rapidly clear the pegloticase molecule. Immunomodulatory medications temper antidrug antibody development in other diseases. The aim of this case series was to investigate the utility of adding methotrexate to a pegloticase regimen to increase the response durability in a real-world practice setting.

METHODS

In this multicenter, proof-of-concept, observational case series, refractory tophaceous gouty arthropathy patients being started on pegloticase 8 mg every 2 weeks were identified. The patients began oral methotrexate 15 mg/wk and folic acid 1 mg/d, 1 month prior to the initial pegloticase administration, and continued throughout pegloticase treatment. Responders were defined by demonstrating ≥80% of preinfusion serum uric acid (sUA) levels <6.0 mg/dL between months 3 and 6.

RESULTS

Ten sequential patients, aged 35 to 80 years, identified between May 2017 and June 2018, from 3 separate infusion centers were followed for up to 10 months. All patients maintained methotrexate 15 mg/wk without dose adjustments. There were 143 total pegloticase infusions. All 10 patients completed a full course of pegloticase treatment with 100% response and no infusion reactions. No patients stopped pegloticase therapy because of increased sUA, loss of response, or gout flares.

CONCLUSIONS

Pretreatment and coadministration of methotrexate with pegloticase resulted in 100% maintenance of pegloticase sUA response with no infusion reactions. These data support the potential use of immunomodulation with methotrexate to improve durability of pegloticase response in the treatment of refractory gout.

Interventions for tophi in gout

BACKGROUND

Tophi develop in untreated or uncontrolled gout. This is an update of a Cochrane Review first published in 2014.  OBJECTIVES: To assess the benefits and harms of non-surgical and surgical treatments for the management of tophi in gout.

SEARCH METHODS

We updated the search of Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase databases to 28 August 2020.

SELECTION CRITERIA

We included all published randomised controlled trials (RCTs) or controlled clinical trials examining interventions for tophi in gout in adults.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included one trial in our original review. We added four more trials (1796 participants) in this update. One had three arms; pegloticase infusion every two weeks (biweekly), monthly pegloticase infusion (pegloticase infusion alternating with placebo infusion every two weeks) and placebo. Two studies looked at lesinurad 200 mg or 400 mg in combination with allopurinol. One trial studied lesinurad 200 mg or 400 mg in combination with febuxostat. One trial compared febuxostat 80 mg and 120 mg to allopurinol. Two trials were at unclear risk of performance and detection bias due to lack of information on blinding of participants and personnel. All other trials were at low risk of bias. Moderate-certainty evidence (downgraded for imprecision; one study; 79 participants) showed that biweekly pegloticase resolved tophi in 21/52 participants compared with 2/27 on placebo (risk ratio (RR) 5.45, 95% confidence interval (CI) 1.38 to 21.54; number needed to treat for a benefit (NNTB) 3, 95% CI 2 to 6). Similar proportions of participants receiving biweekly pegloticase (80/85) had an adverse event compared to placebo (41/43) (RR 0.99, 95% CI 0.91 to 1.07). However, more participants on biweekly pegloticase (15/85) withdrew due to an adverse event compared to placebo (1/43) (RR 7.59, 95% CI 1.04 to 55.55; number needed to treat for a harm (NNTH) 7, 95% CI 4 to 16). More participants on monthly pegloticase (11/52) showed complete resolution of tophi compared with placebo (2/27) (RR 2.86, 95% CI 0.68 to 11.97; NNTB 8, 95% CI 4 to 91). Similar numbers of participants on monthly pegloticase (84/84) had an adverse event compared to placebo (41/43) (RR 1.05, 95% CI 0.98 to 1.14). More participants on monthly pegloticase (16/84) withdrew due to adverse events compared to placebo (1/43) (RR 8.19, 95% CI 1.12 to 59.71; NNTH 6, 95% CI 4 to 14). Infusion reaction was the most common reason for withdrawal. Moderate-certainty evidence (2 studies; 103 participants; downgraded for imprecision) showed no clinically significant difference for complete resolution of target tophus in the lesinurad 200 mg plus allopurinol arm (11/53) compared to the placebo plus allopurinol arm (16/50) (RR 0.40, 95% CI 0.04 to 4.57), or in the lesinurad 400 mg plus allopurinol arm (12/48) compared to the placebo plus allopurinol arm (16/50) (RR 0.79, 95% CI 0.42 to 1.49). An extension study examined lesinurad 200 mg or 400 mg in combination with febuxostat, or placebo (low-certainty evidence, downgraded for indirectness and imprecision). Participants on lesinurad in the original study continued (CONT) on the same dose. Lesinurad 400 mg plus febuxostat may be beneficial for tophi resolution; 43/65 in the lesinurad 400 mg CONT arm compared to 38/64 in the lesinurad 200 mg CONT arm had tophi resolution (RR 1.11, 95% CI 0.85 to 1.46). Lesinurad 400 mg plus febuxostat may result in no difference in adverse events; 57/65 in the lesinurad 400 mg CONT arm had an adverse event compared to 50/64 in lesinurad 200 mg CONT arm (RR 1.12, 95% CI 0.96 to 1.32). Lesinurad 400 mg plus febuxostat may result in no difference in withdrawals due to adverse events; 10/65 participants in the lesinurad 400 mg CONT arm withdrew due to an adverse event compared to 10/64 participants in the lesinurad 200 mg CONT arm (RR 0.98, 95% CI 0.44 to 2.20). Lesinurad 400 mg plus febuxostat may result in no difference in mean serum uric acid (sUA), which was 3 mg/dl in the lesinurad 400 mg CONT group compared to 3.9 mg/dl in the lesinurad 200 mg CONT group (mean difference -0.90, 95% CI -1.51 to -0.29). Participants who were not on lesinurad in the original study were randomised (CROSS) to lesinurad 200 mg or 400 mg, both in combination with febuxostat. Low-certainty evidence downgraded for indirectness and imprecision showed that lesinurad 400 mg (CROSS) may result in tophi resolution (17/34) compared to lesinurad 200 mg (CROSS) (14/33) (RR 1.18, 95% CI 0.70 to 1.98). Lesinurad 400 mg in combination with febuxostat may result in no difference in adverse events (33/34 in the lesinurad 400 mg CROSS arm compared to 27/33 in the lesinurad 200 mg (CROSS); RR 1.19, 95% CI 1.00 to 1.41). Lesinurad 400 mg plus febuxostat may result in no difference in withdrawals due to adverse events, 5/34 in the lesinurad 400 mg CROSS arm withdrew compared to 2/33 in the lesinurad 200 mg CROSS arm (RR 2.43, 95% CI 0.51 to 11.64). Lesinurad 400 mg plus febuxostat results in no difference in sUA (4.2 mg/dl in lesinurad 400 mg CROSS) compared to lesinurad 200 mg (3.8 mg/dl in lesinurad 200 mg CROSS), mean difference 0.40 mg/dl, 95% CI -0.75 to 1.55.

AUTHORS' CONCLUSIONS

Moderate-certainty evidence showed that pegloticase is probably beneficial for resolution of tophi in gout. Although there was little difference in adverse events when compared to placebo, participants on pegloticase had more withdrawals due to adverse events. Lesinurad 400 mg plus febuxostat may be beneficial for tophi resolution compared with lesinurad 200 mg plus febuxostat; there was no difference in adverse events between these groups. We were unable to determine whether lesinurad plus febuxostat is more effective than placebo. Lesinurad (400 mg or 200 mg) plus allopurinol is probably not beneficial for tophi resolution, and there was no difference in adverse events between these groups. RCTs on interventions for managing tophi in gout are needed, and the lack of trial data is surprising given that allopurinol is a well-established treatment for gout.

Rasburicase-induced Methemoglobinemia: A Case Report and Literature Review

Rasburicase is a recombinant urate oxidase enzyme indicated for tumor lysis syndrome, a potential life-threatening oncologic emergency that occurs most commonly during initial chemotherapy for hematological malignancies. As a result of the defects in the physiological antioxidant pathway, erythrocytes of patients with glucose-6-phosphate dehydrogenase deficiency are not protected against the oxidizing stress exerted by hydrogen peroxide generated with the administration of rasburicase. The authors report a 14-year-old patient, diagnosed with T-cell acute lymphoblastic leukemia, who developed methemoglobinemia and hemolytic anemia with low oxygen saturation after starting steroids, hyperhydratation, and rasburicase administration. The complications resolved with supportive therapy only.

Advanced germ cell tumors and chemotherapy in G6PD deficient patients: Yes to chemotherapy but no to rasburicase and some premedications

PURPOSE

Glucose-6 phosphate dehydrogenase (G6PD) deficiency has an estimated prevalence of 5 -7.5% of the global population. Administration of some drugs in G6PD deficient patients may result in clinical conditions of varying severity, including potentially fatal sequels. For these reasons, in case of G6PD deficiency, the use of high dose toxic chemotherapy regimens in potentially curable malignancies with associated risk of tumor lysis syndrome, such as in advanced germ cell tumors, raises both physicians' preoccupations and issues for safeguard patients' health. Nonetheless no systematic information is actually available for safety in premedication to be administered, chemotherapy regimens adopted, and supportive care drugs needed to be provided in some particular situations.

METHODS

We present a case of a patient with metastatic testicular cancer and known g6pd deficiency, admitted in our department. We also performed a literature review in tree medical libraries searching for articles addressing the overmentioned security issues.

RESULTS

Available literature is particularly scant. nonetheless, there is no evidence contradicting the administration of cytotoxic chemotherapy to G6PD deficient individuals. Our patient was able to complete the preplaned chemotherapy cycles, without any complications.

CONCLUSION

Given the absence of data supporting the limitation of chemotherapy to G6PD deficient patients, the latter should not be deprived of the indicated antineoplastic treatment. However, certain premedication agents must be avoided. Continuous patient monitoring during treatment may alleviate physicians' and patients' anxiety and preoccupations.

The effect of immunomodulators on the efficacy and tolerability of pegloticase: a systematic review

INTRODUCTION

Pegloticase is a recombinant PEGylated uricase that converts relatively insoluble urate to highly water-soluble allantoin, which is readily excreted by the kidneys. It is the first and only biologic treatment indicated for refractory or uncontrolled gout. Clinical trials showed a 6-month pegloticase responder rate of 42%, with the non-responder rate largely being attributed to the development of high-titer anti-drug antibodies (ADAs) against pegloticase. Immunomodulation attenuates ADA formation to biologics in a number of autoimmune conditions, but their use with pegloticase for uncontrolled gout is less established. This systematic review examined published cases of refractory gout patients treated with immunomodulation in combination with pegloticase.

METHODS

Published cases of immunomodulation with pegloticase were identified in a PubMed search and in abstract databases of major rheumatology society meetings (2012-2020). Duplicate and review articles were excluded, as were those that did not include cases of pegloticase use with immunomodulation. Cases with off-label pegloticase administration schedules were also excluded. Pegloticase response was defined according to each study's specified standard.

RESULTS

Ten publications describing 82 cases of pegloticase use in the setting of immunomodulation were identified. Overall pegloticase response rate was 82.9%. Patients co-treated with an individual immunomodulator had the following response rates: methotrexate: 87.5% (35 of 40 patients), mycophenolate mofetil: 86.4% (19 of 22 patients vs. pegloticase monotherapy [placebo]: 40% [4 of 10 patients]), azathioprine: 63.6% (7 of 11 patients), and leflunomide: 66.7% (4 of 6 patients). A single patient was co-treated with cyclosporin and was a responder. The two patients treated with more than one immunomodulator were both responders.

CONCLUSION

Published reports suggest that immunomodulation co-therapy has the potential to markedly improve pegloticase responder rates in patients with uncontrolled gout.

Therapeutic Strategies for the Treatment of Chronic Hyperuricemia: An Evidence-Based Update

This article aims to critically review the evidence on the available therapeutic strategies for the treatment of hyperuricemia. For this reason, several papers were reviewed. Xanthine oxidase inhibitors are the safest and most effective uric acid lowering drugs for the management of chronic hyperuricemia, while the efficacy of uricosuric agents is strongly modulated by pharmacogenetics. Emergent drugs (lesinurad, peglotidase) were found to be more effective for the acute management of refractory hyperuricemia, but their use is supported by a relatively small number of clinical trials so that further well-designed clinical research is needed to deepen their efficacy and safety profile.

Tumour lysis syndrome in patients with chronic lymphocytic leukaemia treated with BCL-2 inhibitors: risk factors, prophylaxis, and treatment recommendations

Tumour lysis syndrome is a complication of chemotherapy for haematological malignancies; in particular, aggressive leukaemias and lymphomas. For haematological malignancies, targeted therapies, such as small molecule inhibitors and monoclonal antibodies, have a high anti-tumour activity, are well tolerated, and have a low incidence of associated tumour lysis syndrome. The BCL-2 inhibitor venetoclax has a high anti-tumour activity in chronic lymphocytic leukaemia, achieving deep remissions by potently inducing apoptosis and increasing the risk for tumour lysis syndrome. In this Viewpoint, we discuss the pathophysiology, risk factors, monitoring, changes in laboratory parameters, and clinical manifestations of tumour lysis syndrome, and the prophylaxis and treatments available for this complication. Prophylaxis and treatment strategies have been implemented as standard of care in patients receiving venetoclax to minimise the risk of both laboratory and clinical manifestations of tumour lysis syndrome.

Cost-effectiveness analysis of rasburicase over standard of care for the prevention and treatment of tumor lysis syndrome in children with hematologic malignancies in China

Aims: To conduct a lifetime cost-effectiveness analysis (CEA) of rasburicase compared with standard of care (SOC) for tumor lysis syndrome (TLS) in children with hematologic malignancies from the Chinese healthcare system perspective. Materials and methods: The CEA was performed using a decision tree model with a lifetime horizon. The model explores the cost-effectiveness of rasburicase vs SOC for both preventing TLS and treating established TLS among pediatric patients with acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), and non-Hodgkin's lymphoma (NHL). Both the prophylaxis-use model and treatment-use model incorporate long-term health states of the diseases: survival without TLS and death. The efficacy data of rasburicase and SOC were obtained from published literature. Drug costs, healthcare resource utilization (HRU), and adverse event (AE) management costs were obtained via a published study with clinical experts. Costs in US dollar and quality-adjusted life year (QALY) are reported, and incremental cost-effectiveness ratios (ICERs) were also calculated. Uncertainties due to parameter fluctuations in the model were assessed through one-way sensitivity analysis and probabilistic sensitivity analysis (PSA). Results: During TLS prevention, compared with SOC, the ICER of rasburicase treatment in China are $17,580.04/QALY, $5,783.45/QALY, and $5,391.00/QALY for pediatric patients with AML, ALL, and NHL, respectively. For the established TLS treatment, compared with SOC, the ICERs of rasburicase treatment are $2,031.18/QALY, $1,142.93/QALY, and $990.37/QALY for pediatric patients with AML, ALL, and NHL, respectively. Limitations: The clinical data for SOC are based on the published study in China, and the rasburicase prevention or treatment failure rate was either calculated based on the risk ratio or directly from the clinical study among non-Chinese pediatric patients. Another study limitation was the lack of utility data for pediatric patients with TLS and without TLS. Thus, the utility scores of pediatric cancer survivors were used as an alternative. Conclusion: Rasburicase is estimated to be a cost-effective alternative to SOC in the prevention and treatment of TLS among Chinese pediatric patients with AML, ALL, and NHL.

[Effect of the Administration Period of Rasburicase in Japanese Adult Hematological Malignancy Patients at High-Risk for Tumor Lysis Syndrome]

Tumor lysis syndrome (TLS) is a life-threatening metabolic complication caused by the rapid breakdown of malignant cells. It is an oncologic emergency and occurs spontaneously after the initiation of chemotherapy for hematological malignancies. Therefore, the management of TLS is important. Rasburicase (RSB) has been shown to be effective for the management of TLS. We retrospectively investigated the optimal administration period of RSB (1 to 7 days) for 38 adult patients with a hematological malignancy who were at high risk for TLS. In all patients, the serum uric acid (sUA) value did not increase beyond the upper limit of normal. Clinical TLS did not occur in any patients. Seven patients were administered a single-dose of RSB and sUA remained within normal limits. These results suggested that single-dose RSB administration was efficacious for Japanese adult patients with hematological malignancies who are at high risk for TLS.

Urate oxidase for the prevention and treatment of tumour lysis syndrome in children with cancer

BACKGROUND

Tumour lysis syndrome (TLS) is a serious complication of malignancies and can result in renal failure or death. Previous reviews did not find clear evidence of benefit of urate oxidase in children with cancer. This review is the second update of a previously published Cochrane review.

OBJECTIVES

To assess the effects and safety of urate oxidase for the prevention and treatment of TLS in children with malignancies.

SEARCH METHODS

In March 2016 we searched CENTRAL, MEDLINE, Embase, and CINAHL. In addition, we searched the reference lists of all identified relevant papers, trials registers and other databases. We also screened conference proceedings and we contacted experts in the field and the manufacturer of rasburicase, Sanofi-aventis.

SELECTION CRITERIA

Randomised controlled trials (RCT) and controlled clinical trials (CCT) of urate oxidase for the prevention or treatment of TLS in children under 18 years with any malignancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted trial data and assessed individual trial quality. We used risk ratios (RR) for dichotomous data and mean difference (MD) for continuous data.

MAIN RESULTS

We included seven trials, involving 471 participants in the treatment groups and 603 participants in the control groups. No new studies were identified in the update. One RCT and five CCTs compared urate oxidase and allopurinol. Three trials tested Uricozyme, and three trials tested rasburicase for the prevention of TLS.The RCT did not evaluate the primary outcome (incidence of clinical TLS). It showed no clear evidence of a difference in mortality (both all-cause mortality (Fisher's exact test P = 0.23) and mortality due to TLS (no deaths in either group)), renal failure (Fisher's exact test P = 0.46), and adverse effects between the treatment and the control groups (Fisher's exact test P = 1.0). The frequency of normalisation of uric acid at four hours (10 out of 10 participants in the treatment group versus zero out of nine participants in the control group, Fisher's exact test P < 0.001) and area under the curve of uric acid at four days (MD -201.00 mg/dLhr, 95% CI -258.05 mg/dLhr to -143.95 mg/dLhr; P < 0.00001) were significantly better in the treatment group.One CCT evaluated the primary outcome; no clear evidence of a difference was identified between the treatment and the control groups (RR 0.77, 95% CI 0.44 to 1.33; P = 0.34). Pooled results of three CCTs showed significantly lower mortality due to TLS in the treatment group (RR 0.05, 95% CI 0.00 to 0.89; P = 0.04); no clear evidence of a difference in all-cause mortality was identified between the groups (RR 0.19, 95% CI 0.01 to 3.42; P = 0.26). Pooled results from five CCTs showed significantly lower incidence of renal failure in the treatment group (RR 0.26, 95% CI 0.08 to 0.89; P = 0.03). Results of CCTs also showed significantly lower uric acid in the treatment group at two days (three CCTs: MD -3.80 mg/dL, 95% CI -7.37 mg/dL to -0.24 mg/dL; P = 0.04), three days (two CCTs: MD -3.13 mg/dL, 95% CI -6.12 mg/dL to -0.14 mg/dL; P = 0.04), four days (two CCTs: MD -4.60 mg/dL, 95% CI -6.39 mg/dL to -2.81 mg/dL; P < 0.00001), and seven days (one CCT: MD -1.74 mg/dL, 95% CI -3.01 mg/dL to -0.47 mg/dL; P = 0.007) after therapy, but not one day (three CCTs: MD -3.00 mg/dL, 95% CI -7.61 mg/dL to 1.60 mg/dL; P = 0.2), five days (one CCT: MD -1.02 mg/dL, 95% CI -2.24 mg/dL to 0.20 mg/dL; P = 0.1), and 12 days (one CCT: MD -0.80 mg/dL, 95% CI -2.51 mg/dL to 0.91 mg/dL; P = 0.36) after therapy. Pooled results from three CCTs showed higher frequency of adverse effects in participants who received urate oxidase (RR 9.10, 95% CI 1.29 to 64.00; P = 0.03).Another included RCT, with 30 participants, compared different doses of rasburicase (0.2 mg/kg versus 0.15 mg/kg). The primary outcome was not evaluated. No clear evidence of a difference in mortality (all-cause mortality (Fisher's exact test P = 1.0) and mortality due to TLS (no deaths in both groups)) and renal failure (no renal failure in both groups) was identified. It demonstrated no clear evidence of a difference in uric acid normalisation (RR 1.07, 95% CI 0.89 to 1.28; P = 0.49) and uric acid level at four hours (MD 8.10%, 95% CI -0.99% to 17.19%; P = 0.08). Common adverse events of urate oxidase included hypersensitivity, haemolysis, and anaemia, but no clear evidence of a difference between treatment groups was identified (RR 0.54, 95% CI 0.12 to 2.48; P = 0.42).The quality of evidence ranks from very low to low because of imprecise results, and all included trials were highly susceptible to biases.

AUTHORS' CONCLUSIONS

Although urate oxidase might be effective in reducing serum uric acid, it is unclear whether it reduces clinical TLS, renal failure, or mortality. Adverse effects might be more common for urate oxidase compared with allopurinol. Clinicians should weigh the potential benefits of reducing uric acid and uncertain benefits of preventing mortality or renal failure from TLS against the potential risk of adverse effects.

Rasburicase for the Management of Tumor Lysis Syndrome in Neonates

Objective:

TO describe the management of tumor lysis syndrome (TLS) with rasburicase in 2 patients who presented with cancer within the first month of life and compare and contrast both cases with respect to their underlying renal physiology, management, and eventual outcome.

Case Summary:

TLS developed in 2 neonates born at 38 weeks' gestational age; both were managed in part with rasburicase. One patient was a 21 -day-old infant who received 2 days of induction chemotherapy for the treatment of congenital Stage IV-S neuroblastoma. With a single 0.2 mg/kg dose of rasburicase, the serum urate level normalized and the infant completed therapy without incident. The second patient was a 4-day-old neonate with congenital precursor-B cell acute lymphoblastic leukemia who presented with spontaneous TLS complicated by renal dysfunction. Despite several doses of intravenous rasburicase (2 doses of 0.1 mg/kg and 4 doses of 0.2 mg/kg), as well as aggressive supportive therapy, the infant died of complications arising from uncontrolled TLS.

Discussion:

Neonates may be at particular risk for TLS given their immature renal function and its predisposition toward metabolic derangements. While rasburicase has the potential to provide a rapid reversal of TLS in this patient population, when TLS is complicated by pre-existing acute renal failure, additional interventions and alternative anti-tumor strategies may be necessary for a successful outcome. When managing TLS in infancy, clinicians must consider the relative degree of renal immaturity and its predisposition toward metabolic derangements.

Conclusions:

Rasburicase appears to be well tolerated and effective in lowering serum urate concentrations in the treatment of therapy-related TLS in neonates. However, in instances of spontaneous TLS complicated by the normally low glomerular filtration rate in the newborn infant, the use of rasburicase and other supportive care measures may still be inadequate, warranting further study.

[Incidence and Risk Assessment of Tumor Lysis Syndrome in Patients with Advanced Germ Cell Cancer]

Tumor lysis syndrome (TLS) is a major oncological emergency. TLS is common in patients with hematological malignancies, but it can occur across a spectrum of cancer types. Germ cell tumors (GCT) have rapid cancer cell turnover and often present with bulky metastasis. The international TLS expert consensus panel has recommended guidelines for a medical decision tree to assign low, intermediate and high risk to patients with cancer at risk for TLS. GCT is classified as intermediate risk for TLS, and the patients who have other TLS risks factors are classified to be at high risk for TLS. In this study, we retrospectively analyzed 67 patients with metastatic GCT who were treated with induction chemotherapy at Tsukuba University Hospital between 2000 and 2013. Thirty-one, 15 and 21 patients were classified with good-, intermediate- and poor-prognosis disease, respectively, according to the International Germ Cell Cancer Collaborative Group criteria. Twelve patients (18%) were classified to be at high risk for TLS, and two patients were treated with allopurinol or rasburicase as prophylaxes for TLS. They did not show progression to laboratory TLS (L-TLS). In the remaining 10 TLS high-risk patients, three (30%) patients developed L-TLS after chemotherapy and started receiving oral allopurinol. As a result, no patients developed clinical TLS (C-TLS). In this study, 30% of TLS-high risk patients developed L-TLS without prophylactic treatment. Therefore, it is important to conduct TLS-risk stratification and consider prophylaxis such as rasburicase for advanced GCT patients at induction chemotherapy.

[Acute renal failure in patients with tumour lysis sindrome]

`Hematologic malignancies (leukemia, lymphoma, multiple myeloma, et al.), as well as solid tumours (renal, liver, lung, ovarian, etc.), can lead to acute or chronic renal failure.The most common clinical manifestation is acute renal failure within the tumour lysis syndrome (TLS). It is characterized by specific laboratory and clinical criteria in order to prove that kidney disorders result from cytolysis of tumour cells after chemotherapy regimen given, although on significantly fewer occasions it is likely to occur spontaneously or after radiotherapy. Essentially, failure is the disorder of functionally conserved kidney or of kidney with varying degrees of renal insufficiency, which render the kidney impaired and unable to effectively eliminate the end products of massive cytolysis and to correct the resulting disorders: hyperuricemia, hyperkalemia, hypocalcaemia, hyperphosphatemia, and others. The risk of TLS depends on tumour size, proliferative potential of malignant cells, renal function and the presence of accompanying diseases and disorders. Hydration providing adequate diuresis and administration of urinary suppressants (allopurinol, febuxostat) significantly reduce the risk of developing TLS. If prevention of renal impairment isn't possible, the treatment should be supplemented with hemodynamic monitoring and pharmacological support, with the possible application of recombinant urate-oxidase enzyme (rasburicase). Depending on the severity of azotemia and hydroelectrolytic disorders, application of some of the methods of renal replacement therapy may be considered.

[Acute Hyperuricemia and Kidney Injury after Three Cycles of Dose-Dense Chemotherapy for Retroperitoneal Choriocarcinoma -- A Case Report]

A 32 year-old man was diagnosed with retroperitoneal choriocarcinoma with metastasis to the lungs and liver. One cycle of modified BEP regimen did not sufficiently decrease the hCG. Therefore, we chose the GETUG 13 protocol of dose dense chemotherapy. After 6 days of cisplatin administration(3 cycles), he was diagnosed with acute hyperuricemia and kidney injury. He was treated with intravenous hydration and rasburicase. The hyperuricemia improved after a few days.

Pathogenesis and Clinical Management of Gouty Arthritis

Gout, the most common of the crystal arthritides is a result of disturbed uric acid metabolism and precipitation of urate crystals in extra cellular space of joints, periarticular tissue, bones and other organs. In the West, gout affects around 1% of adult men over 45 years of age. The estimated incidence being 0.6 to 2.1 per 1000 per year, with a prevalence of 9.5 to 13.5 per 1000 persons of all ages.1 The incidence of gout has been on rise globally; potentially attributable to recent shifts in diet, lifestyle, medical care, and increased longevity.2 Gout is three to four times more common in males than in pre-menopausal females; incidence in women increases after menopause and after the age of 60, approaches that in men.3 This update aims to highlight recent developments in understanding pathogenesis of gout along with current management strategies.

Interventions for tophi in gout

BACKGROUND

Tophi develop in untreated or uncontrolled gout. Their presence can lead to severe and potentially fatal complications. To date there have been no systematic reviews focused on the management of tophi in gout.

OBJECTIVES

To assess the benefits and harms of non-surgical and surgical treatments for the management of tophi in gout.

SEARCH METHODS

We searched three databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE. We handsearched American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts from 2010 to 2011, references from included studies and trial registries. We completed the most recent search on 20 May 2013.

SELECTION CRITERIA

All published randomised controlled trials (RCTs) or controlled clinical trials with quasi-randomised methods of allocating participants to treatment examining interventions for tophi in gout in adults. Possible interventions included urate-lowering pharmacological treatment (e.g. benzbromarone, probenecid, allopurinol, febuxostat, pegloticase), surgical removal or other interventions such as haemodialysis.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data from titles, abstracts and selected studies for detailed review, and extracted data and risk of bias independently. Major outcomes were number of participants with complete resolution of tophi, number of study participant withdrawals due to adverse events, joint pain reduction, function, quality of life, serum urate normalisation and total adverse events.

MAIN RESULTS

Only one study, at low risk of all biases, met the inclusion criteria. This was the pooled results from two RCTs (225 participants, 145 with tophi at baseline) randomised to one of three arms; pegloticase infusion every two weeks (biweekly), monthly pegloticase infusion (pegloticase infusion alternating with placebo infusion every two weeks) and placebo. Moderate-quality evidence from one study indicated that biweekly pegloticase 8 mg infusion reduced tophi in the subset of participants with tophi, but increased withdrawals due to adverse events in all participants, and monthly infusion appeared to result in less benefit.Biweekly pegloticase treatment resulted in resolution of tophi in 21/52 participants compared with 2/27 who received placebo (risk ratio (RR) 5.45, 95% confidence intervals (CI) 1.38 to 21.54; number needed to treat for an additional beneficial outcome (NNTB) 3 (95% CI 2 to 6).Eleven of 52 participants with monthly pegloticase treatment had complete resolution of one or more tophi compared with 2/27 who received placebo (RR 2.86, 95% CI 0.68 to 11.97).Participant-reported pain relief of 30% or greater, function, quality of life, serum urate normalisation, were reported for all participants but not separately for those with tophi; therefore, we did not include the results.Pegloticase administered biweekly resulted in more withdrawals due to adverse events compared with placebo (15/85 participants with pegloticase versus 1/43 participants with placebo; RR 7.59, 95% CI 1.04 to 55.55; number needed to treat for an additional harmful outcome (NNTH) 7, 95% CI 4 to 17). Pegloticase administered monthly also resulted in more withdrawals due to adverse events than placebo (16/84 participants with pegloticase versus 1/43 participants with placebo; RR 8.19, 95% CI 1.12 to 59.71; NNTH 6, 95% CI 4 to 14). Most withdrawals were due to infusion reactions.Total adverse events were high in all treatment groups: 80/85 participants administered pegloticase biweekly reported an adverse event compared with 41/43 from the placebo group (RR 0.99, 95% CI 0.91 to 1.07); 84/84 participants administered pegloticase monthly reported an adverse event versus 41/43 in the placebo group (RR 1.05, 95% CI 0.98 to 1.14). As 80% of adverse events were due to flares of gout, probably unrelated to the drug treatment per se, this may explain the high rate of adverse events in the placebo group - who were essentially untreated.

AUTHORS' CONCLUSIONS

This study showed pegloticase is probably beneficial in the management of tophi in gout, in terms of resolution of tophi, but with a high risk of adverse infusion reactions. However, there is a need for more RCT data considering other interventions, including surgical removal of tophi.

Urate oxidase for the prevention and treatment of tumour lysis syndrome in children with cancer

BACKGROUND

Tumour lysis syndrome (TLS) is a serious complication of malignancies and can result in renal failure or death. Preliminary reports suggest that urate oxidase is effective in reducing serum uric acid, the build-up of which causes TLS. It is uncertain whether high-quality evidence exists to support its routine use in children with malignancies.

OBJECTIVES

To assess the effects and safety of urate oxidase for the prevention and treatment of TLS in children with malignancies.

SEARCH METHODS

This is an update of the original review. We performed a comprehensive search of the Cochrane Central Register of Controlled Trials (CENTRAL) (in The Cochrane Library issue 1, 2013), MEDLINE (1966 to February 2013), Embase (1980 to February 2013), and CINAHL (1982 to February 2013). In addition, we searched the reference lists of all identified relevant papers. We also explored other internet sources (updated search on 26 February 2013): the NHS' National Research Register, the US National Institutes of Health Ongoing Trials Register, the metaRegister of Controlled Trials, and ProQuest Dissertations & Theses Database. We also screened conference proceedings of the American Society of Clinical Oncology, the European Society for Medical Oncology, and the International Society of Paediatric Oncology meetings from 1993 to 2012. Finally, we contacted experts in the field and the manufacturer of rasburicase, Sanofi-aventis.

SELECTION CRITERIA

Randomised controlled trials (RCT) and controlled clinical trials (CCT) of urate oxidase for the prevention or treatment of TLS in children under 18 years with any malignancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted trial data and assessed individual trial quality. We used risk ratios (RR) for dichotomous data and mean difference (MD) for continuous data.

MAIN RESULTS

We included seven trials, involving 471 participants in the treatment groups and 603 participants in the control groups. One RCT and five CCTs compared urate oxidase and allopurinol. Three trials tested Uricozyme, and three trials tested rasburicase for the prevention of TLS.The RCT showed no significant difference in mortality (both all-cause mortality and mortality due to TLS), renal failure, and adverse effects between the treatment and the control groups. The frequency of normalisation of uric acid at four hours (Fisher's exact test P < 0.001) and area under curve of uric acid at four days (MD -201.00 mg/dLhr, 95% confidence interval (CI) -258.05 mg/dLhr to -143.95 mg/dLhr; P < 0.00001) were significantly better in the treatment group. The trial did not evaluate the primary outcome (incidence of clinical TLS).Pooled results of three CCTs showed significantly lower mortality due to TLS in the treatment group (RR 0.05, 95% CI 0.00 to 0.89; P = 0.04); all-cause mortality was not significantly different between the groups. Pooled results from five CCTs showed significantly lower incidence of renal failure in the treatment group (RR 0.26, 95% CI 0.08 to 0.89; P = 0.03). Results of CCTs also showed significantly lower uric acid in the treatment group at two days (three CCTs), three days (two CCTs), four days (two CCTs), and seven days (one CCT) after therapy, but not one day (three CCTs), five days (one CCT), and 12 days (one CCT) after therapy. Pooled results from three CCTs showed higher frequency of adverse effects in participants who received urate oxidase (RR 9.10, 95% CI 1.29 to 64.00; P = 0.03). One CCT evaluated the primary outcome; no significant difference was identified.Another included RCT, with 30 participants, compared different doses of rasburicase (0.2 mg/kg versus 0.15 mg/kg), which demonstrated no significant difference in uric acid normalisation and uric acid level at four hours). Common adverse events of urate oxidase included hypersensitivity, haemolysis, and anaemia, but no significant difference between treatment groups was identified. No significant difference in mortality (all-cause mortality and mortality due to TLS) and renal failure was identified. The primary outcome was not evaluated.All included trials were highly susceptible to biases.

AUTHORS' CONCLUSIONS

Although urate oxidase might be effective in reducing serum uric acid, it is unclear whether it reduces clinical tumour lysis syndrome, renal failure, or mortality. Adverse effects might be more common for urate oxidase compared with allopurinol. Clinicians should weigh the potential benefits of reducing uric acid and uncertain benefits of preventing mortality or renal failure from TLS against the potential risk of adverse effects.

Urate oxidase for the prevention and treatment of tumour lysis syndrome in children with cancer

BACKGROUND

Tumour lysis syndrome (TLS) is a serious complication of malignancies and can result in renal failure or death. Preliminary reports suggest that urate oxidase is effective in reducing serum uric acid, the build-up of which causes TLS. It is uncertain whether high-quality evidence exists to support its routine use in children with malignancies.

OBJECTIVES

To assess the effects and safety of urate oxidase for the prevention and treatment of TLS in children with malignancies.

SEARCH METHODS

This is an update of the original review. We performed a comprehensive search of the Cochrane Central Register of Controlled Trials (CENTRAL) (in The Cochrane Library issue 1, 2013), MEDLINE (1966 to February 2013), Embase (1980 to February 2013), and CINAHL (1982 to February 2013). In addition, we searched the reference lists of all identified relevant papers. We also explored other internet sources (updated search on 26 February 2013): the NHS' National Research Register, the US National Institutes of Health Ongoing Trials Register, the metaRegister of Controlled Trials, and ProQuest Dissertations & Theses Database. We also screened conference proceedings of the American Society of Clinical Oncology, the European Society for Medical Oncology, and the International Society of Paediatric Oncology meetings from 1993 to 2012. Finally, we contacted experts in the field and the manufacturer of rasburicase, Sanofi-aventis.

SELECTION CRITERIA

Randomised controlled trials (RCT) and controlled clinical trials (CCT) of urate oxidase for the prevention or treatment of TLS in children under 18 years with any malignancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted trial data and assessed individual trial quality. We used risk ratios (RR) for dichotomous data and mean difference (MD) for continuous data.

MAIN RESULTS

We included seven trials, involving 471 participants in the treatment groups and 603 participants in the control groups. One RCT and five CCTs compared urate oxidase and allopurinol. Three trials tested Uricozyme, and three trials tested rasburicase for the prevention of TLS.The RCT showed no significant difference in mortality (both all-cause mortality and mortality due to TLS), renal failure, and adverse effects between the treatment and the control groups. The frequency of normalisation of uric acid at four hours (Fisher's exact test P < 0.001) and area under curve of uric acid at four days (MD -201.00 mg/dLhr, 95% confidence interval (CI) -258.05 mg/dLhr to -143.95 mg/dLhr; P < 0.00001) were significantly better in the treatment group. The trial did not evaluate the primary outcome (incidence of clinical TLS).Pooled results of three CCTs showed significantly lower mortality due to TLS in the treatment group (RR 0.05, 95% CI 0.00 to 0.89; P = 0.04); all-cause mortality was not significantly different between the groups. Pooled results from five CCTs showed significantly lower incidence of renal failure in the treatment group (RR 0.26, 95% CI 0.08 to 0.89; P = 0.03). Results of CCTs also showed significantly lower uric acid in the treatment group at two days (three CCTs), three days (two CCTs), four days (two CCTs), and seven days (one CCT) after therapy, but not one day (three CCTs), five days (one CCT), and 12 days (one CCT) after therapy. Pooled results from three CCTs showed higher frequency of adverse effects in participants who received urate oxidase (RR 9.10, 95% CI 1.29 to 64.00; P = 0.03). One CCT evaluated the primary outcome; no significant difference was identified.Another included RCT, with 30 participants, compared different doses of rasburicase (0.2 mg/kg versus 0.15 mg/kg), which demonstrated no significant difference in uric acid normalisation and uric acid level at four hours). Common adverse events of urate oxidase included hypersensitivity, haemolysis, and anaemia, but no significant difference between treatment groups was identified. No significant difference in mortality (all-cause mortality and mortality due to TLS) and renal failure was identified. The primary outcome was not evaluated.All included trials were highly susceptible to biases.

AUTHORS' CONCLUSIONS

Although urate oxidase might be effective in reducing serum uric acid, it is unclear whether it reduces clinical tumour lysis syndrome, renal failure, or mortality. Adverse effects might be more common for urate oxidase compared with allopurinol. Clinicians should weigh the potential benefits of reducing uric acid and uncertain benefits of preventing mortality or renal failure from TLS against the potential risk of adverse effects.

Pegloticase for treatment of tophaceous polyarticular gout

This is a case report of a patient with treatment resistant gout who was prescribed pegloticase and developed a severe reaction. A 30-year-old Hawaiian-Filipino man presented with a nine-year history of gout that progressed from episodic monoarticular arthritis, treated with aspiration and corticosteroid injections, to more aggressive disease with more frequent attacks requiring escalation of therapy. He was treated with systemic corticosteroids, colchicine and nonsteroidal anti-inflammatory drugs, but then required allopurinol. Despite aggressive therapy, the patient continued to have hyperuricemia and tophi developed even after treatment with febuxostat and probenicid. The patient became wheel chair bound due to his pain and, at that point, the decision was made to initiate treatment with pegloticase. The patient initially experienced significant improvement with treatment; however, he soon began to have elevation in his serum uric acid levels and developed a severe reaction during treatment.

Pre-treatment with allopurinol or uricase attenuates barrier dysfunction but not inflammation during murine ventilator-induced lung injury

Introduction

Uric acid released from injured tissue is considered a major endogenous danger signal and local instillation of uric acid crystals induces acute lung inflammation via activation of the NLRP3 inflammasome. Ventilator-induced lung injury (VILI) is mediated by the NLRP3 inflammasome and increased uric acid levels in lung lavage fluid are reported. We studied levels in human lung injury and the contribution of uric acid in experimental VILI.

Methods

Uric acid levels in lung lavage fluid of patients with acute lung injury (ALI) were determined. In a different cohort of cardiac surgery patients, uric acid levels were correlated with pulmonary leakage index. In a mouse model of VILI the effect of allopurinol (inhibits uric acid synthesis) and uricase (degrades uric acid) pre-treatment on neutrophil influx, up-regulation of adhesion molecules, pulmonary and systemic cytokine levels, lung pathology, and regulation of receptors involved in the recognition of uric acid was studied. In addition, total protein and immunoglobulin M in lung lavage fluid and pulmonary wet/dry ratios were measured as markers of alveolar barrier dysfunction.

Results

Uric acid levels increased in ALI patients. In cardiac surgery patients, elevated levels correlated significantly with the pulmonary leakage index. Allopurinol or uricase treatment did not reduce ventilator-induced inflammation, IκB-α degradation, or up-regulation of NLRP3, Toll-like receptor 2, and Toll-like receptor 4 gene expression in mice. Alveolar barrier dysfunction was attenuated which was most pronounced in mice pre-treated with allopurinol: both treatment strategies reduced wet/dry ratio, allopurinol also lowered total protein and immunoglobulin M levels.

Conclusions

Local uric acid levels increase in patients with ALI. In mice, allopurinol and uricase attenuate ventilator-induced alveolar barrier dysfunction.

Economic implications of rasburicase treatment in adult patients with tumour lysis syndrome

BACKGROUND

Rasburicase is a recombinant urate-oxidase enzyme used to reduce high levels of plasma uric acid (PUA) resulting from tumour lysis syndrome (TLS). Rasburicase reduces PUA levels within 4 hours of administration, thereby minimizing the risk of serious complications from TLS. Treatment pattern analyses indicate rasburicase is often used in combination with allopurinol; however, no studies have evaluated the clinical and economic consequences of this pattern of care. The purpose of this study was to compare hospitalization costs, overall length of stay (LOS), and critical-care LOS in patients receiving rasburicase with or without allopurinol.

METHODS

Hospital claims data from the Premier Perspective Database™ were used to conduct this retrospective analysis. Patients in the Premier hospital database who were administered rasburicase or combination therapy (rasburicase + allopurinol) within 2 days of hospital admission were eligible for study inclusion. Patients were excluded if they were <18 years of age or received haemodialysis (or any other renal replacement therapy support) on admission. Rasburicase patients were propensity-score-matched to combination therapy patients based on gender, race, hospital type (urban/rural, teaching), provider type, payer type, admission source, use of electrolyte modification therapy, critical-care admission and presence of a cancer diagnosis. Differences in healthcare costs, overall LOS and critical-care LOS were assessed using γ-distributed generalized linear models with a log-link function.

RESULTS

The study population comprised 66 patients receiving rasburicase monotherapy matched to 66 patients receiving combination therapy. Mean age was 62.9 years, and 29% were female. Patients initiated on combination therapy had a shorter mean duration of rasburicase administration than patients initiated on monotherapy (2.1 vs 2.7 days) [p = 0.0059]. Additionally, rasburicase monotherapy incurred an average total cost of $US35 843 per hospitalization, compared with $US46 672 for those receiving combination therapy (p = 0.0820). Rasburicase monotherapy patients also had a shorter mean overall LOS (10.0 days vs 15.4 days; p = 0.0067). The mean critical-care LOS was similar in both cohorts (2.4 days rasburicase vs 2.9 days combination therapy; p = 0.3389).

CONCLUSION

Examination of claims data showed that combination therapy (rasburicase + allopurinol) trended toward higher total hospitalization costs than rasburicase monotherapy. In addition, combination therapy was associated with significantly longer overall LOS compared with upfront rasburicase monotherapy in patients at risk for developing TLS.

A patient with tumor lysis syndrome

When caring for a patient with TLS, astute nursing care is required for positive patient outcomes. Assessments and monitoring are required for prompt management of complications and patient safety. Because of the skilled nursing care that Mr. B received, along with supportive medications and hydration, his renal function improved, with increased urine output, normalization of electrolytes, and return of his appetite.

Recent advances in management of gout

Incidence and prevalence of gout have markedly increased over the last few decades in keeping with the rise in prevalence of obesity and metabolic syndrome. Until recently, management of gout in patients with associated metabolic syndrome and comorbid illnesses such as renal impairment was difficult because of limited treatment options. However, significant progress has been made in the last few years, with introduction of new treatments such as interleukin-1 antagonists for management of acute gout, and febuxostat and pegloticase for chronic gout. The association of gout with alcohol, dietary purines and fructose ingestion has been confirmed in large prospective studies, thus enabling the clinician to now provide evidence-based advice to patients. Recent efficacy and safety data favour lower over higher doses of colchicine, and oral corticosteroids over non-steroidal anti-inflammatory drugs for patients with acute gout. Local ice therapy might help to differentiate gout from other forms of inflammatory arthritis, and supplementation with vitamin C help to reduce risk of gout. Several other drugs with rational mechanisms of action are in the pipeline, and likely to be introduced over the next few years. A new era has thus begun in the field of gout.

Rasburicase for hyperuricemia in hemolytic uremic syndrome

BACKGROUND

Acute kidney injury (AKI) with elevated serum uric acid (UA) levels has been reported in patients with hemolytic uremic syndrome (HUS). AKI is thought to result from tubular obstruction by UA crystals. Inducing a diuresis may ameliorate the oligoanuria in such patients. We describe a child with HUS in whom reducing UA with fluids and rasburicase appeared to accelerate the recovery of renal function.

CASE-DIAGNOSIS/TREATMENT

A 9-month-old Caucasian male infant presented with 6 days of diarrhea, 3 days of vomiting, and 24 h of oliguria. On admission, hemoglobin was 8.3 g/dL, platelet count 36,000/L, blood urea nitrogen 73 mg/dL, and serum creatinine (SCr) 2.7 mg/dL. Diarrhea-associated HUS was diagnosed. The day after admission, SCr was 2.9 mg/dL and UA 12.3 mg/dL. On hospital day 2, he received a dose of intravenous rasburicase 0.18 mg/kg, and less than 12 h later, the UA had fallen to 0.3 mg/dL. The SCr level also started to fall, and urine output progressively increased without the use of diuretics. Renal function continued to improve, and the UA level remained normal despite ongoing hemolysis requiring a second red blood cell transfusion on hospital day 5. The patient was discharged on hospital day 7 in good physical condition. Two months later, he was in good health, with a SCr level of 0.2 mg/dL and UA of 4.2 mg/dL.

CONCLUSIONS

We postulate that aggressive management of the high serum UA level with rasburicase and fluid hydration accelerated the recovery of our patient. Further studies are needed to determine the role of rasburicase in the treatment of hyperuricemia in patients with HUS.

Rasburicase for huge hepatocellular carcinoma with tumor lysis syndrome: case report

OBJECTIVE

To report a case of huge hepatocellular carcinoma associated with tumor lysis syndrome and its management.

CLINICAL PRESENTATION AND INTERVENTION

A 51-year-old hepatitis B carrier visited our clinic with progressive weight loss over recent months. Abdominal ultrasonography and magnetic resonance imaging revealed a huge hepatic mass in a cirrhotic liver, identified as hepatocellular carcinoma. A hepatologist and surgeon recommended transarterial chemoembolization followed by hepatectomy. The patient underwent the procedure, with the complication of tumor lysis syndrome. He was treated with a single high dose (9 mg) of rasburicase and his clinical condition improved dramatically, with acute kidney injury subsiding without emergent hemodialysis.

CONCLUSIONS

This was a case of hepatocellular carcinoma with tumor lysis syndrome and acute kidney injury, treated successfully with rasburicase.

Single dose of rasburicase for treatment of hyperuricemia in acute kidney injury: a report of 3 cases

Severe hyperuricemia accompanied by the other comorbidities such as anuria, fluid overload, calcium-phosphate imbalance, and/or tumor lysis syndrome is one of the indications for dialysis in the setting of acute kidney injury. Rasburicase is used in different clinical conditions such as tumor lysis syndrome and uric acid nephropathy. Among referred patients to our center from 2008 to 2010, there were 3 patients who had an indication for dialysis because of hyperuricemia. Contributing factors to the acute kidney injury were multi-organ dysfunction, rapidly progressive glomerulonephritis, and spontaneous tumor lysis syndrome. None of the patients showed any response to treatment with bicarbonate and hydration. After rasburicase administration, serum uric acid level declined, and urine output increased. Treatment with a single low dose of rasburicase would be effective to decrease the serum uric acid level and reverse kidney injury secondary to uric acid nephropathy.

Metastatic gestational trophoblastic neoplasia complicated by tumor lysis syndrome, heart failure, and thyrotoxicosis: a case report

BACKGROUND

Tumor lysis syndrome (TLS) is an extremely rare complication of solid tumors and is more frequently observed in patients with hematologic malignancies. This report describes a novel approach to the management of a rare case of TLS in metastatic gestational trophoblastic neoplasia (GTN).

CASE

A 17-year-old female presented 8 weeks postpartum with severe anemia, thyrotoxicosis, and elevated serum beta-human chorionic gonadotropin (beta-hCG). Imaging studies confirmed metastatic GTN to the lungs. The patient developed grade 4 TLS after the first cycle of etoposide, methotrexate, dactinomycin, cyclophosphamide, and vincristine (EMA-CO). She did not respond to standard treatment of aggressive hydration and allupurinol and continued to be in renal failure with elevated uric acid. A single dose of recombinant urate oxidase, rasburicase, rendered the uric acid level undetectable in 3 days and completely reversed the renal failure, avoiding hemodialysis. Three more cycles of EMA-CO were then administered. Subsequently, the patient developed congestive heart failure and was switched to single-agent actinomycin-D. Beta-hCG became negative after 5 cycles, and her ejection fraction returned to baseline.

CONCLUSION

This is a rare case of TLS in the setting of metastatic GTN. To our knowledge this is the first reported case of utilizing rasburicase for the management of TLS in GTN.