A review of tumour lysis syndrome with targeted therapies and the role of rasburicase

Tumor Lysis Syndrome in a Patient with BRAFV600E Mutated Colon Cancer Treated with Cetuximab and Encorafenib

Tumor lysis syndrome (TLS) is a fatal complication associated with chemotherapy. We herein report a case of TLS in a 73-year-old woman with metastatic BRAFV600E mutated colon cancer after she received combined treatment with cetuximab and encorafenib. The serum uric acid, urea nitrogen, and creatinine levels were elevated on day four of the first cycle. The fibrin degradation product (FDP) and D-dimer levels were also high. Diuresis and rasburicase were initiated for TLS, and the laboratory data all normalized on day 8. Thus, the possibility of TLS being induced by targeted drugs in patients with solid tumors, including colorectal cancer, must not be overlooked.

Unraveling proton-coupled electron transfer in cofactor-free oxidase- and oxygenase-catalyzed oxygen activation: a theoretical view

Oxygen plays a crucial role in the metabolic processes of non-anaerobic organisms. However, a detailed understanding of how triplet oxygen participates in the enzymatic oxidation of organic compounds involved in life processes is still lacking. It is noteworthy that recent studies have found that cofactor-free oxidase- and oxygenase-catalyzed oxygen activation occurs through proton-coupled electron transfer (PCET), which is significantly different from the previously proposed single electron transfer (SET) mechanism. Herein, we summarize the recent advances in the general mechanism of catalytic activation reactions of triplet oxygen by these enzymes. We believe that this review not only helps in providing a deep understanding of the processes involved in oxygen metabolism in organisms but also provides valuable theoretical reference data for designing more efficient enzyme mutants for treating diseases and handling environmental pollution in the future.

Important Considerations in the Intensive Care Management of Acute Leukemias

In the realm of hematologic disorders, acute leukemia is approached as an emergent disease given the multitude of complications and challenges that present both as a result of inherent disease pathology and adverse events associated with antineoplastic therapies and interventions. The heavy burden of leukemic cells may lead to complications including tumor lysis syndrome, hyperleukocytosis, leukostasis, and differentiation syndrome, and the initiation of treatment can further exacerbate these effects. Capillary leak syndrome is observed as a result of antineoplastic agents used in acute leukemia, and L-asparaginase, a bacterial-derived enzyme, has a unique side effect profile including association with thrombosis. Thrombohemorrhagic syndrome and malignancy-associated thrombosis are also commonly observed complications due to direct disequilibrium in coagulant and anticoagulant factors. Due to inherent effects on the white blood cell milieu, leukemia patients are inherently immunocompromised and vulnerable to life-threatening sepsis. Lastly, the advents of newer therapies such as chimeric antigen receptor (CAR) T-cells have clinicians facing the management of related toxicities on unfamiliar territory. This review aims to discuss these acute leukemia-associated complications, their pathology, and management recommendations.

Rasburicase in treating tumor lysis syndrome: An umbrella review

Tumor lysis syndrome (TLS) remains a debilitating cause of hospitalization and death in patients with cancer and is a significant challenge for healthcare providers despite advancements in its management. This umbrella review analyzed the results of meta-analyses on the use of rasburicase in the treatment of patients with cancer. A literature search was performed of five databases (PubMed, Google Scholar, Cochrane Library, Scopus, Global Index Medicus, and ScienceDirect) for articles with full texts available online. A measurement tool to assess systematic reviews 2 (AMSTAR 2) was used to assess the quality of the included studies, and Review Manager software was used to conduct all statistical analyses. The systematic search identified eight relevant meta-analyses, with primary analyses including outcome data that analyzed mortality, renal failure, and comparisons with allopurinol. The pooled data showed that rasburicase effectively reduced TLS development and serum uric acid levels in children and adults with malignancies. Most outcomes did not differ significantly compared with those of allopurinol. Future trials should focus on the cost-effectiveness of rasburicase compared to that of allopurinol while including high-, intermediate-, and low-risk patients. Rasburicase is safe and effective for managing patients with TLS. However, recent large-scale meta-analyses have reported conflicting results. Most meta-analyses were graded as low to critically low as per AMSTAR 2. The analysis revealed that the benefit of rasburicase did not differ significantly from that of allopurinol, which has higher cost-effectiveness and fewer side effects.

Cofactor-Free Dioxygenases-Catalyzed Reaction Pathway via Proton-Coupled Electron Transfer

Understanding the general mechanism of the metal-free and cofactor-free oxidases and oxygenases catalyzed activation of triplet O₂ is one of the most challenging questions in the field of enzymatic catalysis. Herein, we have performed Quantum Mechanics/Molecular Mechanics (QM/MM) multiscale simulations to reveal the detailed mechanism of the HOD catalyzed (i.e., 1-H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase from Arthrobacter nitroguajacolicus Rü61a) decomposition of N-heteroaromatic compounds. The complete catalytic mechanism includes four steps: (1) proton transfer from 1-H-3-hydroxy-4-oxoquinaldine (QND) substrate to His251 residue coupled with an electron transfer from QND to triplet O₂ (i.e., PCET), (2) formation of C-O bond via an open-shell singlet diradical recombination pathway, (3) ring-closure to form a bicyclic ring, and (4) dissociation of CO. The dissociation of CO is determined as the rate-limiting step, and its calculated energy barrier of 14.9 kcal/mol is consistent with the 15.5 kcal/mol barrier derived from experimental kinetic data. The mechanistic profile is not only valuable for understanding the fundamental pathway of cofactor-free oxidases and oxygenases-catalyzed reactions involving the triplet O₂ activation but also discloses a new pathway that undergoes the processes of PCET and open-shell singlet transition state.

Leukoreductive response to the combination of sorafenib and chemotherapy in hyperleukocytosis of FLT3-ITD mutated pediatric AML

Twelve to 22% of pediatric acute myeloid leukemia (AML) patients present with hyperleukocytosis, which is one of the main risk factors of early death due to its clinical complications: leukostasis, causing pulmonary or central nervous system injuries, tumor lysis syndrome, and disseminated intravascular coagulation. Sorafenib is a multi-kinase inhibitor that blocks the Fms-Related Tyrosine Kinase 3 receptor (FLT3) in AML patients with a FLT3-internal tandem duplication (FLT3-ITD), leading to a reduction of proliferation. Here we report four de novo diagnosed or relapsed pediatric FLT3-ITD-positive AML patients with hyperleukocytosis, which were treated with sorafenib in combination with cytoreductive chemotherapy prior to the start of the induction phase. We observed a fast reduction of white blood cells in peripheral blood and bone marrow. This resulted in a rapid clinical stabilization of the patients. Adverse side effects-such as dermatologic toxicity, elevation of transaminases and hypertension-occurred but were mild and inductive chemotherapy could be started in parallel or subsequently. This implies sorafenib as a safe and effective treatment option in combination with chemotherapy during cytoreductive prephase for children with this life-threatening condition.

Arrhythmia in tumor lysis syndrome and associated in-hospital mortality: A nationwide inpatient analysis

BACKGROUND

Tumor lysis syndrome (TLS) is a life-threatening oncologic emergency associated with fatal complications including arrhythmia. The epidemiology and mortality outcomes of arrhythmia in TLS are scarcely studied in the literature.

METHODS

We used the National Inpatient Sample (NIS) to study the prevalence and outcome of arrhythmia in patients hospitalized with TLS (ICD-9 code 277.88) from 2009 to 2014. Baseline characteristics, burden of arrhythmia, and pertinent outcomes were analyzed. Multivariable regression analysis was performed to identify the impact of underlying malignancy in predicting TLS-related mortality.

RESULTS

A total of 9034 cases of arrhythmia among 37 861 TLS patients were identified. More than half of the arrhythmia cases (67%) were found among white old (>65) males admitted to large bed size and urban teaching hospitals. Arrhythmic cohort showed higher frequency of comorbidities such as fluid-electrolyte disturbances, hypertension, congestive heart failure, renal failure, dyslipidemia, diabetes, pulmonary circulatory disorders, chronic pulmonary disease, coagulopathy, and deficiency anemia. The most common malignancies were leukemia, lymphoma, metastatic tumor, and solid tumor without metastasis. We found significantly higher odds of in-hospital mortality among patients with TLS compared to general inpatient population on unadjusted (OR 9.69, 95% CI: 9.27-10.13, P < .001) and adjusted (OR 4.62, 95% CI: 4.39-4.85) multivariable analyses. Overall in-hospital mortality (32% vs 21.3%), median length of stay (11 days vs 9 days), and hospital charges were higher among arrhythmic than nonarrhythmic patients.

CONCLUSION

With the availability of more advanced cancer therapy in the US, nearly one in four inpatient encounters of TLS had arrhythmia. Arrhythmia in TLS patients was associated with higher odds of mortality and increased resource utilization. Therefore, strategies to improve the supportive care of TLS patients plus timely diagnosis and treatment of arrhythmia are of utmost importance in reducing mortality and health-care cost.

Ixazomib-associated tumor lysis syndrome in multiple myeloma: A case report

RATIONALE

Tumor lysis syndrome (TLS) is an oncologic emergency, but its incidence in MM is rare. To our knowledge, ixazomib has not been associated with TLS in MM.

PATIENT CONCERNS

The patient developed TLS after 10 days of treatment with ixazomib, accompanied by renal failure of hyperuricemia, hyperkalemia, and hyperphosphatemia.

DIAGNOSES

MM (type IgG λ) was diagnosed according to the diagnostic criteria established by the International Myeloma Working Group and classified stage IIA by the International Staging System. TLS was diagnosed after the patient met all three criteria of the Cairo-Bishop TLS scoring system.

INTERVENTIONS

From April 8, 2017, the patient was treated with 3 courses of bortezomib, cyclophosphamide, and dexamethasone chemotherapy. From August 18, she received five courses of bortezomib combined with DCEP chemotherapy. On May 21, 2018 treatment was switched to lenalidomide, bortezomib, and dexamethasone for four courses. Ixazomib was started on October 10, 2018 with cyclophosphamide and dexamethasone. On October 19, 2018 vigorous intravenous hydration with sodium bicarbonate was initiated and peroral febuxostat was administered.

OUTCOMES

On October 19, changes in hematological indicators raised concern for TLS worsening kidney function and decreasing urine output. She refused renal replacement treatment for TLS-induced acute kidney injury. On October 26th, the patient died of respiratory failure.

LESSONS

This case highlights the need to vigilant for the occurrence of TLS in patients undergoing MM treatment with ixazomib. Higher baseline uric acid or creatinine, rapidly progressive anemia, and raised lactate dehydrogenase (LDH) and β2-microglobulin may be surrogate markers of TLS.

Diagnosis and management of tumor lysis syndrome

Tumor lysis syndrome (TLS) is an oncological emergency characterized by a classic tetrad of hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia. Risk assessment and prophylactic therapy is critical in preventing this oncological emergency. Treatment of established TLS involves aggressive hydration, electrolyte management, and the use of hypouricemic agents.

Tumour lysis syndrome

Tumour lysis syndrome (TLS) is a life-threatening emergency characterised by a massive cytolysis with the release of intracellular electrolytes, nucleic acids, and metabolites into the circulation. TLS comprises laboratory derangements (hyperuricaemia, hyperkalaemia, hyperphosphataemia, and hypocalcaemia) responsible for acute kidney injury. In patients with hematologic malignancies after cytotoxic therapy or spontaneously and also in advanced solid tumours. Assessment of disease specific risk level for TLS in patients receiving anti-tumoural therapy is essential for early diagnosis. Prophylaxis is the mainstay of management of TLS. It is important to routinely initiate a risk-adapted prophylactic strategy to correct metabolic alterations and preserve renal function. High and intermediate risk patients and patients with established TLS should be managed with multidisciplinary medical care in a hospital unit to receive monitoring and medical care. Renal replacement therapy should be considered in patients with refractory TLS.

Tumor Lysis Syndrome

Tumor lysis syndrome (TLS) is an acute, life-threatening disease among adults and children that is associated with the initiation of cytoreductive therapy in the treatment of malignancy. A pattern of metabolic derangements occurs as a result of a massive release of intracellular contents into the systemic circulation. Characteristic findings include hyperuricemia, hyperphosphatemia, hyperkalemia, hypocalcemia, and uremia, all of which can lead to cardiac arrhythmia, seizures, renal failure, and sudden death. The incidence of TLS appears to be increasing because of a rapidly growing armamentarium of highly effective biologic and targeted therapies. Risk assessment and prevention are at the forefront of management and rely on clinician awareness, prophylactic measures, and vigilant laboratory monitoring. Established TLS requires early, aggressive intervention with intravenous hydration, electrolyte management, and the use of hypouricemic agents. This review highlights the central role of diagnostic laboratory criteria for TLS, and summarizes the clinical findings, pathophysiology, and evidence-based guidelines for the prevention and management of TLS.

Tumor Lysis Syndrome in Chronic Lymphocytic Leukemia with Novel Targeted Agents

Tumor lysis syndrome (TLS) is an uncommon but potentially life-threatening complication associated with the treatment of some cancers. If left untreated, TLS may result in acute renal failure, cardiac dysrhythmia, neurologic complications, seizures, or death. Tumor lysis syndrome is most commonly observed in patients with hematologic malignancies with a high proliferation rate undergoing treatment with very effective therapies. In chronic lymphocytic leukemia (CLL), historically, TLS has been observed less often, owing to a low proliferation rate and slow response to chemotherapy. New targeted therapies have recently been approved in the treatment of CLL, including the oral kinase inhibitors, idelalisib and ibrutinib, and the B-cell lymphoma-2 protein inhibitor, venetoclax. Several others are also under development, and combination strategies of these agents are being explored. This review examines the diagnosis, prevention, and management of TLS and summarizes the TLS experience in CLL clinical trials with newer targeted agents. Overall, the risk of TLS is small, but the consequences may be fatal; therefore, patients should be monitored carefully. Therapies capable of eliciting rapid response and combination regimens are increasingly being evaluated for treatment of CLL, which may pose a higher risk of TLS. For optimal management, patients at risk for TLS require prophylaxis and close monitoring with appropriate tests and appropriate management to correct laboratory abnormalities, which allows for safe and effective disease control.

IMPLICATIONS FOR PRACTICE

Tumor lysis syndrome (TLS) is a potentially fatal condition observed with hematologic malignancies, caused by release of cellular components in the bloodstream from rapidly dying tumor cells. The frequency and severity of TLS is partly dependent upon the biology of the disease and type of therapy administered. Novel targeted agents highly effective at inducing rapid cell death in chronic lymphocytic leukemia (CLL) may pose a risk for TLS in patients with tumors characterized by rapid growth, high tumor burden, and/or high sensitivity to treatment. In this review, prevention strategies and management of patients with CLL who develop TLS are described.

Drug-induced hyperuricaemia and gout

Hyperuricaemia is a common clinical condition that can be defined as a serum uric acid level >6.8 mg/dl (404 µmol/l). Gout, a recognized complication of hyperuricaemia, is the most common inflammatory arthritis in adults. Drug-induced hyperuricaemia and gout present an emergent and increasingly prevalent problem in clinical practice. Diuretics are one of the most important causes of secondary hyperuricaemia. Drugs raise serum uric acid level by an increase of uric acid reabsorption and/or decrease in uric acid secretion. Several drugs may also increase uric acid production. In this review, drugs leading to hyperuricaemia are summarized with regard to their mechanism of action and clinical significance. Increased awareness of drugs that can induce hyperuricaemia and gout, and monitoring and prevention are key elements for reducing the morbidity related to drug-induced hyperuricaemia and gout.

Catalytic Mechanisms for Cofactor-Free Oxidase-Catalyzed Reactions: Reaction Pathways of Uricase-Catalyzed Oxidation and Hydration of Uric Acid

First-principles quantum mechanical/molecular mechanical (QM/MM)-free energy calculations have been performed to uncover how uricase catalyzes metabolic reactions of uric acid (UA), demonstrating that the entire reaction process of UA in uricase consists of two stages-oxidation followed by hydration. The oxidation consists of four steps: (1) chemical transformation from 8-hydroxyxythine to an anionic radical via a proton transfer along with an electron transfer, which is different from the previously proposed electron-transfer mechanism that involves a dianion intermediate (UA^2-) during the catalytic reaction process; (2) proton transfer to the O₂^- anion (radical); (3) diradical recombination to form a peroxo intermediate; (4) dissociation of H₂O₂ to generate the dehydrourate. Hydration, for the most favorable pathway, is initiated by the nucleophilic attack of a water molecule on dehydrourate, along with a concerted proton transfer through residue Thr69 in the catalytic site. According to the calculated free energy profile, the hydration is the rate-determining step, and the corresponding free energy barrier of 16.2 kcal/mol is consistent with that derived from experimental kinetic data, suggesting that the computational insights into the catalytic mechanisms are reasonable. The mechanistic insights not only provide a mechanistic base for future rational design of uricase mutants with improved catalytic activity against uric acid as an improved enzyme therapy, but also are valuable for understanding a variety of other cofactor-free oxidase-catalyzed reactions involving an oxygen molecule.

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.

Rational use of rasburicase for the treatment and management of tumor lysis syndrome

Purpose There is a lack of high-level evidence identifying meaningful outcomes and the optimal place in therapy of rasburicase in patients with, or at high risk for tumor lysis syndrome. The primary objective of this study was to evaluate and characterize outcomes resulting from an institution-specific guideline emphasizing supportive care, xanthine oxidase inhibitors, and lower doses of rasburicase. Methods In this retrospective chart review, we compared conservative rasburicase dosing, in accordance with newly developed UMHS tumor lysis syndrome guidelines, with aggressive rasburicase in adult patients (≥ 18 years of age) with hematological or solid tumor malignancies, and a uric acid level between 8 and 15 mg/dL. The primary efficacy outcome assessed the difference in the proportion of patients achieving a uric acid level <8 mg/dL within 48 h using a one-sided noninferiority test. The principle safety outcomes analyzed included incidence of acute kidney injury and hemodialysis requirement. Results One hundred sixty-one patients met inclusion criteria and were included in the study. Within 48 h of an elevated uric acid level, treatment was successful in 97.03% of patients in the conservative group, as compared with 98.33% in the aggressive group (difference, 1.3 percentage points; 95% confidence interval [CI], -3.33 to 5.93). Furthermore, there was no difference in the proportion of patients requiring hemodialysis (2.97% vs. 10.0%, p-value 0.079), or incidence of acute kidney injury (4.0% vs. 12.5%, p-value 1.00) between the treatment group and control group, respectively. Conclusions Conservative rasburicase use was noninferior to aggressive rasburicase use in patients with or at high risk for tumor lysis syndrome.

Investigating Effects of Acidic pH on Proliferation, Invasion and Drug-Induced Apoptosis in Lymphoblastic Leukemia

Some studies have shown that extracellular pH in tumors, which results in tumor progression, is less than that in normal tissues. The aim of this study was to investigate the effects of extracellular acidic pH on proliferation, invasion, and drug-induced apoptosis in acute lymphoblastic cells. The cells were cultured in different pH (pH 6.6 and pH 7.4) for 12 days. Cell proliferation was assessed by MTT assay and cell invasion was assayed by invasion assay and gene expression analysis of MMP-9. Drug-induced apoptosis was evaluated after exposure to doxorubicin for 24 hours by annexin V/PI staining and gene expression analysis of BAX pro-apoptotic protein. The results indicated the enhanced growth and invasion of leukemic cells at pH 6.6 (P ≤ 0.05). Furthermore, the cells at pH 6.6 were resistant to apoptosis by doxorubicin (P ≤ 0.05). It can be concluded that acidic pH increases the proliferation, invasion and reduces the drug-induced apoptosis in acute lymphoblastic leukemia. Extracellular acidity can influence the behavior of leukemic cells and therefore, the manipulation of extracellular liquid can be selected as a therapeutic strategy for leukemia, especially for acute lymphoblastic leukemia.

Tumor lysis syndrome following trastuzumab and pertuzumab for metastatic breast cancer: a case report

Background

Tumor lysis syndrome is a rare and potentially fatal complication of oncologic treatments, especially in solid tumors. To the best of our knowledge, tumor lysis syndrome has never been reported after trastuzumab and pertuzumab combination therapy. Knowledge of risk factors and active prevention proceedings is of utmost importance to avoid fatal outcomes.

Case presentation

We present the case of a chemo-naive 58-year-old Belgian woman developing hypovolemic shock and multiple organ failure due to tumor lysis syndrome after a single dose of trastuzumab and pertuzumab in the context of the treatment of a metastatic breast cancer and resulting in fatal outcome despite optimal management.

Conclusions

Considering that targeted cancer therapies become increasingly effective, oncologists should be extremely cautious when treating patients at high risk of tumor lysis syndrome, even if they are not treated with cytotoxic chemotherapy, and determine appropriate prophylaxis.

Dissolution of extensive urolithiasis: extending the utility of rasburicase can avoid the need for surgical intervention and renal replacement therapy

A 79-year-old male with chronic myelomonocytic leukaemia and extensive bilateral renal stone disease was treated with intravenous rasburicase for persistent hyperuricaemia. Subsequent imaging revealed a complete dissolution of stone burden, avoiding the need for complex, invasive stone surgery and further renal replacement therapy.

Tumor lysis syndrome in the era of novel and targeted agents in patients with hematologic malignancies: a systematic review

Effective new treatments are now available for patients with hematologic malignancies. However, their propensity to cause tumor lysis syndrome (TLS) has not been systematically examined. A literature search identified published Phase I-III clinical trials of monoclonal antibodies (otlertuzumab, brentuximab, obinutuzumab, ibritumomab, ofatumumab); tyrosine kinase inhibitors (alvocidib [flavopiridol], dinaciclib, ibrutinib, nilotinib, dasatinib, idelalisib, venetoclax [ABT-199]); proteasome inhibitors (oprozomib, carfilzomib); chimeric antigen receptor (CAR) T cells; and the proapoptotic agent lenalidomide. Abstracts from major congresses were also reviewed. Idelalisib and ofatumumab had no reported TLS. TLS incidence was ≤5 % with brentuximab vedotin (for anaplastic large-cell lymphoma), carfilzomib and lenalidomide (for multiple myeloma), dasatinib (for acute lymphoblastic leukemia), and oprozomib (for various hematologic malignancies). TLS incidences were 8.3 and 8.9 % in two trials of venetoclax (for chronic lymphocytic leukemia [CLL]) and 10 % in trials of CAR T cells (for B-cell malignancies) and obinutuzumab (for non-Hodgkin lymphoma). TLS rates of 15 % with dinaciclib and 42 and 53 % with alvocidib (with sequential cytarabine and mitoxantrone) were seen in trials of acute leukemias. TLS mitigation was employed routinely in clinical trials of alvocidib and lenalidomide. However, TLS mitigation strategies were not mentioned or stated only in general terms for many studies of other agents. The risk of TLS persists in the current era of novel and targeted therapy for hematologic malignancies and was seen to some extent with most agents. Our findings underscore the importance of continued awareness, risk assessment, and prevention to reduce this serious potential complication of effective anticancer therapy.

Rasburicase in the management of tumor lysis: an evidence-based review of its place in therapy

Tumor lysis syndrome (TLS) is a potentially life-threatening complication of cancer therapy characterized by two or more of the following laboratory abnormalities: hyperuricemia, hyperkalemia, hypocalcemia, and hyperphosphatemia, with resultant end-organ damage, eg, renal failure, seizures, or cardiac arrhythmias. High-risk patients include those with highly proliferative cancers and/or large tumor burdens, particularly in the setting of highly effective chemotherapy, among other risk factors. Before 2002, antihyperuricemic drug therapy was limited to allopurinol, a xanthine oxidase inhibitor. Rasburicase, a recombinant urate oxidase, was approved by the US Food and Drug Administration for children in 2002 and adults in 2009, ushering in a new era in TLS therapy. We attempted to critically appraise the available evidence supporting the perceived benefits of rasburicase in the management of TLS. A Medline search yielded 98 relevant articles, including 26 retrospective and 22 prospective studies of rasburicase for the treatment of TLS, which were then evaluated to determine the best available evidence for the effectiveness of rasburicase in terms of disease-oriented, patient-oriented, and economic outcomes. Rasburicase is now a standard of care for patients at high risk of TLS despite continuing debate on the correlation between its profound and rapid lowering of plasma uric acid levels with hard patient outcomes, eg, need for renal replacement therapy and mortality. Rasburicase is dramatically effective in lowering plasma uric acid levels. The mortality and cost-effectiveness benefits of this expensive drug remain to be conclusively proven, and well designed, randomized controlled trials are needed to answer these fundamentally important questions.

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.

Seizure-induced acute urate nephropathy: case report and review

Urate nephropathy is observed primarily in patients treated for malignancy, but several other predisposing conditions are recognized. We report a case in which urate nephropathy complicated status epilepticus and review the literature regarding previous similar cases. In addition, we discuss current views of the pathophysiology of acute kidney injury due to urate nephropathy. This case illustrates the value of carefully examining the urine of patients with acute kidney injury to identify causes that may have a specific treatment.

Rasburicase causing severe oxidative hemolysis and methemoglobinemia in a patient with previously unrecognized glucose-6-phosphate dehydrogenase deficiency

Rasburicase is frequently used in tumor lysis syndrome (TLS). Although it is very well tolerated, it can cause severe oxidative hemolytic anemia and methemoglobinemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. We report another case of rasburicase-induced methemoglobinemia in a patient with previously unrecognized G6PD deficiency and review the cases of methemoglobinemia and oxidative hemolysis reported in the literature to date. Patients from ethnicities in which G6PD deficiency is prevalent at high risk of TLS should be screened for G6PD deficiency prior to administration of rasburicase where practical. Asymptomatic decrease in oxygen saturation by oximetry and cyanosis are signs of methemoglobinemia; patients recover with conservative measures including supplemental oxygen and packed red cell transfusion.