Advances in the management of malignancy-associated hyperuricaemia

Association between serum urate levels, gout and breast cancer: observational and Mendelian randomization analyses

Background

It is hypothesized that uric acid acts as an antioxidant and may prevent cancer. However, observational studies regarding the relationship between serum urate levels, gout, and breast cancer have provided discrepant evidence. Therefore, the objective of our study was to investigate the potential causal relationship between them.

Methods

This study included 12,451 participants from the National Health and Nutrition Examination Survey (NHANES) 2009-2018. Associations between urate levels, gout, and breast cancer were examined using multivariate logistic regression analysis. In addition, to assess the causal link among them, Mendelian randomization (MR) analysis was conducted, primarily using the inverse variance weighted (IVW) approach, supplemented by MR Egger and weighted median approaches, and a set of sensitivity analyses to test the robustness of the results, and finally, multivariate MR was used to adjust for confounders.

Results

In cross-sectional studies, urate levels [odds ratio (OR) 0.99, 95% confidence interval (CI): 0.89-1.09, P=0.80] and gout (OR 0.96, 95% CI: 0.53-1.76, P=0.90) were negatively associated with breast cancer risk after controlling for multiple confounders, although the P value was not significant. Two-sample MR analysis showed that serum urate levels were negatively associated with the estrogen receptor-negative (ER-) breast cancer (IVW, OR 0.916, 95% CI: 0.848-0.989, P=0.03) risk, but not significantly associated with overall and the estrogen receptor-positive (ER+) breast cancer (IVW, both P>0.05). In addition, gout was negatively associated with overall (IVW, OR 0.07, 95% CI: 0.008-0.594, P=0.02), ER+ (IVW, OR 0.062, 95% CI: 0.005-0.742, P=0.03), and ER- breast cancer (IVW, OR 0.041, 95% CI: 0.004-0.472, P=0.01) risk. These associations persisted after multivariate MR adjustment for smoking status, alcohol intake frequency, and body mass index (BMI).

Conclusions

Our study elucidated the relationship between uric acid, gout and breast cancer, and further studies are still needed in the future to clarify the mechanisms involved.

Streptomyces griseorubens as a microbial cell factory for extracellular uricase production and bioprocess optimization using statistical approach

BACKGROUND

Uricase is a bio-drug used to reduce urate accumulation in gout disease. Thus, there is a continuous demand for screening soil samples derived from a variety of different sources in order to isolate a strain that possesses a high potential for producing uricase.

METHODS

Streptomyces sp. strain NEAE-5 demonstrated a significant capacity for uricase production was identified based on the physiological, morphological and biochemical characteristics, as well as 16S rDNA sequencing analysis. Using a Plackett-Burman statistical design, the impact of eighteen process factors on uricase production by Streptomyces griseorubens strain NEAE-5 was investigated. Using central composite design, the most important variables that had a favourable positive impact on uricase production by Streptomyces griseorubens strain NEAE-5 were further optimized.

RESULTS

It is clear that the morphological and chemotaxonomic features of Streptomyces sp. strain NEAE-5 are typical for the Streptomyces genus. Phylogenetic analysis indicated that Streptomyces sp. strain NEAE-5 belongs to the genus Streptomyces and closely related to Streptomyces griseorubens which it has a 95-96% identity in 16S rDNA gene sequencing. Accordingly, the strain is proposed to be identified as Streptomyces griseorubens strain NEAE-5. The three factors that had the significant positive impacts on uricase production were uric acid, hypoxanthine, and yeast extract. As a result, the best conditions for achieving the highest experimental uricase production by Streptomyces griseorubens strain NEAE-5 after central composite design were (g/L): uric acid 6.96, glycerol 5, hypoxanthine 5.51, MgSO4.7H2O 0.1, KNO3 2, CaCl2 0.5, K2HPO4 0.5, NaCl 0.5, yeast extract 1.08. In addition, the period of incubation is seven days, pH 7.5 and 37 °C with an inoculum size of 2 mL (105 cfu/mL) /100 mL medium.

CONCLUSIONS

After optimization, the obtained uricase activity was 120.35 U/mL, indicating that the Streptomyces griseorubens strain NEAE-5 is a potent uricase producer and that the statistical approach used for optimization was appropriate.

Rescue Therapies for AKI in Onconephrology: Rasburicase and Glucarpidase

Tumor lysis syndrome (TLS) and high-dose methotrexate (HD MTX) toxicity can present with potentially severe complications, including acute kidney injury, in patients with malignancy. Guidelines for using rasburicase and glucarpidase as rescue therapies for TLS and HD MTX toxicity, respectively, are widely used by clinicians intending to mitigate organ toxicity and decrease morbidity and mortality as a consequence of cancer therapy. This review discusses the pathogenesis of TLS and HD MTX-associated toxicity, to understand the mechanism of action of these therapeutic agents and to review the currently available evidence supporting their use.

Modulation of Urate Transport by Drugs

BACKGROUND

Serum urate (SU) levels in primates are extraordinarily high among mammals. Urate is a Janus-faced molecule that acts physiologically as a protective antioxidant but provokes inflammation and gout when it precipitates at high concentrations. Transporters play crucial roles in urate disposition, and drugs that interact with urate transporters either by intention or by accident may modulate SU levels. We examined whether in vitro transporter interaction studies may clarify and predict such effects.

METHODS

Transporter interaction profiles of clinically proven urate-lowering (uricosuric) and hyperuricemic drugs were compiled from the literature, and the predictive value of in vitro-derived cut-offs like C_max/IC₅₀ on the in vivo outcome (clinically relevant decrease or increase of SU) was assessed.

RESULTS

Interaction with the major reabsorptive urate transporter URAT1 appears to be dominant over interactions with secretory transporters in determining the net effect of a drug on SU levels. In vitro inhibition interpreted using the recommended cut-offs is useful at predicting the clinical outcome.

CONCLUSIONS

In vitro safety assessments regarding urate transport should be done early in drug development to identify candidates at risk of causing major imbalances. Attention should be paid both to the inhibition of secretory transporters and inhibition or trans-stimulation of reabsorptive transporters, especially URAT1.

Use of Allopurinol to Mitigate 6-Mercaptopurine Associated Gastrointestinal Toxicity in Acute Lymphoblastic Leukemia

An essential component of acute lymphoblastic leukemia (ALL) therapy is the prolonged maintenance phase with daily 6-mercaptopurine (6-MP) as the cornerstone. While 6-MP is generally well-tolerated, some patients suffer from significant side effects such as gastrointestinal (GI) toxicity, including hepatitis, hypoglycemia, nausea, and pancreatitis, which can substantially limit the tolerated dose of 6-MP. These toxicities are thought to result from skewed metabolism of 6-MP leading to an accumulation of the 6-methylmercaptopurine (6-MMP) metabolite. Here, we describe current knowledge behind the use of allopurinol to modify 6-MP metabolism and improve tolerance to therapy. This method has been successfully used in adults with inflammatory bowel disease refractory to purine therapy and has been modified for use in children with GI toxicities related to 6-MP in maintenance therapy for ALL. Use of allopurinol for 6-MP related toxicities should be reserved for patients in which an alternative cause of signs or symptoms has been excluded and for whom non-pharmacologic measures have failed. When allopurinol is used, simultaneous dose reduction of 6-MP is required to avoid severe myelosuppression and related side effects, though overall combination therapy appears to be well-tolerated and effective when instituted appropriately.

Tumor lysis syndrome in childhood malignancies

BACKGROUND

Tumor lysis syndrome (TLS) is the most common life-threatening oncological emergency encountered by physicians treating children with lymphoproliferative malignancies. Healthcare providers should be aware of the condition in order to prevent occurrence and prompt timely management to avoid severe consequences.

OBJECTIVE

To provide an update on the current understanding, evaluation, and management of tumor lysis syndrome in childhood malignancies.

METHODS

A PubMed search was performed in Clinical Queries using the keywords 'tumor lysis syndrome' and 'malignancies' with Category limited to clinical trials and reviews for ages from birth to 18 years.

RESULTS

There were 22 clinical trials and 37 reviews under the search criteria. TLS is characterized by acute electrolyte and metabolic disturbances resulting from massive and abrupt release of cellular contents into the circulation due to breakdown of tumor cells. If left untreated, it can lead to multiorgan compromise and eventually death. Apart from close monitoring and medical therapies, early recognition of risk factors for development of TLS is also necessary for successful management.

CONCLUSIONS

Prophylactic measures to patients at risk of TLS include aggressive fluid management and judicious use of diuretics and hypouricemic agents. Both allopurinol and urate oxidase are effective in reducing serum uric acid. Allopurinol should be used as prophylaxis in low-risk cases while urate oxidase should be used as treatment in intermediate to high-risk cases. There is no evidence on better drug of choice among different urate oxidases. The routine use of diuretics and urine alkalinization are not recommended. Correction of electrolytes and use of renal replacement therapy may also be required during treatment of TLS.

Urate crystal deposition, prevention and various diagnosis techniques of GOUT arthritis disease: a comprehensive review

Gout is described as difficult in joint sore, uttermost ordinarily in the principal metatarsophalangeal joint, attend from formation of urate monosodium crystallization in a joint space. Analysis might be affirmed by recognizable proof of urate monosodium precious stones in synovial liquid of the influenced joint. There has been expanded enthusiasm for gout in common scholarly and clinical practice settings. The pervasiveness of both hyperuricemia and gout has ascended as most recent decade of time in created nations and in this way weight of gout as expanded. The relationship of hyperuricemia and gout with cardio results for chance of added advantages in mediation on hyperuricemia was featured in this audit. Imaging procedures have ended up being helpful for location of urate statement, even before the primary clinical indications, empowering the assessment of the degree of testimony and giving target estimation of precious stone exhaustion amid urate-bringing down treatment. In advancement, the indication defines the pre diagnostic of gout and associated commodities is advised to prevent the inflammation, that image procedures will assess the weight on statement as well reaction to urinary bringing down clinical procedure in chose patients, lastly amongst last key goal on social insurance for clinical evaluation with gout is to totally project urate gem stores. In spite of the fact that the formal determination is defined with arthrocentesis and resulting examination, CT and ultrasound discoveries on addition of evaluation and execution of infection administration. The standard therapy methodology is available for the patients and whose disease is refractory to standard therapy.

Gout: An old disease in new perspective - A review

Gout is a picturesque presentation of uric acid disturbance. It is the most well understood and described type of arthritis. Its epidemiology is studied. New insights into the pathophysiology of hyperuricemia and gouty arthritis; acute and chronic allow for an even better understanding of the disease. The role of genetic predisposition is becoming more evident. The clinical picture of gout is divided into asymptomatic hyperuricemia, acute gouty arthritis, intercritical period, and chronic tophaceous gout. Diagnosis is based on laboratory and radiological features. The gold standard of diagnosis is identification of characteristic MSU crystals in the synovial fluid using polarized light microscopy. Imaging modalities include conventional radiography, ultrasonography, conventional CT, Dual-Energy CT, Magnetic Resonance Imaging, nuclear scintigraphy, and positron emission tomography. There is remarkable progress in the application of ultrasonography and Dual-Energy CT which is bound to influence the diagnosis, staging, follow-up, and clinical research in the field. Management of gout includes management of flares, chronic gout and prevention of flares, as well as management of comorbidities. Newer drugs in the pharmacological armamentarium are proving successful and supplement older ones. Other important points in its management include patient education, diet and life style changes, as well as cessation of hyperuricemic drugs.

Gout and its comorbidities in the total population of Stockholm

OBJECTIVE

Study of prevalence of gout with concomitant diseases.

METHODS

Study population included all living persons in Stockholm County, Sweden, on January 1st 2013 (N=2,124,959). A diagnosis of gout was identified during 2013-2014, with information of diabetes mellitus and insulin resistance, hypertension, chronic heart failure, chronic kidney disease, alcohol abuse, and malignancies. Age-adjusted odds ratios (ORs) with 95% confidence intervals (95% CI) for women and men with gout, using individuals without gout as referents, were calculated.

RESULTS

Age-adjusted odds of co-morbidities among individuals with gout vs. those without gout were: diabetes mellitus and insulin resistance 3.97 (95% CI 3.65-4.31) in women and 1.88 (95% CI 1.78-1.99) in men; hypertension 4.02 (95% CI 3.69-4.37) in women and 3.21 (95% CI 3.06-3.37) in men; chronic heart failure 4.72 (95% CI 4.31-5.19) in women and 2.84 (95% CI 2.66-3.04) in men; chronic kidney disease 2.08 (95% CI 1.50-2.87) in women and 2.39 (95% CI 2.15-2.66) in men; alcohol abuse 8.98 (95% CI 8.15-9.80) in women and 4.38 (95% CI 4.10-4.69) in men; and malignancies 1.32 (95% CI 1.17-1.48) in women and 1.13 (95% CI 1.06-1.21) men.

CONCLUSION

Gout is a warning sign for concomitant diseases, e.g. alcoholism, diabetes, cardiovascular diseases, and cancer. KEY MESSAGES.

Treatment of Burkitt lymphoma in adults

Since its initial description in 1958, Burkitt lymphoma has become a prototype for our understanding of the pathogenesis and optimal treatment of aggressive lymphomas. The evolution of the treatment of this disease is explored and current therapeutic approaches evaluated. Special issues in the treatment of Burkitt lymphoma will also be discussed, including considerations in patients infected with HIV and current views on prophylactic measures and treatment of tumor lysis syndrome.

Tumour lysis syndrome and acute kidney injury in high-risk haematology patients in the rasburicase era. A prospective multicentre study from the Groupe de Recherche en Réanimation Respiratoire et Onco-Hématologique

In tumour lysis syndrome (TLS), metabolic alterations caused by the destruction of malignant cells manifest as laboratory abnormalities with (clinical TLS) or without (laboratory TLS) organ dysfunction. This prospective multicentre cohort study included 153 consecutive patients with malignancies at high risk for TLS (median age 54 years (interquartile range, 38-66). Underlying malignancies were acute leukaemia (58%), aggressive non-Hodgkin lymphoma (29.5%), and Burkitt leukaemia/lymphoma (12.5%). Laboratory TLS developed in 17 (11.1%) patients and clinical TLS with acute kidney injury (AKI) in 30 (19.6%) patients. After adjustment for confounders, admission phosphates level (odds ratio [OR] per mmol/l, 5.3; 95% confidence interval [95% CI], 1.5-18.3), lactic dehydrogenase (OR per x normal, 1.1; 95%CI, 1.005-1.25), and disseminated intravascular coagulation (OR, 4.1; 95%CI, 1.4-12.3) were associated with clinical TLS; and TLS was associated with day-90 mortality (OR, 2.45; 95%CI, 1.09-5.50; P = 0.03). In this study, TLS occurred in 30.7% of high-risk patients. One third of all patients experienced AKI, for which TLS was an independent risk factor. TLS was associated with increased mortality, indicating a need for interventional studies aimed at decreasing early TLS-related deaths in this setting.

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

WHAT IS KNOWN AND OBJECTIVE

Tumour lysis syndrome (TLS) is an oncologic emergency with potentially devastating consequences classically associated with cytotoxic chemotherapy. In recent years, molecularly targeted drugs have assumed an increasingly important role in cancer therapeutics. The possibility of TLS is often overlooked in this setting. Rasburicase, a recombinant urate oxidase, is remarkably effective in treating hyperuricemia, thought to be central to the pathogenesis of renal injury in TLS. Our objective is to review the literature on TLS especially as it pertains to targeted therapies and summarize current knowledge and provide future directions regarding the role of rasburicase in the management of TLS.

METHODS

A MEDLINE search was conducted using PubMed and the keyphrase 'tumor lysis syndrome' to identify articles describing TLS with a broad range of novel anti-cancer agents. Meeting abstracts were also reviewed. Additionally, the biomedical literature was searched using the keyword 'rasburicase'.

RESULTS AND DISCUSSION

Tumour lysis syndrome has been described with nearly every class of 'targeted therapy'. This is not surprising as any drug causing death of cancer cells by any mechanism may lead to TLS in the appropriate setting. Although there is a wealth of evidence suggesting that rasburicase is extremely effective in correcting hyperuricemia, prospective trials showing that it improves hard outcomes such as acute renal failure, need for dialysis and mortality are lacking. Furthermore, much lower doses and durations of therapy than approved appear to be effective in controlling hyperuricemia, potentially leading to enormous cost savings.

WHAT IS NEW AND CONCLUSION

Any effective cancer therapy can lead to TLS. Physicians should consider the risk of TLS on a case-by-case basis and determine appropriate prophylaxis. The role of rasburicase continues to evolve. Randomized controlled trials evaluating clinically relevant outcomes are needed.

Evaluation of a low, weight-based dose of rasburicase in adult patients for the treatment or prophylaxis of tumor lysis syndrome

PURPOSE

Rasburicase is a recombinant urate oxidase enzyme generally reserved for the treatment or prevention of hyperuricemia in patients that are at high risk of developing tumor lysis syndrome (TLS). The primary objective of this study is to evaluate and characterize the outcomes of patients receiving low dose rasburicase for treatment or prophylaxis of hyperuricemia secondary to TLS.

PATIENTS/METHODS

A retrospective chart review between April 1, 2007 and September 31, 2008 was completed. All adult patients who received a dose of 0.05mg/kg with either a leukemia or lymphoma diagnosis in addition to at least two TLS risk factors: WBC ≥ 50 × 109/L, LDH 2 × ULN, uric acid ≥ 8 mg/dl, SCr ≥ 1.5 mg/dl were included. Forty-eight patients received rasburicase for prophylaxis (n = 18) or treatment (n = 30) of TLS.

RESULTS

Forty patients achieved and maintained a uric acid less than 8 mg/dL, 24 h after receipt of a single dose of rasburicase without the requirement for renal replacement therapy. A statistically significant decrease in UA was achieved in all patients when compared to baseline (p < 0.001). Cost analysis revealed a $ 1.96 million (96%) direct cost savings for the 48 patients in this study when compared to the cost of manufacturer's dosing recommendation.

CONCLUSIONS

Low dose rasburicase was efficacious and cost effective for both prophylaxis and treatment of TLS. Administration of a single dose of 0.05mg/kg of rasburicase was sufficient in correcting uric acid levels for most patients.

SFCE (Société Française de Lutte contre les Cancers et Leucémies de l'Enfant et de l'Adolescent) recommendations for the management of tumor lysis syndrome (TLS) with rasburicase: an observational survey

Rasburicase (Fasturtec), a recombinant urate oxidase, is highly effective in preventing and treating hyperuricemia in children with hematologic malignancies. We conducted a prospective, multicenter observational study in 174 patients at 8 pediatric hemato-oncology centers to establish whether the SFCE (Société Française de Lutte contre les Cancers et Leucémies de l'Enfant et de l'Adolescent) recommendations for the use of rasburicase in the management of pediatric patients at risk of tumor lysis syndrome (TLS) are valid in routine clinical practice. Patients were classified as being at high or low risk of TLS according to the Children's Oncology Group criteria and were treated in accordance with the SFCE recommendations. The primary end point was the number of patients requiring a higher dose of rasburicase or a longer duration of treatment than advised in the SFCE recommendations. Of the 135 patients at high risk of TLS, 27 patients received a higher dose and 35 patients received a longer duration of treatment. Some patients received treatment with rasburicase for less than the recommended duration (median 4 d for high-risk patients). One patient required hemodialysis. Only minor adjustments to the SFCE recommendations were required to ensure the optimal use of rasburicase in pediatric patients at risk of TLS.

Lowering serum urate does not improve endothelial function in patients with type 2 diabetes

AIMS/HYPOTHESIS

Endothelial dysfunction contributes to excess cardiovascular risk in patients with type 2 diabetes. There is strong evidence of an association between high serum uric acid concentrations and endothelial dysfunction, and uric acid has been proposed as an independent cardiovascular risk factor in type 2 diabetes. We hypothesised that lowering of uric acid concentrations might allow restoration of endothelial function in this high-risk group.

METHODS

Intravenous urate oxidase (1.5 mg) was administered to ten patients with type 2 diabetes and ten healthy participants in a two-way, randomised, placebo-controlled, crossover study. Forearm blood flow responses to intra-brachial acetylcholine, sodium nitroprusside and N(G)-monomethyl-L-arginine (L-NMMA) were measured using venous occlusion plethysmography. The augmentation index (AIx) was determined by pulse wave analysis as a measure of large arterial stiffness.

RESULTS

Acetylcholine and L-NMMA evoked lesser responses in patients with type 2 diabetes than in healthy participants. Baseline AIx was higher in patients with type 2 diabetes (mean +/- SD: 13.1 +/- 6.9%) than in healthy participants (2.0 +/- 5.1%; p = 0.006). Urate oxidase lowered serum uric acid concentrations by 64 +/- 11% (p < 0.001), but this had no effect on forearm blood flow responses or AIx in either group.

CONCLUSIONS/INTERPRETATION

Substantial short-term lowering of uric acid did not have a direct vascular effect, suggesting that, on its own, this might not be an effective strategy for restoring endothelial function in patients with type 2 diabetes.

Tumor lysis syndrome in elderly

The majority of cancers occur in adults over the age of 65, with about 70% of all cancer deaths in this population. Tumor lysis syndrome (TLS) is a complication of hematological and others malignancies, caused by massive tumor cell lysis due to chemotherapy, immunotherapy, radiotherapy. TLS can determine an alteration of the body's normal homeostatic mechanisms and cause hyperuricemia, hyperkaliemia, hyperphosphatemia, hypocalcaemia and uremia. Aggressive fluid administration has been recommended in all patients presumed to be at risk of this syndrome. Hyperkaliemia has to be correct with hypertonic glucose, resins and dialysis. Initial treatment of hyperphosphatemia includes phosphate binders. The cornerstone of prevention and treatment of hyperuricemia includes both inhibiting the formation of uric acid as well as increasing its renal clearance through urinary alkalinization, allopurinol, rasburicase. Conventional management to prevent acute renal failure consists of intravenous hydration, diuretic therapy and urinary alkalinization. The management of TLS in elderly patients is often complicated by the renal and the heart senescence and by the presence of multiple co morbid conditions, polypharmacy and difficulties with adherence to complex medication and dietary regimens.

Rasburicase in the prevention and treatment of tumour lysis syndrome

Tumour lysis syndrome (TLS) can be a life threatening complication of cancer therapy where cells undergo overwhelming lysis. The result is a pattern of metabolic abnormalities leading to acute renal failure and possible coagulopathy. Prophylactic pharmaceutical interventions can prevent this syndrome in almost all patients reducing possible admission to the intensive care unit. This article reviews the clinical efficacy, side effect profile, dosing and administration of rasburicase, an intravenous recombinant urate oxidase used in patients at risk of Tumour lysis syndrome due to a high tumour burden or where treatment is required. Rasburicase is an expensive but effective treatment option in the prevention and treatment of tumour lysis syndrome.

Resultados del protocolo SHOP LNHB98 (LMB89) en pacientes de edad pediátrica afectados de linfoma no hodgkiniano de células B

BACKGROUND AND OBJECTIVE

After the good results obtained by the Société Française d'Oncologie Pédiatrique (SFOP) regarding the pediatric B-type non-Hodgkin's (Burkitt and large B-cell) lymphoma and L3 leukemia, the Sociedad Española de Hematología y Oncología Pediátricas (SHOP) decided to use the same treatment protocol.

PATIENTS AND METHOD

Pediatric patients diagnosed with B-type non-Hodgkin's lymphoma without a previous history of malignant diseases were eligible for this study. They were classified in 3 groups of risk: group A (resected stage I and abdominal stage II), group B (not eligible for groups A or C), and group C (with central nervous system involvement and L3 leukemia). All received treatment according to the SFOP's LMB89 protocol.

RESULTS

A total of 153 patients were considered in this multicenter, prospective and non-randomized trial (1997-2005). The global and event-free survival (EFS) were found to be of 88% (0.88; 95% confidence interval [CI], 0.83-0.93) and 85% (0.85; 95% CI, 0.79-0.90), respectively. The EFS was 100% for the group A (n = 16), 86% (0.86; 95% CI, 0.79-0.92) for the group B (n = 113), and 68% (0.68; 95% CI, 0.49-0.86) for the group C (n = 24).

CONCLUSIONS

The results confirm the good efficiency of the LMB89 protocol for treating B-cell lymphoma and L3 leukemia, despite having diminished the treatment intensity in the less risk groups. The worst prognostic factor was found to be a central nervous system involvement, whereas being younger than 10 years was confirmed to be a favorable prognostic factor. In addition, no differences were evidenced between Burkitt and large B-cell lymphoma.

Clarifying the Role of Rasburicase in Tumor Lysis Syndrome

Tumor lysis syndrome (TLS) is a complication of malignancies with high tumor cell proliferation, tumor burden, and chemosensitivity. It manifests with the release of intracellular components and results in hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia. These biochemical abnormalities may lead to serious complications such as renal failure, cardiac dysrhythmias, and death. Rasburicase, a recombinant urate oxidase enzyme, is a new agent indicated in the treatment or prophylaxis of hyperuricemia in pediatric patients with cancer who are at high risk for TLS. We reviewed the evidence for treatment with this agent compared with standard therapy with allopurinol. Rasburicase may be considered for use in patients with hyperuricemia at presentation and in patients at high risk for TLS that would otherwise result in a delay in chemotherapy. However, randomized controlled trials are required to establish the comparative efficacy of rasburicase in the adult population. Preliminary evidence suggests that single-dose or reduced-dose rasburicase may be effective in the prophylaxis and the treatment of hyperuricemia and TLS. However, to our knowledge, there is no evidence comparing clinically relevant outcomes such as acute renal failure or dialysis.

Reduced-Dose Rasburicase in the Treatment of Adults with Hyperuricemia Associated with Malignancy

Tumor lysis syndrome is a life-threatening complication of chemotherapy for patients with leukemia and large tumors with a high proliferative index, such as Burkitt's lymphoma. The syndrome is characterized by hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia. The standard of care for hyperuricemia consists of hydration with or without alkalinization and administration of allopurinol. When treated in this manner, patients often experience persistent hyperuricemia that lasts several days after the start of antineoplastic therapy; sometimes they develop uric acid nephropathy as a consequence. Rasburicase, a recombinant urate oxidase enzyme, quickly removes large amounts of uric acid from plasma. The drug is approved by the United States Food and Drug Administration for management of elevated plasma uric acid levels in pediatric patients with leukemia, lymphoma, or solid tumor malignancies who are receiving chemotherapy. We undertook a retrospective review of adult patients treated with a single dose of rasburicase 6 mg for hyperuricemia associated with malignancy. Ten patients received one 6-mg dose of rasburicase, and one patient received two 6-mg doses as an adjuvant therapy to normalize uric acid levels. In most of the patients, a single 6-mg dose of rasburicase was effective in correcting uric acid levels in the typical time between diagnosis and start of antineoplastic therapy.

Recurrent chemotherapy-induced tumor lysis syndrome (TLS) with renal failure in a patient with chronic lymphocytic leukemia - successful treatment and prevention of TLS with low-dose rasburicase

INTRODUCTION

Rasburicase is a recombinant urate oxidase that is produced by a genetically modified Saccharomyces cerevisiae and has been approved for prophylaxis and treatment of tumor lysis syndrome in 2001. In several studies, rasburicase, given at a dose of 0.15-0.2 mg/kg for up to 7 d, proved to be highly effective in lowering urate levels.

CASE REPORT

We report the case of a patient with chronic lymphatic leukemia (CLL) who experienced tumor lysis syndrome (TLS) with acute renal failure after fludarabine/cyclophosphamide chemotherapy and after bendamustine treatment. During the first episode of TLS, after fludarabine/cyclophosphamide (creatinine 3.3 mg/dL, urate 24.6 mg/dL), the patient received rasburicase 0.2 mg/kg for 3 d. Urate levels decreased below the lower limit of normal and renal function recovered. After bendamustine therapy, given for disease progression 8 months later, TLS with acute oliguric renal failure re-occurred (creatinine 3.1 mg/dL, urate 20.8 mg/dL). The patient was treated with hyperhydration and two doses of rasburicase (0.056 mg/kg), resulting in a prompt decrease of the urate level and recovery of renal function. Both episodes of TLS were successfully treated with rasburicase in a lower dose than recommended by the manufacturer. During a second bendamustine course, TLS was successfully treated by low doses of rasburicase (0.056 mg/kg for 2 d).

CONCLUSION

This is the first report of TLS in CLL after bendamustine chemotherapy reported in the literature. Treatment and prevention of TLS by low doses of rasburicase is possible and cost-effective.

Management of hyperuricemia with rasburicase review

Tumor lysis syndrome (TLS) is a serious complication in patients with hematological malignancies. Massive lysis of tumor cells can lead to hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcaemia. These metabolic disturbances may result in renal failure, because of precipitation of uric acid crystals and calcium phosphate salts in the kidney. The standard prophylaxis or treatment of hyperuricemia consists of decreasing uric acid production with allopurinol and facilitating its excretion by urinary alkalinization and hyperhydration. By inhibiting the enzyme xanthine oxidase, allopurinol blocks the conversion of hypoxanthine and xanthine into uric acid. An alternative treatment is urate oxidase which oxidates uric acid into allantoin. Allantoin is 5-10 times more soluble than uric acid and is therefore excreted easily. In several clinical trials rasburicase, the recombinant form of urate oxidase, has shown to be very effective in preventing and treating hyperuricemia. Rasburicase, in contrast with the non-recombinant form of urate oxidase uricozyme, is associated with a low incidence of hypersensitivity reactions. In addition to the demonstrated clinical benefit, rasburicase also proved to be a cost-effective option in the management of hyperuricemia.

Use of Single-Dose Rasburicase in an Obese Female

OBJECTIVE:

To report the use of single-dose rasburicase in an obese patient.

CASE SUMMARY:

A 53-year-old obese African American woman weighing 136 kg (ideal body weight [IBW] 55 kg) with new-onset chronic myelomonocytic leukemia in leukocytic blast crisis was treated with hydroxyurea 5 g daily. In addition, she received allopurinol 300 mg daily for prevention of tumor lysis syndrome (TLS). The following day, allopurinol was discontinued and rasburicase was administered at a dose of 0.2 mg/kg of IBW for a serum uric acid level of 11.9 mg/dL. The patient's serum uric acid level decreased to 1.9 mg/dL 48 hours after a single dose.

DISCUSSION:

Rasburicase is indicated for the initial management of elevated plasma uric acid levels in patients with hematologic and solid tumor malignancies who are at risk for TLS. This case is unique because the patient received one dose of rasburicase followed by allopurinol rather than 5 daily doses of rasburicase. Additionally, the dose was based on IBW rather than actual body weight. Efficacy of this approach is apparent from the uric acid levels and the lack of hemodialysis requirements.

CONCLUSIONS:

A single dose of rasburicase (based on IBW) followed by allopurinol can effectively prevent TLS based on serum uric acid concentration. This approach resulted in a substantial cost savings.

Treatment of impending tumor lysis with single-dose rasburicase

OBJECTIVE

To report the experience of using rasburicase as a single-dose treatment for childhood leukemia presenting with hyperuricemia.

CASE SUMMARIES

Three children with acute lymphoblastic leukemia presenting with hyperuricemia received rasburicase as a single intravenous dose just prior to the start of chemotherapy. This was followed by rapid reduction of serum uric acid levels within 24 hours, which remained low throughout induction therapy while allopurinol and hydration therapy without urinary alkalinization ensued. Subclinical tumor lysis was evidenced by the appearance of hyperphosphatemia and hypocalcemia in all cases and hyperkalemia in 1 patient. These abnormalities were transient, and each patient's renal function gradually improved from pretreatment baseline without requiring dialysis.

DISCUSSION

Our experience suggests that hyperuricemia in children at risk for tumor lysis can be managed with a briefer regimen of rasburicase than the recommended 5- to 7-day course.

CONCLUSIONS

A shorter course of rasburicase treatment, including single-dose injection, is feasible and will improve the cost-effectiveness profile of the otherwise expensive compound.

Treatment by design in leukemia, a meeting report, Philadelphia, Pennsylvania, December 2002

Novel approaches have been designed to treat leukemia based on our understanding of the genetic and biochemical lesions present in different malignancies. This meeting report summarizes some of the recent advances in leukemia treatment. Based on the discoveries of cellular oncogenes, chromosomal translocations, monoclonal antibodies, multidrug resistance pumps, signal transduction pathways, genomics/proteonomic approaches to clinical diagnosis and mutations in biochemical pathways, clinicians and basic scientists have been able to identify the particular genetic mutations and signal transduction pathways involved as well as design more appropriate treatments for the leukemia patient. This meeting report discusses these exciting new therapies and the results obtained from ongoing clinical trials. Furthermore, rational approaches to treat complications of tumor lysis syndrome by administration of the recombinant urate oxidase protein, also known as rasburicase, which corrects the biochemical defect present in humans, were discussed. Clearly, over the past 25 years, molecular biology and biotechnology has provided the hematologist/oncologist novel bullets in their arsenal that will allow treatment by design in leukemia.

Rasburicase for the treatment and prevention of hyperuricemia

OBJECTIVE

To review the information currently available on rasburicase for treatment and prevention of hyperuricemia.

DATA SOURCES

MEDLINE (1966-August 2002) was searched for primary and review articles.

STUDY SELECTION/DATA EXTRACTION

Studies evaluating rasburicase, including abstracts and proceedings, were considered for inclusion. English-language literature was evaluated for the pharmacology, pharmacodynamics, pharmacokinetics, therapeutic use, and adverse effects of rasburicase.

DATA SYNTHESIS

Rasburicase, a recombinant urate oxidase, has been shown to be effective in lowering uric acid and preventing uric acid accumulation in patients with hematologic malignancies who had hyperuricemia or who were at high risk for developing hyperuricemia. It has been approved for pediatric use in the US.

CONCLUSIONS

In addition to allopurinol, hydration, and urinary alkalinization, rasburicase is a new alternative for the treatment and prevention of hyperuricemia in patients with hematologic malignancies. Its rapid onset of action and the ability to lower preexisting elevated uric acid levels are the advantages of rasburicase compared with allopurinol. It may allow the patient to receive chemotherapy treatment without delay.

Acute tumor lysis syndrome in solid tumors--a case report and review of the literature

PURPOSE

Tumor lysis syndrome (TLS) is a potential complication in cancer therapy. It may occur in highly sensitive tumors, especially in childhood cancers and acute leukemias, whereas it is rare in the treatment of adult solid tumors. TLS is characterized by hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia following massive lysis of malignant cells. Complications include acute renal failure and metabolic acidosis. We report the first case of TLS during chemotherapy in a patient with metastatic medulloblastoma, together with a review of the literature regarding the occurrence of TLS in patients with solid tumors.

METHODS

Data regarding clinical and biochemical parameters were extracted from the actual patients' files. Reports of TLS in the English language literature up to 2002 were identified by searching Medline.

RESULTS

A 23-year old male with metastatic medulloblastoma received chemotherapy with cisplatin and etoposide due to massive extracerebral manifestations including metastases to the liver, mediastinal lymph nodes and bone marrow metastases. The patient developed classical signs of TLS on the second day of chemotherapy, including acute renal failure. A 17-fold increase in plasma LDH up to 87608 U/l was observed together with a 4-fold increase in plasma creatinine. The patient was treated with aggressive hydration, allopurinol and repeated hemodialysis. During the following days the patient improved and the biochemical markers all returned to normal. REVIEW. Reviewing the literature, a total of 45 patients with solid tumors who developed TLS have been reported. Most of the patients presented with metastatic, therapy-sensitive disease. Although preventable in practically 100% of patients, TLS is a potentially fatal complication, and in this material the mortality rate was one in three. Risk factors included increased LDH, hyperuricemia and pretreatment azotemia.

CONCLUSIONS

TLS is only rarely associated with treatment of solid tumors. Precautions should be taken to avoid this potentially fatal complication in (chemo)therapy of solid tumors, especially in therapy-sensitive tumors presenting with bulky, metastatic disease and preexisting risk factors, including azotemia, elevated LDH and hyperuricemia. Prophylactic treatment to avoid TLS includes allopurinol, hydration prior to treatment and alkalization of the urine. Urate oxidase (rasburicase) is now beginning to replace allopurinol as a more effective way of reducing hyperuricemia and thereby the risk of TLS.

Elitek-rasburicase: an effective means to prevent and treat hyperuricemia associated with tumor lysis syndrome, a Meeting Report, Dallas, Texas, January 2002

Renal precipitation of uric acid associated with tumor lysis syndrome (TLS) is a major complication in the management of leukemia, lymphoma, and other drug-sensitive cancers. Management of hyperuricema has historically consisted of administration of allopurinol, hydration, alkalinization to maintain pH between 7.0 and 7.3, and in some cases diuresis. Allopurinol, a xanthine analogue, blocks xanthine oxidase and formation of uric acid. Urate oxidase converts uric acid to allantoin, which is 5-10 times more soluble than uric acid. Homo sapiens cannot express urate oxidase because of a nonsense mutation. Urate oxidase was initially purified from Aspergillus flavus fungus. Treatment with this nonrecombinant product had been effective in preventing renal precipitation of uric acid in cancer patients, but was associated with a relatively high frequency of allergic reactions. This enzyme was recently cloned from A. flavus and is now manufactured as a recombinant protein. Clinical trials have shown this drug to be more effective than allopurinol for prevention and treatment of hyperuricemia in leukemia and lymphoma patients. This drug has been approved in Europe as well as the US and several clinical trials are in progress to further determine its clinical utility in other patient subsets. The purpose of this meeting was to discuss usefulness of recombinant urate oxidase, also known as rasburicase, Fasturtec, and Elitek, for the management of TLS in certain cancer patients.

Investigations into the uricolytic properties of urate oxidase in a granivorous (Columba livia domestica) and in a carnivorous (Buteo jamaicensis) avian species

To study the uricolytic properties of urate oxidase in granivorous and carnivorous birds, experiments were conducted in pigeons (Columba livia domestica) and Red-tailed Hawks (Buteo jamaicensis). Plasma concentrations of allantoin and uric acid were determined at various times in experimental groups before and after receiving 100, 200, and 600 U/kg urate oxidase once daily and were compared with controls. All regimens caused a significant decrease in plasma uric acid concentrations within 2 days after the first administration, when compared with controls. Furthermore, both doses used in Red-tailed Hawks (200 and 100 U/kg) caused a significant postprandial suppression of plasma uric acid concentrations. Plasma allantoin concentrations were significantly higher when compared with controls. The ability of urate oxidase to prevent the physiological postprandial hyperuricaemia in Red-tailed Hawks and to reduce plasma uric acid concentrations to undetectable levels, shows the great potential of this drug for treating avian hyperuricaemia.

Clinical characteristics and treatment results of LMB/LMT regimen in children with non-Hodgkin's lymphoma

Lymphomas are the second most common cancers after leukemias seen in children in Turkey, although they rank third in many western countries. Ninety-seven patients with newly diagnosed, untreated non-Hodgkin's lymphoma, between April 1994 and December 1997, were included in this study. Modified lymphoma malign B (LMB) and lymphoma malign T (LMT) regimens were used for treatment of B- and T-cell disease, respectively. Ten (10.3%), 68 (70.1%), and 19 (19.6%) patients had stage II, III, and IV disease, respectively. Forty-eight, 19, 15, 9, 5, and 1 patients had tumors at abdominal, mediastinal, disseminated, head and neck, extranodal, and peripheral nodal locations, respectively. Seventy-two patients were treated with LMB89 regimen and 25 were treated with LMT89 regimen. Thirty-four patients had tumor lysis at diagnosis, and 9 patients required dialysis. Objective response rates were 75% for patients treated by LMB regimen and 92% for those treated by LMT regimen. Two-year overall survival rates were 90, 66.1, and 50.8% for patients with stage II, III, and IV disease, respectively. Two-year overall survival rates were 64.2% for LMB-treated patients and 70.8% for LMT-treated patients. Poor response at the end of cytoreductive treatment and age younger than 4 years were poor prognostic factors. Pediatric lymphomas could be treated safely and effectively by LMB and LMT regimens.

Acute tumor lysis syndrome in a patient with mixed small cell and non-small cell tumor

Tumor lysis syndrome, caused by massive tumor cell death, is an infrequent occurrence in solid tumors, and only a few cases of tumor lysis syndrome occurring in patients with lung cancer have been reported. We present a case of tumor lysis syndrome in a patient with mixed small cell and non-small cell lung cancer complicated by Listeria sepsis. Despite aggressive supportive measures with fluids, electrolytes, antibiotics, pressor agents, ventilation, and alkalinization of the urine, multiorgan failure developed, and the patient died on day 5 in the intensive care unit. Physicians should be aware of this infrequent but potentially fatal complication occurring in critically ill patients with bulky solid tumors so that early and aggressive therapeutic measures can be initiated and appropriate monitoring can be performed.

Urate-oxidase in the prevention and treatment of metabolic complications in patients with B-cell lymphoma and leukemia, treated in the Société Française d'Oncologie Pédiatrique LMB89 protocol

PURPOSE

To evaluate the frequency of metabolic complications and dialysis due to tumor lysis syndrome in patients with B-cell advanced-stage non-Hodgkin's lymphoma (NHL) and L3 leukemia at initiation of chemotherapy including the use of urate-oxidase.

PATIENTS AND METHODS

Retrospective review of the clinical records of 410 patients with stage III and IV B-cell NHL and L3 leukemia treated in France and prospectively registered in the LMB89 protocol.

RESULTS

During the first week of chemotherapy, only 34 of 410 patients recorded metabolic problems that included hypocalcemia (< 70 mg/dl) in 24 patients, hyperphosphatemia (> 6.5 mg/dl) in 28 and elevation of creatinine > or = 2 SD in 16. Six patients underwent dialysis for life-threatening problems and a seventh as a preventive measure. In the other 27 cases, metabolic problems were successfully resolved using urate-oxidase in combination with alkaline hyperhydration. Among the 410 patients, one case of hemolysis was reported and there was no severe allergic reaction to urate-oxidase.

CONCLUSIONS

Only 1.7% of patients in our study receiving urate-oxidase during their induction chemotherapy needed renal dialysis. Urate-oxidase was well tolerated, and used as prophylaxis and/or treatment of hyperuricemia and tumor lysis syndrome consistently gave a lower rate of renal and metabolic complications than in other series of similar patients.

Rasburicase: an innovative new treatment for hyperuricemia associated with tumor lysis syndrome

Rasburicase is a new treatment for hyperuricemia, a metabolic manifestation of tumor lysis syndrome (TLS). Rasburicase has a unique mechanism of action that allows uric acid byproducts to be easily excreted in the urine. Clinical trials have shown that rasburicase has a rapid onset of action that allows chemotherapy to be delivered on time and prevents hyperuricemia-related complications, including renal compromise. The drug has been used successfully in adults and children. The main side effect of rasburicase is the potential for a hypersensitivity reaction. The drug is contraindicated in patients with glucose 6-phosphate dehydrogenase (G6PD) deficiency because this can precipitate hemolytic anemia. The drug has not been studied in patients with a history of allergies or asthma. Oncology nurses play a major role in the assessment and management of TLS-related complications. They must assess patients for G6PD deficiency and signs and symptoms of hypersensitivity reaction before and during chemotherapy or other therapeutic interventions. Nurses play a direct role in preventing complications related to TLS and contributing to the quality of life in this patient population.

Urate oxidase in the prophylaxis or treatment of hyperuricemia: the United States experience

Nonrecombinant urate oxidase (Uricozyme, Sanofi-Synthélabo, Inc, Paris, France) is a highly effective uricolytic agent, but its use is associated with hypersensitivity reaction manifested mainly by bronchospasm in approximately 5% of patients. Recently, several multi-institutional studies have evaluated the efficacy and safety of a recombinant urate oxidase (rasburicase). In a phase I/II study, all 131 patients with newly diagnosed acute lymphoblastic leukemia (ALL) or stage III/IV non-Hodgkin's lymphoma (NHL) experienced rapidly decreased plasma uric acid concentrations after receiving recombinant urate oxidase. Serum creatinine levels also decreased significantly. Toxicity was negligible, and none of the patients required dialysis. In a phase III trial, children with newly diagnosed ALL or stage III/IV NHL were stratified and randomized to receive recombinant urate oxidase or allopurinol. Results showed that the 27 patients who received recombinant urate oxidase had a significantly lower plasma uric acid concentration and a more rapid decline in serum creatinine level than did the 25 who took allopurinol. One patient in the recombinant urate oxidase group had hemolysis of unknown cause, and one in the allopurinol group required hemofiltration for hyperphosphatemia. To further assess the safety profile of recombinant urate oxidase, the data on 245 patients (173 children and 72 adults) who received this agent in a compassionate-use program were reviewed retrospectively. The drug produced dramatic decreases in uric acid concentrations in all patients. Nine patients (four children and five adults) had mild adverse reactions that were drug-related or of unknown etiology. These data suggest that recombinant urate oxidase is safe and effective in the prophylaxis and treatment of hyperuricemia associated with malignancy or chemotherapy.

Fluid and electrolyte abnormalities

Patients with cancer are at risk for developing a variety of fluid and electrolyte disturbances caused by the disease process or by complications from therapy. An understanding of the pathophysiology of these potential abnormalities allows the clinician to manage patients expectantly and to avoid severe metabolic disarray by correcting imbalances promptly.

Tumour lysis syndrome during anaesthesia

We describe a child who developed acidosis, hyperkalaemia and cyanosis while emerging from an otherwise uneventful anaesthetic. A diagnosis of tumour lysis syndrome was suspected and confirmed biochemically. Although this syndrome is usually associated with chemotherapy and has been described to occur spontaneously, it has not previously been reported as being associated with anaesthesia.

Difficult gout and new approaches for control of hyperuricemia in the allopurinol-allergic patient

A major obstacle to the treatment of hyperuricemia in patients allergic to allopurinol is the limited availability of suitable, equally effective, alternative, urate-lowering drugs. Conventional uricosuric drugs, including probenecid and sulfinpyrazone, are recommended for allopurinol- intolerant patients with gout and "underexcretion" hyperuricemia who have normal renal function and no history of nephrolithiasis. Therapeutic options in those in whom traditional uricosuric drugs are contraindicated, ineffective, or poorly tolerated include slow oral desensitization to allopurinol and cautious administration of oxipurinol. Allopurinol desensitization is useful particularly in those who have failed other treatment modalities. If available (as in Europe, South Africa, and Japan), benzbromarone may be tried in patients with gout and mild-to-moderate renal insufficiency. Recombinant urate oxidase can be used in the short-term prophylaxis and treatment of chemotherapy- associated hyperuricemia in patients with lymphoproliferative and myeloproliferative disorders. Hyperuricemia and gout occur with increased frequency in cyclosporine-treated allograft transplant recipients. The management of gout in these patients is complicated by two main factors: cyclosporine-induced renal impairment, and interactions with medications used to preserve the allograft.

Recombinant urate oxidase for the prophylaxis or treatment of hyperuricemia in patients With leukemia or lymphoma

PURPOSE

To improve the control of hyperuricemia in patients with leukemia or lymphoma, we tested a newly developed uricolytic agent, recombinant urate oxidase (SR29142; Rasburicase; Sanofi-Synthelabo, Inc, Paris, France), which catalyzes the oxidation of uric acid to allantoin, a highly water-soluble metabolite readily excreted by the kidneys.

PATIENTS AND METHODS

We administered Rasburicase intravenously, at 0.15 or 0.20 mg/kg, for 5 to 7 consecutive days to 131 children, adolescents, and young adults with newly diagnosed leukemia or lymphoma, who either presented with abnormally high plasma uric acid concentrations or had large tumor cell burdens. Blood levels of uric acid, creatinine, phosphorus, and potassium were measured daily. The pharmacokinetics of Rasburicase, the urinary excretion rate of allantoin, and antibodies to Rasburicase were also studied.

RESULTS

At either dosage, the recombinant enzyme produced a rapid and sharp decrease in plasma uric acid concentrations in all patients. The median level decreased by 4 hours after treatment, from 9.7 to 1 mg/dL (P =.0001), in the 65 patients who presented with hyperuricemia, and from 4.3 to 0.5 mg/dL (P =.0001) in the remaining 66 patients. Despite cytoreductive chemotherapy, plasma uric acid concentrations remained low throughout the treatment (daily median level, 0.5 mg/dL). The urinary excretion rate of allantoin increased during Rasburicase treatment, peaking on day 3. Serum phosphorus concentrations did not change significantly during the first 3 days of treatment, decreased significantly by day 4 in patients presenting with hyperuricemia (P =.0003), and fell within the normal range in all patients by 48 hours after treatment. Serum creatinine levels decreased significantly after 1 day of treatment in patients with or without hyperuricemia at diagnosis (P =.0003 and P =.02, respectively) and returned to normal range in all patients by day 6 of treatment. Toxicity was negligible, and none of the patients required dialysis. The mean plasma half-lives of the agent were 16.0 +/- 6.3 (SD) hours and 21.1 +/- 12.0 hours, respectively, in patients treated at dosages of 0.15 or 0.20 mg/kg. Seventeen of the 121 assessable patients developed antibodies to the enzyme.

CONCLUSION

Rasburicase is safe and highly effective for the prophylaxis or treatment of hyperuricemia in patients with leukemia or lymphoma.

Efficacy and safety of desensitization to allopurinol following cutaneous reactions

OBJECTIVE

To evaluate the long-term efficacy and safety of slow oral desensitization in the management of patients with hyperuricemia and allopurinol-induced maculopapular eruptions.

METHODS

A retrospective evaluation of an oral desensitization regimen using gradual dosage-escalation of allopurinol in 32 patients (30 with gout and 2 with chronic lymphocytic leukemia) whose therapy was interrupted because of a pruritic cutaneous reaction to the drug.

RESULTS

Twenty-one men and 11 women with a mean age of 63 years (range 17-83 years), a mean serum urate level of 618 micromoles/liter (range 495-750) (or, mean 10.4 mg/dl [range 8.3-12.6]), and a mean serum creatinine level of 249 micromoles/liter (range 75-753) (or, mean 2.8 mg/dl [range 0.8-8.5]) were studied. Desensitization failed in 4 patients because of unmanageable recurrent rash. Twenty-eight patients completed the desensitization procedure to a target allopurinol dosage of 50-100 mg/day, 21 without deviation from the protocol for a mean of 30.5 days (range 21-56 days) and 7 requiring dosage adjustments because of a recurrent rash over 53.8 days (range 40-189 days). Seven of these 28 patients developed late cutaneous reactions 1-20 months postdesensitization, 4 responding to dosage modification and 3 discontinuing the drug. Twenty-five of the 32 patients (78%) continued to take allopurinol; their mean duration of followup was 32.6 months (range 3-92 months) and the mean postdesensitization serum urate level was 318 micromoles/liter (range 187-452) (or, mean 5.3 mg/dl [range 3.0-7.5]).

CONCLUSION

The study confirms the long-term efficacy and safety of slow oral desensitization to allopurinol in patients with maculopapular eruptions, particularly in those with gout, who cannot be treated with uricosurics or other urate-lowering drugs. Although pruritic skin eruptions may recur both during and after desensitization, most of these cutaneous reactions can be managed by temporary withdrawal of allopurinol and dosage adjustment.

Hyperuricemia and renal insufficiency associated with malignant disease: urate oxidase as an efficient therapy?

Hyperuricemia is a common finding in patients with malignant diseases. Chemotherapy can induce life-threatening tumor lysis syndrome with severe hyperuricemia, other metabolic abnormalities, and acute renal failure. Intrarenal precipitation of uric acid contributes to renal insufficiency in this situation. Allopurinol, by preventing the conversion of hypoxanthine and xanthine to uric acid, has been long considered the standard pharmacological approach to hyperuricemia and prevention of tumor lysis syndrome. However, allopurinol itself may facilitate precipitation of xanthine crystals and has little influence on already-formed uric acid crystals deposited in the kidney. Urate oxidase further oxidizes uric acid to the highly water-soluble allantoin in mammals, except humans, who lack this enzyme. We report four cases of hyperuricemia (initial serum uric acid concentrations, 14.0 to 25.0 mg/dL) associated with malignant diseases treated with exogenous urate oxidase. Two of the patients showed full-blown tumor lysis syndrome. A single urate oxidase infusion (1,000 U) readily reduced serum uric acid levels in all patients. Furthermore, renal insufficiency, determined by serum creatinine concentrations, improved in three of the four patients. No adverse effects were observed. Currently, a recombinant urate oxidase is undergoing clinical testing and may make this efficient therapy more widely available. We believe that treatment with urate oxidase is a safe and efficient therapy for patients with cancer-associated hyperuricemia and may be effective even in individuals with only moderately elevated serum uric acid concentrations.