Prevention and treatment of hyperuricemia in hematological malignancies

Adverse drug events and contributing factors among pediatric cancer patients at Jimma University medical center, Southwest Ethiopia

BACKGROUND

The characteristics and incidence of adverse drug events (ADEs) among pediatric cancer patients in developing countries have not been well characterized. ADEs & medication errors associated with cancer chemotherapy in children need to be analyzed on their incidence and severity. The purpose of this study was hence, to assess the incidence of adverse drug events and contributing factors among pediatric cancer patients at Jimma university medical center, Jimma, Ethiopia.

METHOD

A prospective observational method was used to study adverse drug events in pediatrics admitted to the pediatric oncology unit of Jimma University medical center between October and December 2020. The ADEs were identified using multifaceted approaches involving daily chart review, interviews of Parents/caregivers (and/or children themselves), attendance at ward rounds, and voluntary staff reports. Both univariate and multivariate logistic regression were used to assess the predictors of the identified ADEs. Those factors that showed association at p-value < 0.25 in the univariate analysis were added to the backward multivariate logistic regression model and the significant association was checked at p-value < 0.05.

RESULT

A total of 73 (46 male and 27 female) patients were included in the study. A total of 466 ADEs were identified with an incidence of 638.36 ADEs per 100 patients, 38.35 ADEs per 100 patient days, and 2.34 ADEs per chemotherapy cycle. The most common ADEs were hematologic toxicities (anemia 55(11.8%), neutropenia 52(11.16%) & thrombocytopenia 31(6.65%)), and gastrointestinal effects (nausea 46(9.87%), vomiting 46(9.87%), anorexia 41(8.8%). Out of 466 ADEs, 150 (32.19%) were classified as common terminology criteria for adverse events (CTCAE) as Grade 1, 199 (42.70%) as Grade 2, 64(13.73%) as Grade 3, 48(10.30%) as grade 4 and 5(1.07%) as Grade 5. Severe acute malnutrition (SAM) is the most common comorbidity present, 20(27.40%) followed by pneumonia, 4(5.50%). Presence of comorbidity (AOR 12.700, CI 1.978-81.549), cancer type (AOR 13.332, CI 3.288-54.059), use of 4 or more chemotherapy drugs (AOR 6.179, CI 1.894-20.165) and length of hospital stay more than 8 days (AOR 5.367, CI 1.167-24.684) were associated with the risk of developing grades 3 and 4 ADEs.

CONCLUSION

Adverse drug events were common in the pediatric oncology ward of JUMC. In particular, children with multiple chemotherapy drugs and those with the comorbid condition were at greater risk for adverse drug events.

Computational Approach for Rational Design of Fusion Uricase with PAS Sequences

Tumor lysis syndrome is a life-threatening condition for humans due to the lack of urate oxidase. In this study, several variants of PASylated uricase from the Aspergillus flavus species were analyzed computationally to find the appropriate fusions to solve short half-life and stability concern. The Ab initio method was performed using Rosetta software to structurally characterize the PAS sequences. The 3D structures of fusions were predicted for fused C- or N-terminally PAS sequences in different length to the uricase. The refinement and energy minimization steps revealed that physicochemical and conformational properties of fusions improved while the structures possessed prolonged PAS sequences. Molecular docking results showed that the highest binding affinity to uric acid belonged to uricase-PAS1-100 by the formation of six hydrogen and four non-hydrogen bonds. Altogether, the results indicated that the PASylation process would be promising upon the production of urate oxidase with improved solubility and stability.

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.

Tumour lysis syndrome in children: experience of last decade

The strategy against tumour lysis syndrome (TLS) had been hyperhydration, urine alkalinization, and allopurinol. Recently, rasburicase was added to the armament against this life-threatening condition. In Korea, rasburicase is used as a rescue therapy for cases with allopurinol-resistant hyperuricemia, because of the restriction by the National Health Insurance. We reviewed our experiences to re-assess the risk factors of TLS and the efficacy of rasburicase. Medical records were retrospectively reviewed for 396 children who were diagnosed as positive with acute leukemia and non-Hodgkin lymphoma between the years 2000 and 2009. The risk factors for TLS were analyzed statistically, and those before and after the availability of rasburicase were compared. Sixty eight patients (17.2%) had TLS. Multivariate analysis showed that pre-chemotherapy hypophosphatemia was a risk factor for TLS, in addition to the known risk factors of hyperuricemia and high lactate dehydrogenase concentration. The availability of rasburicase as a rescue therapy did not negate the importance of uric acid as a risk factor of TLS. Rasburicase as a second line treatment for intractable hyperuricemia was not effective in reducing the incidence of TLS. Pre-chemotherapy hypophosphatemia was a significant independent risk factor for TLS.

The clinical management of tumour lysis syndrome in haematological malignancies

Tumour lysis syndrome (TLS) is caused by the disintegration of malignant cells, usually following the instigation of chemotherapy, although it may already be established at the time of initial presentation in a minority of cases. As a direct consequence of malignant cell breakdown, intracellular ions, proteins, nucleic acids and their metabolites are released into the plasma causing the characteristic metabolic abnormalities of TLS; hyperuricaemia, hyperkalaemia, hyperphosphataemia and hypocalcaemia. In many cases the release of large amounts intracellular contents is so abrupt that the normal homeostatic mechanisms are rapidly overwhelmed and without prompt, effective management, the clinical effects of TLS soon become apparent.

Cytokine-associated neutrophil extracellular traps and antinuclear antibodies in Plasmodium falciparum infected children under six years of age

BACKGROUND

In Plasmodium falciparum-infected children, the relationships between blood cell histopathology, blood plasma components, development of immunocompetence and disease severity remain poorly understood. Blood from Nigerian children with uncomplicated malaria was analysed to gain insight into these relationships. This investigation presents evidence for circulating neutrophil extracellular traps (NETs) and antinuclear IgG antibodies (ANA). The presence of NETs and ANA to double-stranded DNA along with the cytokine profiles found suggests autoimmune mechanisms that could produce pathogenesis in children, but immunoprotection in adults.

METHODS

Peripheral blood smear slides and blood samples obtained from 21 Nigerian children under six years of age, presenting with uncomplicated malaria before and seven days after initiation of sulphadoxine-pyrimethamine (SP) treatment were analysed. The slides were stained with Giemsa and with DAPI. Levels of the pro-inflammatory cytokines IFN-gamma, IL-2, TNF, CRP, and IL-6, select anti-inflammatory cytokines TGF-beta and IL-10, and ANA were determined by immunoassay.

RESULTS

The children exhibited circulating NETs with adherent parasites and erythrocytes, elevated ANA levels, a Th2 dominated cytokine profile, and left-shifted leukocyte differential counts. Nonspecific ANA levels were significant in 86% of the children pretreatment and in 100% of the children seven days after SP treatment, but in only 33% of age-matched control samples collected during the season of low parasite transmission. Levels of ANA specific for dsDNA were significant in 81% of the children both pre-treatment and post treatment.

CONCLUSION

The results of this investigation suggest that NET formation and ANA to dsDNA may induce pathology in falciparum-infected children, but activate a protective mechanism against falciparum malaria in adults. The significance of in vivo circulating chromatin in NETs and dsDNA ANA as a causative factor in the hyporesponsiveness of CpG oligonucleotide-based malaria vaccines is discussed.

Anti-cancer PEG-enzymes: 30 years old, but still a current approach

PEGylation (i.e. the covalent link of PEG strands) is a well known technique used to improve pharmaceutical properties of bioactive proteins and peptides. Even in cancer therapy some proteins, in particular enzymes, can find many applications, because of their antiproliferative action or ability to reduce side effects of chemotherapies, but to do so they need to be properly formulated. Unfortunately, formulation alone can not fulfil all the requirements to yield a safe and successful protein preparation for therapeutic applications. In particular, for many proteins fast clearance from the body and potential immunogenicity are severe limitations, which can not be easily overcome without taking into consideration a purposely designed drug delivery system. Among the approaches in the field of drug delivery, PEGylation has so far been the best choice for protein delivery. Here, we describe some examples of PEGylated enzymes useful in antitumoral therapies and the most recent advances in this field.

Avoiding Dialysis in Tumour Lysis Syndrome: Is Urate Oxidase Effective? – A Case Report and Review of Literature

Introduction: Hyperuricaemia in tumour lysis syndrome (TLS) can cause acute renal failure (ARF), necessitating dialysis. Recombinant urate oxidase (rasburicase) converts uric acid to soluble allantoin, which is excreted easily. Case Report: An 8-year-old boy with stage 3 Burkitt’s lymphoma, TLS was successfully treated with hyper-hydration, diuretics and rasburicase, without dialysis. This is the first paediatric case in Kandang Kerbau Women’s & Children’s Hospital (KKH) in which rasburicase was used. We review the literature on the effectiveness of urate oxidase in avoiding dialysis in TLS. Treatment and Outcome: Our patient developed rapidly rising serum uric acid (SUA) and progressive renal impairment. Hyper-hydration and rasburicase (0.2mg/kg) were administered. SUA rapidly decreased from 1308 to 437 mmol/L within 12 hours. Urate oxidase has shown better results than allopurinol. There was a need for dialysis in 0.4% to 1.7% of patients with haematological malignancies given rasburicase, compared to 20% in patients given allopurinol. Conclusions: Rasburicase can reverse renal insufficiency. Though expensive, it may be cost-effective by lowering incidence of dialysis, shortening the duration of intensive care and hospitalisation, allowing early chemotherapy. Key words: Acute renal failure, Hyperuricemia, Recombinant urate oxidase, Renal insufficiency

Rasburicase (Elitek): a novel agent for tumor lysis syndrome

The overall incidence of tumor lysis syndrome in adults is not well defined, and its occurrence can be unpredictable. Several strategies are available for the prevention and treatment of tumor lysis syndrome, with rasburicase being the most recent. Rasburicase is a recombinant urate oxidase enzyme approved for use by the Food and Drug Administration in patients who are at risk of developing tumor lysis syndrome or for the management of elevated uric acid levels. Clinical trials have demonstrated rasburicase to be effective in both the pediatric and adult populations, although the drug is currently indicated only for use in the pediatric population. Adverse effects associated with rasburicase can be significant, ranging from anaphylactic reactions to methemoglobinemia. To ensure accuracy of uric acid test results, special laboratory handling procedures must be followed while patients receive rasburicase. Compared with allopurinol and intravenous sodium bicarbonate, rasburicase is costly, and therefore judicious use of the medication is warranted.

Serum uric acid-lowering therapies: Where are we heading in management of hyperuricemia and the potential role of uricase

Although allopurinol has been available for approximately 50 years, hyperuricemia and its sequelae are not only prevalent, but the incidence and costs associated with this disorder continue to increase. However, several new therapies have been developed. Recombinant urate oxidase has been useful in the treatment of tumor lysis hyperuricemia, and pegylated urate oxidase shows promise in patients with hyperuricemia and gout. Febuxostat and Y-700 are new oral xanthine oxidase inhibitors that are in human clinical trials. Tailoring of antilipid therapy in selected hyperuricemic and hyperlipidemic patients with fenofibrate may be of benefit in lowering blood cholesterol and uric acid levels. Similarly, treatment of selected hyperuricemic patients who also are hypertensive with losartan or amlodipine may be beneficial in lowering blood pressure and hyperuricemia. Despite these advances, new treatments for hyperuricemia are needed.

The enzyme as drug: application of enzymes as pharmaceuticals

Enzymes as drugs have two important features that distinguish them from all other types of drugs. First, enzymes often bind and act on their targets with great affinity and specificity. Second, enzymes are catalytic and convert multiple target molecules to the desired products. These two features make enzymes specific and potent drugs that can accomplish therapeutic biochemistry in the body that small molecules cannot. These characteristics have resulted in the development of many enzyme drugs for a wide range of disorders.