Massive arsenic poisoning--effect of hemodialysis and dimercaprol on arsenic kinetics

Phase I studies of darinaparsin in patients with relapsed or refractory peripheral T-cell lymphoma: a pooled analysis of two phase I studies conducted in Japan and Korea

OBJECTIVE

Two phase I studies of darinaparsin including Japanese and Korean patients with relapsed/refractory peripheral T-cell lymphoma were performed to evaluate its safety (primary purpose), efficacy and pharmacokinetic profile (ClinicalTrials.gov: NCT01435863 and NCT01689220).

METHODS

Patients received intravenous darinaparsin for 5 consecutive days at 200 mg/m2/day in 4-week cycles, 300 mg/m2/day in 4-week cycles or 300 mg/m2/day in 3-week cycles.

RESULTS

Seventeen Japanese and 6 Korean patients were enrolled and treated. Drug-related adverse events developed in 18 patients (78%). Dose-limiting toxicity, grade 3 hepatic dysfunction, was reported on Day 15 of cycle 1 in 1 Japanese patient who received 300 mg/m2/day. The most common drug-related, grade ≥ 3 adverse events were lymphopenia (9%), neutropenia (9%) and thrombocytopenia (9%). No deaths occurred. In 14 evaluable patients, 1 and 3 patients had complete response and partial response, respectively. The plasma concentration-time profiles of arsenic, a surrogate marker for darinaparsin, were similar between Japanese and Korean patients. No significant difference was found in its pharmacokinetic profile.

CONCLUSIONS

These data indicate the good tolerability and potential efficacy of darinaparsin in patients with relapsed/refractory peripheral T-cell lymphoma. Darinaparsin 300 mg/m2/day for 5 consecutive days in 3-week cycles is the recommended regimen for phase II study.

Arsenic intoxication: general aspects and chelating agents

Arsenic (As) is widely used in the modern industry, especially in the production of pesticides, herbicides, wood preservatives, and semiconductors. The sources of As such as contaminated water, air, soil, but also food, can cause serious human diseases. The complex mechanism of As toxicity in the human body is associated with the generation of free radicals and the induction of oxidative damage in the cell. One effective strategy in reducing the toxic effects of As is the usage of chelating agents, which provide the formation of inert chelator–metal complexes with their further excretion from the body. This review discusses different aspects of the use of metal chelators, alone or in combination, in the treatment of As poisoning. Consideration is given to the therapeutic effect of thiol chelators such as meso-2,3-dimercaptosuccinic acid, sodium 2,3-dimercapto-1-propanesulfonate, 2,3-dimercaptopropanol, penicillamine, ethylenediaminetetraacetic acid, and other recent agents against As toxicity. The review also considers the possible role of flavonoids, trace elements, and herbal drugs as promising natural chelating and detoxifying agents.

Treatment of lead and arsenic poisoning in anuric patients - a case report and narrative review of the literature

Background

Heavy metal poisoning can cause debilitating illness if left untreated, and its management in anuric patients poses challenges. Literature with which to guide clinical practice in this area is rather scattered.

Case presentation

We present a case of symptomatic lead and arsenic poisoning from use of Ayurvedic medicine in a 28-year-old man with end-stage kidney disease on chronic hemodialysis. We describe his treatment course with chelating agents and extracorporeal blood purification, and review the relevant literature to provide general guidance.

Conclusion

Cumulative clinical experience assists in identifying preferred chelators and modalities of extracorporeal blood purification when managing such patients. However, a larger body of real-world or clinical trial evidence is necessary to inform evidence-based guidelines for the management of heavy metal poisoning in anuric patients.

Disturbances of trace element metabolism in ESRD patients receiving hemodialysis and hemodiafiltration

Introduction

Accumulation of trace elements occurs in conditions of decreased kidney function. In some conditions, increased trace elements can have toxic features. On the other hand, studies are showing that concentration of some trace elements could be decreased in ERSD patients as well. The most important factor affecting trace element concentration in ERSD patients is the degree of renal failure and the usage of replacement therapy.

Materials and methods

We analyzed the trace elements’ (boron, aluminum, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, rubidium, strontium, cadmium, cesium, barium and lead) concentration in the whole blood of 41 ESRD patients who were treated with hemodialysis and hemodiafiltration and also of 61 healthy blood donors. In addition, comparison of trace element blood levels of patients receiving hemodialysis and hemofiltration was carried out. Whole blood trace element concentration was determined using inductive coupled plasma mass-spectrometry (ICPMS).

Results

Levels of boron, aluminum, vanadium, chromium, manganese, zinc, strontium, cadmium, barium and lead were significantly increased in ESRD patients. Significantly decreased levels were observed for nickel, arsenic, selenium and rubidium. Blood levels of cobalt, copper, cadmium and lead in hemodialysis patients were significantly higher compared to patients receiving hemodiafiltration.

Conclusions

ESRD is accompanied with serious and multidirectional changes of trace element blood levels. The highest degree of blood level increases were observed for nonessential and toxic trace elements. Disorders of essential trace elements were manifested in a minor degree. Besides this, there were observed differences of trace element concentrations between ESRD patients receiving hemodialysis and hemo-diafiltration.

A phase I clinical trial of darinaparsin in patients with refractory solid tumors

PURPOSE

Darinaparsin, an organic arsenic, targets essential cell survival pathways. We determined the dose-limiting toxicity (DLT) and maximum tolerated dose of darinaparsin in patients with advanced cancer.

EXPERIMENTAL DESIGN

Patients with solid malignancies refractory to conventional therapies were treated with i.v. darinaparsin daily for 5 days every 4 weeks. The starting dose (78 mg/m(2)) escalated to 109, 153, 214, 300, 420, and 588 mg/m(2). A conventional "3 + 3" design was used.

RESULTS

Forty patients (median age, 61.5 years; median number of prior therapies, 5) received therapy; 106 cycles were given (median, 2; range, 1-12). Twenty patients reported no drug-related toxicities. No DLTs were reported at a dose of <420 mg/m(2). At 588 mg/m(2), two of four patients developed DLTs, including grade 3 altered mental status and ataxia. Of four patients treated at the de-escalated dose of 500 mg/m(2), one developed similar toxicities. De-escalating the dose to 420 mg/m(2) (n = 8) resulted in two neurologic DLTs. Further de-escalation to 300 mg/m(2) (n = 3) resulted in no drug-related toxicities. Arsenic plasma levels peaked on treatment day 3, plateaued on day 5, and returned to baseline on day 7. Plasma levels varied within cohorts but increased with increasing doses. The median plasma arsenic half-life was 16.2 hours. Seven (17.5%) patients had stable disease for > or =4 months (median, 6; range, 4-11), including 4 of 17 with colorectal and 2 of 3 with renal cancer.

CONCLUSIONS

The recommended dose for phase II trials is 300 mg/m(2) i.v. given daily for 5 days every 4 weeks.

[Arsenic poisoning: a special gastroenteritis...]

Arsenic (As) intoxication is nowadays extremely rare. Two cases of acute and chronic As criminal poisoning leading to death of a couple of retired people, are reported. Clinical presentation was simulating a gastro-enteritidis with fast evolution to refractory shock. Toxicological analysis confirmed this diagnostic, with respectively blood As concentrations at 579 and 21 765 microg/l for our two patients.

Un cas de neuropathie mimant un syndrome de Guillain-Barré après une intoxication à l’arsenic

INTRODUCTION

Chronic arsenic toxicity is a global health problem affecting millions of people. Acute arsenic poisoning is less frequent and it is most often lethal. Therefore, its consequences are not well known, more precisely its neurological consequences.

OBSERVATION

We report a case of Guillain-Barré-like syndrome and encephalopathy after acute arsenical poisoning in a 50 year-old man. After 4 month follow-up, the improvement was slow and limited with persistent motor and proprioceptive deficits.

DISCUSSION

The most frequent neurological complication induced by acute arsenical poisoning is a distal, symmetrical, sensory, axonal polyneuropathy. Yet the clinical course and the electrophysiological findings may also suggest a Guillain-Barré like syndrome. Moreover, the chelating is not very effective on the neurological complications.

CONCLUSION

Any discrepancies in the clinical course of a Guillain-Barré syndrome shall lead to reconsider the diagnosis. The association of gastro-intestinal disorders, skin lesions, and encephalopathy and mood disorders leads to discuss intoxication with heavy metal and more precisely with arsenic. Moreover, the chelating is not very effective on the neurological complications.

Heavy Metal Poisoning: Clinical Presentations and Pathophysiology

Humans have had a long and tumultuous relationship with heavy metals. Their ubiquitous nature and our reliance on them for manufacturing have resulted at times in exposures sufficient to cause systemic toxicity. Their easy acquisition and potent toxicity have also made them popular choices for criminal poisonings. This article examines the clinical manifestation and pathophysiology of poisoning from lead, mercury, arsenic, and thallium.

Massive acute arsenic poisonings

Arsenic poisonings are still important in the field of toxicology, though they are not as frequent as about 20-30 years ago. In this paper, the arsenic concentrations in ante- and post-mortem materials, and also forensic and anatomo-pathological aspects in three cases of massive acute poisoning with arsenic(III) oxide (two of them with unexplained criminalistic background, in which arsenic was taken for amphetamine and one suicide), are presented. Ante-mortem blood and urine arsenic concentrations ranged from 2.3 to 6.7 microg/ml, respectively. Post-mortem tissue total arsenic concentrations were also detected in large concentrations. In case 3, the contents of the duodenum contained as much as 30.1% arsenic(III) oxide. The high concentrations of arsenic detected in blood and tissues in all presented cases are particularly noteworthy in that they are very rarely detected at these concentrations in fatal arsenic poisonings.

Acute arsenic poisoning in two siblings

We report a case series of acute arsenic poisoning of 2 siblings, a 4-month-old male infant and his 2-year-old sister. Each child ingested solubilized inorganic arsenic from an outdated pesticide that was misidentified as spring water. The 4-month-old child ingested a dose of arsenic that was lethal despite extraordinary attempts at arsenic removal, including chelation therapy, extracorporeal membrane oxygenation, exchange transfusion, and hemodialysis. The 2-year-old fared well with conventional therapy.

Acute arsenic poisoning treated by intravenous dimercaptosuccinic acid (DMSA) and combined extrarenal epuration techniques

Arsenic poisoning was diagnosed in a 26-year-old man who had been criminally intoxicated over the last two weeks preceding admission by the surreptitious oral administration of probably 10 g of arsenic trioxide (As2O3). The patient developed severe manifestations of toxic hepatitis and pancreatitis, and thereafter neurological disorders, respiratory distress, acute renal failure, and cardiovascular disturbances. In addition to supportive therapy, extrarenal elimination techniques and chelating agents were used. Dimercaprol (BAL) and dimercaptosuccinic acid (DMSA or succimer) were used simultaneously as arsenic chelating agents for two days, and thereafter DMSA was used alone. DMSA was administered by intravenous (20 mg/kg/d for five days, then 10 mg/kg/d for six days) and intraperitoneal route. Intravenous DMSA infusion was well tolerated and resulted in an increase in arsenic blood concentration immediately after the infusion. Continuous venovenous hemofiltration combined with hemodialysis, and peritoneal dialysis were proposed to enhance arsenic elimination. It was calculated that over an 11-day period 14.5 mg arsenic were eliminated by the urine, 26.7 mg by hemodialysis, 17.8 mg by peritoneal dialysis, and 7.8 mg by continuous venovenous hemofiltration. These amounts appeared negligible with regard to the probable ingested dose. The patient died on day 26 from the consequences of multiple organ failure, with subarachnoid hemorrhage and generalized infection caused by Aspergillus fumigatus.