The use of steroids to prevent cutaneous reactions to benznidazole in patients with Chagas disease

Trypanocidal treatment of Chagas disease

Chagas disease is a neglected parasitosis caused by the protozoan parasite Trypanosoma cruzi. This infection is present in most Latin American countries, although, due to migratory movements, it is a growing cause for concern in non-endemic countries. The only two drugs currently available for its treatment-benznidazole and nifurtimox-were marketed 50 years ago. While they are very effective for acute and recent infection, and for the prevention of maternofoetal transmission, their efficacy declines in people who have chronic infection, especially those older than 18 years of age. In the presence of visceral involvement, parasiticidal treatment is of little or no value. The safety profile of both drugs is far from ideal, with frequent adverse events and high rates of drug discontinuation, mainly in adults. So far, new drugs and new strategies have not been shown to improve the results of the current nitroimidazoles, although the results are promising. In this review, we focus on the aspects that allow clinicians to make the best use of currently available drugs. In addition, we discuss new therapeutic options and ongoing research in the field.

Benznidazole for the treatment of Chagas disease

INTRODUCTION

Chagas disease affects 6-7 million people, mainly in the Americas, and benznidazole is one of the two therapeutic options available. Trypanocide treatment aims to eliminate the parasite from the body to prevent the establishment or progression of visceral damage, mainly cardiac and/or digestive. Remarkably, it helps interrupt vertical transmission when administered to women of childbearing age.

AREAS COVERED

We discuss the basic and scarce data regarding chemical, pharmacokinetic, and pharmacodynamic structure. We also collect the most important data from previous phase II and III studies, as well as studies currently underway and upcoming. We reflect on the main indications for treatment and its challenges, such as the profile of adverse effects in adults, the pharmaceutical formulations, the search for reliable biomarkers, as well as regulatory aspects and access barriers. Alternative strategies such as shorter regimens, lower doses, and fixed doses are currently being evaluated to improve access and the safety profile of this treatment.

EXPERT OPINION

Benznidazole is likely to continue to be the drug of choice for Chagas disease in the coming years. However, it would probably be with a different treatment scheme.

Trypanocidal treatment of Chagas disease

Chagas disease is a neglected parasitosis caused by the protozoan parasite Trypanosoma cruzi. This infection is present in most Latin American countries, although, due to migratory movements, it is a growing cause for concern in non-endemic countries. The only two drugs currently available for its treatment-benznidazole and nifurtimox-were marketed 50 years ago. While they are very effective for acute and recent infection, and for the prevention of maternofoetal transmission, their efficacy declines in people who have chronic infection, especially those older than 18 years of age. In the presence of visceral involvement, parasiticidal treatment is of little or no value. The safety profile of both drugs is far from ideal, with frequent adverse events and high rates of drug discontinuation, mainly in adults. So far, new drugs and new strategies have not been shown to improve the results of the current nitroimidazoles, although the results are promising. In this review, we focus on the aspects that allow clinicians to make the best use of currently available drugs. In addition, we discuss new therapeutic options and ongoing research in the field.

Does Progressive Introduction of Benznidazole Reduce the Chance of Adverse Events in the Treatment of Chagas Disease?

In this retrospective cohort study, we aimed to assess whether introducing benznidazole at escalating doses reduces the probability of adverse events or treatment discontinuation compared with a full-dose scheme. We collected data from patients who had chronic Trypanosoma cruzi infection and underwent treatment from July 2008 to January 2017 in a referral center in Madrid. Dose was adjusted to body weight (5 mg/kg/day), with treatment introduction with full dose or escalating dose according to local consensus and protocols. Among the 62 patients treated, benznidazole was introduced at full dose in 28 patients and on escalating dose in the remaining 34. We found no statistical differences in the number of adverse events, treatment discontinuations, days of treatment, or sociodemographic profiles. There is insufficient evidence to support escalating dose as a strategy for reducing the adverse effects of benznidazole. Further research is needed to evaluate this approach.

Comparison of the toxicity of two treatment schemes with benznidazole for chronic Chagas disease: a prospective cohort study in two Spanish referral centres

OBJECTIVES

Chagas disease (CD) treatment is limited to two therapeutic options: benznidazole (generally the first option in Spain) and nifurtimox. Both drugs present high rates of adverse reactions and treatment discontinuation and there is no consensus regarding the most effective administration schedule for benznidazole or how to prevent and manage treatment toxicity. We aim to compare the tolerability and treatment discontinuation rate between two different treatment schemes with benznidazole.

METHODS

This was a prospective observational study of adult patients with CD, enrolled from January 2014 to March 2018 in two referral centres in Madrid (Spain). Participants were treated either with benznidazole 5 mg/kg/day (full dose) over 60 days (benznidazole standard dose scheme (BSD)), or with an escalating dose lasting 5 days up to a maximum of 300 mg/day (benznidazole increasing dose scheme (BID)).

RESULTS

471 patients were analysed: 201 in the BSD group and 270 in the BID group. There were no significant differences regarding age (40.4 (SD 8.7) vs 41 (SD 8.2) years), sex (74.1% (149/201) vs 68.5% (185/270) women), weight (69.4 (SD 12.8) vs 68.9 (SD 11) kg) or nationality (97.5% (196/201) vs 96.7% (261/270) Bolivians) between groups. There were also no differences in adverse reactions rate (55.2% (111/201) vs 55.6% (150/270)), number of adverse reactions per patient, adverse reactions type (except for arthralgias and myalgias which occurred more frequently in the BID group (0% (0/111) BSD vs 8% (12/150) BID; p 0.002)) and degree and time to first adverse reactions. There was significantly more treatment discontinuation (49.8% (100/201) vs 33.0% (89/270); p <0.001) in the BSD group, but not during the first 30 days of treatment (32.3% (65/201) vs 25.6% (69/270); p 0.08).

CONCLUSION

The use of increasing doses of benznidazole for 5 days and a maximum dose of 300 mg, does not significantly improve drug tolerability. However, while the treatment discontinuation rates were similar during the first 30 days of treatment, it may improve the treatment completion rate at 60 days.

Safety Profile of Benznidazole in the Treatment of Chronic Chagas Disease: Experience of a Referral Centre and Systematic Literature Review with Meta-Analysis

INTRODUCTION

Benznidazole is the preferred drug for treatment of Chagas disease. However, it is toxic and of limited value in chronic infection.

OBJECTIVE

We aimed to estimate the rates of and factors related to adverse reactions (ARs) to benznidazole and treatment discontinuations (TDs).

METHODS

A meta-analysis was performed using an electronic search of the published literature with no language restrictions until June 2017. Prospective studies were included of chronically infected patients in which at least one treatment arm included benznidazole. Data were added from a prospective cohort of patients with Chagas disease at our centre (January 2007-June 2017). Weighted rates of ARs and TDs were estimated, and potentially related factors were analysed.

RESULTS

Some 413 studies were found, from which we chose 42 (nine clinical trials and 33 observational studies, including ours), comprising data for 7822 patients. The weighted rate of ARs to benznidazole was 44.1% (95% confidence interval [CI] 37.2-51.2). ARs were more frequent in adults than in children (51.6 vs. 24.5%), with the most common being skin reactions (34%), gastrointestinal complaints (12.6%) and neurological symptoms (11.5%). Grade 4 ARs were recorded in 3% of cases. The weighted rate of TDs was 11.4% (95% CI 8.5-14.5); TDs were more frequent in adults than in children (14.2 vs. 3.8%). In our cohort, only female sex was related to an increased rate of ARs but not to TDs.

CONCLUSION

Benznidazole had a poor tolerability profile, with a high incidence of TDs, especially in adult patients and women. Optimised dosing schedules and/or new drugs are urgently needed.

Benznidazole treatment safety: the Médecins Sans Frontières experience in a large cohort of Bolivian patients with Chagas' disease

Background

Up to half of patients with Chagas' disease under benznidazole treatment present adverse drug reactions (ADRs) and up to one-third do not complete standard treatment.

Objectives

To verify the incidence and possible factors associated with the suspension of benznidazole treatment in a large cohort of patients.

Methods

We included 2075 patients treated with benznidazole during the projects managed by the medical humanitarian organization Doctors Without Borders (Médecins Sans Frontières) in Bolivia from 2009 to 2013. Benznidazole treatment was provided two or three times per day for ∼60 days at 5-7.5 mg/kg/day. A multiple logistic regression model was developed to evaluate the factors associated with permanent suspension of benznidazole treatment.

Results

Permanent benznidazole treatment suspension occurred in 211 patients (10.2%) and the average time until permanent treatment suspension was 23 days. Multifactorial analysis revealed that female sex (adjusted OR = 1.70), moderate ADRs (adjusted OR = 10.57), mild ADRs (adjusted OR = 1.69) and skin disorders (adjusted OR = 4.18) were significantly associated with the permanent suspension of benznidazole treatment. Women with mild or moderate skin ADRs presented a probability of treatment interruption of 18.6% and 59.0%, respectively.

Conclusions

Benznidazole treatment was safe and a large proportion of patients were able to complete a full course of benznidazole treatment under close treatment surveillance. Female sex, skin disorders and mild and moderate ADRs were independently associated with the permanent suspension of benznidazole treatment. In particular, women with moderate skin ADRs had the highest risk of benznidazole treatment interruption.

Chagas disease

Chagas disease is an anthropozoonosis from the American continent that has spread from its original boundaries through migration. It is caused by the protozoan Trypanosoma cruzi, which was identified in the first decade of the 20th century. Once acute infection resolves, patients can develop chronic disease, which in up to 30-40% of cases is characterised by cardiomyopathy, arrhythmias, megaviscera, and, more rarely, polyneuropathy and stroke. Even after more than a century, many challenges remain unresolved, since epidemiological control and diagnostic, therapeutic, and prognostic methods must be improved. In particular, the efficacy and tolerability profile of therapeutic agents is far from ideal. Furthermore, the population affected is older and more complex (eg, immunosuppressed patients and patients with cancer). Nevertheless, in recent years, our knowledge of Chagas disease has expanded, and the international networking needed to change the course of this deadly disease during the 21st century has begun.

Evaluation of cytokine profile and HLA association in benznidazole related cutaneous reactions in patients with Chagas disease

BACKGROUND

Benznidazole is the drug of choice for Chagas disease. The major drawback of this drug is the high adverse events rate, being cutaneous reactions the most frequent one, leading to definitive withdrawal of treatment in 15%-30% of patients.

METHODS

Prospective observational study where adult Chagas disease patients accepting to receive benznidazole (100 mg/8 hours for 60 days) were included. The objective was to characterize the skin toxicity of benznidazole in patients with Chagas disease, determine the serum cytokine profile, and evaluate the potential association with specific HLA alleles and benznidazole concentration. Serum cytokine levels were measured at day 0, 15, and 60 of treatment. Class I and II HLA alleles were determined. When cutaneous reaction was detected, a skin biopsy was performed. Serum benznidazole concentration was determined at the time of cutaneous reaction, or at day 15 of treatment.

RESULTS

Fifty-two patients were included, 20(38.5%) had cutaneous reaction, and median time of appearance was 9 days. Skin biopsies showed histopathological findings consistent with drug eruption. Patients with cutaneous drug-reaction had higher proportion of eosinophilia during treatment, and higher interleukin (IL)-5 and IL-10 serum concentrations at day 15 of treatment than those without cutaneous reaction. Treatment interruption (that included moderate-severe cutaneous reactions) was more frequent in patients carrying HLA-B*3505 allele (45.5% vs 15.4%, P = .033). No differences in benznidazole serum concentration were found.

CONCLUSIONS

Benznidazole related cutaneous reaction rate is high, and it was produced by a delayed hypersensitivity reaction with a Th2 response. Carrying HLA-B*3505 allele could be associated with moderate-severe cutaneous reaction.

Old and new challenges in Chagas disease

Chagas disease, caused by the parasite Trypanosoma cruzi, is a neglected disease, which can lead to cardiomyopathy, arrhythmias, megaviscera, and more rarely, polyneuropathy in up to 30-40% of patients around 20 to 30 years after acute infection. Although it is endemic in the Americas, global population movements mean that it can be located wherever migrants from endemic areas settle. The disease was first described 100 years ago and still challenges clinicians worldwide, since diagnostic, therapeutic, and prognostic methods remain insufficient. Furthermore, factors such as HIV co-infection, immunosuppressive drugs, transplantation, and neoplastic disease can alter the natural course of the infection. We present the case of a Bolivian woman with chronic T cruzi infection diagnosed at our clinic in Madrid, Spain, who subsequently developed non-Hodgkin lymphoma. Our report illustrates the challenges of an increasingly common infection seen in non-endemic countries, and highlights both daily management dilemmas and associated difficulties that arise.