Safety, tolerability, efficacy and plasma concentrations of diethylcarbamazine and albendazole co-administration in a field study in an area endemic for lymphatic filariasis in India

Albendazole alone or in combination with microfilaricidal drugs for lymphatic filariasis

BACKGROUND

The Global Programme to Eliminate Lymphatic Filariasis recommends mass treatment of albendazole co-administered with the microfilaricidal (antifilarial) drugs diethylcarbamazine (DEC) or ivermectin; and recommends albendazole alone in areas where loiasis is endemic.

OBJECTIVES

To assess the effects of albendazole alone, and the effects of adding albendazole to DEC or ivermectin, in people and communities with lymphatic filariasis.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), Embase (OVID), LILACS (BIREME), and reference lists of included trials. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform and ClinicalTrials.gov to identify ongoing trials. We performed all searches up to 15 January 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and cluster-RCTs that compared albendazole to placebo or no placebo, or compared albendazole combined with a microfilaricidal drug to a microfilaricidal drug alone, given to people known to have lymphatic filariasis or communities where lymphatic filariasis was known to be endemic. We sought data on measures of transmission potential (microfilariae (mf) prevalence and density); markers of adult worm infection (antigenaemia prevalence and density, and adult worm prevalence detected by ultrasound); and data on clinical disease and adverse events.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the trials, evaluated the risks of bias, and extracted data. The main analysis examined albendazole overall, whether given alone or added to a microfilaricidal drug. We used data collected from all randomized individuals at time of longest follow-up (up to 12 months) for meta-analysis of outcomes. We evaluated mf density data up to six months and at 12 months follow-up to ensure that we did not miss any subtle temporal effects. We conducted additional analyses for different follow-up periods and whether trials reported on individuals known to be infected or both infected and uninfected. We analysed dichotomous data using the risk ratio (RR) with a 95% confidence interval (CI). We could not meta-analyse data on parasite density outcomes and we summarized them in tables. Where data were missing, we contacted trial authors. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 13 trials (12 individually-randomized and one small cluster-randomized trial) with 8713 participants in total. No trials evaluated population-level effects of albendazole in mass drug administration programmes. Seven trials enrolled people with a variety of inclusion criteria related to filarial infection, and six trials enrolled individuals from endemic areas. Outcomes were reported as end or change values. Mf and antigen density data were reported using the geometric mean, log mean and arithmetic mean, and reductions in density were variously calculated. Two trials discounted any increases in mf density in individuals at follow-up by setting any density increase to zero.For mf prevalence over two weeks to 12 months, albendazole alone or added to another microfilaricidal drug makes little or no difference (RR 0.95, 95% CI 0.85 to 1.07; 5027 participants, 12 trials, high-certainty evidence). For mf density there is no trend, with some trials reporting a greater reduction in mf density with albendazole and others a greater reduction with the control group. For mf density up to six months and at 12 months, we do not know if albendazole has an effect (one to six months: 1216 participants, 10 trials, very low-certainty evidence; at 12 months: 1052 participants, 9 trials, very low-certainty evidence).For antigenaemia prevalence between six to 12 months, albendazole alone or added to another microfilaricidal drug makes little or no difference (RR 1.04, 95% CI 0.97 to 1.12; 3774 participants, 7 trials, high-certainty evidence). For antigen density over six to 12 months, the trend shows little or no effect of albendazole; but we do not know if albendazole has an effect on antigen density (1374 participants, 5 trials, very low-certainty evidence). For adult worm prevalence detected by ultrasound at 12 months, albendazole added to a microfilaricidal drug may make little or no difference (RR 1.16, 95% CI 0.72 to 1.86; 165 participants, 3 trials, low-certainty evidence).For people reporting adverse events, albendazole makes little or no difference (RR 0.97, 95% CI 0.84 to 1.13; 2894 participants, 6 trials, high-certainty evidence).We also provide meta-analyses and GRADE tables by drug, as operationally this may be of interest: for albendazole versus placebo (4 trials, 1870 participants); for albendazole with DEC compared to DEC alone (8 trials, 3405 participants); and albendazole with ivermectin compared to ivermectin alone (4 trials, 3438 participants).

AUTHORS' CONCLUSIONS

There is good evidence that albendazole makes little difference to clearing microfilaraemia or adult filarial worms in the 12 months post-treatment. This finding is consistent in trials evaluating albendazole alone, or added to DEC or ivermectin. Trials reporting mf density included small numbers of participants, calculated density data variously, and gave inconsistent results.The review raises questions over whether albendazole has any important contribution to the elimination of lymphatic filariasis. To inform policy for areas with loiasis where only albendazole can be used, it may be worth conducting placebo-controlled trials of albendazole alone.

Adverse events following single dose treatment of lymphatic filariasis: Observations from a review of the literature

Background

WHO’s Global Programme to Eliminate Lymphatic Filariasis (LF) uses mass drug administration (MDA) of anthelmintic medications to interrupt LF transmission in endemic areas. Recently, a single dose combination of ivermectin (IVM), diethylcarbamazine (DEC), and albendazole (ALB) was shown to be markedly more effective than the standard two-drug regimens (DEC or IVM, plus ALB) for achieving long-term clearance of microfilaremia.

Objective and methods

To provide context for the results of a large-scale, international safety trial of MDA using triple drug therapy, we searched Ovid Medline for studies published from 1985–2017 that reported adverse events (AEs) following treatment of LF with IVM, DEC, ALB, or any combination of these medications. Studies that reported AE rates by treatment group were included.

Findings

We reviewed 162 published manuscripts, 55 of which met inclusion criteria. Among these, 34 were clinic or hospital-based clinical trials, and 21 were community-based studies. Reported AE rates varied widely. The median AE rate following DEC or IVM treatment was greater than 60% among microfilaremic participants and less than 10% in persons without microfilaremia. The most common AEs reported were fever, headache, myalgia or arthralgia, fatigue, and malaise.

Interpretation

Mild to moderate systemic AEs related to death of microfilariae are common following LF treatment. Post-treatment AEs are transient and rarely severe or serious. Comparison of AE rates from different community studies is difficult due to inconsistent AE reporting, varied infection rates, and varied intensity of follow-up. A more uniform approach for assessing and reporting AEs in LF community treatment studies would be helpful.

WHO’s Global Programme to Eliminate Lymphatic Filariais (LF) supports annual mass drug administration to over 400 million people in LF-endemic areas each year. Two drug combinations (either DEC or ivermectin, given with albendazole) have been recommended in most endemic areas. With the exception of well-described serious adverse events (AEs) occurring in patients with high level loiasis, severe AEs due to these medications are extremely rare. Mild to moderate AEs, however, are common, particularly in patients with active filarial infection. In this manuscript we synthesize published data on AEs following single-dose treatment of LF with ivermectin, DEC, or albendazole. This provides a background against which to compare the safety of triple drug therapy (ivermectin, DEC, and albendazole) recently endorsed by WHO, and provides a useful context for evaluating safety of new treatments for LF. The compiled data illustrate that transient, mild to moderate AEs following single-dose LF treatment are common in microfilaremic patients and are much less common in amicrofilaremic patients. They also show that passive surveillance for post-treatment AEs underestimates AE incidence and suggest that adherence to common reporting standards would improve the usefulness of AE reporting in filariasis studies.

Efficacy and tolerability of treatment with single doses of diethylcarbamazine (DEC) and DEC plus albendazole (ABZ) for three consecutive years in lymphatic filariasis: a field study in India

Lymphatic filariasis (LF) affects 73 countries, causes morbidity and impedes socioeconomic development. We had found no difference in safety and micro (Mf) and macro filarial action of single-dose diethylcarbamazine (DEC) and DEC + albendazole (ABZ) in an F01 study done in India (year 2000). There was a programmatic need to evaluate safety and efficacy of multiple annual treatments (F02). Subjects (155) from the F01 study, meeting inclusion-exclusion criteria, were enrolled in F02 and treated with further two annual doses of DEC or DEC + ABZ. Efficacy was evaluated for Mf positivity by peripheral smear (PS) and nucleopore (NP) filter, circulating filarial antigen (CFA) and filarial dance sign (FDS) positivity and Mf count at yearly follow-up. Safety was assessed for 5 days after drug administration. Total of 139 subjects evaluated for efficacy (69 DEC and 70 DEC + ABZ group). Mf positivity prevalence declined progressively by 95% (PS), 66% (NP), and 95% (PS) and 86% (NP); CFA positivity prevalence declined by 15% and 9%; FDS by 100% each; Mf count declined by 75.5 and 76.9% with three annual treatment of DEC and DEC + ABZ, respectively. Addition of ABZ did not show any advantage over DEC given as three annual rounds for LF. DEC and DEC + ABZ were well tolerated. There was no correlation between result of CFA and FDS, (both claimed to be indicative of adult worm). Analysis of published studies and our data indicate that macrofilaricidal effect of DEC/DEC + ABZ may be seen in children and not adults, with three or more annual dosing.

Mathematical modelling of lymphatic filariasis elimination programmes in India: required duration of mass drug administration and post-treatment level of infection indicators

Background

India has made great progress towards the elimination of lymphatic filariasis. By 2015, most endemic districts had completed at least five annual rounds of mass drug administration (MDA). The next challenge is to determine when MDA can be stopped. We performed a simulation study with the individual-based model LYMFASIM to help clarify this.

Methods

We used a model-variant for Indian settings. We considered different hypotheses on detectability of antigenaemia (Ag) in relation to underlying adult worm burden, choosing the most likely hypothesis by comparing the model predicted association between community-level microfilaraemia (Mf) and antigenaemia (Ag) prevalence levels to observed data (collated from literature). Next, we estimated how long MDA must be continued in order to achieve elimination in different transmission settings and what Mf and Ag prevalence may still remain 1 year after the last required MDA round. The robustness of key-outcomes was assessed in a sensitivity analysis.

Results

Our model matched observed data qualitatively well when we assumed an Ag detection rate of 50 % for single worm infections, which increases with the number of adult worms (modelled by relating detection to the presence of female worms). The required duration of annual MDA increased with higher baseline endemicity and lower coverage (varying between 2 and 12 rounds), while the remaining residual infection 1 year after the last required treatment declined with transmission intensity. For low and high transmission settings, the median residual infection levels were 1.0 % and 0.4 % (Mf prevalence in the 5+ population), and 3.5 % and 2.0 % (Ag prevalence in 6–7 year-old children).

Conclusion

To achieve elimination in high transmission settings, MDA must be continued longer and infection levels must be reduced to lower levels than in low-endemic communities. Although our simulations were for Indian settings, qualitatively similar patterns are also expected in other areas. This should be taken into account in decision algorithms to define whether MDA can be interrupted. Transmission assessment surveys should ideally be targeted to communities with the highest pre-control transmission levels, to minimize the risk of programme failure.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1768-y) contains supplementary material, which is available to authorized users.

Efficacy, Safety, and Pharmacokinetics of Coadministered Diethylcarbamazine, Albendazole, and Ivermectin for Treatment of Bancroftian Filariasis

BACKGROUND

Available treatments for lymphatic filariasis (LF) are limited in their longterm clearance of microfilaria from the blood. The safety and efficacy of a single-dose triple-drug therapy of the antifilarial drugs diethylcarbamazine (DEC), ivermectin (IVM), and albendazole (ALB) for LF are unknown.

METHODS

We performed a pilot study to test the efficacy, safety, and pharmacokinetics of single-dose DEC, IVM, and ALB in Wuchereria bancrofti-infected Papua New Guineans. Adults were randomized into 2 treatment arms, DEC 6 mg/kg + ALB 400 mg (N = 12) or DEC 6 mg/kg + ALB 400 mg + IVM 200 μg/kg (N = 12), and monitored for microfilaria, parasite antigenemia, adverse events (AEs), and serum drug levels.

RESULTS

Triple-drug therapy induced >2-log reductions in microfilaria levels at 36 and 168 hours after treatment compared with approximately 1-log reduction with 2 drugs. All 12 individuals who received 3 drugs were microfilaria negative 1 year after treatment, whereas 11 of 12 individuals in the 2-drug regimen were microfilaria positive. In 6 participants followed 2 years after treatment, those who received 3 drugs remained microfilaria negative. AEs, particularly fever, myalgias, pruritus, and proteinuria/hematuria, occurred in 83% vs 50% of those receiving triple-drug compared to 2-drug treatment respectively (P = .021); all resolved within 7 days after treatment. No serious AEs were observed in either group. There was no significant effect of IVM on DEC or ALB drug levels.

CONCLUSIONS

Triple-drug therapy is safe and more effective than DEC + ALB for Bancroftian filariasis and has the potential to accelerate elimination of lymphatic filariasis.

CLINICAL TRIALS REGISTRATION

NCT01975441.

Children and adolescents infected withWuchereria bancroftiin Greater Recife, Brazil: a randomized, year-long clinical trial of single treatments with diethylcarbamazine or diethylcarbamazine–albendazole

In filariasis-endemic areas beyond sub-Saharan Africa, the World Health Organization's recommended strategy for interrupting transmission of the causative parasites is annual, single-dose, mass treatment with a combination of diethylcarbamazine (DEC; given at 6 mg/kg) and albendazole (ALB; given at 400 mg) for 4-6 years (the minimum estimated life-span of the adult parasites). In an open, hospital-based, randomized and controlled trial, with a blinded evaluation of outcome, 82 children and adolescents from Recife, all with Wuchereria bancrofti microfilaraemias, were given either DEC alone (6 mg/kg) or the same dose of DEC combined with ALB (at 400 mg/patient). Every 90 days for 1 year after the single treatment, each patient was checked for microfilaraemia by the filtration of up to 5 ml of venous blood collected at night. One year post-treatment, 16 (39%) of the 41 patients given DEC alone and 20 (49%) of the 41 given DEC-ALB were found microfilaraemic (relative risk=0.8, with a 95% confidence interval of 0.49-1.31) and the corresponding geometric mean levels of microfilaraemia were 2.0% and 1.8% of the levels recorded immediately pre-treatment, respectively (P>0.05). In terms of the prevalences and intensities of microfilaraemia, therefore, the addition of ALB to the DEC appeared to offer no significant benefit.

Modeling the impact and costs of semiannual mass drug administration for accelerated elimination of lymphatic filariasis

The Global Program to Eliminate Lymphatic Filariasis (LF) has a target date of 2020. This program is progressing well in many countries. However, progress has been slow in some countries, and others have not yet started their mass drug administration (MDA) programs. Acceleration is needed. We studied how increasing MDA frequency from once to twice per year would affect program duration and costs by using computer simulation modeling and cost projections. We used the LYMFASIM simulation model to estimate how many annual or semiannual MDA rounds would be required to eliminate LF for Indian and West African scenarios with varied pre-control endemicity and coverage levels. Results were used to estimate total program costs assuming a target population of 100,000 eligibles, a 3% discount rate, and not counting the costs of donated drugs. A sensitivity analysis was done to investigate the robustness of these results with varied assumptions for key parameters. Model predictions suggested that semiannual MDA will require the same number of MDA rounds to achieve LF elimination as annual MDA in most scenarios. Thus semiannual MDA programs should achieve this goal in half of the time required for annual programs. Due to efficiency gains, total program costs for semiannual MDA programs are projected to be lower than those for annual MDA programs in most scenarios. A sensitivity analysis showed that this conclusion is robust. Semiannual MDA is likely to shorten the time and lower the cost required for LF elimination in countries where it can be implemented. This strategy may improve prospects for global elimination of LF by the target year 2020.

The Global Program to Eliminate Lymphatic Filariasis (LF) employs annual mass drug administration (MDA) of antifilarial drugs to reduce infection rates in populations and interrupt transmission. While this program is working well in many countries, progress has been slow in others, and some countries have not yet started MDA programs. We used computer simulation modeling and cost projections to study how increasing MDA frequency from once to twice per year would affect program duration and costs. Our results suggest that semiannual MDA is likely to reduce the time required to eliminate LF by 50% and reduce total program costs (excluding the cost of donated drugs) in most situations. For these and other reasons, we expect semiannual MDA to be superior to annual MDA in most endemic settings. Semiannual MDA should be considered as a means of accelerating LF elimination in areas where it can be implemented, because this may improve prospects for global elimination of LF by the target year 2020.

Macrofilaricidal Activity in Wuchereria bancrofti after 2 Weeks Treatment with a Combination of Rifampicin plus Doxycycline

Infection with the filarial nematode Wuchereria bancrofti can lead to lymphedema, hydrocele, and elephantiasis. Since adult worms cause pathology in lymphatic filariasis (LF), it is imperative to discover macrofilaricidal drugs for the treatment of the infection. Endosymbiotic Wolbachia in filariae have emerged as a new target for antibiotics which can lead to macrofilaricidal effects. In Ghana, a pilot study was carried out with 39 LF-infected men; 12 were treated with 200 mg doxycycline/day for 4 weeks, 16 were treated with a combination of 200 mg doxycycline/day + 10 mg/kg/day rifampicin for 2 weeks, and 11 patients received placebo. Patients were monitored for Wolbachia and microfilaria loads, antigenaemia, and filarial dance sign (FDS). Both 4-week doxycycline and the 2-week combination treatment reduced Wolbachia load significantly. At 18 months posttreatment, four-week doxycycline resulted in 100% adult worm loss, and the 2-week combination treatment resulted in a 50% adult worm loss. In conclusion, this pilot study with a combination of 2-week doxycycline and rifampicin demonstrates moderate macrofilaricidal activity against W. bancrofti.

Lymphadenovarix of the head-neck region--a rare presentation of Bancroftian filariasis

Cystic swellings of the neck in children have limited differential diagnoses, often either lymphatic or vascular malformations. Other cystic inflammations can be the result of tuberculous abscesses, suppurated lymph nodes and actinomycosis. Microfilaria causing lmphadenovarix of head-neck region has not yet been described in the literature. A 10-year-old Indian boy presented with an asymptomatic cystic neck mass of 8 months duration. Aspiration of the swelling demonstrated numerous Wuchereria bancrofti microfilaria and the patient responded well to 6 weeks of daily anti-filarial treatment using diethylcarbamazine citrate (6mg kg(-1) day(-1)). This appears to be the first report of microfilariae-associated lymphadenovarix of head-neck region. Though rare, filariasis should be considered as a differential diagnosis for aberrant swellings where lymphatic filarids are endemic.

Efficacy and safety of drug combinations in the treatment of schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis and onchocerciasis

This review concerns the efficacy and safety of combinations of various drugs, including albendazole (ALB), diethylcarbamazine (DEC), ivermectin (IVM), mebendazole and praziquantel (PZQ). There were no significant pharmacokinetic interactions when ALB-PZQ, ALB-DEC, ALB-IVM or ALB-IVM-PZQ were co-administered. ALB did not add to the cure rate of PZQ in the treatment of Schistosoma japonicum, S. mansoni and S. haematobium. ALB and DEC in combination and alone were ineffective against S. haematobium infections. No combinations (ALB-PZQ, ALB-IVM and ALB-DEC) were superior to ALB against Ascaris lumbricoides and hookworm infections, whilst IVM, but not PZQ or DEC, added to the effect of ALB in the treatment of Trichuris trichiura. Results with ALB added to single-drug therapy with IVM or DEC against lymphatic filariasis were inconclusive, but DEC and IVM in combination appeared to be superior to DEC or IVM alone. None of the drug combinations against lymphatic filariasis showed more adverse reactions than single-drug therapy. In onchocerciasis patients, ALB and IVM were safe in those also infected with lymphatic filariasis, but were not superior to IVM alone. Existing policies are based on limited knowledge. Well conducted, comparative, randomised controlled studies would greatly aid in the future use of these drug combinations.

Non-disjunction events induced by albendazole in human cells

Albendazole (ABZ), a benzimidazole carbamate used for the treatment of several human helminthiases has high affinity for tubulin, which results in an inhibition of microtubule polymerization, blocking several vital processes in the parasites, such as motility and nutrient uptake. The ability of ABZ to act as mitotic spindle poison leads to a potential risk for aneuploidy induction in exposed human beings. ABZ, as well as albendazole sulphoxide (ABZSO), its main metabolite, induce micronuclei in human cells in a dose-dependent manner. Despite recognition that ABZ and ABZSO increase micronucleus frequency, their potential as inducers of non-disjunction in human cells, an event considered more frequent than chromosome loss, and one of the main mechanisms involved in aneuploidy induction, has not been evaluated. In the present work, we investigated the ability of ABZ and ABZSO to induce non-disjunction in cultured human lymphocytes. Non-disjunction was scored by chromosome-specific FISH using a classical or alpha satellite probe for chromosomes 1 and 7, respectively. Significant increase in non-disjunction events that involved either chromosome were observed in cells treated with ABZ or ABZSO. Both ABZ and ABZSO induced non-disjunction at lower concentrations than those at which MN were observed.

Efficacy of co-administered diethylcarbamazine and albendazole against adult Wuchereria bancrofti

Although diethylcarbamazine (DEC) and albendazole are recommended to interrupt transmission of Wuchereria bancrofti, little is known about the macrofilaricidal effect of this drug combination. Forty-seven men with W. bancrofti infection were randomly assigned to receive a single dose of either DEC alone (6 mg/kg) (n=25) or a combination of DEC (6 mg/kg) and albendazole (400 mg) (n=22). Physical examinations for scrotal nodules (resulting from worm death) and ultrasound examinations (to detect living adult worms) were performed before treatment and 7, 14, 30, 45, 60, 90, 180, 270 and 360 days after treatment. Blood was examined for microfilariae before and 30 days and 360 days after treatment. Seven days post treatment, intrascrotal nodules were detected at the site of 21 (46.7%) adult worm nests in men who received DEC alone compared with 2 (6.1%) sites in men who received DEC and albendazole (P=0.002). One year after treatment, 10 (22.2%) original adult worm nests remained detectable by ultrasound among men who received DEC alone compared with 18/32 (56.3%) nests among men who received both drugs (P=0.016). Microfilaraemia prevalence and density decreased to a similar extent in both groups. Addition of albendazole appeared to decrease the macrofilaricidal effect of DEC against W. bancrofti, with no detectable enhancement in microfilarial suppression.

Adverse reactions following mass drug administration during the Programme to Eliminate Lymphatic Filariasis in Orissa State, India

The frequency and severity of adverse reactions are the main reasons for low compliance of mass drug administration (MDA) under the Programme to Eliminate Lymphatic Filariasis (PELF). This paper reports the frequency and types of adverse reactions during two MDAs during January 2002 and September 2004 in the State of Orissa, India. Of the people who consumed the drugs, 15.5% in the 2002 MDA and 16.5% in the 2004 MDA reported one or more adverse reactions. This rate is higher (49.7%) in a group of individuals who were monitored for 6 days from the day of consumption of drugs during the 2002 MDA. However, many of these reactions were mild. No significant difference was found in the frequency of adverse reactions between MDA with diethylcarbamazine (DEC) alone and with DEC and albendazole. Significant gender differences were found in the 2004 MDA but no such differences were found in the 2002 MDA; however, the frequency of adverse reactions increased with age. Of all the adverse reactions, systemic adverse reactions typically associated with microfilarial death were more frequent. The frequency of adverse reactions was higher in microfilaraemics compared with amicrofilaraemic controls. The present study warrants developing an active adverse reaction surveillance system to minimise the impact of adverse reactions on MDA compliance.

Albendazole for lymphatic filariasis

BACKGROUND

Mass treatment with albendazole co-administered with another antifilarial drug is part of a global programme to eliminate lymphatic filariasis. We sought reliable evidence of the effects of albendazole on the disease and the parasite.

OBJECTIVES

To summarize the effects of albendazole alone or in combination with antifilarial drugs for clinical treatment and community control of lymphatic filariasis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (August 2005), CENTRAL (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to August 2005), EMBASE (1974 to August 2005), LILACS (1982 to August 2005), and reference lists. We also contacted researchers, the World Health Organization, and GlaxoSmithKline.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of albendazole alone or combined with another antifilarial drug for treating individuals with lymphatic filariasis, or for reducing transmission in endemic communities.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility and trial quality, and extracted data. Authors contacted investigators for missing information or clarification.

MAIN RESULTS

Seven trials including 6997 participants (995 with detectable microfilariae) met the criteria. A comparison of albendazole and placebo detected no effect on microfilariae prevalence (920 participants; 3 trials); one trial (499 participants) reported significantly lower microfilariae density at six months. Albendazole performed slightly worse than ivermectin in two trials (436 participants). Compared with diethylcarbamazine (DEC), two small trials (56 participants) found little difference in microfilariae prevalence over an extended follow up. One larger trial (502 participants) found a statistically significant effect for DEC at six months, but none at three months. Microfilariae prevalence and density were statistically significantly lower with the combination of albendazole and ivermectin compared with ivermectin alone in two of three trials (649 participants). Two trials compared albendazole plus DEC with DEC alone and found no statistically significant difference in microfilariae prevalence, though one trial favoured the combination at six months (relative risk 0.62, 95% confidence interval 0.32 to 1.21; 491 participants). This trial also found a statistically significant reduction in microfilariae density.

AUTHORS' CONCLUSIONS

There is insufficient evidence to confirm or refute that albendazole co-administered with DEC or ivermectin is more effective than DEC or ivermectin alone in clearing microfilariae or killing adult worms. Albendazole combined with ivermectin appears to have a small effect on microfilaraemia, but this was not consistently demonstrated. The effect of albendazole against adult and larval filarial parasites, alone and in combination with other antifilarial drugs, deserves further rigorous research.

Albendazole for the control and elimination of lymphatic filariasis: systematic review

OBJECTIVES

The Global Programme to Eliminate Lymphatic Filariasis recommends albendazole in combination with other antifilarial drugs. This systematic review examines albendazole in treatment and control of lymphatic filariasis. DATASOURCES: The Cochrane Controlled Trials Register, MEDLINE and EMBASE to April 2005; contacting experts, international organisations and drug manufacturers.

METHODS

Randomised or quasi-randomised controlled trials included; two reviewers independently assessed eligibility, quality, and extracted data. We calculated the relative risk of microfilaraemia (mf) prevalence using fixed effect, or random effects model in case of heterogeneity.

RESULTS

Six trials met inclusion criteria. Three trials compared albendazole with placebo: no effect was demonstrated on mf prevalence, but density was lower in one of the three studies at 6 months. Three trials added albendazole to ivermectin, with no demonstrable effect; prevalence tended to be lower at 4--6 months but not at 12 months (4--6 months; RR 0.49, 95% CI 0.18 to 1.39, n=255, 2 trials; 12 months: RR 1.00, 95% CI 0.88 to 1.13, n=348, 2 trials). Mf density was significantly lower in two of the three trials; one of two trials measuring density at 12 months showed a difference. Three trials added albendazole to diethylcarbamazine; two were small trials with no difference demonstrated; the third study tended to favour combination at 6 months (RR=0.62, 95% CI 0.32 to 1.21, n=491), with a significant difference for density.

CONCLUSIONS

The effect of albendazole against adult and larval filarial parasites, alone and in combination with other antifilarial drugs, deserves further rigorous research.