A randomized double-blind placebo-controlled field trial of ivermectin andalbendazole alone and in combination for the treatment of lymphatic filariasis in Ghana

The efficacy and safety of single-dose ivermectin (150-200 mu g/kg) and alb endazole (400 mg) treatment administered separately or in combination for W uchereria bancrofti infections were assessed in 1996-98 in a randomized dou ble-blind placebo-controlled field trial in Ghana: 1425 individuals from 4 lymphatic filariasis-endemic villages, 340 of whom were microfilaria (mf)-p ositive before treatment, were randomized into 4 groups to receive albendaz ole alone, ivermectin alone, combination of albendazole and ivermectin, or placebo, respectively. Individuals were followed for 5 days after treatment to record any adverse reactions, and the effect of treatment on microfilar aemia was monitored in night-blood samples after 3, 6 and 12 months. Treatm ent efficacy was analysed for 236 mf-positive individuals who had greater t han or equal to 100 mf/mL of blood and who were also present for examinatio n at 12 months after treatment. Compared to the placebo group, the ivermect in and combination groups both showed statistically significant reductions in geometric mean mf intensities at the follow-up examinations (to 6.7% and 0.9%, 9.9% and 6.9%, and 21.7% and 11.4% of pre-treatment levels, respecti vely, at 3, 6 and 12 months after treatment). Compared to the ivermectin gr oup, however, the reduction in the combination group was significantly grea ter only at 3 months after treatment, but not after 6 or 12 months. The alb endazole group showed a slow but non-significant reduction over the same pe riod. Adverse reactions were few and mostly mild (no severe reactions were recorded), and no significant differences were observed between the treatme nt groups. Both ivermectin and combination treatment thus appeared effectiv e and safe for treatment of lymphatic filariasis, but the difference in eff icacy was minor and the study did not provide clear evidence for the combin ation drug therapy, as compared to ivermectin therapy alone, to be superior for control of lymphatic filariasis.