Human loiasis in a Cameroonian village: a double-blind, placebo-controlled, crossover clinical trial of a three-day albendazole regimen.

Because of the life-threatening, post-treatment reactions that have occurred in patients with loiasis treated with ivermectin, evaluation of a short-course albendazole regimen was undertaken in a Loa-endemic region of Cameroon. In a placebo-controlled, double-blinded, crossover study, 99 subjects with microfilaremia (100-3,3837/mL) were assigned to receive albendazole (400 mg; n = 48) or placebo (n = 51) for three days and were followed for 180 days; at day 180, the groups were crossed over and followed for an additional six months. In those initially receiving albendazole (ALB/PLAC), microfilarial levels decreased significantly by day 90 (P < 0.043), but returned to baseline by day 180. In those receiving albendazole at day 180 (PLAC/ALB), microfilarial levels also decreased following albendazole (P = 0.005). Blood eosinophil and antifilarial IgG levels did not change significantly for either group, although antifilarial IgG4 levels did in the ALB/PLAC group at day 180. Most subjects continued to have elevations in microfilaremia, suggesting that more intensive regimens of albendazole will be necessary to reduce Loa microfilaremia to levels safe enough to allow for ivermectin use.