RCT: Albendazole–Ivermectin Co-Formulation Achieves Higher Cure Rates for T. trichiura and Hookworms
22 Jan, 2025 | 12:41h | UTCBackground: Soil-transmitted helminthiases (STH) affect an estimated 1.5 billion people worldwide, with Trichuris trichiura and hookworms remaining particularly challenging to treat. Although single-dose albendazole or mebendazole is standard in mass deworming programs, these agents show limited efficacy against T. trichiura and often leave Strongyloides stercoralis under-treated. Ivermectin has demonstrated broad activity against multiple parasites, suggesting that a combined albendazole–ivermectin regimen might enhance treatment outcomes, simplify protocols, and potentially curb emerging drug resistance.
Objective: This trial aimed to evaluate the safety, efficacy, and acceptability of a novel fixed-dose co-formulation (FDC) tablet containing albendazole (400 mg) plus a higher-than-standard, fixed dose of ivermectin (9 mg or 18 mg), administered once daily (FDC×1) or for three consecutive days (FDC×3). Investigators compared these regimens against single-dose albendazole alone for the treatment of T. trichiura, hookworms, and S. stercoralis in children and adolescents.
Methods: In this adaptive, randomized, parallel-group, phase 2/3 trial, 1001 participants aged 5–18 years were recruited from schools in Ethiopia, Kenya, and Mozambique. All were infected with at least one of T. trichiura, hookworms, or S. stercoralis. Eligible participants were allocated (by computer-generated block randomization) to either a single dose of albendazole 400 mg (control), a single-dose FDC of albendazole–ivermectin (FDC×1), or a three-day FDC regimen (FDC×3). Primary endpoints included safety (phase 2) and efficacy (phase 3), determined by cure rates at day 21 using the Kato–Katz and Baermann methods. Laboratory staff were blinded to treatment assignment.
Results: No serious adverse events were reported; mild-to-moderate gastrointestinal symptoms were the most frequent treatment-related events, resolving spontaneously within 48 hours. Cure rates for T. trichiura were 35.9% (95% CI 27.7–44.1) in the albendazole group, 82.9% (78.2–87.5) in FDC×1, and 97.2% (95.2–99.3) in FDC×3. For hookworms, cure rates were 65.1% (56.0–74.2) with albendazole, 79.8% (72.8–86.9) with FDC×1, and 95.0% (91.1–98.9) with FDC×3. Egg reduction rates in FDC arms consistently surpassed those of albendazole alone, especially for multi-day dosing. The sample size for S. stercoralis was insufficient to power a definitive efficacy conclusion, though ivermectin-containing arms trended toward favorable results. Palatability questionnaires indicated the orodispersible FDC was well accepted in taste, texture, and overall ease of administration.
Conclusions: A new co-formulation of albendazole plus ivermectin delivered at higher, fixed doses demonstrated an excellent safety profile and superior efficacy against T. trichiura and hookworms compared with albendazole monotherapy. This approach may streamline programmatic control of multiple STH species, including S. stercoralis, while contributing to reduced transmission in endemic communities.
Implications for Practice: For mass deworming initiatives, a single-dose FDC offers improved cure rates over albendazole alone while preserving simplicity. Where higher efficacy is critical—such as programs targeting near-elimination goals or in clinical settings—the three-day regimen may be preferable. Nonetheless, implementation feasibility, cost considerations, and further confirmation of efficacy against S. stercoralis and other co-endemic parasites remain important next steps.
Study Strengths and Limitations: Strengths include a multicenter design across three countries and a rigorous adaptive protocol that assessed both safety and efficacy. Limitations include the lack of blinding for participants and care providers (though outcome assessors were blinded), the underpowered sample size for S. stercoralis, and reliance on single-stool diagnostics, which may underestimate residual infections.
Future Research: Additional large-scale studies should confirm these findings in varied geographic regions and evaluate the cost-effectiveness of both single-dose and multi-day FDC strategies. Integrating albendazole–ivermectin with treatment programs for other neglected tropical diseases (e.g., onchocerciasis) could further amplify public health benefits. Genomic and pharmacokinetic analyses will clarify resistance patterns and optimize dosing regimens for broader implementation.
Reference: Krolewiecki A, Kepha S, Fleitas PE, van Lieshout L, Gelaye W, Messa A Jr, et al. “Albendazole–ivermectin co-formulation for the treatment of Trichuris trichiura and other soil-transmitted helminths: a randomised phase 2/3 trial.” The Lancet Infectious Diseases. Published January 10, 2025. DOI: https://doi.org/10.1016/S1473-3099(24)00669-8