Benznidazole, currently the standard treatment and the best option for people with Chagas disease, is effective but has limitations: the treatment lasts 60 days, and some 20% of patients stop treatment due to side effects, which can include skin rashes, gastric intolerance, and neuromuscular problems. To improve adherence to treatment, DNDi and partners decided to test the efficacy of new regimens where exposure to benznidazole would be reduced, either due to shorter treatment, lower doses, or both.

In 2013, a proof-of-concept trial showed that fosravuconazole, an azole-class antifungal drug discovered by Eisai Ltd (Japan), had good safety and was effective at clearing the parasite, but efficacy was not sustained. A Phase I drug-drug interaction study assessed the safety and pharmacokinetic interactions of fosravuconazole and benznidazole administered separately and in combination. No major clinically relevant safety or tolerability issues were identified.

The BENDITA (Benznidazole New Doses Improved Treatment & Therapeutic Associations) study looked for regimens at least as effective as the standard treatment, with fewer side effects. From 2016 to 2018, a Phase II, randomized, placebo-controlled study was carried out in three sites in Bolivia to test six benznidazole treatments of differing lengths and dosages, both as a monotherapy and in combination with fosravuconazole, against a placebo. The aim was to improve efficacy, safety, and tolerability of treatment of adults with chronic indeterminate Chagas disease, thereby improving patients’ adherence and making the treatment more acceptable to physicians.

Results showed that the new regimens’ main benefits were related to an improved safety profile, as well as a better adherence, but further assessment was required to confirm non-inferiority compared to standard regimens. DNDi continues to work with national programmes, partners, and health ministries of endemic countries to confirm these results and encourage the necessary steps to register the new regimen. In 2023, DNDi started a Phase III clinical trial in Argentina to validate a two-week and four-week regimen with benznidazole for adults in the chronic phase of the disease.

Project updates

The NuestroBen study continued recruitment at six sites in Argentina (four in Buenos Aires and two in the north of the country), and recruitment of a total of 300 participants is expected by the end of 2025. At least one study site in Bolivia is expected to open in the first quarter of 2025.

The reanalysis of the BENDITA study based on individual patient data was completed, and the results and findings on healthcare provider acceptability of the shorter regimens will be published in early 2025.