A randomized, open-label two-period crossover pilot study to evaluate the relative bioavailability in the fed state of atovaquone-proguanil (Atoguanil™) versus atovaquone-proguanil hydrochloride (Malarone®) in healthy adult participants

Atoguanil™ is a novel complex of atovaquone (ATV) and proguanil (PG) with enhanced ATV bioavailability compared to Malarone®. This pilot study assessed whether the relative bioavailability (F rel ) of ATV, PG, and the primary PG metabolite cycloguanil (CG) following a single oral dose in the fed state of Atoguanil was similar to Malarone despite a 50% lower ATV dose. This open-label, single-dose, randomized 2-period, 2-treatment, balanced crossover study was conducted between 17th November 2021 and 18th March 2022. Eligible participants (aged 18–55 years) were randomized (1:1) in period 1 to Atoguanil (ATV/PG 500/348 mg) or Malarone (ATV/PG hydrochloride 1000/400 mg) administered following a high-fat, high caloric meal. After a 24-day washout period, participants crossed treatment arms. For the doses tested, F rel was assumed similar if 90%CIs were between 80 and 125% for the geometric mean ratio of the least square mean differences for each exposure parameter. In 15 evaluable participants, F rel was similar for ATV C max (93.6% [90%CI 83.6, 104.9]) but not AUC 0-inf (77.8% [67.4, 89.8]), for PG AUC 0-inf (95.6% [92.1, 99.2]) but not C max (82.4% [75.8, 89.5]), and for both CG C max (100.8% [95.0, 107.0]) and AUC 0-inf (102.9% [98.4, 107.7]). Nine adverse events occurred; all were of mild severity and not considered treatment related. At the doses tested, ATV F rel was lower following Atoguanil versus Malarone based on AUC 0-inf , though when adjusted for dose F rel increased by 156%. Both drugs were well tolerated with no safety concerns. ClinicalTrials.gov: NCT04866602 (April 26th, 2021)