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Funder: Unitaid, Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe coronavirus disease 2019 (COVID-19), but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is a US Food and Drug Administration (FDA) approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modeling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase I trial in healthy adult participants was undertaken with high-dose nitazoxanide. Participants received 1,500 mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose, and schedule. Intensive pharmacokinetic (PK) sampling was undertaken day 1 and 5 with minimum concentration (Cmin ) sampling on days 3 and 7. Fourteen healthy participants were enrolled between February 18 and May 11, 2021. All 14 doses were completed by 10 of 14 participants. Nitazoxanide was safe and with no significant adverse events. Moderate gastrointestinal disturbance (loose stools or diarrhea) occurred in 8 participants (57.1%), with urine and sclera discoloration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on the first dose and maintained throughout. Nitazoxanide administered at 1,500 mg b.i.d. with food was safe with acceptable tolerability a phase Ib/IIa study is now being initiated in patients with COVID-19.

Introduction: Sub-dermal hormone implants, such as levonorgestrel (LNG), are a safe and desirable form of long-acting contraception, but their use among HIV-positive women on antiretroviral therapy (ART) may be compromised given the potential for a cytochrome P450 3A-mediated drug–drug interaction. Our study aimed to characterize the pharmacokinetics of LNG released from a sub-dermal implant over six months in HIV-positive Ugandan women on nevirapine (NVP)- or efavirenz (EFV)-based ART. Material and Methods: This non-randomized, parallel group study compared LNG pharmacokinetics between HIV-positive Ugandan women not yet eligible for ART (control group, n=18) and those on stable NVP- (n=20) or EFV- (n=20) based ART. The two-rod (75 mg/rod) LNG sub-dermal implant was inserted at study enrolment. LNG sampling was obtained pre-implant and at weeks 1, 4, 12 and 24 post-insertion. LNG concentrations were analyzed using a validated LC-MS/MS method, with an assay calibration range of 50–1500 pg/mL. Safety monitoring, including a pregnancy test, was conducted at each study visit. Results: At enrolment, participants had a mean age of 31 years; CD4+ cell counts were similar between the control, NVP and EFV groups (758, 645 and 568 cells/mm3, respectively; p=0.09); all women in the NVP and EFV groups had an undetectable HIV-RNA. Women in the control group had a higher baseline body weight (73 kg) compared to those in the NVP (63 kg; p=0.03) or EFV groups (60 kg; p