Randomized, placebo controlled phase I trial of safety, pharmacokinetics, pharmacodynamics and acceptability of tenofovir and tenofovir plus levonorgestrel vaginal rings in women

Abstract

To prevent the global health burdens of human immunodeficiency virus [HIV] and unintended/mistimed pregnancies, we developed an intravaginal ring [IVR] that delivers tenofovir [TFV] at ~10mg/day alone or with levonorgestrel [LNG] at ~20μg/day for 90 days. We present safety, pharmacokinetics, pharmacodynamics, acceptability and drug release data in healthy women. CONRAD A13-128 was a randomized, placebo controlled phase I study. We screened 86 women; 51 were randomized to TFV, TFV/LNG or placebo IVR [2:2:1] and 50 completed all visits, using the IVR for approximately 15 days. We assessed safety by adverse events, colposcopy, vaginal microbiota, epithelial integrity, mucosal histology and immune cell numbers and phenotype, cervicovaginal [CV] cytokines and antimicrobial proteins and changes in systemic laboratory measurements, and LNG and TFV pharmacokinetics in multiple compartments. TFV pharmacodynamic activity was measured by evaluating CV fluid [CVF] and tissue for antiviral activity using in vitro models. LNG pharmacodynamic assessments were timed based on peak urinary luteinizing hormone levels. All IVRs were safe with no significant colposcopic, mucosal, immune and microbiota changes and were acceptable. Among TFV containing IVR users, median and mean CV aspirate TFV concentrations remained above 100,000 ng/mL 4 hours post IVR insertion and mean TFV-diphosphate [DP] concentrations in vaginal tissue remained above 1,000 fmol/mg even 3 days post IVR removal. CVF of women using TFV-containing IVRs completely inhibited [94-100%] HIV infection in vitro. TFV/LNG IVR users had mean serum LNG concentrations exceeding 300 pg/mL within 1 hour, remaining high throughout IVR use. All LNG IVR users had a cervical mucus Insler score <10 and the majority [95%] were anovulatory or had abnormal cervical mucus sperm penetration. Estimated in vivo TFV and LNG release rates were within expected ranges. All IVRs were safe with the active ones delivering sustained high concentrations of TFV locally. LNG caused changes in cervical mucus, sperm penetration, and ovulation compatible with contraceptive efficacy. The TFV and TFV/LNG rings are ready for expanded 90 day clinical testing. Trial registration ClinicalTrials.gov #NCT02235662.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. CONSORT figure CONRAD A13-128 study population.

Fig 2

(A) TFV in CV aspirate. Blue Bars: TFV IVR, Red Bars: TFV/LNG IVR, Visit 4, pooled across sampling times of 1, 2, 4 and 8 hours post insertion [n = 18 for each IVR group], Visit 5: 24 hours post insertion [n = 20 for TFV and n = 19 for TFVLNG IVRs], Visit 6: LH surge or Menstrual Cycle day 17 [n = 20 for each IVR group], Visit 7: Prior to IVR Removal [n = 19 for each IVR group], Visit 8: 24 hours post removal [n = 15 for TFV and n = 20 for TFVLNG IVRs]. Reference line indicates 1,000 ng/mL, aspirate level associated with 75% reduction in HIV acquisition in CAPRISA 004 study subset [41, 42] (B) TFV [ng/mg] in vaginal tissue. Blue Bars: TFV IVR, Red Bars: TFV/LNG IVR, Proximal indicates biopsy was obtained close to the IVR, in the posterior vaginal fornix, Distal indicates biopsy was obtained farther from the IVR, in the lower 1/3 of the vagina closer to the introitus. Visit 5: 24 hours post insertion [for proximal biopsies n = 15 for TFV and n = 16 for TFVLNG IVR. For distal biopsies, n = 19 for TFV and n = 20 for TFVLNG IVR]. Visit 7: Prior to IVR Removal [for proximal biopsies n = 15 for TFV and n = 17 for TFVLNG IVR] and [for distal biopsies, n = 19 for TFV and n = 20 for TFVLNG IVR]. Visit 8: 24 hours post removal [n = 9 for TFV and n = 8 for TFVLNG IVR], Visit 9 72 hours post removal [n = 5 for TFV and n = 9 for TFVLNG IVR]. Dashed line indicates TFV level [10 ng/mg] associated with high TFV-DP concentrations of approximately 1,000 fmol/mg [24, 41, 42]. (C) TFV-DP [fmol/mg] in vaginal tissue. Blue Bars: TFV IVR, Red Bars: TFV/LNG IVR. Proximal indicates biopsy was obtained close to the IVR, in the posterior vaginal fornix. Distal indicates biopsy was obtained farther from the IVR, in the lower 1/3 of the vagina closer to the introitus. Visit 5: 24 hours post insertion [for proximal biopsies, n = 14 for TFV and n = 16 for TFVLNG IVR. For distal biopsies, [n = 19 for TFV and n = 20 for TFVLNG IVR], Visit 7: Prior to IVR Removal [for proximal biopsies, n = 14 for TFV and n = 17 for TFVLNG IVR]. For distal biopsies, n = 19 for both IVRs], Visit 8: 24 hours post removal [n = 8 for TFV and n = 7 for TFVLNG IVR], Visit 9 72 hours post removal [n = 5 for TFV and n = 9 for TFVLNG IVR]. Dashed line indicates levels found to be protective against SHIV transmission in non-human primates [43, 44] (D) TFV in CV fluid [ng/mg] obtained from lower genital tract swabs. Blue Bars: TFV IVR, Red Bars: TFV/LNG IVR, Visit 4: 1–8 hours post IVR insertion vaginal swab taken near IVR [n = 20 combined observations for TFV IVR and TFVLNG IVR], Visit 5: 24 hours post insertion taken near IVR [n = 20 for both IVRs], ectocervix [n = 20 for both IVRs] and introitus [n = 20 for both IVRs], Visit 7: Prior to IVR removal, taken near IVR [n = 20 for both IVRs], ectocervix [n = 20 for both IVRs] and introitus [n = 20 for TFV and n = 18 for TFV/LNG IVR], Visit 8: 24 hours post removal [n = 19 for TFV and n = 20 for TFVLNG IVR]. Cx = Ectocervix, Int = Introitus, IVR = vaginal near IVR.

Fig 3

(A) HIV inhibition by cervico-vaginal fluids in vitro among placebo IVR users at baseline [visit 4] versus end of treatment [visit 7]. (B) HIV inhibition by cervico-vaginal fluids in vitro among TFV and TFV/LNG IVR users at baseline [visit 4] versus end of treatment [visit 7].

Fig 4. Plasma LNG [pg/mL] in TFV/LNG IVR users [n = 20].

1 Hr = 1 hour post IVR insertion. 2 HRS = 2 hours post IVR insertion. 4 HRS = 4 hours post IVR insertion. 8 HRS = 8 hours post IVR insertion. 24 HRS = 24 hours post IVR insertion. V6 = Visit 6 [performed at the urinary LH surge or menstrual cycle day 17, whichever came first]. END TX = End of Treatment, at V7, 8–10 days after V6. 24 HRS POST REM = 24 hours after IVR removal. Dashed line indicates concentration above which data support contraceptive efficacy of systemic LNG methods [reviewed in [46]].