Voluntariness of consent in paediatric HIV clinical trials: a mixed-methods, cross-sectional study of participants in the CHAPAS-4 and ODYSSEY trials in Uganda.

OBJECTIVES: To examine the voluntariness of consent in paediatric HIV clinical trials and the associated factors. DESIGN: Mixed-methods, cross-sectional study combining a quantitative survey conducted concurrently with indepth interviews. SETTING AND PARTICIPANTS: From January 2021 to April 2021, we interviewed parents of children on first-line or second-line Anti-retroviral therapy (ART) in two ongoing paediatric HIV clinical trials [CHAPAS-4 (ISRCTN22964075) and ODYSSEY (ISRCTN91737921)] at the Joint Clinical Research Centre Mbarara, Uganda. OUTCOME MEASURES: The outcome measures were the proportion of parents with voluntary consent, factors affecting voluntariness and the sources of external influence. Parents rated the voluntariness of their consent on a voluntariness ladder. Indepth interviews described participants' lived experiences and were aimed at adding context. RESULTS: All 151 parents randomly sampled for the survey participated (84% female, median age 40 years). Most (67%) gave a fully voluntary decision, with a score of 10 on the voluntariness ladder, whereas 8% scored 9, 9% scored 8, 6% scored 7, 8% scored 6 and 2.7% scored 4. Trust in medical researchers (adjusted OR 9.90, 95% CI 1.01 to 97.20, p=0.049) and male sex of the parent (adjusted OR 3.66, 95% CI 1.00 to 13.38, p=0.05) were positively associated with voluntariness of consent. Prior research experience (adjusted OR 0.31, 95% CI 0.12 to 0.78, p=0.014) and consulting (adjusted OR 0.25. 95% CI 0.10 to 0.60, p=0.002) were negatively associated with voluntariness. Consultation and advice came from referring health workers (36%), spouses (29%), other family members (27%), friends (15%) and researchers (7%). The indepth interviews (n=14) identified the health condition of the child, advice from referring health workers and the opportunity to access better care as factors affecting the voluntariness of consent. CONCLUSIONS: This study demonstrated a high voluntariness of consent, which was enhanced among male parents and by parents' trust in medical researchers. Prior research experience of the child and advice from health workers and spouses were negatively associated with the voluntariness of parents' consent. Female parents and parents of children with prior research experience may benefit from additional interventions to support voluntary participation.

Pharmacokinetic Data of Dolutegravir in Second-line Treatment of Children With Human Immunodeficiency Virus: Results From the CHAPAS4 Trial.

BACKGROUND: Dolutegravir (DTG), combined with a backbone of 2 nucleoside reverse transcriptase inhibitors, is currently the preferred first-line treatment for human immunodeficiency virus (HIV) in childhood. CHAPAS4 is an ongoing randomized controlled trial investigating second-line treatment options for children with HIV. We did a nested pharmacokinetic (PK) substudy within CHAPAS4 to evaluate the DTG exposure in children with HIV taking DTG with food as part of their second-line treatment. METHODS: Additional consent was required for children on DTG enrolled in the CHAPAS4 trial to participate in this PK substudy. Children weighing 14-19.9 kg took 25 mg DTG as dispersible tablets and children ≥20 kg took 50 mg film-coated tablets. Steady-state 24-hour DTG plasma concentration-time PK profiling was done at t = 0 and 1, 2, 4, 6, 8, 12, and 24 hours after observed DTG intake with food. Reference adult PK data and pediatric data from the ODYSSEY trial were used primarily for comparison. The individual target trough concentration (Ctrough) was defined as 0.32 mg/L. RESULTS: Thirty-nine children on DTG were included in this PK substudy. The geometric mean (GM) area under the concentration-time curve over the dosing interval (AUC0-24h) was 57.1 hours × mg/L (coefficient of variation [CV%], 38.4%), which was approximately 8% below the average AUC0-24h in children in the ODYSSEY trial with comparable dosages, but above the adult reference. The GM (CV%) Ctrough was 0.82 mg/L (63.8%), which was comparable to ODYSSEY and adult reference values. CONCLUSIONS: This nested PK substudy shows that the exposure of DTG taken with food in children on second-line treatment is comparable with that of children in the ODYSSEY trial and adult references. Clinical Trials Registration.ISRCTN22964075.

First Pharmacokinetic Data of Tenofovir Alafenamide Fumarate and Tenofovir With Dolutegravir or Boosted Protease Inhibitors in African Children: A Substudy of the CHAPAS-4 Trial.

BACKGROUND: We evaluated the pharmacokinetics of tenofovir alafenamide fumarate (TAF) and tenofovir in a subset of African children enrolled in the CHAPAS-4 trial. METHODS: Children aged 3-15 years with human immunodeficiency virus infection failing first-line antiretroviral therapy were randomized to emtricitabine/TAF versus standard-of-care nucleoside reverse transcriptase inhibitor combination, plus dolutegravir, atazanavir/ritonavir, darunavir/ritonavir, or lopinavir/ritonavir. Daily emtricitabine/TAF was dosed according to World Health Organization (WHO)-recommended weight bands: 120/15 mg in children weighing 14 to <25 kg and 200/25 mg in those weighing ≥25 kg. At steady state, 8-9 blood samples were taken to construct pharmacokinetic curves. Geometric mean (GM) area under the concentration-time curve (AUC) and the maximum concentration (Cmax) were calculated for TAF and tenofovir and compared to reference exposures in adults. RESULTS: Pharmacokinetic results from 104 children taking TAF were analyzed. GM (coefficient of variation [CV%]) TAF AUClast when combined with dolutegravir (n = 18), darunavir/ritonavir (n = 34), or lopinavir/ritonavir (n = 20) were 284.5 (79), 232.0 (61), and 210.2 (98) ng*hour/mL, respectively, and were comparable to adult reference values. When combined with atazanavir/ritonavir (n = 32), TAF AUClast increased to 511.4 (68) ng*hour/mL. For each combination, tenofovir GM (CV%) AUCtau and Cmax remained below reference values in adults taking 25 mg TAF with a boosted protease inhibitors. CONCLUSIONS: In children, TAF combined with boosted PIs or dolutegravir and dosed according to WHO-recommended weight bands provides TAF and tenofovir concentrations previously demonstrated to be well tolerated and effective in adults. These data provide the first evidence for use of these combinations in African children. CLINICAL TRIALS REGISTRATION: ISRCTN22964075.

Dolutegravir dosing for children with HIV weighing less than 20 kg: pharmacokinetic and safety substudies nested in the open-label, multicentre, randomised, non-inferiority ODYSSEY trial.

BACKGROUND: Dolutegravir-based antiretroviral therapy is a preferred first-line treatment for adults and children living with HIV; however, very little pharmacokinetic data for dolutegravir use are available in young children. We therefore aimed to evaluate dolutegravir dosing and safety in children weighing 3 kg to less than 20 kg by assessing pharmacokinetic parameters and safety data in children taking dolutegravir within the ODYSSEY trial. METHODS: We did pharmacokinetic substudies nested within the open-label, multicentre, randomised, non-inferiority ODYSSEY trial. We enrolled children from seven research centres in South Africa, Uganda, and Zimbabwe. Children weighing 3 kg to less than 14 kg received 5 mg dispersible tablets of dolutegravir according to WHO weight bands: 5 mg for children weighing 3 kg to less than 6 kg and younger than 6 months, 10 mg for children weighing 3 kg to less than 6 kg and aged 6 months or older, 15 mg for children weighing 6 kg to less than 10 kg, and 20 mg for children weighing 10 kg to less than 14 kg. Children weighing 14 kg to less than 20 kg received a 25 mg film-coated tablet once per day early in the trial or 25 mg dispersible tablets (five 5 mg tablets once per day) later in the trial. A minimum of eight children per weight band or dose was targeted for 24 h pharmacokinetic profiling at steady state. The primary pharmacokinetic parameter was the trough concentration 24 h after observed dolutegravir intake (Ctrough). Pharmacokinetic targets were based on adult dolutegravir Ctrough and the 90% effective concentration (EC90; ie, 0·32 mg/L). Safety was evaluated in eligible children consenting to pharmacokinetic substudies. FINDINGS: Between May 25, 2017, and Aug 15, 2019, we enrolled 72 children aged between 3 months and 11 years. 71 children were included in the safety population and 55 (76%) of 72 children contributed 65 evaluable pharmacokinetic profiles. Geometric mean Ctrough in children on dispersible tablets in weight bands between 3 kg and less than 20 kg ranged between 0·53-0·87 mg/L, comparable to the adult geometric mean Ctrough of 0·83 mg/L. Variability was high with coefficient of variation percentages ranging between 50% and 150% compared with 26% in adults. Ctrough below EC90 was observed in four (31%) of 13 children weighing 6 kg to less than 10 kg taking 15 mg dispersible tablets, and four (21%) of 19 weighing 14 kg to less than 20 kg taking 25 mg film-coated tablets. The lowest geometric mean Ctrough of 0·44 mg/L was observed in children weighing 14 kg to less than 20 kg on 25 mg film-coated tablets. Exposures were 1·7-2·0 times higher on 25 mg dispersible tablets versus 25 mg film-coated tablets. 19 (27%) of 71 children had 29 reportable grade 3 or higher adverse events (13 serious adverse events, including two deaths), none of which were related to dolutegravir. INTERPRETATION: Weight-band dosing of paediatric dolutegravir dispersible tablets provides appropriate drug exposure in most children weighing 3 kg to less than 20 kg, with no safety signal. 25 mg film-coated tablets did not achieve pharmacokinetic parameters in children weighing 14 kg to less than 20 kg, which were comparable to adults, suggesting dosing with dispersible tablets is preferable or a higher film-coated tablet dose is required. FUNDING: Paediatric European Network for Treatment of AIDS Foundation, ViiV Healthcare, and UK Medical Research Council.

Dolutegravir as First- or Second-Line Treatment for HIV-1 Infection in Children.

BACKGROUND: Children with human immunodeficiency virus type 1 (HIV-1) infection have limited options for effective antiretroviral treatment (ART). METHODS: We conducted an open-label, randomized, noninferiority trial comparing three-drug ART based on the HIV integrase inhibitor dolutegravir with standard care (non-dolutegravir-based ART) in children and adolescents starting first- or second-line ART. The primary end point was the proportion of participants with virologic or clinical treatment failure by 96 weeks, as estimated by the Kaplan-Meier method. Safety was assessed. RESULTS: From September 2016 through June 2018, a total of 707 children and adolescents who weighed at least 14 kg were randomly assigned to receive dolutegravir-based ART (350 participants) or standard care (357). The median age was 12.2 years (range, 2.9 to 18.0), the median weight was 30.7 kg (range, 14.0 to 85.0), and 49% of the participants were girls. By design, 311 participants (44%) started first-line ART (with 92% of those in the standard-care group receiving efavirenz-based ART), and 396 (56%) started second-line ART (with 98% of those in the standard-care group receiving boosted protease inhibitor-based ART). The median follow-up was 142 weeks. By 96 weeks, 47 participants in the dolutegravir group and 75 in the standard-care group had treatment failure (estimated probability, 0.14 vs. 0.22; difference, -0.08; 95% confidence interval, -0.14 to -0.03; P = 0.004). Treatment effects were similar with first- and second-line therapies (P = 0.16 for heterogeneity). A total of 35 participants in the dolutegravir group and 40 in the standard-care group had at least one serious adverse event (P = 0.53), and 73 and 86, respectively, had at least one adverse event of grade 3 or higher (P = 0.24). At least one ART-modifying adverse event occurred in 5 participants in the dolutegravir group and in 17 in the standard-care group (P = 0.01). CONCLUSIONS: In this trial involving children and adolescents with HIV-1 infection who were starting first- or second-line treatment, dolutegravir-based ART was superior to standard care. (Funded by ViiV Healthcare; ODYSSEY ClinicalTrials.gov number, NCT02259127; EUDRACT number, 2014-002632-14; and ISRCTN number, ISRCTN91737921.).

Simplified dolutegravir dosing for children with HIV weighing 20 kg or more: pharmacokinetic and safety substudies of the multicentre, randomised ODYSSEY trial.

BACKGROUND: Paediatric dolutegravir doses approved by stringent regulatory authorities (SRAs) for children weighing 20 kg to less than 40 kg until recently required 25 mg and 10 mg film-coated tablets. These tablets are not readily available in low-resource settings where the burden of HIV is highest. We did nested pharmacokinetic substudies in patients enrolled in the ODYSSEY-trial to evaluate simplified dosing in children with HIV. METHODS: We did pharmacokinetic and safety substudies within the open-label, multicentre, randomised ODYSSEY trial (NCT02259127) of children with HIV starting treatment in four research centres in Uganda and Zimbabwe. Eligible children were randomised to dolutegravir in ODYSSEY and weighed 20 kg to less than 40 kg. In children weighing 20 kg to less than 25 kg, we assessed dolutegravir's pharmacokinetics in children given once daily 25 mg film-coated tablets (approved by the SRAs at the time of the study) in part one of the study, and 50 mg film-coated tablets (adult dose) or 30 mg dispersible tablets in part two of the study. In children weighing 25 kg to less than 40 kg, we also assessed dolutegravir pharmacokinetics within-subject on film-coated tablet doses of 25 mg or 35 mg once daily, which were approved by the SRAs for the children's weight band; then switched to 50 mg film-coated tablets once daily. Steady-state 24 h dolutegravir plasma concentration-time pharmacokinetic profiling was done in all enrolled children at baseline and 1, 2, 3, 4, 6, and 24 h after observed dolutegravir intake. Target dolutegravir trough concentrations (Ctrough) were based on reference adult pharmacokinetic data and safety was evaluated in all children in the corresponding weight bands who consented to pharmacokinetic studies and received the studied doses. FINDINGS: Between Sept 22, 2016, and May 31, 2018, we enrolled 62 black-African children aged from 6 years to younger than 18 years (84 pharmacokinetic-profiles). In children weighing 20 kg to less than 25 kg taking 25 mg film-coated tablets, the geometric mean (GM) Ctrough (coefficient of variation) was 0·32 mg/L (94%), which was 61% lower than the GM Ctrough of 0·83 mg/L (26%) in fasted adults on dolutegravir 50 mg once-daily; in children weighing 25 kg to less than 30 kg taking 25 mg film-coated tablets, the GM Ctrough was 0·39 mg/L (48%), which was 54% lower than the GM Ctrough in fasted adults; and in those 30 kg to less than 40 kg taking 35 mg film-coated tablets the GM Ctrough was 0·46 mg/L (63%), which was 45% lower than the GM Ctrough in fasted adults. On 50 mg film-coated tablets or 30 mg dispersible tablets, Ctrough was close to the adult reference (with similar estimates on the two formulations in children in the 20 to <25 kg weight band), with total exposure (area under the concentration-time curve from 0 h to 24 h) in between reference values in adults dosed once and twice daily, where safety data are reassuring, although maximum concentrations were higher in children weighing 20 kg to less than 25 kg than in the twice-daily adult reference. Over a 24-week follow-up period in 47 children on 30 mg dispersible tablets or 50 mg film-coated tablets, none of the three reported adverse events (cryptococcal meningitis, asymptomatic anaemia, and asymptomatic neutropenia) were considered related to dolutegravir. INTERPRETATION: Adult dolutegravir 50 mg film-coated tablets given once daily provide appropriate pharmacokinetic profiles in children weighing 20 kg or more, with no safety signal, allowing simplified practical dosing and rapid access to dolutegravir. These results informed the WHO 2019 dolutegravir paediatric dosing guidelines and have led to US Food and Drug Administration approval of adult dosing down to 20 kg. FUNDING: Paediatric European Network for Treatment of AIDS Foundation, ViiV Healthcare, UK Medical Research Council.