Are Prophylactic and Therapeutic Target Concentrations Different?: the Case of Lopinavir-Ritonavir or Lamivudine Administered to Infants for Prevention of Mother-to-Child HIV-1 Transmission during Breastfeeding

Preventing breast milk HIV transmission using broadly neutralizing monoclonal antibodies: One size does not fit all

Passive immunoprophylaxis with broadly neutralizing monoclonal antibodies (bNAbs) could be a game changer in the prevention of human immunodeficiency virus (HIV) acquisition. The prevailing view is that available resources should be focused on identifying a fixed combination of at least three bNAbs for universal use in therapeutic and preventive protocols, regardless of target populations or routes of transmission. HIV transmission through breastfeeding is unique: it involves free viral particles and cell‐associated virus from breast milk and, in the case of acute/recent maternal infection, a viral population with restricted Env diversity. HIV transmission through breastfeeding in high incidence/prevalence areas could potentially be eliminated by subcutaneous administration to all newborns of one or two long‐acting bNAbs with extended breadth, high potency, and effector properties (ADCC, phagocytosis) against circulating HIV strains.

Pharmacokinetics and Safety of the Abacavir/Lamivudine/Lopinavir/Ritonavir Fixed-Dose Granule Formulation (4-in-1) in Neonates: PETITE Study

BACKGROUND

Antiretroviral options for neonates (younger than 28 days) should be expanded. We evaluated the pharmacokinetics, safety, and acceptability of the "4-in-1" fixed-dose pediatric granule formulation of abacavir/lamivudine/lopinavir/ritonavir (30/15/40/10 mg) in neonates.

METHODS

The PETITE study is an ongoing phase I/II, open-label, single-arm, 2-stage trial conducted in South Africa. In stage 1, term neonates exposed to HIV on standard antiretroviral prophylaxis (nevirapine ± zidovudine) received single dose(s) of the 4-in-1 formulation, followed by intensive pharmacokinetic sampling and safety assessments. At each PK visit, blood was drawn after an observed dose at 1, 2, 4, 8, and 12 hours postdose. In this study, we have reported the planned interim pharmacokinetic and safety analysis after completion of the single-dose administration.

RESULTS

Sixteen neonates, with a median (range) birth weight of 3130 g (2790-3590 g), completed 24 pharmacokinetic visits. The 4-in-1 formulation imposed relatively high doses of abacavir [8.6 mg/kg (6.6-11.4)] and lamivudine [4.3 mg/kg (3.3-5.7)] but lower doses of lopinavir [11.5 mg/kg (8.8-15.2)]. The geometric means (GM, 90% CI) AUC0-12 of abacavir, lamivudine, and lopinavir were 29.87 (26.29-33.93), 12.61 (10.72-14.83), and 3.49 (2.13-5.72) µg.h/mL, respectively. Lopinavir GM AUC0-12 was below the predefined target (20-100 µg.h/mL), and ritonavir concentrations were only detectable in 4 of the 120 (3%) samples. No adverse events were related to study drugs. No neonate had difficulty swallowing the 4-in-1 formulation.

CONCLUSIONS

The high doses of abacavir and lamivudine (in mg/kg) and AUCs were safe, and the formulation was well tolerated; however, lopinavir/ritonavir exposures were extremely low, preventing its use in neonates use in neonates. Alternative pediatric solid antiretroviral formulations must be studied in neonates.

Inhibition of CYP3A7 DHEA-S Oxidation by Lopinavir and Ritonavir: An Alternative Mechanism for Adrenal Impairment in HIV Antiretroviral-Treated Neonates

Prophylactic antiretroviral therapy (ART) in HIV infected pregnant mothers and their newborns can dramatically reduce mother-to-child viral transmission and seroconversion in the neonate. The ritonavir-boosted lopinavir regimen, known as Kaletra, has been associated with premature birth and transient adrenal insufficiency in newborns, accompanied by increases in plasma dehydroepiandrosterone 3-sulfate (DHEA-S). In the fetus and neonates, cytochrome P450 CYP3A7 is responsible for the metabolism of DHEA-S into 16α-hydroxy DHEA-S, which plays a critical role in growth and development. In order to determine if CYP3A7 inhibition could lead to the adverse outcomes associated with Kaletra therapy, we conducted in vitro metabolic studies to determine the extent and mechanism of CYP3A7 inhibition by both ritonavir and lopinavir and the relative intrinsic clearance of lopinavir with and without ritonavir in both neonatal and adult human liver microsomes (HLMs). We identified ritonavir as a potent inhibitor of CYP3A7 oxidation of DHEA-S (IC₅₀ = 0.0514 μM), while lopinavir is a much weaker inhibitor (IC₅₀ = 5.88 μM). Furthermore, ritonavir is a time-dependent inhibitor of CYP3A7 with a K_I of 0.392 μM and a k_inact of 0.119 min^–1, illustrating the potential for CYP3A mediated drug–drug interactions with Kaletra. The clearance rate of lopinavir in neonatal HLMs was much slower and comparable to the rate observed in adult HLMs in the presence of ritonavir, suggesting that the addition of ritonavir in the cocktail therapy may not be necessary to maintain effective concentrations of lopinavir in neonates. Our results suggest that several of the observed adverse outcomes of Kaletra therapy may be due to the direct inhibition of CYP3A7 by ritonavir and that the necessity for the inclusion of this drug in the therapy may be obviated by the lower rate of lopinavir clearance in the neonatal liver. These results may lead to a reconsideration of the use of ritonavir in neonatal antiretroviral therapy.

Early initiation of antiviral therapy contributes to a rapid and significant loss of serum HBsAg in infantile-onset hepatitis B

BACKGROUND & AIM

There is a paucity of data regarding antiviral therapy in hepatitis B virus (HBV)-infected infants aged <1 year who have elevated alanine aminotransferase. This study aims to assess the efficacy and safety of antiviral therapy initiated in infancy.

METHODS

A real-world cohort study was conducted from January 2010 to December 2017. HBV-infected infants under 1 year of age, with persistent elevation of alanine aminotransferase and high viral load, were recruited and divided into 2 groups. Group I included 18 infants whose parents chose to initiate antiviral therapy with lamivudine before 1 year of age. Group II included 11 infants whose parents chose to initiate antiviral therapy with interferon-α after 1 year of age and not to receive any antiviral therapies before 1 year of age. The main outcome measure was rate of serum HBV surface antigen (HBsAg) loss at month 12 of treatment.

RESULTS

There were no statistical differences between Groups I and II regarding baseline characteristics. No infants in Group II developed spontaneous HBsAg loss before 1 year of age. In Group I, the cumulative rates of HBsAg loss at month 3, 6, 9 and 12 of treatment were 39%, 67%, 78% and 83%, respectively. In Group II, the cumulative rates of HBsAg loss at month 3, 6, 9 and 12 of treatment were 18%, 27%, 27% and 36%, respectively. Statistical differences existed in the cumulative rates of HBsAg loss between the 2 groups (log-rank test, p = 0.0023). No serious adverse events occurred in the study.

CONCLUSION

Early initiation of antiviral therapy for infantile-onset hepatitis B contributes to a rapid and significant loss of HBsAg. Further trials with larger cohorts are needed to verify our results.

LAY SUMMARY

Chronicity is a serious threat to infants infected with hepatitis B. However, no treatment measure has been recommended for infantile-onset hepatitis B in current guidelines. In order to evaluate the benefit and safety of antiviral therapy in infantile-onset hepatitis B, a real-world cohort study was conducted. Long-term follow-up results showed that early initiation of antiviral therapy with lamivudine safely led to a rapid and significant loss of serum hepatitis B surface antigen in the present subset of infants with alanine aminotransferase ≥2× upper limit of normal. Further trials with larger cohorts are needed.

Growth in HIV-1-exposed but uninfected infants treated with lopinavir-ritonavir versus lamivudine: a secondary analysis of the ANRS 12174 trial

BACKGROUND

The tolerance of antiretroviral drugs in infants must be carefully evaluated. In previous studies of children with HIV type 1 (HIV-1) less weight gain was observed in children given lopinavir-ritonavir-based combinations than those given nevirapine. We aimed to compare the effects of lopinavir-ritonavir and lamivudine on growth in HIV-exposed uninfected infants included in the ANRS 12174 trial.

METHODS

ANRS 12174 was a multicentre, randomised, controlled trial of infant prophylaxis to prevent HIV-1 transmission by breastfeeding done at four antenatal clinics in Burkina Faso, South Africa, Uganda, and Zambia. HIV-exposed uninfected infants born to asymptomatic mothers not eligible for antiretroviral therapy (CD4 count >350 cells per μL) were randomly assigned (1:1) to receive lopinavir-ritonavir or lamivudine 7 days after birth, with stratification by country. In a prespecified secondary analysis, we assessed the effect of lopinavir-ritonavir and lamivudine on the growth of these infants from day 7 until cessation of breastfeeding (maximum treatment time 12 months) in the modified intention-to-treat population, which included all children correctly enrolled with at least one follow-up anthropometric measurement. We compared the growth of infants, defined as children's WHO-defined length-for-age Z score (LAZ), weight-for-length Z score (WAZ), and weight-for-age Z score (WLZ). We used linear mixed effect and β spline-regression models to compare growth between the treatment groups. The trial is registered with ClinicalTrials.gov, number NCT00640263.

FINDINGS

1273 HIV-exposed uninfected infants and their mothers were enrolled between Nov 16, 2009, and May 7, 2013, of whom 1266 (99%) infants were included in the modified intention-to-treat analysis (630 assigned to lopinavir-ritonavir, 636 assigned to lamivudine). Baseline characteristics of the infants and mothers were similar across the two treatment groups. No differences in least-squares (LS) mean LAZ were identified between the treatment groups at any timepoint. LS mean WLZ was significantly lower in the lopinavir-ritonavir group than the lamivudine group at 26 weeks (difference -0·22 [95% CI -0·34 to -0·09], p=0·0006) and 50 weeks (-0·25 [-0·47 to -0·04], p=0·02). LS mean WAZ was also significantly lower in the lopinavir-ritonavir group than the lamivudine group at 26 weeks (difference -0·18 [95% CI -0·30 to -0·05], p=0·01) and 50 weeks (-0·24 [-0·45 to -0·05], p=0·02). Linear mixed models showed that lopinavir-ritonavir was associated with decreases in WLZ and WAZ over time (p<0·0001 and p=0·002), whereas spline regression models indicated that these reductions occurred early and remained constant thereafter (p<0·0001 with a knot at 44 days for WLZ; p=0·02 with a knot at 118 days for WAZ). The difference in LS mean WLZ at 50 weeks between the treatment groups was higher among girls than boys (difference -0·29 [95% CI -0·58 to 0·01], p=0·05 for girls; -0·22 [-0·53 to 0·09], p=0·18 for boys).

INTERPRETATION

Less weight gain was observed in infants given lopinavir-ritonavir than those given lamivudine, which is indicative of a persistent effect that could have long-term deleterious effects. This finding merits attention considering the recommendations for early and lifelong treatment of infants with HIV.

FUNDING

French National Agency for Research on AIDS and Viral Hepatitis, the Total Foundation, the European Developing Countries Clinical Trials Partnership, and the Research Council of Norway.