Efficacy and safety of tipranavir coadministered with ritonavir in HIV-1-infected children and adolescents: 5 years of experience

Long-term safety, tolerability and antiviral activity of rilpivirine in antiretroviral-naïve adolescents living with HIV-1, aged 12 to less than 18 years: Week 240 findings of a phase 2, open-label study, PAINT

This phase 2 study investigated long-term safety and efficacy of rilpivirine (RPV) plus two investigator-selected nucleos(t)ide reverse transcriptase inhibitors (NRTIs) in HIV-1-infected antiviral therapy-naive adolescents. Participants (≥12 to <18 years of age) were treated with RPV at 25 mg once daily (q.d.) plus 2 NRTIs and entered the treatment extension period for up to 240 weeks, with visits every 3 months. Long-term safety (analysis of adverse events [AEs] and laboratory results), efficacy (virologic response and outcome for patients with viral loads of <50 and <400 by time to loss of virologic response [TLOVR] and FDA Snapshot methods, as well as CD4⁺ cell count), and adherence (by pill count) for up to 240 weeks are presented. Twenty-four of 36 participants entered the treatment extension period, and 21 completed week 240. At week 240, a viral load of <50 copies/mL was achieved by 14/32 (43.8%) participants; virologic response by TLOVR was higher in participants with a baseline viral load of ≤100,000 copies/mL (48.0%) versus a viral load of >100,000 copies/mL (28.6%). By FDA Snapshot, a viral load of <50 copies/mL at week 240 was found in 53.1% (17/32) of participants with a baseline viral load of ≤100,000 copies/mL. Higher response was observed in participants with adherence of >95% and a baseline viral load of ≤100,000 copies/mL. Through week 240, 16/32 participants (50.0%) experienced virologic failure, including seven who developed treatment-emergent RPV resistance-associated mutations (RAMs [frequently E138K]): all 7 had ≥1 treatment-emergent NRTI RAM. No serious AEs after week 48, no discontinuations due to AEs between week 48 and week 240, and no new safety signals were observed. RPV did not affect pubertal development or adolescent growth. At the 5-year follow-up, efficacy was low in adolescents, particularly those with poor adherence and/or a high baseline viral load of >100,000 copies/mL. To limit the risk of virologic failure, RPV is restricted to patients with a baseline VL of ≤100,000 copies/mL in most countries. In addition, adequate treatment adherence to RPV treatment is imperative for long-term viral suppression and should be emphasized in the management of adolescents living with HIV. RPV exhibited a favorable long-term safety profile for adolescents living with HIV-1 with adequate adherence. (This study has been registered at ClinicalTrials.gov under identifier NCT00799864.)

Pharmacokinetics and pharmacodynamics of cytochrome P450 inhibitors for HIV treatment

INTRODUCTION

Drugs used in HIV treatment; all protease inhibitors, some non-nucleoside reverse transcriptase inhibitors, and pharmacoenhancers ritonavir and cobicistat can inhibit cytochrome P450 (CYP) enzymes. CYP inhibition can cause clinically significant drug-drug interactions (DDI), leading to increased drug exposure and potential toxicity. Areas covered: A complete understanding of pharmacodynamics and CYP-mediated DDI is crucial to prevent adverse side effects and to achieve optimal efficacy. We summarized the pharmacodynamics of all the CYP inhibitors used for HIV treatment, followed by a discussion of drug interactions between these CYP inhibitors and other drugs, and a discussion on the effect of CYP polymorphisms. We also discussed the potential advancements in improving the pharmacodynamics of these CYP inhibitors by using nanotechnology strategy. Expert opinion: The drug-interactions in HIV patients receiving ARV drugs are complicated, especially when patients are on CYP inhibitors-based ART regimens. Therefore, evaluation of CYP-mediated drug interactions is necessary prior to prescribing ARV drugs to HIV subjects. To improve the treatment efficacy and minimize DDI, novel approaches such as nanotechnology may be the potential alternative approach. However, further studies with large cohort need to be conducted to provide strong evidence for the use of nano-formulated ARVs to effectively treat HIV patients.

Treatment Outcomes of Third-line Antiretroviral Regimens in HIV-infected Thai Adolescents

BACKGROUND

Efficacy and safety data of third-line antiretroviral (ARV) regimens in adolescents are limited.

METHODOLOGY

This study enrolled HIV-infected Thais who were treated with third-line regimens consisting of darunavir/ritonavir (DRV/r), etravirine (ETR), tipranavir/ritonavir or raltegravir.

RESULTS

Fifty-four adolescents 2-17 years of age were enrolled from 8 sites and followed for 48 weeks. Reasons for switch were second-line failure (n = 44) and toxicity to second-line regimens (n = 10). At switching to third-line ARV, the median age (interquartile range) was 14.3 (12.4-15.4) years. Genotypes at time of second-line failure (n = 44) were M184V (77%), ≥4 thymidine analogue mutations (25%), non-nucleoside reverse transcriptase inhibitor-resistant associated mutation (RAM) (80%), ETR-RAM score ≥4 (14%), any lopinavir-RAM (59%) and ≥1 major DRV-RAM (41%). The third-line regimens had a median of 4 (min-max, 4-6) drugs and included ETR/DRV/r (43%), DRV/r (33%), ETR (17%), tipranavir/ritonavir (2%) or raltegravir/DRV/r/ (4%). The median CD4 (interquartile range) increased from 16% (12-21) at third-line switch to 21% (18-25) and 410 (172-682) to 607 (428-742) cells/mm at 48 weeks (P < 0.001). HIV RNA declined from 3.9 (2.9-4.9) to 1.6 (1.6-3.0) log10 copies/mL (P < 0.001) and 33/50 (66%) had levels <50 copies/mL at 48 weeks. Seventeen (31%) had HIV-RNA ≥1000 copies/mL; about half due to poor adherence; genotyping in 13 of these adolescents revealed ETR-RAM score ≥4 in 2 (15%) and ≥1 major DRV-RAM in 7 (54%).

CONCLUSIONS

Third-line ARV therapy was well tolerated and resulted in virologic suppression in 70% of adolescents at 1 year. Poor adherence and limited ARV options are major problems in the long-term management of adolescents with HIV.