Effectiveness, Safety, and Tolerability of a Switch to Dual Therapy with Dolutegravir Plus Cobicistat-Boosted Darunavir in Treatment-Experienced Patients with Human Immunodeficiency Virus

Effectiveness and Tolerability of Dual Therapy with Dolutegravir Plus Darunavir/cobicistat in Treatment-Experienced Patients with HIV: A 144-Week Follow-Up

BACKGROUND

A dual regimen with dolutegravir plus cobicistat-boosted darunavir (DTG+DRV/c) is a promising alternative for patients with human immunodeficiency virus (HIV) with resistance or intolerance to nucleoside reverse transcriptase inhibitors, especially those with a history of treatment failure.

MATERIALS AND METHODS

We included all treatment-experienced patients with HIV who switched to the DTG+DRV/c regimen at a tertiary university hospital. We assessed the regimen's effectiveness, safety, and tolerability through serial laboratory data and clinical findings. The primary endpoint was the proportion of patients with plasma HIV-RNA levels <50 copies/mL at week 144 post-switch. The secondary endpoints were safety and tolerability assessments.

RESULTS

Our retrospective analysis involved 40 patients. The leading reasons for switching to DTG+DRV/c were treatment failure in 17 patients (42.5%), simplification after multiple previous regimens in 15 (37.5%), and adverse drug reactions in 8 (20.0%). Among the 17 patients in the treatment failure group, we observed enhanced viral suppression and improved CD4+ T-cell counts after initiating the dual regimen. In the non-treatment failure group (23 patients), viral suppression and CD4+ T-cell levels were consistently maintained. No significant alterations in renal function, liver function, glucose levels, or lipid profiles were observed post-switch. High tolerability was observed, with 34/40 patients (85.0%) responding well to the regimen. However, six patients discontinued treatment before reaching the 144-week mark.

CONCLUSION

Our findings confirm that DTG+DRV/c is an effective and well-tolerated switch therapy regimen for treatment-experienced patients with HIV, with sustained benefits observed for up to 144 weeks of follow-up. This regimen showed adaptability across different patient groups and demonstrated virological and immunological improvements, particularly in patients with a history of treatment failure.

Outcome of Darunavir-Cobicistat-Based Regimens in HIV-Infected People Who Have Experienced Virological Failure

Objective

To evaluate the virological outcome of darunavir-cobicistat (DRVc)-based regimens in adults living with HIV who had experienced virological failure (VF) on any previous drug combination.

Methods

This was a retrospective cohort study (CSLHIV Cohort) of adults living with HIV who started a DRVc-based regimen with HIV-RNA >50 copies/mL after VF on any previous drug combination. Data on demographics, antiretroviral treatment since HIV diagnosis, and immunological and metabolic parameters from baseline (start of DRVc) to 48 weeks were analyzed in order to assess the cumulative proportion of those who achieved virological success (VS), defined as at least one instance of HIV-RNA <50 copies/mL within 12 months from baseline. Follow-up lasted from the start of the DRVc-based regimen (baseline) to the first instance of HIV-RNA <50 copies/mL, last available visit, or loss to follow-up or death, whichever occurred first. Univariate and multivariate Cox proportional-hazard regression models were used to identify baseline factors associated with VS.

Results

A total of 176 individuals were included, and 120 (68.2%) achieved <50 HIV-RNA copies/mL within 12 months since baseline. On multivariate analysis, baseline HDL cholesterol was independently associated with the occurrence of VS (adjusted HR 1.021, 95% CI 1.004-1.038; p=0.014). Among the 120 subjects with VS, 27 (22.5%) had had VF during a median follow-up of 20.8 months since the first undetectable HIV-RNA. Resistance testing after VF was available in two cases, which harboured the HIV variant-bearing protease inhibitor-resistance mutations D30N, I50V, and N88D. During a median follow-up of 38.4 months, 65 of 176 (36.9%) individuals discontinued DRVc for any reason (37 of 120, 30.8%) and achieved VS vs. 28 of 56 (50%) without VS (p=0.019). Time to discontinuation was longer in people with VS (41.5 vs. 23.0 months, p=0.0007). No statistically significant changes were observed in immunological or lipid profiles during follow-up.

Conclusion

Most individuals in this study achieved VS within 12 months from the beginning of a DRVc-based regimen; therefore, this treatment represent a viable option for people who have experienced VF on other regimens.

Dolutegravir-Based Dual Therapies in HIV Pretreated Patients: A Real-Life Study in Madrid

BACKGROUND

Few studies describe the use of dolutegravir (DTG)-based dual therapies under routine clinical practice.

OBJECTIVES

To report real-life data on the use of DTG-based dual therapies in treatment-experienced patients.

METHODS

This was an observational, retrospective study. It included all treatment-experienced HIV patients starting a DTG-based dual therapy from 2014 to 2018. The primary end point was to identify the incidence and reasons for the switch. The secondary end points were to assess the effectiveness, safety, adherence, and costs after 48 weeks of treatment (W48).

RESULTS

The incidence of the switch to a DTG-based dual therapy increased from 1.6 patients per 1000 patient-years in 2014 to 38.6 in 2018. A total of 241 patients initiated this therapy: 113 (46.9%) patients started DTG plus rilpivirine (RPV), 72 (29.9%), DTG plus lamivudine (3TC), and 68 (28.2%), DTG plus boosted-darunavir (b-DRV). A total of 170 patients completed W48 of follow-up. By intention-to-treat analysis, 89.3% of virologically suppressed (VS) patients (94.3% with DTG plus b-DRV, 91.3% with DTG plus 3TC, and 87.2% with DTG plus RPV) and 56.7% of non-VS patients (71.4% with DTG plus RPV and 52.2% with DTG plus b-DRV) achieved a viral load <50 copies/mL at W48. The protocol-defined virological failure was 6.5%. Overall, 8.8% of patients had early discontinuation. The annual cost increased by €800 per patient ($916).

CONCLUSIONS AND RELEVANCE

The use of DTG-based dual therapies has increased in real life, showing a favorable effectiveness and safety profile. Treatment costs increased, except for the switch to DTG plus 3TC.

Effectiveness of boosted darunavir plus rilpivirine in patients with long-lasting HIV-1 infection: DARIL study

BACKGROUND

The combination of boosted darunavir plus rilpivirine, once daily, could be a convenient, effective and well-tolerated two-drug regimen to achieve HIV suppression in HIV-infected patients.

METHODS

Multicentre, retrospective cohort study in nine hospitals in Spain. All HIV-infected subjects starting boosted darunavir plus rilpivirine were included, irrespective of their viral load (VL). The primary objective was the percentage of patients with VL <50 copies/mL at 48 weeks. Secondary objectives included changes in CD4+ cell count, lipid profile and renal function.

RESULTS

Eighty-one of 84 patients reached Week 48. Fifty-nine (70.2%) patients had VL <50 copies/mL at baseline and the rest had a median VL of 202 (IQR 98-340) copies/mL. Subjects had a median of 21 years of infection with six prior regimens. The main reasons for starting boosted darunavir plus rilpivirine were simplification (44%), kidney or bone toxicity (28.6%) and virological failure (17.9%). Historical genotypes from 47 patients showed 41 (87.2%) patients with NRTI RAMs, 21 (44.7%) with NNRTI RAMs, 12 (25.5%) with primary PI RAMs and 7 (14.9%) with integrase strand transfer inhibitor (INSTI) RAMs. One patient had low-level resistance to boosted darunavir and five patients had some resistance to rilpivirine. At 48 weeks, 71 (87.7%) patients had VL <50 copies/mL. According to undetectable or detectable baseline VL, effectiveness was 91.1% or 80%, respectively. There were four virological failures with no emergence of new RAMs. Three of these patients resuppressed viraemia while maintaining the same regimen.

CONCLUSIONS

The combination of boosted darunavir plus rilpivirine has shown good effectiveness and tolerability in this cohort of pretreated patients with a long-lasting HIV infection, exposure to multiple antiretroviral regimens and prior HIV resistance.

Risks and benefits of reducing the number of drugs to treat HIV-1 infection

Introduction: Despite the efficacy and safety of antiretroviral therapy, new treatment options are needed to address the concerns of patients and physicians regarding long-term toxicities, costs, and convenience of lifelong antiretroviral therapy. To achieve this goal, one strategy is to reduce the number of drugs in the antiretroviral regimen.Areas covered: We review the recent evidence on the efficacy and safety of reduced drug regimens and their potential risks and benefits. There is currently strong evidence showing that some two-drug regimens have a comparable efficacy and short-term safety compared to standard three-drug regimens. The fixed-dose combination of dolutegravir/lamivudine is already an alternative for many treatment-naïve and virologically suppressed HIV-1 infected adults supported by large randomized clinical trials. The co-formulation dolutegravir plus rilpivirine is also a switch strategy for maintenance therapy. Long-acting injectable cabotegravir plus rilpivirine has already regulatory approval, and islatravir plus doravirine is an expected option in the near future. Some two-drug regimens have not been as successful.Expert opinion: Long-term safety issues of these two-drug regimens remain to be determined, but with the overwhelming evidence available in virological control and short-term safety, the potential benefits of some of these two-drug regimens appear to outweigh the risks.

Virological response and resistance profile in highly treatment-experienced HIV-1-infected patients switching to dolutegravir plus boosted darunavir in clinical practice

OBJECTIVES

We evaluated the virological response and resistance profile in combined antiretroviral therapy (cART)-experienced HIV-1-infected patients starting a dual therapy with dolutegravir (DTG) and boosted darunavir (bDRV) for the first time.

METHODS

Survival analyses were used to evaluate virological success (VS) and virological rebound (VR) in viraemic and virologically suppressed patients, respectively. Major resistance mutations (MRMs) and genotypic susceptibility score (GSS) were evaluated at baseline and after switch.

RESULTS

Overall, 130 patients [62 (47.7%) viraemic; 68 (52.3%) virologically suppressed] were retrospectively analysed. At the moment of switch, 81.5% accumulated one or more MRM [protease inhibitor (PI), 35.7%; nucleoside(t)ide reverse transcriptase inhibitor (NRTI), 77.5%; non-NRTI, 69.0%; integrase inhibitor (INI), 10.1%), but 77.7% harboured strains fully susceptible to DTG + bDRV. In viraemic patients, the overall probability of VS by 12 months of treatment was 91.7%. In virologically suppressed patients, the overall probability of VR was 10.5% by 24 months after therapy start. Patients with previous time under virological suppression ≤ 6 months showed a higher VR probability compared with others (37.5% vs. 6.7%, P < 0.002). Among 13 non-responding patients for whom a genotypic resistance test result at failure was available, only two (15.4%) accumulated further resistance in integrase (Y143C/H/R; S147G and N155H) and protease (V32I, L33F, I54L).

CONCLUSIONS

In highly treatment-experienced patients, the use of dual therapy based on DTG + bDRV appears to be a very good regimen for switch therapy, with a high rate of virological control in both viraemic and virologically suppressed patients. Among non-responding patients, the selection of further resistance is a rare event.

Boosted darunavir and dolutegravir dual therapy among a cohort of highly treatment-experienced individuals

BACKGROUND

The use of dual antiretroviral therapy (ART) regimens for treatment of HIV is increasing. The contemporary combination of boosted darunavir with dolutegravir has not been widely studied.

METHODS

This was a retrospective cohort study that evaluated treatment-experienced individuals within three large urban clinics prescribed boosted darunavir with dolutegravir (study regimen) dual therapy. Follow-up was defined as the number of days from regimen initiation until the last HIV RNA determination on the study regimen. Virological outcomes, HIV RNA ≤50 copies/ml (undetectable), were assessed overall and by baseline HIV RNA status.

RESULTS

Of 65 individuals included, 83% were at least 3-class antiretroviral-experienced and median time since starting ART was 19 years (IQR 13-22). Median follow-up was 419 days (IQR 286-744). An undetectable HIV RNA was achieved by 62/65 (95%) individuals at any time point on the study regimen. At the end of follow-up 61/65 (94%) individuals remained undetectable, including 48/49 (98%) with an undetectable HIV RNA at baseline (those changing for optimization) and 13/16 (81%) with viraemia at baseline (those changing therapy during virological failure). At the end of follow-up, 55 (85%) individuals were still taking the study regimen. No individuals stopped therapy due to virological failure or intolerance.

CONCLUSIONS

In a highly treatment-experienced cohort, boosted darunavir with dolutegravir dual therapy demonstrated high rates of virological success, even in those with detectable HIV RNA prior to initiating the study regimen. Further study of this potent, simple, high-barrier dual-class regimen is warranted.

A systematic review of the genetic mechanisms of dolutegravir resistance

Background

Characterizing the mutations selected by the integrase strand transfer inhibitor (INSTI) dolutegravir and their effects on susceptibility is essential for identifying viruses less likely to respond to dolutegravir therapy and for monitoring persons with virological failure (VF) on dolutegravir therapy.

Methods

We systematically reviewed dolutegravir resistance studies to identify mutations emerging under dolutegravir selection pressure, the effect of INSTI resistance mutations on in vitro dolutegravir susceptibility, and the virological efficacy of dolutegravir in antiretroviral-experienced persons.

Results and conclusions

We analysed 14 studies describing 84 in vitro passage experiments, 26 studies describing 63 persons developing VF plus INSTI resistance mutations on a dolutegravir-containing regimen, 41 studies describing dolutegravir susceptibility results, and 22 clinical trials and 16 cohort studies of dolutegravir-containing regimens. The most common INSTI resistance mutations in persons with VF on a dolutegravir-containing regimen were R263K, G118R, N155H and Q148H/R, with R263K and G118R predominating in previously INSTI-naive persons. R263K reduced dolutegravir susceptibility ∼2-fold. G118R generally reduced dolutegravir susceptibility >5-fold. The highest levels of reduced susceptibility occurred in viruses containing Q148 mutations in combination with G140 and/or E138 mutations. Dolutegravir two-drug regimens were highly effective for first-line therapy and for virologically suppressed persons provided dolutegravir’s companion drug was fully active. Dolutegravir three-drug regimens were highly effective for salvage therapy in INSTI-naive persons provided one or more of dolutegravir’s companion drugs was fully active. However, dolutegravir monotherapy in virologically suppressed persons and functional dolutegravir monotherapy in persons with active viral replication were associated with a non-trivial risk of VF plus INSTI resistance mutations.

High predictive efficacy of integrase strand transfer inhibitors in perinatally HIV-1-infected African children in therapeutic failure of first- and second-line antiretroviral drug regimens recommended by the WHO

Objectives

The predictive efficacy of integrase (IN) strand transfer inhibitors (INSTIs) was investigated in HIV-infected children born to HIV-infected mothers in Africa.

Methods

Plasma was collected at the Complexe Pédiatrique of Bangui, Central African Republic, from INSTI-naive children (n = 8) and adolescents (n = 10) in virological failure (viral load >1000 copies/mL) after 5 years of first- and/or second-line combination ART (cART). IN, reverse transcriptase (RT) and protease (P) genes were genotyped and drug resistance mutations (DRMs) to INSTIs, NRTIs, NNRTIs and PIs were interpreted using the Stanford algorithm.

Results

Successful IN, RT and P genotypes were obtained for 18, 13 and 15 children (median age 11 years, range 5–18; 8 were female), respectively. Two (2/18; 11.1%) viruses from children treated with a first-line regimen had INSTI DRMs at codon 138 (E138K and E138T), which is known to harbour major resistance mutations, and also had the accessory mutations L74I, G140K, G140R and G163R. The majority (16/18; 88.9%) of HIV-1 IN sequences demonstrated full susceptibility to all major INSTIs with a high frequency of natural polymorphic mutations. Most (12/15; 80%) genotyped viruses harboured at least one major DRM conferring resistance to at least one of the WHO-recommended antiretroviral drugs (NNRTIs, NRTIs and PIs) prescribed in first- and second-line regimens.

Conclusions

INSTIs could be proposed in first-line regimens in the majority of African children or adolescents and may constitute relevant therapeutic alternatives as second- and third-line cART regimens in HIV-infected children and adolescents living in sub-Saharan Africa.

Two's a Company, Three's a Crowd: A Review of Initiating or Switching to a Two-Drug Antiretroviral Regimen in Treatment-Naïve and Treatment-Experienced Patients Living with HIV-1

INTRODUCTION

As HIV has become a manageable chronic condition, a renewed and increased interest in challenging traditional three-drug HIV therapies and moving toward two-drug regimens (2DR) for initial or maintenance treatment in people living with HIV (PLWH) has developed. As PLWH are living longer, continual advancements in antiretroviral regimens have been a focus to provide optimal life-long therapy options. Although early studies may have shown poor outcomes in virologic suppression with 2DR, newer studies and treatment options have emerged to show promise in the management of HIV. The purpose of this review is to evaluate current literature and assess the efficacy of two-drug (2DR) antiretroviral therapy in treatment-naïve and -experienced people living with HIV.

METHODS

A systematic search was performed between January 2009 to January 2020, using EMBASE, MEDLINE, Google Scholar, and bibliographies. Combinations of the following search terms were used: HIV-1 infection, antiretroviral therapy, dual therapy, two-drug regimen, two-drug therapy, two-drug regimen, and 2DR. Included studies were those in the adult population with at least one active comparator, outcomes assessing HIV-1 RNA viral load while on treatment, and written in English.

RESULTS

Thirty-three studies were included, 13 where 2DRs were evaluated as initial therapy (3 studies with extension data) and 15 where 2DRs were evaluated as maintenance or switch therapy (2 studies with extension data).

CONCLUSION

Although 2DRs may not be appropriate in all patient populations, they are being utilized more frequently and have the potential to reduce costs, adverse effects, and drug interactions.

Synthesis and Characterization of Long-Acting Darunavir Prodrugs

Antiretroviral therapy (ART) has improved the quality of life in patients infected with HIV-1. However, complete viral suppression within anatomical compartments remains unattainable. This is complicated by adverse side effects and poor adherence to lifelong therapy leading to the emergence of viral drug resistance. Thus, there is an immediate need for cellular and tissue-targeted long-acting (LA) ART formulations. Herein, we describe two LA prodrug formulations of darunavir (DRV), a potent antiretroviral protease inhibitor. Two classes of DRV prodrugs, M1DRV and M2DRV, were synthesized as lipophilic and hydrophobic prodrugs and stabilized into aqueous suspensions designated NM1DRV and NM2DRV. The formulations demonstrated enhanced intracellular prodrug levels with sustained drug retention and antiretroviral activities for 15 and 30 days compared to native DRV formulation in human monocyte-derived macrophages. Pharmacokinetics tests of NM1DRV and NM2DRV administered to mice demonstrated sustained drug levels in blood and tissues for 30 days. These data, taken together, support the idea that LA DRV with sustained antiretroviral responses through prodrug nanoformulations is achievable.