HIV Salvage Therapy Does Not Require Nucleoside Reverse Transcriptase Inhibitors: A Randomized, Controlled Trial

Structural cumulative survival models for estimation of treatment effects accounting for treatment switching in randomized experiments

Treatment switching in a randomized controlled trial occurs when a patient in one treatment arm switches to another arm during follow-up. This can occur at the point of disease progression, whereby patients in the control arm may be offered the experimental treatment. It is widely known that failure to account for treatment switching can seriously bias the estimated treatment causal effect. In this paper, we aim to account for the potential impact of treatment switching in a reanalysis evaluating the treatment effect of nucleoside reverse transcriptase inhibitors (NRTIs) on a safety outcome (time to first severe or worse sign or symptom) in participants receiving a new antiretroviral regimen that either included or omitted NRTIs in the optimized treatment that includes or omits NRTIs trial. We propose an estimator of a treatment causal effect for a censored time to event outcome under a structural cumulative survival model that leverages randomization as an instrumental variable to account for selective treatment switching. We establish that the proposed estimator is uniformly consistent and asymptotically Gaussian, with a consistent variance estimator and confidence intervals given, whose finite-sample performance is evaluated via extensive simulations. An R package 'ivsacim' implementing all proposed methods is freely available on R CRAN. Results indicate that adding NRTIs versus omitting NRTIs to a new optimized treatment regime may increase the risk for a safety outcome.

Long-term Outcomes in a Large Randomized Trial of HIV-1 Salvage Therapy: 96-Week Results of AIDS Clinical Trials Group A5241 (OPTIONS)

BACKGROUND

Short-term (48-week) results of the OPTIONS trial showed that nucleoside reverse transcriptase inhibitors (NRTIs) can be safely omitted from salvage therapy as long as the regimen has a cumulative activity of >2 active antiretroviral medications. The long-term durability of this approach and outcomes in persons who have more-extensive HIV-1 drug resistance are uncertain.

METHODS

Participants with virologic failure and anticipated antiretroviral susceptibility received an optimized regimen and were randomized to omit or add NRTIs. A separate group with more resistance (cumulative activity ≤2 active agents) received an optimized regimen including NRTIs.

RESULTS

At week 96, among 360 participants randomized to omit or add NRTIs, 70% and 65% had HIV-1 RNA <200 copies/mL, respectively. Virologic failure was uncommon after week 48. Younger age and starting fewer new antiretroviral medications were associated with higher odds of virologic failure. In the highly resistant group, 53% had HIV-1 RNA <200 copies/mL at week 96.

CONCLUSIONS

HIV-1 salvage therapy can safely omit NRTIs without compromising efficacy or durability of response as long as the new regimen has a cumulative activity of >2 active drugs. Younger people and those receiving fewer new antiretrovirals require careful monitoring. Even among individuals with more-extensive resistance, most achieve virologic suppression.

CLINICAL TRIALS REGISTRATION

NCT00537394.

Maintenance of virologic suppression and improvement in comorbidities after simplification to raltegravir plus boosted darunavir among treatment-experienced HIV-infected patients

The use of two potent, well-tolerated, drugs could permit the maintenance of virologic suppression even in heavily pretreated people living with HIV. In this retrospective, multicenter, simplification study (NCT03348449), we included those patients with virologic suppression who switched to raltegravir (RAL) plus boosted darunavir (b/DRV). Overall, 345 patients (75 females, 25%) were included. Patients were largely pretreated (mean, 9.4 regimens), suppressed for a median of 41.1 months. Fifty patients had ≥1 mutation against DRV. At 96 weeks, the efficacy by intention-to-treat analysis (snapshot) was 73% (95%CI, 68.4–77.8%), but 97.1% (95%CI, 95.4–98.9) excluding changes due to non-virologic reasons, and virologic failure was rare (0.9%; 95%CI, 0.1–1.2%). Median CD4/CD8 ratio increased from 0.59 to 0.62 (p < 0.01), CD4+ cell count by +90 cells/µl (p < 0.01), and mean estimated glomerular filtration rate (eGFR) increased from 85.2 to 88.5 ml/min at 96 weeks, greater for patients receiving tenofovir disoproxil fumarate (eGFR, +3.6 ml/min, p = 0.04; serum phosphate +0.33 mg/dl; p < 0.01). There was a continued and significant improvement in the total cholesterol/high-density lipoprotein-cholesterol ratio. In conclusion, the simplification to a dual regimen with the combination of RAL and b/DRV is associated with maintenance of virologic suppression, even in largely pretreated patients, with improvements in CD4+ cell count, CD4/CD8 ratio, and in renal and lipid parameters.

Management of Virologic Failure and HIV Drug Resistance

Approximately 20% of people with HIV in the United States prescribed antiretroviral therapy are not virally suppressed. Thus, optimal management of virologic failure has a critical role in the ability to improve viral suppression rates to improve long-term health outcomes for those infected and to achieve epidemic control. This article discusses the causes of virologic failure, the use of resistance testing to guide management after failure, interpretation and relevance of HIV drug resistance patterns, considerations for selection of second-line and salvage therapies, and management of virologic failure in special populations.

Third-line antiretroviral therapy in low-income and middle-income countries (ACTG A5288): a prospective strategy study

BACKGROUND

Antiretroviral therapy (ART) management is challenging for individuals in resource-limited settings presenting for third-line treatment because of complex resistance patterns, partly due to reduced access to viral load monitoring. We aimed to evaluate use of newer antiretroviral drugs and contemporary management approaches, including population-based sequencing, to select appropriate antiretrovirals, plasma viral load monitoring, and interventions to improve adherence in individuals presenting with second-line viral failure.

METHODS

A5288 was a phase 4, third-line ART strategy study done at 19 urban sites in ten countries that enrolled adult participants with confirmed plasma HIV-1 RNA (viral load) of 1000 copies per mL or more after more than 24 weeks of protease inhibitor-based second-line ART. The primary objective was to use antiretrovirals (raltegravir, etravirine, and ritonavir-boosted darunavir) and diagnostic monitoring technologies, including viral load, genotyping, and adherence support to achieve viral load suppression (defined as ≤200 copies per mL) in 65% or more of participants. ART history and real-time drug resistance genotypes were used to assign participants to one of four cohorts: cohort A (no lopinavir resistance) stayed on second-line ART and cohorts B (B1, best available nucleoside reverse transcriptase inhibitors [NRTIs] plus ritonavir-boosted darunavir plus raltegravir; B2, ritonavir-boosted darunavir plus raltegravir plus etravirine; B3, ritonavir-boosted darunavir, raltegravir, and either tenofovir plus emtricitabine or tenofovir plus lamivudine), C (ritonavir-boosted darunavir plus raltegravir plus tenofovir-emtricitabine or tenofovir plus lamivudine), and D (best available NRTIs plus ritonavir-boosted darunavir plus raltegravir) were defined by increasing levels of resistance and received appropriate regimens, including new antiretrovirals. Participants in Cohort B without detectable hepatitis B surface antigen were assigned by blocked randomisation to cohorts B1 and B2, and those with detectable hepatitis B surface antigen were assigned to cohort B3. The trial is registered with ClinicalTrials.gov, number NCT01641367.

FINDINGS

From Jan 10, 2013, to Sept 10, 2015, 545 participants were enrolled. 287 (53%) were assigned to cohort A, 74 (14%) to B1, 72 (13%) to B2, eight (1%) to B3, 70 (13%) to C, and 34 (6%) to D. Overall, 349 (64%, 95% CI 60-68) participants achieved viral suppression at week 48, with proportions varying from 125 (44%) of 287 in cohort A to 65 (88%) of 74 in cohort B1, 63 (88%) of 72 in B2, eight (100%) of eight in B3, 63 (90%) of 70 in C, and 25 (74%) of 34 in D. Participants in cohort A remained on their second-line protease inhibitor, and had the most participants with grade 3 or higher adverse events (147 [51%]).

INTERPRETATION

Targeted real-time genotyping to select third-line ART can appropriately allocate more costly antiretrovirals to those with greater levels of HIV drug resistance.

FUNDING

National Institutes of Health.

Dual antiretroviral therapy with tenofovir (TDF) and darunavir/ritonavir (DRV/RTV) in an HIV-1 positive patient: a case report, review, and meta-analysis of the literature on dual treatment strategies using protease inhibitors in combination with an NRTI

BACKGROUND

Here, we report the case of an HIV positive patient under a dual antiretroviral drug regimen with tenofovir disoproxil and darunavir/ritonavir with stable clinical, virological, and immunological response over 126 weeks. Dual antiretroviral therapy has the advantage of reduced toxicity and lower health care costs, treatment failure and fostering drug resistance are perceived risks. Optimal drug combinations and indication criteria for dual treatment remain controversial. Nevertheless, first clinical trials indicate non-inferiority for combinations of nucleoside reverse transcriptase inhibitors and protease inhibitors. This case presents the combination of tenofovir disoproxil in combination with a protease inhibitor as a new potential dual treatment regimen.

METHOD

We performed a systematic literature search and meta-analysis of trials comparing dual to triple ART.

RESULTS

Literature review revealed nine studies in which dual therapy with a protease inhibitor and an NRTI was compared to triple therapy. We performed a meta-analysis of six trials that reported a 48-week follow-up. In treatment-naïve patients as well when ART switch was assessed, there was no difference in the treatment success in patients with dual ART versus triple.

CONCLUSION

We conclude that dual therapy with a protease inhibitor and NRTI is safe and effective. The use of tenofovir in dual treatment as described in our case needs to be assessed in future clinical trials.

A dual regimen of ritonavir/darunavir plus dolutegravir for rescue or simplification of rescue therapy: 48 weeks' observational data

BACKGROUND

Dolutegravir (DTG) plus darunavir/ritonavir (DRV/r) is a simple combination of drugs that has the best genetic barrier to HIV-1 resistance and may be fit for salvage therapy.

METHODS

All HIV-1-infected subjects treated with DTG plus DRV/r between March 2014 and September 2015 in eight Italian centres were included in the analysis. The main metabolic data, efficacy parameters and safety data routinely collected were provided. This observational study is aimed to assess the efficacy of such approach. The primary end-point was the proportion of subjects achieving or maintaining virologic suppression <50 copies/mL at week 24. Secondary end points were maintaining virologic suppression in the follow-up (weeks 48 and 96) and safety.

RESULTS

One hundred and thirty subjects were followed for a median of 56 months. Reasons for switching were simplification (44.6%), viral failure (30%), toxicity (16.9%), non-adherence (4.6%), persistent low-level viremia (3.1%), and drug-drug interaction (0.8%). At baseline, 118 subjects had documented resistance to 1 to 5 antiretroviral classes while 12 had viral rebound at a time when genotypic tests were not yet available. Seventeen and 14 subjects took DRV/r and DTG twice daily, respectively. One subject was lost to follow-up, one discontinued for liver enzymes' elevation, one died of illicit drug abuse and one of cancer-related complications. The proportion of subjects with ongoing HIV replication dropped from 40% to 6.1%. Those with undetectable viral load increased from 38.5% to 76.2%. At week 48, 17.7% had HIV RNA between 1 and 49 copies/mL. The number of subjects with altered serum glucose, creatinine, ALT, AST, total-, HDL- and LDL-cholesterol, triglycerides and MDRD <90 mL/min decreased by week 48, while those having MDRD <60 mL/min remained 4.6%. Overall 90/283 baseline laboratory alterations returned to normality.

CONCLUSIONS

Switching to DTG plus DRV/r proved to be safe, suppressing viral replication without metabolic impact.