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Accounting for a Non-suppressed Viral Load

We incorporate the following score modifications if a patient is noted to have a non-suppressed viral load. [1]

We exclude EFV-containing regimens if there is a history (or current use) of EFV and the patient is not virally suppressed. We add a further penalty for NNRTI-containing regimens if the patient has a history of non-EFV NNRTI use and is not currently virally suppressed if there are less than two fully-active non-NNRTI drugs in the regimen (see below). 

NRTI Rules

Score Modification Rule
We penalized ABC/3TC + (NNRTI or PI) if the viral load was high or unknown
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Score Modification Rule
With history of treatment failure on NNRTIs, we penalized regimens with insufficient additional drugs with high barrier of resistance with concurrent use of an NNRTI
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We prioritized switching to 2 NRTI + PI +/- another ARV or 2 NRTI + INSTI +/- another ARV after treatment failure on an NNRTI regimen

In patients failing NNRTI therapy, there are clinical trial data to support the usage of: a)PI + NRTI or b)PI + INSTI. While this data is primarily for 2NRTI + LPV/r, or LPV/r + RAL, we have extrapolated to include other PIs (Baheyngyi et al) and INSTIs that may be better tolerated and with easier dosing schedules.

1)In the SECOND-LINE trial of 541 patients that had failed a first line NNRTI-based regimen, patients received either LPV/r + NRTI backbone (control) vs LPV/r + RAL, and both had comparable rates of viral suppression at 48 weeks (83% vs 81%)[2]  

2)Similar results were observed in the EARNEST trial(Paton et al., 2014) of 1277 patients failing first line NNRTI based regimens in sub-Saharan Africa; patients received PI monotherapy vs 2NRTI + LPV/r vs LPV/r + RAL. PI monotherapy did not meet criteria for non-inferiority, but the alternative regimens were non-inferior to each other, with 60% viral suppression and 64% viral suppression in the 2NRTI+PI and PI+INSTI arms, respectively[3]

3)Similar results were again seen in the phase III SELECT trial of 515 patients failing NNRTI based regimens, where LPV/R + RAL was non-inferior to LPV/R +NRTI[4]

4)In the STAR study[5] of 195 patients failing NNRTI-based regimens, many of them with M184V, TDF/3TC+LPV/r was superior with respect to viral suppression (83%) at 48 weeks, compared to LPV/r monotherapy.

6)Some experts would avoid a strategy of using less than 3 active drugs in this setting, except when including a boosted PI.

7) Evidence against the usage of NRTI + INSTI comes from the SWITCHMARK[6] study in which patients that were virally suppressed on a boosted PI that had their PI switched to RAL experienced more viral rebound (Viral suppression 84%) compared to those that stayed on a boosted PI (91%).  Whether this finding applies to DTG is unknown. These data suggest that a boosted PI +NRTI may be able to lead to adequate viral suppression even with compromised NRTI backbones, whereas perhaps a compromised background is not optimal when pairing NRTI with some INSTI such as RAL in viremic patients.In the SPIRAL study and VIKING-3 studies, DTG appeared to lead to viral suppression in a large proportion of patients that had multi class resistance.

We prioritized switching to PI + INSTI +/- another ARV after treatment failure on an NNRTI regimen
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We penalized switching to 2 NRTI + ETR +/- another ARV after treatment failure on an NNRTI regimen

5)Combining NRTIs with other NNRTI’s in patients failing first line NNRTI regimens has been shown to have suboptimal responses. Ruxrunghtam et al showed that in patients experiencing NNRTI failure, receipt of NRTI + ETR had lower rates of virological responses at week 12 compared to a strategy of NRTI + PI[7] 

We penalized 2 NRTI + RPV if the viral load was high or unknown

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PI Rules

Score Modification Rule
We prioritized remaining on 2 NRTI + PI +/- another ARV or switching to 2 NRTI + INSTI +/- another ARV after treatment failure on an PI regimen

When failing a boosted PI based regimen, failure is often due to poor adherence, drug-drug interactions, or drug-food interactions.

When failing a boosted PI + NRTI regimen, several studies have shown limited resistance to XTC (Lathouwers 2011, Stebbing 2007).  A systematic review has suggested that maintaining the same regimen, with improved adherence, may be effective (Zheng 2014). PI reseistance in this setting are also relatively rare (Daar 2011, Orkin 2013, Molina 2010).  As such, our algorithm prioritizes continuing the PI based regimen, or switching to a non-PI regimen with at least 2 fully active agents.


Score Modification Rule
We prioritized switching to 2 NRTI + PI +/- another ARV or PI + (DTG or BIC) +/- another ARV after treatment failure on an INSTI regimen

There is currently limited data on managing patients with first line failure of 2NRTIs + 1 INSTI.  In patients receiving 2NRTI + RAL, or 2NRTI + EVG/c, there may be emergent resistance to XTC and possibly the INSTI, but may retain sensitivity to DTG[8][9][10].  Failing in this scenario is often due to poor adherence.  DHHS guidance suggests that one can likely extrapolate based on NNRTI failure datea, suggesting that a boosted PI plus NRTI, or a PI plus INSTI (assuming no INSTI resistance) can be considered.  In the absence of data on usage of BIC/TAF/FTC after treatment failure, we penalized this regimen in the setting of prior failure on an INSTI regimen

Also, see section on INSTI+PI below.

We penalized INSTI + PI if the viral load was high or unknown
  • In the NEAT001/ANRS143 (N = 805) trial of Naive patients, DRV/r plus RAL was noninferior to TDF/FTC+DRV/r, but had lower efficacy in patients with high HIV-1 RNA/low CD4+ cell counts.
  • Efficacy in Clinical Trials

    Trial Name

    Drugs Compared


    Study Results


    DRV/r+DTG (1 arm)

    113 tx-experienced

    At week 48, the combination of DTG and DRV/r provided a high rate of viral suppression (98.1%), with only one dropout due to drug toxicity [11].

    Other Evidence in support of 1 INSTI + 1 PI:






    TDF/FTC + LPV/r vs LPV/r + RAL

    206 tx-naive

    The LPV/r + RAL regimen was found to be noninferior to the regimen of LPV/r + TDF/FTC in both safety and efficacy. Viral suppression at 48 weeks 83% in RAL group vs 85% in TDF/FTC+LPV/r group[12]


    RAL + ATV vs TDF/FTC+ATV/r

    94 tx-naive

    Similar rates of viral suppression at 24 weeks, but higher incidence of hyperbilirubinemia and RAL resistance development[13]


    DRV/r + RAL

    112 tx-naive

    26% virologic failure by 48 weeks, with integrase resistance in 5 participants, particularly in those with baseline viral load>100,000[14]


    DRV/r+ RAL vs TDF/FTC+DRV/r

    68 tx-naive

    DRV/r+RAL was less effective than DRV/r+TDF/FTC (62.5% of RAL subjects and 83.7% of TDF/FTC subjects were responders (VL<48 copies/mL) at week 48) but better for bone health. However, the proportions of patients achieving VL<200 copies/mL were similar: 72.5% and 86.0%[15]

    ANRS143/NEAT 100

    DRV/r+RAL vs


    805 tx-naive

    DRV/r+RAL was noninferior for the primary endpoint of time to treatment failure (17.8%vs 13.8% at 96 weeks); planned subgroup analysis showed RAL arm was inferior for those with CD4<200.[16]

Active Drug Rules

Score Modification Rule
In treatment experienced patients with detectable viral loads, we severely penalized regimens with ≤ 1 active drugs and moderately penalized regimens with > 1 but < 2 active drugs. We slightly penalized regimens with ≥ 2 but < 3 active drugs and prioritized regimens with 3 or more active drugs.
Overall, the goal of treatment in ART experienced patients experiencing virologic failure is to establish virologic suppression (DHHS Guidelines 2016).  DHHS panel recommends that "at least 2, and preferably three full active agents" should be included, in which a "fully active agent is one that is expected to have uncompromised activity on the basis of the patient’s treatment history and drug-resistance testing results and/or the drug’s novel mechanism of action"
We additionally prioritized two drug regimens that contained fully active DRVDTG, or BIC

In the DAWNING trial, 627 patients failing first line NNRTI regimens (> 6 months) with at least one active NRTI were randomized to 2WHO recommended NRTIs + DTG VS. 2NRTI's +LPV/RTV.  WHO recommend ZDV + 3TC after failure of first-line TDF + 3TC or FTC; TDF + 3TC or FTC after first-line ZDV or d4T + 3TC.At Week 24, DTG+2NRTIs was superior to LPV/r+2NRTIs, with 82%  and 69%, respectively, achieving HIV-1 RNA <50 c/mL (p<0.001). The difference was mainly driven by lower rates of Snapshot virologic non-response in the DTG group. 56% (347/624) of subjects received WHO-recommended second-line NRTIs, and their response rates within each arm were higher than those for subjects who did not. Regardless of WHO-recommended NRTI use, response rates were higher with DTG versus LPV/r-based regimens (Table).  In this analysis, there were no treatment-emergent primary integrase-strand transfer inhibitor or NRTI resistance mutations in the DTG group through the randomisation phase.

In a Swedish cohort of 244 patients with preexisting NRTI's and DTG (with a control cohort of PLWH on PI/r and one or two NRTI's with matched genotype susceptibility scores) were followed.  Median observation time was 78 weeks (interquartile range 50–98 weeks) for participants on DTG and 75 weeks (50–101 weeks) for individuals on PI/r. Viral failure was detected in four individuals treated with DTG and three individuals treated with PI/r, resulting in similar success rates of 96.7% and 97.5%, respectively. No new mutations were found among participants with treatment failure. DTG in combination with one to two NRTIs was as efficient as PI/r in individuals with pre-existing NRTI mutations in this setting. (Sorstedt et al. May 2018 IJAA)