Induction and maintenance therapy

This treatment strategy involves starting with a highly potent combination regimen for the first six to twelve months (the induction regimen), then subtracting some of the drugs once most of the virus population has been eliminated (the maintenance regimen).

In some patients, especially those starting treatment for the first time, the idea is that once viral load has been brought down to an undetectable level, a less intensive regimen may keep HIV under control over the long term. However, if the maintenance regimen is not potent enough, there is a real risk that the virus could bounce back, known as viral ‘breakthrough’ or ‘rebound'.

The use of four-drug, three-class combinations has been explored as part of an induction and maintenance strategy.

In the FORTE study, more than 100 treatment-naive patients were randomly assigned to receive a standard three-drug regimen containing two NRTIs plus one NNRTI or induction and maintenance therapy.

Those in the latter arm started with a four-drug, three-class regimen consisting of two NRTIs, one NNRTI and one protease inhibitor for 24 to 32 weeks, until viral load was suppressed below 50 copies/ml, then they stopped the protease inhibitor. People in the induction and maintenance arm were half as likely to experience virological failure after about 80 weeks of follow-up, and none developed protease resistance mutations.1

In the M03-613 study, 155 treatment-naive patients were randomly assigned to start lopinavir/ritonavir or efavirenz, both with AZT/3TC. Those in the lopinavir/ritonavir arm stopped the NRTIs if they achieved sustained viral suppression. After 72 weeks, 50% of the patients taking lopinavir/ritonavir monotherapy had a viral load below 50 copies/ml, compared to 61% in the efavirenz combination arm (not a statistically significant difference). However, patients in the monotherapy arm were significantly more likely to experience viral load ‘blips’, and 13% developed protease resistance mutations.2

In the COOL trial, French researchers studied 143 people who had been on HIV treatment for an average of about four years and had a viral load below 50 copies/ml. At study enrolment they switched to either tenofovir/3TC/efavirenz or just tenofovir/efavirenz. After 48 weeks, 97% in the three-drug arm maintained viral suppression compared with 82% in the two-drug arm, and those who experienced treatment failure developed NNRTI resistance mutations. Cholesterol and triglyceride levels did not change in either arm, and more people actually dropped out due to side-effects in the group taking fewer drugs.3

Protease inhibitor monotherapy has also been explored as a component of an induction and maintenance strategy. This approach, and those discussed above, remains experimental and is not recommended outside the setting of a clinical trial.

References

  1. Loveday C et al. Adding a PI for 6 months to a standard NNRTI-based regimen reduces the risk of virological failure without inducing resistance to the PI: a FORTE virology analysis. Twelfth Conference on Retroviruses and Opportunistic Infections, abstract 575, 2005
  2. Cameron W et al. A two-year randomized controlled clinical trial in antiretroviral-naïve subjects using lopinavir/ritonavir (LPV/r) monotherapy after initial induction treatment compared to an efavirenz (EFV) 3-drug regimen (Study M03-613). 16th International AIDS Conference, Toronto, abstract THLB0201, 2006
  3. Girard PM et al. Tenofovir DF + efavirenz (TDF+EFV) vs tenofovir DF+ efavirenz + lamivudine (TDF+EFV+3TC) maintenance regimen in virologically controlled patients: COOL Trial. 46th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco, abstract H-1383, 2006
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap
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This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.