There were several great talks given on the final day of the ASHM conference. The morning HIV&AIDS symposium s100 prescriber session, entitled ‘changing landscapes in therapy’, discussed current and future issues pertaining to antiretroviral therapy, their interactions with other medications and their role in co-morbidities. Professor Mark Boyd from the University of Adelaide gave an interesting talk on ‘When is 2 drugs better than 3’. Antiretroviral therapy (ART) has often been referred to as ‘triple therapy’, reflecting the current guidelines and current practice of prescribing 3-drug combinations to achieve full virologic suppression.
This has come to question recently with a few trials completed or ongoing that assess dual therapy vs standard triple therapy. There are obvious benefits to dual therapy – reduced pill burden in the ageing cohort would have the effect of reduced drug interactions, as well as possibly improved adherence and drug tolerability. In the same session we heard from Ms Krista Siefred from St Vincent’s about polympharmacy and its associated adverse effects, as well as from pharmacist Ms Alison Duncan on the complexities of drug interactions between ART and other medications. Simplification of ART regimens would greatly assist in these matters
Mark presented several studies comparing dual therapy vs triple therapy. A meta-analysis was performed comparing this, looking at effect on dual vs triple therapy on virologic suppression. Overall, pooled results did not demonstrate a superior result for triple therapy over dual therapy for both viraemic patients and patients switching ART. In more recent studies using integrase inhibitors, again dual therapy (including a dlutegravir + lamivudine regimen, or an intramuscular cobotegravir + rilpivirine regimen) was shown to be non-inferior to standard triple therapy for virologic suppression.
Although interim data looks promising, long-term safety and efficacy of dual therapy is still yet to be fully examined. As such, it is not yet recommended for clinicians to routinely change patients to dual therapy regimens, although this switch may be a feasible option in the future.