A fifth of patients who start antiretroviral therapy with Atripla switch to an alternative regimen within a year, according to UK data presented to the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Chicago. The main reason for changing therapy was central nervous system side-effects.
Antiretroviral treatment guidelines in the UK recommend a combination of efavirenz (Sustiva) and FTC/tenofovir (Truvada) for patients starting HIV treatment. These drugs are available in a combined pill, Atripla, which is taken once daily.
Therapy with Atripla usually achieves durable HIV suppression. However, like all anti-HIV drugs it can cause side-effects. Most notably, efavirenz has been associated with mood and sleep disturbances such as depression, vivid dreams and nightmares. Often these are mild and transient and lessen or disappear after the first few weeks of therapy. However, for a minority of patients, these side-effects are so severe that a change in treatment is necessary.
With well over 20 licensed antiretroviral drugs, most of which are taken once daily and have a mild side-effect profile, there are several effective alternatives to Atripla.
Therefore, investigators from the Chelsea and Westminster Hospital in London wanted to establish the proportion of patients who stopped taking Atripla in the first twelve months of therapy.
They undertook a retrospective study, reviewing the notes of 472 individuals who initiated first-line Atripla therapy. Most of the patients were men (94%), their median age was 37 years, three-quarters were white and 52% were gay.
Baseline viral load and CD4 cell count were 16,000 copies and 285 cells/mm3 respectively.
The study confirmed the effectiveness of Atripla. After six months of treatment, 92% of patients had an undetectable viral load, and this had increased to 98% at month twelve. These high rates of virological suppression were accompanied by a strengthening of immune function, with median CD4 cell count increasing to 387 cells/mm3 after six months of therapy and 449 cells/mm3 after a year of treatment.
Modest increases in total cholesterol were observed (4.3 mmol/l at baseline, to 4.7 mmol/l at month six and 4.8 mmol/l at month twelve), but triglycerides remained largely unchanged at approximately 1.5 mmol/l.
However, despite these impressive outcomes, a total of 89 patients (19%) discontinued Atripla within a year of starting therapy.
The median duration of treatment before discontinuation was approximately ten months (294 days). Almost half (48%) of patients who stopped taking Atripla did so three to twelve months after starting therapy with the drug. However, 36% of patients of the patients who discontinued therapy did so after more than one year after commencing Atripla treatment.
Central nervous system toxicities were the most common reason for stopping treatment with the drug (71%). The most common mood and sleep disorders were depression, dizziness, insomnia and nightmares.
Other causes of treatment discontinuation included liver toxicity (7%), rash (7%), and virological failure or resistance (7%).
“Individuals on Atripla are often required to switch antiretroviral therapy,” conclude the researchers, “the commonest reason in our cohort was for CNS [central nervous system] toxicity with the majority of cases occurring after more than 3 months.”
Zheng J et al. Discontinuation of tenofovir, emtricitabine and efavirenz as a single tablet regimen in HIV-1 infected individuals naïve to antiretroviral therapy. 51st Interscience Conference on Antimicrobial Agents and Chemotherapy, abstract H2-783, Chicago, 2011. (Click here for the free abstract.)