For clinicians who would like to simplify their patients’ HAART regimens (highly active retroviral therapies) by replacing the protease inhibitor (PI), nevirapine (Viramune drug, Boehringer Ingelheim) or efavirenz (Sustiva drug, Bristol-Myers Squibb Oncology) might be a better choice than abacavir (Ziagen®, Glaxo-SmithKline), according to the Nevira-pine/Efavirenz/Abacavir Study Team.
The researchers randomly assigned 460 adults who were virologically steady (maintaining plasma HIV-1 RNA levels below 200 copies/ml for at least six months) to switch from their current PI:
155 patients were switched to nevirapine, 156 were switched to generic efavirenz, and 149 were switched to abacavir.
At 12 months, despite virological failure (the inability to achieve or maintain viral suppression) in 19 patients, 117 patients were still taking nevirapine, 112 were still taking efavirenz, and 113 were still taking abacavir. Sixteen abacavir patients experienced virological failure while taking the study medication, compared with eight in the canadian nevirapine group and five in the efavirenz group. At 12 months, two abacavir patients had progressed to acquired immunodeficiency syndrome (AIDS).
Patients who had previously had a “suboptimal” response to therapy with nucleoside reverse-transcriptase inhibitors (NRTIs) were more likely to do poorly with abacavir: 23 of the 29 patients with virological failure taking the study drug had received suboptimal prior therapy. However, patients who had done well had similar rates of viral suppression when they were switched to a study drug.
Although approximately 50% of the patients in each group experienced adverse drug effects (ADEs), patients taking abacavir were less likely to discontinue their study drug because of ADEs.