Switching from Combivir (AZT [zidovudine] and 3TC [lamivudine]) to Truvada (tenofovir and FTC [emtricitabine]) increases the chances of a patient achieving a viral load below 50 copies/ml, according to a study involving Gilead Sciences, the manufacturers of Truvada which was presented to the 45th Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington DC. The investigators also found that switching to Truvada led to a reduction in the number of patients reporting fatigue.
The 934 Study found that treatment-naive patients randomised to take Truvada with efavirenz had better virologic and immunologic responses, and were less likely to discontinue antiretroviral therapy than individuals randomised to receive Combivir and efavirenz.
Truvada is taken once daily, whilst Combivir is dosed twice daily.
Investigators wished to see if patients already taking Combivir who switched to Truvada experienced any change in their viral load, CD4 cell count and haemoglobin. The investigators also evaluated the impact of switching therapy on symptoms, levels of adherence and patient satisfaction. A 24 week prospective study was designed in which patients continued to take efavirenz in combination with Truvada meaning that the total pill burden was two pills once daily.
To enter the study, patients were required to have been taking Combivir for at least eight weeks and to have a viral load below 400 copies/ml.
A total of 217 individuals were recruited to the study and interim 24 week data for 198 patients (and 19 discontinuations) were presented to the conference. In total, 86% of these 82 patients were male, 71% were Caucasian and 22% African-American. The mean age of patients was 42 years, the median CD4 cell count at baseline was 578 cells cells/mm3 and median haemoglobin was 14.5g/dl. The overwhelming majority of patients (89%) had been been taking Combivir for over a year before they entered the study and switched to Truvada.
The principal reason for individuals opting to enter the study and switch from Combivir to Truvada was treatment simplification (86%).
Twenty-four weeks after changing treatment, 94% of patients still had a viral load below 400 copies/ml and 76% had a viral load below 50 copies/ml. The investigators note that the proportion of patients with a viral load below 50 copies/ml had increased significantly from the 59% at baseline (p
CD4 cell count remained unchanged, but median haemoglobin levels increased by 0.6g/dl from baseline (p
Modest but significant improvements in levels of total cholesterol, LDL cholesterol and triglycerides were also reported.
Changing treatment also seemed to be associated with improved quality of life. At baseline 65% of patients said that they were fatigued. This had fallen to 48% twelve weeks after the treatment switch (p = 0.002). Significant improvements in patient satisfaction and toleration of the regimen were also reported.
De Jesus E et al. Effects of switching from fixed dose zidovudine/lamivudine to fixed dose tenofovir/emtricitabine: maintenance of virologic suppression and other benefits. 45th Interscience Conference on Antimicrobial Agents and Chemotherapy, abstract H-517, Washington DC, 2005.