[Two novel fixed formulations of nucleoside analogues (tenofovir-emtricitabine, and abacavir-lamivudine). Prospective, open study on clinical practice and therapeutic perspectives, in patients naïve and in subjects pre-treated with antiretrovirals].

The introduction of novel, fixed nucleoside-nucleotide reverse transcriptase inhibitor (NRTI) combinations (tenofovir-emtricitabine, and abacavir-lamivudine), expanded the spectrum of available formulations and increased patient's adherence. A prospective survey of the open-label use of these two fixed combinations was performed in 158 patients belonging to our single-centre cohort of over 1,000 HIV-infected subjects enrolled in the last 18 months, and followed for at least 12 months. During the last 18 months, 95 consecutive, evaluable patients (60.1%) received for the first time tenofovir-emtricitabine, or abacavir-lamivudine (63 patients, 39.9%), and were followed for at least 12 months. A major role seems to be played by tenofovir-emtricitabine in first-line treatments (preferably among "compact" regimens based on efavirenz), while the proportionally increased abacavir-lamivudine prescription to pre-treated patients is mostly attributable to the different genetic barrier of abacavir (often associated with boosted protease inhibitors, in this last patient group). The present availability to two more fixed NRTI combinations favored by their single pill, once-daily administration encourages randomized, controlled "head to head" studies in both first-line and experienced patients, in order to better exploit and target their therapeutic potential.