Clinical impact of hiv-1 resistance against non-nucleoside analogue reverse transcriptase inhibitors
- Autores: Josep Maria Llibre Codina
- Directores de la Tesis: Bonaventura Clotet Sala (dir. tes.), Roger Paredes Deiros (codir. tes.), Jordi Tor Aguilera (tut. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2015
- Idioma: inglés
- Tribunal Calificador de la Tesis: Roberto Muga Bustamante (presid.), José María Gatell Artigas (secret.), Francesc Vidal Marsal (voc.)
- Materias:
- Enlaces
- Resumen
Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are popular components of antiretroviral therapy due to their efficacy and simplicity. Resistance is caused only by specific mutations at drug-resistance positions. Despite its proven efficacy, the clinical use of first-generation NNRTIs (nevirapine and efavirenz) has been limited by side effects and low barrier to resistance. To overcome these limitations, a second-generation of NNRTIs has been developed including etravirine and rilpivirine, both recently approved.
Rilpivirine also depicts a low barrier to resistance development. Like nevirapine and efavirenz, complete drug resistance can arise with only one or two resistance-associated mutations (RAMs). In addition, there is a considerable degree of class cross-resistance among all NNRTIs, nearly complete between nevirapine and efavirenz, and more limited from first to second generation NNRTIs. Therefore, the knowledge of RAMs selected by first-generation NNRTIs that have a potential to impact both rilpivirine or etravirine in subsequent treatments is of paramount importance.
Genotypic scores are now fully developed for all these drugs, therefore allowing resistance analyses in clinical samples and offering a unique opportunity to investigate the clinical impact of HIV-1 resistance on treatment response both in initial, salvage or simplification treatment.
In this PhD thesis, we discuss the relevance of RAMs on treatment response; we pinpoint the patterns of RAMs selected at virologic failure (VF) with specific NNRTIs, and the consequent risk of failure to salvage or simplification with NNRTIs.
The first chapter evaluates the effectiveness of etravirine in salvage regimens in VF recruited at four acute-care University hospitals in Barcelona. These regimens were generally well tolerated and achieved rates of virological suppression that exceed those observed in etravirine¿s pivotal clinical trials, probably due to the inclusion of a higher number of active drugs in the regimens. We identified baseline CD4+ T cell count >200 cells/mm3 and use of raltegravir and darunavir as factors associated with lower treatment failure rates using a multivariate analysis. We found no relationship between prior interruption or VF with nevirapine or efavirenz and response to etravirine.
The second chapter assesses the RAMs selected in subjects failing NNRTI-based treatments (with nevirapine, efavirenz or etravirine) at 22 clinics in Spain and the potential impact on rilpivirine¿s activity. Rilpivirine resistance was recognized in 20% of these patients, more commonly following etravirine or nevirapine failures than efavirenz. The most prevalent rilpivirine RAMs in subjects failing other NNRTIs were Y181C, K101E/P, H221Y and E138A/G/K. E138K/M184I, the most frequently selected combination in initial treatment with rilpivirine, was absent in this treatment-experienced population. L100I and V108I were significantly more frequent in efavirenz failures. Conversely, Y181C/I, V106A, H221Y and F227L were more prevalent in nevirapine ones.
Finally, the third chapter estimates the effectiveness of a nevirapine-based switch regimen in subjects with suppressed viremia, combined with tenofovir and emtricitabine (or lamivudine). The analysis has been done in our clinic in Barcelona. No unexpected RAMs or patterns of RAMs were selected in treatment failures to this regimen. At week 48, nearly 90% of the subjects had HIV-1 RNA <50 copies/mL, VF was uncommon, and 25 (7.4%) subjects discontinued the treatment due to toxicity. Factors independently associated with VF in multivariate analysis were intravenous drug use, time with undetectable viral load before the switch, number of prior NRTIs or NNRTIs, and previous nevirapine or efavirenz unscheduled interruptions. Reinitiation of nevirapine plus tenofovir plus emtricitabine (or lamivudine) should be discouraged in subjects experiencing unplanned treatment interruptions, even with an undetectable plasma viral load at the time of treatment withdrawal.
Unexpectedly, we found a significantly higher rate of VF with lamivudine instead of emtricitabine with this regimen, with a significantly higher selection of M184V as well. Our findings suggest caution against substituting emtricitabine for lamivudine, at least in nevirapine- and tenofovir-based regimens.
