Estrella Caballero

Rilpivirine Resistance Mutations in HIV Patients Failing Non-Nucleoside Reverse Transcriptase Inhibitor-Based Therapies

Objective:Rilpivirine (RPV) is the latest approved nonnucleoside reverse transcriptase inhibitor (NNRTI). It displays in-vitro activity extending over other NNRTI-resistant HIV strains. There is scarce information about the rate of RPV resistance-associated mutations (RAMs) in patients failing other NNRTIs. Methods:RPV RAMs were examined in plasma samples collected from HIV patients that had recently failed NNRTI-based regimens at 22 clinics in Spain. Results:Resistance tests from a total of 1064 patients failing efavirenz (EFV) (54.5%), nevirapine (NVP) (40%) or etravirine (ETR) (5.5%) were examined. The prevalence of RPV RAMs was K101E (9.1%), K101P (1.4%), E138A (3.9%), E138G (0.3%), E138K (0.3%), E138Q (0.8%), V179L (0.2%), Y181C (21.8%), Y181I (0.5%), Y181V (0.2%), H221Y (8.3%), F227C (0.1%) and M230L (1.5%). K101E/M184I was seen in 1%. E138K/M184I were absent. Mutations L100I and V108I were significantly more frequent in patients failing EFV than NVP (7.9 vs. 0.2 and 12.2 vs. 7.3%, respectively). Conversely, Y181C, Y181I, V106A, H221Y and F227L were more prevalent following NVP than EFV failures. Using the Spanish resistance interpretation algorithm, 206 genotypes (19.3%) from patients failing NNRTI (NVP 52%, EFV 40.8% and ETR 7.8%) were considered as RPV resistant. In patients with ETR failure, cross-resistance to RPV was seen in 27.6%, mainly as result of Y181C (81.3%), V179I (43.8%), V90I (31.3%) and V108I (18.8%). Conclusion:RPV resistance is overall recognized in nearly 20% of patients failing other NNRTIs. It is more common following ETR (27.6%) or NVP (25%) failures than EFV (14.5%). E138 mutants are rarely seen in this context.

Drug resistance mutations in patients infected with HIV-2 living in Spain

BACKGROUND In contrast with HIV-1, information about drug resistance in HIV-2 is scarce and mainly derived from small series of patients failing antiretroviral therapy. METHODS The spectrum of changes in the reverse transcriptase (RT), protease (PR) and integrase (INT) genes was examined in HIV-2 individuals enrolled in the HIV-2 Spanish register. RESULTS From a total of 236 HIV-2-infected individuals registered in Spain from 1989 to June 2010, 53 PR, 44 RT and 8 INT sequences were obtained. Low plasma viraemia precluded collection of this information from most of the remaining cases. No major mutations associated with drug resistance in HIV-1 were recognized in 29 PR, 20 RT and 5 INT sequences from antiretroviral-naive HIV-2 individuals, although natural polymorphisms with potential effects on susceptibility to PR inhibitors were recognized at 10 positions (L10V/I, V32I, M36I, M46I, I47V, Q58E, A71V/I, G73A, V82I and L89I/V) and for nucleoside reverse transcriptase inhibitors at three positions (T69N, V75I and K219E). In 24 antiretroviral-experienced patients with virological failure the most frequent major RT resistance mutations were M184V (58%), Q151M (33%) and K65R (21%), which are rarely seen thymidine analogue mutations. In PR the most frequent major changes were V47A (17%), I54M (17%), I82F (13%), L90M (29%) and L99F (29%). Two of the three patients who failed on raltegravir had N155H in the INT region. CONCLUSIONS Drug resistance mutations in HIV-2 are selected at the same positions as in HIV-1, although with different frequency. Polymorphisms in the RT and PR associated with drug resistance in HIV-1 as compensatory changes are common in untreated HIV-2 subjects. These findings highlight the need for specific guidelines for interpreting genotypic resistance patterns in HIV-2 infection.

Efficacy and safety of nucleoside reverse transcriptase inhibitor-sparing salvage therapy for multidrug-resistant HIV-1 infection based on new-class and new-generation antiretrovirals

BACKGROUND The advent of new antiretrovirals has expanded the therapeutic options for multiple drug-resistant HIV-1 infection. The role of recycled nucleoside reverse transcriptase inhibitors (NRTIs) in this scenario remains uncertain. METHODS Observational study of 122 consecutive patients with prior triple-class failure and multidrug-resistant HIV infection who started a salvage regimen with at least three of the new antiretrovirals darunavir, etravirine, raltegravir and maraviroc. Virological, immunological and clinical outcomes were compared according to the inclusion or not of NRTIs in the regimen, after 48 weeks of follow-up. RESULTS All patients received at least two and 65% received three fully active drugs in the salvage regimen. In 63 patients recycled NRTIs were added to new drugs (NRTI-containing group) and 59 patients did not receive NRTIs (NRTI-sparing group). Both groups were comparable at baseline regarding the number of prior failures, resistance profile, CD4 cell count and HIV plasma viral load. The rates of HIV-1 RNA suppression below 50 copies/mL at week 48 (intent-to-treat analysis) were similar in the two groups: 46/59 [78%, 95% confidence interval (CI) 67%-88%] in the NRTI-sparing group and 49/63 (78%, 95% CI 67%-88%) in the NRTI-containing group. No significant differences were found in CD4 cell count increases. Drug-related adverse events leading to drug discontinuations only occurred in the NRTI-containing group (5 of 63, NRTI-related in 3 cases). CONCLUSIONS The addition of NRTIs with reduced activity, according to genotypic resistance tests, does not seem to improve the efficacy of salvage regimens containing three of the new antiretrovirals in patients with multidrug-resistant HIV-1 infection.

X4 tropic viruses are on the rise in recent HIV-1 seroconverters in Spain.

Background:Transmission of HIV-1 with drug resistance mutations (DRMs) in Spain remains stable around 13%. However, the profile of recent HIV-1 seroconverters has experienced significant changes. Methods:Retrospective analyses of all individuals with HIV-1 infection acquired within the past 12 months recruited at a national registry since year 1997. Results:A total of 1032 recent HIV-1 seroconverters were examined (92.2% men; median age 31 years; 84% homosexual men). At the moment of diagnosis, median plasma HIV-RNA and CD4+ cell counts were 4.5 log copies/ml and 558 cells/&mgr;l, respectively. A total of 136 individuals (13.8%) carried non-B subtypes. Major primary DRMs were found in 13.4%, being 7.7% for nucleoside reverse transcriptase inhibitor (NRTI), 5.8% for nonnucleoside reverse transcriptase inhibitor (NNRTI) and 2.9% for protease inhibitor. NRTI DRM significantly declined from 23.7% in 1997–2000 to 5.7% in 2010–2012 (P < 0.01). Overall, X4 viruses were found in 19.7% of HIV-1 seroconverters, increasing from 11.5% before 2001 to 23.3% since year 2010 (P = 0.04). Interestingly, median CD4+ cell counts were significantly lower in seroconverters diagnosed during the last period after adjusting for potential confounders. In multivariate analyses, X4 tropism, high HIV-RNA, foreigners and non-B subtypes were independent predictors of lower CD4+ cell counts. Conclusion:Transmission of NRTI DRM has declined significantly in recent HIV-1 seroconverters in Spain. Conversely, X4 tropic viruses are on the rise and currently account for 23.3% of new HIV-1 infections. These individuals present with lower CD4+ cell counts suggesting that circulating HIV-1 strains might have gained virulence.

Prevalence of Transmitted Antiretroviral Resistance and Distribution of HIV-1 Subtypes Among Patients with Recent Infection in Catalonia (Spain) between 2003 and 2005

OBJECTIVES The objectives of this study were to assess the prevalence of transmitted HIV-1 drug resistances (TDR) and HIV-1 subtypes in recently infected patients in Catalonia between 2003 and 2005 and to describe the characteristics of these patients according to the presence or absence of TDR and HIV-1 subtype. METHODS After application of the Serological Testing Algorithm for Recent HIV Seroconversion (STARHS), residual aliquots of serum samples from recently infected antiretroviral-naïve individuals were genotyped. FASTA sequences were analyzed using the HIVDB Program. The World Health Organization 2009 List of Mutations for Surveillance of Transmitted HIV-1 Drug Resistant HIV Strains was used to estimate the prevalence of TDR. RESULTS Of 182 recently infected patients, 14 (7.7%) presented TDR. Seven (3.8%) had genotypic evidence of TDR against non-nucleoside reverse transcriptase inhibitors, 6 (3.3%) against nucleoside reverse transcriptase inhibitors, 3 (1.6%) against protease inhibitors (PIs), and only 2 individuals (1.1%) presented TDR against more than one class of drugs. Thirty-five (19.2%) patients were infected with a non-B HIV-1 subtype. CONCLUSION This is the first study to estimate the prevalence of TDR in recently infected patients in Catalonia. The results are similar to those of studies performed in other Spanish regions. Correct monitoring of these parameters requires systematic epidemiologic surveillance of transmitted resistance.

Identification of recent HIV-1 infection among newly diagnosed cases in Catalonia, Spain (2006-08)

BACKGROUND Quantification and description of patients recently infected by HIV can provide an accurate estimate of the dynamics of HIV transmission. Between 2006 and 2008 in Catalonia, we estimated the prevalence of recent HIV infection among newly diagnosed cases, described the epidemiological characteristics of the infection according to whether it was recent, long-standing or advanced, and identified factors associated with recent infection. METHODS A Test for Recent Infection (TRI) was performed in serum samples from patients newly diagnosed with HIV. Two different TRI were used: the Vironostika-LS assay (January 2006-May 2007) and the BED-CEIA CEIA (June 2007 onwards). Samples were obtained within the first 6 months of diagnosis. Patients whose samples tested positive in the TRI were considered recently infected. RESULTS Of 1125 newly diagnosed patients, 79.9% were men (median age, 35.4 years), 38.7% were born outside Spain, 48.9% were men who have sex with men (MSM) and 10.6% presented other sexually transmitted infections. The overall percentage of recent infection was 23.0%, which increased significantly, from 18.1% in 2006 to 26.2% in 2008. This percentage was higher for patients from South America (27.6%). Factors associated with recent infection were acquiring infection through sexual contact between MSM [odds ratio (OR) 2.0; 95% confidence interval (95% CI) 1.1-3.9], compared with acquiring infection through heterosexual relations and being under 30 years of age (OR 5.9; 95% CI 1.9-17.4), compared with being over 50 years of age. CONCLUSION The highest percentage of recent infection was identified in MSM, suggesting either a higher incidence or a greater frequency of HIV testing. Information regarding testing patterns is necessary to correctly interpret data from recently infected individuals. Systems to monitor the HIV epidemic should include both parameters.

HIV-2 viral tropism influences CD4+ T cell count regardless of viral load

BACKGROUND HIV-2 infection is characterized by low plasma viraemia and slower progression to AIDS in comparison with HIV-1 infection. However, antiretroviral therapy in patients with HIV-2 is less effective and often fails to provide optimal CD4 recovery. METHODS We examined viral tropism in persons with HIV-2 infection enrolled in the HIV-2 Spanish cohort. Viral tropism was estimated based on V3 sequences obtained from plasma RNA and/or proviral DNA. RESULTS From a total of 279 individuals with HIV-2 infection recorded in the Spanish national register, 58 V3 sequences belonging to 42 individuals were evaluated. X4 viruses were recognized in 14 patients (33%). Patients with X4 viruses had lower median CD4+ cell counts than patients with R5 viruses [130 (17-210) versus 359 (180-470) cells/mm(3); P = 0.007]. This was true even considering only the subset of 19 patients on antiretroviral therapy [94 (16-147) versus 184 (43-368) cells/mm(3); P = 0.041]. In multivariate analysis, significant differences in CD4+ cell counts between patients with X4 and R5 viruses remained after adjusting for age, gender, antiretroviral therapy and viral load. CONCLUSIONS The presence of X4-tropic viruses in HIV-2 infection is associated with low CD4+ cell counts, regardless of antiretroviral treatment. Along with CD4+ cell counts, viral tropism testing may assist decisions about when to initiate antiretroviral therapy in HIV-2-infected individuals.

Resistance to the most recent protease and non-nucleoside reverse transcriptase inhibitors across HIV-1 non-B subtypes

OBJECTIVES Limited data are available on resistance to etravirine, rilpivirine, darunavir and tipranavir in patients infected with HIV-1 non-B subtypes, in which natural polymorphisms at certain positions could influence the barrier and/or pathways to drug resistance. METHODS FASTA format sequences from the reverse transcriptase and protease genes recorded within the Spanish Drug Resistance database (ResRIS) were examined. RESULTS From 8272 genotypes derived from 5930 different HIV-1 patients included in ResRIS, 5276 genotypes had complete treatment information. Overall, 85% were from antiretroviral-experienced subjects and 7.5% belonged to HIV-1 non-B subtypes: CRF02_AG, C, F and G being the most prevalent variants. For etravirine, only G190A was more prevalent in B than non-B subtypes, whereas V90I and V179E were more frequent in non-B than B subtypes. For rilpivirine, V108I and Y188I were more frequent in B than non-B subtypes, whereas V90I was more prevalent in non-B subtypes. Despite these differences, the overall prevalence of resistance did not differ significantly when comparing etravirine or rilpivirine in B versus non-B subtypes (11.3% versus 7.4%, P = 0.13, and 10.5% versus 7.4%, P = 0.23, respectively). Despite more frequent natural polymorphisms in non-B than B subtypes at tipranavir resistance positions, the prevalence of tipranavir resistance was greater in B than non-B subtypes (11% versus 4.3%, P = 0.004), reflecting a greater antiretroviral exposure in the former. Darunavir resistance did not differ significantly when comparing B and non-B subtypes (5.8% versus 5.5%, P = 0.998). CONCLUSIONS The rate of resistance to the most recently approved protease and non-nucleoside reverse transcriptase inhibitors is low in antiretroviral-experienced patients, regardless of the HIV-1 subtype.