Ana Treviño

Hepatitis C therapy with HCV NS5B polymerase inhibitors

Introduction: Several HCV polymerase inhibitors are in advanced stages of clinical development. They are nucleos(t)ide and non-nucleoside analogs. Nucleos(t)ides inhibit viral replication acting as chain terminators whereas non-nucleosides block allosterically the HCV polymerase. Sofosbuvir is an uridine analog and currently the most promising HCV polymerase inhibitor, being active across all HCV genotypes. It has good tolerability and a robust barrier to resistance. In contrast, non-nucleoside analogs have low to moderate antiviral potency, a low barrier to resistance and inhibit only HCV genotype 1. Areas covered: Studies conducted with distinct HCV polymerase inhibitors as part of interferon-free combinations have opened a new landscape in which shorter treatment duration and all-oral regimens are envisioned as the future curative treatment for most chronic hepatitis C patients. Expert opinion: Antiviral drug development for HCV is progressing at a feverish pace. Amongst HCV polymerase inhibitors, sofosbuvir has positioned as unique companion with ribavirin as therapy for most HCV genotypes 2 or 3, and along with NS5A inhibitors for other HCV genotypes. Non-nucleoside HCV polymerase inhibitors are being developed only as part of all-oral combinations with protease inhibitors. The expected high cost of DAAs will preclude their prompt and wider use, allowing room for using alternative cheaper options in easier-to-treat patient populations.

Natural polymorphisms associated with resistance to new antivirals against HCV in newly diagnosed HIV-HCV-coinfected patients.

BACKGROUND Direct acting antivirals (DAA) targeting the HCV serine protease and RNA polymerase have recently entered clinical development. Information about primary resistance to these compounds in HIV-HCV-coinfected patients is scarce. METHODS All individuals newly diagnosed with HIV-1 at several clinics in Madrid between 2000 and 2010 were tested for serum HCV antibody and HCV RNA. The NS3 protease and NS5B polymerase genes were sequenced in all HCV viraemic patients with genotype 1 (G1). RESULTS From 1,684 individuals newly diagnosed with HIV-1 during the 10-year study period, 141 (8.4%) were positive for serum HCV RNA. Overall, 58% were infected with G1, being 1a in 64.2% of them. Altogether, 62% of G1a and 30% of G1b harboured HCV drug-resistant changes, with the most common being prQ80K (n=9), prV55A (n=2), polC316Y/N (n=3) and polV499A (n=24). Although no primary resistance mutations were identified for HCV protease inhibitors or nucleoside analogues, mutations C316Y/N and V499A conferring resistance to some non-nucleoside analogues were found in 6% and 51% of G1 patients, respectively. CONCLUSIONS Natural DAA resistance-associated mutations are frequently seen in HIV-HCV-coinfected individuals. Changes polV499A and prQ80K seem to be natural polymorphisms and their effect on treatment outcomes warrants further examination. However, drug resistance testing in HCV drug-naive individuals coinfected with HIV currently does not seem to be warranted before using HCV protease inhibitors and nucleoside analogues. More information is needed for HCV non-nucleoside analogues.

Trends in the prevalence and distribution of HTLV-1 and HTLV-2 infections in Spain

BackgroundAlthough most HTLV infections in Spain have been found in native intravenous drug users carrying HTLV-2, the large immigration flows from Latin America and Sub-Saharan Africa in recent years may have changed the prevalence and distribution of HTLV-1 and HTLV-2 infections, and hypothetically open the opportunity for introducing HTLV-3 or HTLV-4 in Spain. To assess the current seroprevalence of HTLV infection in Spain a national multicenter, cross-sectional, study was conducted in June 2009.ResultsA total of 6,460 consecutive outpatients attending 16 hospitals were examined. Overall, 12% were immigrants, and their main origin was Latin America (4.9%), Africa (3.6%) and other European countries (2.8%). Nine individuals were seroreactive for HTLV antibodies (overall prevalence, 0.14%). Evidence of HTLV-1 infection was confirmed by Western blot in 4 subjects (prevalence 0.06%) while HTLV-2 infection was found in 5 (prevalence 0.08%). Infection with HTLV types 1, 2, 3 and 4 was discarded by Western blot and specific PCR assays in another two specimens initially reactive in the enzyme immunoassay. All but one HTLV-1 cases were Latin-Americans while all persons with HTLV-2 infection were native Spaniards.ConclusionsThe overall prevalence of HTLV infections in Spain remains low, with no evidence of HTLV-3 or HTLV-4 infections so far.

Antiviral effect of raltegravir on HTLV-1 carriers

BACKGROUND In vitro studies support that integrase inhibitors, such as raltegravir, may inhibit human T cell lymphotropic virus type 1 (HTLV-1) replication. However, this hypothesis has not been tested in vivo. METHODS HTLV-1-infected individuals were invited to participate in a pilot, open study that examined whether 400 mg of raltegravir twice daily could exhibit any recognizable virological effect over 12 months. Proviral DNA was measured by a real-time PCR targeting the pol region. HTLV-1 integrase sequences were obtained from peripheral blood mononuclear cells (PBMCs) at baseline and during follow-up. RESULTS A total of five HTLV-1-infected individuals entered the study. All were infected with HTLV-1 subtype a. Two patients had HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), the rest being asymptomatic. The HTLV-1 proviral load was high in all cases (median 758 HTLV-1 DNA copies/10(4) PBMCs). Following the initiation of raltegravir therapy and for up to 6 months, both of the HAM/TSP patients experienced a transient decline in the HTLV-1 proviral load (2248 to 519 and 1033 to 861 copies/10(4) PBMCs, respectively), returning to baseline levels on subsequent determinations. No significant changes in the HTLV-1 proviral load were noticed in the three asymptomatic individuals (median proviral load of 755 copies/10(4) PBMCs over time). A total of 20 integrase sequences could be obtained from the five patients, and no genotypic substitutions were recognized comparing baseline and follow-up specimens under raltegravir. CONCLUSIONS Treatment with raltegravir in HTLV-1-infected individuals does not result in a significant reduction of proviral load beyond 6 months of therapy. The lack of continuous viral replication cycles in chronic HTLV-1 carriers most likely explains our findings.

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.

Development of Tropical Spastic Paraparesis in Human T-Lymphotropic Virus Type 1 Carriers Is Influenced by Interleukin 28B Gene Polymorphisms

Interleukin 28B (IL28B) rs12979860 polymorphisms were examined in 41 individuals with human T-lymphotrophic virus type 1 (HTLV-1). The alleles CT/TT were more frequent in 12 individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis than in 29 asymptomatic carriers (80% vs 20%; P = .03), and median HTLV-1 proviral load was greater in CT/TT than CC carriers (P = .01). Thus, IL28B testing and closer follow-up of HTLV-1 asymptomatic CT/TT carriers is warranted.

Spontaneous hepatitis C virus clearance in HIV patients with chronic hepatitis C bearing IL28B-CC alleles using antiretroviral therapy.

Background:A quarter of individuals acutely infected with hepatitis C virus (HCV) clear the virus spontaneously. Once chronic infection is established, HCV elimination generally can only be achieved using specific antiviral therapy, such as peg-interferon-ribavirin. Herein, we report a group of chronically HIV/HCV-coinfected patients that cleared HCV spontaneously while being treated only with antiretrovirals. Methods:Retrospective analysis of all HIV-infected individuals with positive HCV antibodies (HCV-Abs) and negative serum HCV-RNA seen during 2012 at a reference HIV clinic in Madrid. Results:From a total of 2366 HIV-infected individuals, 618 (26%) were HCV-Ab+, of whom 387 (62%) were positive for serum HCV-RNA. Individuals HCV-Ab+/HCV-RNA-negative were grouped into two categories – those that had eliminated HCV following a course of antiviral treatment (n = 198, 86%) and those who had cleared the virus spontaneously (n = 33, 14%). Eight with spontaneous clearance were HBsAg+ and might have cleared HCV as a result of viral interference. However, six (24%) out of the remaining 25 did so after being serum HCV-RNA+ for longer than 6 months (median 5.6 years, range 1.3–12 years). All harbored alleles and had undetectable plasma HIV-RNA on HAART around the time of HCV clearance. Conclusion:Spontaneous HCV clearance may occur in a subset of chronically HIV/HCV-coinfected patients on HAART harboring IL28B-CC. Given that antiretrovirals do not display any direct anti-HCV activity, recovery of innate immune responses could be responsible for these late HCV clearance episodes. Thus, periodic testing of serum HCV-RNA may be warranted in chronically HIV/HCV-coinfected patients on HAART harboring IL28B-CC alleles.

Hepatitis B, C, and D and HIV infections among immigrants from Equatorial Guinea living in Spain.

A total of 1,220 subjects from Equatorial Guinea living in Spain (median age = 41 years; 453 male and 767 female) was examined for antibodies to human immunodeficiency virus (HIV) and Hepatitis B (HBV), C (HCV), and D (HDV) viruses. Extracted RNA and DNA from the positive samples were used to quantify viral load. The prevalence of HIV antibodies, HCV RNA, and HBV surface antigen (HBsAg) was 10.8% (N = 132), 11.6% (N = 141), and 7.9% (N = 96), respectively. The most prevalent HIV variant was CRF02_AG (38.5%; N = 40). HCV genotype 4 (60%; N = 36) and HBV genotype A3 (32%; N = 8) were the hepatitis variants most frequently found. Superinfection with HDV was seen in 20.9% (N = 24) of HBsAg carriers. A control group of 276 immigrants from other sub-Saharan countries showed similar rates of HIV and HBsAg, although no HCV cases were found. Immigrants constitute a major source of HIV and hepatitis viruses in Spain; therefore, it is important that control measures are intensified.

HTLV infection among foreign pregnant women living in Spain

BACKGROUND The overall seroprevalence of HTLV infection among pregnant women in Spain is below 0.02% and accordingly universal antenatal screening is not recommended. However, as the number of immigrants has significantly increased during the last decade, this population might warrant specific considerations. OBJECTIVE To evaluate the seroprevalence of HTLV infection among immigrant pregnant women living in Spain. METHODS From January 2009 to December 2010 a cross-sectional study was carried out in all foreign pregnant women attended at 14 Spanish clinics. All were tested for HTLV antibodies using a commercial enzyme-immunoassay, being reactive samples confirmed by Western blot or PCR. RESULTS A total of 3337 foreign pregnant women were examined. Their origin was as follows: Latin America 1579 (47%), North Africa 507 (16%), East Europe 606 (18%), Sub-Saharan Africa 316 (9%), North America and West Europe 116 (3.5%) and Asia and Australia 163 (5%). A total of 7 samples were confirmed as HTLV positive, of which 6 were HTLV-1 and 1 HTLV-2. HTLV-1 infection was found in 5 women coming from Latin America and 1 from Morocco. The only woman with HTLV-2 came from Ghana. The overall HTLV seroprevalence was 0.2%, being 0.3% among Latin Americans and 0.2% among Africans. It was absent among women coming from other regions. CONCLUSIONS The seroprevalence of HTLV infection among foreign pregnant women in Spain is 0.2%, being all cases found in immigrants from Latin America and Africa. Given the benefit of preventing vertical transmission, antenatal screening should be recommended in pregnant women coming from these regions.

Changes in drug resistance patterns following the introduction of HIV type 1 non-B subtypes in Spain.

Natural genetic variability at the pol gene may account for differences in drug susceptibility and selection of resistance patterns across HIV-1 clades. Spread of non-B subtypes along with changes in antiretroviral drug use may have modified drug resistance patterns in recent years. All HIV-1 clinical samples sent to a reference laboratory located in Madrid for drug resistance testing since January 2000 were analyzed. The pol gene was sequenced and HIV-1 subtypes were assigned using the Stanford algorithm and phylogenetic analyses for non-B subtypes. Drug resistance mutations were recorded using the IAS-USA mutation list (April 2008). A total of 3034 specimens from 730 antiretroviral-naive individuals (92 with non-B subtypes) and 1569 antiretroviral-experienced patients (97 with non-B subtypes) were examined. The prevalence of HIV-1 non-B subtypes in the study period increased from 4.4% (2000-2003) to 10.1% (2004-2007) (p < 0.01). The most predominant variants were CRF02_AG (41.8%) and G (17.5%). Thymidine analogue mutations (TAMs) were more prevalent in B than non-B subtypes, in both drug-naive (6.2% vs. 1%; p < 0.01) and treatment-experienced patients (49% vs. 30%, p < 0.01). K103N was most frequent in B than non-B subtypes (34% vs. 21%; p < 0.01); conversely, 106A/M was more prevalent in non-B than B clades (11% vs. 5%). Codon 179 mutations associated with etravirine resistance were more frequent in non-B than B subtypes. Finally, secondary protease resistance mutations were more common in non-B than B clades, with a potentially significant impact at least on tipranavir. The prevalence of HIV-1 non-B subtypes has increased since the year 2000 in a large drug resistance database in Spain, determining changes in drug resistance patterns that may influence the susceptibility to new antiretroviral drugs and have an impact on genotypic drug resistance interpretation algorithms.