Antiviral Therapy

Human adenoviral (HAdV) infections are usually mild and self-limited, however, some infections from species A, B, C, D and E, can cause severe illnesses, which have raised public health concerns over the past few years. Current available antiviral therapies have limited efficacy and severe toxicity; therefore, finding new targets for specific anti-adenoviral drug design is urgently needed. Our previous work showed that the small molecule compound, HBX, inhibits HAdV type 5 (species C, HAdV-C5) replication and oncogenic transformation through inhibition of the cellular pro-viral factor ubiquitin-specific protease 7 (USP7). Here, we have tested the ability of HBX to inhibit other HAdV species, as well as different clinical isolates that are the cause of severe infections.

We treated HAdV-infected A549 cells with different concentrations of HBX and analysed the antiviral efficacy of the drug by determining the half maximal inhibitory concentration (IC₅₀) necessary to decrease both viral genome copies and virus progeny production at different time points after infection.

In addition to its effect on HAdV-C5, HBX was able to significantly inhibit virus genome replication and progeny release of all adenovirus types tested, with the exception of types 12 and 31, from species A. Of note, clinical isolates were more sensitive to HBX treatment than their prototype strains.

These results point to HBX as a promising broad-spectrum anti-adenoviral drug, opening new opportunities to prevent severe adenoviral infections and to improve their treatment.

HCV infections can now be completely cured, thanks to the currently marketed direct-acting antivirals (DAAs). It is known that HCV patients carry viral populations with baseline polymorphisms and/or mutations that make them resistant against some of these DAAs, which can negatively impact the patient's treatment outcome. Using complete HCV coding sequences isolated from 1,306 treatment-naive patients of genotypes (GTs) 1, 2, 3, 4 and 6 from around the globe, we studied the prevalence of baseline resistance-associated polymorphisms (RAPs) and resistance mutations (RMs) against DAAs that are currently on the market or in clinical trials.

The HCV genome sequences used in this study were retrieved from the NCBI database. RAPs and RMs, with reference to HCV GT1a, were identified using the HCV Geno2pheno web server.

Nearly 50% of the total amino acid positions (including NS3 protease, NS5A and NS5B) studied are baseline polymorphisms that differentiated one GT from the rest. A proportion of these baseline polymorphisms and baseline non-polymorphic RMs could confer a significant increase in resistance against DAAs.

In this study, we show the presence and prevalence of RAPs and RMs in DAA treatment-naive patients against currently used DAAs or DAAs in clinical trials. Our study suggests that RAPs and RMs profiling of HCV patients should be performed before the start of the therapy. Our results should be relevant especially in low- and middle-income countries, where the patients have a large variation of GTs and subtypes, and where the generic HCV treatment is now increasingly available.

Raltegravir (RTG) and dolutegravir (DTG) have different pharmacokinetic patterns in the gastrointestinal tract. To determine if this results in pharmacodynamic differences, we compared HIV RNA, HIV DNA and immunological markers in gut-associated lymphoid tissue (GALT) of HIV-infected participants receiving RTG or DTG with tenofovir+emtricitabine (TDF/FTC).

GALT specimens from the terminal ileum, splenic flexure and rectum were obtained by colonoscopy at a single time point in 20 adults treated with RTG (n=10) or DTG (n=10) with HIV RNA <50 copies/ml. Flow cytometry, drug concentrations, and HIV RNA and DNA were analysed in tissue. CD4/8⁺ T-cells were tested for γδ TCR, and markers of T-cell activation and exhaustion. Data are reported as median (Q1–Q3).

A total of 15 men and 5 women were enrolled. There was no difference in time since HIV diagnosis for those on RTG (9.5 [4–22] years) and DTG (17 [1–24] years; P=0.6), although time on RTG (5.4 [2.3–6.7] years) was greater than DTG (1.0 [0.1–1.5] years; P<0.001). Concentrations of RTG and DTG in rectal tissue were similar to previous reports: median tissue:plasma ratio was 11.25 for RTG and 0.44 for DTG. RNA:DNA ratios were 1.14 (0.18–5.10) for the RTG group and 0.90 (0.30–18.87) for the DTG group (P=0.95). No differences (P≥0.1) between CD4⁺ and CD8⁺ T-cell markers were found.

RTG produced higher tissue exposures than DTG, but no significant differences in GALT HIV RNA, DNA or most immunological markers were observed. ClinicalTrials.gov NCT02218320.

Cytomegalovirus (CMV) infection is a major risk factor for mortality in infants with severe combined immunodeficiency (SCID) and other profound immune defects. Specific antiviral therapy must be initiated early and aggressively because of the potential for antiviral resistance, rapid dissemination and poor transplant outcomes. Combination antiviral therapy is routinely administered for some viral infections, but the value of this approach for the treatment of CMV is unclear. Here we explore a strategy of initial combination therapy for high-risk infants with CMV infection.

We reviewed medical records of infants ≤6 months of age hospitalized between 2007–2015 who received ganciclovir (GCV) or foscarnet (FOS) monotherapy or initial combination GCV + FOS for CMV disease. The combination therapy group consisted of severely immunocompromised infants being considered for haematopoietic cell transplantation (HCT).

Four patients received initial combination antiviral therapy and 26 patients received initial monotherapy during the study period. Combination antiviral recipients demonstrated initial improvement in viraemia and two of three who continued with this therapy survived the infection. Clinically significant resistance mutations did not emerge. Toxicity was common; neutropenia, thrombocy-topenia and electrolyte abnormalities were the most frequent adverse events in both groups. Creatinine elevation was uncommon in both groups.

Combination GCV + FOS therapy may be a safe alternative to monotherapy in high-risk infants, especially those who are pre-transplant with primary immune deficiency syndromes and high viral loads.

Although the efficacy of combination therapy with lamivudine or tenofovir and pegylated interferon (PEG-IFN) has been reported in patients with chronic hepatitis B (CHB), the long-term effect of the combination based on the observation of clinical course remains to be clarified. We previously reported the efficacy of combination therapy with entecavir (ETV) and PEG-IFN. Here, we investigated the long-term effect of this combination in patients with CHB.

We administered both ETV and PEG-IFN-α2a or -2b simultaneously to 26 patients with HBV genotype C infection. Treatment was continued for 48 weeks followed by 24 weeks of observation period; we examined the virological and biochemical responses. We also analysed characteristics related to the post-treatment relapse. Finally, we investigated the long-term therapeutic effects.

Average reduction of intra-hepatic cccDNA level was 1.2 log copies/μg at the completion of administration. Pretreatment hepatitis B surface antigen (HBsAg) level with more than 3.5 log U/ml was identified as a predictive factor for relapse. Furthermore, the cumulative rates of HBsAg-negative patients at 1, 3 and 5 years after the completion of administration were 3.8, 8.4 and 15%, respectively (mean follow-up period: 4.8 years).

Baseline HBsAg level with more than 3.5 log U/ml is a useful predictor for relapse 24 weeks after the completion of administration in patients treated with combination therapy. Combination with ETV and PEG-IFN could be an option for treatment of CHB patients especially in those with baseline HBsAg levels of less than 3.5 log U/ml.

Community respiratory viruses (CRVs) are associated with upper respiratory viral infections (URI), pneumonia or life-threatening respiratory disease in patients with allogeneic haematopoietic stem cell transplantation (allo-HSCT). Our aim is to demonstrate our URI experience related to CRVs after allo-HSCT.

From January 2013 to November 2015, 39 post allo-HSCT patients with acute URI symptoms were included in the study. We evaluated CRVs by multiplex PCR from nasopharyngeal wash and throat swabs.

The median age of the patients was 39 (range 20–67 years). A total of 25 patients (64%) had viral panel positivity at a median 140 days post-transplant (range 3–617 days). The most common agents detected were respiratory syncytial virus (32%) and parainfluenza (32%). The patients with viral panel positivity had significantly lower lymphocyte count (1.05x10⁹/l versus 3.09x10⁹/l; P=0.013). During follow-up, 20 patients (80%) were diagnosed with pneumonia. Patients with concurrent bacterial or fungal infections were more likely to have pneumonia (100% versus 68%; P=0.023). 10 patients (40%) died due to pneumonia and related complications. Lower lymphocyte counts and higher C-reactive protein levels at the time of viral panel positivity were risk factors for mortality (1.5x10⁹/l versus 0.39x10⁹/l, P=0.007; 74.2 versus 199.7, P=0.006).

The viral panel was positive in 64% of patients with acute URI symptoms. Lower lymphocyte count was detected in CRV-positive patients. The onset of concomitant bacterial or fungal infections increased the risk of lower respiratory infection disease. Indeed, prospective studies should be designed for risks and outcomes of CRVs in allo-HSCT recipients.

Loss to follow-up (LTFU) is a crucial indicator to evaluate the effectiveness of HIV care and treatment programmes. We assessed the LTFU rate and associated factors of Thai HIV-infected patients who enrolled in the National AIDS Program (NAP) for two periods: prior to (pre-ART) and after starting ART (ART-patients).

Thai HIV patients aged ≥15 years enrolled in NAP from 2008 to 2014. Vital status was ascertained by linkage with the National Death Registry. Competing risk models were used to calculate the adjusted sub-distribution hazards (aSHR) for LTFU for pre-ART and ART-patients, with death considered as a competing risk.

A total of 157,026 patients registered in care and were included in analyses. The cumulative incidence of LTFU in pre-ART patients at 1 year was 10.2%, whereas in ART-patients it was 12.8%. Among pre-ART patients, younger age (<30 versus ≥45 years, aSHR 1.60, 95% CI 1.49, 1.72), less advanced HIV stage (aSHR 1.29, 95% CI 1.21, 1.37) and higher CD4⁺ T-cell count (≥350 versus <100, aSHR 6.31, 95% CI 5.74, 6.95) had a higher chance of LTFU. ART-patients with high baseline CD4⁺ T-cell count (CD4 ≥350 versus CD4 <50, aSHR 2.06, 95% CI 1.97, 2.15) and non-advanced HIV stage had increased risk of LTFU.

Our findings provide new evidence of the LTFU rate in Thai HIV-infected patients in NAP. Emphasis needs to be placed on improving follow-up in all patients with higher CD4⁺ T-cell counts. LTFU will be important to monitor as programmes move to commence ART regardless of CD4⁺ T-cell count.

Hepatitis B reactivation in patients with resolved HBV can occur during hepatitis C treatment with direct-acting antivirals, but only a few cases have been described. It is not clear which patients are at risk for HBV reactivation and how to manage them.

Three patients (all hepatitis B surface antigen [HBsAg]-negative, antibody to hepatitis B core [anti-HBc] positive and HBV DNA negative) experienced a late HBV reactivation 12 weeks post-treatment but were able to control their viraemia. HCV RNA, HBV DNA, anti-HBc and anti-HBs were measured in these patients and in 37 HBsAg-negative, anti-HBc positive, HBV DNA negative control patients during direct-acting antiviral therapy for chronic hepatitis C.

Baseline anti-HBs do not differ between patients with and without HBV reactivation. Patients with HBV reactivation, however, significantly increased their anti-HBs at time of reactivation, while patients without HBV reactivation show stable anti-HBs during therapy (P=0.007).

Anti-HBs might be an important marker to delineate patients at risk for clinically significant HBV reactivation.

The novel available interferon (IFN)-free regimens significantly improved the sustained virological response (SVR) in patients with chronic hepatitis C (CHC), without important side effects and with shorter duration of treatment. In a subset of patients, however, the treatment failure (TF) was due to the presence of resistance-associated substitutions (RAS) that lead to virological breakthrough (BT) or relapse. We analysed in this case series the role of RAS on the TF in cirrhotic patients with genotype (GT)4, treated with a previous IFN-free regimen, and retreated with the combination of sofosbuvir (SOF)/velpatasvir (VEL) for 12 or 24 weeks, without ribavirin (RBV).

We included in this analysis all patients with GT4 who failed a previous IFN-free treatment, with the presence of RAS at BT or relapse. All patients were retreated with a fixed combination of SOF/VEL for 12/24 weeks, without RBV. We evaluated the SVR and the MELD score change after the treatment.

Seven patients were described. All were cirrhotic, Child–Pugh A (n=5), B (n=2); baseline RAS were detected in 4/7 subjects; at post-treatment detection, NS5 RAS were: F28S (n=1), Q30K (n=2), S30G (n=1), NS3 were: S122R (n=1), S122G (n=2), D168V (n=3). All retreated patients gained SVR. MELD score improved in all subjects with a median change of 3 points. No significant side effects or adverse events were reported.

The combination SOF/VEL could be considered for the retreatment of cirrhotic GT4 patients who failed a previous IFN-free treatment with the presence of RAS in NS3 or NS5 regions.