Safety and Immunogenicity of the GamTBvac, the Recombinant Subunit Tuberculosis Vaccine Candidate: A Phase II, Multi-Center, Double-Blind, Randomized, Placebo-Controlled Study.

GamTBvac is a candidate tuberculosis vaccine with two fusion proteins, containing Ag85a, ESAT6, CFP10, and a dextran-binding domain (DBD). Phase II of a double-blind, randomized, multicenter, placebo-controlled study in parallel groups in healthy adults to evaluate the safety and immunogenicity of GamTBvac in 180 previously-vaccinated with Bacillus Calmette-Guérin vaccine (BCG) healthy volunteers without Mycobacterium tuberculosis (MTB) infection was conducted. The dose (0.5 mL) of either the study drug or a placebo was administered subcutaneously twice with an 8-week interval. At eight timepoints from 14 to 150 days, whole blood and sera were assayed. Antigen-specific T-cell responses were measured by an in-house interferon-gamma release assay (IGRA-test), the QuantiFERON (QTF) test, and intracellular cytokine staining (ICS). For antibody response detection, the bead-based multiplex immunoassay (MIA) was applied. The vaccine confirmed an acceptable safety profile previously shown in a first-in-human clinical study. After stimulation with both fusions, the highest median level of INF-γ was detected on day 21. The GamTBvac vaccine induced antigen-specific interferon-gamma release, Th1 cytokine-expressing CD4+ T-cells, and IgG responses and results support further clinical testing of GamTBvac.

Streamlining the screening cascade for active Hepatitis C in Russia: A cost-effectiveness analysis.

OBJECTIVE: Screening for hepatitis C in Russia is a complex process that involves several visits and stepwise testing, limiting adherence and substantially reducing the yield in the identification of active infections. We aimed to evaluate the cost-effectiveness of different screening algorithms from a health system perspective. METHODS: A decision analytic model was applied to a hypothetical adult population eligible to participate in a general screening program for hepatitis C in Russia. The standard pathway (I: Screen for anti-HCV antibodies followed by a nucleic acid test for HCV RNA on antibody positives) was compared to three alternatives (II: Screen for antibodies, a reflexed test for HCV antigen on antibody positives, and RNA on antigen negatives; III: Screen for antibodies, a reflexed test for HCV antigen on antibody positives; IV: Screen for antigen). Each strategy considered a cascade of events (referral, adherence, testing, diagnosis) that must occur for screening to be effective. The primary measure of effectiveness was the number of diagnosed active infections. Calculations followed a health system perspective with costs derived from 2017 reimbursement rates and a willingness-to-pay of 2,000RUB ($82) per diagnosed active infection. Model was tested with deterministic and probabilistic sensitivity analyses. RESULTS: Non-adherence to screening stages reduced the capture rate of active infections in Strategy I from 79.0% to 40.6%. Strategies II, III, and IV were less affected and identified 69%, 67%, and 104% more infections. Average costs per diagnosed infection were decreased by 41% from 89,599RUB ($3,681) for I to 53,072RUB ($2,180), 53,004RUB ($2,177), and 59,633RUB ($2,450) for II, III, and IV, respectively. With a probability of 97%, Strategy III was most cost-effective with an incremental cost-effectiveness ratio vs. I of -1,373RUB (CI: -5,011RUB to -2,033RUB; $-56; CI: -$206 to -$84). Below a willingness-to-pay of 91,000RUB ($3,738), Strategy IV was not cost-effective. Sensitivity analyses confirmed the robustness of results. CONCLUSIONS: Testing strategies for hepatitis C with HCV antigen on HCV antibody positive cases offer a streamlining opportunity for population screening programs. Those shall increase the chances for detecting active infections and are cost-effective over current practice in Russia.

Sofosbuvir-based salvage therapy for HCV infection in cirrhotic patients with DAA failure and multidrug resistance.

Despite very high efficacies of direct-acting antivirals (DAAs) reported in clinical trials, treatment failure in real-life practice can occur in 5-10% of cases and is mostly associated with emergence of resistance-associated substitutions (RASs). Little is known about the efficacy of retreatment in these patients, especially in those with decompensated cirrhosis, and only a few retreatment studies have been performed so far. Here we present case reports of successful sofosbuvir-based treatment in patients with advanced class B cirrhosis with prior pegylated interferon/ribavirin and all-oral DAA failure with multiclass drug resistance. HCV resistance testing at failure was performed to guide the choice of salvage therapy.

Base-calling algorithm with vocabulary (BCV) method for analyzing population sequencing chromatograms.

Sanger sequencing is a common method of reading DNA sequences. It is less expensive than high-throughput methods, and it is appropriate for numerous applications including molecular diagnostics. However, sequencing mixtures of similar DNA of pathogens with this method is challenging. This is important because most clinical samples contain such mixtures, rather than pure single strains. The traditional solution is to sequence selected clones of PCR products, a complicated, time-consuming, and expensive procedure. Here, we propose the base-calling with vocabulary (BCV) method that computationally deciphers Sanger chromatograms obtained from mixed DNA samples. The inputs to the BCV algorithm are a chromatogram and a dictionary of sequences that are similar to those we expect to obtain. We apply the base-calling function on a test dataset of chromatograms without ambiguous positions, as well as one with 3-14% sequence degeneracy. Furthermore, we use BCV to assemble a consensus sequence for an HIV genome fragment in a sample containing a mixture of viral DNA variants and to determine the positions of the indels. Finally, we detect drug-resistant Mycobacterium tuberculosis strains carrying frameshift mutations mixed with wild-type bacteria in the pncA gene, and roughly characterize bacterial communities in clinical samples by direct 16S rRNA sequencing.

Hepatitis B-associated vasculitis in Alaska Natives: viral genotype, clinical and serologic outcome.

BACKGROUND: The highest incidence of hepatitis B virus (HBV)-associated vasculitis in the world has been reported in Alaska Natives. We examined the incidence of HBV-associated vasculitis before and after mass HBV vaccine immunization and the association between HBV genotype and vasculitis in a population-based cohort study in Alaska natives chronically infected with HBV. METHODS: Genotyping was performed in vasculitis cases and 644 hepatitis B-positive controls without vasculitis using polymerase chain reaction and sequencing of the S gene. Occurrence of HBV vasculitis from 1974 to 2004 was calculated. HBV vasculitis patients and controls were also tested for basal core promoter and precore mutations. RESULTS: Fifteen cases of HBV-associated vasculitis were identified: 13 (86%) had genotype D and one each genotype A and F. Genotype D was more commonly found in patients with vasculitis than controls [odd ratio (OR)=5.9, confidence interval (95% CI) 1.2, 21.8; P<0.015). CONCLUSIONS: HBV-associated vasculitis was associated with genotype D.

Hepatitis B virus genotypes in Alaska Native people with hepatocellular carcinoma: preponderance of genotype F.

BACKGROUND: The development of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B virus (HBV) infection has been associated with specific HBV genotypes and the presence of specific mutations. METHODS: From a cohort of Alaska Native people with chronic HBV infection, we genotyped 47 patients with HCC and 1129 patients without HCC, and we tested patients with HCC and control patients for mutations in the basal core promoter and precore regions. RESULTS: Genotype F was found in 68% of patients with HCC, versus 18% of those without HCC (P<.001). For patients with genotype F, the median age at diagnosis of HCC was lower than that for patients with other genotypes (22.5 vs. 60 years, respectively; P=.002). Overall, there were no significant differences in the number of basal core promoter and precore region mutations between patients with HCC and control patients. CONCLUSIONS: We found a significant association between genotype F and the development of HCC among Alaska Native people with chronic HBV infection but no significant association between HCC and basal core promoter or precore mutations in genotype F.

Kinetics of HBV DNA and HBsAg in acute hepatitis B patients with and without coinfection by other hepatitis viruses.

The kinetics of hepatitis B virus (HBV) and its surface antigen (HBsAg) during acute hepatitis has not yet been studied accurately in a representative number of patients. The influence of coinfecting hepatitis viruses during the acute phase of infection is not known. Three to four serum samples from 21 patients with acute HBV monoinfection and 27 with coinfection were taken at intervals of 6-10 days and analyzed for the number of HBV genome equivalents (ge) by real time polymerase chain reaction (PCR) and for HBsAg quantity using Laurell electrophoresis. Log HBV ge/ml decreased during the follow-up from 6.8 +/- 1.1 to 5.1 +/- 1.0 to 4.2 +/- 0.8 to 3.3 +/- 1.1 (mean +/- SD). The half-life times of HBV ge increased from 1.6 days at the beginning to 4 days at the end. HBsAg decreased much slower: from 38 to 23 to 12 to 3.8 microg/ml. Half-life time was around 8 days at the beginning and 5.7 days at the end, but 11 patients showed a rapid elimination of HBsAg and HBV DNA. Hepatitis C virus (HCV) coinfection did not change the kinetics of HBV ge and HBsAg significantly. A moderate but significant suppression of HBV ge levels was observed in hepatitis D virus (HDV) coinfected patients. HBsAg levels were, however, enhanced in this cohort. In conclusion, the data suggest that expression and elimination of HBV is in most patients with acute hepatitis B not altered by coinfecting hepatitis viruses. The initial decrease of HBV ge and HBsAg in serum appears to be caused by decay or non-specific removal in the absence of replacement.