Enhanced antiviral benefit of combination therapy with lamivudine and alpha interferon against WHV replication in chronic carrier woodchucks

Cell culture studies in our laboratory previously demonstrated synergistic antiviral activity for the combinations of lamivudine and a novel recombinant hybrid human alpha B/D interferon (rHu alpha B/D IFN) against hepatitis B virus (HBV) replication. Based on these results, a study was designed to determine if an enhanced antiviral effect with this drug combination could be demonstrated in vivo using the woodchuck hepatitis virus (WHV)/woodchuck experimental model of chronic HBV infection. Both antiviral agents have been shown to be effective against WHV replication in WHV chronic carriers during previous studies by our laboratories. Two combination treatment regimens were compared to matched monotherapies in a placebo-controlled trial. The first used simultaneous administration of rHu alpha B/D IFN and lamivudine for 24 weeks. The other combination treatment regimen used a staggered dosing schedule of 12 weeks of administration of lamivudine alone, followed by 12 weeks of simultaneous dosing with both drugs, followed by 12 weeks of therapy with rHu alpha B/D IFN alone. Both treatment regimens with combinations of lamivudine and rHu alpha B/D IFN were more effective at reducing WHV replication in chronically infected wood-chucks than the corresponding monotherapies. Both combination treatments produced antiviral effects that were at least equal to that expected for additive activity based on estimations generated by Bliss Independence calculations. The staggered treatment regimen reduced viraemia and intrahepatic WHV replication significantly more than that expected for additive interactions, indicating synergistic antiviral effects. These studies demonstrate that combination therapy of chronic WHV infection has enhanced antiviral benefit over corresponding monotherapies and indicate that combination treatment of chronic HBV infection can be superior to therapies using a single antiviral agent.     

Plaque inhibition assay for drug susceptibility testing of influenza viruses.

The relative antiviral activities of four drugs against contemporary strains of influenza A and B viruses were determined in Madin-Darby canine kidney cell monolayers with a plaque inhibition assay. This assay proved to be a reliable, rapid method of determining 50% inhibitory concentrations that correlated well with clinically achievable drug levels and the results of clinical trials. Contemporary strains of influenza A viruses (subtypes H1N1, H3N2, HSW1N1) required amantadine hydrochloride and rimantadine hydrochloride 50% inhibitory concentrations in the range of 0.2 to 0.4 microgram/ml, whereas 50% inhibitory concentrations ranged from approximately 50 to 100 micrograms/ml against influenza B viruses. Ribavirin was approximately 10-fold less active than amantadine hydrochloride against influenza A viruses, and the ribavirin 50% inhibitory concentrations against both influenza A and B viruses ranged from 2.6 to 6.8 micrograms/ml. Inosiplex had no antiviral activity in this test system.     

Clevudine therapy with vaccine inhibits progression of chronic hepatitis and delays onset of hepatocellular carcinoma in chronic woodchuck hepatitis virus infection

We examined a rational approach to therapy of chronic hepatitis B virus (HBV) infection that utilized the reduction of viral load combined with appropriately timed immune modulation/stimulation. In a placebo-controlled study, chronic woodchuck hepatitis virus (WHV) carrier woodchucks received clevudine (L-FMAU), previously shown to have especially potent and sustained antiviral activity in woodchucks, for 32 weeks followed by WHV surface antigen (WHsAg) alum-adjuvanted vaccine at 32, 36, 40 and 48 weeks. Clevudine induced significant reductions in viraemia, surface antigenaemia, hepatic WHV nucleic acids, and hepatic core and surface antigens. Viral replication markers remained markedly suppressed in 75% of the clevudine-treated woodchucks following drug withdrawal, but remained at high levels in the vaccine monotherapy and placebo groups. Combination drug and vaccine therapy had benefits based on sustained reduction of viraemia, antigenaemia, and hepatic WHV DNA and RNA; inhibition of progression of chronic hepatitis; reduced frequency of chronic liver injury; and delayed onset of hepatocellular carcinoma (HCC). Combination therapy contributed to prevention of HCC in up to 38% of treated carriers, although the growth rate of established HCC was not affected. This study demonstrates enhanced benefits of combination chemo-immunotherapy against viral load and disease progression in chronic hepadnaviral infection, and provides a platform for further development of such treatment regimens.     

The pharmacology of a new pasteurized antihemophilic factor concentrate derived from human blood plasma

The pharmacology of a new pasteurized factor VIII (FVIII) concentrate derived from human blood plasma was studied in 23 adults with hemophilia A. In Part 1 of the study involving six nonbleeding subjects, the mean increase in FVIII activity was 1.43 +/- 0.34 U per ml 10 minutes after an intravenous dose of 50 U per kg. The intravascular survival kinetics in these six patients showed a biphasic decay curve with an initial mean half-life of 5.1 +/- 1.2 hours probably representing early redistribution, and a late half-life of 13.3 +/- 4.9 hours. In Part 2 of the study, the activity at 10 minutes was measured in another 17 patients, as well as in one patient already studied in Part 1. The mean increase in activity with the 24 observations was 1.13 +/- 0.37 U per ml with a mean FVIII dosage of 51.0 +/- 2.6 U per kg of body weight. Only one patient had an allergic reaction, which did not recur when the patient was given a second lot.     

The 6-min walk distance: change over time and value as a predictor of survival in severe COPD.

The 6-min walk distance (6MWD) is used to evaluate the functional capacity of patients with chronic obstructive pulmonary disease (COPD). The change in 6MWD over time and its correlation with changes in spirometry and survival are unclear. Patients (n=198) with severe COPD and 41 age-matched controls were followed for 2 yrs, and anthropometrics, spirometry, 6MWD and comorbidities were measured. The 6MWD decreased in the COPD group from 238 +/- 107 m to 218 +/- 112 m (-26 +/- 37 m x yr(-1)), and increased in the control group from 532 +/- 82 m to 549 +/- 86 m (12 +/- 25 m x yr(-1)). In both groups, there was a poor correlation with changes in forced expiratory volume in one second (FEV1). Nonsurvivors in the COPD group (42%) had a more pronounced change in the 6MWD (-40 versus -22 m x yr(-1)) but a similar change in FEV1 (118 versus 102 mL x yr(-1)). The 6MWD independently predicted survival, after accounting for age, body mass index, FEV1 and comorbidities. In severe chronic obstructive pulmonary disease, the 6-min walk distance predicts mortality better than other traditional markers of disease severity. Its measurement is useful in the comprehensive evaluation of patients with severe disease.     

Predicting Recurrence and Progression of Noninvasive Papillary Bladder Cancer at Initial Presentation Based on Quantitative Gene Expression Profiles

Background

Currently, tumor grade is the best predictor of outcome at first presentation of noninvasive papillary (Ta) bladder cancer. However, reliable predictors of Ta tumor recurrence and progression for individual patients, which could optimize treatment and follow-up schedules based on specific tumor biology, are yet to be identified.

Objective

To identify genes predictive for recurrence and progression in Ta bladder cancer at first presentation using a quantitative, pathway-specific approach.

Design, setting, and participants

Retrospective study of patients with Ta G2/3 bladder tumors at initial presentation with three distinct clinical outcomes: absence of recurrence (n = 16), recurrence without progression (n = 16), and progression to carcinoma in situ or invasive disease (n = 16).

Measurements

Expressions of 24 genes that feature in relevant pathways that are deregulated in bladder cancer were quantified by real-time polymerase chain reaction on tumor biopsies from the patients at initial presentation.

Results and limitations

CCND3 (p = 0.003) and HRAS (p = 0.01) were predictive for recurrence by univariate analysis. In a multivariable model based on CCND3 expression, sensitivity and specificity for recurrence were 97% and 63%, respectively. HRAS (p < 0.001), E2F1 (p = 0.017), BIRC5/Survivin (p = 0.038), and VEGFR2 (p = 0.047) were predictive for progression by univariate analysis. Multivariable analysis based on HRAS, VEGFR2, and VEGF identified progression with 81% sensitivity and 94% specificity. Since this is a small retrospective study using medium-throughput profiling, larger confirmatory studies are needed.

Conclusions

Gene expression profiling across relevant cancer pathways appears to be a promising approach for Ta bladder tumor outcome prediction at initial diagnosis. These results could help differentiate between patients who need aggressive versus expectant management.