Arenaviruses: inhibition by amantadine hydrochloride

Evaluation of amantadine in chronic hepatitis C: a meta-analysis

BACKGROUND/AIMS

The benefit of amantadine combination therapy, either with interferon (IFN) alone (double therapy) or with ribavirin and IFN (triple therapy) is unknown.

METHODS

We analyzed the effect of amantadine on the end-of-treatment virological response and the sustained response using meta-analysis of 31 randomized controlled trials.

RESULTS

Overall analysis revealed a significant effect of amantadine. Triple therapy was the best regimen for improving the sustained response (mean difference: 8.4%, 95% CI: 2.4-13.8%, P=0.002). In subgroup analysis, amantadine did not have a significant effect upon naive patients or relapsers. In non-responders, combination therapy with amantadine was associated with a significant effect on the sustained response (mean difference: 8.3%, 95% CI: 1.9-14.6%, P=0.01). In sensitivity analysis, double therapy did not improve virological responses. Conversely, triple therapy tended to improve the end-of-treatment virological response and was associated with a significant effect upon the sustained response (mean difference: 12.7%, 95% CI: 3.8-21.6%, P=0.005).

CONCLUSIONS

Combination therapy with amantadine is of no effect upon naive patients or relapsers. In non-responders, triple therapy with amantadine improved the sustained response. New randomized controlled trials are required to confirm this meta-analysis.

Triple therapy with amantadine in treatment-naive patients with chronic hepatitis C: a placebo-controlled trial

The antiviral efficacy of amantadine in patients with chronic hepatitis C is controversial. In this randomized, prospective, placebo-controlled, multicenter trial, triple therapy with interferon alfa (IFN-alpha)-2a plus ribavirin and amantadine (amantadine group) was compared with combination therapy IFN-alpha plus ribavirin (control group). Four hundred previously untreated patients with histologically proven chronic hepatitis C were randomly allocated to treatment with amantadine sulphate (100 mg twice daily orally) or a matched placebo together with IFN-alpha induction plus ribavirin (1,000-1,200 mg/day orally) for 48 weeks. The primary end point was sustained virologic response (SVR) defined as undetectable serum hepatitis C virus (HCV) RNA (<100 copies/mL) 24 weeks after the end of treatment. SVR was observed in 52% of the amantadine group and in 43.5% of the control group (P =.11). Among patients with HCV genotype 1 infection, the corresponding SVR rates were 39% and 31%, respectively. The virologic on-treatment response rate in week 24 was significantly higher in the amantadine group as compared with the control group (70% vs. 59%, respectively, P =.016). This beneficial effect was mainly related to HCV type 1-infected patients (63% vs. 47%, respectively, P =.012). Independent factors associated with SVR, according to multiple logistic regression analysis, were amantadine treatment, low baseline HCV RNA, platelet counts (>/=250/nL), pretreatment ALT quotient >/=3, and GGT level (<28 U/L) as well as HCV genotypes other than 1. In conclusion, although we could not demonstrate a significant advantage of the triple regimen in univariate analysis, multivariate analysis offers arguments that amantadine should be considered as a potential anti-HCV drug in future studies.

Interferon and amantadine in naive chronic hepatitis C: a double-blind, randomized, placebo-controlled trial

Recent controlled trials on the efficacy of an amantadine/interferon combination in treatment-naive patients with chronic hepatitis C yielded contradictory results. We therefore conducted a large, double-blind, placebo-controlled, multicenter trial in naive patients with chronic hepatitis C: 246 patients were randomized to receive interferon alfa-2a (6 MIU sc thrice weekly for 20 weeks, then 3 MIU sc thrice weekly) and either amantadine sulphate (2 x 100 mg p.o. QD) or placebo. Treatment continued for a total of 52 weeks, if HCV-RNA in serum polymerase chain reaction (PCR) had fallen below detection limit (1,000 copies/mL) at treatment week 10, and stopped otherwise. All patients were followed for 24 weeks off therapy. After 10 weeks of treatment, 66/121 patients treated with amantadine (55%) and 78/125 treated with placebo (62%) had lost HCV-RNA (n.s.). After 24 weeks of follow-up, 25 patients in the amantadine (21%) and 17 (14%) in the placebo group remained HCV-RNA negative (n.s.). During therapy, virologic breakthroughs occurred less often in the amantadine than in the placebo group [14 (12%) vs. 27 (22%) patients; P =.04]. Multivariate logistic regression analysis revealed genotype, viremia level, age, and amantadine therapy [risk ratio 0.4 (95%CI 0.2-1.0), P =.05] as predictors of sustained virologic response. Adverse events and impact of therapy on quality of life were similar in amantadine and placebo treated patients. Compared with current standard treatment (interferon/ribavirin), the interferon/amantadine combination was not cost-effective. In conclusion, amantadine does not add to a clinically relevant extent to the treatment of naive patients with chronic hepatitis C.

Randomized, placebo-controlled, double-blind trial with interferon-alpha with and without amantadine sulphate in primary interferon-alpha nonresponders with chronic hepatitis C

In primary interferon-alpha (IFN-alpha) nonresponders with chronic hepatitis C, retreatment with IFN-alpha has only limited efficacy with sustained response rates below 10%. Therefore, the aims of the present study were to compare the efficacy and safety of IFN-alpha alone or in combination with amantadine sulphate in nonresponders to previous IFN-alpha monotherapy. Fifty-five IFN-alpha nonresponders with chronic hepatitis C (mean age: 46.6 years) received IFN-alpha 6 MIU thrice weekly for 24 weeks followed by 3 MIU thrice weekly for additional 24 weeks. Amantadine sulphate (n=26) or a matched placebo (n=29) was given orally twice daily for 48 weeks. Because of a low initial response rate at week 12 (13/55 patients) and a high breakthrough rate (8/13 patients) after IFN-alpha dose reduction in week 24, a virological end-of-treatment response with undetectable serum HCV-RNA (< 1000 copies/mL) was achieved in only five patients (IFN-alpha/amantadine sulphate, one patient; IFN-alpha/placebo, four patients). After 24 weeks follow-up a sustained virological response was observed in only two patients receiving IFN-alpha and placebo. Health-related quality-of-life analysis showed a substantial improvement of the Profile of Mood States (POMS) scale concerning the subscales fatigue (P < 0.05) and vigor (P < 0.05) in patients receiving combined IFN-alpha/amantadine sulphate treatment compared with those treated with IFN-alpha alone. IFN-alpha/amantadine sulphate combination therapy was well tolerated without any serious adverse events. In conclusion, retreatment with IFN-alpha and amantadine sulphate does not increase the low sustained virological response rates of IFN-alpha therapy in primary IFN-alpha nonresponders with chronic hepatitis C, but may lead to a sustained improvement of health-related quality-of-life.

Randomized, double-blind, placebo-controlled trial of interferon alfa2a with and without amantadine as initial treatment for chronic hepatitis C

Although the antiviral effects of amantadine sulphate (1-aminoadamantan sulphate) have not been characterized for the hepatitis C virus (HCV), previous pilot studies have suggested promising results in patients with chronic hepatitis C. The aim of the present study was to compare the efficacy, safety, and health-related quality of life (HRQOL) of interferon alfa (IFN-alpha) alone or in combination with oral amantadine for treatment of chronic hepatitis C. One hundred nineteen previously untreated patients with chronic hepatitis C were randomly allocated to treatment with IFN-alpha2a at a dose of 6 megaunits 3 times a week subcutaneously for 24 weeks, followed by 3 megaunits thrice weekly for an additional 24 weeks plus amantadine sulphate administered orally 100 mg twice a day for 48 weeks or the same IFN regimen plus a matched placebo. The primary endpoint was undectable serum HCV RNA (<1,000 copies/mL) at week 24 after treatment. At the end of treatment and the 24-week follow-up period serum HCV RNA was undetectable in 20 (34%) and 6 (10%) of the 59 patients treated with the combination IFN-alpha plus amantadine and in 20 (33%) and 13 (22%) of the 60 patients treated with IFN-alpha alone, respectively (P = n.s.). Discontinuation of therapy for adverse events was similar in both treatment groups. Although treatment with IFN-alpha worsened HRQOL, combination with amantadine showed a substantial trend to improve fatigue and vigor. In conclusion, combination therapy IFN-alpha plus amantadine is as effective as IFN-alpha monotherapy in previously untreated patients with chronic hepatitis C.

In vitro effect of amantadine and interferon alpha-2a on hepatitis C virus markers in cultured peripheral blood mononuclear cells from hepatitis C virus-infected patients

The effects of amantadine (1-5 microM) and interferon alpha (IFNalpha)-2a alone (1000 IU/ml) and combined, have been studied in cultured peripheral blood mononuclear cells (PBMC) from 15 chronic hepatitis C patients and ten healthy donors. Amantadine itself did not affect cell viability and had minor effects on the response to mitogens by PBMC. Four patients (27%), but no donors, had hepatitis C virus (HCV) core and NS3-specific proliferative responses. Amantadine suppressed these responses in all cases and its antiproliferative effect was greater than that of IFNalpha (Mann-Whitney's U-test: P < 0.05 in both cases). All PBMC cultures from patients, but none from donors, were HCV RNA positive. Amantadine alone or combined with IFNalpha dose-dependently reduced HCV RNA content in individual PBMC (Wilcoxon's signed rank test: 1 microM, P < 0.05; 2 microM, P < 0.02; and 5 microM, P = 0.16) with respect to untreated cultures. In addition, 7, 13 and 20% of PBMC cultures became HCV RNA negative with 2 microM amantadine alone, IFNalpha alone and their combination, respectively. Finally, in contrast to IFNalpha, amantadine did not modify expression of 2',5'-oligoadenylate synthetase activity or the spontaneous or mitogen-stimulated IFNgamma and interleukin 10 production. In conclusion, these effects in PBMC from HCV patients suggest that the amantadine/IFNalpha combination might be considered a therapeutic option for treating chronic hepatitis C patients.

Uses of antibiotics in plant pathology and production

The dihydrochloride salt of (S,S)-1,2-bis(5-methoxy-2-benzimidazolyl)-1,2-ethandiol (A37536) inhibits the synthesis of lymphocytic choriomeningitis (LCM), Parana, and Pichinde viruses in L-929 cells. The compound has no direct inactivating effect on LCM virus nor does it affect the adsorption of LCM virus to L cells. The drug-cell interaction is slow. Maximal activity is observed only by exposing cells to the drug at least 8 h prior to LCM virus infection, or by concomitant drug treatment and infection at a low multiplicity. Addition of serum-free media to L cells after LCM virus infection diminishes the activity of A37536. Whereas A37536 exhibits its antiviral activity at concentrations that have little or no effect on L cell division rate, a marked change can be noted in the cell's sensitivity to lysis by standard trypsin dispersal procedures. A37536 has no specific antiviral activity in LCM virus-infected BHK, HeLa, or Vero cells. All of the four tested derivatives of A37536 showed antiviral activity against LCM virus but only at concentrations that reduced the growth rate or were toxic to L cells.

Arenaviruses: cellular response to long-term in vitro infection with parana and lymphocytic choriomeningitis viruses

Persistent infections were established in suspension cultures of BHK21/13S cells with both Parana and lymphocytic choriomeningitis viruses. Four generations after infection with either virus, more than 90% of the cells scored as infective centers, with concomitant peaks in extracellular virus yields. In both cultures the synthesis of detectable plaque-forming units (PFU) ceased about the 50th generation postinfection, and this condition was maintained until the 350th cell generation when the cultures were discontinued. The generation time of each culture was identical to that of uninfected parent controls, and at no time were cytopathic effects evident. In spite of the absence of infectivity, over 90% of the cells sampled at various times contained viral antigen demonstrable by immunofluorescence. When either of these persistently infected cell lines was substituted for normal cells in the standard plaque assay, very low efficiencies of plating were observed for homotypic and heterotypic viruses. Plaque formation by several heterologous viruses was virtually unaffected. The mechanism of homotypic plaque exclusion in both cell lines was shown to occur beyond the virion adsorption stage. The original infecting virus genome persisted in both cell lines after standard virus was no longer detectable. This was shown with the lymphocytic choriomeningitis virus-infected cells after storage in liquid nitrogen. After thawing, such cells were found to synthesize standard virus for a brief period. Although the Parana virus-infected cells did not behave this way, the growth medium from these cells would initiate PFU synthesis in normal cells within 36 hr after infection.