Treatment of chronic hepatitis C with amantadine hydrochloride in patients who had not responded to previous treatment with interferon-alpha and/or ribavirin

Review article: management of chronic hepatitis C in patients with contraindications to anti-viral therapy

BACKGROUND

There are patients with chronic hepatitis C who are not eligible for the current interferon-based therapies or refuse to be treated due to secondary effects.

AIM

To provide information on alternative treatments for the management of these patients.

METHODS

A PubMed search was performed to identify relevant literature. Search terms included hepatitis C virus, anti-inflammatory treatment, antioxidant, natural products and alternative treatment, alone or in combination. Additional publications were identified using the references cited by primary and review articles.

RESULTS

Several approaches, such as iron depletion (phlebotomy), treatment with ursodeoxycholic acid or glycyrrhizin, have anti-inflammatory and/or anti-fibrotic effects. Life interventions like weight loss, exercise and coffee consumption are associated with a biochemical improvement. Other alternatives (ribavirin monotherapy, amantadine, silibinin, vitamin supplementation, etc.) do not have any beneficial effect or need to be tested in larger clinical studies.

CONCLUSION

There are therapeutic strategies and lifestyle interventions that can be used to improve liver damage in patients with chronic hepatitis C who cannot receive or refuse interferon-based treatments.

Induction doses of interferon-alpha-2a in combination with ribavirin and/or amantadine for the treatment of chronic hepatitis C in non-responders to interferon monotherapy: a randomized trial

The benefit of the triple therapy (interferon + amantadine + ribavirim) is still unknown. The efficacy of induction doses of interferon-alpha-2a monotherapy or in combination with ribavirin and/or amantadine was evaluated in interferon non-responders with chronic hepatitis C. A total of 378 patients were randomized. All the groups received the same doses and duration of interferon-alpha-2a: (i) interferon 9 MUI/day for 4 weeks and then 3 MUI/3 t.i.w. for 44 weeks (n = 53); (ii) interferon in combination with amantadine 100 mg twice daily for 48 weeks (n = 111); (iii) interferon in combination with ribavirin 1000-1200 mg (n = 106); (iv) interferon in combination with amantadine and ribavirin (n = 108). Baseline parameters were similar in the four groups. Sustained virological and biochemical responses were 13%, 6%, 18% and 22% respectively. No significant differences were found between double ribavirin arm vs triple therapy, but the difference was significant between interferon-amantadine (P = 0.008) and triple therapy (P = 0.0005). Hence, the induction doses of interferon in combination with ribavirin or ribavirin plus amantadine showed encouraging results in patients with chronic hepatitis C who were resistant to interferon. However, triple therapy is not superior to double.

Amantadine in treatment of chronic hepatitis C virus infection?

SUMMARY

Treatment of chronic hepatitis C (CHC) continues to be an important and growing challenge. As the response rate to FDA-approved treatment improved over the past decade, we are facing increasing number of difficult-to-treat patients such as those who have failed prior anti-viral therapy. The role of amantadine in the treatment of CHC remains unclear. Studies thus far have produced conflicting results, and type II error could not be excluded. This review summarized results published in the literature from 1997 to 2003, and reviewed the existing questions and controversies regarding the use of amantadine. Current literature suggests that amantadine is ineffective as monotherapy. Amantadine increased the sustained virologic response of certain treatment naïve patients when used in combination with interferon, and may be effective as an adjunct to interferon-based combination therapy in some patients who have failed or relapsed on prior therapy. Factors such as small sample size, patient characteristics, and differences in treatment protocols including amantadine preparation and duration of therapy might explain the conflicting observations of various studies. Further investigations are needed to define optimal dosing and formulation of amantadine, and its appropriate role in management of CHC infection.

Peginterferon alpha-2a combination therapies in chronic hepatitis C patients who relapsed after or had a viral breakthrough on therapy with standard interferon alpha-2b plus ribavirin: a pilot study of efficacy and safety

There are no established therapeutic regimens for hepatitis C virus (HCV) patients who relapse following treatment with interferon alpha-2b and ribavirin or those who break through while on interferon alpha-2b and ribavirin. We therefore evaluated various combination therapies in HCV patients who relapsed or experienced a viral breakthrough. Patients (n = 124) were randomized to 48 weeks of treatment with once-weekly subcutaneous injections of 180 microg pegylated (peg-) interferon alpha-2a plus oral ribavirin (800-1000 mg/day), mycophenolate mofetil (2 g/day), amantadine (200 mg/day), or ribavirin and amantadine and followed for an additional 24 weeks. The sustained virologic response was higher in patients administered peginterferon alpha-2a plus ribavirin (38%) or ribavirin and amantadine (45%) than in those administered peginterferon alpha-2a plus mycophenolate mofetil (17%) or amantadine (10%). As in previous studies, patients with genotype non-1 and those with lower viral loads had better responses than those with genotype 1 and high viral loads, though the differences did not reach significance. The four treatment regimens had similar safety profiles, except that patients receiving ribavirin had greater maximal hemoglobin decreases. These findings suggest that the combination of peginterferon alpha-2a plus ribavirin or with ribavirin and amantadine is effective in some HCV patients who relapse after treatment with interferon alpha-2b plus ribavirin.

Retreatment of patients with chronic hepatitis C not responding to interferon/ribavirin combination therapy with daily interferon plus ribavirin plus amantadine

There is currently no accepted therapeutic regimen for patients with chronic hepatitis C who failed to respond to standard combination treatment with interferon-alpha plus ribavirin. We investigated triple combination treatment with induction dosing of interferon-alpha plus ribavirin plus amantadine in these difficult-to-treat patients. Nonresponders (n = 67), breakthroughs (n = 16) and relapsers (n = 19) to previous interferon/ribavirin combination treatment of at least 6 months were included. For the first 16 weeks, patients received interferon-alpha2a 6 MU daily, ribavirin 800-1200 mg/d, and amantadine 200 mg/d. In cases of undetectable HCV RNA at week 12, treatment was continued with interferon-alpha2a 6 MU every other day and the same doses of ribavirin and amantadine until week 48. In cases of HCV RNA positivity at week 12, treatment was stopped. A total of 102 patients were enrolled (80%: genotype 1, 19%: cirrhosis). HCV RNA was negative in 35/102 patients (34%) at week 12 and in 27/ 102 patients (26%) at the end of treatment. Virological response was sustained in 15/102 patients (15%). On-treatment virological response was higher in previous relapsers/breakthroughs than in previous nonresponders (week 12: 49% vs. 27%, p < 0.05; week 48: 46% vs. 16%, p < 0.01) but no such difference was found for sustained virological response (20% vs. 12%, NS). In conclusion, triple combination treatment with daily interferon-alpha plus ribavirin plus amantadine for 3 months can induce virological response in a considerable number of nonresponders/relapsers to previous dual combination treatment, but the sustained virological response rate remains low.

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.

[Interferon, ribavirin and amantadine in prior nonresponders to interferon and ribavirin therapy with chronic hepatitis C (genotype 1)]

OBJECTIVE

Despite advances in the treatment of chronic hepatitis C virus (HCV), the disease persists after treatment with interferon and ribavirin in a large percentage of patients and other therapeutic options are lacking. We investigated the efficacy of retreatment with antiviral therapy including amantadine.

EXPERIMENTAL DESIGN

prospective and open pilot study.

PATIENTS

Thirty-nine patients with chronic HCV, genotype 1, who were nonresponders to interferon and ribavirin were included. The patients were given repeat treatment with interferon-alpha 2A (9 MU/week), ribavirin (1,000-1,200 mg/day) and amantadine (200 mg/day) for 48 weeks.

RESULTS

HCV-RNA was undetectable in 5 patients in week 48 (12.8%) and in only 2 patients after 24 weeks of follow-up (5.1% of sustained responses). In patients with basal viremia of < 8 105 U/ml the probability of response at the end of treatment and of sustained response was 26.3 and 10.5%, respectively; in patients with elevated viremias response was 0%.

CONCLUSIONS

In patients with chronic HCV genotype 1 without response to interferon and ribavirin, triple antiviral therapy with interferon, ribavirin and amantadine is not useful.