A multicentre randomized controlled trial of recombinant interferon-alpha-2a in the treatment of patients with chronic hepatitis C

Can J Gastroenterol Vol 11 No 7 October 1997 579 M Komatsu, T Ono, K Nakajima, et al. A multicentre randomized controlled trial of recombinant interferon-alpha-2a in the treatment of patients with chronic hepatitis C. Can J Gastroenterol 1997;11(7):579-582. Sixty-one chronic hepatitis C patients were randomly assigned to receive either 6x10 or 9x10 U of recombinant interferon-alpha-2a (IFN -2a) six days a week for the first two weeks of treatment, followed in both cases by 6x10 U three days a week for the next 22 weeks. In the low dose group, 11 patients showed a complete response maintained for at least six months, 12 responded but then relapsed and nine did not respond; the corresponding figures in the high dose group were 10, 15 and five patients, respectively. The differences between groups are not statistically significant. Thus, this study provides no evidence of therapeutic benefit from increasing the initial dose of IFN -2a. In both treatment groups, complete responders had significantly lower pretreatment viral titres than nonresponders and were significantly more likely to be infected by type 2a versus type 1b virus.

I n the United States and Europe, administration of inter- feron (IFN) for treatment of hepatitis C is usually initially intermittent (three times a week) (1)(2)(3)(4).In Japan, however, IFN is generally administered six times a week for the first one to four weeks; only then is a three-times-a-week regimen initiated and continued for the remainder of the severalmonth treatment period.Japanese physicians also typically employ higher individual doses of IFN than those used in western countries, so the total IFN dose is greater.
The Japanese treatment regimen has proven effective: although the percentage of patients with long term normalization of transaminase levels is relatively low -about 30% (5,6) -the rarity of spontaneous recovery in hepatitis C patients renders this a very significant improvement in clinical outcome.IFN treatment is expensive, however, and is associated with various adverse reactions.In view of these economic costs and the physical burdens placed on the patient, the efficacy rates reported to date cannot be considered satisfactory.Further study is needed to determine the optimal dose and administration schedule for IFN.
In an effort to improve the effectiveness of IFN treatment in patients with chronic hepatitis C, we carried out a controlled trial using two different doses of IFNa-2a.Our hypothesis was that increasing the daily dose of IFN in the initial treatment period would improve the effectiveness of IFN therapy.

PATIENTS AND METHODS
Study design: Sixty-five patients with chronic hepatitis C from eight hospitals were enrolled.In all patients, hepatitis C virus (HCV)-RNA was detected by polymerase chain reaction (PCR).All patients were positive for anti-HCV antibody and were diagnosed histologically as having chronic hepatitis.All patients had no history of IFN treatment, and tests for hepatitis B surface antigen were negative in all cases.After informed consent was obtained, the patients were randomly assigned to two groups: group A (n=33) and group B (n=32).In group A, 6x10 6 U IFNa-2a was administered six days per week for two weeks, followed by the same dose three days per week for 22 weeks.The total dose of IFN was 468x10 6 U.In group B, the initial dose was 9x10 6 U six days per week for two weeks, followed by the same regimen of 6x10 6 U three days per week for 22 weeks, as per group A. The total dose of IFN was 504x10 6 U.
Four patients dropped out of the study due to adverse reactions or for personal reasons.In group A, one patient dropped out after developing depression and another after experiencing arm numbness.In group B, one patient stopped due to the appearance of heart failure and another was lost to follow-up because of a job transfer.Therefore, 61 patients were studied, 31 in group A and 30 in group B. The two groups did not differ in age, sex, histological type, alanine aminotransferase (ALT) value immediately before IFN treatment, HCV-RNA titre or HCV genotype (Table 1).
For evaluation of effectiveness, patients who had ALT values within the normal range for six months after completion of IFN treatment and in whom HCV-RNA could not be detected at the time, were defined as complete responders.Responders who relapsed were patients who had normal ALT values and negative HCV-RNA findings upon completion of IFN treatment, but in whom HCV-RNA later reappeared.All other patients were considered nonresponders.Laboratory measurements: Serum was obtained aseptically and immediately frozen at -40 to -80°C; it was then thawed just before testing.ALT values were measured immediately before the start of IFN administration, weekly for the follow-   ing month, and monthly for the remainder of the study period.Anti-HCV body was measured by ELISA (C-100-3).HCV-RNA qualitative analysis was performed on three occasions -immediately before, immediately after and six months following completion of IFN administration -by the reverse transcription nested PCR using the 5¢-noncoding region as primer (7,8).The quantitative HCV-RNA titre was measured by the multicyclic PCR method using the 5¢-noncoding region as primer (9).
In 50 patients whose serum was preserved before administration, the viral genotype was identified by PCR using the type-specific core region primer according to the method of Okamoto et al (10).Types 2, 3 and 4 noted by Okamoto et al correspond to types 1b, 2a and 2b of Simmonds et al (11).Statistical analysis: Results are presented as mean ± SD, and as percentages of total patients.Statistical analysis was performed using the Mann Whitney U test and Student's t test.For multivariate analysis, a stepwise regression analysis was used.P<0.05 was considered statistically significant.

RESULTS
In both treatment groups, IFN administration produced a decrease in ALT values that reached statistical significance after one month of treatment.This trend was also observed during treatment and six months after cessation of administration.However, there was no significant difference in ALT values between groups A and B at any time (Figure 1).
The ALT values of 11 patients (35.5%) in group A and 12 (40.0%) in group B remained within the normal range for more than six months after completion of IFN therapy in group A; this difference was not statistically significant.HCV-RNA findings, which had been positive in all patients before IFN administration, became negative immediately after completion of IFN administration in 16 group A patients (51.6%) and 19 group B patients (63.3%).By six months after cessation of treatment, however, there was no longer any difference between groups: 10 patients in each group had negative findings (32.3% of group A patients and 33.3% of those in group B).
The outcome of IFN treatment was significantly correlated with the amount of HCV-RNA before treatment: log 10 HCV-RNA titres in complete responders -6.5±1.6 copies/mL -were significantly lower than the titres of 8.0±1.1 copies/mL in responders who relapsed and 8.2±0.8 copies/mL in nonresponders.
Treatment outcome was also correlated with HCV genotype.As shown in Table 3, among the 33 patients tested for HCV genotype, type 1b was found in six of 33 complete responders (18.2%), in 18 of 33 responders who relapsed (54.5%) and in nine of 33 nonresponders (27.3%).Expressed another way, 18.2% of the 33 patients known to be infected by this genotype responded completely, 54.5% responded but later relapsed and 27.3% did not respond.By contrast, of the 13 patients known to be infected by HCV type 2a, six (46.2%) responded completely and seven (53.8%) responded but later relapsed; there were no nonresponding patients in this group.As implied by the combination of these results with those in the previous paragraph, the log 10 HCV-RNA titre was significantly higher in patients infected by type 1b virus (7.7±1.4 copies/mL) than in those with infected by type 2a (6.5±1.5 copies/mL).
Stepwise regression analysis of the independent factors that contribute to complete response, such as sex, age, level of serum ALT, method of IFN administration, histology, amount of serum HCV-RNA and HCV genotype, revealed that only the amount of serum HCV-RNA was significant (P=0.0015).

DISCUSSION
Factors influencing the effectiveness of IFN treatment in patients with chronic hepatitis C include: HCV-RNA titre, HCV genotype, HCV genetic diversity, histological degree of liver injury, and the dose, administration method and period of administration of IFN.
It has been reported that the efficacy of IFN treatment increases with the total dose (12)(13)(14).However, the incidence of adverse reactions also increases with the dose.It is therefore very important to consider not only the benefits of IFN but also its risks and costs to determine the optimum IFN dose.
In Japan, the most widely used treatment regimen is sixtimes-a-week IFN administration for two weeks, to provide rapid, potent inhibition of viral growth, followed by intermittent (three times weekly) administration for a total of six months.Reports suggest that, for a total dose, this regimen Can J Gastroenterol Vol 11 No 7 October 1997 581 Recombinant interferon-alpha-2a and chronic hepatitis C  may be more effective than either three-or six-times-a-week administration throughout the entire course of IFN treatment (14).However, there have been few controlled studies to determine the optimum dose in the initial treatment period.
We therefore carried out a controlled study in which all patients were dosed according to the basic Japanese treatment schedule, but group A received 6x10 6 of IFN six days per week through the initial two-week treatment period while group B received 9x10 6 U; both groups then received 6x10 6 three times a week for the remaining 22 weeks.The total IFN dose was thus 468x10 6 U in group A and 504x10 6  in group B, a fairly modest difference.We hypothesized, however, that the higher initial dose would have a favourable effect on response to treatment.
Results did not support this hypothesis.No statistically significant differences between the two groups were observed in ALT levels during administration, in ALT normalization rates immediately after administration or at later times, or in rates of HCV-RNA negativity either immediately after or six months following cessation of treatment.Although the percentage of nonresponders was lower in group B than in group A, this difference was not significant.We therefore conclude that increasing the dose of IFN to 9x10 6 U during the initial treatment period has no advantages.
Kasahara et al ( 15) compared the effects of administering IFNa three times per week for a period of either 28 or 52 weeks.They reported that relapses after cessation of IFN treatment were significantly reduced in the 52-week treatment group, with nonresponders amounting to 30% of the total patient population.In the present controlled study, the percentage of nonresponders in group A was about the same as that reported by Kasahara et al (15); in group B, however, the percentage of nonresponders fell to just 16%, the difference accounted for by responders who relapsed.The combination of our results with those of Kasahara et al (15) supports the possibility that the efficacy rate can be increased and relapses suppressed by extending the dosage regimen employed in group B over a longer period.
In the present study, the HCV-RNA titres in complete responders were significantly lower than those in nonresponders.We also found, as others have reported (15)(16)(17)(18), that the percentage of complete response was lower in patients with HCV genotype 1b than in those with genotype 2a.However, because the viral titre was higher in patients infected with type 1b virus than in those infected with type 2a, it is not clear whether the HCV genotype is an independent virus-specific factor that influences the effectiveness of IFN therapy.In any case, it seems clear that virus characteristics have a major effect on response to treatment.Thus, further research is required to determine how viral characteristics may affect the choice of IFN dosage regimen.

Figure 1 )
Figure 1) Serial alanine aminotransferase (ALT) levels in patients with chronic hepatitis C receiving interferon therapy.*P<0.05

TABLE 1 Patient characteristics at entry into the trial
The difference between group A and B was not statistically significant in any item.*Values are mean ± SD.ALT Alanine aminotransferase; HAI Histological activity index; HCV Hepatitis C virus