Viral, host and interferon-related factors modulating the effect of interferon therapy for hepatitis C virus infection

The estimated prevalence of hepatitis C virus infection in the US is approximately 1.8%. Although interferon monotherapy and combination therapy of interferon with ribavirin represent mainstay for treating HCV infection, the rate of sustained virologic response remains suboptimal. The growing evidence suggested that the clinical sequence and treatment response of chronic hepatitis C are determined by a dynamic, complex tripartite relationship among HCV infection, the host immune response, and the effect of different interferon regimens. The treatment response is associated with various viral factors including the pretreatment viral level, dynamic change of viral level during treatment, viral genotype quasispecies and nucleotide mutation in nonstructural protein 5A of hepatitis C virus. Host factors that may affect treatment response include age, gender, race, HLA alleles and the host immune responses. Interferon regimens, including type, dose, frequency and duration of treatment and combination of interferon with other anti-HCV agents also alter the therapeutic response. Understanding these complicated interaction may provide better insights into the mechanism(s) of interferon response, leading to more effective clinical application of interferon therapy.     

Predictors of sustained response, relapse and no response in patients with chronic hepatitis C treated with interferon-α

Summary. Three main patterns of response are seen when interferon-α (IFN-α) is used for the treatment of chronic hepatitis C: 1 sustained response with alanine-aminotransferase (ALT) normalization that is maintained after cessation of therapy, with or without clearance of serum hepatitis C virus (HCV) RNA; 2 transient response with ALT normalization during therapy followed by relapse after its withdrawal, and 3 no response with no or only partial reduction in ALT levels. In order to define variables that could predict each of these three types of response we studied 321 cases of chronic hepatitis C treated with IFN-α in two consecutive trials conducted in our Unit. By univariate analysis, age < 45 years (P < 0.01), known disease duration < 60 months (P < 0.01), normal gamma-glutamyltranspeptidase (γGT) levels (P < 0.01) and infection by HCV genotype 2 or HCV genotype 3 (P < 0.01) were found to be statistically associated with sustained response while age > 45 years (P < 0.01), body weight (P= 0.05), cirrhosis (P < 0.01) and elevated γGT levels (P < 0.01) were associated with no response. By multivariate analysis sustained response was predicted by HCV genotype 2 (P < 0.01) and HCV genotype 3 (P < 0.01), known disease duration (P < 0.01), patient's age (P < 0.05) and associated with the use of a more aggressive treatment schedule (P < 0.05). Transient response with relapse was predicted by known duration of disease (P < 0.05), HCV genotype 1 (P < 0.05) and female sex (P < 0.05). No response was statistically associated with elevated γGT levels (P < 0.01), higher body weight (P < 0.05) and with the less aggressive regimen of 3 MU of natural IFN-α given three times weekly for 6 months (P < 0.05). These results indicate that the HCV genotype as well as the schedule of treatment greatly affect the pattern of response to IFN in chronic hepatitis C and allow us to define criteria to predict which type of response is more likely in individual patients.     

Serum levels of anti-hepatitis C virus IgM core antibodies may predict the response to interferon-α therapy in chronic hepatitis C

SUMMARY. We measured the optical densities (OD) of serum anti-hepatitis C virus IgM core antibodies in 40 HCV-positive patients (24 males and 16 females) with histologically proven chronic active hepatitis but without cirrhosis. All patients were treated with i.m. injections of 3 MU thrice weekly of interferon-α (IFN-α) for 6 months and followed-up monthly. Optical densities were evaluated in thawed sera before beginning treatment and 6 months after completion, and in fresh sera obtained at the end of an 8–12-month follow-up period. Patients were grouped into three categories according to the OD obtained: <0.3 (negative test): 0.3-0.6 (intermediate positivity): >0.6 (high positivity). According to the response to treatment during the follow-up period, patients were further divided into three classes: sustained responders: relapsers or partial responders: non-responders. In each patient, the OD values were similar in the three determinations before, after therapy and at the end of the follow-up period. All patients with an intermediate positive test for anti-HCV IgM core antibodies were relapsers or partial responders, and all patients with high OD values were non-responders. Conversely, 71% of the patients with a negative test were sustained responders. We conclude that this cheap and easily performed test may be useful in predicting the response to IFN therapy.     

Re-treatment of interferon-resistant patients with chronic hepatitis C with interferon-α

Summary. Non-responders to 6-months treatment with recombinant interferon (rIFN)-α, 3 MU thrice weekly (primary non-responders) were treated for 6 further months with the same therapy or with a double dose of rIFN-α or with a different type of IFN (L-IFN). 112 primary non-responders were randomly enrolled into four groups of 28 patients each over a period of 4 years and were followed up for 6 months: group A continued the same dose of rIFN-α, group B was treated with the same rIFN-α but received a double dose (6 MU thrice weekly), group C received L-IFN, 3 MU thrice weekly, and group D stopped IFN therapy and did not receive any treatment. Patients were examined at monthly intervals and response was defined as a complete normalization of alanine amino transferase (ALT). The four groups were homogeneous as to age, sex, duration of the disease, probable source of infection, histological diagnosis, ALT and γ glutamyl transferase (γGT) levels. No patient discontinued therapy for side-effects. Further treatment with rIFN-α 3MU thrice weekly (group A) induced normalization of ALT levels in four patients (14%); treatment with double-dosed rIFN-α (group B) induced normalization of liver enzymes in six cases (21%); a different type of interferon (L-IFN) (group C) achieved normalization of serum ALT in five patients (18%). None of 28 primary non-responders who did not receive any treatment (group D) showed normalization of ALT levels. None of the patients was anti-HCV negative at the end of the study and no statistically significant difference was noted between responders and non-responders to the second course of IFN therapy as to age, sex, duration of the disease, ALT and γGT levels at the end of the trial. Overall at the end of the study the primary non-responders with normal levels of ALT were 15/112 (13%), with a therapeutic advantage of 7%. No statistically significant difference in the response rate was found among patients who continued IFN therapy, but prolongation of rIFN-α treatment at double dosage seems to be the best therapeutic regimen.     

Case Report: Agranulocytosis induced by interferon-α therapy for chronic hepatitis C

A 60-year-old woman presented with chronic active hepatitis C whose HCV-RNA genotype was II according to Okamoto's classification and serum HCV-RNA concentration was 10⁴ copies/mL. Agranulocytosis was induced 13 days from the commencement of interferon (IFN)-α 2b (6 MU/day) therapy, so the IFN therapy was immediately discontinued. The agranulocytosis improved rapidly with the administration of a granulocyte colony stimulating factor (G-CSF). The possibility that IFN was associated with maturational arrest of myeloid progenitor cells was considered. During the course of 3 years of follow-up, her liver function has remained normal and serum HCV-RNA remains negative.     

Clinical predictors of response to recombinant interferon-α treatment in patients with chronic non-A, non-B hepatitis (hepatitis C)

SUMMARY. Chronic non-A, non-B hepatitis (NANBH) is a common and often progressive liver disease. Based on current serological tests, hepatitis C virus (HCV) infection is responsible for most cases. Interferon-α (IFN) treatment at a dose of 3 × 10⁶ units given three times per week for 24 weeks has been shown to be effective in normalizing serum alanine aminotransferase (ALT) levels and reducing hepatic inflammation in approximately 40% of these patients. The purpose of this study was to identify pretreatment characteristics in patients with chronic hepatitis C(CH-C) which would best predict a favourable response to IFN treatment (normalization of serum ALT). One hundred and sixty-three adult patients who had participated in a large multi-centre treatment trial were included in the study group: 84 had been treated with 3 × 10⁶ units of recombinant IFN-α-2b (rIFN) subcutaneously three times per week for 24 weeks and 79 patients had been treated with 1 × 10⁶ units rIFN in the same dosage schedule. Forty-one pretreatment historical, clinical, laboratory and histological variables were evaluated. In addition, early biochemical improvement during treatment was evaluated as a predictor of ultimate response. Univariate analysis identified six variables (dose, dose m^-2, weight, body surface area, ongoing ethanol use, white blood cell count and the presence of symptoms) as potential predictors of response (two-tailed, P < 0.15). By multivariate analysis, however, only the 3 × 10⁶ dose of rIFN was independently predictive of response (P < 0.01). When the analysis of response was confined to those patients who received treatment with 3 × 10⁶ units of rIFN, seven variables [body weight, surface area, dose m^-2, current ethanol use, serum albumin and the presence of chronic persistent hepatitis (CPH) on entry liver biopsy] were more frequent in patients who responded to therapy. In a multivariate model, only CPH and body weight predicted an increased likelihood of response (P < 0.01). However, the model was not a sensitive predictor of response as only 18% of the study group had CPH on liver biopsy. A decrease in serum ALT levels within the first 12–16 weeks of rIFN treatment was found to be the strongest indicator of an ultimate response to treatment. Thus, assessment of early response to IFN treatment is the only practical means of predicting complete response and avoiding prolonged and unnecessary therapy in those with little chance of response.     

High-dose natural interferon-α therapy for chronic hepatitis C with a high viral load: Predictors of efficacy

BACKGROUND: The effectiveness of interferon against hepatitis C has been found to be greatly affected by viral factors. However, few controlled interferon trials have involved seemingly intractable cases of chronic hepatitis C. METHODS: In 44 patients with high hepatitis C virus RNA levels (> or = 10(5) copies/mL), we carried out a prospective, controlled study of two natural interferon-alpha regimens, seeking predictors of therapeutic efficacy. Total natural interferon-alpha doses over 6 months in two groups were 780 and 840 million units, respectively. RESULTS: High therapeutic efficacy was achieved with no significant outcome difference between the regimens. The virus eradication rate was 35% and the rate of sustained biochemical response was 45% for both regimens. Multivariate logistic regression analysis identified viral genotype as the only significant predictor of success in viral eradication. CONCLUSIONS: Hepatitis C virus genotype 2 showed high sensitivity to interferon-alpha and this therapy can be recommended even for patients with a high viral load of this genotype. In contrast, with genotype 1b, cure was extremely difficult in cases with 10(7) or more copies/mL with a single 6-month course of interferon-alpha.     

Efficacy and side effects of intermittent recombinant interferon-α2a in chronic aggressive hepatitis C: With or without initial daily administration

To investigate the therapeutic effect and incidence of side effects of recombinant interferon-α2a (IFN-α) in chronic aggressive hepatitis C under stratification by administration mode, a study was conducted by assigning patients to either group A (daily consecutive administration of 9 million units (MU) IFN-α for 2 weeks and, thereafter, 3 MU intermittently 3 times weekly for 22 weeks) or group B (exclusively intermittent administration; 9 MU IFN-α twice weekly or 6 MU IFN-α thrice weekly for 24 weeks). The 28 patients in group A received IFN-α for 24 weeks up to a total dose of 324 MU and the 53 patients in group B received the same for 24 weeks up to a total dose of 432 MU. When recovery was defined as the absence of hepatitis C virus (HCV)-RNA 6 months after the completion of treatment, the rate of recovery for group A was 32.1% and that for group B was 37.7%, the latter being higher but without significance. Side effects in groups A and B consisted of leucopenia occupying 14.3 and 7.5%, respectively, and thrombocytopenia occupying 42.9 and 11.3%, respectively; group B exhibited lower values for both side effects. No difference was detected between these groups in other side effects, including pyrexia, generalized malaise, arthralgia or psilosis. Intermittent administration from the outset permitted shortened duration of hospitalization and earlier rehabilitation. Intermittent administration of INF-α is required when treating patients with chronic hepatitis C showing lower leucocyte or platelet counts.     

Diabetes mellitus reduces the therapeutic effectiveness of interferon-α2b plus ribavirin therapy in patients with chronic hepatitis C

Aim: Patients with chronic hepatitis C (CHC) often have diabetes mellitus (DM). However, it is unknown whether DM affects patient response to interferon (IFN) plus ribavirin therapy. Therefore, the aim of this study was to examine the influence of DM on the outcome of IFN-alpha2b plus ribavirin therapy. Methods: In a cohort of 110 patients with CHC, the outcome of 6 months of IFN-alpha2b plus ribavirin therapy was evaluated by comparing the patients with and without DM. Results: There were 46 sustained-responders; 64 patients did not become sustained responders. Higher age (P = 0.015), lower platelet counts (P = 0.036), hepatitis C virus (HCV) serotype 1 (P = 0.001), advanced liver fibrosis (P = 0.004), and the presence of DM (P = 0.007) were significantly associated with not becoming a sustained-responder. Seventeen CHC (15%) patients had DM. Sex ratio, age, body mass index, alanine aminotransferase levels, HCV-RNA titer, and HCV serotypes did not significantly differ between the patients with and without DM, while fasting plasma glucose, hemoglobin A1c and liver histological staging were significantly different. On multiple logistic regression analysis, HCV serotype 1 (odds ratio 8.743, 95% confidence interval 2.215-34.517; P = 0.002) and the presence of DM (odds ratio 8.657, 95% confidence interval 1.462-51.276; P = 0.014) were independently associated with not becoming a sustained-responder. Conclusions: The findings indicate that DM reduces the response to IFN-alpha2b plus ribavirin therapy in CHC patients.     

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

In primary interferon-α (IFN-α) nonresponders with chronic hepatitis C, retreatment with IFN-α 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-α alone or in combination with amantadine sulphate in nonresponders to previous IFN-α monotherapy. Fifty-five IFN-α nonresponders with chronic hepatitis C (mean age: 46.6 years) received IFN-α 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-α 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-α/amantadine sulphate, one patient; IFN-α/placebo, four patients). After 24 weeks follow-up a sustained virological response was observed in only two patients receiving IFN-α 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-α/amantadine sulphate treatment compared with those treated with IFN-α alone. IFN-α/amantadine sulphate combination therapy was well tolerated without any serious adverse events. In conclusion, retreatment with IFN-α and amantadine sulphate does not increase the low sustained virological response rates of IFN-α therapy in primary IFN-α nonresponders with chronic hepatitis C, but may lead to a sustained improvement of health-related quality-of-life.     

Hepatitis C virus RNA and long-term response to recombinant interferon-α2b in patients with chronic hepatitis C

Summary. The effectiveness of recombinant interferon-α2b (rIFN-α2b) in eradicating hepatitis C virus (HCV) RNA from serum has not been completely assessed. We studied 39 patients with compensated chronic hepatitis C diagnosed by liver biopsy and positive HCV RNA measured by polymerase chain reaction (PCR). Group I consisted of 26 patients treated with 3 MU of rIFN-α2b for 6 months; group II, 13 control patients observed for six months; and group III, 12 out of 13 patients from group n who subsequently received 5 MU of rIFN-α2b for 6 months. In group I, 11 out of 23 (47.8%) patients who completed treatment had an immediate response and five (21.7%) had a sustained response to therapy six months after treatment. No response was observed in patients from group II. In group III, 7 out of 12 (58.3%) patients who completed treatment had an immediate response and none had a sustained response. Considering all patients who completed rIFN-α2b treatment, HCV RNA remained positive at the end of therapy in three of five sustained responders (60%), six of 13 patients who relapsed (46.1%), and in all non-responders (100%). HCV RNA was positive 6 months after therapy in four (80%), 13 (100%). and 17 (100%) patients respectively. All patients with a sustained response had normal aminotransferase levels 18 months after therapy. We conclude that in chronic hepatitis C rIFN-α2b causes a significant immediate response but this is not sustained, only 2.8% of treated patients had a sustained loss of HCV RNA. Normal aminotransferase persist in the long term, despite persistence of HCV RNA.     

The interferon-α2b gene in Japanese patients with chronic viral hepatitis who developed antibodies after treatment with recombinant interferon-α2a

DNA was extracted from leucocytes of 23 Japanese patients with chronic viral hepatitis who received treatment with recombinant interferon-alpha 2a (IFN-alpha 2a) and nine healthy controls, as well as eight human cell lines of Caucasian or African origin. A part of the gene encoding IFN-alpha 2 was amplified by polymerase chain reaction and the sequence of nucleotides 1-231 was determined. Interferon-alpha 2a, -alpha 2b and -alpha 2c genes were tested for in five clones each from a patient or control, or a cell line, based on adenine or guanine at nucleotide positions 68 and 101. The IFN-alpha 2b gene was detected in all 160 clones from 23 Japanese patients and nine controls, but the IFN-alpha 2a or -alpha 2c gene was not found in any. Of five cell lines derived from Caucasians, four exhibited only the IFN-alpha 2b gene, while the remaining one exhibited both IFN-alpha 2a and -alpha 2b genes. Of three cell lines derived from Africans, one each showed only the IFN-alpha 2b or -alpha 2c gene, and the remaining one both IFN-alpha 2b and -alpha 2c genes. The 23 patients with the IFN-alpha 2b gene and chronic viral hepatitis included 10 who developed antibodies against IFN after treatment with recombinant IFN-alpha 2a. These results indicated a distinct geographical distribution of the three IFN-alpha 2 genes, and suggested the use of a recombinant IFN-alpha 2 preparation in agreement with the IFN-alpha 2 gene possessed by the recipient to avoid antibody responses.     

Long-term retreatment in chronic hepatitis C patients who were non-responders to an initial course of interferon-α2b

Nineteen patients with chronic hepatitis C who were virological non-responders (seven responder/relapse and 12 no response) to an initial 24-week course of interferon-α2b (IFN-α2b) at a dose of 3million units (MU) thrice weekly were retreated for an additional 48 weeks at the same dosing schedule and followed-up for another 24 weeks post-therapy. At the end of follow-up (week 72), six (32%) of the 19 patients were hepatitis C virus (HCV) RNA negative and were virological complete responders to retreatment. The viral genotypes in these six patients included two each with 1b and 3a, one with 2b, and another with 2a/2b; five of the six virological responder patients had cirrhosis. Significant predictors for successful retreatment included lower baseline HCV RNA concentrations prior to the first course of therapy, 2 log₁₀ reductions in serum HCV RNA during the initial treatment and classification into the virological ‘responder/relapse’ category after the first course of IFN (P < 0.01 for all observations). When the above factors were used to construct a predictive model to determine response to retreatment, it was found that the absence of a 2 log₁₀ drop in HCV RNA concentrations during the first course of IFN therapy was the most reliable indicator of non-response to retreatment (likelihood ratio = 10, P = 0.0014). In addition, the presence of HCV RNA at week 12 of retreatment was 100% predictive of virological non-response to the 48-week course of therapy. Our findings indicate that an additional 48-week course of IFN-α2b therapy at 3 MU thrice weekly will achieve a virological complete response in 60% of patients who had a 2 log₁₀ drop in HCV RNA during their first course of treatment, and measurement of week-12 HCV RNA during retreatment to identify non-responders is beneficial to patients as well as being cost-effective. Thus, a second course of IFN remains a viable option in a subgroup of non-responder patients, regardless of genotype or the presence of compensated cirrhosis.     

Predictive value of IgM antibodies to hepatitis C virus in patients with chronic hepatitis C undergoing interferon-α therapy. Analysis by two different methods

SUMMARY. To determine the predictive value of IgM anti-hepatitis C virus (HCV) testing in patients with chronic hepatitis C infections undergoing interferon-α (IFN-α) therapy, IgM anti-HCV reactivity was analysed by two different methods (non-commercial and commercial) in 19 patients and monitored at times 0 (pre-treatment), 3, 6, 12. and 24 months during follow-up. Eight patients were non-responders, five remained in sustained response 1 year after stopping treatment, and six had a relapse. No correlation between alanine transaminase (ALT) levels and IgM anti-HCV reactivity was found by either method in baseline samples. In addition, neither the presence nor absence of IgM anti-HCV in baseline samples, nor the loss of specific IgM reactivity during treatment, had any predictive value. Finally, no other parameters analysed (age, sex, risk group and histological diagnosis), were significantly associated with IgM anti-HCV reactivity in our study. In summary, these results suggest that baseline detection and monitoring of IgM anti-HCV reactivity are not useful in predicting the sustained response to IFN-α therapy in chronic hepatitis C infection.     

Interferon therapy in haemodialysis patients with acute hepatitis C virus infection and factors that predict response to treatment

In view of the high rate of chronicity of acute hepatitis C and the low efficacy of interferon (IFN) treatment in advanced liver disease, it may be beneficial to treat patients during the acute phase of the infection. Here we assessed the effects of variable-dose IFNα-2b treatment in haemodialysis patients with acute hepatitis C virus (HCV) infection, and identified factors that may predict response to this therapy. The study population included 67 patients, but 14 were excluded due to side-effects or because they were lost to follow-up. Seventeen patients who received no specific treatment were used as controls (Group 1). Sixteen and 20 patients received low-(3  M U) and high-dose (6–10  M U) IFNα-2b three times weekly for 3 months (Groups 2 and 3, respectively). Virological end-of-treatment response (ETR) was observed in 1 (5.6%), 13 (56.5%), and 17 (65.4%) patients in Groups 1, 2, and 3, respectively, and virological sustained response (SR) was observed in 1 (5.6%), 6 (26.1%), and 13 (50%) patients in the three groups. The rates of virological ETR and SR in the treated groups were significantly higher than those of the control group ( P  < 0.01 for all comparisons). In multivariate logistic regression analysis, single stranded confirmational polymorphysm (SSCP) band number ( P =0.02) was the only factor that was significantly associated with virological SR. In conclusion, IFN-α treatment initiated during the acute phase of HCV infection is associated with a higher rate of virological ETR and SR. This study suggested that quasispecies heterogeneity has predictive value with regard to virological SR.     

Clinical efficacy of intramuscular human interferon-βvs interferon-α2b for the treatment of chronic hepatitis C

Summary. We have conducted a randomized study to compare the efficacy and tolerance of human interferon (IFN) β vs recombinant IFN-α2b in patients with chronic active hepatitis C. Forty patients were included: 21 received IFN-α (group A) and 19 IFN-β (group B). IFN was administered intramuscularly at a dose of 6 MU three times a week (tiw) for 2 months (induction phase), followed by 3 MU tiw for 4 months. Clinical, epidemiological and pathological features were similar in the two groups. Normal alanine aminotransferase (ALT) values at the end of treatment was regarded as a response to therapy and the response rate was 57% (12/21) in group A and 5.2% (1/19) in group B ( P < 0.01). Both types of IFN induced a significant decrease in mean ALT values by the end of the induction phase ( P < 0.01). When the dose was reduced to 3 MU, a marked, but not significant increase in ALT, was seen in group B, whereas no increase was seen in group A. IFN-β was better tolerated and haematological adverse effects (platelet and leucocyte decrease) were less pronounced with IFN-β. Hence, human IFN-β was less effective than IFN-α in treating chronic hepatitis C virus (HCV). Doses of IFN-β of 3 MU intramuscular (IM) tiw were clearly insufficient and it remains to be established whether higher doses of intramuscularly IFN-β can be useful.     

Quantitative assessment of hepatitis C virus RNA in peripheral blood mononuclear cells during therapy with interferon-α2a

A significant number of patients with hepatitis C (HCV) treated with interferon (IFN) will initially clear their serum of HCV RNA, but will then have recurrence of viraemia either during or after therapy. One proposed mechanism for relapse is that HCV may persist in peripheral blood mononuclear cells (PBMCs) and that the PBMCs serve as a 'viral reservoir' that is resistant to IFN. To address this hypothesis, we performed serial, quantitative polymerase chain reaction (PCR) of HCV RNA in serum and PBMCs from 26 consecutive patients treated with IFN-α2a. Of the 26 patients, 11 (42%) did not clear virus from their serum during therapy and were termed non-responders. Five patients (19%) had sustained clearance of virus from serum and were termed complete responders. The remaining 10 patients (39%) initially eliminated HCV RNA from their serum, but had relapse of viraemia. They were termed partial responders. In all 10 partial responders HCV RNA was undetectable in PBMCs at the same time that it was undetectable in serum. When virus recurred in serum, it was preceded by or occurred at the same time as the return of virus in PBMCs. The results of our study indicate that PBMCs did not serve as an IFN-resistant 'viral reservoir' during therapy. Partial responders who transiently cleared virus from serum also cleared virus from PBMCs and the presence or titre of HCV RNA in PBMCs at the initiation of therapy did not predict response to therapy.     

Factors useful in predicting the response to interferon therapy in chronic hepatitis C

To determine how various factors influence the response to interferon (IFN) therapy, we retrospectively studied 157 consecutive Japanese patients with chronic hepatitis C who received various treatment schedules of IFN. They were divided into two groups on the bases of outcome. One group was comprised of 65 patients who achieved a sustained normalization of serum alanine aminotransferase (ALT) levels for at least 6 months after treatment, while the other group was comprised of 84 patients with persistent elevation of serum ALT levels, despite treatment. Genotyping of hepatitis C virus (HCV) was done by polymerase chain reaction (PCR) with genotype specific primers, analysing the variations in nucleotide sequence within the NS 5 region of the HCV genome, namely genotypes PT, K1, K2a and K2b. We then used a multivariate analysis to determine the factors related to mode of treatment, patient characteristics and HCV genotype in relation to the response to IFN therapy. Of the 16 factors analysed, the HCV genotype (genotype K2a or K2b, P < 0.0008), treatment schedule (intermittent administration following a daily schedule, designated as combined schedule, P > 0.0014) and liver histology just before treatment (chronic persistent hepatitis or mild chronic aggressive hepatitis, P < 0.0324) were the most strongly correlated with a normalizing response to IFN therapy. These results suggest that not only are the IFN treatment schedule and patient profile significant, but the properties of the virus also influences the response. However, as the IFN treatment schedule is the only changeable factor, it should be designed to maximize the benefit of IFN therapy.