Long-term clearance of hepatitis C virus following interferon α-2b or peginterferon α-2b, alone or in combination with ribavirin.

Sustained virologic response (SVR) is the standard measure for evaluating response to therapy in patients with chronic hepatitis C (CHC). The aim of this study was to prospectively assess the durability of SVR in the pivotal studies of peginterferon (PEG-IFN) α-2b or IFN α-2b. We conducted two phase 3b long-term follow-up studies of patients previously treated for CHC in eight prospective randomized studies of IFN α-2b and/or PEG-IFN α-2b. Patients who achieved SVR [undetectable hepatitis C virus (HCV) RNA 24 weeks after completion of treatment] were eligible for inclusion in these follow-up studies. In total, 636 patients with SVR following treatment with IFN α-2b and 366 with SVR following treatment with PEG-IFN α-2b were enrolled. Definite relapse (quantifiable serum HCV RNA with no subsequent undetectable HCV RNA) was reported in six patients treated with IFN α-2b and three patients treated with PEG-IFN α-2b. Based on these relapses, the point estimate for the likelihood of maintaining response after 5 years was 99.2% [95% confidence interval (CI), 98.1-99.7%] for IFN α-2b and 99.4% (95% CI, 97.7-99.9%) for PEG-IFN α-2b. Successful treatment of hepatitis C with PEG-IFN α-2b or IFN α-2b leads to clinical cure of hepatitis C in the vast majority of cases.

Adherence to assigned dosing regimen and sustained virological response among chronic hepatitis C genotype 1 patients treated with boceprevir plus peginterferon alfa-2b/ribavirin.

BACKGROUND: Adherence to therapeutic regimens affects the efficacy of peginterferon alfa (P) and ribavirin (R) therapy in patients with chronic hepatitis C virus genotype 1. AIM: To determine if medication adherence impacts efficacy [sustained virological response (SVR)] with triple therapy that includes boceprevir (BOC) plus P/R. METHODS: Adherence was determined in two Phase 3 clinical studies with BOC: SPRINT-2 (previously untreated patients) and RESPOND-2 (patients who failed previous therapy with P/R). Adherence to the assigned duration of the dosing regimen and adherence to the three times a day (t.d.s.) dosing interval of 7-9 h for BOC were assessed by the recording of data from patients' dosing diaries and by the amount of study drug dispensed and returned. RESULTS: Most patients (63-71%) adhered to ≥80% of their assigned treatment duration and achieved SVR rates of 86-90%. In contrast, patients who adhered to <80% of their assigned treatment duration achieved SVR rates of 8-32% (P < 0.0001), particularly low in patients who failed previous therapy (SVR = 8-15%). Different rates of adherence (<60% to >80%) to the t.d.s. dosing interval (7-9 h) with BOC did not influence the SVR rates (SVR = 60-83%) with the exception of patients who failed previous treatment and adhered to <60% of the t.d.s. dosing interval with BOC (SVR = 48-50%; P = 0.005). CONCLUSIONS: The achievement of an SVR is more dependent on adherence to the assigned duration of treatment than adherence to the t.d.s. dosing interval with boceprevir. Adherence to >60% of t.d.s. dosing with boceprevir is important in patients who failed previous therapy.

Interleukin 28B polymorphisms are the only common genetic variants associated with low-density lipoprotein cholesterol (LDL-C) in genotype-1 chronic hepatitis C and determine the association between LDL-C and treatment response.

Low-density lipoprotein cholesterol (LDL-C) levels and interleukin 28B (IL28B) polymorphism are associated with sustained viral response (SVR) to peginterferon/ribavirin (pegIFN/RBV) for chronic hepatitis C (CHC) infection. IL28B has been linked with LDL-C levels using a candidate gene approach, but it is not known whether other genetic variants are associated with LDL-C, nor how these factors definitively affect SVR. We assessed genetic predictors of serum lipid and triglyceride levels in 1604 patients with genotype 1 (G1) chronic hepatitis C virus (HCV) infection by genome-wide association study and developed multivariable predictive models of SVR. IL28B polymorphisms were the only common genetic variants associated with pretreatment LDL-C level in Caucasians (rs12980275, P = 4.7 × 10(-17), poor response IL28B variants associated with lower LDL-C). The association was dependent on HCV infection, IL28B genotype was no longer associated with LDL-C in SVR patients after treatment, while the association remained significant in non-SVR patients (P < 0.001). LDL-C was significantly associated with SVR for heterozygous IL28B genotype patients (P < 0.001) but not for homozygous genotypes. SVR modelling suggested that IL28B heterozygotes with LDL-C > 130 mg/dL and HCV RNA ≤600 000 IU/mL may anticipate cure rates >80%, while the absence of these two criteria was associated with an SVR rate of <35%. IL28B polymorphisms are the only common genetic variants associated with pretreatment LDL-C in G1-HCV. LDL-C remains significantly associated with SVR for heterozygous IL28B genotype patients, where LDL-C and HCV RNA burden may identify those patients with high or low likelihood of cure with pegIFN/RBV therapy.

Durability of sustained response shown in paediatric patients with chronic hepatitis C who were treated with interferon alfa-2b plus ribavirin.

Long-term studies in adults indicate that sustained virologic response (SVR) after combination treatment for chronic hepatitis C (CHC) predicts long-term clearance. Although peginterferon plus ribavirin is now standard care for children with CHC, long-term follow-up studies are not yet available. This study evaluated durability of virologic response over 5 years in children previously treated with interferon alfa-2b plus ribavirin (IFN/R). Ninety-seven of 147 children with CHC, who were treated with IFN/R and completed the 6-month follow-up in two previous clinical trials, participated in this long-term follow-up study. All were assessed annually for up to 5 years; patients with SVR were assessed for durability of virologic response. Children with SVR (n = 56) and those with detectable hepatitis C virus (HCV) RNA 24-week post-treatment (n = 41) were followed for a median of 284 weeks. Overall, 70% (68/97) of patients completed the 5-year follow-up. One patient with genotype 1a CHC had SVR and relapsed at year 1 of follow-up with the same genotype. Kaplan-Meier estimate for sustained response at 5 years was 98% (95% CI: 95%, 100%). Six patients with low-positive HCV RNA levels (n = 4) or missing HCV RNA at the 24-week follow-up visit (n = 2) in the initial treatment studies had virologic response during this long-term follow-up study. Linear growth rate was impaired during treatment with rapid increases in the immediate 6 months post-treatment. Mean height percentile at the end of the 5-year follow-up was slightly less than the mean pretreatment height percentile. Five patients experienced serious adverse events; none related to study drug exposure. SVR after IFN/R predicts long-term clearance of HCV in paediatric patients; growth normalized in the majority of children during the long-term follow-up. Similar long-term results could be expected after peginterferon alfa-2b plus ribavirin treatment.

Association of a polymorphism in the indoleamine- 2,3-dioxygenase gene and interferon-α-induced depression in patients with chronic hepatitis C.

Interferon (IFN)-α treatment for infectious diseases and cancer is associated with significant depressive symptoms that can limit therapeutic efficacy. Multiple mechanisms have been implicated in IFN-α-induced depression including immune, neuroendocrine and neurotransmitter pathways. To further explore mechanisms of IFN-α-induced depression and establish associated genetic risk factors, single nucleotide polymorphisms in genes encoding proteins previously implicated in IFN-α-induced depression were explored in two self-reported ethnic groups, Caucasians (n=800) and African Americans (n=232), participating in a clinical trial on the impact of three pegylated IFN-α treatment regimens on sustained viral response in patients with chronic hepatitis C. Before treatment, all subjects were free of psychotropic medications and had a score ≤20 on the Center for Epidemiologic Studies Depression Scale (CES-D), which was used to assess depressive symptom severity throughout the study. In Caucasians, a polymorphism (rs9657182) in the promoter region of the gene encoding indoleamine-2,3-dioxygenase (IDO1) was found to be associated with moderate or severe IFN-α-induced depressive symptoms (CES-D>20) at 12 weeks of IFN-α treatment (P=0.0012, P<0.05 corrected). Similar results were obtained for treatment weeks 24, 36 and 48. In subjects homozygous for the risk allele (CC, n=150), the odds ratio for developing moderate or severe depressive symptoms at treatment week 12 was 2.91 (confidence interval: 1.48-5.73) compared with TT homozygotes (n=270). rs9657182 did not predict depression in African Americans, who exhibited a markedly lower frequency of the risk allele at this locus. The findings in Caucasians further support the notion that IDO has an important role in cytokine-induced behavioral changes.

Hepatitis C treatment among racial and ethnic groups in the IDEAL trial.

Previous studies of chronic hepatitis C virus (HCV) treatment have demonstrated variations in response among racial and ethnic groups including poorer efficacy rates among African American and Hispanic patients. The individualized dosing efficacy vs flat dosing to assess optimaL pegylated interferon therapy (IDEAL) trial enrolled 3070 patients from 118 United States centres to compare treatment with peginterferon (PEG-IFN) alfa-2a and ribavirin (RBV) and two doses of PEG-IFN alfa-2b and RBV. This analysis examines treatment response among the major racial and ethnic groups in the trial. Overall, sustained virologic response (SVR) rates were 44% for white, 22% for African American, 38% for Hispanic and 59% for Asian American patients. For patients with undetectable HCV RNA at treatment week 4, the positive predictive value of SVR was 86% for white, 92% for African American, 83% for Hispanic and 89% for Asian American patients. The positive predictive values of SVR in those with undetectable HCV RNA at treatment week 12 ranged from 72% to 81%. Multivariate regression analysis using baseline characteristics demonstrated that treatment regimen was not a predictor of SVR. Despite wide-ranging SVR rates among the different racial and ethnic groups, white and Hispanic patients had similar SVR rates. In all groups, treatment response was largely determined by antiviral activity in the first 12 weeks of treatment. Therefore, decisions regarding HCV treatment should consider the predictive value of the early on-treatment response, not just baseline characteristics, such as race and ethnicity.

Clinical trial: interferon alpha-2b continuous long-term therapy vs. repeated 24-week cycles for re-treating chronic hepatitis C.

BACKGROUND: Treatment options are limited for patients with hepatitis C virus who do not experience sustained viral eradication with pegylated interferon and ribavirin therapy. AIM: To compare, in an open-label, randomized study, long-term continuous interferon alpha-2b treatment with repeated 24-week courses in patients with chronic hepatitis C virus that relapsed after prior interferon monotherapy. METHODS: A total of 499 patients received 24 weeks of interferon alpha-2b, 3 MIU administered 3 TIW. Responders (normal alanine aminotransferase and negative hepatitis C virus -RNA, n = 244) were then randomized to continuous interferon therapy (1, 2 or 3 MIU TIW depending on response) or cyclical therapy (3 MIU TIW for 24 weeks per relapse). Mean Knodell inflammation (I + II + III) and necrosis (IV) scores at baseline vs. year 2 were compared. RESULTS: Patients receiving continuous low-dose therapy vs. cycled therapy had larger reductions in inflammation (-3.9 vs. -3.1) and fibrosis (-0.49 vs. -0.24). Among both groups, the mean change was -3.4 for inflammation and -0.36 for fibrosis. Overall, 73% (95% CI: 67-79) of patients experienced reduced inflammation and 28% (95% CI: 22-34) had reduced fibrosis. CONCLUSIONS: Our results suggest hepatitis C virus patients experiencing viral suppression during long-term maintenance therapy with interferon demonstrate histological improvement. Further prospective trials testing this hypothesis are in progress.

Predicting response to initial therapy with interferon plus ribavirin in chronic hepatitis C using serum HCV RNA results during therapy.

In patients with chronic hepatitis C, 48 weeks of therapy with interferon (IFN) plus ribavirin results in a sustained virologic response of 40%. Preliminary analysis suggests that measuring HCV RNA at week 24, rather than week 12, might provide the best prediction of treatment response. To assess the clinical utility of serum HCV RNA determinations at different times during therapy as a predictor of a sustained virologic response we evaluated 912 treatment-naïve patients. Patients were randomized to receive IFN-alpha2b, 3 million units (MU) three times weekly (tiw), for 24 or 48 weeks with either ribavirin or placebo, and then followed for 24 weeks. Serum HCV RNA was measured at weeks 4 and 12 in patients treated for 24 weeks; at 4, 12, and 24 weeks during therapy in those treated for 48 weeks, and week 24 post-therapy in all patients. Sustained response was defined as loss of serum HCV RNA at week 24 follow-up. Other patients were considered virologic nonresponders. For patients receiving 48 weeks of combination therapy, detectable serum HCV RNA at week 24 predicted nonresponse (positive predictive value) in 99% of patients compared to 89% at week 12. In patients treated for 24 weeks, testing at week 12 was more predictive of nonresponse than testing at week 4 in the combination-therapy group but not in the monotherapy group. Hence, for combination therapy, testing for serum HCV RNA as a predictor of nonresponse is most accurate at week 24 of therapy; a positive test correctly identified 99% of nonresponders.

Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for initial treatment of chronic hepatitis C: a randomised trial.

BACKGROUND: A sustained virological response (SVR) rate of 41% has been achieved with interferon alfa-2b plus ribavirin therapy of chronic hepatitis C. In this randomised trial, peginterferon alfa-2b plus ribavirin was compared with interferon alfa-2b plus ribavirin. METHODS: 1530 patients with chronic hepatitis C were assigned interferon alfa-2b (3 MU subcutaneously three times per week) plus ribavirin 1000-1200 mg/day orally, peginterferon alfa-2b 1.5 microg/kg each week plus 800 mg/day ribavirin, or peginterferon alfa-2b 1.5 microg/kg per week for 4 weeks then 0.5 microg/kg per week plus ribavirin 1000-1200 mg/day for 48 weeks. The primary endpoint was the SVR rate (undetectable hepatitis C virus [HCV] RNA in serum at 24-week follow-up). Analyses were based on patients who received at least one dose of study medication. FINDINGS: The SVR rate was significantly higher (p=0.01 for both comparisons) in the higher-dose peginterferon group (274/511 [54%]) than in the lower-dose peginterferon (244/514 [47%]) or interferon (235/505 [47%]) groups. Among patients with HCV genotype 1 infection, the corresponding SVR rates were 42% (145/348), 34% (118/349), and 33% (114/343). The rate for patients with genotype 2 and 3 infections was about 80% for all treatment groups. Secondary analyses identified bodyweight as an important predictor of SVR, prompting comparison of the interferon regimens after adjusting ribavirin for bodyweight (mg/kg). Side-effect profiles were similar between the treatment groups. INTERPRETATION: In patients with chronic hepatitis C, the most effective therapy is the combination of peginterferon alfa-2b 1.5 microg/kg per week plus ribavirin. The benefit is mostly achieved in patients with HCV genotype 1 infections.

A randomized, double-blind trial comparing pegylated interferon alfa-2b to interferon alfa-2b as initial treatment for chronic hepatitis C.

This international, randomized, active-controlled, parallel-group, double-blind dose-finding study compared peginterferon alfa-2b (PegIntron) to interferon alfa-2b for the initial treatment of compensated chronic hepatitis C. We randomly assigned 1,219 subjects to receive either the standard three-times-weekly (TIW) interferon alfa-2b dose (3 MIU) or the once-weekly (QW) peginterferon alfa-2b (0.5, 1.0, or 1.5 microg/kg). Subjects were treated for 48 weeks and then followed for an additional 24 weeks. All 3 peginterferon alfa-2b doses significantly (P < or =.042) improved virologic response rates (loss of detectable serum HCV RNA) after treatment and after follow-up, as compared with interferon alfa-2b. Unlike the end-of-treatment virologic response, the sustained virologic response rate was not dose-related above 1.0 microg/kg peginterferon alfa-2b because of a higher relapse rate among patients treated with 1.5 microg/kg peginterferon alfa-2b, particularly among patients infected with genotype 1. All 3 peginterferon alfa-2b doses decreased liver inflammation to a greater extent than did interferon alfa-2b, particularly in subjects with sustained responses. No new adverse events were reported, and the majority of adverse events and changes in laboratory values were mild or moderate. In conclusion, peginterferon alfa-2b maintained (0.5 microg/kg) or surpassed (1.0, 1.5 microg/kg) the clinical efficacy of interferon alfa-2b while preserving its safety profile. The higher rate of virologic response during treatment with 1.5 microg/kg peginterferon alfa-2b in patients infected with genotype 1 and high viral levels warrants further evaluation.

The effects of interferon alpha-2b in combination with ribavirin on health related quality of life and work productivity.

BACKGROUND/AIMS: Interferon plus ribavirin is the most effective therapy for chronic hepatitis C. The aim of this study was to evaluate the effect of chronic hepatitis C and therapy on health-related quality of life and work functioning. METHODS: Nine hundred and twelve patients with hepatitis C infection were randomized in a controlled trial of Interferon alpha 2b 3 MU tiw for 24 or 48 weeks plus ribavirin 1000-1200 mg or placebo. Questionnaire-based assessments of health-related quality of life and work functioning were performed before, during, and after treatment. Outcome measures included the SF-36 Health Survey and additional generic and specific scales. Work functioning was assessed as missed days, shorter hours or less productivity at work. RESULTS: Pre-treatment, patients had significant impairment in five of eight SF-36 concepts compared to matched population norms. Sustained responders had a return to normal for four of these five concepts. Quality of life did not improve in non-responders. Improvements in histology, viral load or ALT values predicted improvements in quality of life. Sustained responders also had improvements in work functioning and productivity. CONCLUSIONS: Hepatitis C patients had impaired quality of life. After combination therapy, sustained virologic responders achieved benefits in their quality of life and work functioning.

The significance of baseline serum alanine aminotransferase on pretreatment disease characteristics and response to antiviral therapy in chronic hepatitis C.

We sought to determine whether pretreatment serum alanine aminotransferase (ALT) levels in patients with chronic hepatitis C virus (HCV) correlate with demographic features and other disease characteristics and whether these values influence response to therapy. A total of 1,744 patients with HCV received either interferon alfa-2b and placebo or combination interferon alfa-2b and ribavirin for 24 or 48 weeks. Of these, 105 individuals (6%) had minimally raised serum ALT determinations at entry visit of 1.3 x ULN cohort. Baseline ALT was not related to gender, race, baseline viral level, or HCV genotype. Using logistic regression analysis, the only demographic feature associated with ALT 1.3 x ULN, in all treatment groups (26 of 105, 24.8% for ALT 1.3 x ULN). We conclude that HCV patients with minimally raised ALT values (

Cost-effectiveness of 24 or 48 weeks of interferon alpha-2b alone or with ribavirin as initial treatment of chronic hepatitis C. International Hepatitis Interventional Therapy Group.

OBJECTIVE: Initial therapy with ribavirin and interferon alpha-2b results in a higher sustained virological response than interferon alone, but this regimen is expensive. We aimed to examine the cost-effectiveness of 24- or 48-wk initial treatment with combination therapy versus interferon alone for patients who have chronic hepatitis C. METHODS: Data from recent randomized clinical trials comparing combination therapy to interferon alone were applied to a previously published computer cohort simulation to project lifelong clinical and economic outcomes. Natural history and economic estimates were based on published literature, expert panel estimates, and actual variable cost and reimbursement data. RESULTS: Using treatment stopping rules, sustained viral negative response rates would be 33.1% and 39.8% for patients receiving 24 versus 48 wk of ribavirin/interferon, compared with 14.3% for 48 wk of interferon alone. Compared to the interferon alone strategy, 24 or 48 wk of combination therapy should prolong life expectancy by 1.4 to 2.0 yr at marginal cost-effectiveness ratios of $4,400 to $5,400 per discounted quality-adjusted life-year (DQALY) gained. Compared to 24 wk of combination therapy, 48 wk of combination therapy should prolong life expectancy by 0.6 yr at a marginal cost-effectiveness ratio of $7,700 per DQALY gained. The results were robust, with 24 or 48 wk of combination therapy remaining preferred and cost-effective in sensitivity analysis compared with interferon alone. CONCLUSION: For patients with chronic hepatitis C, 24 or 48 wk of ribavirin and interferon should prolong life and be cost-effective when compared with 48 wk, of interferon alone.

TT virus infection in patients with chronic hepatitis C virus infection--effect of primers, prevalence, and clinical significance. Hepatitis Interventional Therapy Group.

BACKGROUND/AIM: A novel DNA virus, TT virus (TTV), was recently identified in patients with post-transfusion non-A-G hepatitis. The aim of this study was to determine the prevalence and clinical significance of TTV infection in patients with chronic hepatitis C virus (HCV) infection. METHODS: We analyzed pretreatment serum samples from 171 United States and European patients who relapsed after interferon-alpha treatment and were recruited into an interferon-alpha-2b/ribavirin combination treatment trial. TTV DNA was detected by PCR using two different set of primers (TTV-A and TTV-B) derived from open reading frames 1 and 2, respectively. RESULTS: TTV was detected in 29.2% of the patients with the TTV-A primer set, 70.8% with the TTV-B primer-set, and 72.5% if positive by either/both sets of the primers. The amplicons generated by primer set A were sequenced and a phylogenetic tree was constructed. The 50 isolates belonged to group la (n=8), 1b (n=17), 2a (n=21), 2b (n=3), and 4 (n=1). There was no difference in demographic (age, sex distribution, estimated duration of HCV infection), biochemical (serum ALT levels), virologic (serum HCV RNA levels, HCV genotype distribution), or histologic scores, and their subsequent response to either interferon-alpha-2b or interferon-alpha-2b/ribavirin combination treatment. CONCLUSIONS: The prevalence of TTV infection reported previously may have been significantly underestimated, based on the primers originally described and used by most studies. Although TTV infection is very common in patients with chronic HCV infection, it has no identifiable clinical significance.

Clinical, virological and histological implications of GB virus-C/hepatitis G virus infection in patients with chronic hepatitis C virus infection: a multicentre study based on 671 patients.

To determine the prevalence, as well as the clinical, virological and histological implications of GB virus C/hepatitis G virus (GBC-C/HGV) infection in patients with chronic hepatitis C virus (HCV) infection, sera from 671 well-characterized patients with chronic HCV infection were tested for GBV-C/HGV RNA using a sensitive and specific reverse transcription 'nested' polymerase chain reaction (RT-nPCR). GBV-C/HGV RNA was detected in 65 of 671 (9. 7%) patients with chronic HCV infection. Importantly, GBV-C/HGV co-infection was not associated with any changes in indices of liver diseases, including serum alanine transaminase levels, Knodell score or histology activity index (HAI). In this cohort, GBV-C/HGV co-infection was weakly associated with a shorter mean estimated duration of HCV infection and a higher median HCV viraemia level. We conclude that GBV-C/HGV has minimal or no impact on liver disease activity in patients with chronic HCV infection. This data supports the notion that GBV-C/HGV may not be a hepatitis virus.

Interferon alfa-2b alone or in combination with ribavirin as initial treatment for chronic hepatitis C. Hepatitis Interventional Therapy Group.

BACKGROUND: Only 15 to 20 percent of patients with chronic hepatitis C have a sustained virologic response to interferon therapy. We compared the efficacy and safety of recombinant interferon alfa-2b alone with those of a combination of interferon alfa-2b and ribavirin for the initial treatment of patients with chronic hepatitis C. METHODS: We randomly assigned 912 patients with chronic hepatitis C to receive standard-dose interferon alfa-2b alone or in combination with ribavirin (1000 or 1200 mg orally per day, depending on body weight) for 24 or 48 weeks. Efficacy was assessed by measurements of serum hepatitis C virus (HCV) RNA and serum aminotransferases and by liver biopsy. RESULTS: The rate of sustained virologic response (defined as an undetectable serum HCV RNA level 24 weeks after treatment was completed) was higher among patients who received combination therapy for either 24 weeks (70 of 228 patients, 31 percent) or 48 weeks (87 of 228 patients, 38 percent) than among patients who received interferon alone for either 24 weeks (13 of 231 patients, 6 percent) or 48 weeks (29 of 225 patients, 13 percent) (P<0.001 for the comparison of interferon alone with both 24 weeks and 48 weeks of combination treatment). Among patients with HCV genotype 1 infection, the best response occurred in those who were treated for 48 weeks with interferon and ribavirin. Histologic improvement was more common in patients who were treated with combination therapy for either 24 weeks (57 percent) or 48 weeks (61 percent) than in those who were treated with interferon alone for either 24 weeks (44 percent) or 48 weeks (41 percent). The drug doses had to be reduced and treatment discontinued more often in patients who were treated with combination therapy. CONCLUSIONS: In patients with chronic hepatitis C, initial therapy with interferon and ribavirin was more effective than treatment with interferon alone.

Ineffectiveness of postexposure prophylaxis of rhinovirus infection with low-dose intranasal alpha 2b interferon in families.

Past studies conducted in Australian and American families have demonstrated that alpha 2b interferon (IFN) is effective in preventing rhinovirus-associated illnesses in exposed family members. IFN had been used by intranasal application for 7 days after exposure (5 x 10(6) IU/day). We used the same approach but with only 5 days of spraying (5 x 10(6) IU on day 1 and 2.5 x 10(6) IU on each subsequent day). This amount has been effective in studies involving seasonal prophylaxis. During the study period, a total of 178 rhinoviruses were isolated from the 199 enrolled families in Tecumseh, Mich. There were 434 courses of IFN use and 434 courses of placebo use. Although rhinoviruses were less frequently isolated from those using IFN than those using the placebo, no differences favoring IFN treatment could be found in any of the symptomatic episodes. In fact, more episodes were observed in IFN recipients than in placebo recipients, although the differences were not statistically significant. Additionally, there was no evidence of modification of the severity of episodes of illness. It was concluded that prevention of rhinovirus illness episodes postexposure required a dosage of at least 5 x 10(6) IU of IFN-alpha 2b.

Safety and tolerance of ocular administration of recombinant alpha interferon.

The safety, tolerance, and levels of drug in the nasal cavity produced by an ocular formulation of interferon were determined at four dosages in a placebo-controlled, double-masked trial. Interferon given by the ocular route was generally well tolerated, although a dose-related occurrence of subjective symptoms was detected.

Intranasal recombinant alfa-2b interferon treatment of naturally occurring common colds.

In a double-blind, placebo-controlled study, patients with naturally occurring common colds of less than or equal to 48 h duration were randomly assigned to receive nasal sprays of recombinant alfa-2b interferon at 10 or 20 MU/day or placebo four times per day for 5 days. The 10-MU (n = 74), 20-MU (n = 74), and placebo (n = 72) groups had comparable frequencies of documented rhinovirus colds (50 to 65%) and mean durations of pretreatment symptoms (26 to 27 h). The median duration of colds tended to be longer in the 20-MU group (10 days) than the 10-MU group (8 days) or placebo group (8 days) (P = 0.06). In those with proven rhinovirus colds treated within 24 h, the median duration was significantly longer in the 20-MU group (9 days) than in the placebo group (6 days). No differences favoring interferon treatment were found in respiratory symptom scores or resolution of specific symptoms. On days 5 and 7, nasal washings from compliant subjects with proven rhinovirus colds yielded rhinoviruses more often in placebo (47 and 48%, respectively) than in interferon (15 and 16%, respectively) recipients (P less than 0.02), but no differences in new respiratory illness occurrence were observed in household contacts. Interferon recipients had significantly higher frequencies of blood in nasal mucus (16 to 18%) than did placebo recipients (4%) during treatment. Antibiotics for presumed secondary infections were given more often in the 20-MU group (11%) than in the placebo group (0%) (P less than 0.01). Nasal sprays of recombinant alfa-2b interferon were not an effective treatment for natural colds and were associated with toxicity.