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Biomedical subjects

R Schvarcz

Publications and source records attributed to R Schvarcz.

At least 19 recordsLinked to original sources
PubMed2006

Pegylated interferon and ribavirin treatment for hepatitis C in haemodialysis patients.

Standard therapy for chronic hepatitis C (HCV) is pegylated interferon in combination with ribavirin. There is limited experience with either drug in dialysis [end stage renal disease (ESRD)]. Six haemodialysis patients, four with HCV genotype 1, one with genotype 4 and one genotype 2 were treated with pegylated interferon-alfa-2b (n = 4) and pegylated interferon-alfa-2a (n = 2) for 24-48 weeks according to genotype with a dose of 50 or 135 mug/week respectively. All patients were given reduced ribavirin doses, initially 200-400 mg/day. Ribavirin trough plasma concentrations were measured with a HPLC method previously developed for earlier treatment studies, aiming at a target concentration of 10-15 micromol/L. Interferon related side-effects were common, in one patient peg-alfa-2b was permanently reduced to 50 mug every 9-10 days with improvement in tolerance. Average ribavirin dose was 170-300 mg/day. Ribavirin-induced anaemia was treated with high doses of erythropoietin and low doses of iron. Blood-transfusions were not needed. All patients became HCV-RNA-PCR negative during treatment which was completed or nearly completed in four patients. One patient terminated therapy prematurely due to pronounced interferon related side-effects and another died of myocardial infarction probably not related to therapy. Three patients have remained HCV-RNA negative with extended follow-up, two of whom have had a successful kidney transplant. Pegylated interferons are likely to become a valuable addition for HCV therapy in ESRD and are possible to combine with ribavirin. However the pharmacokinetics and tolerability of both peg-alfa-2a and 2b need to be studied more closely in prospective studies before definite dosing recommendations can be made.

Adult↗
PubMed2004

Evidence that plasma concentration rather than dose per kilogram body weight predicts ribavirin-induced anaemia.

Ribavirin in combination with interferon alpha-2 or pegylated interferon is the standard treatment for chronic hepatitis C. The current dosage recommendations for ribavirin are based on body weight (bw). Ribavirin is mainly eliminated by the kidneys and we have recently shown that ribavirin plasma concentrations are determined primarily by renal function. It is therefore reasonable to hypothesize that side-effects of ribavirin, i.e. anaemia, should be more closely related to plasma concentrations of ribavirin than to the dose per kg bw. A total of 108 consecutive patients eligible for treatment of chronic hepatitis C were studied. Ribavirin concentrations in plasma were measured by high-performance liquid chromatography (HPLC)-UV after solid-phase extraction in trough samples taken 4, 8 and 12 weeks after the treatment commenced. A total of 213 samples were obtained and the change in the haemoglobin level and the creatinine concentration was measured in addition to ribavirin. The dose of ribavirin per kg bw did not correlate with the drop in haemoglobin level induced by ribavirin. The concentration of ribavirin was non-linearly related to the drop in the haemoglobin level as revealed by fitting a standard Hill equation type dose-response curve. The half maximal drop in haemoglobin was obtained at 4.4 microm. The results from this study suggest that the anaemia induced by ribavirin depends primarily on the concentration of ribavirin, and not on the dose per kg bw. This lends further support to the idea that ribavirin should be dosed according to renal function.

Adult↗
PubMed2001

Ribavirin treatment in dialysis patients with chronic hepatitis C virus infection--a pilot study.

Standard treatment for chronic hepatitis C is with interferon (IFN)-alpha and ribavirin for 6-12 months. In dialysis patients only interferon therapy is currently used due to the lack of knowledge concerning ribavirin dosage and side-effects. The aim of this study was to investigate if ribavirin can be added to interferon when treating dialysis patients with hepatitis C. Five patients on haemodialysis and one patient on peritoneal dialysis with chronic hepatitis C, five with genotype 1 and one with genotype 4, were given interferon-alpha2b 3 MU thrice weekly for 4 weeks, whereafter ribavirin 200-400 mg was added, for an intended total treatment period of 28 weeks. Ribavirin plasma concentrations were monitored, using HPLC. Four patients completed the treatment. One patient suffered marked side-effects from interferon and therapy was terminated. One patient developed heart failure and died after 14 weeks of treatment but the death was not considered treatment related. Based on plasma concentrations, ribavirin doses were frequently adjusted initially. The target concentration (10-15 micromol/L) was reached with average daily doses of 170-300 mg ribavirin. Ribavirin induced anaemia was managed with high doses of erytropoietin (20 000-30 000 IU/week). Five of six patients became hepatitis C virus (HCV)-RNA negative during treatment, but four relapsed post-treatment; one is HCV-RNA negative. Hence ribavirin, in combination with IFN-alpha, can be used to treat dialysis patients with HCV. However, this requires reduced ribavirin doses and close monitoring of ribavirin plasma concentrations and haemoglobin. Ribavirin-induced anaemia can be managed with high doses of erythropoeitin.

Adult↗
PubMed2000

Interaction between nelfinavir and tacrolimus after orthoptic liver transplantation in a patient coinfected with HIV and hepatitis C virus (HCV).

A 49-year old male patient with severe hemophilia A, coinfected with HIV and HCV, who underwent orthoptic liver transplantation because of hepatitis C cirrhosis is presented. We describe a strong interaction between nelfinavir and tacrolimus postoperatively, that caused a reduction of the dose of tacrolimus by a factor 70 compared with normal, to achieve therapeutic blood concentrations and to avoid toxic side effects. We suggest that nelfinavir inhibits the metabolism of tacrolimus because both compounds are well-known substrates for the cytochrome P450 isoenzyme CYP 3A4. The nelfinavir serum concentrations were not affected by the institution of tacrolimus. Although the interaction dramatically changed the tacrolimus dose-concentration relationship, the situation was manageable by frequent monitoring of blood concentrations of tacrolimus.

Drug Interactions↗
PubMed2000

HCV RNA levels during therapy with amantadine in addition to interferon and ribavirin in chronic hepatitis C patients with previous nonresponse or response/relapse to interferon and ribavirin.

Interferon (IFN) alpha in combination with ribavirin (RIB) is standard therapy for patients with chronic hepatitis C virus (HCV) infection. However, many patients do not respond with sustained HCV clearance to this therapy. At present, no accepted treatment strategy exists for these patients. Recent preliminary data have suggested that amantadine (AMA) is effective against HCV infection. In a pilot study, we treated 13 nonresponders and 10 response/ relapsers to previous IFN/RIB therapy with AMA 200 mg per day in combination with IFN 3 MU thrice weekly, and RIB 1000 mg per day for 24 weeks, with a 24-week follow-up period after end-of-treatment. At the end-of-treatment, 1 previous nonresponder and 5 previous response/relapsers were HCV RNA negative. At the end of follow-up, only 1 previous response/relapser remained HCV RNA negative and had a sustained response. During therapy, serum HCV RNA became undetectable in 4 previous nonresponders, of whom 3 had a breakthrough at week 24. Twenty-one patients continued therapy without dose reductions. One patient discontinued therapy prematurely due to sleeping disturbances, and another patient was withdrawn from therapy due to heavy alcohol intake. We conclude that the addition of AMA to IFN and RIB was well tolerated but had little, if any, impact on HCV RNA eradication in nonresponders or response/relapsers to previous IFN/RIB combination therapy.

Adult↗
PubMed2000

Determination of ribavirin in serum using highly selective solid-phase extraction and high-performance liquid chromatography.

A rapid assay for determination of ribavirin in serum using solid-phase extraction (SPE), high-performance liquid chromatography (HPLC), and UV-detection was developed. The SPE uses phenylboronic acid columns with an approximately 100% recovery for ribavirin. The concentration-peak area relation was linear (r > 0.995), from 1 to 64 microM in 100 microL serum. The limit of detection was 0.1 microM. The intraassay CV was 3.2% at treatment levels (9.7 microM) and 11.5% at 0.4 microM. The method is used to monitor patients undergoing ribavirin treatment for hepatitis C (HCV). Samples from HCV-infected patients with and without renal dysfunction have been analyzed without interference of endogenous compounds. It is concluded that the method is useful for routine therapeutic drug monitoring.

Antiviral Agents↗
PubMed1999

Histological and virological long-term outcome in patients treated with interferon-alpha2b and ribavirin for chronic hepatitis C.

Long-term virological and histological outcome following interferon-alpha2b (IFN-alpha2b) and ribavirin treatment for 24 weeks was studied in 20 patients with chronic hepatitis C who were without a lasting response to IFN as monotherapy. Following combination therapy, sustained virological response (SR) was achieved in 12 patients (i.e. hepatitis C virus (HCV) RNA negative in serum 6 months post-treatment). Eleven of these patients remained HCV RNA negative in serum 2 years post-treatment. A virological long-term response (LTR) was more frequent in patients with a previous end-of-treatment response to IFN monotherapy than in non-responders. Liver histology at follow-up, >/=24 months post-treatment, showed substantial improvement in patients with a virological LTR to the combination treatment. In all nine patients biopsied at the 2-year follow-up, liver inflammation had disappeared totally (grade=0), and the stage (fibrosis) had improved. In contrast, no significant changes in grade or stage were noted in patients with a virological non-LTR to combination treatment. A significant improvement in inflammation was noted, in patients with a virological LTR, from 3.6 to 0.2 (P<0.01) and in fibrosis from 2.0 to 1.4 (P<0.05) whereas the corresponding scores for patients with a virological non-LTR did not change significantly, from 3.1 to 1.5 for inflammation and for fibrosis from 1.3 to 1.3. We conclude that patients with chronic hepatitis C who achieve a virological sustained response 6 months post-treatment with IFN-alpha2b and ribavirin will remain virological responders for a follow-up period of least 24 months, concomitant with a disappearance of inflammatory activity and a marked improvement of fibrosis in the liver.

Adult↗
PubMed1997

Therapy of hepatitis C: alpha interferon and ribavirin.

Ribavirin is a nucleoside analogue that has been evaluated as a therapy of chronic hepatitis C alone and in combination with alpha interferon. Ribavirin is well absorbed orally and is typically given in doses of 1,000 to 1,200 mg/d. Three randomized, placebo-controlled studies comprising more than 150 patients have shown that therapy with ribavirin alone for 24 to 48 weeks resulted in a significant reduction in serum alanine aminotransferase (ALT) levels during therapy. However, ribavirin therapy did not lead to a substantial reduction in hepatitis C virus (HCV) RNA levels; almost all patients remained viremic, and serum aminotransferase levels increased to pretreatment values when therapy was stopped. The most common adverse event was a moderate and reversible hemolysis during treatment that caused a decrease in hemoglobin by 10% to 20% of baseline levels. Combination therapy of ribavirin with alpha interferon has demonstrated promise both in pilot studies and a recently completed randomized controlled trial. Ribavirin in standard doses combined with alpha interferon in doses of 3 million units (MU) three times weekly for 6 months was found to significantly improve the sustained biochemical and virological response rates compared with interferon alone. Combination therapy offers a promise to become standard therapy for patients with nonsustained response to alpha interferon alone, because the majority of such patients achieve a durable response after treatment with combination therapy. However, nonresponders to alpha interferon alone rarely achieve a sustained beneficial response to combination treatment. For interferon-naive patients, combination therapy is superior to therapy with alpha interferon alone in achieving sustained biochemical and virological responses, but the combination demonstrates clear-cut superiority only in patients with unfavorable profiles for a response to interferon, in particular patients with high levels of HCV RNA. The optimal use and regimen of combination therapy awaits further investigation. New antiviral agents are still needed for the proportion of patients who do not respond to alpha interferon, even in combination with ribavirin.

Antiviral Agents↗
PubMed1997

Ribavirin enhances the efficacy but not the adverse effects of interferon in chronic hepatitis C. Meta-analysis of individual patient data from European centers.

BACKGROUND/AIMS: This study aimed to obtain a more precise estimation of the efficacy and tolerability of interferon-ribavirin combination therapy for chronic hepatitis C. METHODS: A meta-analysis was carried out of individual patient data comprising about 90% of the published experience with combination therapy. The study was set in four European university-affiliated liver referral centers. A total of 186 individuals with chronic hepatitis C who had participated in three randomized controlled trials and one open study were selected for the study. Fifty-one had received ribavirin monotherapy (1000-1200 mg/day), 37 interferon monotherapy (3 MU 3x/week) and 78 interferon-ribavirin combination therapy (dosage as for monotherapy) for 6 months. Twenty patients served as controls. Follow-up after therapy was 6 months. Data analysis was by the multivariate logistical regression method. RESULTS: The primary outcome measure for efficacy was the percentage with a sustained response (ALT normalization and HCV RNA negativity 6 months after therapy). The sustained response rate was significantly higher for interferon-ribavirin combination therapy than for interferon or ribavirin monotherapy (odds ratio IFN-Riba vs IFN = 9.8, 95% CI 1.9-50). The estimated probability of sustained response following interferon-ribavirin combination therapy was 51% for patients without previous IFN therapy, 52% for patients with previous IFN therapy and response-relapse, and 16% for previous IFN non-responders. No serious adverse events were observed and less than 10% withdrew. CONCLUSIONS: The efficacy of interferon-ribavirin therapy appears to be enhanced two- to threefold over interferon monotherapy in all major subgroups of chronic hepatitis C patients tested. In view of its acceptable toxicity profile, interferon-ribavirin combination therapy is a candidate for the new standard therapy for chronic hepatitis C.

Adult↗
PubMed1997

Interferon-alpha treatment induces delayed CD4 proliferative responses to the hepatitis C virus nonstructural protein 3 regardless of the outcome of therapy.

The proliferative responses to a hepatitis C virus (HCV) recombinant nonstructural protein 3 (rNS3) were analyzed in 9 patients with chronic HCV infection before, during, and after 24 weeks of treatment with interferon-alpha (IFN-alpha) alone or in combination with ribavirin. Regardless of the therapy and the subsequent outcome, all patients showed an increased rNS3-specific proliferative response in peripheral blood mononuclear cells in vitro within 48 weeks from the start of therapy (P < .01). The proliferating cell phenotype was CD4 and was dependent on HLA-DP/DQ/DR class II antigen presentation. rNS3 induced in vitro detectable interleukin (IL)-2, IL-10, and IFN-gamma production in some patients before or after therapy (or both). No significant differences existed between responders and relapsed responders plus nonresponders with respect to the NS3-specific CD4 T helper (Th) cell responses. Thus, IFN-alpha therapy induces HCV NS3-specific CD4 Th cell proliferation regardless of the outcome of therapy.

Adult↗
PubMed1995

Detection of hepatitis C virus RNA in the cell fraction of saliva before and after oral surgery.

The presence of hepatitis C virus (HCV) RNA in serum, whole saliva, and saliva from the submaxillary glands was investigated before and after oral surgery. The presence of HCV RNA (positive and negative-strand RNA) was determined in serum and saliva by a nested polymerase chain reaction in 26 anti-HCV positive patients, of whom 11 were coinfected with human immunodeficiency virus-1. Oral surgery was carried out on five occasions on four of the patients. HCV RNA was detected in the sera of 23 of 26 (88%) patients, and in the saliva of 4 of the 23 (17%) of the viremic patients. In all four cases, HCV RNA was detected only in the cell fraction derived from centrifugation of whole saliva. Negative-stranded HCV RNA was not detected. At one of five occasions of oral surgery, HCV RNA was detected in saliva sampled immediately after surgery, but not before or 24 hours after surgery. The results suggest that HCV is present in saliva in less than 25% of HCV viremic persons. The presence of the virus in saliva is restricted to the cell fraction. Thus, saliva may serve as a possible, but low, nonparenteral transmission route of HCV. Contamination of saliva by blood during and after oral surgery may result in an increased risk of viral exposure. Except for trauma caused by sharp instruments during surgery, this might contribute to the higher HCV seropositivity found among dentists.

Dentists↗
PubMed1995

Combined treatment with interferon alpha-2b and ribavirin for chronic hepatitis C in patients with a previous non-response or non-sustained response to interferon alone.

Ten patients with chronic hepatitis C, six of whom had not responded and four of whom had responded in a non-sustained fashion to interferon-alpha treatment alone, were given interferon alpha-2b and ribavirin in combination during 24 weeks. Interferon alpha-2b was given subcutaneously, at a dose of 3 MU thrice weekly, together with ribavirin orally, at a dose of 1,000-1,200 mg/day. All four patients with a prior non-sustained response to interferon alone had normal alanine aminotransferase (ALT) levels at the end of treatment as well as during follow-up (> or = 24 weeks post treatment). Furthermore, all four lost serum HCV-RNA at the end of treatment and three continued to be negative during follow-up. Among patients with a prior non-response to interferon alone three of six had normal ALT levels at the end of treatment and one at follow-up. Two of six became HCV-RNA negative at cessation of treatment, one of whom was negative also at follow-up. All former non-sustained responders and one of six non-responder patients thus showed a sustained biochemical response with eradication of HCV-RNA from serum in all cases but one. It is concluded that combination therapy with interferon alpha-2b and ribavirin offers a chance of sustained biochemical response with eradication of the viremia in patients who have not shown a persistent response to interferon-alpha alone.

Adult↗