AimsThe primary objective of this study was to determine whether pharmacokinetic interactions occurred between interferon a-2b (IFN) and ribavirin in patients with chronic hepatitis C infections. Additionally this study assessed the single and multiple-dose pharmacokinetics of ribavirin and IFN, and compared the safety, tolerability and antiviral pharmacodynamics of IFN plus ribavirin compared with either drug alone.Methods In this open label parallel group study, patients with chronic hepatitis C were randomized to receive IFN 3 million IU thrice weekly s.c. alone, ribavirin 600 mg twice daily p.o. alone or both drugs in combination over 6 weeks. Single and multiple dose pharmacokinetics and indices of antiviral pharmacodynamics were assessed during weeks 1 and 6, along with safety assessments during the study. Results The range of mean ribavirin terminal phase half-lives after single doses was 44-49 h. Comparison of week 1 and week 6 AUC(0,12h) values showed accumulation in plasma of approximately 6-fold. The range of mean washout halflives after week 6 was 274-298 h, reflecting release of ribavirin from deep compartment stores. The range of single and multiple dose IFN terminal phase halflives was 5-7 h. IFN demonstrated an increase in bioavailability (~2-fold) upon multiple dose administration. Ribavirin and IFN pharmacokinetic parameters for combined ribavirin and IFN were similar to those during monotherapy with either compound, although the power of this study to detect differences was low. Serum HCV-RNA titers and ALT concentrations were reduced by IFN alone, ribavirin alone reduced ALT concentrations only, and combined IFN plus ribavirin produced numerically greater falls in both measurements than either treatment alone. Serum concentrations of neopterin and activity of 2∞,5∞-oligoadenylate synthetase (2∞5∞-OAS) were increased by IFN alone and in combination with ribavirin, whereas serum 2∞5∞-OAS activity was decreased and neopterin concentrations unaltered by ribavirin monotherapy. IFN and ribavirin monotherapy produced characteristic changes in safety laboratory tests (IFN-reductions in white cells, neutrophils and platelets; ribavirin-reduced haemoglobin) and characteristic adverse event profiles (IFN-headache, flu-like symptoms, fatigue, anorexia, nausea, myalgia, and insomnia; ribavirin-headache, fatigue, myalgia, and pruritus). There was no additive effect of combination therapy on safety laboratory tests or reported adverse events. All changes were fully reversible upon treatment cessation. Conclusions There was no evidence of pharmacokinetic interactions between IFN and ribavirin in this study. There were numerical trends indicating that the combination of IFN and ribavirin reduced titers of HCV-RNA to a greater extent than did either treatment alone, and the safety profile of combination therapy was similar to those of both monotherapy treatments.
Limited additional benefit was gained from being in the group receiving the intensive health care advice. It is difficult to make an important impact on cardiovascular risk in primary care by using only the practice staff. Better methods of communicating the messages need to be devised.
SummaryThis open-label multi-centre study evaluated a new intravenous immunoglobulin, Gammaplex®, in the treatment of 50 patients with primary immunodeficiency and significant hypogammglobulinaemia. Patients treated previously with other intravenous immunoglobulins received Gammaplex® on their same infusion schedule for 1 year; 22 were on a 21-day and 28 on a 28-day regimen (300-800 mg/kg/infusion). There were no serious, acute bacterial infections, whereas six subjects (12·0%) had at least one such infection in the 6 months before enrolment. Forty subjects (80·0%) had at least one non-serious infection; the median number of infective episodes per subject per year was 3·07. Antibiotics were taken by 38 subjects therapeutically and prophylactically by 16 at some time. Fewer than half (46·0%) missed any time off work or school because of infection or other illness. Trough immunoglobulin (Ig)G levels were above 6·00 g/l in all subjects at all assessments after 15 weeks with two exceptions. Overall, 21·2% of infusions were associated with an adverse event up to 72 h after infusion. The frequency of adverse events increased with infusion rate. Headache was the most common product-related adverse event (7·5% of 703 infusions). In conclusion, Gammaplex® is effective in primary immunodeficiency and is well tolerated.
Background and ObjectivesThis multicentre, open-label study investigated the safety and efficacy of Gammaplex, a 5% Intravenous Immunoglobulin (IVIg), in patients with idiopathic (immune) thrombocytopenic purpura (ITP).Materials and MethodsPatients were between the ages of 6 and 70 years; had ITP for at least six months and had a platelet count ≤20×109/L. Eligible patients were dosed with 1 g/kg of Gammaplex on two consecutive days, followed by assessment of safety and efficacy on Days 3, 5, 9, 14, 21, 32 and 90. Response was defined as the increase in platelet count to a threshold of ≥50×109/L on or before Day 9 after the first dose of Gammaplex.ResultsAll 35 patients received at least one infusion of Gammaplex. Twenty-nine (83%) patients responded to Gammaplex, similar to the historical control, with a 95% lower one-sided confidence interval of 68.9%. Median duration of response was 10.0 days, with an overall reduction in bleeding episodes. Gammaplex provided supranormal concentrations of total IgG; mean peak concentration (Cmax) of 45.3 g/L (4.53 g/dL), with a mean half-life of 28.5 days. Fifteen patients reported 63 Adverse Drug Reactions (ADRs); the most common were headache (10 patients), vomiting (6 patients) and pyrexia (5 patients). Five of these ADRs were considered serious, one patient had three concurrent Serious Adverse Events (SAEs); these were vomiting, dehydration and headache. Two other patients each had one SAE (headache). There were no unexpected Adverse Events (AEs) or thromboembolic episodes and no significant changes in vital signs, biochemical, haematological and virology results. Conclusion: Gammaplex achieved a very high concentration of serum IgG but was well-tolerated and effective in the treatment of ITP with a similar degree of efficacy to the pre-determined historical control group and the pre-set statistical criteria.Trial RegistrationClinicalTrials.gov NCT00504075 Clinical Trials Registry India 000016
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