RESUMEN
During the past decade, there has been increasing interest in adaptive clinical trials in pharmaceutical drug development as a means to improved decision making, better dose selection, and reduction in cost and time to market. Nevertheless, the operational challenge of drug supply continues to be a barrier preventing greater uptake of adaptive designs. Such studies require the ability to quickly accommodate changes in treatment allocation while maintaining the integrity of the blind. The DIA Adaptive Design Scientific Working Group formed a subteam to discuss solutions to the drug supply dilemma. In this paper, the subteam discusses effective strategies for drug manufacturing, labeling, packaging, and randomization and addresses financial concerns.
RESUMEN
BACKGROUND AND AIMS: This study assessed the efficacy and safety of up to 4 years of lamivudine treatment and the clinical relevance of the emergence of YMDD-variant hepatitis B virus (HBV). METHODS: Fifty-eight Chinese adult patients with chronic hepatitis B (CHB) were randomized to lamivudine 100 mg/day for up to 5 years and were monitored for YMDD-variant HBV, hepatitis B e antigen (HBeAg) seroconversion (loss of HBeAg and detectable antibody to HBeAg) and serum alanine aminotransferase (ALT) concentrations. Four-year data are reported here. RESULTS: The rate of HBeAg seroconversion increased with extended therapy and also with higher baseline ALT concentrations. YMDD-variant HBV was detected in 67% (39/58) of patients at some point during treatment. After 4 years, a total of 47% (27/58) of patients achieved HBeAg seroconversion. Thirty-three per cent (13/39) of patients with YMDD-variant HBV achieved HBeAg seroconversion; this increased to 57% (8/14) in patients with moderately elevated (>2-5 x upper limit of normal) pre-treatment ALT concentrations. The proportion of patients that achieved normal serum ALT increased from 29% (17/58) at baseline to 69% (31/45) following 4 years of treatment. That included 68% (23/34) of patients with YMDD-variant HBV and 73% (8/11) of those without the variant. All patients receiving lamivudine had reduced serum concentrations of HBV-DNA compared with baseline, despite the emergence of YMDD-variant HBV in 39 patients. Lamivudine was generally well tolerated; there was little change in the number or type of drug-related adverse events in the fourth year of the study. CONCLUSIONS: Despite the emergence of YMDD-variant HBV, Chinese patients showed increased HBeAg seroconversion and improvement in ALT levels with an increased duration of treatment with lamivudine.