The Price We Pay to Conduct Ethical Trials for Efficacy

• Activity Number: 178
• Type: Contributed
• Date/Time: Monday, August 1, 2011 : 10:30 AM to 12:20 PM
• Sponsor: Biopharmaceutical Section
• Author(s): Charlie Goldsmith*+
• Companies: Simon Fraser University
• Keywords: factorial design ; partial factorial design ; efficacy ; efficiency ; ethics ; patients

Abstract

Previous work has shown a partial factorial design that eliminates those treatment combinations of unknown efficacy, such as in a trial of a new therapy where the clinical condition has at least two already proven therapies that are used alone or in combination. Such partial designs use fewer treatment combinations but all provide patients with therapy of known efficacy. Partial designs allow efficacy estimation of the unproven therapy, provided this new therapy does not interact with the other therapies. Relative to a full factorial design of 3 therapies at 2 levels in a 3 replicate 2**3 = 8 treatment combination design with 24 patients randomized, the partial factorial design with 6 treatment combinations eliminating the placebo group and the new therapy group, using 4 replicates with 24 patients, estimates new therapy efficacy with 80% efficiency because of 3 new therapy treatment effect replicates, rather than the 4 provided by the full factorial design. Partial designs allow for new therapy efficacy estimation when the other therapies are additive, synergistic or antagonistic, as long as the new therapy does not interact with the proven therapies.