Subgroup analysis often is used to show positive results from a trial that failed to meet its primary end point in a broad patient population. However, subsequent trials done in the subgroup don't always confirm the subgroup analysis from the larger trial.

Alpha-Beta Technology Inc. believes that its case will be one of the successful exceptions, because the subgroup was prospectively identified in the first trial. ABTI (Worcester, Mass.) last week said it will conduct a second Phase III trial of its Betafectin PGG-glucan to prevent post-operative infections. The trial will focus on non-colorectal gastrointestinal surgeries.