DOE factors into bioassay development, says USP workshop.

ROCKVILLE, MD -- Among the biotechnology industry, Design of Experiments (DOE) principles are used to facilitate safe and effective product development. A DOE-based program can benefit biotech teams early on, as they build development programs for biological assays, and at the qualification and validation stages, when the impact of assay conditions on test results is crucial.

Stanley Deming, Ph.D., president of Statistical Designs in Houston, TX, told USP's Bioassay Workshop that he encourages scientists to pay attention to fundamental data before jumping into the experiment design. "DOE will change your way of thinking," he said. "Maybe things aren't the way you thought they were."

Understanding bioassay goals and keeping them practical will help manage time, costs and expectations. Preparation is essential when budgeting for bioassays, Deming said, which can quickly become expensive. "If you want to save money on the bioassay, you need to begin with some expensive factors and some cheap factors," he recommends.

In general, including as many potentially important factors as possible during the screening process is key.

Once a reliable bioassay has been developed, researchers must monitor and statistically evaluate the assay. A process control chart is one way to do this.

Deming reminds study leaders not to focus only on the obvious criticalities and interferences in chart results, but to also "look at the good points and see what you can make of them."

Above all else, scientists should effectively analyze and apply the results of their assays. "One of the big concerns I have with bioassays is people will use control limit assays for specifications," Deming said. "Problems or specifications developed that way might be narrower, or those specifications might not have been tight enough. Specifications should always be based on fitness for use."

Understanding the reasons for study results, whether favorable or not, gives biotechs more insight into the product and process. "A lot of people will do [broad] experiments, simply because they can't believe their study gave the results it did," Deming said. Bioassays help researchers to progress from a situation with potentially unknown interactions and events to a position where they are aware of exactly what's occurring with their product and why.

Carrie Nathans, Managing Editor