Design of Experiment
Hanuman Mallubhotla, Ph.D., research director for biopharmaceutical development at Syngene International, has achieved excellent results in work to improve antibody protein production through a statistical design-of-experiment (DoE) approach in mammalian cell fed-batch processes.
Dr. Mallubhotla applied this strategy using JMP, a statistical software package available from SAS Institute, to evaluate 15 basal and 7 feed media while controlling for feed rate and temperature. He optimized media and feed based on statistically observed interactions and amino acid/metabolite profiles. The result was a titer increase from 0.5 g/L in shake flasks to more than 3.0 g/L in bioreactors. Investigators collected samples and analyzed for glucose, lactate, titer, and amino acid content.
“Optimization of the cell culture processes usually happens as an afterthought,” Dr. Mallubhotla observes. “Most companies are under severe pressure to produce the material under aggressive deadlines. We accomplished a step-by-step DOE methodology to optimize the cell culture process before going into manufacturing.”
Organizations that build this methodology into its standard development plans will be capable of developing a cell culture processes for antibodies and perhaps for other molecules, quickly and predictably, Dr. Mallubhotla adds. “It will be like an assembly line.”
Companies have attempted to reach platform development processes, but each requires revision and rework to accommodate molecular differences. Through this process—perhaps system is a better term—Syngene provides its customers with clinical and commercial material while shortening time-to-market. “We are talking about a principle that can applied to many situations, as opposed to an application platform itself,” Dr. Mallubhotla says.
A good deal has been discussed regarding scaledown methods involving small, parallel bioreactors. In April 2014, contract manufacturer Gallus Pharmaceuticals officially adopted the ambr15™ microbioreactor from TAP Biosystems, a Sartorius Stedim Biotech business unit.
“We use the ambr15 to perform many types of screening and response surface designs,” says Matthew Zustiak, Ph.D., principal scientist, cell culture development, Gallus. Optimizations include media and feed screening, feed strategy optimization, feed timing, feed quantity, and process parameters such as pH and temperature.
According to Dr. Zustiak, ambr’s main strength is its ability to run a 48-vessel, fed-batch study that closely mimics conditions inside a larger-scale bioreactor, and to perform large studies examining multiple process variables in a single device. “The ambr excels at individual control of the feed supplementation or pH control strategy since each vessel has independent control.”