In Cambridge, MA, scientists at Mersana keep quality by design (QbD) in mind from the start when creating an antibody-drug conjugate (ADC). These combinations of an antibody and one or more drugs—as many as 10 in some of Mersana’s ADCs—can create complicated challenges in bioprocessing.

In discussing Mersana’s multi-drug ADC platform called Dolaflexin, chief manufacturing officer Michael Kaufman, PhD, explains that the complexity requires QbD.

Michael Kaufman, PhD

“When you have hundreds of unit operations and thousands of parameters, you need to use a QbD approach—otherwise you would spend forever trying to develop a process,” he says. “We’ve embedded QbD very early in the process development.”

In particular, he notes that QbD really improves some steps. One of them is risk assessment. For example, with thousands of parameters involved in the development of an ADC, it’s hard to know which ones will impact safety or efficacy of the therapeutic. “With QbD, we have the thousands of parameters down to a workable assessment of which ones we really have to focus on,” Kaufman explains.

Also, scientists at Mersana use QbD with scaled-down models. “You can’t possibly do, every experiment you want, because you would be using so many raw materials and it would take forever,” Kaufman says. “But if you’re going to develop a scaled-down model, I think the logical questions are: How good is your model? Does it predict what you get when you scale up?”

Here again, Mersana turns to QbD in developing these models. “The art of developing the scaled-down models is doing the right experiments to convincingly show to both scientists and regulators that the predictions from the scaled-down models are applicable to the scaled-up situation,” he points out.

Last, Kaufman mentions experiments that can simultaneously analyze more than one parameter. After performing those experiments, Mersana’s scientists “use model building to really look at what the results are by applying QbD,” Kaufman explains.

To improve the overall quality of an ADC, Mersana uses QbD wherever it provides a useful return, and that occurs in many parts of bioprocessing.