This understading would help define critical quality attributes as the biotech industry begins its discussion toward incorporating the principles of quality by design (QbD), taking cues from the lessons learned in small-molecule production. As the meeting progressed, however, the talk in the halls and in meeting rooms focused on a major obstacle: How does industry link molecular structure and other attributes with biology and therapeutic effect?
The behavior of a biologic can be difficult to explain, let alone predict. One hot-topic problem discussed was the presence of agglomerates, particulates, and subvisible particles in a formulation. These particles may (and may not) cause opalescense and phase separation, but so too could mechanical stress, temperature, and pH, as Mary Cromwell (Genentech) explained. Whether, then, immunogenicity is altered is a huge question. For now, until science bridges the gaps, we must settle for Wim Jiscoot's (Leiden University) reply: "We simply don't know."Maribel Rios is a senior editor of Pharmaceutical Technology.