The manufacture of vaccines and therapeutic proteins has suffered from a reputation of being part art and part science, with heavy doses of regulatory uncertainty thrown in. Postapproval changes (PACs) to chemistry, manufacturing, and controls (CMC) were initiated reluctantly and carefully in the era of “the process is the product.” Today, CMC PACs are a normal part of the biopharmaceutical industry business. Emma Ramnarine (head of global biologics quality control at Hoffmann-La Roche in South San Francisco, CA) notes that…