Optum — Previously we have outlined how the “patent cliff” in the years since 2012 curtailed profits for drug makers, and sent them searching for more reliable sources of revenue. In large part, this has increasingly turned them toward the promise of biologic drugs: Currently in the U.S., there are over 900 biologically engineered drugs in development, while worldwide sales of biologics are expected to grow to nearly half of the top-100 selling drugs in just the next two years.