HONG KONG - With a corporate valuation of $1.04 billion, the South Korean biosimilar company Aprogen Inc. has become the country’s first biotech “unicorn,” according to U.S. market research firm CB Insights. Korea now ranks fifth, tied with Germany, in terms of the number of unicorns, with total of 11 unicorns, a term used to describe private ventures with $1 billion-plus valuations.