London's status as a leading centre for the life sciences, financial and digital industries has attracted significant new investment by two leading US companies, announced today as Mayor of London Boris Johnson visited Boston as part of a trade delegation to the East Coast of the USA. Gilead Sciences, a Fortune 500 US biotechnology company, is deepening its UK presence with a new commercial HQ in the heart of London from which to grow the company's portfolio, which includes treatments for HIV/Aids, liver diseases, serious respiratory and cardiovascular diseases and cancer.