Gilead Sciences Inc. /zigman2/quotes/210293917/composite GILD -1.38% said Thursday it has agreed to acquire MYR GmbH, a German biotech, for 1.15 billion euros ($1.39 billion) in cash, plus a potential future milestone payment of up to 300 million euros. The milestone payment will be made upon FDA approval of MYR's hepcludex, a treatment for chronic HDV infection in adults with compensated liver disease that has won conditional approval from the European Medicines Agency. HDV is the most severe form of viral hepatitis. "Hepcludex is a first-in-class treatment for HDV that blocks viral entry into liver cells through binding to NTCP," Gilead said in a statement. "It is the first and currently the only medicine conditionally approved for HDV by the EMA, and MYR anticipates submission for accelerated approval in the United States in the second half of 2021." The drug has both orphan drug and breakthrough therapy designations from the FDA. Gilead is expecting the deal to enhance revenue, be neutral to EPS in the first two years and then modestly accretive. Gilead shares were slightly higher premarket, but have fallen 6% in the year to date, while the SPDR S&P Biotech ETF /zigman2/quotes/205950134/composite XBI -2.15% has gained 44% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.53% has gained 13.7%.