What Happens To Merck Stock If Keytruda Sales Stop Growing?

Shares of Merck (MRK) returned 76.2% over the past year, compared with 17.4% for the S&P 500. U.S. growth for the company's cancer drug Keytruda is set to slow. Management said on the August 4 call that U.S. Keytruda growth will moderate as the drug reaches peak penetration across several key indications. Barron's also reported on October 7 that a Dutch court barred Merck from selling subcutaneous Keytruda in eight European markets. So how much of what Merck sells is Keytruda.