Key Takeaways MRK faces major headwinds as Keytruda, its top revenue driver, nears the loss of exclusivity in 2028.Declining Gardasil sales due to weak China demand and lower vaccine uptake in Japan ail MRK.MRK is counting on Capvaxive, Winrevair and strategic cost savings to help counter patent/pricing headwinds.Merck (MRK) is expected to face some notable headwinds over the next few years that could affect its long-term growth outlook, the most significant being the upcoming loss of exclusivity (“LOE”) fo ...