Merck Stock's Ticking Keytruda Time Bomb

Core Viewpoint - Merck's growth is heavily reliant on Keytruda, which poses risks as competition increases and patent expiration approaches [1][3][9] Sales Performance - Keytruda's sales surged 72% from $17 billion in 2021 to $29 billion in 2022, constituting 46% of Merck's total revenues [2][9] - The drug has been the primary driver of Merck's double-digit revenue growth over the past three years [2] Patent Expiration and Competition - Keytruda's U.S. market exclusivity is set to end in 2028, leading to anticipated biosimilar competition [3][4] - Sales are projected to peak at around $36 billion by 2028, with potential declines to $20 billion or below in the following years [3][5] Impact of Biosimilars - Historical examples show that sales can drop sharply with the entry of biosimilars, as seen with AbbVie's Humira and Roche's Herceptin [4] - Humira's sales fell nearly 60% from $21 billion in 2022 to under $9 billion, illustrating the disruptive nature of biosimilar competition [4] Future Growth Challenges - Merck is unlikely to maintain sales growth as Keytruda's sales are expected to decline significantly [5][6] - The company must find new revenue streams within the next three years to avoid slower or falling sales [7][9] Investment Implications - The situation highlights the need for a diversified investment portfolio to manage concentrated risks associated with reliance on a single product [10] - Merck's dependency on Keytruda represents both a current strength and a significant vulnerability for future growth [9][10]