MRK's Winrevair Phase III Study in Newly Diagnosed PAH Meets Goal

Core Insights - Merck's phase III HYPERION study for its PAH drug Winrevair (sotatercept) met its primary endpoint, demonstrating significant efficacy in reducing clinical worsening in newly diagnosed PAH patients [2][9]. Study Details - The HYPERION study compared Winrevair to placebo in adult patients with WHO Group 1 functional class II or III PAH at intermediate or high risk of disease progression, with the primary endpoint being time to clinical worsening (TTCW) [3][4]. - The study was stopped early due to overwhelming efficacy observed in the ZENITH study and other data, marking HYPERION as the third successful phase III study for Winrevair [5][9]. Financial Performance - Winrevair generated sales of $280 million in Q1 2025, reflecting a 40% sequential growth, supported by strong prescription trends in the U.S. [9][12]. - Merck is relying on Winrevair to enhance its revenue stream as its blockbuster drug Keytruda is expected to lose patent exclusivity in 2028 [13]. Competitive Landscape - Major competitors in the PAH market include United Therapeutics and Johnson & Johnson, with UTHR's PAH drugs generating significant sales in Q1 2025 [14][15]. - UTHR reported sales of $138.2 million for Remodulin, $120.7 million for Orenitram, and $466.3 million for Tyvaso, while J&J's PAH franchise generated $1.02 billion in revenue [15].