US Stock Market Move | Biotech sector broadly declines; Merck & Co., Inc. (MRK.US) falls over 2%.

On Thursday, the biotech sector broadly declined, with Eli Lilly (LLY.US) falling over 3%, Merck & Co., Inc. (MRK.US) dropping more than 2%, Johnson & Johnson (JNJ.US) down 2%, and Novo Nordisk A/S Sponsored ADR Class B (NVO.US) and AbbVie (ABBV.US) each declining over 1%. Recently, clinical-stage vaccine company Vaxcyte announced key Phase III trial results for its adult 31-valent pneumococcal conjugate vaccine VAX-31, a development that swayed sentiment across the entire pharmaceutical sector. The clinical data showed that VAX-31 has a favorable safety profile and met the non-inferiority standard for serotypes covered by the existing mainstream 20-valent and 21-valent vaccines. The company plans to submit a marketing application to the FDA in the first half of 2028. Although there is still a long path to commercialization, the capital markets have already viewed this high-valent vaccine as an important signal of a reshaping of the pneumococcal vaccine landscape. Amid this transmission of market sentiment, industry leader Merck & Co., Inc. has drawn significant attention. Merck & Co., Inc. holds an already commercialized 21-valent pneumococcal vaccine and is a core player in the global adult pneumococcal vaccine space. VAX-31 raises serotype coverage to 31 types, leading the market to anticipate that if subsequent approvals proceed smoothly and commercialization is well executed, the new product could exert direct competitive pressure on Merck & Co., Inc.'s existing flagship product.