- Merck & Co. on Monday disclosed the first late-stage results for its experimental pneumococcal conjugate vaccine, presenting initial data from two Phase 3 studies in adults living with HIV and in older adults.
- In the trial involving adults with HIV, inoculation spurred immune responses across all 15 strains of the bacteria Streptococcus pneumoniae against which Merck's vaccine, dubbed V114, is designed to protect. The second study showed concomitant immunization with V114 and a quadrivalent influenza vaccine was safe and similarly protective as separate administration of the two vaccines.
- V114 is Merck's answer to Pfizer's market-leading pneumococcal conjugate vaccine, Prevnar 13, which earned nearly $5.9 billion in sales last year. Monday's data are the first to emerge for a slate of 16 Phase 3 studies Merck is conducting, and could help support a submission for U.S. approval this year or next.
Monday's results are a positive step for Merck's development for V114, but they aren't the critical test of whether the vaccine can challenge Prevnar 13, or compete with a successor candidate Pfizer is developing. That will come with two larger Phase 3 trials that completed in late March and early April.
Instead, the data Merck announced Monday help to answer two specific questions: whether vaccination with V114 would be safe and immunogenic in adults with HIV, and whether the vaccine could be safely given alongside an approved influenza vaccine.
People living with HIV are at higher risk of pneumococcal disease, and pneumococcal pneumonia is a known risk following influenza infection.
V114 is what's known as a conjugate vaccine, pairing an antigen with a protein that helps boost the body's immune response. Pfizer's Prevnar 13 is also a conjugate vaccine and helps protect against the 13 types of pneumococcal bacteria that most commonly cause infection.
With V114, Merck would add two more, known as serotypes 22F and 33F, that aren't contained in Prevnar 13 and are an emerging cause of pneumococcal infection.
Merck sells another type of pneumococcal vaccine that protects against 23 serotypes, and is currently recommended in the U.S. to be given following vaccination with Prevnar 13.
Success with V114 matters greatly to Merck, which has become increasingly dependent on sales of its cancer immunotherapy Keytruda and its HPV vaccine Gardasil. Pneumovax 23, Merck's marketed pneumococcal vaccine, earns about one-sixth of what Pfizer makes off of Prevnar 13.
Pfizer is also developing a third-generation pneumococcal conjugate vaccine that's designed to protect against 20 serotypes. The drugmaker has announced positive results from two Phase 3 trials, but hasn't yet disclosed detailed data.
Pfizer plans to soon ask the Food and Drug Administration for approval, potentially increasing the competitive challenge for Merck.
Rather than include higher numbers of serotypes in its new vaccine, Merck's strategy is more targeted, focusing on adding serotypes 22F and 33F without comprising immunogenicity for the serotypes Prevnar 13 protects against.
Merck could also obtain results for V114 in children and adolescents sooner than Pfizer, according to Cantor Fitzgerald analyst Louise Chen, who estimated in a note to clients that Merck is one to two years ahead of its competitor. On Monday, Pfizer announced the start of two studies of its 20-valent vaccine in infants.
In addition to V114, Merck is developing two other conjugate vaccines for adult and pediatric populations.