European Commission (EC) Approves Merck's CAPVAXIVE® (Pneumococcal 21-valent Conjugate Vaccine) for Prevention of Invasive Pneumococcal Disease and Pneumococcal Pneumonia in Adults

EC decision marks the fourth approval for CAPVAXIVE for pneumococcal vaccination in adults

Merck (NYSE:MRK), known as MSD outside of the United States and Canada, announced today that the European Commission (EC) has approved CAPVAXIVE^® (Pneumococcal 21-valent Conjugate Vaccine) for active immunization for the prevention of invasive disease and pneumonia caused by Streptococcus pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15B, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B in individuals 18 years of age and older. CAPVAXIVE is a pneumococcal vaccine specifically designed to help protect adults from the serotypes responsible for the majority of invasive pneumococcal disease (IPD) cases. The EC approval of CAPVAXIVE is based on safety and immunogenicity data from the Phase 3 STRIDE clinical program.

This decision authorizes the marketing of CAPVAXIVE in all 27 European Union (EU) member states, as well as Iceland, Liechtenstein and Norway. The timing for availability of CAPVAXIVE in individual countries will depend on multiple factors, including the completion of reimbursement procedures. CAPVAXIVE was approved in the U.S. in June 2024, in Canada in July 2024, and in Australia in January 2025.

"Pneumococcal disease continues to pose a significant risk for adults in Europe, among adults who are 65 or older, and also among younger adults who are immunocompromised or have chronic medical conditions," said Dr. Lina Pérez Breva, Vaccine Research, Fisabio - Public Health, Valencia, Spain. "Based on data from the Phase 3 STRIDE clinical program, CAPVAXIVE offers coverage against the serotypes responsible for the majority of invasive disease cases in adults, making this approval in the EU an important step in helping to protect adults from pneumococcal disease."

"By focusing on the serotypes that have been responsible for an increasing proportion of adult invasive pneumococcal disease cases, CAPVAXIVE allows us to offer protection specifically designed for adults," said Dr. Paula Annunziato, senior vice president, infectious diseases and vaccines, Global Clinical Development, Merck Research Laboratories. "We are proud to bring CAPVAXIVE to adults in Europe who may benefit from its broad protection and are eager to continue working with regulatory authorities to expand CAPVAXIVE availability worldwide."

European Union country-level data have demonstrated that the serotypes covered by CAPVAXIVE are responsible for more cases of IPD in adults compared to PCV20 (pneumococcal 20-valent conjugate vaccine), as shown in these selected four countries:

Data were included for select countries based on EU membership, population size and the most recent year reported. These values are based on country-level epidemiologic data and regional variations may exist; they do not reflect the efficacy of the respective vaccines. There are currently no studies comparing the efficacy of CAPVAXIVE and PCV20.

The decision by the EC follows the positive recommendation from the European Medicines Agency's Committee for Medicinal Products for Human Use released in January 2025 and was based on results from the pivotal Phase 3 STRIDE-3 trial (NCT05425732), which evaluated CAPVAXIVE compared to PCV20 in adults 18 years of age and older who had not previously received a pneumococcal vaccine, and STRIDE-10 (NCT05569954), which compared CAPVAXIVE to PPSV23 (pneumococcal vaccine, polyvalent [23-valent]) in adults 50 years of age and older who had not previously received a pneumococcal vaccine. The approval is also supported by results from the Phase 3 STRIDE-4 (NCT05464420), STRIDE-5 (NCT05526716), STRIDE-6 (NCT05420961), and STRIDE-7 (NCT05393037) trials (see "Clinical data supporting EC approval" below, for additional details).

Clinical data supporting EC approval

CAPVAXIVE was approved by the EC based on data that included Phase 3 clinical studies designed to evaluate its safety and immunogenicity in a variety of adult populations. These included:

• STRIDE-3 (NCT05425732): A double-blind, Phase 3 study which evaluated CAPVAXIVE compared to PCV20 in individuals 18 years of age and older who had not previously received a pneumococcal vaccine. Participants 50 years of age and older were enrolled in cohort 1 (n=2,362), and participants 18 through 49 years of age were enrolled in cohort 2 (n=300). Participants were randomized to receive a single dose of either CAPVAXIVE or PCV20. Results from the study include:
  • In adults 50 years of age and older (cohort 1), CAPVAXIVE was non-inferior to PCV20 for the 10 serotypes shared with both vaccines (3, 6A, 7F, 8, 10A, 11A, 12F, 19A, 22F, 33F), as assessed by serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) one month post-vaccination;
    • CAPVAXIVE was superior to PCV20 for 10 of 11 serotypes included in CAPVAXIVE but not in PCV20 (9N, 15A, 16F, 17F, 20A, 23A, 23B, 24F, 31, 35B), as assessed by serotype-specific OPA GMTs one month post-vaccination and the proportions of patients with a greater than or equal to four-fold increase in OPA from pre-vaccination to one month post-vaccination;
    • Immune responses were observed for serotype 15C in participants receiving CAPVAXIVE but did not meet criteria for statistical superiority;
  • In individuals 18 through 49 years of age (cohort 2), CAPVAXIVE elicited non-inferior immune responses (immunobridged) compared to individuals 50 through 64 years of age, as assessed by serotype-specific OPA GMTs one month post-vaccination;
  • Across both cohorts, CAPVAXIVE had a safety profile comparable to PCV20.
• STRIDE-10 (NCT05569954): A randomized, double-blind, Phase 3 study which evaluated CAPVAXIVE compared to PPSV23 in individuals 50 years of age or older who had not previously received a pneumococcal conjugate vaccine (n=1,484). Results from the study include:
  • CAPVAXIVE was non-inferior to PPSV23 for the 12 common serotypes and was superior to PPSV23 for the nine unique serotypes in CAPVAXIVE, as measured by serotype-specific OPA GMTs 30 days post-vaccination;
  • The proportion of patients with ≥4-fold rise in OPA GMT ratios from Day 1 to Day 30 for serotype-specific OPA for V116 was superior to PPSV23 for eight out of nine serotypes unique to CAPVAXIVE compared to PPSV23;
  • CAPVAXIVE was found to have a safety profile comparable to PPSV23.
• STRIDE-4 (NCT05464420): A randomized, double-blind, Phase 3 lot-to-lot consistency study which evaluated CAPVAXIVE in individuals 18 to 49 years of age who had not previously received a pneumococcal conjugate vaccine (n=2,162). Participants were randomized to receive a single dose of either one of three lots of CAPVAXIVE or PPSV23 (pneumococcal 23-valent polysaccharide vaccine). Results from the study include:
  • Across the three lots, CAPVAXIVE elicited equivalent immune response, as assessed by serotype-specific OPA GMTs and Immunoglobulin G (IgG) geometric mean concentrations (GMCs) 30 days post-vaccination;
  • OPA GMTs were generally comparable between CAPVAXIVE combined lots and PPSV23 groups for the common serotypes and were higher in the CAPVAXIVE group for serotypes unique to CAPVAXIVE;
  • CAPVAXIVE has a safety profile comparable to PPSV23.
• STRIDE-5 (NCT05526716): A randomized, double-blind, Phase 3 study which evaluated CAPVAXIVE when administered concomitantly or sequentially (30 days later) with QIV in adults 50 years of age and older (n=1,080). Results from the study include:
  • For the primary immunogenicity endpoints, CAPVAXIVE administered concomitantly with QIV was non-inferior to CAPVAXIVE administered sequentially with QIV for 20 of 21 serotypes in CAPVAXIVE (as assessed by OPA GMTs at one month post-vaccination), as well as for three of four influenza strains in QIV (as assessed by hemagglutination inhibition (HAI) GMTs at one month post-vaccination);
  • The rates and severity of solicited systemic adverse reactions and solicited local adverse reactions at the CAPVAXIVE injection site were similar when CAPVAXIVE was administered with or without inactivated QIV.
• STRIDE-6 (NCT05420961): A randomized descriptive Phase 3 study which evaluated CAPVAXIVE in individuals 50 years of age and older who had previously received a pneumococcal vaccine at least one year before enrollment. Participants were enrolled into one of three cohorts based on their previous pneumococcal vaccination history (cohort 1: PPSV23, cohort 2: PCV13 [pneumococcal 13-valent conjugate vaccine], or cohort 3: PPSV23 followed by or preceded by PCV13, PPSV23 preceded by PCV15 [pneumococcal 15-valent conjugate vaccine], or PCV15 alone). Participants in cohort 1 were randomized to receive CAPVAXIVE (n=231) or PCV15 (n=119), participants in cohort 2 were randomized to receive CAPVAXIVE (n=176) or PPSV23 (n=85), and participants in cohort 3 were allocated to receive CAPVAXIVE (n=106). In each of the 3 cohorts, serotype-specific OPA GMTs and the proportion of individuals with ≥4-fold rise in OPA responses from baseline to one-month post-vaccination were assessed. Results from the study include:
  • In cohort 1, CAPVAXIVE elicited OPA responses that were comparable to PCV15 for the 6 common serotypes, and higher for the 15 unique serotypes and serotype 15B;
  • In cohort 2, CAPVAXIVE elicited OPA responses comparable to PPSV23 for the 12 common serotypes and serotype 15B, and higher for the 9 unique serotypes;
  • OPA responses to CAPVAXIVE were similar across the 3 cohorts of participants who previously received one or more pneumococcal vaccines;
  • CAPVAXIVE had a safety profile comparable to both PCV15 and PPSV23.
• STRIDE-7 (NCT05393037): A randomized, double-blind, Phase 3 study which evaluated CAPVAXIVE in individuals 18 years of age or older living with human immunodeficiency virus (HIV) (n=304) who were pneumococcal vaccine-naïve or vaccine-experienced prior to the study. Participants were randomized to receive either CAPVAXIVE or PCV15 + PPSV23. Results from the study include:
  • CAPVAXIVE was immunogenic for all serotypes covered by the vaccine, as assessed by OPA GMTs and IgG GMCs 30 days post-vaccination;
  • CAPVAXIVE elicited comparable immune responses to PCV15+PPSV23 for all 13 shared serotypes and higher immune responses for the eight serotypes covered only by CAPVAXIVE, as assessed by serotype-specific OPA GMTs and IgG GMCs at Day 30;
  • Fewer participants experienced adverse events (AEs) with CAPVAXIVE (71.6%) compared with PCV15+PPSV23 (91%), primarily due to fewer injection-site AEs.

About CAPVAXIVE

CAPVAXIVE is Merck's FDA-approved 21-valent pneumococcal conjugate vaccine indicated for active immunization for the prevention of invasive disease and pneumonia in adults 18 years of age and older. CAPVAXIVE is specifically designed to help address Streptococcus pneumoniae serotypes predominantly responsible for adult invasive pneumococcal disease (IPD), including eight unique serotypes, 15A, 15C, 16F, 23A, 23B, 24F, 31 and 35B compared to other pneumococcal vaccines. CAPVAXIVE is administered as a single dose.

CAPVAXIVE Indication in the U.S.

CAPVAXIVE is indicated in the U.S. for:

• Active immunization for the prevention of invasive disease and pneumonia caused by Streptococcus pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15B, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B in individuals 18 years of age and older;
• Active immunization for the prevention of pneumonia caused by S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B in individuals 18 years of age and older.

CAPVAXIVE should not be administered to individuals with a history of a severe allergic reaction (e.g., anaphylaxis) to any component of CAPVAXIVE or to diphtheria toxoid; see additional Select Safety Information below.

The indication for the prevention of pneumonia caused by S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B is approved under accelerated approval based on immune responses as measured by opsonophagocytic activity (OPA). Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.

Selected Safety Information for CAPVAXIVE in the U.S.

Do not administer CAPVAXIVE to individuals with a history of a severe allergic reaction (eg, anaphylaxis) to any component of CAPVAXIVE or to diphtheria toxoid.

Individuals with altered immunocompetence, including those receiving immunosuppressive therapy, may have a reduced immune response to CAPVAXIVE.

The most commonly reported (>10%) solicited adverse reactions in individuals 18 through 49 years of age who received CAPVAXIVE were: injection-site pain (73.1%), fatigue (36.0%), headache (27.5%), myalgia (16.4%), injection-site erythema (13.8%), and injection-site swelling (13.3%).

The most commonly reported (>10%) solicited adverse reactions in individuals 50 years of age and older who received CAPVAXIVE were: injection-site pain (41.2%), fatigue (19.7%), and headache (11.0%).

Vaccination with CAPVAXIVE may not protect all vaccine recipients.

About pneumococcal disease

Pneumococcal disease is an infection caused by a bacteria called Streptococcus pneumoniae. There are about 100 different types (referred to as serotypes) of pneumococcal bacteria, which can affect adults differently than children. Pneumococcal disease can be invasive or non-invasive. Non-invasive pneumococcal illnesses include pneumonia (when pneumococcal disease is confined to the lungs), whereas invasive pneumococcal illnesses include pneumococcal bacteremia (infection in the bloodstream), bacteremic pneumococcal pneumonia (pneumonia with bacteremia) and pneumococcal meningitis (infection of the coverings of the brain and spinal cord). Pneumococcal pneumonia is a type of bacterial pneumonia, which is the most common clinical presentation of pneumococcal disease in adults.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

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Please see Prescribing Information for CAPVAXIVE (Pneumococcal 21-valent Conjugate Vaccine) at https://www.merck.com/product/usa/pi_circulars/c/capvaxive/capvaxive_pi.pdf and Patient Information/Medication Guide for CAPVAXIVE at https://www.merck.com/product/usa/pi_circulars/c/capvaxive/capvaxive_ppi.pdf.

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