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

Rhea-AI Summary

Merck (NYSE: MRK) has received European Commission (EC) approval for CAPVAXIVE®, a 21-valent pneumococcal conjugate vaccine for adults aged 18 and older. The vaccine is designed to prevent invasive pneumococcal disease and pneumonia caused by 21 specific Streptococcus pneumoniae serotypes.

The approval, based on the Phase 3 STRIDE clinical program, covers all 27 EU member states, Iceland, Liechtenstein, and Norway. This marks CAPVAXIVE's fourth regulatory approval, following authorizations in the U.S. (June 2024), Canada (July 2024), and Australia (January 2025).

Clinical data demonstrated that CAPVAXIVE was non-inferior to existing vaccines (PCV20 and PPSV23) for shared serotypes and showed superiority for unique serotypes. The vaccine exhibited comparable safety profiles to other pneumococcal vaccines across multiple clinical trials, including studies with immunocompromised patients and those receiving concurrent influenza vaccination.

Positive

• Fourth major market approval expands global commercial potential
• Demonstrated superiority for unique serotypes compared to existing vaccines
• Lower adverse event rate (71.6%) compared to PCV15+PPSV23 (91%) in HIV patients
• Successful concomitant administration with flu vaccine shows flexibility in vaccination schedules

Negative

• Market availability dependent on country-specific reimbursement procedures, potentially delaying commercialization
• Did not meet superiority criteria for serotype 15C

Insights

Pharmaceutical Regulatory Analyst

The European Commission's approval of Merck's CAPVAXIVE marks a significant regulatory milestone, extending authorization across all 27 EU member states plus Iceland, Liechtenstein, and Norway. This pneumococcal 21-valent conjugate vaccine represents Merck's fourth major market approval following earlier authorizations in the US, Canada, and Australia.

What distinguishes this approval is the compelling clinical differentiation demonstrated in the Phase 3 STRIDE program. CAPVAXIVE showed non-inferiority to PCV20 for 10 shared serotypes while demonstrating superiority for 10 of 11 serotypes unique to CAPVAXIVE. The European epidemiological data presented directly supports this clinical advantage, with country-level analysis confirming CAPVAXIVE covers serotypes responsible for more invasive pneumococcal disease cases in adults compared to competing vaccines.

The immunogenicity data across multiple populations - including adults over 50, younger adults 18-49, previously vaccinated individuals, and immunocompromised patients - establishes a robust clinical foundation. This comprehensive data package likely facilitated the regulatory pathway and should support downstream market access negotiations.

While the approval is secured, the article specifically notes that actual market availability will depend on country-specific reimbursement procedures, highlighting the typical two-step process for vaccine commercialization in Europe.

Infectious Disease Specialist

This approval introduces a meaningfully differentiated pneumococcal vaccine to the European market. CAPVAXIVE's 21-valent formulation addresses a critical clinical challenge in adult pneumococcal prevention - namely, the evolution of disease-causing serotypes beyond those covered by earlier generation vaccines.

The serotype coverage is particularly noteworthy. The country-level epidemiological data presented demonstrates CAPVAXIVE targets serotypes responsible for a higher percentage of invasive pneumococcal disease cases compared to the 20-valent alternative. This expanded coverage represents a potential advance in protection, especially for vulnerable populations.

The STRIDE clinical program data reveals important immunological advantages. Beyond meeting non-inferiority endpoints for shared serotypes, CAPVAXIVE demonstrated superior immune responses for most unique serotypes. The comparable safety profile to established vaccines is equally important for population-level implementation.

The concomitant administration study with influenza vaccine (STRIDE-5) addresses a practical clinical consideration, showing compatibility with routine adult vaccination protocols. Similarly, the data in HIV-positive patients (STRIDE-7) and previously vaccinated individuals (STRIDE-6) provides needed evidence for implementation across diverse populations.

From a public health perspective, this approval offers European clinicians an additional tool against pneumococcal disease, which remains a significant cause of morbidity and mortality in adults, particularly those 65+ and those with chronic conditions.

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

RAHWAY, N.J.--(BUSINESS WIRE)-- 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:

Coverage of Serotypes Responsible for IPD in Select EU Countries
Country	Age	Year Reported	CAPVAXIVE	PCV20
Germany	≥60	2020	~84%	~58%
France	>65	2022	~85%	~63%
Italy	>65	2023	~77%	~64%
Spain	>65	2020	~82%	~62%

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.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

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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Media Contacts:

Olivia Finucane

0044 7881 262476

Olivia.finucane@msd.com

Chrissy Trank

(640) 650-0694

chrissy.trank@merck.com

Investor Contacts:

Peter Dannenbaum

(732) 594-1579

peter.dannenbaum@merck.com

Damini Chokshi

(732) 594-1577

damini.chokshi@merck.com

Source: Merck & Co., Inc.

FAQ

What are the key benefits of Merck's CAPVAXIVE compared to existing pneumococcal vaccines?

CAPVAXIVE (MRK) covers 21 serotypes and showed superiority for unique serotypes not covered by existing vaccines, while maintaining non-inferiority for shared serotypes with PCV20 and PPSV23.

When will CAPVAXIVE be available in European markets after EC approval?

The availability timing in individual EU countries depends on completion of local reimbursement procedures following the EC approval.

What age groups are approved for Merck's CAPVAXIVE in the EU?

CAPVAXIVE is approved for individuals 18 years of age and older for prevention of invasive pneumococcal disease and pneumonia.

How did CAPVAXIVE perform in clinical trials with immunocompromised patients?

In the STRIDE-7 trial, CAPVAXIVE showed immunogenicity for all serotypes and had fewer adverse events (71.6%) compared to PCV15+PPSV23 (91%) in HIV patients.

What regions has Merck's CAPVAXIVE received approval in as of 2025?

CAPVAXIVE has been approved in the U.S. (June 2024), Canada (July 2024), Australia (January 2025), and now the European Union.