Pfizer Inc. announced that results from a study analyzing real-world effectiveness data found that Prevnar 13 (pneumococcal 13-valent conjugate vaccine [diphtheria CRM197 Protein]) reduced the risk of hospitalization from vaccine-type pneumococcal community-acquired pneumonia (CAP) by 73% (95% CI: 12.8-91.5%) in adults aged 65 and older.

Importantly, Prevnar 13 (PCV13) worked under real-world conditions where people received pneumococcal vaccination as advised by their health care providers, and many had underlying medical conditions that increase the risk for pneumococcal pneumonia. The results were published in Clinical Infectious Diseases.

The study, conducted jointly between the University of Louisville School of Medicine and Pfizer, was designed as a test-negative case-control study and provides evidence supporting the findings of the landmark randomized, controlled Community-Acquired Pneumonia Immunization Trial in Adults (CAPiTA). CAPiTA was one of the largest vaccine efficacy trials ever conducted in older adults and demonstrated a significant reduction by 45.6% (95.2% CI: 21.8-62.5; p<0.001) in vaccine-type pneumococcal CAP in adults vaccinated with PCV13. The Community-Acquired Pneumonia Immunization Trial in Adults (CAPiTA) excluded people with high-risk medical conditions.2 The safety profile of PCV13 in CAPiTA was consistent with studies previously conducted in adults.

“The new effectiveness data further demonstrate that vaccinating adults aged 65 and older against pneumococcal pneumonia with PCV13 could help prevent hospitalization and save lives,” said Dr. Julio A. Ramirez, Chief, Division of Infectious Diseases, University of Louisville School of Medicine, and one of the study authors. “Specifically, based on a 73% vaccine effectiveness observed in this study, we estimate that PCV13 vaccination in adults 65+ might prevent thousands of CAP-related hospitalizations.”

Streptococcus pneumoniae, also known as pneumococcus, is the most common bacterial cause of CAP. Pneumococcal pneumonia can be classified as non-invasive, when bacteria cause infection in the lungs but are not detected in the blood, or invasive, when bacteria also enter the bloodstream (bacteremic pneumonia) or another normally sterile site in the body. For every one case of invasive pneumococcal pneumonia in adults, it is estimated that at least three cases of non-invasive pneumococcal pneumonia occur. While non-invasive forms of pneumococcal disease are typically more common, the invasive types of disease are generally more severe.

“These results complement the Community-Acquired Pneumonia Immunization Trial in Adults study, suggesting that PCV13 is effective under the real-world circumstances of an immunization program, including a percentage of individuals with high-risk conditions that were excluded from the Community-Acquired Pneumonia Immunization Trial in Adults analysis,” said Dr. Luis Jodar, Chief Medical and Scientific Affairs Officer, Vaccines Medical Development, Scientific and Clinical Affairs, Pfizer Inc. “These findings, as well as the continuous circulation of the 13 serotypes included in PCV13 among adults, confirm the importance of direct vaccination in this age group.”

The study was nested within a population-based surveillance study of adults in Louisville, Kentucky, United States, who were hospitalized with CAP. The population-based surveillance study prospectively enrolled adults in Louisville, Kentucky who were hospitalized with CAP in one of nine adult acute-care hospitals between October 7, 2013 and September 30, 2016. The nested case-control sub-study analyzed a subset of CAP patients enrolled between April 1, 2015 and April 30, 2016. The study used an established measure of vaccine effectiveness known as a test-negative design. In this study, patients hospitalized with CAP had routine cultures performed as well as a urine antigen detection test to determine if they had infections with pneumococcal serotypes included in the vaccine, PCV13. Patients with pneumonias caused by pneumococcal serotypes included in PCV13 were considered “cases,” and “control” subjects were patients with CAP who tested negative for PCV13 serotypes.

Considerations for Using Real-World Data: Clinical studies analyzing real-world data have the potential to supplement randomized trials by providing additional information about how a medicine performs in routine medical practice. Clinical studies analyzing real-world data have several limitations. For example, the source and type of data used may limit the generalizability of the results and of the endpoints. Due to these limitations, real-world data analyses are not generally used as stand-alone evidence to validate the efficacy and/or safety of a treatment.

In the study period, there were a total of 2,034 CAP hospitalizations with a median age of 76 years. Researchers identified PCV13 serotypes in 68 (3.3%) of patients who served as the case subjects. Cases were less likely to have received PCV13 vs. controls (4.4% vs. 14.5%, P=0.02). This indicated that PCV13 use in adults aged 65 and older can prevent 73% of CAP caused by PCV13 serotypes.

Prevnar 13 (pneumococcal 13-valent conjugate vaccine [diphtheria CRM197 Protein]) was approved in the US in February 2010 for use in infants and young children.
 
The vaccine is indicated in children 6 weeks through 17 years (prior to the 18th birthday) for active immunization for the prevention of invasive disease caused by Streptococcus pneumoniae (S. pneumoniae) serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F, and for children 6 weeks through 5 years of age (prior to the 6th birthday) for the prevention of otitis media caused by 7 of the 13 serotypes only (4, 6B, 9V, 14, 18C, 19F, and 23F).

In adults 18 years of age and older, Prevnar 13 is indicated for active immunization for the prevention of pneumonia and invasive disease caused by S. pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F.

Prevnar 13 does not protect against disease caused by S. pneumoniae serotypes that are not in the vaccine

Prevnar 13 is the trade name in the United States, Canada, and Taiwan. Outside these countries, it is marketed as Prevenar 13 (pneumococcal polysaccharide conjugate vaccine [13 – valent, adsorbed]). It is approved in the EU and other countries for use in infants, older children and adolescents aged 6 to 17 years. In addition, Prevenar 13 is approved for use in adults 50 years of age and older in more than 100 countries. Prevenar 13 is approved in the EU and more than 40 other countries for use in adults 18 to 49 years of age.