Pfizer Inc. has presented the results from a phase III study demonstrating the immunogenicity, tolerability and safety of Prevnar 13 (Pneumococcal 13-valent Conjugate Vaccine [Diphtheria CRM197 Protein])in adults infected with human immunodeficiency virus (HIV). The results were presented at the 20th Conference on Retroviruses and Opportunistic Infections (CROI) in Atlanta, Georgia.

These data support planned regulatory submissions seeking to include data on HIV-infected immunocompromised adults in the Prevnar 13 label in the United States, the European Union, and other countries around the world.

In this study, HIV-infected individuals aged 18 years and older who had been previously vaccinated with at least one dose of the conventional pneumococcal polysaccharide vaccine (PPSV) received three doses of Prevnar 13 given six months apart. An immune response to the serotypes in the vaccine was observed after the first dose of Prevnar 13, and each of the two subsequent doses. The clinical relevance of the level of response is not known. The most common local reaction at the injection site was pain and the most common adverse event after vaccination was headache. Adverse events were generally consistent with those expected in this study population.

“Modern advances in medicine have significantly improved HIV case management, but the threat of infectious diseases to those with weakened immune systems is still prevalent,” said Dr Raul Isturiz, Pfizer Medicine Development Group and Scientific Affairs, Vaccines. “In fact, people living with HIV are more susceptible to the potentially devastating effects of pneumococcal diseases.”

For adults with HIV, the incidence of invasive pneumococcal disease is significantly higher and the potential of recurrent disease, most of which represents re-infection, is more likely to occur in these individuals.

“These data add to the compelling body of research for Prevnar 13,” said Dr William Gruber, senior vice president, Pfizer Vaccine Clinical Research and Development. “Pfizer is committed to providing information about this important vaccine across all age groups, especially those with conditions that put them at higher risk of pneumococcal infections, such as those with HIV infection.”

Vaccine safety, tolerability and immunogenicity were evaluated in the phase III, open-label, single-arm trial of 331 adults with HIV aged 18 years or older. All participants had CD4 cell counts of 200 cells/mm3 or higher and had previously received one or more doses of PPSV. Subjects were stratified equally into two groups, those previously vaccinated with one dose of PPSV and those previously vaccinated with two or more doses of PPSV. Participants received three doses of Prevnar 13 at six months intervals. Local and systemic reactions and adverse events were collected.

Pneumococcal disease (PD) is a group of illnesses caused by the bacterium Streptococcus pneumoniae (S. pneumoniae), also known as pneumococcus. It can affect people of all ages, although older adults, young children and individuals with certain chronic medical conditions are at heightened risk. PD is associated with significant morbidity and mortality. Invasive manifestations of the disease include bacteremia (bacteria in the blood) and meningitis (infection of the tissues surrounding the brain and spinal cord).

Prevnar 13 is a vaccine approved for the prevention of invasive disease caused by 13 S. pneumoniae strains (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) in children six weeks through 17 years of age, and in children six weeks through five years for the prevention of otitis media caused by 7 of the 13 strains (4, 6B, 9V, 14, 18C, 19F, and 23F). Based upon immune responses to the vaccine, Prevnar 13 is also approved for adults 50 years of age and older for the prevention of pneumococcal pneumonia and invasive disease caused by the 13 vaccine strains.

Prevnar 13 is not 100 per cent effective and will only help protect against the 13 strains included in the vaccine. Effectiveness when given less than five years after a pneumococcal polysaccharide vaccine is not known.

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