Pfizer's Pediatric Vaccine Prevnar 13 Approved

When Pfizer (PFE) announced its most recent quarterly results, analysts grilled management about the status of the Prevnar 13 pediatric vaccine application. Well, they can all relax now: Pfizer on Wednesday announced that the U.S. Food and Drug Administration has finally approved the vaccine.

Prevnar 13 was approved for the vaccination of children aged 6 weeks through 5 years to protect against 13 varieties of the Streptococcus pneumoniae bacteria, which can cause such serious illnesses as sepsis, infections of the blood, meningitis and pneumonia.

The vaccine will essentially replace the original blockbuster Prevnar vaccine, which only protected against seven types of the bacteria. The new drug was actually developed by Wyeth -- once again proving the merits of that acquisition. Prevnar generated $2.7 billion in sales in 2008. Analysts have estimated sales of Prevnar 13 will be between $5 and $6 billion in 2014-2015. No wonder Pfizer shares are up 1.3%.

Of key importance is the fact that the new vaccine offers protection against a common subtype of the bacteria that became resistant to antibiotics about five years ago. Prevnar 13 is the only vaccine to protect against this strain.

Sales Could Partially Offset Lipitor Declines

Pfizer expects the vaccine, which has already been approved in 38 countries and is expected to be introduced in the U.S. in the first quarter, might become its biggest seller after Lipitor. Generic competition for Lipitor, worth some $12 billion a year in sales, could start as soon as next year. Given those numbers, gains for the vaccine could not fully offset the expected decline in Lipitor's sales; in addition, Prevnar 13 faces competition from rival vaccines: GlaxoSmithKline's (GSK) Synflorix and Merck's (MRK) Pneumovax 23, the first of which has been approved in Europe, and the second of which is approved for adults.

Meanwhile, Prevnar 13 is also being studied in adults in global Phase III clinical trials, with regulatory submissions expected later this year. An approval for adult use "would open up essentially hundreds of millions of additional patients" Geno Germano, president of Pfizer's specialty care unit told The New York Times. Pfizer has estimated it could add $1.5 billion in sales.

Infections caused by the seven types of bacteria Prevnar protects against had dropped 99% by 2007, according to the FDA. Prevnar 13 offers 90% protection, compared to Prevnar's 80%, and Pfizer has estimated this could reduce deaths from pneumococcus by an additional 9,800 over 10 years. It's no wonder that already, the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices has recommended the use of Prevnar 13 for healthy children as indicated by the FDA's approval.

More Effective Against Invasive Diseases Than Ear Infections

The FDA is requiring Pfizer to conduct several post-marketing analyses on the vaccine's safety and efficacy. In the Phase III studies, which involved more than 7,000 infants and young children, the vaccine had common side effects. However, somewhat disturbing was the temporary pause of breathing following vaccination that has been observed in some infants born prematurely.

Pfizer noted that Prevnar 13 may not protect all individuals receiving the vaccine, and that its protection against ear infections is expected to be less than that for invasive disease. As a recent mumps outbreak in New York among children who had received the MMR vaccination has shown, vaccines are not perfect. Mumps is known to be the weakest link in that vaccine.

According to a World Health Organization 2002 estimate, pneumococcal disease is the leading cause of vaccine-preventable death worldwide in children younger than 5 years old. Pfizer plans to introduce the vaccine in developing countries as well.