European regulators have started their review of Pfizer's application to market pneumococcal vaccine Prevenar 13 more widely in adults, which could swell peak sales by $1bn or more.
Prevenar 13 has already become firmly established as a key component of childhood vaccination campaigns - with sales running at around $4bn a year - but could get a big boost from approval to prevent community-acquired pneumonia (CAP) in the elderly.
The vaccine is already approved in Europe for preventing invasive pneumococcal disease in adults, a less common but more serious infection characterised by the presence of Streptococcus pneumoniae bacteria in the blood and other normally sterile sites in the body.
Analysts at JP Morgan have suggested that approval of the new, broader label could lead to Prevenar 13 (which is sold as Prevnar 13 in the US and some other markets) becoming widely recommended in adults and add another $1.5bn to its peak sales potential.
Pfizer has submitted a marketing application in the US to add the new indication to Prevnar 13's labelling, and is due to hear the verdict of the FDA in September. In the meantime, the US Advisory Committee on Immunization Practices (ACIP) is scheduled to deliver a verdict on expanding the label of the vaccine next week.
Both US filing, and its acceptance for review by the European Medicines Agency (EMA), are based on the results of the 85,000-patient CAPiTA trial, which showed that the vaccine halved CAP rates, with significant reductions in both non-invasive and invasive disease, in adults aged 65 and older.
Pfizer senior vice-president of vaccine R&D, Emilio Emini, said pneumococcal pneumonia continues to be a serious health problem, causing significant illness and mortality in older adults.
"The results of the CAPiTA study underscore the potential benefits of Prevenar 13 in preventing disease in this age group," he said.
Albert Bourla, who heads Pfizer's vaccines business, said the expanded label for Prevenar 13 is "a great opportunity … because there is significant unmet need among the 300m adults who are greater than 65 years of age in the world".
"We expect the Prevnar 13 to be the leading adult vaccination given the strength of our data," he continued, adding: "There could also be an additional catch-up opportunity for adults greater than 65 who have already received the old generation vaccine."
Pfizer said it plans to submit applications in other major markets, including Australia, Canada and Japan, later this year.