Pfizer says it could be on course to file for approval of its new generation pneumococcal conjugate vaccine in the US before the end of the year, as it tries to protect its franchise from Merck & Co’s rival shot.
Top-line results from a phase 3 trial of 20-valent candidate PF-06482077 – a follow-up to Pfizer’s 13-valent Prevnar 13 product – showed that the vaccine was safe and immunogenic in adults not previously vaccinated against pneumococcal disease.
The 3,880-patient trial found that an immune response with PF-06482077 – also known as 20vPnC – was successfully stimulated against all 13 pneumococcal serotypes in Prevnar 13 plus six of the seven additional strains covered by Merck’s polysaccharide-based Pneumovax 23 product.
It narrowly failed to meet the non-inferiority threshold against one strain covered by Pneumovax 23, according to Pfizer.
Pneumococcal disease is caused by Streptococcus pneumoniae, and includes non-invasive illnesses like pneumonia, sinusitis and middle ear infections, as well as invasive diseases like meningitis.
The most vulnerable populations are children under the age of two, adults 65 years and older and people with suppressed immune systems or chronic diseases.
In the US, Prevnar 13 is recommended for all children younger than two, plus older children with conditions that elevate their risk of pneumococcal infections, while Pneumovax 23 is generally used in at-risk adults and smokers as well as people aged 65 or over.
Merck is hoping to muscle into Prevnar 13’s position in paediatric immunisation with V114, a 15-valent conjugate vaccine which is in phase 3 trials and has picked up a breakthrough designation from the FDA for use in children.
Last year, Merck reported phase 2 data showing that V114 was non-inferior to Prevnar 13 in healthy infants aged 6 to 12 weeks, setting the programme back on course after earlier studies showed it failed to meet the non-inferiority threshold on three strains covered by Pfizer’s shot.
PF-06482077 is Pfizer’s bid to stay ahead of its rival and defend its Prevnar franchise, which brought in $5.85bn in sales last year, and also extend the use of the franchise in adults, an area where Prevnar 13 has been failing back.
“The results from this pivotal study provide evidence that the 20vPnC vaccine is expected to have a comparable safety profile and likely be as effective as Prevnar 13 in helping prevent invasive pneumococcal disease…and also effective against disease due to the seven additional pneumococcal serotypes in adults 18 years of age or older,” said Pfizer’s senior vice president and head of vaccine R&D Kathrin Jansen.