10 September 2019 - - US-based pharmaceutical company Pfizer Inc. (NYSE: PFE) has received positive preliminary results following administration of three doses in a four-dose series for a Proof-of-Concept Phase 2 study (B7471003) to assess safety and immunogenicity of its 20-valent pneumococcal conjugate vaccine (20vPnC) candidate, PF-06482077, being investigated for the prevention of invasive disease and otitis media caused by Streptococcus pneumoniae serotypes contained in the vaccine in healthy infants, the company said.

Pfizer's 20vPnC candidate includes the 13 serotypes contained in Prevnar 13 (Pneumococcal 13-valent Conjugate Vaccine [Diphtheria CRM197 Protein]) plus seven additional serotypes (8, 10A, 11A, 12F, 15B, 22F, and 33F).

B7471003 is a randomized, double-blind Phase 2 proof-of concept study to assess the safety and immunogenicity of 20vPnC in approximately 460 healthy infants.

Subjects were randomised equally to receive a 4-dose series of either 20vPnC or Prevnar 13 at and 12 months of age.

Local reactions and systemic events were collected for 7 days after each vaccination. Adverse events were collected in a similar fashion to the Prevnar 13 infant programme.

Pfizer will seek to present and publish outcomes from this clinical trial at a future date once safety and immunogenicity data has been analyzed following the completion of the four-dose regimen.

Pfizer has completed enrollment in its three Phase 3 pivotal clinical trials (NCT03828617, NCT03835975 and NCT03760146) evaluating 20vPnC for the prevention of invasive disease and pneumonia in adults 18 years and older.

Combined, these three trials have enrolled more than 6,000 adult subjects, including populations of vaccine-naïve adults and adults with prior pneumococcal vaccination.

Pfizer remains on track to submit the Biologics License Application for the adult 20vPnC indications to the US FDA by the end of 2020, subject to the successful completion of these Phase 3 studies.

The seven new serotypes included in 20vPnC are global causes of invasive pneumococcal disease, and are associated with high case-fatality rates, antibiotic resistance and/or meningitis.

Together, the 20 serotypes included in 20vPnC are responsible for the majority of currently circulating pneumococcal disease in the US and globally.

On September 20, 2018, Pfizer announced the US Food and Drug Administration granted Breakthrough Therapy Designation for 20vPnC for the prevention of invasive disease and pneumonia in adults age 18 years and older.

Breakthrough Therapy Designation is designed to expedite the development and review of drugs and vaccines that are intended to treat or prevent serious conditions and preliminary clinical evidence indicates that the drug or vaccine may demonstrate substantial improvement over available therapy on a clinically significant endpoint(s).

Drugs and vaccines that receive Breakthrough Therapy Designation are eligible for all features of the FDA's Fast Track designation, which may include more frequent communication with the FDA about the drug's development plan and eligibility for Accelerated Approval and Priority Review, if relevant criteria are met.

The FDA previously granted Fast Track designation for 20vPnC in September 2017 for use in adults aged 18 years and older.

The FDA's Fast Track approach is a process designed to facilitate the development and expedite the review of new drugs and vaccines intended to treat or prevent serious conditions and address an unmet medical need.

Additionally, in May 2017 the FDA granted Fast Track status for a pediatric indication for 20vPnC.