US-based pharmaceutical firm Pfizer has reported positive top-line results from its Phase II study of Clostridium difficile (C. difficile) vaccine PF-06425090 to prevent C. difficile infection (CDI).
PF-06425090 is an investigational vaccine candidate designed with a functional antibody response to neutralise toxins A and B, the two disease-causing toxins generated by C. difficile.
Spore-forming pathogen C. difficile releases toxins that might lead to life-threatening infections such as diarrhea, pseudomembranous colitis, asymptomatic colonisation, toxic megacolon and intestinal perforation.
The randomised, placebo-controlled, observer-blinded Phase II study evaluated the safety, tolerability, and immunogenicity of the vaccine in more than 850 healthy adults aged 65 to 85.
Pfizer vaccine research and development senior vice-president and head Kathrin Jansen said: “Despite improved infection control measures, C. difficile disease continues to rise, further augmenting an already urgent public health threat with particular negative impact on older adults.
“We are very encouraged by these interim immunogenicity and safety results demonstrating robust increases in vaccine-elicited neutralising antibodies to both toxins, that we believe could provide protection against C. difficile disease.”
The study assessed two dose levels 100mcg and 200mcg of the vaccine candidate on two different three-dose vaccination schedules.
Based on the current data from the pre-planned interim analysis, the firm intends to initiate the Phase III trial for the vaccine in the first half of this year.
In August 2014, C. difficile vaccine received fast track designation from the US Food and Drug Administration (FDA).