Dive Brief:
- Pfizer will push its experimental vaccine candidate for Clostridium difficile into Phase 3 testing in the first half of this year after reporting positive interim results from a Phase 2 trial on Jan. 26.
- The vaccine helped to induce significant increase in antibodies sufficient to neutralize the two main disease-causing toxins produced by C. diff, a sometimes life-threatening gut infection.
- Pfizer's candidate, which has secured a fast track designation from the Food and Drug Administration, is one of several experimental vaccines under investigation by several pharma and biotech companies.
Dive Insight:
The Centers for Disease Control and Prevention has designated C. diff at an “urgent threat” level, reflective of the growing health risk from antibiotic-resistant bacteria.
Complications from the gut infection result in nearly 29,000 deaths and 350,000 hospitalizations annually in the U.S. alone, and nearly eight of 10 people affected are over age 50. Pfizer’s Phase 2 study of its investigational vaccine involved more than 850 healthy adults ages 65 to 85.
“We are very encouraged by these interim immunogenicity and safety results demonstrating robust increases in vaccine-elicited neutralizing antibodies to both toxins, that we believe could provide protection against C. difficile disease,” said Kathrin Jansen, head of Pfizer’s vaccine R&D.
Pfizer is not alone in the prevention effort. The C. Diff Foundation counts a handful of clinical trials underway aimed at preventing or treating the gut infection in various populations.
Sanofi Pasteur, for example, is also developing a vaccine which directs the body’s immune system to produce antibodies against C. diff toxins. It is involved in an ongoing large-scale trial in the U.S. and more than a dozen other countries of its investigational vaccine, Cdiffense.
Also on Jan. 26, British researchers said a large-scale trial found adding Merck’s drug Zinplava (bezlotoxumab) to standard antibiotic treatment can reduce the risk of recurrent infections by nearly 40%. The study involved 2,655 adults at 300-plus hospitals in 30 countries.