Synthetic Biologics, Inc., a late-stage clinical company developing therapeutics that preserve the microbiome to protect and restore the health of patients, announced that the US Food and Drug Administration (FDA) has granted a Breakthrough Therapy Designation for SYN-004 (ribaxamase) for the prevention of Clostridium difficile infection.

SYN-004 (ribaxamase) is the company's first-in-class oral enzyme designed to protect the gut microbiome from disruption caused by certain intravenous (IV) beta-lactam antibiotics.

The Breakthrough Therapy Designation is based on data from the successful phase 2b clinical trial of ribaxamase, which met its primary endpoint of significantly reducing CDI. FDA Breakthrough Therapy Designation is intended to expedite development and review timelines when preliminary clinical evidence indicates that a drug may demonstrate substantial improvement on one or more clinically significant endpoints over available therapies for serious or life threatening diseases. If approved by the FDA, SYN-004 (ribaxamase) would be the first available drug designed to prevent Clostridium difficile infection by protecting the gut microbiome from antibiotic-mediated dysbiosis.

"We are delighted by the FDA's recognition of ribaxamase's potential to prevent CDI, and the dire need to fill the current void of an approved intervention," said Jeffrey Riley, president and chief executive officer. "Following this announcement, we have been asked and anticipate requesting a Type-B multidisciplinary meeting with the Agency for a comprehensive discussion on the overarching, high-level drug development plan and pathway to licensure for ribaxamase. We look forward to working closely with the FDA throughout the development and review process and remain dedicated to bringing this potentially paradigm-shifting approach to antibiotic therapy to patients in critical need."

Clostridium difficile infection is the number one hospital acquired infection in the US, with more than 453,0001 patients diagnosed annually. CDI results in approximately 29,0001 deaths, $1.5 billion1 in additional healthcare costs, as well as significant and sometimes prolonged illness.

SYN-004 (ribaxamase) is a first-in-class oral enzyme designed to degrade certain IV beta-lactam antibiotics within the GI tract and maintain the natural balance of the gut microbiome for the prevention of CDI, pathogenic overgrowth and the emergence of antimicrobial resistance (AMR). Synthetic Biologics initiated a phase 2b proof-of-concept clinical trial intended to evaluate the effectiveness of ribaxamase to prevent the onset of primary C. difficile infection (CDI), antibiotic-associated diarrhea (AAD) and the emergence of antimicrobial resistance (AMR) in patients hospitalized with a lower respiratory infection and receiving IV ceftriaxone. Results from this trial indicate that patients receiving ribaxamase achieved a 71.4% relative risk reduction (p-value=0.045) in CDI rates compared to patients receiving placebo. Analysis of the data also demonstrated a significant reduction in new colonization by vancomycin-resistant enterococci (VRE) for patients receiving ribaxamase compared to placebo (p-value=0.0002). Adverse events reported during this trial were comparable between treatment and placebo arms. Analysis of data from several exploratory endpoints designed to evaluate ribaxamase's ability to prevent the emergence and proliferation of AMR in the gut microbiome is ongoing.