RBX2660 drug candidate highly effective against recurrent Clostridium difficile infection

Rebiotix Inc. announced today that results of the Phase 2 PUNCH™ CD Study found that the overall efficacy of RBX2660 in the treatment of recurrent Clostridium difficile infection was 87.1%. The study also found that administration of RBX2660 was well-tolerated and demonstrated satisfactory safety in the 60-day interim analysis.

The results of a 60-day interim analysis of the PUNCH CD study, the first prospective multi-center study of a next generation, standardized, commercially prepared microbiota restoration therapy for recurrent CDI were presented at IDWeek 2014.

Clostridium difficile infection, characterized by severe diarrhea, is a leading healthcare acquired infection and is linked to 14,000 deaths in the U.S. annually. The U.S. Centers for Disease Control recently termed CDI an urgent public health threat. Recurrent CDI is especially challenging to treat, and there are no indicated drugs for the condition.

The primary objective of the PUNCH CD study was product-related adverse events (AEs). A secondary objective was CDI resolution. A total of 40 patients at 11 centers in the U.S. were enrolled in the study. All of the patients had multi-recurrent CDI and had failed standard therapy. The PUNCH CD patient population was primarily elderly and female with multiple co-morbidities, thus reflecting the real-world population of patients with recurrent CDI who present with unmet medical needs.

A total of 34 patients received at least one dose of RBX 2660 administered via enema. A second dose was permitted if CDI recurred < 8 weeks after the first dose. Overall efficacy of RBX2660, defined as the absence of CDI symptoms at 8 weeks after the last dose, was 87.1%. Adverse events were predominantly mild to moderate flatulence, belching, and constipation which were self-limiting. There were no serious adverse events linked to RBX2660 or its administration.

"Years of experience indicate microbiota therapy is highly efficacious for treatment of recurrent CDI. However, adequate data have been lacking on safety," said Erik R. Dubberke, MD, MSPH, a PUNCH CD investigator and Director, Section of Transplant Infectious Diseases at Washington University School of Medicine, St. Louis, MO. "The phase 2 study indicates RBX2660 efficacy is consistent with past studies, and it is safe and easy to administer."

The study represents a significant step forward in Rebiotix's efforts to develop a durable cure for recurrent CDI that is debilitating to patients. RBX2660 will undergo further study in a Phase 2B randomized controlled trial scheduled to begin later this fall.