Fzata is Developing a New Hope in the Fight Against C. diff

April 9, 2026

C. diff (short for Clostridioides difficile) is a serious infection that affects the gut. It can cause intense diarrhea, painful cramping, and extreme fatigue—sometimes lasting for weeks. For many patients, it’s not just uncomfortable; it can completely disrupt daily life. Some people recover after treatment and return to normal. But for many others, the infection comes back.

In fact, about 1 in 3 patients will experience a recurrence after their first infection. And once it comes back, it becomes even more likely to return again. For older adults—especially those over 65—the risks are even higher, with severe complications and a significant risk of death.

Until recently, there was only one approved treatment designed specifically to help prevent these repeat infections: Zinplava®, developed by Merck & Co. This IV infusion therapy worked by targeting toxin B produced by C. diff. However, Zinplava was discontinued in early 2025, leaving patients and doctors with a severe gap in targeted options to prevent recurrence.

At the World Vaccine Congress last week, AstraZeneca shared early results on AZD5148 a new similar treatment in clinical development. Like Zinplava, it is infused and targets toxin B but has been designed to stay in the body longer. While promising, it still builds on the same basic idea as Zinplava.

Fzata is forging a completely different path.

Instead of targeting just one toxin, our new drug candidate, FZ002, is designed to neutralize both of the main C. diff toxins (toxin A and toxin B) that cause illness. In fact, FZ002 is tetraspecific with the aim of providing significantly broader protection.

FZ002 is taken by mouth, which means it goes directly to the gut—right where the infection is happening. There, it works by soaking up (neutralizing) toxins before they can cause damage.

Another important difference is that FZ002 is a beneficial yeast called Saccharomyces boulardii, which is known to support gut health. FZ002 is expected to both fight the infection toxins and restore healthy balance to the gut at the same time. This combination—targeting toxins while supporting the gut microbiome—represents a new way to treat C. diff. In preclinical studies, including the highly susceptible ‘Syrian hamster’ model, we have seen FZ002 provide strong protective effects.

FZ002 clinical trials, sponsored by NIH, are planned to begin in summer of 2026 upon FDA clearance. If successful, this could represent a new way to break the cycle of C. diff recurrence. We will share updates as the drug candidate development moves forward.