The financing supports phase 3 evaluation of Sidiprev, a first-in-class, nonantibiotic therapy designed to prevent C difficile infections, a leading US health care–associated threat.
LPOXY Therapeutics, Inc, has announced a $28 million Series A financing agreement with 5 Horizons Ventures to fund the pivotal STOP-Cdiff study. The trial will evaluate Sidiprev, a first-in-class, nonantibiotic therapy designed to prevent Clostridioides difficile infections (CDI), which the Centers for Disease Control and Prevention classifies as an urgent public health threat causing approximately 80 deaths daily in the United States.
The STOP-Cdiff trial will be a randomized, placebo-controlled superiority study enrolling approximately 500 hospitalized patients at elevated risk for CDI due to age and antibiotic exposure. Conducted under the US Food and Drug Administration (FDA)'s Limited Population Pathway for Antibacterial and Antifungal Drugs (LPAD), the trial is intended to serve as the registrational study for Sisiprev. LPOXY anticipates trial initiation in the third quarter of 2026, with a regulatory filing projected for 2029.
Sidiprev is formulated as an orally administered, enteric-coated capsule that delivers a controlled release of oxygen into the lower gastrointestinal tract. The oxygen-rich environment is designed to inhibit anaerobic pathogens such as C difficile. Additional mechanisms may include suppression of toxin production and mucosal anti-inflammatory effects.
C difficile remains a leading cause of health care–associated infections, particularly among hospitalized patients receiving antibiotics. No therapies are currently approved to prevent primary CDI. Preventive approaches that avoid antibiotic use are considered critical to address antimicrobial resistance and health care costs associated with CDI-related complications.
LPOXY closed $28M Series A funding with 5 Horizons Ventures to advance the STOP-Cdiff pivotal trial of SIDIPREV, targeting prevention of C difficile infections.
SIDIPREV is an oral capsule that delivers oxygen to the gut to inhibit anaerobic pathogens, suppress toxin production, and reduce inflammation.
The trial will enroll 500 high-risk hospitalized patients, with initiation expected in Q3 2026 and a regulatory filing projected for 2029
Earlier Developments
In January 2025, LPOXY announced the acquisition of key assets from Xeno Biosciences to support Sidiprev development. The acquisition included regulatory filings; FDA correspondence; chemistry, manufacturing, and control data; intellectual property; and results from phase 1 and 1b studies demonstrating safety of the active pharmaceutical ingredient.
At that time, Larry D. Sutton, MD, PhD, CEO of LPOXY, explained in an interview that Sidiprev delivers oxygen into the gastrointestinal tract, a mechanism toxic to anaerobic C difficile. Proposed additional effects include suppression of toxin production, enhancement of immune clearance, and modulation of the gut microbiome to reduce spore germination. Sutton noted that, unlike vaccine-based approaches that did not meet efficacy end points in late-stage trials, Sidiprev is designed for coadministration with antibiotics, the primary risk factor for CDI, to prevent infections before onset.
LPOXY has indicated plans to use LPAD to target high-risk populations, such as older adults hospitalized with community-acquired pneumonia who are treated with broad-spectrum antibiotics. The company has also reported ongoing efforts to establish partnerships to expand hospital access and distribution once the therapy progresses through pivotal trials.
