In the phase 2 RePreve trial, Lumen Bioscience’s investigational oral biologic LMN-201 plus standard antibiotics achieved global cure in 83.3% of patients with C difficile infection vs 36.4% with placebo, and cut recurrence sixfold (9.1% vs 55.6%) with no drug-related serious adverse events.
The investigational oral biologic LMN-201 achieved statistically significant global cure in patients with Clostridioides difficile infection (CDI) in the phase 2 RePreve trial.¹ Global cure occurred in 83.3% of LMN-201 recipients vs 36.4% of placebo recipients, and recurrence fell from 55.6% to 9.1%.¹ The results will be featured as a late-breaking oral presentation at IDWeek 2026.¹
LMN-201 combines three toxin-binding proteins and an antibacterial enzyme, all produced in engineered spirulina and delivered in oral capsules.¹ The agent is designed for use during and after standard-of-care (SOC) antibiotics, targeting both primary treatment failure and recurrence.¹ According to the therapy’s developer, Lumen Bioscience, prior efforts to improve CDI outcomes have had limited impact, partly because of the high cost and inconvenient administration of existing preventive therapies.¹
In RePreve (NCT05330182), 45 participants with CDI received LMN-201 or placebo during and after SOC antibiotic treatment.¹ Part B was double-blinded and randomized 1:1, with stratification by SOC antibiotic and age.¹ The primary end point, global cure, combined successful primary treatment with prevention of recurrence.¹
Global cure was observed in 10 of 12 LMN-201 recipients (83.3%) vs 4 of 11 placebo recipients (36.4%).¹ The 47-percentage-point risk difference (odds ratio [OR], 8.75) met statistical significance under the prespecified analysis plan, although the announcement did not report a P value or CI.¹ Recurrence occurred in 9.1% of patients receiving LMN-201 plus SOC antibiotics vs 55.6% of those receiving SOC antibiotics plus placebo, a sixfold reduction.¹
LMN-201 reduced primary cure failure by more than 50% relative to SOC alone in Part B (OR, 0.425).¹ This secondary end point trended favorably but did not reach statistical significance.¹ The small number of randomized participants limits the precision of these estimates.
LMN-201 was well tolerated, with adverse event rates similar to placebo and consistent with underlying CDI under antibiotic treatment.¹ No drug-related serious adverse events or deaths occurred.¹ The announcement did not report data on adverse events of special interest or emergence of antimicrobial resistance.¹
“These data support LMN-201’s potential as a first-in-class oral biologic for C. difficile infection,” said Carl Mason, MD, vice president, clinical, at Lumen Bioscience, in the announcement.¹
Mason will present additional RePreve data at IDWeek on October 24 at 1:30 pm ET.¹ Manuscripts for RePreve and an earlier trial assessing safety, tolerability, and gastrointestinal pharmacokinetics (NCT04893239) are in preparation.¹
LMN-201 plus SOC antibiotics achieved global cure in 83.3% of patients vs 36.4% with placebo in the phase 2 RePreve trial.
Recurrence fell sixfold with LMN-201, from 55.6% to 9.1%, with no drug-related serious adverse events or deaths.
C difficile causes nearly half a million US infections annually and remains a CDC urgent antimicrobial resistance threat.
The CDC estimates C difficile causes nearly half a million infections in the US each year.² The agency lists C difficile as an urgent threat in its 2019 Antibiotic Resistance Threats Report, which estimated 223,900 cases in hospitalized patients and 12,800 deaths in 2017.³ When C difficile is added to antimicrobial-resistant infections, the combined US toll exceeds 3 million infections and 48,000 deaths, according to the CDC.³
C difficile accounts for 15% to 25% of all antibiotic-associated diarrhea, according to CDC guidance for clinicians.⁴ Key risk factors include exposure to fluoroquinolones, third- or fourth-generation cephalosporins, clindamycin, and carbapenems; age 65 years or older; immunocompromising conditions; and a health care facility stay within the past 3 months.⁴ A prior history of CDI is itself a recognized risk factor, highlighting the clinical weight of recurrence prevention.⁴
The CDC recommends about 10 days of oral vancomycin or fidaxomicin for confirmed CDI, alongside contact precautions and sporicidal environmental disinfection.⁴ Lumen also cites growing concern about vancomycin resistance as a reason to pursue adjunctive approaches.¹ The CDC plans to release updated burden estimates for at least 19 antimicrobial resistance threats in 2026.³
