Lumen Bioscience's LMN-201 Achieves 100% Initial C. difficile Clinical Cure in Preliminary Cohort of RePreve Trial

—  Strong potential to disrupt market for treatment of C. diff infections
—  RePreve Trial main cohort now recruiting

SEATTLE, April 3, 2025 /PRNewswire/ -- In a landmark achievement for its pioneering spirulina-based drug development platform, Lumen announced today top-line results from the sentinel cohort of its RePreve Clinical Trial evaluating LMN-201 for Clostridioides difficile infection (CDI).

LMN-201 is an oral biologic cocktail, delivered in capsules, intended for use with and following antibiotics to improve clinical outcomes for C. difficile infection. It is made with Lumen's proprietary spirulina-based GMP manufacturing system.

Top-line results:

• 100% Initial Clinical Cure: 21 patients completed 7 days of LMN-201 plus standard of care (SoC) antibiotics (metronidazole, vancomycin, or fidaxomicin). All patients (21/21; 95% confidence interval (CI) 85%-100%) achieved initial clinical resolution, significantly outperforming (p<<0.001) the 80% initial clinical cure rate (625/781; 95% CI 77-83%) observed in the active arm of the large MODIFY I and II studies. The RePreve Trial was designed to facilitate comparisons to the MODIFY trial, which targeted the same patient population with the same SoC antibiotics combined with the IV-infused monoclonal antibody, bezlotoxumab. Patient demographics were similar between RePreve and MODIFY I/II.
  
  
• Significantly Enhanced 28-day Sustained Clinical Cure. What matters most to patients and healthcare systems alike is 28-day sustained clinical cure: the composite of initial clinical cure and prevention of CDI recurrence. Sustained cure rates through Week 4 for SoC alone (MODIFY I/II), SoC plus LMN-201 (RePreve sentinel cohort) and SoC plus bezlotoxumab (MODIFY I/II) were 59.5% (460/773; 95% CI 56-63%), 95.2% (20/21; 95% CI 77-100%) and 68.9% (538/781; 95% CI 66-72%), respectively (see enclosed figure). The improvement in sustained cure through Week 4 between LMN-201 and SoC was 35.7% (p<<0.001) and between LMN-201 and bezlotoxumab was 26.3% (p<0.001).
  
  
• Marked CDI Recurrence Reduction: Only 1 of 21 patients (4.76%; 95% CI 0.24-23%) completing seven days of SoC plus LMN-201 experienced CDI recurrence within 28 days, versus 161 of 621 patients (26%; 95% CI 23-30%) recurrence observed after SoC alone in MODIFY I/II and 87 of 625 (14%; 95% CI 11-17%) after SoC plus bezlotoxumab treatment in MODIFY I/II in the same time period. Of the 21 subjects in the RePreve Trial sentinel cohort who completed seven days of LMN-201, 16 received vancomycin, 4 fidaxomicin, and 1 metronidazole. By comparison, in the Phase 3 trial for Vowst®, patients with three or more prior CDI recurrences who received placebo after vancomycin and fidaxomicin were associated with eight-week CDI recurrence rates of 38% and 46%, respectively (Figure 2 here), illustrating the profound opportunity for improvement in current recurrence rates.
  
  
• LMN-201 Appears to be Safe and Well-Tolerated: No dose-related severe or serious adverse events were reported.

Notably, these sentinel cohort results were achieved with only 7 days of dosing. In the RePreve Trial's main cohort (Part B), the LMN-201 dosing window will increase from 7 days to ~70 days (until 8 weeks after initial clinical cure). This will offer protection throughout the period of greatest risk of CDI recurrence: the weeks immediately after antibiotics treatment when the healthy commensal microbiome naturally re-engrafts.

Observations from the Researchers

"The sentinel cohort data provide strong initial validation for our multi-component approach to CDI," said Dr. George McDonald, Consultant to Lumen and Emeritus Professor of Medicine at the University of Washington. "Seeing zero failures after initial combination treatments and a low recurrence rate in this high-risk group is extremely encouraging. It suggests that LMN-201's tandem mechanism – targeting both the C. diff bacterium and its toxin – can improve outcomes, as it did in preclinical studies." He noted that achieving 100% initial clinical cure, even in a small cohort, is a rarity in published CDI treatment trials. "While our sample size is limited, such an outcome gives us confidence as we move forward," he said. "It's a promising sign, suggesting that LMN-201 could significantly improve patient outcomes and reduce recurrence—the holy grail in C. diff management."

"We are pleased that LMN-201 appears to be safe and well-tolerated in patients," added Lumen's CEO and cofounder, Brian Finrow. "This was our first opportunity to observe LMN-201's effects in a clinical setting, in patients with active C. diff, and the absence of dose-related adverse events is reassuring. We can now proceed to the placebo-controlled phase with a solid foundation of safety and an encouraging preliminary efficacy signal. We look forward to confirming these results in the larger trial, which is recruiting now."

Dr. Jim Roberts, Lumen's cofounder and CSO, concluded: "The formidable amount of novelty built into the Lumen platform comes with substantial challenges, but also the potential for great leaps forward in biologic drug development. We are seeing here the realization of that potential."

If borne out in future studies, the RePreve Trial will mark a major advance in the CDI field. Bezlotoxumab did not improve initial clinical cure rates and only modestly improved CDI recurrence, but came with a risk of heart failure on its label; it was recently withdrawn from the market. Some FMT-based products have reported encouraging results in CDI recurrence prevention, but, due to fundamental incompatibility with antibiotics, cannot be used to improve initial clinical cure rates.

Clinical researchers interested in exploring other uses of LMN-201 in investigator-initiated trials are encouraged to email trials@lumen.bio.

RePreve Trial Design
The RePreve Trial has a two-part design. Enrollment criteria are the same in both cohorts, and, to facilitate comparison, they are nearly identical to those used in the MODIFY trial for bezlotoxumab.

Part A (Sentinel Cohort) was designed to confirm LMN-201's safety in high-risk individuals with CDI, and to allow Lumen to optimize the trial infrastructure and patient recruiting. Twenty-one CDI patients on standard antibiotic therapy were enrolled. All participants in this open-label cohort received LMN-201 in addition to antibiotics, starting within 7 days of diagnosis.

With the sentinel cohort successfully completed, Lumen has begun Part B (main cohort). This pivotal portion is a randomized, double-blind, placebo-controlled study that will enroll approximately 350 patients at research centers across the U.S. Participants are randomized 1:1 to receive either LMN-201 or placebo—in each case alongside standard antibiotic therapy—to rigorously evaluate the drug's efficacy in a larger population. The primary endpoint is "sustained clinical cure" (initial clinical cure plus no recurrence at 12 weeks) relative to placebo. Researchers and participants interested in participating are encouraged to email trials@lumen.bio or visit the official RePreve study webpage.

Background on C. difficile infection
CDI remains a serious and costly problem. Nearly half a million cases occur in the U.S. each year, leading to an estimated ~29,000 deaths and ~$5 billion in hospital costs. Recurrent CDI drives much of this burden: patients who relapse often require extended hospital care and may suffer multiple recurrences. Antibiotic resistance remains a big concern too. CDI is listed as an antimicrobial resistance "Urgent Threat" by the U.S. Centers for Disease Control and Prevention, and researchers are concerned about growing resistance to vancomycin, the main antibiotic used in CDI treatment. Until now, efforts to improve CDI outcomes have had limited impact, due in part to high costs and inconvenient administration of other preventive therapeutics.

About LMN-201 and Lumen Bio
LMN-201 is orally delivered (capsules; no enema or "bowel cleanse" required) and highly scalable, allowing for much broader potential use in routine CDI management. Lumen previously released a preprint with LMN-201's pre-clinical data. A manuscript for peer-reviewed publication is in preparation, to include results of this sentinel cohort (NCT05330182) and an earlier trial assessing LMN-201's safety, tolerability, and gastrointestinal pharmacokinetics (NCT04893239).

Seattle-based Lumen Bioscience has developed a new spirulina-based drug discovery, manufacturing and delivery platform for highly prevalent diseases that have been difficult to address with conventional biopharmaceutical tools. The company's unique platform offers the potential to transform the biologics industry through increased speed, straightforward assembly of cocktail therapeutics, mass-market scale, and exponentially lower costs than legacy approaches.

About the Funding Agency, CDMRP
The work was supported by the Assistant Secretary of Defense for Health Affairs endorsed by the Department of Defense, in the amount of $16,288,194 through the Peer Reviewed Medical Research Program under Award No. HT9425-23-1-0959. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Assistant Secretary of Defense for Health Affairs or the Department of Defense.

Media Contact:
Julie Rathbun
+1.206.769.9219
jrathbun@lumen.bio

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SOURCE Lumen Bioscience