MF-300 Phase 1 results demonstrate robust target engagement with no safety concerns identified.

Epirium Bio Inc. (Epirium), a clinical-stage biopharmaceutical company advancing medicines for neuromuscular and fibrotic diseases, announced today that new clinical and translational data for MF-300 will be presented in two oral sessions at the Intrinsic Capacity, Frailty and Sarcopenia Research Conference (ICFSR) 2026, taking place March 10-12 in Washington, DC.

MF-300 is an investigational, first-in-class, orally administered, 15-hydroxyprostaglandin dehydrogenase (15-PGDH) enzyme inhibitor in development for the treatment of age-related muscle weakness, or sarcopenia. Inhibition of 15-PGDH enhances endogenous PGE2 signaling, a pathway associated with the resolution of inflammation and tissue repair. Preclinical data show that PGE2 plays a crucial role in promoting aged muscle strength by improving muscle quality. The presentations highlight results from Epirium’s completed Phase 1 study together with translational research linking preclinical efficacy to the observed clinical biomarker responses.

“ICFSR is an important forum for highlighting innovative approaches to address age-related muscle weakness,” said Dr. Leigh MacConell, Head of Clinical Development at Epirium Bio. “The data being presented demonstrate that the magnitude of biomarker responses observed clinically is comparable to levels associated with improvements in muscle force in aged preclinical models, further supporting the biological rationale for this program as we prepare to advance MF-300 into Phase 2 clinical development.”

Epirium plans to initiate a randomized, placebo-controlled Phase 2b clinical trial evaluating the effect of MF-300 on functional performance and muscle strength in patients with age-related sarcopenia in the second half of 2026.

ICFSR Oral Presentations

Thursday, March 12 at 12:20 PM | LB 28

Title: Phase 1 clinical evaluation of MF-300 in older adults: an investigational first-in-class oral small molecule in development for sarcopenia.

This late-breaker presentation will report findings from a randomized, placebo-controlled single- and multiple-ascending dose (SAD/MAD) Phase 1 study evaluating MF-300 in 88 participants, including 70 adults aged ≥18 to ≤65 years and 18 older adults aged >65 to ≤75 years.

MF-300 was safe and well tolerated across evaluated dose ranges, with no dose-limiting toxicities observed. Pharmacokinetic analyses showed comparable exposure profiles between younger and older participants, indicating that age did not meaningfully affect MF-300 pharmacokinetics. Pharmacodynamic analyses demonstrated clear evidence of target engagement with dose-related changes in PGE2 and its metabolites consistent with pharmacologic inhibition of 15-PGDH. The pattern of biomarker modulation with MF-300 was comparable between the younger and older adults. At the maximally efficacious dose of MF-300, 75% of younger healthy adult and 100% of older adult participants achieved clinically relevant changes – at least a 60% increase in PGE2 levels and 50% reduction in PGE-MUM, a urinary metabolite reflecting inhibition of PGE2 degradation.

Thursday, March 12 at 3:30 PM | OC 49

Title: Bridging preclinical efficacy with Phase 1 target engagement of MF-300, an investigational first-in-class oral agent for sarcopenia.

This presentation highlights translational research connecting preclinical efficacy with clinical biomarker responses observed in the Phase 1 study. In naturally aged mice, a model of sarcopenia, MF-300 increased muscle force in fast-twitch muscle fibers, the muscle type most affected by aging. MF-300 administration also improved age-related effects on bone micro-architecture associated with increased fracture risk. These data are consistent with reported biological effects of PGE2 and suggest that 15-PGDH inhibition may offer a broader strategy for addressing the musculoskeletal consequences of aging and overall mobility in older adults.

The studies also evaluated PGE-MUM as a translational biomarker of pharmacologic activity. In aged mice, MF-300 administration produced a 43% reduction in PGE-MUM compared to animals receiving vehicle. This reduction correlated with statistically significant improvements in muscle force, restoring approximately 79% of muscle strength to that of a younger comparator group. Importantly, the magnitude of PGE-MUM reduction observed in the Phase 1 clinical study was comparable to reductions associated with efficacy in aged mouse models, supporting the biomarker’s potential relevance for clinical development.

Copies of the presentation slides will be made available on Epirium’s website, www.epirium.com and on LinkedIn following the conference presentations.

About MF-300

MF-300 is an investigational, orally bioavailable small molecule that reversibly occupies the prostaglandin E2 (PGE2) binding site of 15-hydroxyprostaglandin dehydrogenase (15-PGDH). 15-PGDH metabolically degrades PGE2, generating non-functional PGE2 metabolites, and is transcriptionally upregulated in aged muscle. Preclinical data show that PGE2 plays a crucial role in promoting aged muscle strength by improving muscle quality (i.e., muscle strength independent of muscle mass) as well as function of the neuromuscular junction. In preclinical studies, oral administration of MF-300 increases physiologic levels of PGE2 in skeletal muscle in rats and it increases muscle force and improves muscle quality in aged mice. Inhibiting 15-PGDH in aged muscle may be a strategy to increase physiologic levels of PGE2 to improve muscle quality and function in sarcopenia.

About Sarcopenia

The U.S. Food and Drug Administration (FDA) estimates that up to a third of Americans over the age of 60 are affected by sarcopenia, a disease that increases the risk of falls, fractures, disability and all-cause mortality. Despite sarcopenia’s widespread prevalence and serious health implications, there are currently no FDA-approved therapies available to treat sarcopenia, highlighting the significant unmet medical need for this disease.

About Epirium Bio

Epirium, a clinical-stage biopharmaceutical company based in San Diego, California, has identified and established an IP-protected platform of orally bioavailable small molecules that constitute a new class of therapeutics with the potential to improve function in neuromuscular diseases, including sarcopenia and spinal muscular atrophy. Epirium has generated preclinical data in a broader scope of indications with significant unmet medical need, including fibrosis, which Epirium’s development pipeline has the potential to address.

To learn more about Epirium, please visit www.epirium.com and follow us on LinkedIn.

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