Eflepedocokin alfa

Summary

Eflepedocokin alfa (UTTR1147A) is an investigational recombinant fusion protein that links human interleukin‑22 to the Fc fragment of IgG4. Designed to activate the IL‑22 receptor on epithelial cells, it is being explored for conditions characterized by epithelial injury such as inflammatory bowel disease and liver disease. Early‑phase human studies have examined intravenous and subcutaneous dosing, focusing on safety, pharmacokinetics, and biomarker activation.

Mechanism of Action

The IL‑22 domain of eflepedocokin alfa binds the heterodimeric IL‑22 receptor complex expressed on epithelial tissues. This engagement triggers STAT3 phosphorylation, leading to transcription of genes that reinforce barrier integrity, stimulate antimicrobial peptide production (e.g., REG3A/B), and promote epithelial proliferation and wound healing. The Fc portion extends systemic half‑life and reduces effector functions, allowing sustained pathway activation.

What the Research Shows

Preclinical work demonstrated STAT3 activation by eflepedocokin alfa across human, monkey, minipig, rat, and mouse hepatocytes, with predictable epidermal hyperplasia and acute‑phase protein rises. In mouse colitis models, the protein reduced histologic inflammation and increased REG3β and serum amyloid A levels. A Phase I placebo‑controlled trial in healthy volunteers showed dose‑proportional exposure, a ~1‑week half‑life, and reversible skin effects, with biomarker elevations (REG3A, SAA, CRP). A Phase 1b study in ulcerative colitis patients confirmed IL‑22 pathway activation in colon biopsies, altered gut microbiota toward normal, and exploratory clinical response/remission in a subset of participants. A 2025 review highlighted favorable safety and early efficacy signals in alcohol‑associated liver disease models, but emphasized the need for larger trials.

Reported Benefits

Evidence suggests eflepedocokin alfa can stimulate epithelial regeneration, improve barrier function, and induce antimicrobial peptides, offering a non‑immunosuppressive approach to diseases like ulcerative colitis and potentially liver injury. Early human data show target engagement and modest clinical improvements without systemic inflammation, supporting its therapeutic promise for epithelial‑driven disorders.

Limitations of the Evidence

Current data are limited to preclinical models and early‑phase (I/Ib) studies with small cohorts; efficacy has not been confirmed in larger, controlled trials. Dermatologic adverse events become dose‑limiting at higher exposures, and drug exposure differed between healthy volunteers and patients, indicating variability. Long‑term safety and benefit‑risk balance remain unknown.

Safety Considerations

Most adverse events were mild to moderate and reversible, primarily skin‑related (dry skin, erythema, pruritus, occasional exfoliation) occurring in a dose‑dependent manner. No increase in systemic inflammatory cytokines was observed. Transient rises in acute‑phase proteins were noted but considered predictable. The maximum tolerated intravenous dose in healthy volunteers was 90 µg/kg, and the overall safety profile was judged acceptable for further study.

How It Is Administered

Eflepedocokin alfa is formulated for intravenous infusion or subcutaneous injection. Clinical studies have used single ascending doses (1–120 µg/kg IV; 3–120 µg/kg SC) and repeat dosing every two or four weeks in phase 1b trials. The Fc fusion confers an approximate one‑week half‑life, supporting less frequent dosing schedules.

Routes of Administration

Goals & Uses

• Alcoholic hepatitisHepatologyLow
• Mucositis (chemotherapy-induced)Oncology Supportive CareLow
• Graft-versus-host disease (GvHD) treatmentImmunology / TransplantModerate
• Intestinal epithelial repairGastroenterologyModerate
• Inflammatory bowel diseaseGastroenterologyLow

Contraindications

• Known hypersensitivity to eflepedocokin alfa or Fc fusion proteinsAllergy/ImmunologyHigh
• Active malignancy with STAT3-driven tumor proliferationOncologyModerate
• Severe uncontrolled infectionInfectionModerate

Adverse Effects

• Psoriasiform skin lesionsDermatologicRare
• Injection site reactionsLocalCommon
• NauseaGastrointestinalCommonFeeling of sickness or urge to vomit
• FatigueGeneralCommonLow energy or tiredness
• Elevated liver enzymes (transaminases)HepaticUncommon
• Infusion-related reactionsHypersensitivityUncommon

Drug Interactions

• Immunosuppressants (e.g., tacrolimus, cyclosporine)Moderate
• CorticosteroidsLow

Population Constraints

• Pediatric patientsAgeRelative
• Pregnant womenReproductiveRelative
• Severe hepatic impairmentOrgan ImpairmentRelative
• Patients with active colorectal or pancreatic cancerOncologyRelative

Regulatory Status

• European UnionInvestigationalNo EMA approval; clinical trials conducted in EU sites.
• United StatesInvestigationalUnder clinical investigation; no FDA approval. Orphan Drug Designation explored for GvHD.
• United KingdomInvestigationalNo MHRA approval; no separate UK regulatory designation confirmed.

Not approved by FDA, EMA, or other major regulatory agencies. Investigated in multiple Phase I/II clinical trials. Orphan Drug Designation has been explored for GvHD indications.

Evidence & Sources

• Identification of an IL-22-Dependent Gene Signature as a Pharmacodynamic Biomarker
  Journal ArticleLowRae J, et al.2021-01-01T00:00:00.000000Z
• Nonclinical safety assessment of a human interleukin-22FC IG fusion protein demonstrates in vitro to in vivo and cross-species translatability
  Journal ArticleLowLee DW, et al.2018-01-01T00:00:00.000000Z
• Pre-clinical and translational pharmacology of a human interleukin-22 IgG fusion protein for potential treatment of infectious or inflammatory diseases
  Journal ArticleLowStefanich EG, et al.2018-01-01T00:00:00.000000Z
• Randomized Phase I Healthy Volunteer Study of UTTR1147A (IL-22Fc): A Potential Therapy for Epithelial Injury
  Journal ArticleModerateRothenberg ME, et al.2019-01-01T00:00:00.000000Z
• An Update on IL-22 Therapies in Alcohol-Associated Liver Disease and Beyond
  Journal ArticleModerateFu L, et al.2026-01-01T00:00:00.000000Z
• Dose escalation randomised study of efmarodocokin alfa in healthy volunteers and patients with ulcerative colitis
  Journal ArticleModerateWagner F, et al.2023-01-01T00:00:00.000000Z

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