One04 Therapeutics reports positive CPV-104 Phase 1 data in C3G

One04 Therapeutics has presented interim Phase 1 data for CPV-104, its recombinant full-length human Factor H therapy, at the American Society of Nephrology Kidney Week 2026 in Denver. The data, disclosed in a late-breaking poster, showed the candidate met predefined primary safety and secondary objectives and produced exploratory signals of biological activity in patients with C3 glomerulopathy (C3G).

The ongoing two-part study evaluated single ascending doses in 21 healthy volunteers across four cohorts and is continuing with multiple ascending doses in C3G patients across three cohorts totalling 18 participants. Interim results cover the first two of three planned multiple-dose cohorts, with dosing in the highest cohort at 15 mg/kg still ongoing at the time of announcement.

Safety and pharmacokinetics

CPV-104 was reported as generally well tolerated at doses up to 15 mg/kg in single-dose healthy volunteers and up to 7.5 mg/kg dosed weekly for four weeks in C3G patients. No serious adverse drug reactions, serious treatment-emergent adverse events, deaths or treatment discontinuations were recorded. No anti-drug antibodies were detected in evaluable samples, which is a meaningful early finding for a recombinant protein therapy given the immunogenicity risk that typically accompanies biologics of this class.

Pharmacokinetic parameters showed dose-proportional exposure, a terminal half-life of three to four days, and modest accumulation on a weekly dosing schedule. The company said this profile is consistent with a once-weekly intravenous regimen being taken forward into later evaluation.

Prof. Michael Wiesener of University Hospital Erlangen, the presenting author, noted the results "support continued clinical evaluation of CPV-104," while adding the standard caveat that the study involves a small number of patients and a short treatment period.

Exploratory analyses in multiple-dose C3G patients showed signals of proteinuria reduction at the 7.5 mg/kg dose level alongside stable estimated glomerular filtration rate, two markers that physicians and regulators typically track when assessing disease-modifying potential in chronic kidney disease settings.

Market context and competitive landscape

C3G is a rare, complement-mediated kidney disease with no approved disease-modifying therapy. It is driven by dysregulation of the alternative complement pathway, and patients frequently progress to end-stage renal disease. The condition sits within a broader wave of complement-targeted drug development that has gathered pace since the approval of eculizumab in related indications, and more recently with the emergence of oral Factor D and Factor B inhibitors from several mid-to-large pharma and biotech players targeting overlapping complement pathways.

CPV-104's positioning as a full-length recombinant Factor H is mechanistically distinct from antibody-based complement inhibitors currently in late-stage development or approved use. Factor H acts as an endogenous regulator of the alternative pathway, and the company argues a replacement approach could restore immune homeostasis rather than simply block downstream effectors. Whether that translates into a durable clinical advantage over inhibitor-based approaches remains to be established in larger, longer studies.

One04 is privately held and has not disclosed its funding position or a Phase 2 timeline. The company is hosting a virtual key opinion leader event on 26 October 2026 to discuss the data, featuring nephrologists from Amsterdam, Vienna, and Erlangen alongside a clinical pharmacology expert. The KOL roster suggests the company is actively cultivating relationships with European academic centres ahead of what is likely to be a multi-country Phase 2 programme. Investors and prospective partners will be watching for a named Phase 2 protocol and updated safety data from the ongoing highest-dose cohort.