RJB-0402 uses gene delivery to the liver as a proposed way to influence the heart. Rejuvenate Bio's named human programme focuses on arrhythmogenic cardiomyopathy, including disease associated with desmoplakin variants.
The programme illustrates a delivery question in biotechnology: can a tissue that is accessible to a vector manufacture a protein whose effects occur elsewhere? The eventual clinical test would need to establish the protein exposure, disease effect and safety together.
CIRM announced a $4 million preclinical award in 2024. Its current grant page lists a closed award valued at $570,000. The checked pages do not explain the change. A closed grant does not establish that the company abandoned the programme.
- AAV targets liver cellsThe payload encodes FGF21.
- Produce a circulating signalEffects can extend beyond the liver.
- Test cardiac outcomesDisease model, duration and endpoints remain explicit.
The reported PKP2 mouse model and the intended DSP programme are different records. Sources for this account.
The mechanism
The CIRM public abstract describes an adeno-associated virus vector targeting hepatocytes and driving expression of FGF21. Hepatocytes are liver cells. FGF21 is a signalling protein with effects beyond the tissue that secretes it.
The approach does not replace a defective DSP gene in each heart cell. It proposes changing downstream disease processes through a circulating signal. The application names several planned activities before human testing, including nonclinical work and manufacturing.
A 2026 paper examined AAV8-mediated FGF21 delivery in adult mice with a cardiac PKP2 knockout. PKP2 and DSP are different genes, although both appear in arrhythmogenic cardiomyopathy research. The mouse result should therefore retain its own model description when it is discussed beside the intended DSP programme.
The study reported changes in cardiac structure, arrhythmias and calcium handling. An acute one-hour exposure in cultured cells did not produce the same calcium effect. Time, delivery route and the disease model are part of the mechanism question.
Human evidence
No human interventional start or human efficacy publication for RJB-0402 was verified in the sources checked. The company pipeline continues to list Human-RJB-0402, while CIRM's abstract describes preparation for an IND submission and a proposed first human trial.
Evidence about FGF21 proteins or analogues in other clinical programmes cannot be assigned wholesale to this vector. A gene therapy introduces a different exposure pattern and its own manufacturing, immune and durability questions.
Studies and experimental evidence
FGF21 in PKP2 arrhythmogenic cardiomyopathy
- Design
- AAV8 gene-delivery experiments and cellular physiology
- Population or model
- Adult cardiac-specific PKP2 knockout mice and isolated cells
- Sample size
- Multiple assays; no pooled sample verified
- Comparison
- Model controls; acute FGF21 cell exposure also examined
- Duration
- Varies by experimental assay
- Outcome
- Cardiac structure, arrhythmias and intracellular calcium
Paper reports reduced adrenergic arrhythmias and improved calcium handling
Mouse genetic model; PKP2 differs from the programme's DSP indication; no human outcome
Funding and interests: Company employees and consultants report salary/equity interests
RJB-0402 IND-enabling project
- Design
- Preclinical development plan
- Population or model
- Proposed DSP-related arrhythmogenic cardiomyopathy programme
- Sample size
- Not a human results dataset
- Comparison
- Not applicable
- Duration
- Not reported
- Outcome
- Nonclinical package, manufacturing and trial preparation
Public grant record documents planned activities
An award abstract reports a plan, not completed efficacy work
Funding and interests: CIRM; current record differs from original announced award
Development history
Preclinical support announced
CIRM announced an award supporting development of RJB-0402.
PKP2 model paper published online
The FGF21 vector study reported cardiac and calcium findings in mice.
Unresolved questions
- What explains the change between CIRM's announced award and the current closed grant record?
- Has an IND been submitted or cleared for this specific vector and indication?
- What protein exposure can the vector sustain, and how variable is it across recipients?
- How well do PKP2 model findings predict outcomes in DSP-related disease?
- What endpoints would establish disease modification in an initial human study?
CIRM's public abstract identifies an IND submission as the project objective. No confirmed submission or clinical start date was found. A regulator or registry record would need to confirm a clinical start, with a protocol stating the indication and outcomes.
Sources
- Institutional source · 2024-06CIRM awards $26 million to advance clinical research
Original $4m preclinical award announcement.
Checked 4 Oct 2026 - Institutional source · UndatedCIRM grant CLIN1-16244
Current grant record: Closed, $570,000; mechanism and planned objective.
Checked 4 Oct 2026 - Paper · 26 Feb 2026Fibroblast growth factor 21 prevents catecholaminergic arrhythmias in a mouse model of PKP2 arrhythmogenic cardiomyopathy
Preclinical study, online date; journal issue August 2026.
Checked 4 Oct 2026 - Company disclosure · UndatedRejuvenate Bio pipeline
Lists Human-RJB-0402.
Checked 4 Oct 2026 - Company disclosure · UndatedRejuvenate Bio science and publications
Explains liver-directed approach and links research.
Checked 4 Oct 2026
Dr T Smith, organic chemist and science educator. Review date: 4 Oct 2026. Report a correction.