# Endoscopic-mediated hydrodynamic gene therapy for hemophilia B through the biliary system

> **NIH NIH R21** · JOHNS HOPKINS UNIVERSITY · 2021 · $1

## Abstract

Gene therapy has been explored for cure of hemophilia, but declining expression levels of clotting
factors from AAV vectors in clinical trials over-time represents a significant limitation. For hemophilia
B, the long-term goal is to establish a redosable gene therapy that could maintain human Factor IX
(hFIX) production throughout a patient’s lifetime. The overall objective is to use bioengineering
principles to develop a non-viral, hydrodynamic strategy in large animals that would not be limited by
any neutralizing capsid antibodies or T cell responses hampering AAV vectors. The central
hypothesis is that an endoscopic procedure mediating hydrodynamic injection through the biliary
system could mediate effective delivery system for hFIX into the liver of large animals with clinically
relevant expression. The rationale is that biliary system effectively contacts all hepatocytes, while
possessing much less intrahepatic volume than the vascular system (30 mL vs. 600 mL), avoiding
limitations of previous, inefficient vascular hydrodynamic delivery approaches with balloon catheters.
The hypothesis is supported by preliminary studies in pigs, which show that the procedure is well-
tolerated with hepatocyte transfection levels exceed AAV transduction levels in the liver of primates.
The central hypothesis will be tested by pursuing two specific aims: 1) Safety and parameters of
biliary hydrodynamic injection will be evaluated to address concerns over physiologic disturbance.
Maximum volumes and flow rates during endoscopic injection will be tested to understand tolerability,
followed by correlation of these parameters and fluid pressure with reporter gene expression.
Biochemical and hematologic side effects will be examined during plasmid DNA injection, and
distribution of plasmid DNA within the liver and other pig tissues will be assessed to categorize off-
target risks. 2) hFIX gene therapy will be optimized for therapeutic levels against hemophilia B. hFIX
DNA will be injected through biliary hydrodynamic delivery in pigs and expression levels quantified.
The percentage of pig hepatocytes expressing hFIX and their localization within the liver lobule will be
assessed. Biliary hydrodynamic injection will also be modeled in non-human primates to assess
tolerability in this animal model, with goal of achieving similar hFIX plasma levels to AAV vectors in
primates. Repeated hydrodynamic injection of hFIX pDNA vector will be performed to increase hFIX
levels and validate redosing. The research proposal is innovative, in the applicant’s opinion, because
hydrodynamic delivery was thought to be clinically unfeasible and inefficient in large animals versus
viral vectors, so this research solves this major gap. The proposed research is significant because
non-viral, plasmid based gene therapy is safer and magnitudes less expensive than viral vectors,
paving the way for redosable gene therapy for other monogenic liver diseases beyond hemophilia.

## Key facts

- **NIH application ID:** 10287682
- **Project number:** 1R21HL159561-01
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Vivek Kumbhari
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $1
- **Award type:** 1
- **Project period:** 2021-09-01 → 2021-09-02

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10287682

## Citation

> US National Institutes of Health, RePORTER application 10287682, Endoscopic-mediated hydrodynamic gene therapy for hemophilia B through the biliary system (1R21HL159561-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10287682. Licensed CC0.

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