# Planning study for a phase-2 randomized multi-center placebo-controlled treatment trial of retinitis pigmentosa

> **NIH NIH R34** · JOHNS HOPKINS UNIVERSITY · 2021 · $238,256

## Abstract

ABSTRACT
 Retinitis Pigmentosa (RP) is a group of inherited retinal diseases resulting from one or more of a large
number of genetic mutations. It is a major cause of blindness and severe vision loss in people aged 20-60 years.
The first symptom is loss of night vision as a result of mutation-caused death of rod photoreceptors.
Subsequently loss of cone photoreceptors begins, and patients experience gradual loss of visual field until
become legally blind. Currently, there is no treatment for preventing vision loss in RP. Mechanistic studies
have shown that death of rods results in elevated tissue-level of oxygen in the outer retina. Exposure to the
excessive oxidative stress leads to progressive damage and death of the cone cells. Therefore, reducing
oxidative stress in cones can be a viable therapeutic target for preserving cones in RP, and potent antioxidants
are thought to promote cone survival and function in patients with RP. Cones provide vision under photopic
lighting which is critical for daily activities, thus preventing cone degeneration can prevent visual disability and
blindness in patients with RP. N-Acetylcysteine (NAC) is a well-known antioxidant and available as a generic
medication for treatment of acetaminophen overdose and as a dietary supplement. Animal studies reported
that orally administered NAC reduced cone cell death and preserved cone function by reducing oxidative
damage in two mice models of RP. A recent phase-1 open label dose-ranging study enrolled 30 RP patients and
followed them for 6-months at the Wilmer Eye Institute (clinicaltrial.gov NCT03063021). The study
demonstrated that oral NAC was safe and that dosages up to 1800mg/bid were well tolerated in patients with
RP. A multicenter, randomized, placebo-controlled phase-2 clinical trial therefore is warranted to determine
the safety and efficacy of long-term NAC treatment in slowing progression of RP. Support is being requested
for the planning of the multicenter phase-2 trial, to 1). Develop a manual of procedures, data collection forms,
and other materials required to conduct the phase-2 trial; 2).Develop procedures for the trial Coordinating
Center and the resource centers, including an Image Reading Center, the drug acquisition and distribution
center, and the central chemistry laboratory; 3). Create an organizational structure to facilitate, guide, conduct,
and monitor the multicenter study; and 4). Further refine the design of the phase-2 trial through incorporating
information generated from the ongoing extension study of the phase-1 dose-ranging study participants and a
study of the natural history of RP. Procedures and materials developed from this planning grant will ensure
successful conduct of the phase -2 trial to achieve the specific aims of 1). Evaluating the rates of anatomic and
functional changes over 24-months in RP patients receiving 1200mg bid or 1800mg bid oral NAC compared to
patients receiving placebo; and 2) determining an efficacious dosa...

## Key facts

- **NIH application ID:** 10142481
- **Project number:** 5R34EY031429-02
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Peter A Campochiaro
- **Activity code:** R34 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $238,256
- **Award type:** 5
- **Project period:** 2020-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10142481

## Citation

> US National Institutes of Health, RePORTER application 10142481, Planning study for a phase-2 randomized multi-center placebo-controlled treatment trial of retinitis pigmentosa (5R34EY031429-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10142481. Licensed CC0.

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