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Effects of Treatment With N- Acetylcysteine on Visual Outcomes in Patients With Retinitis Pigmentosa

Primary Purpose

Retinitis Pigmentosa

Status
Unknown status
Phase
Phase 2
Locations
Iran, Islamic Republic of
Study Type
Interventional
Intervention
Prescribe N-acetylcysteine tablets
Prescribe placebo tablets
Sponsored by
Shahid Beheshti University of Medical Sciences
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Retinitis Pigmentosa

Eligibility Criteria

18 Years - 40 Years (Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

  • RP patients with the best-corrected visual acuity (BCVA) between 20/30 and 20/120.

Exclusion Criteria:

  • Patients with other types of retinal dystrophy
  • Systemic or syndromic RP
  • RP patients with cystoid macular edema (CME) and the presence of cystoid changes in the foveal area
  • RP patients with other concomitant ocular diseases
  • RP patients with a history of any ocular surgery or intravitreal injection within 6 months before the study enrollment
  • RP patients who have received any supplemental drugs during the past three months before the study enrollment

Sites / Locations

  • Ophthalmic Research Center

Arms of the Study

Arm 1

Arm 2

Arm Type

Active Comparator

Placebo Comparator

Arm Label

Prescribe N-acetylcysteine tablets

Prescribe placebo tablets

Arm Description

Outcomes

Primary Outcome Measures

Change of the best corrected visual acuity (BCVA) from baseline to month 6
ETDRS chart

Secondary Outcome Measures

Change of the ellipsoid zone (EZ) width from baseline to month 6
spectral domain optical coherence tomography (SD-OCT)
Changes of the wave amplitude of the flicker response from baseline to month 6
Full field electroretinograph (ffERG) testing
Change of the foveal and macular sensitivity from baseline to month 6
visual field testing
Change of the color discrimination parameters from baseline to month 6
D15 Fransworth 100 Hue Test

Full Information

First Posted
April 21, 2021
Last Updated
April 27, 2021
Sponsor
Shahid Beheshti University of Medical Sciences
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1. Study Identification

Unique Protocol Identification Number
NCT04864496
Brief Title
Effects of Treatment With N- Acetylcysteine on Visual Outcomes in Patients With Retinitis Pigmentosa
Official Title
Effects of Oral N- Acetylcysteine on Macular Function in Retinitis Pigmentosa; a Phase 2 Randomized Controlled Trial
Study Type
Interventional

2. Study Status

Record Verification Date
April 2021
Overall Recruitment Status
Unknown status
Study Start Date
April 17, 2021 (Actual)
Primary Completion Date
March 1, 2022 (Anticipated)
Study Completion Date
December 20, 2022 (Anticipated)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
Shahid Beheshti University of Medical Sciences

4. Oversight

Studies a U.S. FDA-regulated Drug Product
No
Studies a U.S. FDA-regulated Device Product
No

5. Study Description

Brief Summary
Retinitis pigmentosa (RP) is an inherited retinal disease with great heterogeneity. RP comprises a large group of genetic disorders causing progressive loss of vision. Despite many suggested treatments, there is actually no effective therapy for most types of RP at present. Mutations that cause RP initially lead to rod cell death. After rod photoreceptors' death, cone photoreceptors also gradually die. There are several hypotheses as to why mutation-induced rod photoreceptor cell death invariably leads to gradual dysfunction and death of cone photoreceptors resulting in severe visual acuity loss and blindness. Rods constitute 95 percent of cells in the outer retina. As they degenerate, oxygen consumption is reduced and the level of tissue oxygen markedly increases. After rods degeneration, several markers of oxidative damage appear in cones. This oxidative stress over time may lead to cone dysfunction and death. Antioxidants reduce markers of oxidative damage and promote cone function and survival. In RP, cone death occurs as a result of the death of rods, rather than as the result of the pathogenic mutations and therefore treatment with antioxidants may have the potential to be applied to all patients with RP irrespective of the disease-causing mutation. N-acetylcysteine is a derivative of L cysteine that plays a role in the biosynthesis of glutathione and neutralizes reactive oxygen species. It also has a direct antioxidant activity via its reactive sulfhydryl agent. Its systemic use shows an acceptable safety profile. It has been shown that the use of systemic N-acetylcysteine provides significant intraocular concentration and antioxidant activity that may lead to the promotion of cone function and survival. In a recent phase 1 randomized clinical trial (RCT), it was revealed that oral N-acetylcysteine (NAC) was safe and well-tolerated in patients with moderately advanced RP and might improve sub-optimally functioning macular cones. The authors concluded that a randomized, placebo-controlled trial is needed to determine if oral NAC can provide long-term stabilization and/or improvement in visual function in patients with RP. In this phase 2 RCT, eligible patients with the diagnosis of moderately advanced RP are randomly divided into two groups; treatment group (N-acetylcysteine tablets) and controls (placebo). Each group will be treated for 6 months. In this study, we will investigate if the use of oral N- acetylcysteine as a potent antioxidant agent can slow down or reverse the disease process in RP patients with prior moderate loss of vision. It may potentially demonstrate a treatment modality regardless of the genetic type of RP. The primary outcome measure will be the stability or improvement of the best-corrected visual acuity (BCVA). The secondary outcome measures will be changes in color vision, electroretinogram, visual field, structural OCT indices after 6 months. The same parameters will be re-evaluated 3 months after discontinuation of treatment at month 9.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Retinitis Pigmentosa

7. Study Design

Primary Purpose
Treatment
Study Phase
Phase 2
Interventional Study Model
Parallel Assignment
Masking
ParticipantCare ProviderInvestigatorOutcomes Assessor
Allocation
Randomized
Enrollment
30 (Anticipated)

8. Arms, Groups, and Interventions

Arm Title
Prescribe N-acetylcysteine tablets
Arm Type
Active Comparator
Arm Title
Prescribe placebo tablets
Arm Type
Placebo Comparator
Intervention Type
Drug
Intervention Name(s)
Prescribe N-acetylcysteine tablets
Intervention Description
N-acetylcysteine tablets ,1200 mg two times daily
Intervention Type
Drug
Intervention Name(s)
Prescribe placebo tablets
Intervention Description
manufactured by Daroo Salamat Pharmed, two times daily
Primary Outcome Measure Information:
Title
Change of the best corrected visual acuity (BCVA) from baseline to month 6
Description
ETDRS chart
Time Frame
6 months
Secondary Outcome Measure Information:
Title
Change of the ellipsoid zone (EZ) width from baseline to month 6
Description
spectral domain optical coherence tomography (SD-OCT)
Time Frame
6 months
Title
Changes of the wave amplitude of the flicker response from baseline to month 6
Description
Full field electroretinograph (ffERG) testing
Time Frame
6 months
Title
Change of the foveal and macular sensitivity from baseline to month 6
Description
visual field testing
Time Frame
6 months
Title
Change of the color discrimination parameters from baseline to month 6
Description
D15 Fransworth 100 Hue Test
Time Frame
6 months

10. Eligibility

Sex
All
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
40 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: RP patients with the best-corrected visual acuity (BCVA) between 20/30 and 20/120. Exclusion Criteria: Patients with other types of retinal dystrophy Systemic or syndromic RP RP patients with cystoid macular edema (CME) and the presence of cystoid changes in the foveal area RP patients with other concomitant ocular diseases RP patients with a history of any ocular surgery or intravitreal injection within 6 months before the study enrollment RP patients who have received any supplemental drugs during the past three months before the study enrollment
Facility Information:
Facility Name
Ophthalmic Research Center
City
Tehran
Country
Iran, Islamic Republic of

12. IPD Sharing Statement

Learn more about this trial

Effects of Treatment With N- Acetylcysteine on Visual Outcomes in Patients With Retinitis Pigmentosa

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