A Multicenter, Randomized, Double-Blind, Controlled Clinical Study of Minocycline for the Treatment of Retinitis Pigmentosa

NCT ID: NCT07082855

Last Updated: 2025-07-24

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: PHASE3
• Total Enrollment: 126 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-07-15
• Study Completion Date: 2028-06-30

Brief Summary

This is a multicenter, double-blind, randomized controlled clinical trial to get high - level evidence on minocycline's efficacy and safety（100mg/d, 200mg/d) for Retinitis pigmentosa and to find the optimal treatment dose.

Detailed Description

Retinitis pigmentosa (RP) is a major blinding eye disease, with a global prevalence of 1/9000-1/850. It's estimated that over 1.5 million Chinese people may have RP. Its typical clinical features are night blindness and progressive tunnel vision. In the disease's end stage, total loss of peripheral and central vision may occur, accounting for about 20% of all blinding causes. The main characteristic of RP is the progressive apoptosis of retinal photoreceptor cells, which leads to gradually worsening night blindness, concentric visual field constriction, and decreased visual acuity, among other visual function impairments.

The core of RP treatment is to slow down the progression of visual impairment and delay disease advancement. However, currently there are no effective clinical methods or recommended medications to control or slow RP's progression. In recent years, advanced therapies like gene therapy and stem cell treatments have been tried for RP but are still far from clinical application due to technical challenges. So, there's an urgent need for more accessible, widely applicable, and economical treatments.

RP has a complex and poorly understood etiology. Microglia, key resident macrophages in the central nervous system, when activated, can promote neurodegenerative diseases like RP. Suppressing this activation may slow disease progression. Minocycline, a tetracycline antibiotic with anti-inflammatory and immunomodulatory effects, can cross the blood - brain barrier and protect neurons by inhibiting microglial activation. It's been studied for treating neurodegenerative diseases such as Alzheimer's and Huntington's disease. A randomized controlled trial published in The New England Journal of Medicine in 2017 found that 6 months of 200mg daily minocycline for clinically isolated syndrome patients reduced their conversion rate to multiple sclerosis, showing minocycline's potential in neurodegenerative disease treatment. Safety studies indicate no antibiotic resistance after 36 months of 200mg daily minocycline used in geographic atrophy in age-related macular degeneration.

Our team completed a pilot study on minocycline for RP. The results showed that 12 months of 100mg daily minocycline improved RP patients' visual function with good tolerability.

Based on this, we plan a multicenter, randomized, double-blind, controlled clinical trial to get high - level evidence on minocycline's efficacy and safety for RP.

Conditions

Retinitis Pigmentosa; Inherited Retinal Dystrophy; Retina Disorder

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

Minocycline 100mg

Capsules Minocycline 100mg po once in the morning and placebo 100mg po once in the evening for 12 months

Group Type: EXPERIMENTAL

Minocycline 100mg

Intervention Type: DRUG

Capsules Minocycline 100mg po per day and placebo 100mg po per day for 12 months

Minocycline 200mg

Capsules Minocycline 100mg po twice a day for 12 months

Group Type: EXPERIMENTAL

Minocycline 200mg

Intervention Type: DRUG

Capsules Minocycline 100mg po twice a day for 12 months

Placebo

Capsules placebo 100mg po twice a day for 12 months

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DRUG

Capsules placebo 100mg po twice a day for 12 months

Interventions

Minocycline 100mg

Capsules Minocycline 100mg po per day and placebo 100mg po per day for 12 months

Intervention Type: DRUG

Minocycline 200mg

Capsules Minocycline 100mg po twice a day for 12 months

Intervention Type: DRUG

Placebo

Capsules placebo 100mg po twice a day for 12 months

Intervention Type: DRUG

Other Intervention Names

MRP intervention 1; MRP intervention 2; MRP control

Eligibility Criteria

Inclusion Criteria

• Age should be between 18 and 60 years old.
• Clinically diagnosed with retinitis pigmentosa, characterized by reduced electroretinogram (ERG) responses and constricted visual fields.
• In at least one eye, the amplitude of the 30Hz flicker ERG under photopic conditions should not be lower than 0 microvolts.
• The best-corrected visual acuity (BCVA, ETDRS) in both eyes should not be lower than 0.

Exclusion Criteria

• Allergic to tetracycline antibiotics.
• Pregnant or breastfeeding.
• Syndromic retinitis pigmentosa.
• Currently taking tetracycline antibiotics or any medications that may have adverse interactions with minocycline.
• Currently participating in or having participated in another investigational study within the past 6 months.
• Presence of other ocular diseases, including glaucoma, uveitis, age-related macular degeneration, diabetic retinopathy, etc.
• History of ocular surgical intervention.
• History of uncontrolled severe comorbid conditions, such as renal disease, liver disease, autoimmune disease, thyroid dysfunction, psychiatric disorders, or idiopathic intracranial hypertension.
• Inability of the participant to comply with the study-required procedures, such as epilepsy, inability to fixate, or allergy to fluorescein. Inability to understand the content of the study, sign the informed consent form, or comply with the study procedures or follow-up visits.
• Inability to swallow capsules.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Zhongshan Ophthalmic Center, Sun Yat-sen University

OTHER

Sponsor Role: lead

Responsible Party

Liang Dan

Zhongshan Ophthalmic Center

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Zhongshan Ophthalmic Center, Sun Yat-sen University

Guangzhou, Guangdong, China

Countries

China

Central Contacts

Dan Liang, Professor

Role: CONTACT

liangdan@gzzoc.com

0086-020-87330402

Facility Contacts

Dan Liang, Professor

Role: primary

liangdan@gzzoc.com

0086-020-87330402

Other Identifiers

MRP

Identifier Type: -

Identifier Source: org_study_id