Mecobalamin Combined With Anti-VEGF Intravitreal Injection for Retinal Vein Occlusion Treatment

NCT07133438 | Recruiting Phase 4

• 1 other identifier: No. 2025-387-01
• Study Type: interventional
• Target: 120
• Locations: 1 country
• Sites: 1

Brief Summary

Retinal vein occlusion (RVO), a common retinal vascular disease, is frequently treated with anti-vascular endothelial growth factor (anti-VEGF) agents as first-line therapy. However, anti-VEGF monotherapy lacks neuroprotective effects, primarily targets vascular leakage and neovascularization, and requires frequent long-term injections that impose substantial economic burdens. Combined therapeutic strategies addressing both vascular pathology and neural damage are therefore being explored. This article describes the protocol for a randomized, outcome-blinded, placebo-controlled clinical trial evaluating mecobalamin (a widely used neuroprotective drug) in combination with anti-VEGF for the treatment of macular edema (ME). A total of 120 eligible RVO patients will be enrolled from the First Affiliated Hospital of Chongqing Medical University. Participants will be randomly assigned (1:1) to an experimental group and a control group. The experimental group will receive conventional anti-VEGF therapy plus oral mecobalamin capsules for 6 months, while the control group will receive the same anti-VEGF treatment plus a placebo for 6 months. All patients will undergo one year of follow-up after initial treatment, with visits at 1, 3, 6, 9, and 12 months. The primary outcome is the change in central subfield thickness (CST) from baseline to one year post-initial treatment. Secondary outcomes include:

• Change in best-corrected visual acuity (BCVA) from baseline over time,
• Capillary density,
• Cone photoreceptor distribution characteristics,
• Mean light sensitivity and fixation stability,
• Serum vitamin B12 levels,
• Number of anti-VEGF treatments,
• Injection frequency (times per year),
• Treatment interval,
• Incidence and severity of adverse events (AEs) and serious adverse events (SAEs). This trial evaluates a novel "neuroprotection + vascular intervention" strategy combining mecobalamin with anti-VEGF therapy. The trial aims to provide high-level evidence for synergistic RVO treatment, with the potential to reduce recurrence rates and improve long-term visual function prognosis.

Conditions

Retinal Vein Occlusion (RVO)

Keywords

Retinal Vein Occlusion (RVO); Macular edema; Anti-VEGF

Outcome Measures

Primary Outcomes (1)

• Anatomical indicators-central foveal thickness

  the changes in central foveal thickness from baseline to 1 year post initial treatment.The primary outcome is the change in central subfield thickness (CST), measured via spectral-domain optical coherence tomography (SD-OCT), from baseline to 12 months post-initial treatment. CST will be defined as the mean retinal thickness within the central 1-mm diameter subfield of the ETDRS grid (Early Treatment Diabetic Retinopathy Study), automatically segmented and calculated using device software (e.g., Heidelberg Spectralis® or equivalent). All OCT scans will be performed by certified technicians following standardized protocols, including quality control for signal strength (\>7/10), proper centering, and absence of artifacts. Measurements will be verified by masked graders at a central reading center.

  From enrollment to the end of treatment at 1 year

Secondary Outcomes (8)

• Change in best-corrected visual acuity (BCVA)

  From enrollment to the end of treatment at 1 year

• capillary density

  From enrollment to the end of treatment at 1 year

• Cone photoreceptor distribution characteristics

  From enrollment to the end of treatment at 1 year

• Mean light sensitivity and fixation stability

  From enrollment to the end of treatment at 1 year

• Serum vitamin B12 levels

  From enrollment to the end of treatment at 1 year

Study Arms (2)

experimental group

EXPERIMENTAL

Patients in the experimental group will receive conventional anti-VEGF therapy (intravitreal injections of conbercept 0.5 mg initially once a month for 3 months, followed by on-demand therapy which based on recurrence criteria) along with oral mecobalamin capsules 0.5 mg three times daily for 6 months.

Drug: Anti-VEGF drug; Drug: Mecobalamin 5 MG

control group

PLACEBO COMPARATOR

Patients in the control group will receive the same anti-VEGF treatment as the experimental group and will take a placebo capsule with a similar appearance and odor to the mecobalamin capsules three times daily for 6 months

Drug: Anti-VEGF drug; Drug: Placebo

Interventions

Anti-VEGF drug DRUG

conventional anti-VEGF therapy (intravitreal injections of conbercept 0.5 mg initially once a month for 3 months, followed by on-demand therapy which based on recurrence criteria)

control group; experimental group

Mecobalamin 5 MG DRUG

oral mecobalamin capsules 0.5 mg three times daily for 6 months

experimental group

Placebo DRUG

placebo capsule with a similar appearance and odor to the mecobalamin capsules three times daily for 6 months

control group

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Diagnosis of RVO meeting the international diagnostic criteria 4,12, age 18-80 years, gender not limited Treatment-naive RVO-ME (no prior anti-VEGF, glucocorticoid, or laser therapy) The CST is confirmed to be ≥300μm by OCT The baseline BCVA (ETDRS letter count) was 20/400 to 20/40 (34-78 letters) Signed informed consent and ability to comply with follow-up.

You may not qualify if:

• Combined with other eye diseases that cause ME (such as diabetic retinopathy, uveitis) Media opacities affecting imaging (such as severe cataract, vitreous hemorrhage) Prior anti-VEGF, steroid, or macular laser therapy Systemic use of glucocorticoids or immunosuppressants within 3 months Uncontrolled systemic disease (hypertension, diabetes, hepatic/renal dysfunction); pregnant or lactating women Allergy to mecobalamin or conbercept Unable to cooperate with examinations or follow-up, or participate in other clinical trials within one year

Sponsors & Collaborators

• First Affiliated Hospital of Chongqing Medical University: lead

Study Sites (1)

No. 1, Friendship Road, Yuanjiagang, Yuzhong District, Chongqing City

Chongqing, 400016, China

RECRUITING

MeSH Terms

Conditions

Retinal Vein Occlusion; Macular Edema

Interventions

mecobalamin

Condition Hierarchy (Ancestors)

Retinal Diseases; Eye Diseases; Venous Thrombosis; Thrombosis; Embolism and Thrombosis; Vascular Diseases; Cardiovascular Diseases; Macular Degeneration; Retinal Degeneration

Central Study Contacts

Wen-Li Deng, doctoral

CONTACT

+8619823579019; dengwenli@hospital.cqmu.edu.cn

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: All study participants will be blinded to their intervention assignment. The drug and placebo were identical in packaging, appearance, and smell. Mecobalamin and placebo were assigned by an independent pharmacy according to random codes. Evaluators were blinded to group allocation. All study medications (active and placebo) will be identically labeled to ensure adequate blinding of study physicians and patients. Patients, principal investigators, assessor physicians, imaging technicians, central reading center graders, study coordinators, and BCVA examiners will be blinded to treatment assignment.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: associate chief physician

Model Details: a double-blind randomized controlled trial

Study Record Dates

• First Submitted: June 29, 2025
• First Posted: August 21, 2025
• Study Start: August 1, 2025
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): July 31, 2027
• Last Updated: February 27, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL
• Time Frame: Data will become available after the publication of the primary trial results and will be accessible for a reasonable period.
• Access Criteria: Data are available to researchers for legitimate scientific purposes. Accessible information includes de-identified participant data and supporting documents.Access is contingent upon submission of a research proposal and signing a Data Access Agreement.

Locations

CN (1)