One intravitreal bevacizumab injection improved trabeculectomy survival at three years

Design

Single-centre, double-masked, randomised placebo-controlled trial

Population

131 patients having trabeculectomy or phacotrabeculectomy with mitomycin C

Primary outcome

Trabeculectomy survival (complete and qualified success) at 36 months

Effect

HR 0.17 for loss of complete success (p=0.002); HR 0.07 for qualified (p=0.03)

This single-centre, double-masked, placebo-controlled trial randomised 131 patients having primary or repeat trabeculectomy or phacotrabeculectomy with mitomycin C to a single intraoperative intravitreal injection of bevacizumab 1.25 mg or balanced salt solution. Published in May, it reports three-year results, with 85% completing follow-up.

At 36 months, trabeculectomy survival was higher with bevacizumab, with a hazard ratio of 0.17 (p=0.002) for losing complete success and 0.07 (p=0.03) for losing qualified success. The placebo group needed topical drops more often at 3, 6, 12 and 36 months.

Scarring is the main reason trabeculectomies fail, and anti-VEGF agents may reduce the new vessel growth that drives it. A single injection at the end of surgery is simple and bevacizumab is widely available and low cost in India. But this is one centre, the abstract does not report absolute success rates, and intravitreal injection carries its own small risks. Larger multicentre trials should confirm the result before it becomes standard.

• Consider intraoperative intravitreal bevacizumab as an adjunct to mitomycin C in trabeculectomy, particularly in eyes at high risk of scarring.
• Discuss the added small risks of intravitreal injection, including endophthalmitis, with the patient.
• Use aseptic intravitreal injection technique as for any anti-VEGF injection.
• Continue mitomycin C as the standard antifibrotic; bevacizumab was tested as an addition, not a replacement.

Why it matters

A cheap, widely available drug given once could improve the durability of the operation that remains the workhorse of glaucoma surgery in India.

Don't overread it

A single-centre trial without reported absolute success rates is not enough to make this standard practice yet.

The statistics, in plain English

A hazard ratio of 0.17 means a much lower rate of failure over time with bevacizumab, but in a trial of 131 patients the true effect could be considerably smaller. The very low ratio for qualified success comes with a wide margin of uncertainty, and the abstract does not give absolute success rates to judge clinical size.

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