(Reuters) - Drug developer Clearside Biomedical Inc said on Monday its treatment helped improve vision in patients with fluid buildup in the eye in a late-stage study, sending its shares surging 54.1 percent in premarket trading.

The company said 47 percent of patients being administered its treatment, suprachoroidal CLS-TA, could see at least 15 letters, compared to 16 percent for patients who underwent a placebo procedure.

Clearside said it expected to file a marketing application with U.S. regulators in the fourth quarter.

The drug was being tested in patients with macular edema associated with an inflammation of a part of the eye known as uveitis.

Macular edema is the buildup of fluid in the part of the eye known as macula, resulting in distorted vision.

Clearside said detailed results from the study would be presented at an upcoming medical conference.