Drugmaker pSivida Corp said its lead experimental therapy prevented inflammation in the back of patients' eyes in a late-stage study.

The company's shares were up 27 percent at $4.70 in premarket trading on Tuesday.

The drugmaker said only 18.4 percent of the patients given the treatment Medidur had the condition, posterior uveitis, return, compared with 78.6 percent patients who were given the placebo.

Medidur is an implant that releases corticosteroid directly in the eye over a period of three years.

The company said 2.3 percent patients who were given Medidur in the 126-patient study had to be operated on to reduce the pressure in the eye.

PSivida plans to conduct a second late-stage study on Medidur. If the second study is successful, the drugmaker said it expects to file for marketing application in the first half of 2017.