(Reuters) - Sophiris Bio Inc said interim data showed that its only pipeline compound did not meet a predetermined threshold for efficacy in treating lower urinary tract symptoms of enlarged prostate.

The stock fell 67 percent to 93 cents in premarket trading.

The drug developer said the ongoing late-stage study of the drug was "unaffected" by the data and that the final analysis of the data was expected in the fourth quarter of 2015.

The main goal of the study was a reduction in symptoms measured by an eight-question screening tool called International Prostate Symptom Score (IPSS).

(Reporting by Vidya L Nathan in Bengaluru; Editing by Savio D'Souza)