Swiss drugmaker Novartis has withdrawn an application for European approval of its Xiidra dry eye medicine after regulators concluded its effectiveness had not been demonstrated and that its benefits did not outweigh risks.

Novartis bought Xiidra from Takeda last year for $3.4 billion up front and $1.9 billion in potential milestone payments to refresh its eye drug portfolio. The drug is approved in the United States where it posted $90 million in first-quarter sales, and Novartis Chief Executive Vas Narasimhan had said he would explore approval elsewhere.

Before Novartis's withdrawal was announced on Friday, the European Medicines Agency (EMA) said it had already concluded that the Basel-based company had not shown that the medicine worked and raised concerns that Xiidra could not be authorized.

"The effectiveness of Xiidra was not demonstrated across different symptoms of dry eye disease," the EMA said on its website. "Although some effect was seen in the reduction of eye dryness, the improvement was not considered clinically significant. Because effectiveness was not proven, the benefits of Xiidra did not outweigh its risks."

Novartis did not immediately detail future plans for Xiidra or say if it would resubmit the application after seeking more data when Reuters contacted it on Saturday.

(Reporting by John Miller; Editing by Himani Sarkar)