Dec 21 (Reuters) - Clene said on Thursday that the U.S. Food and Drug Administration (FDA) found data from the company's mid-stage study for the treatment of a type of neurodegenerative disease to be insufficient to support accelerated approval.

Shares of the company fell 20% in premarket trading.

The FDA determined that the initial findings on biomarker NfL reduction from the mid-stage studies were insufficient.

Nfl or Neurofilament protein is a marker of nerve cell degeneration. Higher levels of the protein are considered a predictor of a more rapid decline in clinical function and a greater risk of death in patients.

The company said that it is looking to provide supplemental data for further engagement with the FDA in the first half of 2024.

(Reporting by Christy Santhosh; Editing by Shweta Agarwal)