Shares of the Australia-based drug developer Mesoblast (ASX:MESO) saw a decline of 66.4% to $1.34 in premarket trading following the US Food and Drug Administration’s (FDA) denial of the firm’s main proposal of cell therapy - remestemcel-L.

This investigational therapy was aimed at treating children under 12 years of age who faced complications post stem cell or bone marrow transplants.

Mesoblast was looking for approval for this experimental therapy over two years since the FDA rejected it the first time.

Mesoblast noted that the FDA demanded further data to back marketing approval.

As of the last close, Mesoblast’s U.S.

listed shares had risen by 37.11% this year.

Mesoblast is a biopharmaceutical company that specializes in developing innovative cellular medicines.