Mesoblast (ASX:MSB) received seven years of orphan-drug exclusive approval from the US Food and Drug Administration for Ryoncil for the treatment of steroid-refractory acute graft versus host disease in pediatric patients aged two months and older, according to a Wednesday Australian bourse filing.

The period of statutory exclusivity means that the regulator will not approve another mesenchymal stromal or stem cell product for this indication for seven years from the approval of Ryoncil, the filing said.

Separately, Mesoblast has biologic exclusivity preventing another sponsor from referencing the Ryoncil biologic license application until December 2036.

Mesoblast's shares fell past 1% in recent trading on Thursday.