Avrobio Inc. said its experimental gene therapy for a form of Gaucher disease was given orphan-drug status by the U.S. Food and Drug Administration.

Gaucher disease is a rare genetic disorder that affects the spleen and liver, among other organs. The Cambridge, Mass.-based company will be investigating its treatment AVR-RD-02 for type I Gaucher disease, which is the most common form of the lysosomal storage disorder. Patients with the form known as type II rarely live past the age of three.

Patients with type I Gaucher disease, who are predominantly of Ashkenazi Jewish heritage, experience symptoms such as anemia, low platelet count, fatigue and easy bleeding that is difficult to stop. Patients with the disease are deficient in the enzyme glucocerebrosidase, and the gene therapy treatment would potentially modify the patients' stem cells so that they express the enzyme.

The existing standard of care involves regular transfusions to replace the missing enzyme, with patients experiencing musculoskeletal pain and fatigue, Avrobio said in an Oct. 24 news release.

The biotechnology company is recruiting patients in Canada to begin a phase 1/2 study of the treatment.

The FDA grants orphan-drug status to a therapy that treats a rare disease or condition. The special status provides seven years of marketing exclusivity, plus six months if approved for use in children in addition to other incentives.