Hemispherx Biopharma Inc. said Tuesday that it has received approval of a new drug application in Argentina for its treatment for chronic fatigue syndrome.

The Philadelphia-based biotechnology company said rintatolimod, which has the U.S. trade name Ampligen, will be marketed by GP Pharm, Hemispherx's commercial partner in Latin America.

"We believe that rintatolimod is the first drug to receive approval for this indication anywhere in the world," Hemispherx said in a statement. "We also believe that there are no other products in the pipeline for approval, worldwide, for this debilitating disease."

The companies said they will continue to seek approval of rintatolimod in additional Latin American countries.