Barely a year after the U.S. FDA shackled Abeona Therapeutics Inc.’s cell-based gene therapy with a complete response letter, the agency has approved it for treating a rare and genetic skin disease. Zevaskyn (prademagene zamikeracel), for treating wounds in adult and pediatric patients with recessive dystrophic epidermolysis bullosa, will be priced in the U.S. at $3.1 million.