About a year after the U.S. FDA cleared Krystal Biotech Inc.’s topical gene therapy, Vyjuvek (beremagene geperpavec), as the first drug for recessive or dominant dystrophic epidermolysis bullosa, competitor Abeona Therapeutics Inc. disclosed a complete response letter (CRL) from the FDA related to its cell-based graft therapy, prademagene zamikeracel.