Onvitrelin ucalontide ([Phor18-LHRH (338613)]) is an analogue of luteinizing hormone releasing hormone (LHRH) with antineoplastic activity. Onvitrelin ucalontide is a peptide with sequences of KFAKFAKKFAKFAKKFAKQHWSYGLRPG. Onvitrelin ucalontide effectively inhibits breast cancer , ovarian cancer and prostate cancer xenografts in mouse model.