596556 The disclosure relates to melanocortin receptor-specific (MC4-R specific) cyclic peptides of Formula (I) or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4a, R4b, R4C, R5, x and y are as defined in the specification. These compounds are particularly useful in the treatments of energy homeostasis and metabolism related (e.g. diabetes), food intake related and/or energy balance and body weight related diseases, disorders and/or conditions, including obesity, overweight and diseases, disorders and/or conditions associated with obesity and/or overweight, such as type 2 diabetes and metabolic syndrome. Compounds of the disclosure include: Ac-Arg-cyclo(Glu-Asn-D-Phe(4-CN)-Arg-Trp-Orn)-NH2 (SEQ ID NO:48)； Ac-Arg-cyclo(Glu-Gln-D-Phe(4-CN)-Arg-Trp-Orn)-NH2 (SEQ ID NO:51)； Ac-Arg-cyclo(Glu-Asn-D-Phe(4-F)-Arg-Trp-Orn)-NH2 (SEQ ID NO:74)； Ac-Arg-cyclo(Glu-Asn-D-Phe(4-CN)-Arg-Trp-Orn)-OH (SEQ ID NO:90)； Ac-Arg-cyclo(Glu-Gln-D-Phe(4-CN)-Arg-Trp-Orn)-OH (SEQ ID NO:91)； Ac-Arg-cyclo(Glu-Gln-D-Phe(4-F)-Arg-Trp-Orn)-NH2 (SEQ ID NO:97)； Ac-Arg-cyclo(Glu-Pro-D-Phe(4-CN)-Arg-Trp-Orn)-NH2 (SEQ ID NO:44)； Ac-Arg-cyclo(Glu-Pro-D-Phe(4-F)-Arg-Trp-Orn)-NH2 (SEQ ID NO:72)； and Ac-Arg-cyclo(Glu-Pro-D-Phe(4-F)-Arg-Trp-Orn)-OH (SEQ ID NO: 107).
