The present invention relates to aminopeptidase N (APN) inhibitor conjugates of formula I wherein W is a -CO- or an -SO- group and at least one of R or R represents (OCH- CH)n-X, where n is an integer of 1 to 100 and X represents H or a detectable label or a therapeutic, and the other represents an alkoxy group or OH, and wherein R Rand R is independently selected from an alkoxy group or (OCH-CH)n-X, where n is an integer of 1 to 100 and X represents H or a detectable label or a therapeutic, and Ris selected from the group comprising: wherein R is an alkyl group. Furthermore, the present invention relates to a diagnostic and/or pharmaceutical composition comprising the conjugate of the invention. The present invention also relates to the conjugate or composition of the invention for use in the diagnosis or treatment of APN-associated diseases like for example angiogenesis in cancer, rheumatoid arthritis, leukemia and diabetic nephropathy, as well as to the use of the conjugate or of the composition of the invention in the diagnosis or treatment of angiogenesis in cancer, rheumatoid arthritis, leukemia and diabetic nephropathy. In a further aspect, the present invention relates to kits comprising the conjugate or composition of the invention. The conjugate or pharmaceutical/diagnostic composition of the invention can also be used in or imaging studies of aminopeptidase N.
