This invention relates to a compound with EP4 antagonistic activity, or a pharmaceutically acceptable salt with EP4 receptor antagonistic activities, which is useful in the treatment of cartilage disease. This invention also relates to a compound of formula (I), (II), (III), (IV), (Va) or (Vb), or a pharmaceutically acceptable salt thereof with EP4 receptor antagonistic activities, which is useful in the treatment of cartilage disease. This invention also relates to a pharmaceutical composition for the treatment of cartilage disease which comprises a therapeutically effective amount of a compound of formula (I), (II), (III), (IV), (Va) or (Vb), or a pharmaceutically acceptable salt thereof. Further this invention relates to a method for the treatment of cartilage disease in an animal subject including a mammalian subject, which comprises administering to the animal subject including a mammalian subject a compound of the formula (I), (II), (III), (IV), (Va) or (Vb), or a pharmaceutically acceptable salt thereof.
