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.
