The present invention provides a compound of formula I； or a pharmaceutically acceptable salt thereof, wherein X is defined herein. The invention also relates to a method for manufacturing the compounds of the invention, and its therapeutic uses. The present invention further provides pharmaceutical composition of the compounds of the invention and a combination of pharmacologically active agents and a compound of the invention.本發明提供式I化合物或其醫藥上可接受之鹽，其中X係如本文所定義。本發明亦係關於製造本發明化合物之方法及其治療用途。本發明進一步提供本發明化合物之醫藥組合物及藥理學活性劑與本發明化合物之組合。
