The present invention provides active metablites of 3-(4-(7H-pyrrolo[2,3-d] pyrimidin-4-y1)-1H-pyrazol-1-y1)-3-cyclopentylpropanenitrile that modulate the activity of Janus kinases and are useful in the treatment of diseases related to activity of Janus kinases including, for example, immune-related diseases, skin disorders, myeloid proliferative disorders, cancer, and other diseases.本發明係有關一種3-(4-(7H-吡咯并[2,3-d]嘧啶-4-基)-1H-吡唑-1-基)-3-環戊基丙烷腈之活性代謝物,其調節傑納斯激酶(Janus kinase)之活性且用於治療與傑納斯激酶活性有關之疾病,該等疾病包括(例如)免疫相關疾病、皮膚病症、骨髓增殖性病症、癌症及其他疾病。