The present invention relates to substituted fused tricyclic compounds of formula (I) or (Ia), their tautomers, polymorphs, stereoisomers, prodrugs, solvates, co-crystals, pharmaceutically acceptable salts, pharmaceutical compositions containing them and methods of treating conditions and diseases that are mediated by JAK activity. The compounds of the present invention are useful in the treatment, prevention or suppression of diseases and disorders mediated by JAK activity. Such conditions include, but not limited to, arthritis, Alzheimer's disease, autoimmune thyroid disorders, cancer, diabetes, leukemia, T-cell prolymphocytic leukemia, lymphoma, myleoproliferation disorders, lupus, multiple myeloma, multiple sclerosis, osteoarthritis, sepsis, psoriatic arthritis, prostate cancer, T-cell autoimmune disease, inflammatory diseases, chronic and acute allograft transplant rejection, bone marrow transplant, stroke, asthma, chronic obstructive pulmonary disease, allergy, bronchitis, viral diseases, or Type I diabetes, complications from diabetes, rheumatoid arthritis, asthma, Crohn's disease, dry eye, uveitis, inflammatory bowel disease, organ transplant rejection, psoriasis and ulcerative colitis. The present disclosure also relates to process for the preparation of such compounds, and to pharmaceutical compositions containing them.La présente invention concerne des composés tricycliques substitués représentés par la formule (I) ou (Ia), leurs tautomères, des polymorphes, des stéréoisomères, des promédicaments, des solvates, des co-cristaux, des sels pharmaceutiquement acceptables, des compositions pharmaceutiquement acceptables les contenant et des méthodes permettant de traiter des affections et des maladies provoquées par l'activité de JAK. Les composés de la présente invention sont utiles dans le traitement, la prévention ou la suppression de maladies et de troubles provoqués par l'activité de JAK. De telles affections comprennent, entre autres, l'arthrite, la mala
