Evidence exists to suggest that aging of the kidney may contribute to the onset and progression of chronic kidney disease (CKD). Rapamycin is a drug that is a potential modulator of the aging process and additionally may decrease the formation of fibrosis (scarring) in the kidney. A feline formulation of the drug is available and the purpose of this study is to assess the potential benefit of the drug in cats with CKD. Your cat will receive complimentary assessment and management of disease by a board-certified specialist in feline CKD as well as standard of care laboratory monitoring regardless of study group. Cats randomized to the study drug group will possibility benefit from this therapy. There is no cost to you for enrolling your cat in this study. You will receive complimentary physical examination for your cat and diagnostic testing. You will also receive $25 per visit incentive.