To provide a pharmaceutical combination therapy for the treatment or prevention of arthritis, such as human rheumatoid arthritis.

The pharmaceutical combination therapy comprises co-administrating a Janus Kinase inhibitor or a pharmaceutically acceptable salt thereof and at least one anti-arthritic agent or a pharmaceutically acceptable salt thereof. The Janus Kinase inhibitor is preferably a 7H-pyrrolo[2,3-d]pyrimidine derivative and, concretely, 3-{(3R, 4R)-4-methyl-3-[methyl-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)-amino]-piperidin-1-yl}-3-oxo-propionitrile or a pharmaceutically acceptable salt thereof is illustrated as a preferable compound.