The disclosure provides methods of treating gout in patients comprising administering a PEGylated uricase. Also provided are methods of treating gout in patients comprising co-administering a PEGylated uricase and azathioprine immunosuppressive therapy. Also provided are methods of reducing intolerance or enhancing immuno-tolerance to a PEGylated uricase and prolonging the urate lowering effect comprising co-administration of the PEGylated uricase and azathioprine immunosuppressive therapy.