I was on the Sutent for one round at 50mg and one at 25 mg, the side effects were so horrible that I could not continue. Terrible mouth sores and barely able to walk. Since I have a subtype that responds to Chemo I have found beeen doing much better . Ask your Dr. if there is a chance that your Dad s type could respond to something else. Although Sutent does work ,sometimes the side effects are worse than the disease.