Patient recruitment is complete.
One study will determine whether the drug will prevent the progression of nonproliferative diabetic retinopathy to proliferative diabetic retinopathy which would require laser treatments. The other study will determine whether this drug will prevent minimum swelling from diabetic retinopathy from becoming significant and requiring laser treatment. The study will also determine how well the drug is tolerated in different dosages and whether the drug affects sexual functioning in men. There is no cure for this type of cancer once it spreads outside the eye. Investigators are studying a new treatment to reduce tissue loss and help prevent the spread of cancer.