Primary objective:~To evaluate the clinical and laboratory safety of SB-509 when given as a single treatment by an intramuscular injection. To determine the maximum tolerated dose (MTD) of a single treatment by intramuscular injection by SB-509.~Secondary objective:~To evaluate the lower extremity clinical effects of SB-509 treatment on lower limb diabetic neuropathy by symptoms, neurological examination, and lower extremity electrophysiological testing.
The purpose of this study is to evaluate the clinical and laboratory safety of SB-509 when given as a single treatment by an intramuscular injection to subjects with diabetic neuropathy.