Key Inclusion Criteria:  Is in good general health as determined by Investigator's review. Has a body mass index (BMI) between 18 and 35 kg/m2. Non- or ex-smoker (> 1 year) and has not used any nicotine containing products within 12 months prior to screening. For females, is not currently pregnant and is either of non-childbearing potential or willing to use an adequate method of birth control. For males, must agree to use barrier contraception and not to donate sperm  Key Exclusion Criteria:  Is pregnant, lactating, or planning a pregnancy during the study. Tests positive for COVID-19 after screening is complete and subject is confirmed to enroll History of or active cardiac disease, including congestive heart failure, angina, or any arrhythmia. Has any history or currently active type of cancer except excised or cured basal cell carcinoma. Has an immunological disorder such as, but not limited to, human immunodeficiency virus (HIV), acquired, or congenital immune deficiency syndrome; autoimmune diseases, such as, but not limited to, rheumatoid arthritis, systemic lupus erythematosus, seronegative spondyloarthropathies or vasculitis, or any infection. Positive urine screen for alcohol, cotinine, THC and/or drugs of abuse Has positive screening test for hepatitis B virus (HBV) or hepatitis C virus (HCV).  Key Inclusion Criteria- PDN Cohort  A diagnosis/history of Type 2 diabetes mellitus The pain is present in both feet/legs with symmetrical onset The pain is characterized as burning, painful, cold or electrical shocks in nature The pain is associated with tingling, numbness, itching or pins and needles type sensations The pain has been present and consistent for ≥ 6 months  Key Exclusion Criteria- PDN Cohort  Diagnosis of Type 1 diabetes Has serious or unstable cardiovascular, hepatic, renal, respiratory or hematological illness Has a history or currently active type of cancer except excised or cured basal cell carcinoma. Has a History of psychological conditions or neurological disorders Has a History of lower back pain with radiculopathy Has received non-pharmacological treatment for pain within 14 days Has a history of frequent and/or severe allergic reactions with multiple medications