Squalamine for the Treatment in Proliferative Diabetic Retinopathy

Inclusion Criteria: * Age \>= 18 years * Individuals \<18 years old are not being included because PDR is so rare in this age group that the diagnosis of PDR may be questionable. * Diagnosis of diabetes mellitus (type 1 or type 2) * Any one of the following will be considered to be sufficient evidence that diabetes is present: * Current regular use of insulin for the treatment of diabetes * Current regular use of oral anti-hyperglycemia agents for the treatment of diabetes * Documented diabetes by ADA and/or WHO criteria (see Procedures Manual for definitions) * At least one eye meets the study eye criteria * Able and willing provide informed consent Exclusion Criteria: * Significant renal disease, defined as a history of chronic renal failure requiring dialysis or kidney transplant. * A condition that, in the opinion of the investigator, would preclude participation in the study (e.g., unstable medical status including blood pressure, cardiovascular disease, and glycemic control). * Individuals in poor glycemic control who, within the last 4 months, initiated intensive insulin treatment (a pump or multiple daily injections) or plan to do so in the next 4 months should not be enrolled. * Participation in an investigational trial within 30 days of randomization that involved treatment with any drug that has not received regulatory approval for the indication being studied. * Note: study participants cannot receive another investigational drug while participating in the study. * Known allergy to any component of the study drug. * Blood pressure \> 180/110 (systolic above 180 or diastolic above 110). * If blood pressure is brought below 180/110 by anti-hypertensive treatment, individual can become eligible. * Myocardial infarction, other acute cardiac event requiring hospitalization, stroke, transient ischemic attack, or treatment for acute congestive heart failure within 4 months prior to randomization. * Systemic anti-VEGF or pro-VEGF treatment within 4 months prior to randomization. * These drugs should not be used during the study. * For women of child-bearing potential: pregnant or lactating or intending to become pregnant within the next 3 years. * Women who are potential study participants should be questioned about the potential for pregnancy. Investigator judgment is used to determine when a pregnancy test is needed. * Individual is expecting to move out of the area of the clinical center during the study. * History of allergy to Squalamine