Topical Sodium Nitrite in Sickle Cell Disease and Leg Ulcers

The investigators are conducting a Phase II prospective and placebo controlled study of a topical cream containing sodium nitrite compared to the current standard of care. Sodium nitrite is a local donor of nitric oxide, which is known to improve blood flow and decrease bacterial load in the ulcer bed. The primary objectives are to evaluate the safety of topical sodium nitrite cream treatment in patients with sickle cell disease and chronic leg ulcers and to determine its effectiveness in accelerating the healing process and decreasing the pain associated with ulceration.

Potential benefit will be a durable resolution or improvement of the leg ulcer and its associated pain. Possible side effects include decreased blood pressure and methemoglobinemia, secondary to sodium nitrite absorption through the ulcerated skin.

Funding source FDA OOPD.

Chronic leg ulcers are a complication of many blood disorders such as sickle cell disease, thalassemia, and other red blood cell disorders. In these disorders, red blood cells break down earlier than normal, which researchers suspect may cause or contribute to the development of leg ulcers; however, the exact cause is unknown, and current therapies are not very effective. Researchers are interested in determining if a research cream made with sodium nitrite, a substance that is known to increase blood flow by dilating blood vessels, may speed up the healing of skin ulcers.

Investigators are planning to enroll fifty patients with sickle cell disease to be randomized and treated twice a week with sodium nitrite cream or a placebo for ten weeks. The following events will be compared in treatment and placebo arms: a) changes in blood pressure; b) changes in pulse oximetry; c) changes in methemoglobin levels; d) any adverse events; e) rate of SCD related complications; f) changes in biomarkers of inflammation and other laboratory data such as complete blood count and chemistries.

In order to determine if topical sodium nitrite accelerates wound healing and decreases pain at the wound site compared to placebo in patients receiving similar levels of wound care, investigators will a) accurately measure and photograph ulcers at baseline, after a two week run-in period and at predefined time points during the study and compare treatment arm to placebo; b) pain scores at wound sites will be recorded and compared for the two groups, c) Investigators will calculate opioid intake in the two arms and d) quality of life measures before and at the end of the trial

Eligibility Criteria:
Inclusion Criteria:

* Subjects must have a diagnosis of sickle cell disease (SS, SC, Sß-thalassemia, SD, SOArab).
* Have one or more ulcers of the one or both leg or foot.
* Total surface area of leg ulcer(s) that will receive treatment must be no larger than 100 cm2.
* No history of congenital methemoglobinemia.
* Have documented normal G6PD activity.

Exclusion Criteria:

* Exposure to therapeutic nitric oxide, L-arginine, nitroprusside or nitroglycerine within the past 1 week.
* Subjects presenting with clinically diagnosed bacterial infection (e.g., osteomyelitis, pneumonia, sepsis or meningitis).
* Subjects who have a pre-existing methemoglobinemia (more than 3.5% on two different occasions).
* Patients who are currently enrolled in any other investigational drug study (this does not include observational or natural history protocols).
* Use of PDE5 inhibitors, such as sildenafil, 4 days prior to screening.
* Pregnant women (urine or serum HCG +) or nursing mothers.
* The following list of drugs and agents may cause methemoglobinemia and should be avoided while on this study:

Anesthetics (local): Benzocaine, procaine, prilocaine, Anbesol, Orajel Antimalarials: chloroquine, primaquine, quinacrine Aniline dyes Chlorates Dapsone Diarylsulfonylureas Doxorubicin Metoclopramide Nitric and nitrous oxide Nitrobenzenes (shoe and floor polish and in paint solvents) Nitroethane (artificial nail remover, propellant, fuel additive) Nitrofurantoin (furadantin) Pyridium (phenazopyridine) Phenacetin Phenylhydrazine Rasburicase Sulfonamides (sulfacetamide, sulfamethoxazole, sulfanilamide, sulfapyridine)