Ranibizumab for Neovascularization in Sickle Cell Retinopathy

In the U.S., about 10% of African Americans have an abnormal hemoglobin gene. About 8% of
African Americans are heterozygous for Hemoglobin S. In the United States, sickle cell
anemia primarily occurs in the black population, with approximately 0.2% of African American
children afflicted by this disease. It may be associated with other hemoglobinopathies as
well. The prevalence in adults is lower because of the decrease in life expectancy.
Systemically, the sickle cell anemia variation (SS) produces the most symptoms. With
respect to the eye, the sickle cell disease mutation (SC) produces the most effects.
Overall, the sickle cell trait expression (AS) produces the fewest complications.

- Among patients with SC or SThal, the incidence of proliferation sickle cell retinopathy
is 33% and 14% respectively.

- Proliferative sickle cell retinopathy is the major cause of vision loss in sickle cell
disease.

For sickle cell retinopathy, the commonly used therapeutic modalities include laser retinal
photocoagulation, retinal cryotherapy, and vitrectomy/membranectomy depending on the
severity of the disease. The most effective therapeutic modality with minimal postoperative
complications appears to be scatter laser retinal photocoagulation.

A single case study of bevacizumab was found to effective in short term regression of
neovascularization and improving vision after a single injection. Further study with
ranibizumab is warranted.

Recent clinical trials (Marina and Anchor) have demonstrated that ranibizumab is effective
in treating patients with CNV with age-related macular degeneration. Retinopathy in sickle
cell disease has also been linked to VEGF. Therefore, patients with sickle cell retinopathy
should respond to ranibizumab therapy.

This is an open-label single dose, phase I study of intravitreally administered ranibizumab
in patients with sickle cell retinopathy.

Consented, enrolled subjects will receive a single open-label intravitreal injection of 0.5
mg ranibizumab.

Three subjects from one site in the United States will be enrolled.

Patients will receive one dose of 0.5 mg ranibizumab administered intravitreally.

Inclusion Criteria:

- Patients with sickle cell anemia and retinopathy

- Over age 18 years

- Non-pregnant

Exclusion Criteria:

- Pregnant

- Glaucoma

- Patients using anticoagulants (e.g., warfarin)

- Retinal detachment