Rheopheresis - an investigational treatment for Dry Macular Degeneration.
 Background:
Rheopheresis treatment is based upon a hypothesis that macular degeneration is a disease of vascular origin.
Bruch's membrane is a basement membrane located
between the retinal pigment epithelium and the
choroid. Bruch's membrane represents a barrier to diffusion of nutrition
from the vessels of the choroid to the retinal pigment
epithelium. Large molecules, if trapped in
Bruch's membrane, would interfere with the flow of
smaller, necessary molecules required for the health of
retina. Rheopheresis treatment alters blood flow characteristics, and as a result tissue
perfusion, by altering the composition of the blood.
The elimination of high-molecular weight plasma
proteins, including fibrinogen, a2-macroglobulin,
LDL-cholesterol, fibronectin, von-Willebrand-factor and vitronectin, results in the
reduction of blood viscosity and improves red blood cell (RBC) flexibility. As a result blood is able to flow more easily through the choroidal blood vessels. The improved choroidal microcirculation more effectively supplies the retinal cells with oxygen and nutrients needed for proper function.
THE MIRA-1 TRIAL (Multicenter Investigation of
Rheopheresis for AMD)
MIRA-1 is a phase III FDA pivotal trial designed to evaluate the safety and efficacy of the RHEO™ Procedure in patients with intermediate-to-late stage Dry Macular Degeneration (AMD). MIRA-1 completed enrollment of 185 patients in December 2004. Final data submission for FDA evaluation is expected later in the year. The filtration device for RHEO treatments has not as of yet been approved by FDA for commercial use in the USA.
Patients received
eight Rheopheresis treatments over a 10-week treatment period. The duration of each treatment session was 2 to 4 hours. Treatments can be given as in-office procedure or in dialysis/blood centers. No sedation is
required.
Ophthalmologists determined ophthalmic
eligibility criteria and supervised efficacy assessments.
Nephrologists performed enrollment physicals,
determined medical eligibility criteria and supervised treatments.
Rheopheresis is not typically performed
by a physician. In MIRA-1 study, medical technicians
or nurses provided all 343 treatments. Physician supervision was indirect.
Rheopheresis patients require insertion of
16-, or 18-gauge needles into veins of both forearms.
The patient's blood circulates from one arm, through the dual-filter filtration system, and back to the body through the other arm. Establishing and maintaining competent antecubital (forearm)
venous access over a 2- to 4-hour procedure
in elderly patients remains the most frequently
encountered technical challenge.
In this process, no more than 600 mL blood (i.e. 10 to 12% of the patient's total blood volume) is circulating within the RHEO system at any one time.
At 12 months RHEO-treated eyes had 1.6 lines of better vision than non-RHEO treated eyes. At 12 months only 4.0% of
the RHEO-treated eyes had lost vision more than 3-lines. In contrast, 18.2% of the eyes in the non-RHEO treated
eyes lost more than 3-lines of vision.
Treatment related adverse event was reported in 2.2% patients.
Current RHEO Clinical Studies
PERC (Prospective Evaluation of Rheopheresis in Canada).
LEARN-1 (Long-term Efficacy in AMD from Rheopheresis in North America)
LEARN-2 (Long-term Efficacy in AMD from Rheopheresis in North America).
Enrollment in Learn-2 is scheduled to begin June 2005.
Contact Information:
RHEO website
PHONE: 1-877-AMD-EYES (1-877-263-3937)
EMAIL: info@rheo.com
REFERENCES: Trans Am Ophthalmol Soc. 2002;100:85-106; J Clin Apheresis. 2005 May 12.
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