The goal of this Small Business Innovation Research Phase I project is to develop a next generation glaucoma drainage implant, called the MIDI-Ray . The MIDI-Ray name is derived from the Miami-InnFocus-Drainage- Implant ( MIDI ); the Ray comes from the fact that it resembles a Manta-Ray. The first generation device, called the MIDI-Tube , was developed by InnFocus LLC, and the Bascom Palmer Eye Institute. Its unique features include; 1) a micro tube designed using the Hagen-Poiseuille pressure flow principle that limits flow and thereby prevents hypotony, 2) a novel biomaterial called poly(styrene-block-isobutylene-block-styrene) ( SIBS ) that does not form clinically significant scar tissue in the eye and 3) a combination of features 1 and 2 which provides a very atraumatic device that does not demonstrate erosion or migration and that demonstrates 100% patency at one year in the rabbit model. This first generation device demonstrated practicality in a limited clinical study; however, it was not as effective in very severe glaucoma patients without the use of the anti-metabolite drug Mitomycin-C (MMC). The use of anti-metabolites in glaucoma patients is still controversial as the long-term effects of these drugs vary depending upon dosage, method of application, method of rinsing out, site of application and health of the conjunctiva/Tenons and sclera. The MIDI-Ray is similar to the MIDI- Tube but incorporates a thin microplate at the distal end of the tube to prevent the subconjunctival/Tenon flap from healing closed. The goal of this grant is to determine if this new MIDI-Ray design will function in the rabbit eye with and without the use of a drug. The drug to be tested will be the antiproliferative drug paclitaxel, which is milder than MMC and does not kill cells, rather it renders them sterile. The drug will be released in a controlled manner from the MIDI-Ray microplate to eliminate variances experienced with the delivery of conventional anti-metabolite drugs that are introduced in a non-controlled manner at the time of implantation. Drainage devices may be the most effective and last resort treatment; however, they suffer from many problems. For example, currently marketed designs are made of silicone rubber and polyethylene or polypropylene which creates extensive fibrosis within the eye which can lead to reduced filtration. In addition, the plates (with their capsules) and tubes are rather large with concomitant risk of diplopia and hypotony; which often require secondary interventions such as suturelysis. The MIDI-Ray is made from an extremely soft SIBS material with a controlled filtration rate that should prevent erosion, scar tissue formation and hypotony. If it functions as anticipated, it will be effective in a wide range of patients and will be relatively simple to implant due to its small size. The biocompatible SIBS material will minimize encapsulation in the eye and the release of paclitaxel from the device will prevent the bleb from fibrosing. This is the same concept as the paclitaxel- coated coronary stent commercialized by Boston Scientific Corporation, called the TAXUS. stent (PI is the inventor), which prevents re-stenosis in the coronary arteries by limiting smooth muscle proliferation. It is expected that this simple device will provide a better option to both the glaucoma and anterior segment surgeons to effectively treat their patients in a consistent, controlled manner; hopefully at an earlier stage before visual acuity is affected. It is anticipated that Phase I testing of the device will demonstrate chemical and biological viability. Phase II will be geared toward optimization, long-term in vivo testing of the device, GLP pre-clinical testing, regulatory submissions and stepping up production for commercialization. OUBLIC
This project is sought develop an easy to implant glaucoma drainage device to treat a growing problem with the aging population which is presently the second most common cause of blindness in the U.S. This preventable blindness is treatable to some degree through aggressive drug therapy, filtering surgery and/or use of aqueous shunt implants; however, the long-term outcomes with the current products are less than desirable. The MIDI-Ray is a novel glaucoma drainage device comprised of a new biostable polymeric material that is extremely biocompatible in the eye, and has shown insignificant encapsulation as compared to silicone rubber and when combined if necessary, with an antiproliferative drug, paclitaxel, and is controllably released from it, should prevent the progression of the disease. ? ? ?
