A new treatment called canaloplasty, for primary open angle glaucoma (POAG), a disease that's the second-leading cause of blindness, is quickly gaining acceptance. Tiny catheters are inserted into small drainage structures within the eye, enabling surgeons to enlarge the compromised outflow passages, ultimately relieving the pressure.
The FDA has just granted expanded indication for microcatheters made by iScience Interventional (Menlo Park, California) that surgeons can use in treating millions of patients with POAG.
"There is no such thing as a gold standard treatment' for POAG," Bradford Shingleton, MD, of Ophthalmic Consultants of Boston and associate clinical professor of ophthalmology at Harvard Medical School (Boston), told Medical Device Daily. "Most people are controlled with medications. Unfortunately, not everyone is controlled by those modalities and when surgery is indicated, there are a host of procedures. The advantage of our current technique is that we can design a procedure specifically for individuals."
Canaloplasty lowers intraocular pressure (IOP) with few surgical complications using a non-penetrating approach to restore more natural aqueous outflow pathways. Shingleton published results of a study earlier this year (Journal of Cataract & Refractive Surgery, March 2008) that indicates that the procedure, in combination with phacoemulsification and IOL implantation, effectively lowers IOP with few complications and with continued control of IOP in patients followed up to 12 months.
iScience's microcatheters were used in that study, which included 54 eyes.
Glaucoma affects an estimated 65 million people worldwide. About 120,000 Americans are blind due to glaucoma, according to the Glaucoma Research Foundation (San Francisco). The disease is caused when the natural fluid channels (Schlemm's canal) in the eye become blocked or clogged. This causes fluid to build up. When this occurs, IOP increases, causing permanent damage to the optic nerve. There is no cure for glaucoma, but its progression can be halted or slowed by lowering the IOP.
Ron Yamamoto, iScience's chief scientific officer and director, likens the new therapy to interventional work in other fields such as cardiology. Members of the management team at iScience "come from interventional radiology and cardiology. Mother Nature is the best bioengineer, so we're always interested in restorative medicine."
iScience already was making the microcatheters, which are about the size of four to five human hairs combined, when it discovered that some surgeons were starting to use them for the new canaloplasty procedure. The company then pursued the specific indication from the FDA via a 510(k) application.
Now, like interventional cardiology and neuroradiology, canaloplasty is emerging as an alternative to more-invasive surgical procedures such as trabeculectomy, during which a piece of tissue in the drainage angle of the eye is removed, creating an opening. That opening is covered with a tissue flap from the sclera (the white part of the eye) and the conjunctiva (the clear thin covering over the sclera).
The opening then allows fluid to drain. The tissue over the opening rises to form a blister, called a bleb. After surgery, the surgeon will periodically check the bleb to make fluid is still draining. Unfortunately, this type of surgery doesn't always work or needs to be redone. A host of other complications are possible, making the simpler canaloplasty — which has been performed for about three years — much more appealing.
"It turns out that canaloplasty is attractive because it does have good effects in lowering pressure and avoiding bleb development," Shingleton said. "It's safer and more comfortable for patients."
"We have been using the same surgical procedures for the last 50 years with only small modifications," said Richard Lewis, MD, past-president of the American Glaucoma Society (San Francisco). "Canaloplasty strengthens the ophthalmologists' options for patients with POAG. Ophthalmologists have recognized for decades that the ideal solution to glaucoma would restore or maintain the eye's natural drainage system. The canaloplasty does just that."
iScience is working on establishing reimbursement for the single-use microcatheters, which cost $795, Ernie Edwards, VP of marketing, reimbursement and customer care, told MDD. "We filed a submission with the American Medical Association for Category 3 code in 2006. CMS gave us facility fee coverage ... we're about 60% of the way through the reimbursement process."
iScience, which was founded in 1999 and is ventured-backed, is sufficiently funded to commercialize the microcatheters independently, Edwards said.
The company reported in 2005 that it closed a $15 million Series C financing. New investor Three Arch Partners led the round, with existing investors Prism Venture Partners, De Novo Ventures, Asset Management Partners and Pacific Horizon Ventures also contributing (MDD, April 1, 2005).