Title: A novel biocompatible implant for glaucoma surgery: The BioChannel device.
Funder: Department of Health and Social Care

Abstract: The BioChannel will maintain an intraocular pressure (IOP) of 10-12 mm Hg with minimal 24-hour variation. The device is designed to address the limitations of currently used glaucoma drainage devices (GDDs) (Appendix page-2). The BioChannel comprises a tube to drain fluid from the anterior chamber into a spacer flap that mimics the trabecular meshwork to allow aqueous flow to seep into the subconjunctival space. Key innovations include: (1) The spacer flap is fabricated from a phosphorylcholine (PC) polymer. PC polymers have been shown since the early 1990s to have an excellent clinical record with several registered products including contact lens and coronary stents. PC polymers are clinically proven to be resistant to protein absorption. This results in reduced cell adhesion and activation to suppress capsule formation and fibrosis. Any capsule formation that might occur over time with the BioChannel spacer is anticipated to be much easier to remove than is possible with any of the currently used GDDs. PC materials are also resistant to bacterial adhesion and biofilm formation. (2) Pressure control is achieved by the tube from the anterior chamber draining into the PC hydrogel spacer. Pressure control will be optimised by correlating spacer dimensions, internal placement of the tube and hydrogel properties with different aqueous flow properties. The hydrogel structure of the spacer mimics the network structure of the trabecular meshwork to allow outflow over the entire surface of the spacer. (3) Implantation of the BioChannel will be accomplished in an approximately 10 minute period by insertion into the subconjunctival space in a manner analogous to that of an intraocular lens inserted during cataract surgery. The PC polymer can be compacted without sticking to itself. This enables a new insert technique for tube placement (30 seconds) which is much more accurate and rapid compared to current GDD placement methods which require several minutes and considerable surgical skill (Appendix page-2). The project comprises of three work packages (WPs) with clearly defined milestones. A detailed Gantt chart is attached. WP1 is designed to establish the documentation needed for eventual clinical trials, regulatory approvals and introduction to the NHS. Discussions will be initiated with appropriate device manufacturers to complete contract negotiations by the end WP1 to manufacture the BioChannel. Technical efforts will include continued prototyping which has already been initiated to optimise BioChannel outflow and pressure maintenance properties. Device fabrication, sterilisation and physicochemical characterisation will also be conducted to provide the necessary datasets required for technology transfer for manufacturing and for the documentation required for regulatory approvals (Technical File). An externally funded PoC study will be conducted. This in vivo testing framework provides considerable lift to our proposal since the contributing costs are >10% of the total application. WP2 is designed to scale up device manufacture with a 3rd party company and to complete preclinical development. Demonstration batches will be bench tested to ensure functional and material properties are met; GMP documentation prepared; GMP qualified analytical methods developed and validated; GMP batches tested pre & post sterilization using quality tests identified by the Target Product Profile (TPP); Stability studies to support product & clinical trial (accelerated & long term); Pre-clinical GLP biocompatibility studies meeting ISO 10993 (externally funded) including at 12 week implant study anticipated in pigs. WP3 will include completion of the Clinical Utility Review, Design Dossier & Technical File, GP letter, consent forms and Patient Information Sheets (PIS), IRAS forms, and Clinical Engineering and Notified Body preliminary reviews. All necessary documentation will be submitted to appropriate ethical committees to achieve approval ( no-objection letter ) for a clinical efficacy study.

Lay abstract: Glaucoma is the most common cause of irreversible blindness in the world, affecting more than 70 million people, of whom 7 million are blind. The only proven treatment for glaucoma is lowering the pressure in the eyeball. Clinical trials around the world show that if the pressure can be maintained at low levels, then virtually no worsening of the condition occurs. Eye drops or laser treatment can lower the eye pressure by moderating the outflow of aqueous, but these effects wear off in many patients. Successful surgery lowers the pressure more than eye drops or laser therapy, with considerable enhancement of quality-of-life including the elimination of eye drops. However surgery is associated with complications including (i) soft eye due too much aqueous outflow or (ii) high pressure due to localised scarring that prevents the flow of fluid out of the eye, causing progression of the underlying glaucoma. Surgical procedures to treat glaucoma include an operation to make a trapdoor drainage flap or implantation of a microtube device connected to a &ldquo;reservoir&rdquo; plate made of materials that result in scarring as it is too different from the surrounding tissues. Both these operations require a great deal of training, can take several hours, and are prone to complications to maintain low IOP. This proposal is to optimise the novel BioChannel device so that it is easy to insert (10-15 minutes under local anaesthetic). Because pressure control will be more stable with the BioChannel, it will have fewer complications than current treatment. The BioChannel is made of a special, soft biocompatible, tissue-like material that has been used in the human body for many years and is proven to be safe. The BioChannel mimics the tissues and aqueous flow of the eye and is much less likely to cause complications or progression of glaucoma.

Research activity codes: 5.3 MEDICAL DEVICES
Health categories: EYE