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Data From LALES Indicate Link Between Glaucoma and Diabetes
In the population-based, cross-sectional Los Angeles Latino Eye Study (LALES), the presence of type 2 diabetes (as well as a longer duration of the disease) was independently associated with a higher risk of open-angle glaucoma (OAG) among Latinos living in Los Angeles.1
Investigators found that 1,157 (19.6%) of 5,894 participants in the LALES had type 2 diabetes and 288 (4.9%) had OAG. Statistical analyses showed that the prevalence of OAG was 40% higher among individuals who had type 2 diabetes than those who did not have the systemic disease. In addition, the investigators noted that a history of diabetes of 15 years or longer was independently associated with an elevated risk for OAG.
The association between glaucoma and diabetes has long been debated in the ophthalmic literature and remains the subject of controversy, noted Vikas Chopra, MD, an investigator for the LALES, in an interview with Glaucoma Today. "Different studies have produced conflicting data regarding a positive or negative association between these conditions," he said. "These contradictory results may be due to the different methodologies and populations used by various studies."
The LALES is the first population-based study to report a higher risk of OAG with a longer duration of diabetes, Dr. Chopra added. This association is reasonable, he and his co-investigators wrote, because "diabetes is known to cause microvascular damage and may affect vascular autoregulation of the retina and optic nerve." A longer duration of diabetes, therefore, could cause "prolonged insult to the retina and optic nerve … [and] a higher risk of OAG."1
The relatively high prevalence of diabetes and OAG in the LALES' cohort could have implications for public health, the investigators warned, because both conditions are likely to become more common as the fast-growing Latino population ages.
"Additional studies, including longitudinal data, are needed to help resolve the controversy surrounding diabetes as a risk factor for OAG," Dr. Chopra told GToday. "In the meantime, we may have to modify screening programs and design healthcare plans to include additional testing for OAG in Latinos who have diabetes."
Novartis to Acquire Minority Stake in Alcon. Further Buys Possible
Following an announcement that Novartis International AG (Basel, Switzerland) intends to purchase 74 million shares of Alcon, Inc. (Huenenberg, Switzerland), common stock from Nestlé (Vevey, Switzerland), Novartis Chief Executive Daniel Vasella announced that the company could make more acquisitions in the future.
"One can assume that we will not do an acquisition on this scale and not in this area," Mr. Vasella said in an interview with a Swiss newspaper. "Medium-sized acquisitions … would certainly be possible." No specific acquisitions, however, are planned at the moment, he added.
If approved, the Alcon transaction will give Novartis an approximately 25% minority stake in the company. The deal stipulates that Nestlé will retain approximately 52% of Alcon's outstanding shares and remain the company's majority shareholder. Novartis will have the option to buy Nestlé's remaining shares of Alcon at a fixed price of $181 per share from January 1, 2010, to July 31, 2011. Nestlé will also have the option to sell its remaining stake in Alcon, either at that fixed price or a 20.5% premium above the market price of the shares for the preceding week on its option, whichever is lower, according to the announcement.
Additionally, the agreement calls for the expansion of Alcon's board of directors from eight to 10 members, with one additional member chosen by Nestlé and one by Novartis. The agreement is subject to regulatory approvals.
Company Suspends Development of Experimental IOP-Lowering Agent
Pfizer Inc. (New York, NY) announced that it will not pursue phase 3 clinical trials of PF-03187207, the experimental nitric oxide-donating formulation of latanoprost that the company codeveloped with NicOx SA (Sophia Antipolis, France), because the drug did not meet the primary endpoint of a phase 2 clinical trial.
PF-03187207 satisfied several secondary endpoints and consistently lowered IOP from baseline more effectively than latanoprost 0.005% at all visits and time points during the phase 2 dose-finding study. The experimental drug did not meet the study's primary endpoint, however, because its hypotensive effect was not statistically significantly better (approximately 1 mm Hg lower) than latanoprost's at the end of the 28-day trial.
Earlier this year, Pfizer initiated a phase 2, double-masked, dose-ranging clinical trial of PF-03187207 in Japan. The company stated in a news release that it would consider "continuing the development of PF-03187207 for potential registration in Asia, including Japan," depending on the results of the Japanese study.
Phacoemulsification May Be Underutilized for Treating Ocular Hypertension
During Glaucoma Subspecialty Day at this year's ASCRS meeting in Chicago, Brooks J. Poley, MD, and colleagues were recognized for presenting the best paper of the glaucoma surgical treatment session for their study of the IOP-lowering effect of phacoemulsification and IOL implantation in glaucomatous eyes.1
In a retrospective review of 124 eyes, those that had preoperative IOPs between 29 and 23 mm Hg (n = 17) experienced a greater reduction in IOP (-8.4 mm Hg) after phacoemulsification and IOL surgery than those who had lower preoperative IOPs (n = 84; preoperative range, 17 to 22 mm Hg; postoperative change, -1.1 to -4.6 mm Hg). The IOPs of eyes with preoperative pressures ranging from 5 to 14 mm Hg (n = 23) actually increased by 1.7 mm Hg after the removal of the crystalline lens.
The study's authors postulated that age-related changes in the crystalline lens compress the trabecular meshwork and Schlemm's canal and thus may cause ocular hypertension in older individuals. The removal of the lens thus might expand these structures, improve physiologic outflow from the anterior chamber, and prevent the progression of ocular hypertension to glaucoma.
Drug Delivery System Begins Clinical Trials
QLT, Inc. (Vancouver, British Columbia, Canada), is recruiting patients for a randomized, masked, parallel-group, phase 2 trial of its novel drug delivery system.
The "Core" study will evaluate the safety and efficacy of the company's Punctum Plug Delivery System, a noninvasive device designed to release latanoprost continually onto the ocular surface. During the 12-week investigation, approximately 60 patients with primary open-angle glaucoma will receive punctal plugs that deliver three different concentrations of latanoprost. The study's primary outcome measure will be the change in IOP from baseline.
In a small, 90-day, proof-of-concept, open-label study, the plug-based drug delivery system lowered the mean IOP in six eyes of six patients from 23 to 17 mm Hg.
QLT, Inc., purchased the Punctum Plug Delivery System from ForSight Newco II, Inc. (Menlo Park, CA), a spinout of the ophthalmic incubator ForSight Labs LLC (Menlo Park, CA), for $42 million in November 2007.
Company Acquires Experimental Drainage Device
Opko Health, Inc. (Miami, FL), has purchased Vidus Ocular, Inc. (New Haven, CT), a privately held company that is developing the Aquashunt. The experimental drainage device is designed to enhance the physiologic outflow of aqueous from glaucomatous eyes. According to the company, the device is composed of a biocompatible material that conforms to the shape of the eye, and it lowers IOP by draining aqueous humor from the anterior chamber to the suprachoroidal space. The design is intended to facilitate a "rapid, simple, minimally traumatic" insertion into the eye, says Opko.
Glaucoma Today spoke with the shunt's inventor, M. Bruce Shields, MD. Dr. Shields is Sears Professor and Chairman Emeritus of the Department of Ophthalmology and Visual Science at the Yale University School of Medicine in New Haven, Connecticut. In the interview, he compared the implantation of the Aquashunt to cyclodialysis, a surgical treatment for glaucoma that was introduced more than 100 years ago.
"During cyclodialysis, the surgeon inserts a spatula into the suprachoroidal space through a scleral incision," he said. "The spatula is then advanced into the anterior chamber to create a cleft through which aqueous can flow directly into the suprachoroidal space."
The shunt and its insertion tool replace the cyclodialysis spatula during the Aquashunt's implantation, Dr. Shields added. "Because the tip of the shunt is shaped like that of the spatula, it creates its own opening into the anterior chamber, thereby achieving a watertight closure around the shunt," he said. "The insertion tool also serves as an obturator within the shunt's lumen. After the tool is withdrawn, the shunt is secured to the sclera with a single suture."
Opko anticipates initiating a pilot trial of the Aquashunt in humans in the second half of 2008.
Online Educational Resource Highlights the Optic Nerve
The All Eyes on Glaucoma campaign launched the Optic Nerve Physician Resource Center during a breakfast meeting in Fort Lauderdale, Florida. The goal of the online educational resource is to raise physicians' awareness of the importance of evaluating the optic nerve for structural changes associated with early glaucoma and to increase the frequency of such examinations in clinical practice.
During the event, Robert N. Weinreb, MD, Distinguished Professor of Ophthalmology and Director, Hamilton Glaucoma Center at the University of California, San Diego, emphasized the importance of examining the optic nerve with slit-lamp biomicroscopy and a handheld lens. He also recommended that physicians use stereoscopic photographs, confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography to detect glaucoma and to track the disease's progression. "Structural and functional examination of the optic nerve are complementary and are integral for diagnosing and monitoring glaucoma," Dr. Weinreb commented.
For more information about the All Eyes on Glaucoma campaign and to access interactive case studies in the Optic Nerve Physician Resource Center, visit www.alleyesonglaucoma.com/English/Index.aspx.
The All Eyes on Glaucoma campaign is supported by Pfizer Inc. (New York, NY).
Update on Implantable IOP Monitors
Several posters presented at the annual ARVO meeting in Fort Lauderdale, Florida, described prototypic devices designed to monitor IOP continuously in glaucomatous eyes.
Investigators from Solx, Inc. (Waltham, MA), reported the results of ex vivo benchtop testing of a device that combines an integrated circuit, a capacitive power source, and a pressure sensor on a ceramic substrate. To recharge the device and download data, the patient would hold an external device near his eye once a day.
According to the investigators, the pressure sensor detected changes within the tested range with a simulated resolution of 2 mm Hg, and the device's individual components were functional. Nonetheless, they determined that further refinements (ie, additional miniaturization, improved biocompatibility, and greater sensitivity to fluctuations in IOP) are necessary. Solx anticipates completing a second prototype by September 2008 and initiating animal studies by October 2008.1
Assenti, LLC (Louisville, KY), is developing a wireless, implantable IOP monitor that reportedly runs without batteries and can be integrated into a pseudophakic or phakic IOL.2 According to the investigators, the device's Micro-Electro-Mechanical Systems capacitive pressure transducer exhibited a linear response of frequency versus pressure with a sensitivity of 0.5 mm Hg/Hz in the eye of a New Zealand white rabbit. Future studies will investigate the implant's long-term performance.
Investigators presented the results of the first in vivo test of the Contact Lens Sensor (Sensimed AG, Lausanne, France) in five healthy human volunteers.3 The device consists of strain gauges and a wireless antennae embedded in a soft silicone contact lens. It reportedly detects changes in the corneoscleral curvature induced by fluctuations in IOP and sends the data to an external reader.
The Contact Lens Sensor successfully detected elevated IOPs (induced by exposing the eye to depressurized conditions with a SCUBA mask for 10 minutes in five volunteers) with a sensitivity of 0.04 to 0.2 mV/mm Hg. The volunteers tolerated the contact lens and did not report any discomfort during the short test. Although the sensor's original signal was noisy due to blinking, the investigators were able to filter out the spike caused by this action to measure the participants' IOPs and ocular pulsation.
FDA Approves Application for Generic Glaucoma Drug
Hi-Tech Pharmacal Co., Inc. (Amityville, NY), has received tentative approval from the FDA to manufacture a generic version of Cosopt (dorzolamide hydrochloride and timolol maleate; Merck & Co., Inc., Whitehouse Station, NJ). The combined carbonic anhydrase inhibitor/beta-adrenergic receptor is indicated for the reduction of elevated IOP in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers.
Hi-Tech believes that it will have 180 days of marketing exclusivity for combined generic dorzolamide hydrochloride and timolol maleate. The company anticipates launching its new product upon the completion of Merck's pediatric exclusivity period in October 2008.
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