A combined analysis of two
landmark clinical glaucoma trials -- the Ocular Hypertension Treatment
Study (OHTS) and the European Glaucoma Prevention Study (EGPS) -- confirms
the benefit of a five-year risk assessment model to help ophthalmologists
better predict which patients have an increased risk of developing
glaucoma. Glaucoma is the second leading cause of blindness in the world,
affecting approximately 70 million people, and can lead to blindness if
left untreated. These new data were presented this week at the annual
American Academy of Ophthalmology meeting.
The analysis showed that patients with elevated intraocular pressure
(IOP) -- along with other predictive risk factors, such as older age (40+)
-- are at highest risk of progressing to primary open-angle glaucoma
(POAG). The results are similar to the 2005 risk-assessment model reported
by Dr. Robert N. Weinreb and Dr. Felipe A. Medeiros based on findings from
the 2002 Ocular Hypertension Treatment Study (OHTS), a five-year National
Eye Institute- sponsored trial that found early intervention with
IOP-lowering medications could prevent glaucoma in at-risk patients.
"It is critical to continue to evaluate and refine innovative,
predictive models in ophthalmic medicine in order to provide the best
treatment possible for patients," said Dr. Michael Kass. "We hope this tool
will become as universally adapted as predictive models used in other
therapeutic areas, such as the Framingham Study, which provided a basis for
accurate cardiac risk assessment."
"For some time we have known that if we could identify those patients
most likely to progress to glaucoma, earlier intervention with effective
treatments could help reduce the risk of vision impairment," said Dr.
Robert N. Weinreb, director of the Hamilton Glaucoma Center and
Distinguished Professor of Ophthalmology at the University of California,
San Diego, USA. "This new analysis provides a larger-scale validation of
breakthrough findings of the OHTS group and reinforces to clinicians how
the tool can be useful in assessing which patients are most at risk."
The OHTS prediction model was tested on patients in the EGPS placebo
group and the two study samples from the control (non-treated) arms were
pooled to increase precision and generalizability of a five-year predictive
model for developing POAG. The OHTS observation group contained 819
patients with a median follow up of every six months for 6.6 years. The
EGPS placebo group contained 500 patients with a median follow up of every
six months for 4.8 years.
"We know that awareness of these predictors, particularly elevated
intraocular pressure, and central corneal thickness, is critical in
treating and potentially preventing damage to the optic nerve caused by
glaucoma progression," said Professor Stefano Miglior, director of the
Department of Ophthalmology, Policlinico di Monza, University of Milan
Bicocca, Italy, and Chairman of EGPS. "The large-scale validation, which
includes a European patient population for the first time, reinforces the
consensus about the importance of informed dialogue between physicians and
patients on how often eye examinations are needed and when it might be
appropriate to initiate treatment."
The research was supported by grants from Pfizer Inc, the National Eye
Institute and the National Center for Minority Health and Health
Disparities, National Institutes of Health, the European Commission and
Research to Prevent Blindness and Merck Research Laboratories.
Pfizer's current product line includes the most prescribed treatment to
lower elevated eye pressure in patients with ocular hypertension
(abnormally high eye pressure) or open-angle glaucoma. In collaboration
with (OSI) Eyetech, the division also includes a treatment for neovascular.
CE Pfizer Inc
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