According to a post on Medscape Medical News, oral pazopanib has been shown to produce improvements in visual acuity, central retinal lesion thickness, and central retinal thickness in some patients with age-related macular degeneration, this according to a small trial published online in JAMA Ophthalmology.
Possible alternative to frequent intravitreal injections for AMD
Frequent intravitreal injections can be quite stressful to patients. Researchers at GlaxoSmithKline studied investigational products with alternative delivery routes. According to lead author Megan M. McLaughlin of the JAMA article, “Pazopanib is a potent antiangiogenic that inhibits the same pathway as the intravitreal antivascular endothelial growth factor [VEGF] standard of care by inhibiting the receptor instead [of] inhibiting the ligand. Studies predicted that doses of pazopanib lower than that used to treat cancer may be effective in AMD and that lower doses were also likely to be better tolerated in the elderly AMD population.”
Vision improved in some patients
Tolerability of oral pazopanib was good at all doses tested in healthy participants and at 15 mg daily in patients with AMD. There were no clinically relevant effects on blood pressure, liver function, or thyroid function in the small study at lower doses, whereas doses of 800 mg typically used with cancer patients can have negative side effects.
Preliminary findings may warrant further study
“The limited sample size and short follow-up are two of the main limitations of this study when assessing for safety and efficacy,” Sumit P. Shah, MD, vitreoretinal surgeon at Retina Vitreous Center, NJ Retina, Rutgers, and Robert Wood Johnson University Hospital in New Brunswick, New Jersey, told Medscape Medical News when asked for independent comment. “Longer-term studies are warranted to assess both safety and efficacy of oral pazopanib, focusing on the pharmacogenetic efficacy findings of this study.”
“If oral pazopanib is shown to be an effective adjunctive therapy, even if only in a subset of patients, this may lessen the high level of treatment burden that most patients currently face with monthly injections or monthly follow-up,” Dr. Shah said. “It is possible that this therapy could be used as an adjunct to the current standard of care.”
The investigators suggest that the subset of patients with AMD most likely to benefit from pazopanib would be those carrying a T allele of CFH, representing approximately 70% of white individuals and 99% of East Asian individuals. On the basis of their preliminary findings, they suggest that additional trials may be warranted.
“The treatment will unlikely completely supplant the use of intravitreal injections but would likely be used as an adjunct to intravitreal injection therapy,” coauthor Mike Tolentino, MD, director of the Center for Retina and Macular Disease in Winter Haven, Florida, told Medscape Medical News. “It may have the potential to be used as the sole treatment in patients with early onset wet AMD…. It also should be tested to see if it can be used to maintain eyes that have been stabilized by intravitreal injections and are receiving injections in order to prevent recurrence.”
Without alternative treatments, wet AMD could become one of the most expensive diseases for our healthcare systems
“The rapidly increasing elderly population and the subsequent increase in the incidence of wet macular degeneration will strain the resources of our healthcare system, which is already being burdened with the leading edge of the baby boom generation,” Dr. Tolentino concluded. “If an alternative to intravitreal injections is not developed, wet AMD will become one of the most expensive diseases for our healthcare systems, both from a financial and societal perspective. Twenty years ago, when I was with the team that developed anti-VEGF therapies, we felt that intravitreal injections would be an intermediary treatment on the path to either an oral or eyedrop formulation [and] were never meant to be the final solution for the treatment of retinal diseases.”
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Excerpted with permission from Barclay L; AMD: Oral Pazopanib May Improve Vision, Retinal Thickness; Medscape; published October 11, 2013; available at: http://www.medscape.com/viewarticle/812492. Please note that a free, one-time registration is required in order to view the entire article and all other content on the Medscape site.
Tom Cockley is president of Gulden Ophthalmics and is the third generation of the nearly 75-year-old visionary company that brings innovative, time-saving, utilitarian products to vision and health care professionals.