Effect of Macugen(Pegaptanib)on Surgical Outcomes and VEGF Levels in Diabetic Patients With PDR (Diabetic Retinopathy or CSDME (Macular Edema) (PEGAP001)
|The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.|
|ClinicalTrials.gov Identifier: NCT00446381|
Recruitment Status : Completed
First Posted : March 12, 2007
Last Update Posted : April 19, 2012
|Condition or disease||Intervention/treatment||Phase|
|Proliferative Diabetic Retinopathy Diabetic Macular Edema||Drug: Macugen (pegaptanib) Drug: Macugen (Pegaptanib)||Not Applicable|
Diabetes is one of the leading causes of blindness in North America. Diabetic retinopathy (PDR) is characterized by disruption of the normal microvascular circulation in the retina and results in the production of neovascularization and increased microvascular permeability. Similarly, clinically significant diabetic macular edema CSDME) results in loss of central visual acuity.
Many patients with these conditions, despite treatment, will go on to develop vitreous hemorrhage or tractional changes that require surgical intervention (such)as vitrectomy and/or vitrectomy with membrane peeling in the attempt to both restore vision and prevent further visual loss or re-establish the normal macular anatomy and improve patient visual acuity.
Although multiple etiologic factors are involved in the early changes seen in diabetic retinopathy and maculopathy, it has been shown that VEGF is the primary angiogenic growth factor implicated in the development of neovascularization in PRD and in increased vascular permeability, resulting in CSDME. VEGF levels have been found to correlate tightly with the extent of diabetic retinopathy and introduction of VEGF into normal primate eyes can induce diabetic retinopathy. Although several isoforms of VEGF exist, isoform 165 (VEGF 165) is the most pathogenic form of VEGF and therefore inhibition of VEGF 165 may play a significant role in modulating diabetic retinopathy and maculopathy.
Macugen is a VEGF antagonist (anti-VEGF pegylated aptamer) which binds to VEGF 165 with high specificity and affinity. In vitro pharmacology studies have shown that Macugen binds to the amino acid isoform VEGF 165 and inhibits it from binding to its cellular receptors. As a consequence, Macugen blocks signalling events and disrupts the cascade of proliferative and vascular permeability responses associated with the binding of VEGF 165 to endothelial cells. This effect has been clearly proven in Phase 3 trials for patients with age-related macular degeneration (AMD), resulting in inhibition of vascular development and decrease in vascular leakage.
Although diabetic retinopathy represents a different challenge than AMD, the underlying pathogenic factors are similar in the role and effects of VEGF. Regression of retinal neovascularization after Macugen therapy in diabetic individuals has been shown. Phase 2 studies have been completed and Phase 3 studies are currently underway in patients with diabetic macular edema to evaluate the efficacy of Macugen to restore vision in patients with CSDME. These studies are ongoing but exclude patients in whom vitrectomy has been performed or is planned in the near future due to tractional effects on the macula from epiretinal membranes or vitreomacular traction syndrome. No studies have been done to date in patients with PDR or CSDME to quantify the reduction of intravitreal VEGF 165 levels in these patients following intravitreal Macugen injection or to evaluate the effects of VEGF 165 blockade on the neovascular regression and surgical outcome in patients with extensive diabetic proliferative neovascularization.
The goal of this study is to quantify the reduction of intravitreal VEGF 165 levels in patients following intravitreal Macugen injection pre-operatively and determine the level of Macugen in the vitreous cavity after variable time intervals (2,4, 6 or 8 weeks).
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||28 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Official Title:||Effect of Macugen (Pegaptanib) on Surgical Outcomes and Growth Factors Including Vascular Endothelial Growth Factor (VEGF) Levels in Patients With Proliferative Diabetic Retinopathy (PDR) and Clinically Significant Diabetic Macular Edema (CSDME)|
|Study Start Date :||October 2006|
|Actual Primary Completion Date :||September 2008|
|Actual Study Completion Date :||September 2008|
Patients with Proliferative Diabetic Retinopathy
Drug: Macugen (pegaptanib)
Pegaptanib 0.3 mg by intravitreal injection once pre-operatively
Patients with Clinically Significant Macular Edema
Drug: Macugen (Pegaptanib)
Pegaptanib 0.3 mg by intravitreal injection once pre-operatively.
- Levels of intravitreal Macugen post injection of intravitreal Macugen. [ Time Frame: 2 to 8 weeks ]
- Levels of intravitreal VEGF 165 pre and post injection of intravitreal Macugen. [ Time Frame: 0 to 8 weeks ]
- Levels of intravitreal VEGF, TGFbeta, ET-1, PDGF, IGF-1,angiopoietin, HIF 1 alpha, HIF 1 beta pre and post injection of intravitreal Macugen. [ Time Frame: 0 to 8 weeks ]
- Effect on ease of surgery post injection of intravitreal Macugen. [ Time Frame: 2 to 8 weeks ]
- Effect on re-bleed rate post injection of intravitreal Macugen. [ Time Frame: 0 to 8 weeks ]
- Effect on concomitant diabetic macular edema post injection of intravitreal Macugen [ Time Frame: 0 to 8 weeks ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00446381
|Ivey Eye Institute, St. Joseph's Health Care Centre|
|London, Ontario, Canada, N6A 4G5|
|Principal Investigator:||Thomas G. Sheidow, MD||Ivey Eye Institute, St. Joseph's Health Care Centre|