Clinical trial NCT00336323: A Phase 2 Evaluation of Anti-VEGF Therapy for Diabetic Macular Edema: Bevacizumab (Avastin)
Official title: A Phase 2 Evaluation of Anti-VEGF Therapy for Diabetic Macular Edema: Bevacizumab (Avastin)
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Diabetic Retinopathy
Keywords: diabetic
macular
edema
avastin
bevacizumab
anti-VEGF
retinal thickness
visual acuity
DME
Lead sponsor: Jaeb Center for Health Research
Sponsor class: OTHER
Collaborators: name: National Eye Institute (NEI)
First posted: 2006-06-13
Enrollment: 121
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: This study will provide preliminary data on the dose and dose interval related effects of intravitreally administered Avastin on retinal thickness and visual acuity in subjects with Diabetic Macular Edema (DME) to aid in planning a phase 3 trial.

In addition, this study will provide preliminary data on the safety of intravitreally administered Avastin in subjects with DME.

Detailed description: Diabetic retinopathy is a major cause of visual impairment in the United States. Diabetic macular edema (DME) is a manifestation of diabetic retinopathy that produces loss of central vision. Data from the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) estimate that after 15 years of known diabetes, the prevalence of diabetic macular edema is approximately 20% in patients with type 1 diabetes mellitus (DM), 25% in patients with type 2 DM who are taking insulin, and 14% in patients with type 2 DM who do not take insulin.

In a review of three early studies concerning the natural history of diabetic macular edema, Ferris and Patz found that 53% of 135 eyes with diabetic macular edema, presumably all involving the center of the macula, lost two or more lines of visual acuity over a two year period. In the Early Treatment Diabetic Retinopathy Study (ETDRS), 33% of 221 untreated eyes available for follow-up at the 3-year visit, all with edema involving the center of the macula at baseline, had experienced a 15 or more letter decrease in visual acuity score (equivalent to a doubling of the visual angle, e.g., 20/25 to 20/50, and termed "moderate visual loss").

In the ETDRS, focal photocoagulation (direct treatment to microaneurysms and grid treatment to diffuse edema) of eyes with clinically significant macular edema (CSME) reduced the risk of moderate visual loss by approximately 50% (from 24% to 12%, three years after initiation of treatment). Therefore, 12% of treated eyes developed moderate visual loss in spite of treatment. Furthermore, approximately 40% of treated eyes that had retinal thickening involving the center of the macula at baseline still had thickening involving the center at 12 months, as did 25% of treated eyes at 36 months.

Although several treatment modalities are currently under investigation, the only demonstrated means to reduce the risk of vision loss from diabetic macular edema are laser photocoagulation, as demonstrated by the ETDRS, intensive glycemic control, as demonstrated by the Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) and blood pressure control, as demonstrated by the UKPDS. In the DCCT, intensive glucose control reduced the risk of onset of diabetic macular edema by 23% compared with conventional treatment. Long-term follow-up of patients in the DCCT show a sustained effect of intensive glucose control, with a 58% risk reduction in the development of diabetic macular edema for the DCCT patients followed in the Epidemiology of Diabetes Interventions and Complications Study.

The frequency of an unsatisfactory outcome with respect to proportion with vision improvement following laser photocoagulation in some eyes with diabetic macular edema has prompted interest in other treatment modalities. One such treatment is pars plana vitrectomy. These studies suggest that vitreomacular traction, or the vitreous itself, may play a role in increased retinal vascular permeability. Removal of the vitreous or relief of mechanical traction with vitrectomy and membrane stripping may be followed by substantial resolution of macular edema and corresponding improvement in visual acuity. However, this treatment may be applicable only to a specific subset of eyes with diabetic macular edema that have a component of vitreomacular traction contributing to the edema. It also requires a complex surgical intervention with its inherent risks, recovery time, and expense. Other treatment modalities such as pharmacologic therapy with oral protein kinase C inhibitors and use of intravitreal corticosteroids are under investigation. The use of antibodies targeted at vascular endothelial growth factor (VEGF), such as in the current study, is another treatment modality that has generated considerable interest, and is currently being investigated in phase 3 trials of choroidal neovascularization in age-related macular degeneration (with pegaptanib or ranibizumab) or diabetic macular edema (with pegaptanib).

Increased VEGF levels have been demonstrated in the retina and vitreous of human eyes with diabetic retinopathy. VEGF, also known as vascular permeability factor, has been demonstrated to increase vessel permeability by increasing the phosphorylation of tight junction proteins, and has been shown to increase retinal vascular permeability in in vivo models. Anti-VEGF therapy, therefore, may represent a useful therapeutic modality which targets the underlying pathogenesis of diabetic macular edema.

Bevacizumab is currently approved for the treatment of metastatic colorectal cancer, and published case reports and widespread clinical use have suggested its efficacy in the treatment of neovascular age-related macular degeneration and macular edema associated with diabetes and central retinal vein occlusion. To date, no evidence of ocular inflammation or other adverse events has been noted in association with intravitreal injection of bevacizumab. However, a study has not been conducted to evaluate its efficacy and safety. In view of the widespread use of bevacizumab, such a study is important to conduct.

From a public health perspective, an intravitreal bevacizumab study is also important to conduct because of the relatively low cost of the bevacizumab drug. As noted earlier, bevacizumab is marketed for systemic use for colon cancer. The dose used in the eye is a fraction of the systemic dose and costs $25 to $50 per dose.

The two doses of bevacizumab being evaluated in this study will be 1.25 mg, which is the dose that has most commonly been used in clinical practice, and 2.5 mg, which has also been used though less commonly. A lower dose than 1.25 mg would create difficulties with dilution and the accuracy of injection of a small volume.

The optimal interval for the bevacizumab doses is not known. Six weeks has been selected for this study as it is not believed that the effect will last longer than this. Retinal thickening and visual acuity will be measured at 3 and 6 weeks to provide the requisite information to judge the duration of effect.

There is expected to be a beneficial cumulative effect of multiple doses. A total of two doses, spaced 6 weeks apart, was selected for the study with the primary outcome 3 weeks after the second dose.

The decision as to whether to proceed to a phase 3 trial will be based on the observation of a substantial reduction in retinal thickening in the bevacizumab-treated eyes compared with the laser-treated eyes and at least a suggestion of benefit on visual acuity, plus a safety profile of minimal risk.

Description: The study involves the enrollment of subjects over 18 years of age with diabetic macular edema. Subjects will have one study eye randomly assigned with equal probability (stratified by visual acuity) to one of 5 treatment groups:

Laser photocoagulation at baseline

1.25 mg intravitreal injection of bevacizumab at baseline and 6 weeks

2.5 mg intravitreal injection of bevacizumab at baseline and 6 weeks

1.25 mg intravitreal injection of bevacizumab at baseline (sham injection at 6 weeks)

1.25 mg intravitreal injection of bevacizumab at baseline, laser photocoagulation at 3 weeks, and intravitreal injection of 1.25 mg bevacizumab at 6 weeks

Follow-up includes 10 visits at 4 days, 3 weeks, 6 weeks, 4 days following 6 weeks, 9 weeks, 12 weeks, 18 weeks, 24 weeks, 41 weeks and 70 weeks. At each visit, visual acuity and ocular exams are completed on both eyes, and an OCT is performed on the study eye (except at the 4-day visits).

During the first 12 weeks, no other treatment for DME is given. During weeks 13-24, treatment depends on the response to the treatment given during the first 12 weeks. After 24 weeks, follow-up is for safety and treatment is at the investigator's discretion.

Eligibility criteria: SUBJECT-LEVEL INCLUSION CRITERIA

To be eligible, the following inclusion criteria (1-3) must be met:

1. Age \>= 18 years
2. Diagnosis of diabetes mellitus (type 1 or type 2)
3. Able and willing to provide informed consent.

   EXCLUSION

   A subject is not eligible if any of the following exclusion criteria (4-13) are present:
4. Significant renal disease, defined as a history of chronic renal failure requiring dialysis or kidney transplant.
5. A condition that, in the opinion of the investigator, would preclude participation in the study (e.g., unstable medical status including blood pressure, cardiovascular disease, and glycemic control).
6. Participation in an investigational trial within 30 days of randomization that involved treatment with any drug that has not received regulatory approval at the time of study entry.
7. Known allergy to any component of the study drug.
8. Blood pressure \> 180/110 (systolic above 180 OR diastolic above 110).
9. Major surgery within 28 days prior to randomization or major surgery planned during the next 6 months.
10. Myocardial infarction, other cardiac event requiring hospitalization, stroke, transient ischemic attack, or treatment for acute congestive heart failure within 6 months prior to randomization.
11. Systemic anti-VEGF or pro-VEGF treatment within 3 months prior to randomization.
12. For women of child-bearing potential: pregnant or lactating or intending to become pregnant within the next 6 months.
13. Subject is expecting to move out of the area of the clinical center to an area not covered by another clinical center during the first 6 months of the study.

STUDY EYE CRITERIA

The subject must have one eye meeting all of the inclusion criteria (a-e) and none of the exclusion criteria (f-r) listed below.

Subjects can have only one study eye. If both eyes are eligible, the study eye will be selected by the investigator and subject.

The eligibility criteria for a study eye are as follows:

INCLUSION

1. Best corrected E-ETDRS visual acuity letter score of \>= 24 (i.e., 20/320 or better) and \<= 78 (i.e., 20/32 or worse) within 8 days of randomization.
2. On clinical exam, definite retinal thickening due to diabetic macular edema involving the center of the macula.
3. OCT central subfield \>=275 microns within 8 days of randomization.
4. Media clarity, pupillary dilation, and subject cooperation sufficient for adequate fundus photographs.
5. If prior macular photocoagulation has been performed, the investigator believes that the study eye may possibly benefit from additional photocoagulation.

   EXCLUSION

   The following exclusions apply to the study eye only (i.e., they may be present for the nonstudy eye):
6. Macular edema is considered to be due to a cause other than diabetic macular edema.
7. An ocular condition is present such that, in the opinion of the investigator, visual acuity would not improve from resolution of macular edema (e.g., foveal atrophy, pigmentary changes, dense subfoveal hard exudates, nonretinal condition).
8. An ocular condition is present (other than diabetes) that, in the opinion of the investigator, might affect macular edema or alter visual acuity during the course of the study (e.g., vein occlusion, uveitis or other ocular inflammatory disease, neovascular glaucoma, Irvine-Gass Syndrome, etc.).
9. Substantial cataract that, in the opinion of the investigator, is likely to be decreasing visual acuity by 3 lines or more (i.e., cataract would be reducing acuity to 20/40 or worse if eye was otherwise normal).
10. History of treatment for DME at any time in the past 3 months (such as focal/grid macular photocoagulation, intravitreal or peribulbar corticosteroids, anti-VEGF drugs, or any other treatment).
11. History of panretinal scatter photocoagulation (PRP) within 4 months prior to randomization.
12. Anticipated need for PRP in the 6 months following randomization.
13. History of prior pars plana vitrectomy.
14. History of major ocular surgery (including cataract extraction, scleral buckle, any intraocular surgery, etc.) within prior 6 months or anticipated within the next 6 months following randomization.
15. History of YAG capsulotomy performed within 2 months prior to randomization.
16. Aphakia.
17. Uncontrolled glaucoma (in investigator's judgment).
18. Exam evidence of external ocular infection, including conjunctivitis, chalazion, or significant blepharitis.

FELLOW EYE CRITERIA

The fellow eye must meet the following criteria:

1. Best corrected E-ETDRS visual acuity letter score \>= 19 (i.e., 20/400 or better).
2. No anti-VEGF treatment within the past 3 months and no expectation of such treatment in next 3 months.

Primary outcomes:
measure: Change in Central Subfield Retinal Thickness From Baseline Over All Study Visits
timeFrame: Baseline to 3,6,9, and 12 weeks
measure: Percentage of Participants With <250 Microns or ≥ 50% Reduction in Retinal Thickening From Baseline Over All Study Visits
timeFrame: Baseline to 3,6,9, and 12 Weeks
Secondary outcomes:
measure: Change in Visual Acuity Letter Score From Baseline Over All All Study Visits
timeFrame: Baseline to 3,6,9, and 12 weeks
measure: Distribution of Change in Visual Acuity Over All Study Visits
timeFrame: Baseline to 3,6,9, and 12 weeks
Other outcomes:
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Baseline Central Subfield Thickness
timeFrame: Baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Baseline Visual Acuity Letter Score
timeFrame: Baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Age at Baseline
timeFrame: Baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Gender
timeFrame: Baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to History of Treatment for Diabetic Macular Edema at Baseline
timeFrame: Baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Retinopathy Severity at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Clinical Diabetic Macular Edema Characterization at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Central Subfield Thickness in Bevacizumab Groups From Baseline to 3 Weeks According to Subretinal Fluid Presence at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Central Subfield Thickness at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Visual Acuity at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Age at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Gender
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to History of Treatment for Diabetic Macular Edema
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Retinopathy Severity at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Clinical Diabetic Macular Edema Characterization at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Visual Acuity (Letters) in Bevacizumab Groups From Baseline to 3 Weeks According to Subretinal Fluid Presence at Baseline
timeFrame: baseline to 3 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 1.25mg Injection Only and Had a >11% Decrease in Change of Central Subfield Thickness From Baseline to 3 Weeks
timeFrame: 3 to 6 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 1.25mg Injection Only and Had Within a ±11% Change of Central Subfield Thickness From Baseline to 3 Weeks
timeFrame: 3 to 6 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 1.25mg Injection Only and Had a >11% Increase in Change of Central Subfield Thickness From Baseline to 3 Weeks
timeFrame: 3 to 6 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 2.5mg Bevacizumab and Had a >11% Decrease in Change of Central Subfield Thickness From Baseline to 3 Weeks
timeFrame: 3 to 6 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 2.5mg Bevacizumab and Had Within a ±11% Change in Central Subfield Thickness From Baseline to 3 Weeks
timeFrame: 3 to 6 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 2.5mg Bevacizumab and Had a >11% Increase in Change of Central Subfield Thickness From Baseline to 3 Weeks
timeFrame: 3 to 6 Weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 1.25mg Bevacizumab at 6 Weeks and Had a >11% Decrease in Change of Central Subfield Thickness From 6 Weeks to 9 Weeks
timeFrame: 3 to 9 weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 1.25mg Bevacizumab at 6 Weeks and Had Within ±11% Change of Central Subfield Thickness From 6 Weeks to 9 Weeks
timeFrame: 3 to 9 weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 1.25mg Bevacizumab at 6 Weeks and Had a >11% Increase in Change of Central Subfield Thickness From 6 Weeks to 9 Weeks
timeFrame: 3 to 9 weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 2.5mg Bevacizumab at 6 Weeks and Had a >11% Decrease in Change of Central Subfield Thickness From 6 Weeks to 9 Weeks
timeFrame: 3 to 9 weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 2.5mg Bevacizumab at 6 Weeks and Had Within ±11% Change of Central Subfield Thickness From 6 Weeks to 9 Weeks
timeFrame: 3 to 9 weeks
measure: Change in Central Subfield Thickness From 3 to 6 Weeks Among Eyes That Received 2.5mg Bevacizumab at 6 Weeks and Had Within >11% Increase in Change of Central Subfield Thickness From 6 Weeks to 9 Weeks
timeFrame: 3 to 9 weeks
Locations:
city: Loma Linda
country: United States
facility: Loma Linda University Health Care, Dept. of Ophthalmology
state: California
city: Palm Springs
country: United States
facility: Southern California Desert Retina Consultants, MC
state: California
city: Santa Barbara
country: United States
facility: California Retina Consultants
state: California
city: Walnut Creek
country: United States
facility: Bay Area Retina Associates
state: California
city: Ft. Lauderdale
country: United States
facility: Retina Vitreous Consultants
state: Florida
city: Lakeland
country: United States
facility: Central Florida Retina Institute
state: Florida
city: Augusta
country: United States
facility: Southeast Retina Center, P.C.
state: Georgia
city: Joliet
country: United States
facility: Illinois Retina Associates
state: Illinois
city: Indianapolis
country: United States
facility: Raj K. Maturi, M.D., P.C.
state: Indiana
city: New Albany
country: United States
facility: American Eye Institute
state: Indiana
city: Lexington
country: United States
facility: Retina and Vitreous Associates of Kentucky
state: Kentucky
city: Paducah
country: United States
facility: Paducah Retinal Center
state: Kentucky
city: Bangor
country: United States
facility: Maine Vitreoretinal Consultants
state: Maine
city: Baltimore
country: United States
facility: Elman Retina Group, P.A.
state: Maryland
city: Salisbury
country: United States
facility: Retina Consultants of Delmarva, P.A.
state: Maryland
city: Boston
country: United States
facility: Ophthalmic Consultants of Boston
state: Massachusetts
city: Boston
country: United States
facility: Joslin Diabetes Center
state: Massachusetts
city: Minneapolis
country: United States
facility: Retina Center, PA
state: Minnesota
city: Charlotte
country: United States
facility: Charlotte Eye, Ear, Nose and Throat Assoc., PA
state: North Carolina
city: Winston-Salem
country: United States
facility: Wake Forest University Eye Center
state: North Carolina
city: Beachwood
country: United States
facility: Retina Associates of Cleveland, Inc.
state: Ohio
city: Portland
country: United States
facility: Retina Northwest, PC
state: Oregon
city: Portland
country: United States
facility: Casey Eye Institute
state: Oregon
city: Hershey
country: United States
facility: Penn State College of Medicine
state: Pennsylvania
city: Providence
country: United States
facility: Retina Consultants
state: Rhode Island
city: Columbia
country: United States
facility: Palmetto Retina Center
state: South Carolina
city: Columbia
country: United States
facility: Carolina Retina Center
state: South Carolina
city: Knoxville
country: United States
facility: Southeastern Retina Associates, P.C.
state: Tennessee
city: Abilene
country: United States
facility: West Texas Retina Consultants P.A.
state: Texas
city: Austin
country: United States
facility: Retina Research Center
state: Texas
city: Dallas
country: United States
facility: Texas Retina Associates
state: Texas
city: Houston
country: United States
facility: Charles A. Garcia, PA & Associates
state: Texas
city: Lubbock
country: United States
facility: Texas Retina Associates
state: Texas
city: Seattle
country: United States
facility: University of Washington Medical Center
state: Washington
Study officials:
affiliation: Penn State College of Medicine
name: Ingrid U. Scott, M.D., M.P.H.
role: STUDY_CHAIR
References:
citation: Diabetic Retinopathy Clinical Research Network; Scott IU, Edwards AR, Beck RW, Bressler NM, Chan CK, Elman MJ, Friedman SM, Greven CM, Maturi RK, Pieramici DJ, Shami M, Singerman LJ, Stockdale CR. A phase II randomized clinical trial of intravitreal bevacizumab for diabetic macular edema. Ophthalmology. 2007 Oct;114(10):1860-7. doi: 10.1016/j.ophtha.2007.05.062. Epub 2007 Aug 15.
citation: Scott IU, Bressler NM, Bressler SB, Browning DJ, Chan CK, Danis RP, Davis MD, Kollman C, Qin H; Diabetic Retinopathy Clinical Research Network Study Group. Agreement between clinician and reading center gradings of diabetic retinopathy severity level at baseline in a phase 2 study of intravitreal bevacizumab for diabetic macular edema. Retina. 2008 Jan;28(1):36-40. doi: 10.1097/IAE.0b013e31815e9385.
citation: Bhavsar AR, Ip MS, Glassman AR; DRCRnet and the SCORE Study Groups. The risk of endophthalmitis following intravitreal triamcinolone injection in the DRCRnet and SCORE clinical trials. Am J Ophthalmol. 2007 Sep;144(3):454-6. doi: 10.1016/j.ajo.2007.04.011.