Excerpt

Diabetic retinopathy (DR) and diabetic macular edema (DME) are microvascular complications of diabetes that are a leading cause of blindness in the diabetic population. DME — which is swelling of the retina due to leakage of fluid from blood vessels within the macula, the central portion of the retina — may occur at any time during the progression of DR. The goal of treatment is to preserve current visual acuity and reduce the chances of progression to visual loss. Successful laser treatment reduces moderate visual loss but has limited effects on improving visual acuity. Intravitreal injection of corticosteroids, such as triamcinolone acetate, may also moderately improve visual acuity, but these generally offer only short-term improvements in acuity in cases of DME refractory to laser treatment. Moreover, triamcinolone is not licensed by Health Canada for this indication. Ranibizumab is a recombinant humanized monoclonal immunoglobulin G1 antibody that binds to and inhibits the biologic activity of human vascular endothelial growth factor (VEGF). It is the only pharmacological therapy licensed in Canada for the treatment of DME.

Bevacizumab (Avastin), also derived from a recombinant humanized monoclonal IgG1 antibody that inhibits VEGF, is used clinically in the treatment of DME, although it does not have a Notice of Compliance (NoC) from Health Canada for this indication. It is approved as an antineoplastic, not for the condition under consideration. This systematic review was undertaken to evaluate the effects of intravitreal bevacizumab for the treatment of diabetic macular edema.

Contents

• ACRONYMS AND ABBREVIATIONS
• EXECUTIVE SUMMARY
• 1. CONTEXT AND POLICY ISSUES
• 2. RESEARCH QUESTION
• 3. KEY MESSAGES
• 4. METHODS
  • 4.1 Literature Search Strategy
  • 4.2 Selection Criteria And Methods
  • 4.3 Exclusion Criteria
  • 4.4 Article Selection
  • 4.5 Data Extraction Strategy
  • 4.6 Critical Appraisal of Individual Studies
  • 4.7 Data Analysis Methods
• 5. RESULTS
  • 5.1 Quantity of Research Available
  • 5.2 Study Characteristics
  • 5.3 Data Analyses and Synthesis
  • 5.4 Critical Appraisal of Individual Studies
• 6. DISCUSSION
  • 6.1 Summary of Evidence
  • 6.2 Comparison With Other Literature
  • 6.3 Limitations
• 7. CONCLUSIONS AND IMPLICATIONS FOR DECISION- OR POLICY-MAKING
• REFERENCES
• APPENDIX 1 SUMMARY OF EVIDENCE ON ADVERSE EVENTS WITH INTRAVITREAL BEVACIZUMAB: A SUPPLEMENTAL SAFETY REVIEW
• APPENDIX 2 GLOSSARY OF SELECTED TERMS
• APPENDIX 3 LITERATURE SEARCH STRATEGY
• APPENDIX 4 SELECTION OF INCLUDED STUDIES (PREFERRED REPORTING ITEMS FOR SYSTEMATIC REVIEWS AND META-ANALYSIS [PRISMA] FLOW CHART)
• APPENDIX 5 LIST OF INCLUDED STUDIES
• APPENDIX 6 LIST OF EXCLUDED STUDIES
• APPENDIX 7 CHARACTERISTICS OF INCLUDED AND EXCLUDED STUDIES
• APPENDIX 8 CRITICAL APPRAISAL OF INCLUDED STUDIES
• APPENDIX 9 SUMMARY OF STUDY FINDINGS

Health technology assessment agencies face the challenge of providing quality assessments of medical technologies in a timely manner to support decision-making. Ideally, all important deliberations would be supported by comprehensive health technology assessment reports, but the urgency of some decisions often requires a more immediate response.

The Rapid Response Service provides Canadian health care decision-makers with health technology assessment information, based on the best available evidence, in a quick and efficient manner. Inquiries related to the assessment of health care technologies (drugs, devices, diagnostic tests, and surgical procedures) are accepted by the service. Information provided by Rapid Response Service is tailored to meet the needs of decision-makers, taking into account the urgency, importance, and potential impact of the request.

Consultations with the requestor of this Rapid Response assessment indicated that a review of the literature would be beneficial. The research question and selection criteria were developed in consultation with the requestor. The literature search was carried out by an information specialist using a standardized search strategy. The review of evidence was conducted by one internal reviewer. The draft report was internally reviewed and externally peer-reviewed by two or more peer reviewers. All comments were reviewed internally to ensure that they were addressed appropriately.

Production of this report is made possible by financial contributions from Health Canada and the governments of Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Nunavut, Prince Edward Island, Saskatchewan, and Yukon. The Canadian Agency for Drugs and Technologies in Health takes sole responsibility for the final form and content of this report. The views expressed herein do not necessarily represent the views of Health Canada, or any provincial or territorial government.

CADTH is funded by Canadian federal, provincial, and territorial governments.

Suggested citation:

Fortin, P., Mintzes, B., and Innes, M. A Systematic Review of Intravitreal Bevacizumab for the Treatment of Diabetic Macular Edema [Internet]. Ottawa: Canadian Agency for Drugs and Technologies in Health; 2012 (Rapid Response Report: Peer-Reviewed Summary with Critical Appraisal). Available from: http://www.cadth.ca/media/pdf/RD0028_avastin_L3_e.pdf

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