CATT at 2 Years: The Facts

Charles C. Wykoff, MD, PhD; David M. Brown, MD


August 13, 2012

In This Article

Future Directions

As a medical community, we may anticipate a given trial's outcome on the basis of our clinical experience; however, it is imperative to keep prospective, trial-derived scientific data distinct from interpretation of such data and personal bias. The efficacy and safety results of both CATT and IVAN are fascinating, with more detailed analyses to follow. Unfortunately, the results comparing these 2 agents given on a monthly or as-needed basis are intricate and cannot be summarized in a single headline statement. Rather, these data underscore the importance of physician/patient discussions and the need for regular reassessment of informed consent with patients.

CATT and IVAN confirmed that both bevacizumab and ranibizumab are exceptionally effective in the treatment of neovascular AMD, and the primary endpoint of noninferiority between the 2 drugs was statistically achieved at 2 years when administered monthly in CATT and cumulatively at year 1 in IVAN. Secondary endpoint analysis leads to a more complex discussion; however, many indices suggest subtle differences between the medications. Ranibizumab seems to have greater biological activity than bevacizumab, and fewer injections may be required when it is administered on an as-needed basis.

In CATT, pooled data on as-needed dosing were inferior to those for monthly treatment, a finding supported by results from HARBOR. The clinical relevance of this mean 2.4-letter difference in CATT is debatable. Comparison of monthly and as-needed dosing at the primary endpoint in IVAN at 2 years will be interesting.

In the face of these scientific data, cost is important. Despite potentially less biological activity with bevacizumab and a compromise in mean visual gains with as-needed therapy, bevacizumab given either as needed or monthly certainly provides the most letters gained per dollar spent. This economic reality may be particularly important in countries or healthcare systems with limited resources. How the introduction of additional anti-VEGF pharmaceuticals, such as the FDA-approved fusion protein aflibercept,[19] that may extend intervals between treatments will alter neovascular AMD treatment is yet to be defined.


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