Clinical Studies:

CATT: Two-Year Outcomes

Summarized by Landon Rohowetz, MD (Bascom Palmer Eye Institute)

Citations: Martin DF, Maguire MG, Comparison of Age-related Macular Degeneration Treatments Trials Research Group, et al. Ranibizumab and bevacizumab for treatment of neovascular age-related macular degeneration: two-year results. Ophthalmology. 2012; 119(7): 1388-1398.

Key Points

  • The CATT trial was a randomized controlled trial comparing the efficacy of bevacizumab and ranibizumab when administered on a monthly and as-needed basis.
  • Patients were randomly assigned to groups defined by drug and dosing regimen. At 1 year, patients on monthly regimens were randomly reassigned to monthly or as-needed regimens. Outcomes were evaluated at 2 years.
  • There was no difference in visual acuity gain between ranibizumab and bevacizumab (bevacizumab-ranibizumab difference, −1.4 letters; 95% CI, −3.7 to 0.8). Monthly regimens resulted in greater visual acuity gain than as-needed regimens (difference, 2.4 letters; 95% CI, 4.8 to 0.1). The prevalence of retinal fluid was less in the ranibizumab and monthly regimens.
  • Switching to an as-needed regimen after one year of a monthly regimen resulted in a greater decrease in vision and a lower proportion of patients without fluid when compared with patients who continued to receive monthly injections.
  • Patients who received bevacizumab experienced a higher rate of serious adverse events than patients who received ranibizumab (39.9% vs. 31.7%). However, the significance of this finding is uncertain given the lack of specificity of the observed events with VEGF inhibition.
  • Objective:

    Randomized controlled trial comparing the efficacy and safety of intravitreal bevacizumab and ranibizumab administered as monthly or as-needed regimens at two years.


    Multicenter, single-blind randomized controlled trial.


Major inclusion criteria:


Patients were initially assigned to one of four study groups based on drug (bevacizumab or ranibizumab) and dosing regimen (monthly or as-needed) using permuted block randomization. At 1 year, patients in the monthly groups were randomly reassigned to either monthly or as-needed treatment with no change in drug assignment.

RESULTS (2 years)

Study population

Follow-up time


Visual acuity end-points

Anatomic outcomes

Adverse Events