VIENNA — Results of DRCR.net Protocol T may signal a paradigm shift in the treatment of diabetic macular edema, but are scarcely applicable to the European clinical context, where ranibizumab is marketed and used at a higher 0.5 mg concentration, a specialist told colleagues here.
“Protocol T showed superior efficacy of aflibercept, particularly in the group of patients with more severe disease. However, the 0.3 mg ranibizumab concentration used in the study is the one registered for the U.S. market, which is nearly half the concentration we use in Europe,” Francesco Bandello, MD, said at the meeting of the European Society of Ophthalmology.
Ranibizumab is marketed as Lucentis (Genentech/Novartis) and aflibercept is marketed as Eylea (Regeneron/Bayer).
“Understandably, Novartis reacted by saying that the evidence shown in the study cannot be considered significant for Europe. Bayer, on the other hand, argued that studies using two different concentrations of ranibizumab did not show significantly different outcomes between groups.”
In clinical practice, both ranibizumab and aflibercept are used with comparably good results by European surgeons, he said. However, with both drugs the rate of non-responders remains high, around 30% to 40%.
“We should look more into the pathogenesis and mechanisms of DME, which might vary from patient to patient. We need a classification system to help us select the appropriate treatment for individual patients, whether anti-VEGF, steroids, laser or combinations,” Bandello said.
The wider spectrum of causative factors addressed by steroids probably explains why steroids have more widespread efficacy, with a significantly lower number of non-responders, he said. – by Michela Cimberle
Disclosure: Bandello is a consultant to Alcon, Bayer and Novartis.