Abstract
Purpose:
To simulate a hypothetical switch from ranibizumab (RBZ) to another anti-vascular endothelial growth factor by investigating long-term functional outcomes of patients treated with RBZ 0.5 mg who experienced an initial loss of best-corrected visual acuity (BCVA,) within or immediately after the first three, monthly loading doses in diabetic macular edema trials.
Methods:
A first analysis was conducted in patients from RETAIN (http://clinicaltrials.gov, NCT01171976 registered 07-27-2010, trial start 09-2010; n=372) and RESTORE Extension (n=166) who were treated with RBZ 0.5 mg pro re nata (PRN) or treat and extend (TE), with or without (+/-) adjunctive laser, and who lost 4 or more letters from baseline (BL) to month (M) 1 and/or M2. A second analysis included patients from RESTORE, REVEAL, RETAIN and RESPOND (n=445, pooled data set), treated with RBZ 0.5 mg PRN monotherapy and who lost 4 or more letters from BL to M4, M5 and M6.
Results:
In RESTORE Extension, 11 of 83 (13.3%) and 9 of 83 (10.8%) patients from the RBZ monotherapy and RBZ +/- laser arms, respectively, lost 4 or more letters from BL to M1 and/or M2. Subsequently, the RBZ monotherapy patients gained a mean of 8.8, 11.4 and 13.7 letters from the first visit with BCVA loss to M12, M24 and M34, respectively; the respective gains for the RBZ +/- laser arms were 7.3, 11.1 and 10.1 letters. In RETAIN, 16 of 133 (13.7 %), 15 of 128 (12%) and 11 of 123 (9.4%) patients in the TE +/- laser, TE monotherapy and PRN monotherapy arms, respectively, lost 4 or more letters from BL to M1 and/or M2. From the first visit with BCVA loss, these three arms gained a mean of 9.1, 7.2 and 9.9 letters to M12, and 11.0, 12.4 and 12.4 letters to M23, respectively. In the pooled analysis, 9 (2%) patients treated with RBZ PRN lost 4 or more letters from BL to M4, M5, and M6; these patients regained a mean of 11.2 letters from M6 to M12.
Conclusions:
These post-hoc analyses revealed a low number of patients treated with RBZ PRN or TE who experienced vision loss within 2 months after treatment initiation, or within 3 months after completion of the loading phase. These patients gained on average 2 lines at 12M and maintained the gains over the long term. These delayed responders benefited from continuing RBZ 0.5 mg treatment; if therapy was switched, such patients would need to gain in excess of 10-12 letters over 12-24 months to benefit.