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Loading dose necessary with most intravitreal injection treatments, surgeon says
WAILEA, Hawaii — A loading dose of at least three monthly injections gives the best visual and anatomic results when working with intravitreal injections, a surgeon said here.
 Peter K. Kaiser |
"The loading dose appears to be important," Peter K. Kaiser, MD, said at Retina 2009. "This, to me, indicates that we really need to do that loading dose, at least with VEGF Trap (Regeneron Pharmaceuticals/Bayer HealthCare), and I've personally taken that to also mean for bevacizumab and ranibizumab."
Dr. Kaiser showed data from the VEGF Trap studies in which the groups that received four monthly injections before as-needed treatment had higher initial spikes in visual acuity gain and greater initial reductions in central retinal thickness. These initial reactions were maintained throughout the study.
Conversely, the other groups received injections every 12 weeks and did not reach the same levels as the groups with monthly dosing either in initial reaction or throughout the study.
Previous studies of ranibizumab therapy with alternative dosing schedules (i.e., PIER, PRONTO) included initial monthly injections for the first 3 months (i.e. “loading doses”) followed by less than monthly dosing, but these studies did not specifically look at the value of the loading dose. There has been some suggestion that these 3 “loading doses” are not necessary in all patients, because at least 1/3 of treated eyes will respond favorably to the first dose. To date, there has been no clinical evidence comparing outcomes in eyes who received 3 loading doses prior to an alternative dosing schedule and those that went into the alternative dosing schedule with less than 3 loading doses.
Such a study was performed in the VEGF trap trial and showed that the eyes that received 4 loading doses of VEGF trap fared better than those that went right into an “as needed” dosing schedule. Dr. Kaiser suggests that this data be extrapolated to ranibizumab and bevacizumab therapy for now, until there is clinical evidence to suggest otherwise.
– Jay S. Duker, MD
OSN Retina/Vitreous Board Member