HIGH-DOSE INTRAVITREAL TOPOTECAN (100 µ G/0.1 CC) AS MONOTHERAPY FOR RECURRENT/REFRACTORY INTRAOCULAR RETINOBLASTOMA...

To report the outcomes and safety of 100 μ g/0.1 cc intravitreal topotecan (IVitT100) as monotherapy for refractory/recurrent intraocular retinoblastoma.

Retrospective single-center study of 7 patients with retinoblastoma who received IVitT100 as monotherapy between January 2024 and December 2024 with a minimum follow-up of 3 months after the last injection.

At presentation, six eyes were classified as Group D and one as Group C, according to the International Classification of Retinoblastoma. High-dose topotecan was administered for refractory and recurrent disease in 2 (29%) and 5 (71%) eyes, respectively. The active disease was in the form of a intraretinal tumor with vitreous seeds (n = 3, 43%), intraretinal tumor with epiretinal seeds (n = 1, 14%), isolated intraretinal tumor (n = 1, 14%), isolated subretinal seeds (n = 1, 14%), or isolated vitreous seeds (n = 1, 14%). At a mean follow-up of 7 months (median, 6 months; range, 3-10) from the last injection of IVitT00, tumor control was achieved in 100% (4 of 4) eyes with vitreous seeds, 100% (1 of 1) with epiretinal seeds, 100% (1 of 1) with subretinal seeds, and 60% (3 of 5) with retinal tumor. Overall, tumor control was achieved in 5 eyes (71%) with IVitT100 monotherapy. Additional treatments were warranted in two eyes for complete tumor control. Globe salvage was achieved in all eyes (100%). The electroretinogram (n = 4) showed no significant changes compared with the baseline.

IVitT100 is a safe option for refractory or recurrent intraocular retinoblastoma and holds promise for controlling refractory vitreous seeds, subretinal seeds, and intraretinal tumors.