Influence of treatment parameters on selectivity of verteporfin therapy

To improve selectivity of verteporfin therapy (PDT) in neovascular age-related macular degeneration (AMD) using modified treatment parameters.

Nineteen consecutive patients with predominantly classic choroidal neovascularization (CNV) in AMD were treated with 6 mg/m2 verteporfin given as bolus infusion. Patients received PDT with a fluence of either 25 or 50 J/cm2. Choroidal perfusion changes were evaluated by indocyanine green angiography (ICGA) at baseline, day 1, week 1, week 4, and month 3. Secondary outcomes were CNV closure rate and therapy-induced leakage documented by fluorescein angiography (FA). The safety of the treatment was assessed with ETDRS visual acuity.

Complete CNV closure was achieved in all patients at day 1. Choroidal hypoperfusion was minimal in eyes treated with a reduced fluence of 25 J/cm2. Most patients treated with 50 J/cm2 showed significant choriocapillary nonperfusion at week 1, lasting as long as 3 months. A transient PDT-induced increase in leakage area in FA at day 1 was found to be more extensive in the 50-J/cm2 group.

Bolus administration of verteporfin combined with a reduced light dose achieved improved selectivity of photodynamic effects, avoiding collateral alteration of the physiologic choroid while obtaining complete CNV closure. An increased selectivity with decreased effect on the surrounding choroid should be of advantage in verteporfin monotherapy as well as in combination strategies.