Subgroup analysis suggests TTT benefit in eyes presenting with poor vision

May 4, 2005

A subgroup analysis from the Transpupillary Thermotherapy of Occult Subfoveal Choroidal Neovascular Membranes in patients with Age-Related Macular Degeneration (TTT4CNV) study shows an increasingly beneficial effect of TTT over time in eyes with BCVA of 20/100 or worse, said Elias Reichel, MD.

May 4

- Fort Lauderdale, FL - A subgroup analysis from the Transpupillary Thermotherapy of Occult Subfoveal Choroidal Neovascular Membranes in patients with Age-Related Macular Degeneration (TTT4CNV) study shows an increasingly beneficial effect of TTT over time in eyes with BCVA of 20/100 or worse, said Elias Reichel, MD.

Patients eligible for the TTT4CNV trial had subfoveal occult CNV with a maximum diameter of 3 mm and visual acuity of 20/50 to 20/400. They were randomized 2:1 to TTT (800 mW for 60 seconds with a 3-mm spot size) or sham treatment. One retreatment only was allowed after 3 months, according to the investigatorís discretion.

Previously reported intent-to-treat analysis results for the entire enrolled cohort of 305 patients found no statistically significant difference between TTT and sham study groups for the primary efficacy endpoint (avoidance of moderate vision loss). However, based in part on the observation of trends favoring treatment, various subgroup analyses were undertaken. Results from other CNV treatment studies and case series of TTT provided further rationale for studying the subgroup with baseline visual acuity of 20/100 or worse.

The subgroup analyses showed eyes treated with TTT had significantly less mean visual acuity loss and a significantly higher proportion had improved visual acuity. Trends favoring treatment were noted in analyses of avoidance of moderate and severe vision loss. From a safety perspective, there was no difference between groups in rates of severe vision loss at 1 month post-treatment.

"These subgroup analyses indicate that TTT is beneficial compared to natural history in eyes with subfoveal occult CNV and BCVA of 20/100 or worse in patients who also meet the other key eligibility criteria of this clinical trial," Dr. Reichel said.