Outer Retinal Tubulation as a Predictor of the Growth Rate of Geographic Atrophy in Age-related Macular Degeneration

Program Number: 5885 Poster Board Number: C0071 Presentation Time: 8:30 AM–10:15 AM Outer Retinal Tubulation as a Predictor of the Growth Rate of Geographic Atrophy in Age-related Macular Degeneration Amirhossein Hariri1, Muneeswar G. Nittala1, Srinivas R. Sadda1, Eric C. Strauss2, Phillip Lai2, Erin Henry2. 1Doheny Eye Institute, Los Angeles, CA; 2Genentech Inc., South San Francisco, CA. Purpose: To determine whether the presence of outer retinal tubulation (ORT) predicts the growth of geographic atrophy (GA) lesions in eyes with age-related macular degeneration (AMD). Methods: The MAHALO study (NCT01229215) enrolled 143 subjects into a Phase Ib/II multicenter, randomized, single-masked, sham-injection controlled clinical trial of the safety, tolerability and evidence of activity of lampalizumab in patients with GA associated with AMD. Spectral domain optical coherence tomography (SD-OCT, Cirrus OCT) images were evaluated with baseline and Month 18 data of fellow (non-study) eyes for this exploratory analysis. Area of GA was automatically computed using the OCT instrument software and segmentation errors were manually corrected. The change in GA area between baseline and Month 18 was computed. In addition, baseline OCT volume scans were inspected for the presence of ORT. The GA growth rate (with and without square root transformation (SQRT)) was compared between eyes with and without ORT. Results: 103 fellow eyes with GA secondary to AMD, and OCT data at baseline and M18 were included in this study. 24 eyes showed evidence of ORT; in these eyes with ORT, the mean and median total area of GA was 7.94 and 7.75 mm2 at baseline, and increased to 9.62 and 9.85 mm2 at M18. In the 79 eyes without evidence of ORT, the mean and median total area of GA was 6.27 and 6.10 mm2 at baseline and increased to 8.67 and 9.30 mm2 at M18. Despite a larger baseline GA size, eyes with ORT showed a lower growth rate than eyes without ORT (1.68 ± 0.93 vs 2.40 ± 1.54, P=0. 003). This effect of ORT was observed regardless of whether the GA lesion was unifocal or multifocal (Table 1). Conclusions: The growth rate of GA is slower in eyes with evidence of outer retinal tubulation on OCT compared to those without this finding. Commercial Relationships: Amirhossein Hariri, None; Muneeswar G. Nittala, None; Srinivas R. Sadda, Allergan (C), Carl Zeiss Meditec (C), Genentech (C), Optos (C); Eric C. Strauss, Genentech (E); Phillip Lai, Genentech (E); Erin Henry, Genentech (E)