Baseline characteristics and treatment response predictive of nAMD outcomes with ranibizumab therapy in treatment-naive patients: the RACER subgroup analysis

BACKGROUND: The Ranibizumab AMD Clinical Efficacy Study (RACER) conducted in treatment-naive adult Taiwanese patients with neovascular age-related macular degeneration (nAMD) suggested the importance of early and intensive dosing of ranibizumab for optimal treatment outcomes. This subgroup analysis aims to provide clinical information on treatment response that can potentially guide on maintaining the treatment or switching anti-VEGF agents in the real-world setting. METHODS: Visual acuity (VA) and central retinal thickness (CRT) were assessed in the RACER subgroup population. Subgroup analysis sets were categorised based on: (1) baseline best-corrected VA (BCVA; ≤ 48 and > 48 letters); (2) baseline CRT (≤ 325 or > 325 μm); and (3) treatment response after three monthly initial injections: < or ≥ 5-letter gain in BCVA and reduction of < or ≥ 50 μm in CRT. RESULTS: Patient age, sex, nAMD duration and number of ranibizumab injections did not differ significantly between the treatment subgroups. Poor baseline BCVA (≤ 48 letters) and baseline CRT severity (> 325 µm) were predictors of maximum BCVA gains (9.6 ± 12.9 letters [95%CI: 6.3 to 12.9] and 5.1 ± 18.3 letters [95%CI: − 0.5 to 10.8] at Months 3 and 12, respectively) and better CRT reductions (− 127.6 ± 104.2 µm and − 104.2 ± 107.4 µm at Months 3 and 12, respectively; both P < 0.001). For the subgroup showing favourable treatment improvement with BCVA gains ≥ 5 letters after three monthly initial injections, 75.6% of patients maintained follow-up at Month 12 with a mean of 6.5 ± 14.3 letter gains (95% CI: 1.2 to 11.7). The BCVA gains < 5-letter subgroup nevertheless had stable BCVA (0.4 ± 12.1 letter gains) and CRT (− 41.9 ± 61.2 µm) at Month 12, respectively. In the subgroup with ≥ 50 µm CRT reduction after three monthly initial injections, there are significantly higher BCVA improvements vs. the < 50 µm CRT reduction subgroup at Month 3 (5.0 ± 8.6 letter gains vs. 1.5 ± 11.6 letter gains, respectively; intergroup P = 0.005). CONCLUSION: Lower baseline BCVA and higher baseline CRT were associated with BCVA gains and CRT reductions throughout the 12-month study period. Early CRT improvements after three monthly initial injections were associated with BCVA gains as early as Month 3. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12886-023-02780-0.