Safety and Efficacy of Multiple Escalating Doses of RC28-E for Neovascular Age-Related Macular Degeneration: A Phase 1b Trial

Abstract Introduction To assess the safety and efficacy of repeated intravitreal injections of RC28-E, a novel bispecific antibody that simultaneously binds vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in patients with neovascular age-related macular degeneration (AMD). This was a prospective, multicenter, open-label clinical trial; 37 patients with choroidal neovascularization secondary to AMD and best-corrected visual acuity (BCVA) letter scores between 73 and 34 were enrolled. Methods Treatment regimens consisted of a 3-month loading phase and a pro re nata (PRN) maintenance phase. This study included three treatment groups: the 0.5, 1.0, and 2.0 mg RC28-E groups, with escalating doses ranging from 0.5 to 2.0 mg. Patients were evaluated monthly for 48 weeks. Safety was assessed based on ocular and systemic adverse events (AEs), pharmacokinetic characteristics, and the presence of anti-RC28-E antibodies. Efficacy was assessed using the mean change in BCVA and central subfield thickness (CST) from baseline to week 48. Results Most AEs were mild or moderate. The most common AE was a minor injection-related subconjunctival hemorrhage (16.2%). The AEs did not increase with dose or repeated injections. At week 48, mean improvements in BCVA from baseline in the 0.5, 1.0, and 2.0 mg groups were 6.1 ± 8.3, 9.9 ± 10.7, and 7.6 ± 9.38 letters, respectively; mean reductions in CST in the three groups were 112.1 ± 160.5, 175.1 ± 212.4, and 128.7 ± 145.8 μm, respectively. The serum RC28-E concentrations in 95% of the patients were below the quantification limit of the assay. No significant change from baseline was observed in the mean plasma concentrations of VEGF or FGF over the 48 weeks of treatment. Pre-treatment antibodies to RC28-E were detected in 1 of the 37 patients. Antibodies to RC28-E were detected in two patients after dosing with RC28-E for 48 weeks. Conclusion RC28-E was well tolerated and exhibited an overall favorable safety profile with evidence of improvements in BCVA and anatomical parameters.