One-Year Efficacy and Safety of Proton-Beam Irradiation Combined with Intravitreal Conbercept for Refractory or Recurrent Polypoidal Choroidal Vasculopathy: A Pilot Study

INTRODUCTION: To investigate the efficacy and safety of proton-beam irradiation (PBI) combined with intravitreal conbercept (IVC) injection for refractory or recurrent polypoidal choroidal vasculopathy (PCV). METHODS: A prospective interventional clinical trial included 12 patients with refractory PCV (defined as persistent exudation or fluid after six consecutive injections at monthly intervals and/or photodynamic therapy) or recurrent PCV (defined as new exudative signs after six monthly injections and/or photodynamic therapy) treated between January 2019 and September 2020. Every patient underwent single PBI (14 GyE) with concomitant IVC (0.5 mg) within 1 week and further doses of IVC were administered pro re nata. RESULTS: By the 12-month follow-up, the subretinal fluid was completely absorbed in 9 eyes (81.8%). The angiographic regression and closure rates of the polyps were 60% (12/20) and 90% (18/20), respectively. The mean number of IVC injections was 3.1 ± 1.37. The mean BCVA improved by 20 letters (P = 0.006). The mean central macular thickness (CMT) decreased from 476.50 ± 123.63 μm to 317.70 ± 89.34 μm (P = 0.004). The areas of branching vascular networks and polyps decreased by 37.2% and 72.3%, respectively. Radiation retinopathy was observed in five eyes, but no systemic adverse events were observed. CONCLUSION: PBI combined with IVC appears to promote polyp regression and closure, reduce CMT, and improve BCVA, with a favorable safety profile, after 12 months. Therefore, PBI may be a useful adjuvant therapy for patients with refractory or recurrent PCV. TRIAL REGISTRATION: Proton-Beam Irradiation Combined with Intravitreal Conbercept for Refractory or Recurrent Polypoidal Choroidal Vasculopathy: Prospective Phase II Clinical Study (ChiCTR2000038987).