Quarterly Dosing of Conbercept Similar to Treat-and-Extend Regimen for PCV

Professor Xiaoxin Li

A treat-and-extend (TAE) strategy and a fixed dosing regimen of intravitreal conbercept each improved visual and anatomical outcomes in the management of polypoidal choroidal vasculopathy (PCV), according to new research.

The findings from the open-label, randomized phase 4 STAR study suggested that intravitreal conbercept was associated with significant improvements in patients with PCV with an acceptable safety profile and no significant differences in outcomes.

“Our study demonstrated that the 3 + TAE regimen can achieve comparable BCVA improvement with the 3 + Q12W regimen at week 48 for patients with PCV,” wrote study author Professor Xiaoxin Li, Xiamen Eye Center, Xiamen University.

A subtype of neovascular age-related macular degeneration (nAMD), PCV is particularly prevalent among populations in Asia and is estimated to account for nearly 50% of nAMD cases in Asia. The advent of anti-vascular endothelial growth factor (VEGF) monotherapy has superseded photodynamic therapy as first-line therapy for nAMD and subsequently has been favorable for active PCV.

Previous study data has suggested the benefit of conbercept for PCV, but there is a lack of data regarding the optimal treatment strategy for use in clinical practice. Its need for frequent injection may present a challenge with compliance with therapy in a real-world setting. The STAR study was conducted at 32 eye centers in China to compare the efficacy and safety of two different treatment regimens of intravitreal conbercept for PCV.

Patients in STAR were randomly assigned 1:1 to either a fixed dosing group (3 monthly loading doses followed by mandated injections every 12 weeks; 3 + Q12W group) and a treatment-and-extend group (3 monthly loading doses followed by a treat-and-extend administration based on disease activity; 3 + TAE group). All patients received the 3 consecutive intravitreal injections of 0.5 mg conbercept every 4 weeks in the loading phase.

The fixed-dosing cohort received mandated injections every 12 weeks with a last injection at week 44, with monthly monitoring and additional interval rescue injections given if necessary.  Patients in the treat-and-extend group received injections every 4 weeks until disease activity had resolved and best-corrected visual acuity (BCVA) was stable, with extension of the visit and treatment interval by 2 weeks based on disease activity.

A total of 455 patients were screened and 304 patients met the identified eligibility criteria and were thus enrolled in the study. At Week 48, 249 patients (123 in the 3 + Q12W and 126 in the 3 + TAE) were included in the per-protocol set for analysis of efficacy. The baseline age of patients was 64 years, 154 patients (61.9%) were male, and the average BCVA was 61.0 letters.

In 48 weeks of follow-up, the mean number of intravitreal conbercept was 6.6 ± 0.9 in the 3 + Q12W group and 9.4 ± 2.0  in the 3 + TAE group. Within the 3 + TAE group, data show 43.7% (n = 55) of patients were extended at the earliest possible visit or within 1 additional visit and 27.8% (n = 35) of patients were maximally extended. At Week 48, 61.1% (n = 77) of patients in the 3 + TAE group were at an extension interval of 8 weeks or more, with a mean maximum extension interval of 9.6 ± 2.0 weeks.

Moreover, at the 48-week mark, the mean BCVA improvement from baseline was 5.18 ± 16.24 letters in the 3 + Q12W group and 6.29 ± 13.23 letters in the 3 + TAE group. The findings indicated there was no significant difference in mean BCVA improvement between the two groups at week 48 (P  = .421).

Additionally, at week 48, the mean CRT decreased by 94.4 ± 151.5 μm in the 3 + Q12W group and 105.1 ± 143.9 μm in the 3 + TAE group. There were no significant differences observed in CRT change at week 48 between the two groups (P = .818).

Investigators reported there were no significant differences between the two treatment groups in maximum retinal thickness (P = .448), pigment epithelial detachment (PED) height (P = .221), PED volume (P = .076), branching vascular network (BVN) area (P = .615), polypoidal lesion number (P = .701), and polypoidal lesion area (P = .424). No differences were reported in the rates of patients who avoided vision loss of ≥15 letters (P = .397) or complete polypoidal lesion regression rate (43.8% vs. 41.8%; P = .814).

The study, “The comparison of two different strategies of intravitreal conbercept for polypoidal choroidal vasculopathy in Chinese patients results from a 48-week randomized phase 4 study: STAR study,” was published in Acta Ophthalmologica.