CANTREAT-Extension Study: Long-term Efficacy of a Treat-and-Extend Regimen of Ranibizumab in Patients With nAMD

15 Feb, 22

Introduction

Several trials have demonstrated the long-term efficacy of anti-vascular endothelial growth factor (anti-VEGF) therapy in maintaining the visual acuity (VA) in patients with neovascular age-related macular degeneration (nAMD). Nevertheless, reductions in the number of anti-VEGF injections over time, were associated with incremental loss of the VA gains originally achieved. Retina specialists are increasingly using the treat-and-extend (T&E) strategy for the management of nAMD patients.

Aim

The 12-month extension of the 2-year CANTREAT (Canadian Treat and Extend Analysis Trial with Ranibizumab) trial evaluated the long-term effectiveness of a T&E anti-VEGF regimen in patients with nAMD who remained on T&E and also in those switched from once-monthly (OM) dosing to T&E (OM-T&E).

Patient Profile

Treatment-na?ve patients with nAMD who had completed the CANTREAT study treatment period (n=139)

Methods

Study Design

A 12-month extension of the 2-year CANTREAT study
CANTREAT was a prospective, randomized and multicenter study

Treatment Strategy

Patients received intravitreal ranibizumab 0.5 mg in a T&E regimen

Outcomes

Mean change in best-corrected visual acuity (BCVA) from baseline and from month 24 to month 36
Percentages of patients who gained ≥5, ≥10, or ≥15 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters or lost ≥5, ≥10, or ≥15 letters from baseline and from month 24 to month 36
Number of injections administered from baseline and from month 24 to month 36 for both study groups

Results

Of the 139 CANTREAT patients (73 T&E, 66 OM-T&E) who participated in the extension phase, 121 (68 T&E, 53 OM-T&E) completed 36 months. The mean age of the study population was 79.1 years.
The mean BCVA changes from baseline to the extension last visit (month 33-36) were +6.6 letters in the T&E group and +4.8 letters in the OM-T&E group, representing maintenance of 24-month gains (Fig. 1).

Fig. 1: Mean BCVA change from baseline to extension last visit

Slightly more patients in the T&E group vs. OM-T&E group gained ≥15, ≥10, and ≥5 letters, and percentages were nearly similar (P=1.00) for ≥15- and ≥10-letter gains. Fewer T&E patients lost ≥15, ≥10, and ≥5 letters; but none of these differences were statistically significant.
The mean numbers of injections during the extension for T&E and OM-T&E groups were 7.3 and 7.1, respectively.
Nearly 47.9% patients in the T&E group and 48.5% patients in the OM-T&E group achieved a maximum treatment interval of 12 weeks, while 16.4% of T&E patients and 15.2% of OM-T&E patients achieved a maximum interval of <6 weeks.
There was a significant reduction in percentages of patients with any macular fluid from baseline to the last extension visit in both the study groups, the same being comparable with the 24-month results (Table 1).

Table 1: Percentage of patients with macular fluid during the study

Study Group	Baseline	Last Extension Visit
T&E Group	100%	28.2%
OM-T&E Group	100%	29.8%

Conclusions

The 12- and 24-month CANTREAT results demonstrated the effectiveness of a T&E ranibizumab regimen compared to an OM regimen with patients requiring significantly fewer injections.
This 12-month extension further demonstrated that these clinical benefits could be maintained up to 36 months, for patients on a continuous T&E regimen as well as for patients in OM switching to a T&E regimen.

Ophthalmology. Dec 30, 2021 (Published Online); DOI: 10.1159/000521517