Description

Age-related macular degeneration (AMD) accounts for 8.7% of all causes of blindness worldwide and is the most common cause of blindness in developed nations. Its prevalence is likely to increase as a consequence of exponential population ageing. Wet, or neovascular, AMD affects 10-15% of AMD patients and is characterised by macular neovascularisation (MNV), where new immature blood vessels grow towards the outer retina, typically from the underlying choroid, result in leakage, fluid accumulation, and haemorrhage. Faricimab is a bispecific antibody that acts through dual inhibition of both angiopoietin-2 and vascular endothelial growth factor A (VEGF-A). Safety and efficacy of intravitreal faricimab were evaluated in phase 3 trials in patients with nAMD. TENAYA and LUCERNE assessed faricimab administered at individualised treatment intervals of up to every 16 weeks compared with aflibercept given every 8 weeks in patients with nAMD.

Different treatment regimens exist, including the pro re nata (PRN) and the treat and extend (T&E) approaches. Treating macular disease with anti-VEGF has been an enormous burden to ophthalmic services globally. In Hong Kong, anti-VEGF treatment is self-financed, hindering access for the underprivileged. It has been mentioned that most public hospitals in the region are less likely to adopt a T&E regimen directly after the loading phase but are more inclined towards PRN regimen because of limited manpower and resources .

Generally, three monthly or four-weekly anti-VEGF injections before the introduction of faricimab to the public hospitals in Hospital Authority (HA) in 2023 would be arranged for newly diagnosed patients with nAMD during the initial visit at our institution. Depending on the treatment response, the patient would either be advised to stop injections (PRN regimen), to T&E regimen by extending the intervals in a stepwise manner, or be put on regular quarterly maintenance injections.

From the full prescribing information supplied by the manufacturer Roche, for nAMD, the recommended dose for Vabysmo® (Faricimab) is 6 mg (0.05 mL of 120 mg/mL solution) administered by intravitreal injection every 4 weeks (approximately every 28 ± 7 days, monthly) for the first 4 doses (at Weeks 0, 4, 8, 12), followed by optical coherence tomography (OCT) and visual acuity evaluations 8 and 12 weeks later to inform whether to give a 6 mg dose via intravitreal injection on one of the following three regimens: 1) Weeks 28 and 44 (every 16 weeks); 2) Weeks 24, 36 and 48 (every 12 weeks); or 3) Weeks 20, 28, 36 and 44 (every 8 weeks). Although additional efficacy was not demonstrated in most patients when Vabysmo® was dosed every 4 weeks compared to every 8 weeks, some patients may need every 4 week (monthly) dosing after the first 4 doses. Patients should be assessed regularly.

As this new drug, faricimab, is becoming available in the hospital authority (HA) in Hong Kong, it is expected to be more extensively given to our patients with nAMD. It is understood from the full prescribing information supplied by Roche that the injection interval can be extended up to 16 weeks. It is vital to have the knowledge whether some less treatment intensive, simple fixed regimen in our locality is comparable to the more intensive dosing suggested by the manufacturer. With the number of injections administered in the territory exponentially rising in recent years due to the ageing population, there is clearly a need to explore better alternatives to the PRN approach and this forms the basis of our study.