Intravitreal aflibercept superior to eye laser for diabetic retinopathy at 1 year
Intravitreal injection of the anti-VEGF* agent aflibercept shows superior visual acuity outcomes over panretinal laser photocoagulation (PRP) at 1 year in eyes with active proliferative diabetic retinopathy (PDR) without diabetic macular oedema, according to the CLARITY** study.
Although PRP has been the standard of care in PDR management for the past 40 years, “PRP has substantial side effects, including reduced visual field and colour vision, and exacerbation of diabetic macular oedema. Furthermore, 15 percent of eyes with PDR continue to lose vision … despite PRP,” according to Drs Daniel Ting Shu Wei and Wong Tien Yin from Singapore National Eye Centre in a separate commentary. [Lancet 2017;doi:10.1016/ S0140-6736(17)31194-7]
At 52 weeks, aflibercept was both noninferior and superior to PRP in terms of best-corrected visual acuity (mean difference, 3.9 letters; p<0.0001), a finding also supported by the per-protocol analysis (mean difference, 4.0; p<0.001). [Lancet 2017;doi:10.1016/S0140-6736(17)31193-5]
Additional sensitivity analyses taking into account of sites (p<0.0001), removal of outliers (p<0.0001), and missing data confirmed superiority in favour of aflibercept in both the intention-to-treat and per-protocol populations.
“[This] was achieved with a median of one aflibercept injection only in the 40 weeks’ post-loading phase [in addition to three injections during the loading phase], indicating that aflibercept is a feasible new approach for compliant patients,” said the researchers, highlighting the difference from the seven injections required within the first year with another anti-VEGF agent, ranibizumab.
“Despite the good visual outcomes reported with [aflibercept], … acceptance among clinicians might vary because PRP is perceived to have a permanent effect and requires fewer follow-up visits than does anti-VEGF therapy,” the researchers noted. “However, our study shows that 65 percent of the patients in the PRP group required supplemental PRP when monitored every 8 weeks over 52 weeks.”
In terms of PDR-related complications, the aflibercept group had a lower incidence of vitreous haemorrhage than the PRP group (9 percent vs 18 percent; p=0.034). There were also fewer patients requiring vitrectomy (1 percent vs 6 percent; p=0.066) or developing macular oedema (0 percent vs 2 percent; p=0.50) in the aflibercept vs PRP groups, although the differences were not statistically significant.
“[W]hen choosing between anti-VEGF and PRP as a first-line option in PDR … the findings of this study indicate that aflibercept [which has been licensed for diabetic macular oedema] is also effective in the management of PDR in the first year, allowing the use of a single drug to address both of these sight-threatening complications of diabetes,” suggested the researchers.
However, seeing that trial patients are usually different from those in the real-world setting, who are often active, working adults or with multiple comorbidities, Ting and Wong said, “These factors might limit enthusiasm for the intensive anti-VEGF treatment regimen offered.”
“Clinics offering anti-VEGF therapy as the standard of care for PDR would require a robust system to monitor, track, and enhance compliance in patients with PDR,” they added.
The single-blind, noninferiority phase IIb trial randomized 221 patients with type 1 or 2 diabetes, who had previously untreated or postlaser treated active PDR, to receive intravitreal aflibercept (2 mg/0.05 mL at baseline, repeated every 4 weeks thereafter, and from week 12 injections were given as needed after patient review every 4 weeks) or PRP (single spot or multispot laser at the start, divided fortnightly thereafter, and from week 12 PRP was performed as needed after assessing patients every 8 weeks) for 52 weeks.
“[T]he introduction of anti-VEGF therapy as the standard of care is promising, but more research is clearly needed to carefully assess the long-term visual, anatomical, safety, and cost-effectiveness outcomes,” said Ting and Wong.