High Dose Aflibercept in Diabetic Macular Edema in Patients With Previous Vitrectomy

Patients with diabetic macular edema (DME) sometimes must undergo vitrectomy surgery (PPV) for diabetic and non-diabetic related issues. Patients may have improved DME with anti-VEGF therapy and ranibizumab has been found to reduce central macular thickness (CMT) with anti-VEGF therapy following vitrectomy. Those patients still require intravitreal injections but the pharmacokinetics of a vitrectomized eye are different than those eyes that have not undergone vitrectomy. The clearance of protein molecules is quicker in vitrectomized eyes so these patients may be more refractory to standard of care anti-VEGF therapy. In rabbit models, the half-life of both bevacizumab and ranibizumab were reduced by a factor 1.8 and 1.3, respectively, after pars plana vitrectomy. In a study examining intravitreal triamcinolone acetonide in human eyes, the half-life was found to be 18.6 days in non-vitrectomized eyes and 3.2 days in vitrectomized eyes, but there was considerable intrasubject variation. Patients with various disease states, including neovascular age-related macular degeneration (nAMD) have been managed with monthly anti-VEGF therapy successfully after vitrectomy surgery. Another study performed by the DRCR net showed that patients with DME treated with anti-VEGF are not affected in the long term if they had had a previous vitrectomy. High dose aflibercept may improve anatomic and visual outcomes in this patient population. Also, high dose aflibercept may allow for longer treatment intervals in these vitrectomized eyes.