Pegaptanib sodium for acute retinal necrosis‐induced macular oedema

Editor, A 35-year-old immunocompromised woman with umbilical cord blood transplantation for adult lymphoma presented with a 2-week history of redness and blurred vision in both eyes following initial herpes zoster encephalitis. Examination revealed vitritis, retinal whitening (Fig. 1), vasculitis and optic nerve head oedema. Best-corrected visual acuity (BCVA) was 20/40 right eye (OD) and 20/60 left eye (OS). Optical coherence tomography (OCT) showed no cystoid macular oedema (CMO). Funduscopic image of the right eye showing one foci of retinal necrosis in the periphery in a 35-year-old immunocompromised woman with acute retinal necrosis secondary to varicella zoster virus. Polymerase chain reaction testing of the aqueous fluid revealed varicella zoster virus and the patient was diagnosed with bilateral acute retinal necrosis (ARN). The retinitis was controlled with oral valacyclovir and intravitreal foscarnet (2.4 mg) every 3 days, followed 10 days later by pars-plana vitrectomy and endolaser in both eyes. BCVA improved to 20/25 OD and 20/20 OS with no signs of ocular inflammation. One month later, the clinical course was complicated by severe CMO in the right eye with a central foveal thickness of 410 μm and a BCVA of 20/60, with no signs of ocular inflammation. After discussion of periocular and/or intravitreal use of steroids, the patient refused to have this treatment because of his family history of glaucoma and the increased potential risk of cataract formation. After a lengthy discussion of the potential risks and benefits of off-label intravitreal bevacizumab or intravitreal pegaptanib sodium use, the patient requested intravitreal pegaptanib sodium. An intravitreal injection of pegaptanib sodium (Macugen; Eyetech/Pfizer, New York, NY, USA) was administered in the right eye without complication. Two weeks after injection, OCT demonstrated a marked improvement of the macular oedema, with a central foveal thickness of 197 μm and a BCVA of 20/25 in the right eye (Fig. 2). Three months after treatment, there was no ocular inflammation and the OCT revealed no CMO. Optical coherence tomography (OCT) showing severe cystoid macular oedema in a 35-year-old immunocompromised woman with acute retinal necrosis secondary to varicella zoster virus (A). Two weeks after intravitreal injection of pegaptanib sodium, OCT demonstrated marked improvement of the macular oedema (B). Acute retinal necrosis (ARN) syndrome is a distinct infectious retinitis caused by members of the herpes virus family that can impair vision. It occurs mostly in adult patients, especially those severely immunocompromised, in association with a reactivation of a herpes virus infection (Lau et al. 2007). Active vasculitis is characterized by vascular sheathing and perivascular intraretinal haemorrhages. Vessel obstruction affects the central retinal artery more often than the vein and is a contributing factor to severe vision loss (Chang & Young 2007). Retinal ischaemia is the major trigger of vascular endothelial growth factor (VEGF) over-expression; it can lead to chronic inflammation and the development of retinal neovascularization (Nishijima et al. 2007). Active inflammation secondary to ARN progresses despite antiviral treatment. High-dose systemic corticosteroid therapy improves intraocular inflammation and improves vitreous opacity (Chang & Young 2007). However, some patients have CMO that is resistant or non-responsive to steroids. Bevacizumab is an anti-VEGF monoclonal antibody that blocks all VEGF isoforms. Intravitreal bevacizumab has been used successfully for the treatment of uveitic-resistant CMO (Cordero Coma et al. 2007) with short-term improvement in BCVA and decreased OCT retinal thickness in a considerable proportion of patients. However, VEGF-A is a survival factor for retinal neurons and a critical neuroprotectant during the adaptative response to ischaemic injury (Nishijima et al. 2007). Pegaptanib sodium is a selective RNA aptamer that inhibits VEGF-165, the VEGF isoform primarily responsible for pathological ocular neovascularization and vascular permeability, while sparing the physiological isoform VEGF-121. Retrospective data suggest that pegaptanib may provide therapeutic benefit for patients with diabetic macular oedema, proliferative diabetic retinopathy and retinal vein occlusion (Ng & Adamis 2006). In this case of uveitic CMO secondary to ARN, intravitreal injection of pegaptanib sodium was associated with improvement in BCVA and decreased retinal thickness. In conclusion, intravitreal injection of pegaptanib sodium can induce regression of CMO after ARN with resultant improvement of visual acuity. Treating more patients is necessary to understand whether the disappearance of CMO was coincidental or caused by pegaptanib sodium use. The long-term outcome is currently unknown. CMO recurrence is a possibility and may require additional therapy.