Evaluation of potential retinal toxicity of adalimumab (Humira).
OBJECTIVE
The purpose of this study is to evaluate the retinal toxicity of two doses of adalimumab (Humira), a recombinant human IgG1 monoclonal antibody specific for human tumor necrosis factor (TNF), when injected intravitreally in rabbits.


METHODS
Sixteen male pigmented rabbits (divided into two groups, eight animals per group) were used for this study. Two concentrations of adalimumab were tested: 0.5 mg/0.1 ml and 5 mg/0.1 ml. Each concentration was injected intravitreally randomly in one eye (study group) of each rabbit (group I received 0.5 mg/0.1 ml and group II received 5.0 mg/0.1 ml), while in the other eye (control group) 0.1 ml of sterile balanced saline solution (BSS) was injected. Slit-lamp and funduscopic examinations were performed every second day for 2 weeks for signs of infection, inflammation and toxicity. A baseline electroretinogram (ERG) was performed before the experiment and at the last follow-up day (day 14). ERG examination followed ISCEV standards. At the last follow-up day, the animals were sacrificed and the enucleated eyes were prepared for histological evaluation of retinal toxicity.


RESULTS
No differences in ERG responses at photopic and scotopic conditions were observed in eyes injected with either concentration of adalimumab or BSS. Furthermore, histologic examination of the retina in the enucleated eyes (in all groups) did not demonstrate any evidence of drug toxicity.


CONCLUSIONS
Intravitreal adalimumab did not appear toxic to the retina in this experimental model at concentrations of 0.5 and 5 mg. If found safe in additional studies, intravitreally injected adalimumab could be evaluated for efficacy in the treatment of inflammatory eye conditions.
Tsilimbaris
Miltiadis
M
Institute of Vision and Optics (IVO), School of Health Sciences, University of Crete, 71003, Heraklion, Crete, Greece. tsilimb@med.uoc.gr
Diakonis
Vasilios F
VF
Naoumidi
Irini
I
Charisis
Spyridon
S
Kritikos
Iraklis
I
Chatzithanasis
George
G
Papadaki
Thekla
T
Plainis
Sotiris
S
D000068879:Adalimumab; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000633:toxicity*; D000911:Antibodies, Monoclonal / Q000633:toxicity*; D061067:Antibodies, Monoclonal, Humanized; D004596:Electroretinography / Q000187:drug effects; D007267:Injections; D008297:Male; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014822:Vitreous Body
D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D014409:Tumor Necrosis Factor-alpha; D000068879:Adalimumab