Purchase this article with an account.
Wesley M Jackson, Livia Brier, Mavish Mahomed, Ricardo Lamy, Matilda F Chan; Multivalent Conjugation to Hyaluronic Acid Increases the Intravitreal Residence Time of Anti-VEGF Antibodies. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1905.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Anti-VEGF has emerged as an important treatment for diabetic macular edema. However, the frequency of administration creates a significant burden because to maintain visual acuity, intravitreal injections are required as frequently as monthly. We conjugated multiple copies (i.e., valency) of anti-VEGF antibodies with soluble hyaluronic acid (HyA) biopolymers and tested whether multivalent conjugation was sufficient to increase their intravitreal half-life.
We conjugated 25-45 anti-VEGF single-domain antibodies (VHH) to soluble HyA biopolymers (~800 kDa) using our previously published methods. We compared the ability of these conjugates to bind VEGF-A compared to the unconjugated antibody using an ELISA assay. To determine the effect of biopolymer conjugation on the transport properties of the conjugates, we measured their diffusion rates out of HyA-based hydrogels in vitro. Finally, we compared the intravitreal half-lives of multivalent VHH conjugates in vivo using a rat model. In this experiment, all of the VHH was tagged with a fluorescent reporter, and we used 4 independent conjugate batches. In each eye, we injected 5 μL of a 275 μg/mL solution of VHH either unconjugated or as multivalent conjugate. At various times after injection, we measured the concentration of VHH in the vitreous (n=6 per time point), and we fit the data to an exponential curve to determine the half-life of each treatment.
Multivalent conjugation did not have a significant effect on the IC50 values for the anti-VEGF conjugates (812 ± 181 nM) compared to the unconjugated antibody (758.3 ± 83 nM), but the conjugates exhibited significant reduction in their in vitro diffusion rate that was approximately 4-fold lower than the unconjugated antibody (p<0.001, t-test, n=3). We observed similar results in vivo, such that the intravitreal half-life of the multivalent anti-VEGF conjugate was approximately 8-fold higher than the unconjugated antibody.
Our preclinical models demonstrated that multivalent conjugation substantially increases the half-life of anti-VEGF antibodies following intravitreal injection without affecting their bioactivity. Thus, we anticipate that our antibody conjugates will provide effective treatment with substantially less frequent administration as we advance to preclinical efficacy models and clinical studies.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only