Intravitreal injection of ziv-aflibercept in the treatment of choroidal and retinal vascular diseases

Efficient Expression of Functionally Active Aflibercept with Designed N-glycans

Aflibercept is a therapeutic recombinant fusion protein comprising extracellular domains of human vascular endothelial growth factor receptors (VEGFRs) and IgG1-Fc. It is a highly glycosylated protein with five N-glycosylation sites that might impact it structurally and/or functionally. Aflibercept is produced in mammalian cells and exhibits large glycan heterogeneity, which hampers glycan-associated investigations. Here, we report the expression of aflibercept in a plant-based system with targeted N-glycosylation profiles. Nicotiana benthamiana-based glycoengineering resulted in the production of aflibercept variants carrying designed carbohydrates, namely, N-glycans with terminal GlcNAc and sialic acid residues, herein referred to as AFLIGnGn and AFLISia, respectively. Both variants were transiently expressed in unusually high amounts (2 g/kg fresh leaf material) in leaves and properly assembled to dimers. Mass spectrometric site-specific glycosylation analyses of purified aflibercept showed the presence of two to four glycoforms in a consistent manner. We also demonstrate incomplete occupancy of some glycosites. Both AFLIGnGn and AFLISia displayed similar binding potency to VEGF165, with a tendency of lower binding to variants with increased sialylation. Collectively, we show the expression of functionally active aflibercept in significant amounts with controlled glycosylation. The results provide the basis for further studies in order to generate optimized products in the best-case scenario.

The Biosimilar Paradox: How Anti-Vascular Endothelial Growth Factor Biosimilars Could Increase Patient and Overall Health Care Costs

PURPOSE

Anti-vascular endothelial growth factor (VEGF) medications for intraocular use are a major and increasing cost, and biosimilars may be a means of reducing the high cost of many biologic medications. However, a bevacizumab biosimilar, which is currently pending Food and Drug Administration (FDA) approval (bevacizumab-vikg), paradoxically may increase the cost burden of intravitreal anti-VEGF agents, because off-label repackaged drugs may no longer be allowed per the Drug Quality and Security Act (DQSA). We aimed to investigate the potential impact of biosimilars on costs in the United States.

DESIGN

Cost analysis of anti-VEGF medications.

PARTICIPANTS

Medicare data from October 2022 and previously published market share data from 2019.

METHODS

Average sales prices (ASPs) of ranibizumab, aflibercept, and bevacizumab were calculated from Medicare allowable payments. The ASPs of biosimilars were calculated from wholesale acquisition costs from a representative distributor. The cost of an intraocular bevacizumab formulation is modeled at $500/1.25-mg dose and $900/1.25-mg dose.

MAIN OUTCOME MEASURES

Costs of anti-VEGF drugs to Medicare Part B and patients.

RESULTS

If an intraocular bevacizumab biosimilar were to be priced at $500, costs to Medicare would increase by $457 million from $3.01 billion to $3.47 billion (15.2% increase). Patient responsibility would increase by $117 million from $768 million to $884 million. Similarly, if intraocular bevacizumab were priced at $900, Medicare costs would increase by $897 million to $3.91 billion (29.8% increase), and patient responsibility would increase by $229 million to $997 million. If bevacizumab were $500/dose, switching all patients currently receiving ranibizumab or aflibercept to respective biosimilars would compensate for only 28.8% of the increased cost. Current prices of ranibizumab and aflibercept biosimilars would have to decrease by an aggregate of 15.7% to $616.80/injection, $1027.97/injection, and $1436.88/injection for ranibizumab 0.3 mg, ranibizumab 0.5 mg, and aflibercept, respectively.

CONCLUSIONS

An FDA-approved bevacizumab biosimilar for ophthalmic use could increase costs to the health care system and patients, raising concerns for access. This increase would not be offset by ranibizumab and aflibercept biosimilar use at current prices. These data support the need for an exemption of section 503B of the DQSA and continued use of repackaged off-label bevacizumab.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Ziv-aflibercept in Diabetic Macular Edema: Relation of Subfoveal Choroidal Thickness with Visual and Anatomical Outcomes

Purpose

To evaluate the effects of intravitreal ziv-aflibercept injections (IVZ) on subfoveal choroidal thickness (SCT) as well as on central macular thickness (CMT) and on best corrected visual acuity (BCVA) changes in eyes with center-involved diabetic macular edema (CI-DME).

Methods

Fifty-seven eyes of 36 patients with CI-DME were included in this prospective interventional case series. Structural optical coherence tomography (OCT) and enhanced depth imaging OCT were performed at baseline followed by three monthly 1.25 mg IVZ injections. Changes of SCT, CMT, and BCVA at each follow-up session were assessed. The association between baseline SCT and its monthly changes with final visual and anatomical outcomes were also assessed.

Results

CMT at baseline, and at the first, second, and third month follow-up sessions were 396 ± 119, 344 ± 115, 305 ± 89, and 296 ± 101 μm, respectively (P-value < 0.001). SCT at baseline, and at months one, two, and three were 236 ± 47, 245 ± 56, 254 ± 54, and 241 ± 54 μm, respectively (P-value > 0.99). Corresponding figures for BCVA were 0.58 ± 0.29, 0.47 ± 0.31, 0.4 ± 0.24, and 0.37 ± 0.23 LogMAR, respectively (P-value < 0.001). There was a statistically significant positive correlation between BCVA and CMT changes following IVZ injections (P-value < 0.001). However, there were no significant correlations between SCT changes and visual acuity (VA) and CMT changes following IVZ injections.

Conclusion

IVZ improved visual outcomes and macular thickness profiles in patients with CI-DME. However, IVZ had no significant effect on SCT. Baseline SCT and its monthly changes had no association with visual and anatomical outcomes.

Ziv-aflibercept: A cost-effective, off-label, highly potent antagonist of vascular endothelial growth factor

Ziv-aflibercept (Zaltrap^® ), a recombinant fusion protein that binds diffusible vascular endothelial growth factor (VEGF), is approved for the treatment of metastatic colorectal carcinoma. Its molecular structure is the same as aflibercept (Eylea^® ), thus making it an attractive option for the off-label treatment of chorioretinal vascular conditions. Ziv-aflibercept is distributed in 4 and 8 ml vials for intravenous use, and its cost after compounding is similar to bevacizumab. Studies with retinal pigment epithelium cytotoxicity, animal histologic sections and electroretinography have demonstrated its safety, and mathematical modelling combined with over four dozen clinical publications from different ophthalmic centres throughout the world attest to its efficacy. No appreciable differences in visual or anatomic outcomes between 1.25 mg (0.05 ml) and 2.5 mg (1.0 ml) doses have been noted. The long duration of action combined with the low cost make ziv-aflibercept an attractive anti-VEGF treatment option, especially in low- and middle-income countries where its popularity is increasing.