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Jakubiak P, Alvarez-Sánchez R, Fueth M, Broders O, Kettenberger H, Stubenrauch K, Caruso A. Ocular Pharmacokinetics of Intravitreally Injected Protein Therapeutics: Comparison among Standard-of-Care Formats. Mol Pharm 2021; 18:2208-2217. [PMID: 34014104 DOI: 10.1021/acs.molpharmaceut.0c01218] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The current standard of care for antivascular endothelial growth factor (VEGF) treatment requires frequent intravitreal (IVT) injections of protein therapeutics, as a result of limited retention within the eye. A thorough understanding of the determinants of ocular pharmacokinetics (PK) and its translation across species is an essential prerequisite for developing more durable treatments. In this work, we studied the ocular PK in macaques of the protein formats that comprise today's anti-VEGF standard of care. Cynomolgus monkeys received a single IVT injection of a single-chain variable fragment (scFv, brolucizumab), antigen-binding fragment (Fab, ranibizumab), fragment crystallizable-fusion protein (Fc-fusion, aflibercept), or immunoglobulin G monoclonal antibody (IgG, VA2 CrossMAb). Drug concentrations were determined in aqueous humor samples collected up to 42 days postinjection using immunoassay methods. The ocular half-life (t1/2) was 2.28, 2.62, 3.13, and 3.26 days for scFv, Fab, Fc-fusion, and IgG, respectively. A correlation with human t1/2 values from the literature confirmed the translational significance of the cynomolgus monkey as an animal model for ocular research. The relation between ocular t1/2 and molecular size was also investigated. Size was inferred from the molecular weight (MW) or determined experimentally by dynamic light scattering. The MW and hydrodynamic radius were found to be good predictors for the ocular t1/2 of globular proteins. The analysis showed that molecular size is a determinant of ocular disposition and may be used in lieu of dedicated PK studies in animals.
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Affiliation(s)
- Paulina Jakubiak
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Rubén Alvarez-Sánchez
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Matthias Fueth
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Olaf Broders
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Munich, F. Hoffmann-La Roche Ltd., Nonnenwald 2, D-82377 Penzberg, Germany
| | - Hubert Kettenberger
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, F. Hoffmann-La Roche Ltd., Nonnenwald 2, D-82377 Penzberg, Germany
| | - Kay Stubenrauch
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Munich, F. Hoffmann-La Roche Ltd., Nonnenwald 2, D-82377 Penzberg, Germany
| | - Antonello Caruso
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
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Baumgart Y, Otto A, Schäfer A, Usbeck E, Cott C, Schott A, Tornack M, Wenzel A, Mossie A, Birkenmeier G. Characterization of Novel Monoclonal Antibodies for Prostate-Specific Antigen (PSA) with Potency to Recognize PSA Bound to α2-Macroglobulin. Clin Chem 2005; 51:84-92. [PMID: 15528296 DOI: 10.1373/clinchem.2004.039636] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackground: Different molecular forms of prostate-specific antigen (PSA) have been used to differentiate between benign prostatic hyperplasia and prostate cancer. Detecting PSA bound to endogenous inhibitors such as α1-antichymotrypsin (ACT) and α2-macroglobulin (α2M) is often difficult because of epitope masking or sensitivity problems. Here we report the characterization of four novel mouse monoclonal antibodies (mabs) obtained by immunization with PSA-α2M complexes. Their ability to detect free PSA and PSA-inhibitor complexes was shown, and their epitopes were analyzed by phage display technology.Methods: The properties of the mabs were studied by competition and sandwich assays and by Western blotting. Epitope mapping was performed by screening of a phage display peptide library.Results: All four mabs recognized free PSA, PSA-ACT, and PSA-α2M complexes, but to various degrees. With different combinations of mabs in competition experiments, antibodies were identified that enhance binding of other mabs to PSA, forming the molecular basis of a very sensitive assay for the detection of PSA and PSA-ACT complexes. Mabs with highest reactivity for PSA-α2M were selected to establish an immunoassay for that complex. Western blot analysis revealed that all mabs recognized conformational epitopes of PSA. These findings were supported by phage display results demonstrating mimotopes in the PSA molecule.Conclusion: The results presented here could aid in the further development of clinically relevant assays for PSA and PSA-α2M complexes.
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Affiliation(s)
- Yvonne Baumgart
- Institute of Biochemistry, University of Leipzig, Liebigstrasse 16, 04103 Leipzig, Germany
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