Publications by authors named "Eric Wakshull"

27 Publications

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Development of an anti-drug antibody assay to detect anti-drug antibodies to protein and PEG in a PEGylated molecule.

Bioanalysis 2020 Dec 12;12(23):1671-1679. Epub 2020 Nov 12.

Department of Bioanalytical Sciences, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA.

PEGylation technology is one of long-acting delivery (LAD) platforms used to increase half-life of protein therapeutics. However, PEGylation of anti-Factor D Fab (PEG-aFD) poses challenges for detecting anti-drug antibody (ADA) to both Fab and polyethylene glycol (PEG) portions. Although the bridging ELISA using traditional assay diluent containing Tween 20 is good for detecting ADA to Fab, it failed to detect ADA to PEG. Instead of only reducing Tween 20 in assay diluent, using a proprietary commercial buffer PEG50-1 as assay diluent successfully enabled the detection of ADA to both Fab and PEG with fit-for-purpose sensitivity and drug tolerance. Identification of appropriate assay diluent is critical for detection of ADA to both Fab and PEG in a PEGylated molecule.
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http://dx.doi.org/10.4155/bio-2020-0191DOI Listing
December 2020

Antibody-mediated activation of the FGFR1/Klothoβ complex corrects metabolic dysfunction and alters food preference in obese humans.

Proc Natl Acad Sci U S A 2020 11 2;117(46):28992-29000. Epub 2020 Nov 2.

Genentech Research and Early Development, Genentech, Inc., South San Francisco, CA 94080;

Fibroblast growth factor 21 (FGF21) controls metabolic organ homeostasis and eating/drinking behavior via FGF receptor 1/Klothoβ (FGFR1/KLB) complexes expressed in adipocytes, pancreatic acinar cells, and the nervous system in mice. Chronic administration of recombinant FGF21 or engineered variants improves metabolic health in rodents, nonhuman primates, and humans; however, the rapid turnover of these molecules limits therapeutic utility. Here we show that the bispecific anti-FGFR1/KLB agonist antibody BFKB8488A induced marked weight loss in obese cynomolgus monkeys while elevating serum adiponectin and the adipose expression of FGFR1 target genes, demonstrating its action as an FGF21 mimetic. In a randomized, placebo-controlled, single ascending-dose study in overweight/obese human participants, subcutaneous BFKB8488A injection caused transient body weight reduction, sustained improvement in cardiometabolic parameters, and a trend toward reduction in preference for sweet taste and carbohydrate intake. These data suggest that specific activation of the FGFR1/KLB complex in humans can be used as therapy for obesity-related metabolic defects.
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http://dx.doi.org/10.1073/pnas.2012073117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7682391PMC
November 2020

Immunoaffinity LC-MS/MS is more suitable than ELISA to quantify a PEGylated molecule in cynomolgus monkey serum.

Bioanalysis 2020 Aug 31;12(15):1061-1069. Epub 2020 Jul 31.

Department of Bioanalytical Sciences, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA.

Polyethylene glycolylation (PEGylation) technology is a long-acting delivery platform used to increase the half-life of protein therapeutics. Quantitation of PEGylated anti-Factor D Fab (PEG-aFD) poses bioanalytical challenges. An ELISA was developed to determine total Fab concentration in cynomolgus monkey serum following intravitreal administration of PEG-aFD. However, assay characterization showed a low recovery of about 25% for free unconjugated Fab whereas recovery for PEG-conjugated Fab was within 80-120%. To overcome this challenge, an immunoaffinity liquid chromatography tandem mass spectrometry (IA LC-MS/MS) assay was developed, achieving recovery within 80-120% for both free and conjugated Fab. Immunoaffinity LC-MS/MS is more suitable than ELISA to accurately quantify the total protein concentration of PEG-aFD in cynomolgus monkey serum.
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http://dx.doi.org/10.4155/bio-2020-0097DOI Listing
August 2020

Immunoaffinity LC-MS/MS to quantify a PEGylated anti-Factor D Fab biotherapeutic in cynomolgus monkey serum.

Bioanalysis 2019 Dec 8;11(23):2161-2173. Epub 2019 Nov 8.

Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA.

To develop a sensitive hybrid immunoaffinity LC-MS/MS monkey serum assay to quantify multiple components of anti-Factor D; a complex PEGylated Fab biotherapeutic explored as a therapy for age-related macular degeneration. Immunoaffinity enrichment of PEGylated anti-Factor D Fab, including fully conjugated, partially conjugated and unconjugated (i.e., free) Fab species, using a capture reagent coupled to magnetic beads was performed. The surrogate peptides derived from the therapeutic Fab via trypsin digestion were measured to obtain the total Fab concentrations. The method demonstrated the ability to accurately quantify both PEGylated and unconjugated Fab species. It was successfully validated with a LLOQ at 25.0 ng/ml.
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http://dx.doi.org/10.4155/bio-2019-0082DOI Listing
December 2019

Rapid Development of Glaucoma Via ITV Nonselective ANGPT 1/2 Antibody: A Potential Role for ANGPT/TIE2 Signaling in Primate Aqueous Humor Outflow.

Invest Ophthalmol Vis Sci 2019 10;60(13):4097-4108

Genentech Inc., South San Francisco, California, United States.

Purpose: Investigate a significant, dose-related increase in IOP, leading to glaucomatous damage to the neuroretina and optic nerve following intravitreal (ITV) administration of a bispecific F(ab')2 [anti-VEGF/Angiopoietins [ANGPT]F(ab')2] molecule in adult monkeys.

Methods: ITV ocular tolerability and investigation of anti-VEGF/ANGPT F(ab')2 (blocking both ANGPT1 and ANGPT2) was done in monkeys; mechanistic studies were done in neonatal mice.

Results: Following the second ITV dose of anti-VEGF/ANGPT F(ab')2, all 1.5- and 4-mg/eye treated monkeys developed elevated IOP, which eventually was associated with optic disc cupping and thinning of the neuroretinal rim. Histopathologic examination showed nonreversible axonal degeneration in the optic nerves of animals administered 1.5 mg/eye and higher that was considered secondary to high IOP. Anti-ANGPT Fab also caused elevated IOP in monkeys, but anti-VEGF Fab did not contribute to the IOP increase. In addition, an anti-ANGPT2-selective antibody did not change IOP. In mice simultaneous blockade of ANGPT1 and ANGPT2 impaired the expansion and formation of Schlemm's canal (SC) vessels, similar to genetic ablation of Angpt1/Angpt2 and their receptor TIE2. As previously reported, blocking ANGPT2 alone did not affect SC formation in mice.

Conclusions: Dual inhibition of ANGPT1/ANGPT2, but not ANGPT2 alone, leads to increased IOP and glaucomatous damage in monkeys. This confirms a role for TIE2/ANGPT signaling in the control of IOP in adults, a finding initially identified in transgenic mice. Dual pharmacologic inhibition of ANGPT1/ANGPT2 may affect aqueous drainage and homeostasis in adult monkeys and may be useful in developing novel models of glaucoma.
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http://dx.doi.org/10.1167/iovs.18-26349DOI Listing
October 2019

Bioanalytical challenges and unique considerations to support pharmacokinetic characterization of bispecific biotherapeutics.

Bioanalysis 2019 Mar 19;11(5):427-435. Epub 2019 Mar 19.

Genentech,1 DNA Way, South San Francisco, CA 94080, USA.

Compared with conventional (monospecific) therapeutics, bispecific protein therapeutics present unique challenges for pharmacokinetic (PK) characterization - namely, the characterization of multiple functional domains as well as the consideration of biotransformation or interference by the formation of antitherapeutic antibodies against each functional domain. PK characterization is essential to the success of the overall drug development plan and for molecules with multiple binding domains; multiple bioanalytical methods may be needed to answer critical questions for each phase of drug development. The number of bispecific protein therapeutics entering drug development continues to increase, and therefore, a bioanalytical strategy for the PK characterization of bispecific molecules and study of their in vivo structure-function relationship is needed. This review presents case studies and a regulatory perspective.
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http://dx.doi.org/10.4155/bio-2018-0146DOI Listing
March 2019

Comments on Assays Used to Measure VEGF in the Presence of Anti-VEGF Therapeutics.

Invest Ophthalmol Vis Sci 2018 08;59(10):4106

Genentech, Inc., South San Francisco, California, United States; and.

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http://dx.doi.org/10.1167/iovs.18-24792DOI Listing
August 2018

Phase I study of the anti-α5β1 monoclonal antibody MINT1526A with or without bevacizumab in patients with advanced solid tumors.

Cancer Chemother Pharmacol 2018 08 15;82(2):339-351. Epub 2018 Jun 15.

California Cancer Associates for Research & Excellence, Encinitas, CA, USA.

Purpose: MINT1526A is a monoclonal antibody that blocks the interaction of integrin alpha 5 beta 1 (α5β1) with its extracellular matrix ligands. This phase I study evaluated the safety and pharmacokinetics of MINT1526A with or without bevacizumab in patients with advanced solid tumors.

Methods: MINT1526A was administered every 3 weeks (Q3W) as monotherapy (arm 1) or in combination with bevacizumab 15 mg/kg, Q3W (arm 2). Each arm included a 3 + 3 dose-escalation stage and a dose-expansion stage.

Results: Twenty-four patients were enrolled in arm 1 (dose range 2-30 mg/kg) and 30 patients were enrolled in arm 2 (dose range 3-15 mg/kg). Monocyte α5β1 receptor occupancy was saturated at a dose of 15 mg/kg. No dose-limiting toxicities were observed, and the maximum tolerated dose was not reached in either arm. The most common adverse events, regardless of causality, included abdominal pain (25%), diarrhea (25%), nausea (21%), vomiting (21%), and fatigue (21%) in arm 1 and nausea (40%), fatigue (33%), vomiting (30%), dehydration (30%), headache (30%), and hypertension (30%) in arm 2. No grade ≥ 3 bleeding events were observed in either arm. No confirmed partial responses (PR) were observed in arm 1. In arm 2, one patient with thymic carcinoma experienced a confirmed PR and two patients with hepatocellular carcinoma (HCC) experienced durable minor radiographic responses.

Conclusions: MINT1526A, with or without bevacizumab, was well-tolerated. Preliminary evidence of combination efficacy, including in patients with HCC, was observed, but cannot be distinguished from bevacizumab monotherapy in this phase I study.
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http://dx.doi.org/10.1007/s00280-018-3622-8DOI Listing
August 2018

Development and validation of a novel semi-homogenous clinical assay for quantitation of Ranibizumab in human serum.

J Immunol Methods 2018 10 14;461:44-52. Epub 2018 May 14.

Department of BioAnalytical Sciences, Genentech, Inc., South San Francisco, CA, United States. Electronic address:

Ranibizumab (Lucentis®), a humanized antigen-binding fragment (Fab) monoclonal antibody that blocks VEGF-A activity, is currently approved for the treatment of several retinal degenerative diseases. The assessment of drug pharmacokinetics (PK) is essential for evaluating exposure as it relates to drug safety and efficacy. For drugs administered intravitreally, systemic drug levels during the course of clinical studies are typically 100 to 1000-fold lower than those of similar therapeutics dosed intravenously, posing a significant bioanalytical challenge for PK measurements. Thus, the development of a highly-sensitive assay for measuring pg/mL levels of ranibizumab in patients' sera after intravitreal administration was needed to support clinical studies. In this report, we describe the development of a novel method that utilizes a high-affinity murine monoclonal anti-ranibizumab-VEGF-complexes antibody (MARA) reagent to measure ranibizumab in human serum. The assay format utilizes a semi-homogeneous solution phase step using a monoclonal antibody (the MARA) that binds specifically to the ranibizumab-VEGF complex, but not to either alone. This unique reagent exhibited low non-specific binding and high selectivity, increasing signal-to-noise readouts and maximizing assay sensitivity. The resulting MARA enzyme-linked immunosorbent assay (ELISA) has a lower limit of quantification of 15 pg/mL in human serum. In the assay, serum samples are incubated overnight with a mixture containing biotinylated-VEGF and MARA, which form a three-molecule complex with ranibizumab in the sample. These complexes are then captured onto streptavidin-coated wells, followed by enzymatic detection using a horseradish peroxidase-labeled-anti-murine antibody reagent and a colorimetric reaction. The assay conditions were optimized to allow for quantitative detection of "total" ranibizumab levels in serum. The assay was fully validated, establishing its high tolerance to sample matrix, as well as its suitable specificity, accuracy, dilution linearity, as well as intra- and inter-assay precision. The MARA ELISA's novel and unique approach has resulted in a considerably more sensitive ranibizumab PK assay compared to earlier versions of this assay. The MARA ELISA has been used for PK measurements in multiple ranibizumab studies, supporting this drug's life-cycle management and related preclinical and clinical-development studies.
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http://dx.doi.org/10.1016/j.jim.2018.05.007DOI Listing
October 2018

Randomized Phase II Trial of Parsatuzumab (Anti-EGFL7) or Placebo in Combination with Carboplatin, Paclitaxel, and Bevacizumab for First-Line Nonsquamous Non-Small Cell Lung Cancer.

Oncologist 2018 06 7;23(6):654-e58. Epub 2018 Feb 7.

LungenClinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany

Lessons Learned: The lack of efficacy associated with anti-EGFL7 combined with standard bevacizumab and chemotherapy in this phase II trial in non-small cell lung carcinoma is consistent with the lack of benefit observed in colorectal carcinoma, highlighting the challenge of enhancing the efficacy of VEGF inhibition in unselected populations.Future efforts with agents like anti-EGFL7 should be guided by advances in pharmacodynamic and predictive biomarker development for antiangiogenic agents.

Background: Epidermal growth factor-like domain 7 (EGFL7) is an extracellular matrix-associated protein that is upregulated during angiogenesis and supports endothelial cell survival. This phase II trial evaluated the efficacy of the anti-EGFL7 antibody, parsatuzumab, in combination with bevacizumab plus platinum-based therapy for advanced or recurrent nonsquamous non-small cell lung cancer (NS-NSCLC).

Methods: Patients ( = 104) were randomized to either placebo or parsatuzumab (600 mg) in combination with bevacizumab (15 mg/kg) and carboplatin/paclitaxel, administered on day 1 of each 21-day cycle. Carboplatin and paclitaxel were administered for up to six cycles. Bevacizumab and parsatuzumab/placebo were administered for a maximum of 24 months.

Results: The progression-free survival (PFS) hazard ratio (HR) was 1.7 (95% confidence interval [CI], 1.0-2.8;  = .047). The median PFS was 6.7 months for the parsatuzumab arm versus 8.1 months for the placebo arm. The hazard ratio for overall survival (OS) was 1.1 (95% CI, 0.5-2.2;  = .847). The objective response rate (ORR) was 29% in the parsatuzumab arm and 56% in the placebo arm. Overall safety and tolerability were consistent with the established toxicity profile of bevacizumab.

Conclusion: There was no evidence of efficacy for the addition of parsatuzumab to the combination of bevacizumab and chemotherapy for first-line NS-NSCLC.
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http://dx.doi.org/10.1634/theoncologist.2017-0690DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6067939PMC
June 2018

Advancements in Understanding Immunogenicity of Biotherapeutics in the Intraocular Space.

AAPS J 2017 11 9;19(6):1656-1668. Epub 2017 Aug 9.

Nonclinical and Translational Sciences, Allergan, Irvine, California, USA.

Therapeutic breakthroughs in a number of retinal degenerative diseases have come about through the development of biotherapeutics administered directly into the eye. As a consequence of their use, we have gained more insight into the immune privileged status of the eye and the various considerations that development, manufacturing, and use of these drugs require. It has been observed that therapeutic proteins injected into the vitreous can elicit an immune response resulting in the production of anti-drug antibodies (ADAs) which can have clinical consequences. This review includes discussion of the anatomy, physiology, and specific area of the eye that are targeted for drug administration. The various immunologic mechanisms involved in the immune responses to intraocularly administered protein are discussed. This review entails discussion on chemistry, manufacturing, and control (CMC) and formulation-related issues that may influence the risk of immunogenicity. Based on the available immunogenicity profile of the marketed intraocular drugs and their reported adverse events, the animal models and the translational gap from animals to human are discussed. Thus, the objective of this review article is to assess the factors that influence immunogenicity in relation to intraocular administration and the steps taken for mitigating immunogenicity risks.
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http://dx.doi.org/10.1208/s12248-017-0128-yDOI Listing
November 2017

Randomized Phase II Trial of Parsatuzumab (Anti-EGFL7) or Placebo in Combination with FOLFOX and Bevacizumab for First-Line Metastatic Colorectal Cancer.

Oncologist 2017 04 8;22(4):375-e30. Epub 2017 Mar 8.

Duke Clinical Research Institute, Durham, North Carolina, USA

Lessons Learned: These negative phase II results for parsatuzumab highlight the challenges of developing an agent intended to enhance the efficacy of vascular endothelial growth factor inhibition without the benefit of validated pharmacodynamic biomarkers or strong predictive biomarker hypotheses.Any further clinical development of anti-EGFL7 is likely to require new mechanistic insights and biomarker development for antiangiogenic agents.

Background: EGFL7 (epidermal growth factor-like domain 7) is a tumor-enriched vascular extracellular matrix protein that supports endothelial cell survival. This phase II trial evaluated the efficacy of parsatuzumab (also known as MEGF0444A), a humanized anti-EGFL7 IgG monoclonal antibody, in combination with modified FOLFOX6 (mFOLFOX6) (folinic acid, 5-fluorouracil, and oxaliplatin) bevacizumab in patients with previously untreated metastatic colorectal cancer (mCRC).

Methods: One-hundred twenty-seven patients were randomly assigned to parsatuzumab, 400 mg, or placebo, in combination with mFOLFOX6 plus bevacizumab, 5 mg/kg. Treatment cycles were repeated every 2 weeks until disease progression or unacceptable toxicity for a maximum of 24 months, with the exception of oxaliplatin, which was administered for up to 8 cycles.

Results: The progression-free survival (PFS) hazard ratio was 1.17 (95% confidence interval [CI], 0.71-1.93;  = .548). The median PFS was 12 months for the experimental arm versus 11.9 months for the control arm. The hazard ratio for overall survival was 0.97 (95% CI, 0.46-2.1;  = .943). The overall response rate was 59% in the parsatuzumab arm and 64% in the placebo arm. The adverse event profile was similar in both arms.

Conclusions: There was no evidence of efficacy for the addition of parsatuzumab to the combination of bevacizumab and chemotherapy for first-line mCRC. 2017;22:375-e30.
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http://dx.doi.org/10.1634/theoncologist.2016-0133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5388369PMC
April 2017

Fit-for-purpose biomarker immunoassay qualification and validation: three case studies.

Bioanalysis 2016 Nov 7;8(22):2329-2340. Epub 2016 Oct 7.

Genentech, 1 DNA Way, South San Francisco, CA 94080, USA.

Aim: To improve on the efficiency of biomarker assay readiness, and for reliable biomarker data to support three drug programs, we implemented a fit-for-purpose approach, qualifying two biomarker assays and validating a third. Results/methodology: The qualification strategy and selection of experiments for two exploratory biomarkers (CXCL1, CCL19) was determined by the intended use of the biomarker data. The third biomarker, IL-6, was validated as the data would be used in monitoring patient safety during dose-escalation studies in a Phase I trial. All three assays passed a priori acceptance criteria.

Conclusion: These assays highlight strategies and methodologies for a fit-for-purpose approach. Minimum qualification, full qualification and validation were chosen and supported programs at different stages of drug development.
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http://dx.doi.org/10.4155/bio-2016-0184DOI Listing
November 2016

Preexisting Antibodies to an F(ab')2 Antibody Therapeutic and Novel Method for Immunogenicity Assessment.

J Immunol Res 2016 16;2016:2921758. Epub 2016 Jun 16.

BioAnalytical Sciences Department, Genentech, 1 DNA Way, South San Francisco, CA 94080, USA.

Anti-therapeutic antibodies (ATAs) may impact drug exposure and activity and induce immune complex mediated toxicity; therefore the accurate measurement of ATA is important for the analysis of drug safety and efficacy. Preexisting ATAs to the hinge region of anti-Delta like ligand 4 (anti-DLL4) F(ab')2, a potential antitumor therapeutic, were detected in cynomolgus monkey serum, which presented a challenge in developing assays for detecting treatment induced ATA. A total ATA assay was developed using a bridging ELISA that detected both anti-CDR and anti-framework ATA including anti-hinge reactivity. A competition assay that could detect 500 ng/mL of anti-CDR ATA in the presence of preexisting ATA was also developed to determine ATA specific to the anti-DLL4 F(ab')2 CDR using anti-DLL4 F(ab')2 and a control F(ab')2. We used these assay methods in a cynomolgus monkey in vivo study to successfully evaluate total and anti-CDR ATA. The preexisting anti-hinge reactivity was also observed to a lesser extent in human serum, and a similar approach could be applied for specific immunogenicity assessment in clinical trials.
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http://dx.doi.org/10.1155/2016/2921758DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927981PMC
March 2017

Workshop Report: AAPS Workshop on Method Development, Validation, and Troubleshooting of Ligand-Binding Assays in the Regulated Environment.

AAPS J 2015 Jul 30;17(4):1019-24. Epub 2015 Apr 30.

MKelley Consulting LLC, West Chester, PA, USA.

A novel format was introduced at the recent AAPS NBC Workshop on Method Development, Validation and Troubleshooting in San Diego on 18th May 2014. The workshop format was initiated by Binodh De Silva; Marie Rock and Sherri Dudal joined the initiative to develop and chair the workshop. Questions were solicited by a variety of avenues, including a Linked-In Discussion Group. Once collated and clarified, the topics covered assay development, validation, and analysis of PK, Immunogenicity, and Biomarkers with an additional topic on alternative bioanalytical technologies. A panel of experts (workshop report co-authors) was assigned to each topic to bring forward thought-provoking aspects of each topic. The format of the workshop was developed to target the needs of bioanalytical scientists with intermediate to advanced experience in the field ranging to enable robust discussion and to delve deeper into the current bioanalytical hot topics. While the new format allowed for an interactive session with the topical discussion driven by the audience members, it did not foster equal discussion time for all of the proposed topics, especially Biomarkers and alternative LBA technologies.
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http://dx.doi.org/10.1208/s12248-015-9767-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476978PMC
July 2015

Comparison of binding characteristics and in vitro activities of three inhibitors of vascular endothelial growth factor A.

Mol Pharm 2014 Oct 16;11(10):3421-30. Epub 2014 Sep 16.

Genentech, Inc. , 1 DNA Way, MS 56-2A, South San Francisco, California 94080, United States.

The objectives of this study were to evaluate the relative binding and potencies of three inhibitors of vascular endothelial growth factor A (VEGF), used to treat neovascular age-related macular degeneration, and assess their relevance in the context of clinical outcome. Ranibizumab is a 48 kDa antigen binding fragment, which lacks a fragment crystallizable (Fc) region and is rapidly cleared from systemic circulation. Aflibercept, a 110 kDa fusion protein, and bevacizumab, a 150 kDa monoclonal antibody, each contain an Fc region. Binding affinities were determined using Biacore analysis. Competitive binding by sedimentation velocity analytical ultracentrifugation (SV-AUC) was used to support the binding affinities determined by Biacore of ranibizumab and aflibercept to VEGF. A bovine retinal microvascular endothelial cell (BREC) proliferation assay was used to measure potency. Biacore measurements were format dependent, especially for aflibercept, suggesting that biologically relevant, true affinities of recombinant VEGF (rhVEGF) and its inhibitors are yet to be determined. Despite this assay format dependency, ranibizumab appeared to be a very tight VEGF binder in all three formats. The results are also very comparable to those reported previously.1-3 At equivalent molar ratios, ranibizumab was able to displace aflibercept from preformed aflibercept/VEGF complexes in solution as assessed by SV-AUC, whereas aflibercept was not able to significantly displace ranibizumab from preformed ranibizumab/VEGF complexes. Ranibizumab, aflibercept, and bevacizumab showed dose-dependent inhibition of BREC proliferation induced by 6 ng/mL VEGF, with average IC50 values of 0.088 ± 0.032, 0.090 ± 0.009, and 0.500 ± 0.091 nM, respectively. Similar results were obtained with 3 ng/mL VEGF. In summary Biacore studies and SV-AUC solution studies show that aflibercept does not bind with higher affinity than ranibizumab to VEGF as recently reported,4 and both inhibitors appeared to be equipotent with respect to their ability to inhibit VEGF function.
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http://dx.doi.org/10.1021/mp500160vDOI Listing
October 2014

Recommendations for the characterization of immunogenicity response to multiple domain biotherapeutics.

J Immunol Methods 2014 Jun 24;408:1-12. Epub 2014 May 24.

Biogen Idec, United States.

Many biotherapeutics currently in development have complex mechanisms of action and contain more than one domain, each with a specific role or function. Examples include antibody-drug conjugates (ADC), PEGylated, fusion proteins and bi-specific antibodies. As with any biotherapeutic molecule, a multi-domain biotherapeutic (MDB) can elicit immune responses resulting in the production of specific anti-drug antibodies (ADA) when administered to patients. As it is beneficial to align industry standards for evaluating immunogenicity of MDBs, this paper highlights pertinent immunogenicity risk factors and describes steps involved in the design of a testing strategy to detect and characterize binding (non-neutralizing and neutralizing, NAb) ADAs. In a common tier based approach, samples identified as ADA screen positive are confirmed for the binding specificity of the antibodies to the drug molecule via a confirmatory assay. The confirmation of specificity is generally considered as a critical step of the tier based approach in overall ADA response evaluation. Further characterization of domain specificity of polyclonal anti-MDB ADA response may be required based on the analysis of molecule specific risk factors. A risk based approach in evaluating the presence of NAbs for MDB is discussed in this article. Analysis of domain-specific neutralizing antibody reactivity should be based on the risk assessment as well as the information learned during binding ADA evaluation. Situations where additional characterization of NAb specificity is possible and justified are discussed. Case studies demonstrating applicability of the risk factor based approach are presented. In general, the presence of a domain with high immunogenicity risk or presence of a domain with high endogenous protein homology may result in an overall high immunogenicity risk level for the entire MDB and can benefit from domain specificity characterization of immune response. For low immunogenicity risk MDBs, domain specificity characterization could be re-considered at later clinical phases based on the need to explain specific clinical observations. Inclusion of domain specificity characterization in early phase clinical studies for MDBs with limited clinical immunogenicity experience may be considered to help understand its value in later clinical development. It is beneficial and is recommended to have a well-defined plan for the characterization of ADA domain specificity and data analysis prior to the initiation of sample testing. Overall, best practices for immunogenicity evaluation of complex MDBs are discussed.
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http://dx.doi.org/10.1016/j.jim.2014.05.010DOI Listing
June 2014

T-cell dependent immunogenicity of protein therapeutics: Preclinical assessment and mitigation.

Clin Immunol 2013 Dec 25;149(3):534-55. Epub 2013 Sep 25.

Amgen, USA.

Protein therapeutics hold a prominent and rapidly expanding place among medicinal products. Purified blood products, recombinant cytokines, growth factors, enzyme replacement factors, monoclonal antibodies, fusion proteins, and chimeric fusion proteins are all examples of therapeutic proteins that have been developed in the past few decades and approved for use in the treatment of human disease. Despite early belief that the fully human nature of these proteins would represent a significant advantage, adverse effects associated with immune responses to some biologic therapies have become a topic of some concern. As a result, drug developers are devising strategies to assess immune responses to protein therapeutics during both the preclinical and the clinical phases of development. While there are many factors that contribute to protein immunogenicity, T cell- (thymus-) dependent (Td) responses appear to play a critical role in the development of antibody responses to biologic therapeutics. A range of methodologies to predict and measure Td immune responses to protein drugs has been developed. This review will focus on the Td contribution to immunogenicity, summarizing current approaches for the prediction and measurement of T cell-dependent immune responses to protein biologics, discussing the advantages and limitations of these technologies, and suggesting a practical approach for assessing and mitigating Td immunogenicity.
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http://dx.doi.org/10.1016/j.clim.2013.09.006DOI Listing
December 2013

Regarding confirmatory immunogenicity assays.

J Pharm Biomed Anal 2013 Oct 19;84:173-6. Epub 2013 Jun 19.

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http://dx.doi.org/10.1016/j.jpba.2013.06.001DOI Listing
October 2013

Generation and characterization of a unique reagent that recognizes a panel of recombinant human monoclonal antibody therapeutics in the presence of endogenous human IgG.

MAbs 2013 Jul-Aug;5(4):540-54. Epub 2013 Apr 29.

BioAnalytical Sciences, Genentech, South San Francisco, CA USA.

Pharmacokinetic (PK) and immunohistochemistry (IHC) assays are essential to the evaluation of the safety and efficacy of therapeutic monoclonal antibodies (mAb) during drug development. These methods require reagents with a high degree of specificity because low concentrations of therapeutic antibody need to be detected in samples containing high concentrations of endogenous human immunoglobulins. Current assay reagent generation practices are labor-intensive and time-consuming. Moreover, these practices are molecule-specific and so only support one assay for one program at a time. Here, we describe a strategy to generate a unique assay reagent, 10C4, that preferentially recognizes a panel of recombinant human mAbs over endogenous human immunoglobulins. This "panel-specific" feature enables the reagent to be used in PK and IHC assays for multiple structurally-related therapeutic mAbs. Characterization revealed that the 10C4 epitope is conformational, extensive and mainly composed of non-CDR residues. Most key contact residues were conserved among structurally-related therapeutic mAbs, but the combination of these residues exists at low prevalence in endogenous human immunoglobulins. Interestingly, an indirect contact residue on the heavy chain of the therapeutic appears to play a critical role in determining whether or not it can bind to 10C4, but has no affect on target binding. This may allow us to improve the binding of therapeutic mAbs to 10C4 for assay development in the future. Here, for the first time, we present a strategy to develop a panel-specific reagent that can expedite the development of multiple clinical assays for structurally-related therapeutic mAbs.
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http://dx.doi.org/10.4161/mabs.24822DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3906308PMC
January 2014

Proposal for a new protein therapeutic immunogenicity titer assay cutpoint.

Bioanalysis 2011 Dec;3(23):2627-36

Department of Bioanalytical Sciences, Genentech, South San Francisco, CA 94080, USA.

Background: Generally, immunogenicity assessment strategies follow this assay triage schema: screen→confirm→titer. Each requires the determination of a threshold value (cutpoint) for decision making. No guidance documents exist for the determination of a specific titration assay cutpoint. The default practice is to use the screening assay cutpoint, frequently leading to controls or samples not reaching this cutpoint. We propose a method for determination of a titration cutpoint based upon the variance of the negative-control sample.

Results: Positive-control samples that did not cross a screening cutpoint did cross the titer cutpoint, albeit generating slightly lower titer values.

Conclusion: Our approach is consistent with the statistical methods currently recommended for the screening and confirmatory assay cutpoints and is operationally simple and efficient.
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http://dx.doi.org/10.4155/bio.11.273DOI Listing
December 2011

Association of endogenous anti-interferon-α autoantibodies with decreased interferon-pathway and disease activity in patients with systemic lupus erythematosus.

Arthritis Rheum 2011 Aug;63(8):2407-15

Department of Bioanalytical Research and Development MS-38, Genentech, South San Francisco, California 94080, USA.

Objective: Numerous observations implicate interferon-α (IFNα) in the pathophysiology of systemic lupus erythematosus (SLE); however, the potential impact of endogenous anti-IFNα autoantibodies (AIAAs) on IFN-pathway and disease activity is unclear. The aim of this study was to characterize IFN-pathway activity and the serologic and clinical profiles of AIAA-positive patients with SLE.

Methods: Sera obtained from patients with SLE (n = 49), patients with rheumatoid arthritis (n = 25), and healthy control subjects (n = 25) were examined for the presence of AIAAs, using a biosensor immunoassay. Serum type I IFN bioactivity and the ability of AIAA-positive sera to neutralize IFNα activity were determined using U937 cells. Levels of IFN-regulated gene expression in peripheral blood were determined by microarray, and serum levels of BAFF, IFN-inducible chemokines, and other autoantibodies were measured using immunoassays.

Results: AIAAs were detected in 27% of the serum samples from patients with SLE, using a biosensor immunoassay. Unsupervised hierarchical clustering analysis identified 2 subgroups of patients, IFN(low) and IFN(high) , that differed in the levels of serum type I IFN bioactivity, IFN-regulated gene expression, BAFF, anti-ribosomal P, and anti-chromatin autoantibodies, and in AIAA status. The majority of AIAA-positive patients had significantly lower levels of serum type I IFN bioactivity, reduced downstream IFN-pathway activity, and lower disease activity compared with the IFN(high) patients. AIAA-positive sera were able to effectively neutralize type I IFN activity in vitro.

Conclusion: Patients with SLE commonly harbor AIAAs. AIAA-positive patients have lower levels of serum type I IFN bioactivity and evidence for reduced downstream IFN-pathway and disease activity. AIAAs may influence the clinical course in SLE by blunting the effects produced by IFNα.
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http://dx.doi.org/10.1002/art.30399DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4028124PMC
August 2011

Development of a novel homogenous electrochemiluminescence assay for quantitation of ranibizumab in human serum.

J Pharm Biomed Anal 2010 Sep 6;52(5):680-6. Epub 2010 Feb 6.

Department of BioAnalytical Research and Development, Genentech, Inc., South San Francisco, CA 94080, USA.

A solution-phase electrochemiluminescence assay (ECLA) was developed to quantify ranibizumab in serum from patients treated with this biotherapeutic for neovascular age-related macular degeneration. Ranibizumab, a recombinant humanized Fab ("fragment, antigen binding"), binds with high affinity and specificity to vascular endothelial growth factor A (VEGF-A), inhibiting its activity. Fab molecules contain the amino acid sequence that binds antigen and are composed of one constant and one variable domain from each heavy and light chain of the antibody. High assay sensitivity was required to enable pharmacokinetic (PK) evaluation of ranibizumab-dosed patients in clinical trials. Our assay's lower limit of quantitation is 300 pg/mL ranibizumab in neat serum, achieving a 67-fold improvement in sensitivity relative to a conventional ELISA-based PK method. In this assay, ruthenium-labeled affinity-purified rabbit anti-ranibizumab antibodies and biotinylated rhVEGF are added to serum samples. During overnight incubation, these two labeled molecules bind to ranibizumab, and the resulting immune complex is then captured by streptavidin-coated paramagnetic beads and analyzed for electrochemiluminescence. The ranibizumab PK ECLA has a reporting range of 300-24,000 pg/mL, based on accuracy and precision parameters. It showed high precision for both intra- and inter-assay analyses. Recovery of ranibizumab from 10 individual donors averaged between 100% and 119% of nominal concentration. There was no cross-reactivity observed in the assay to other recombinant humanized antibodies (whole molecules or monoclonal antibody fragments) or human IgG. To our knowledge, this report represents the first description of development and validation of an ECLA-based PK assay for a recombinant humanized Fab therapeutic agent.
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http://dx.doi.org/10.1016/j.jpba.2010.01.048DOI Listing
September 2010

Increased plasma concentrations of cytoskeletal and Ca2+-binding proteins and their peptides in psoriasis patients.

Clin Chem 2008 Nov 18;54(11):1805-14. Epub 2008 Sep 18.

Biogen Idec, Inc., Boston, MA, USA.

Background: The mechanisms underlying psoriatic pathogenesis are not fully understood and might be elucidated by identifying novel disease-related molecular markers, including autoantigens.

Methods: We used 2 proteomic methods to analyze plasma samples from 20 psoriasis patients and 20 matched healthy donors. The first method focused on evaluating changes in glycoprotein concentrations and the plasma proteome, and the second method assessed endogenous proteolytic activity by analyzing the low molecular weight component of plasma.

Results: The integrated proteomic and peptidomic analysis identified a number of proteins and their fragments present at different concentrations in the plasma of psoriasis patients and healthy donors. We used ELISA to independently verify the changes in the concentrations of several of these proteins. One intriguing finding, increased concentrations of cytoskeletal and actin-binding proteins and their peptides in psoriatic plasma, suggested disease-related cell leakage of these proteins and their increased proteolysis. Among the increased proteins and peptides were thymosin beta 4, talin 1, actin gamma, filamin, and profilin. Increased concentrations of Ca(2+)-binding proteins calgranulins A and B in psoriatic plasma were also observed, confirming previous reports, and appeared to be relevant to the increase of cytoskeletal components. Another notable change in psoriatic plasma was a striking decrease in fibrinogen fragments.

Conclusions: The identified increased concentrations of cytoskeletal proteins, their peptides, and calgranulins in psoriatic plasma, as well as the underlying altered protease activity, are proposed to be related to psoriasis pathogenesis.
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http://dx.doi.org/10.1373/clinchem.2008.103770DOI Listing
November 2008

Recommendations for the design, optimization, and qualification of cell-based assays used for the detection of neutralizing antibody responses elicited to biological therapeutics.

J Immunol Methods 2007 Apr 12;321(1-2):1-18. Epub 2007 Jan 12.

Clinical Immunology, Amgen Inc., Thousand Oaks, CA 91320, USA.

The administration of biological therapeutics can evoke some level of immune response to the drug product in the receiving subjects. An immune response comprised of neutralizing antibodies can lead to loss of efficacy or potentially more serious clinical sequelae. Therefore, it is important to monitor the immunogenicity of biological therapeutics throughout the drug product development cycle. Immunoassays are typically used to screen for the presence and development of anti-drug product antibodies. However, in-vitro cell-based assays prove extremely useful for the characterization of immunoassay-positive samples to determine if the detected antibodies have neutralizing properties. This document provides scientific recommendations based on the experience of the authors for the development of cell-based assays for the detection of neutralizing antibodies in non-clinical and clinical studies.
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http://dx.doi.org/10.1016/j.jim.2006.12.004DOI Listing
April 2007

Combination of abundant protein depletion and multi-lectin affinity chromatography (M-LAC) for plasma protein biomarker discovery.

J Proteome Res 2007 Feb;6(2):662-71

Biogen Idec Inc., Boston, MA 02142, USA.

We report on the development of a robust and relatively high-throughput method for in-depth proteomic analysis of human plasma suitable for biomarker discovery. The method consists of depletion of albumin and IgG and multi-lectin affinity chromatography (M-LAC), followed by nanoLC-MS/MS analysis of digested proteins and label-free comparative quantitation of proteins. The performance of the method is monitored by multiple quality control points to ensure reproducibility of the analysis. The method identifies proteins that are reported to be present in normal plasma at concentrations of 10-100 ng/mL and that may be of particular interest when studying a variety of disease conditions. Numerous tissue leakage proteins of potentially even lower concentrations are also identified. When the method was used in a study to identify potential biomarkers of psoriasis, the differential abundance of proteins present at low mug/mL level was quantitated and later verified by ELISA measurements.
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http://dx.doi.org/10.1021/pr060413kDOI Listing
February 2007