Composite Human Antibodies™Abzena has developed Composite Human Antibody™ technology to create fully-humanised antibodies that retain the binding a� nity and speci� city of the starting monoclonal antibody and are also devoid of CD4+ T cell epitopes, thereby avoiding undesirable immunogenicity in patients.

Through careful selection of human sequence segments and the application of in silico tools, CD4+ T cell epitopes can be avoided to reduce the risk of immunogenicity. Composite Human Antibodies™ are screened against the test antigen to ensure that the a� nity and speci� city of the antibody is maintained.

Abzena’s technology has been used to deimmunise over 60 antibodies with 11 on-going clinical trials (table 2).

Composite Human Antibodies™Advanced antibody humanisation and deimmunisation

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Anti bodyAnti body TypeType Immunogenicity Immunogenicity

anti -TNFα (Remicade™) Chimeric 33-60

A33 Humanised ~35

B72.3 Humanised 75

anti -VEGFR Humanised 50

anti -CD52 (Campath™) Humanised 50

anti -TNFα (Humira™) Fully human 15

Composite Human Antibody™ technology combines previous humanisation and deimmunisation technologies to generate fully-humanised therapeutic antibodies devoid of CD4+ T cell epitopes.

• Rational sequence design avoids CD4+ T cell epitopes, resulting in reduced immunogenicity compared to humanised and fully-human antibodies.

• Sequence changes combined with structural integrity assessment ensures excellent retention of a� nity and speci� city compared to the starting monoclonal antibody.

• Con� rmation of T cell epitope avoidance by Abzena’s EpiScreen™ technology.• Successfully applied to >60 antibodies with 8 antibodies in clinical development.• The Composite Human Antibody™ technology demonstrates superior capabilities to industry standard humanisation and

fully-human antibody technologies.

Humanisation alone isn’t enoughThe immunogenicity of therapeutic antibodies is a major problem in the clinic and the development of anti-therapeutic antibody responses in patients limits the e� cacy of these therapeutics. This problem has been signi� cantly reduced through the development of humanisation and fully-human antibody engineering technologies. Despite these improvements, clinical studies have shown that many humanised and fully-human antibodies are still immunogenic in patients, as shown in table 1.

Company Candidate Phase

Gilead GS-5745 II/III*

Opsona OPN-305 II*

Vascular Pharmaceuti cals VPI-2690B II

Gilead Simtuzumab (GS-6624) II*

NKT Therapeuti cs NKTT120 I

Adheron Therapeuti cs SDP 051 I

Therapure Innovati ons TBI 304H I

4 Undisclosed Undisclosed I

Table 2 (right): Composite Human Antibodies in clinical development. * clinical trials in multiple indications correct as of Mar 2016

Table 1 (above): Patients showing immunogenicity to biopharmaceuticals in clinical trials.

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Composite Human Antibodies™Advanced antibody humanisation and deimmunisation

Excellent a� nity was retainedStructural implication for every amino acid change is important in generating lead humanised antibodies. As a result, Composite Human Antibodies™ have excellent retention of a� nity and speci� city compared to the starting monoclonal antibody. Lead composite anti-CTLA4 variants were tested in a competition ELISA and showed good comparability with the starting antibody. Abzena have never failed to achieve an a� nity within two-fold of the stating antibody.

Immunogenicity was reducedIn order to assess the potential immunogenicity of the lead composite human antibody in comparison to the chimeric equivalent antibody, CD4+ T cell responses were measured using an EpiScreen™ ex vivo DC:T cell assay. After incubation of matured DC, preloaded with test antibodies, with autologous CD4+ T cells for seven days, the chimeric equivalent antibody and the lead induced signi� cant T cell responses in 16% and 4% of the donor cohort, respectively, the immunogenicity was reduced by the rational sequence design of the lead variant (by avoiding CD4+ T cell epitopes).

All Composite Human Antibodies™ produced are tested using EpiScreen™ technology to ensure that potential immunogenicity is minimised.

Partnering with AbzenaOur services are tailored for each project to ensure that the objectives are met or exceeded. Experienced project teams are assigned to each study focusing on progressing projects through to results in the minimum amount of time. Our clients uniformly judge us as professional and attentive partners who deliver quality results in a timely manner.

Left: Fig. 1. Characterisation of anti-CTLA-4 composite human antibody variants and the murine IgG. Antibodies were characterised by competition ELISA for binding to CTLA-4.

Case study: Composite Human anti-CTLA-4 antibodyCTLA-4 has been identi� ed as a target for treating unresectable metastatic melanomas. Targeting CTLA-4 reduces tumour related immune suppression. A murine antibody was generated that showed good binding to CTLA-4, and Composite Human Antibody™ technology was used to reduce its immunogenicity.

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Right: Fig. 2. CD4+ EpiScreen™ DC:T cell proliferation responses to the lead composite human antibody and chimeric equivalent. CD4+ T cells were incubated with autologous mature DC loaded with the samples and assessed for proliferation after 7 days incubation. T cell responses with an SI ≥1.90 (indicated by red dotted line) were considered positive.

Critical sequences identified Vh/Vl variant design Plasmid construction Transient cell line production Lead selection Manufacturing cell line production

Variant functionality analysis

Immunogenicity assessment

Project timelineProduction of a Composite Human Antibody takes ~20 weeks.

Critical sequences identified Vh/Vl variant design Plasmid construction Transient cell line production Lead selection Manufacturing cell line production

Variant functionality analysis

Immunogenicity assessment

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