Antibodies For Cancer Therapy Research Articles

Molecular imaging supports the development of multispecific cancer antibodies.

Multispecific antibodies are engineered antibody derivatives that can bind to two or more distinct epitopes or antigens. Unlike mixtures of monospecific antibodies, the binding properties of multispecific antibodies enable two specific molecules to be physically linked, a characteristic with important applications in cancer therapy. The field of multispecific antibodies is highly dynamic and expanding rapidly; to date, 15 multispecific antibodies have been approved for clinical use, of which 11 were approved for oncological indications, and more than 100 new antibodies are currently in clinical development. Nevertheless, substantial challenges limit the applications of multispecific antibodies in cancer therapy, particularly inefficient targeting of solid tumours and substantial adverse effects. Both PET and single photon emission CT imaging can reveal the biodistribution and complex pharmacology of radiolabelled multispecific antibodies. This Review summarizes the insights obtained from preclinical and clinical molecular imaging studies of multispecific antibodies, focusing on their structural properties, such as molecular weight, shape, target specificity, affinity and avidity. The opportunities associated with use of molecular imaging studies to support the clinical development of multispecific antibody therapies are also highlighted.

Systematic mutational analysis reveals an essential role of N275 in IgE stability.

Therapeutic antibodies have predominantly been IgG-based. However, the ongoing clinical trial of MOv18 IgE has highlighted the potential of using IgE antibodies in cancer therapy. While extensive studies targeting IgG glycosylation resulted in a rational basis for the development of enhanced biotherapeutics, IgE glycosylation remains an area with limited analyses. Previous studies on the role of IgE glycosylation present conflicting data with one study emphasizing the importance of N275 and T277 residues for FcεRI binding whereas another asserts the nonsignificance of IgE glycosylation in receptor interaction. While existing literature underscores the significance of glycans at the N275 position for binding to FcεR1 receptor and initiation of anaphylaxis, the role of other IgE glycosylation sites in folding or receptor binding remains elusive. This study systematically investigates the functional significance of N-linked glycosylation sites in the heavy chain of IgE which validates the pivotal role of N275 residue in IgE secretion and stability. Replacement of this asparagine to non-amine group moieties does not affect IgE function in vitro, yet substitution with aspartic acid compromises antibody yield. The deglycosylated IgE variant exhibits superior efficacy, challenging the conventional importance of glycosylation for effector function. In summary, our study unveils an intricate relationship between N-glycosylation sites and the structural-functional dynamics of IgE antibodies. Furthermore, it offers novel insights into the IgE scaffold, paving the way for the development of more effective and stable IgE-based therapeutics.

Double hit — bispecific antibodies in cancer therapy

Double hit — bispecific antibodies in cancer therapy

Abstract 7174: Pharmacokinetics and immunogenicity of anti-PD-1 antibody in humanized FcRn mouse models compared to immunocompetent mouse models

Abstract Introduction: The development and use of therapeutic antibodies in cancer therapy has increased significantly in recent years, led by the success of approved immune checkpoint blockade antibodies targeting PD-1 and PD-L1 axis. However, obtaining more clinically relevant pharmacokinetics (PK), safety and efficacy data for antibodies is still challenging in preclinical phase. Humanized FcRn (hFcRn) transgenic mouse model has a more faithful catabolism compared to WT mice, providing more accurate and predictable PK data of innovative antibody-based therapeutics at discovery stage[1]. In this study, we sought to investigate pharmacokinetics and immunogenicity characteristics of anti-PD-1 antibody in hFcRn transgenic mice and provide guidance for its differentiation of prediction value for drug PK and safety by comparing to WT mice. Methods: Non-tumor bearing hFcRn mice and wild type C57BL/6 mice were divided into 2 groups, 5 mice were enrolled into each group. Mice were administered anti-PD-1(Nivolumab) at 10 mg/kg single dose after grouping by intravenous (IV) injection. Blood samples at 12 timepoints (15min, 6h, 1, 2, 4, 7, 10, 14, 21, 28, 35, 42 days) post-dosing were collected for PK and Anti-Drug Antibody (ADA) analysis by MSD and ELISA. Results: Nivolumab clearance in hFcRn mice followed a typical linear profile with rapid distribution phase and slow elimination phase (t1/2 = 350 to 400 h). While the PK profile in C57BL/6 mice displayed non-linear clearance and very short elimination phase (t1/2 = 45 to 50 h). This data demonstrated that hFcRn mice have better correlated half-life with human (Nivolumab single dose by IV with 10mg/kg, t1/2 = 595 h) [2]. ADA analysis revealed that it was produced starting from Day 10 in wild type C57BL/6 mice and the frequency of ADA induced by Nivolumab in wild type mice (2/5) was higher than hFcRn mice (0/5). The variation of Nivolumab level was correlated with ADA production in wild type mice. This suggested hFcRn shows lower immunogenicity than wild type mice for human IgG drug and can potentially improve negative effect of ADA interference on PK evaluation. Conclusion: The result of this study demonstrated that the PK data in hFcRn mouse model was more predictive of human PK profile compared to wild type C57BL/6 mice. This advances innovation in antibody-based therapeutics and translational applications, with improved PK, safety and efficacy evaluation for preclinical human IgG drug development in cancer therapy.

Monoclonal Antibodies in Cancer Therapy

In recent years, there have been significant advancements in cancer treatment, particularly with the use of Monoclonal Antibodies (mAbs). These targeted therapies have shown promise in managing different types of cancer with fewer side effects due to their high specificity. They have become a predominant category of newly developed drugs. Monoclonal antibodies offer diverse mechanisms of action and can directly target cancer cells while also boosting long-lasting anti-tumor immune responses. This versatility has led to the development of innovative cancer treatment strategies. The use of monoclonal antibody drugs has grown rapidly, with FDA approval for various diseases, including cancer, autoimmune disorders, metabolic conditions, and infectious diseases. As of December 2019, 79 therapeutic mAbs have been approved by the FDA, but there is still room for expansion in this field.

Bispecific antibodies in cancer therapy: Target selection and regulatory requirements.

In recent years, the development of bispecific antibodies (bsAbs) has been rapid, with many new structures and target combinations being created. The boom in bsAbs has led to the successive issuance of industry guidance for their development in the US and China. However, there is a high degree of similarity in target selection, which could affect the development of diversity in bsAbs. This review presents a classification of various bsAbs for cancer therapy based on structure and target selection and examines the advantages of bsAbs over monoclonal antibodies (mAbs). Through database research, we have identified the preferences of available bsAbs combinations, suggesting rational target selection options and warning of potential wastage of medical resources. We have also compared the US and Chinese guidelines for bsAbs in order to provide a reference for their development.

Size-advantage of monovalent nanobodies against the macrophage mannose receptor for deep tumor penetration and tumor-associated macrophage targeting.

Rationale: Nanobodies (Nbs) have emerged as an elegant alternative to the use of conventional monoclonal antibodies in cancer therapy, but a detailed microscopic insight into the in vivo pharmacokinetics of different Nb formats in tumor-bearers is lacking. This is especially relevant for the recognition and targeting of pro-tumoral tumor-associated macrophages (TAMs), which may be located in less penetrable tumor regions. Methods: We employed anti-Macrophage Mannose Receptor (MMR) Nbs, in a monovalent (m) or bivalent (biv) format, to assess in vivo TAM targeting. Intravital and confocal microscopy were used to analyse the blood clearance rate and targeting kinetics of anti-MMR Nbs in tumor tissue, healthy muscle tissue and liver. Fluorescence Molecular Tomography was applied to confirm anti-MMR Nb accumulation in the primary tumor and in metastatic lesions. Results: Intravital microscopy demonstrated significant differences in the blood clearance rate and macrophage targeting kinetics of (m) and (biv)anti-MMR Nbs, both in tumoral and extra-tumoral tissue. Importantly, (m)anti-MMR Nbs are superior in reaching tissue macrophages, an advantage that is especially prominent in tumor tissue. The administration of a molar excess of unlabelled (biv)anti-MMR Nbs increased the (m)anti-MMR Nb bioavailability and impacted on its macrophage targeting kinetics, preventing their accumulation in extra-tumoral tissue (especially in the liver) but only partially influencing their interaction with TAMs. Finally, anti-MMR Nb administration not only allowed the visualization of TAMs in primary tumors, but also at a distant metastatic site. Conclusions: These data describe, for the first time, a microscopic analysis of (m) and (biv)anti-MMR Nb pharmacokinetics in tumor and healthy tissues. The concepts proposed in this study provide important knowledge for the future use of Nbs as diagnostic and therapeutic agents, especially for the targeting of tumor-infiltrating immune cells.

Emerging Antibodies in Cancer Therapy

Since the first monoclonal antibody, Orthoclone OKT3, was approved in 1986 for the treatment of acute allograft rejection in renal transplant recipients, the number of antibody‐based therapies has increased remarkably, with more than 130 monoclonal antibodies being currently available. In particular, due to their robust binding affinity and high specificity, various monoclonal antibodies have achieved success as complementary antitumor drugs. Moreover, therapeutic potency can be improved by engineering Y‐shaped binding sites of the antibodies to simultaneously recognize two distinct antigens; such molecules are called bispecific antibodies and function as a bridge, with one site binding to a tumor‐specific antigen and the other to immune cells to activate host immune responses. In addition, the development of trispecific antibodies has led to further enhancement of therapeutic specificity and effects. Indeed, a variety of structurally engineered antibodies have proven effective in tumor therapy. This article provides insights into the clinical translation of emerging antibody constructs, firstly describing conventional T cell‐redirecting bispecific antibodies and subsequently discussing the application of bispecific and trispecific antibody constructs based on innate immune cell recruitment. Finally, bispecific antibodies against mutant p53 and KRAS that have been actively studied in cancer treatment are introduced.

Neutrophils as immune effector cells in antibody therapy in cancer.

Tumor-targeting monoclonal antibodies are available for a number of cancer cell types (over)expressing the corresponding tumor antigens. Such antibodies can limit tumor progression by different mechanisms, including direct growth inhibition and immune-mediated mechanisms, in particular complement-dependent cytotoxicity, antibody-dependent cellular phagocytosis, and antibody-dependent cellular cytotoxicity (ADCC). ADCC can be mediated by various types of immune cells, including neutrophils, the most abundant leukocyte in circulation. Neutrophils express a number of Fc receptors, including Fcγ- and Fcα-receptors, and can therefore kill tumor cells opsonized with either IgG or IgA antibodies. In recent years, important insights have been obtained with respect to the mechanism(s) by which neutrophils engage and kill antibody-opsonized cancer cells and these findings are reviewed here. In addition, we consider a number of additional ways in which neutrophils may affect cancer progression, in particular by regulating adaptive anti-cancer immunity.

An anti-CTLA-4 heavy chain–only antibody with enhanced Treg depletion shows excellent preclinical efficacy and safety profile

The value of anti-CTLA-4 antibodies in cancer therapy is well established. However, the broad application of currently available anti-CTLA-4 therapeutic antibodies is hampered by their narrow therapeutic index. It is therefore challenging and attractive to develop the next generation of anti-CTLA-4 therapeutics with improved safety and efficacy. To this end, we generated fully human heavy chain-only antibodies (HCAbs) against CTLA-4. The hIgG1 Fc domain of the top candidate, HCAb 4003-1, was further engineered to enhance its regulatory T (Treg) cell depletion effect and to decrease its half-life, resulting in HCAb 4003-2. We tested these HCAbs in invitro and invivo experiments in comparison with ipilimumab and other anti-CTLA4 antibodies. The results show that human HCAb 4003-2 binds human CTLA-4 with high affinity and potently blocks the binding of B7-1 (CD80) and B7-2 (CD86) to CTLA-4. The results also show efficient tumor penetration. HCAb 4003-2 exhibits enhanced antibody-dependent cellular cytotoxicity function, lower serum exposure, and more potent anti-tumor activity than ipilimumab in murine tumor models, which is partly driven by a substantial depletion of intratumoral Tregs. Importantly, the enhanced efficacy combined with the shorter serum half-life and less systemic drug exposure invivo potentially provides an improved therapeutic window in cynomolgus monkeys and preliminary clinical applications. With its augmented efficacy via Treg depletion and improved safety profile, HCAb 4003-2 is a promising candidate for the development of next generation anti-CTLA-4 therapy.

Targeting the CD47-SIRPα Innate Immune Checkpoint to Potentiate Antibody Therapy in Cancer by Neutrophils.

Simple SummaryImmunotherapy aims to engage various immune cells in the elimination of cancer cells. Neutrophils are the most abundant leukocytes in the circulation and have unique mechanisms by which they can kill cancer cells opsonized by antibodies. However, neutrophil effector functions are limited by the inhibitory receptor SIRPα, when it interacts with CD47. The CD47 protein is expressed on all cells in the body and acts as a ‘don’t eat me’ signal to prevent tissue damage. Cancer cells can express high levels of CD47 to circumvent tumor elimination. Thus, blocking the interaction between CD47 and SIRPα may enhance anti-tumor effects by neutrophils in the presence of tumor-targeting monoclonal antibodies. In this review, we discuss CD47-SIRPα as an innate immune checkpoint on neutrophils and explore the preliminary results of clinical trials using CD47-SIRPα blocking agents.In the past 25 years, a considerable number of therapeutic monoclonal antibodies (mAb) against a variety of tumor-associated antigens (TAA) have become available for the targeted treatment of hematologic and solid cancers. Such antibodies opsonize cancer cells and can trigger cytotoxic responses mediated by Fc-receptor expressing immune cells in the tumor microenvironment (TME). Although frequently ignored, neutrophils, which are abundantly present in the circulation and many cancers, have demonstrated to constitute bona fide effector cells for antibody-mediated tumor elimination in vivo. It has now also been established that neutrophils exert a unique mechanism of cytotoxicity towards antibody-opsonized tumor cells, known as trogoptosis, which involves Fc-receptor (FcR)-mediated trogocytosis of cancer cell plasma membrane leading to a lytic/necrotic type of cell death. However, neutrophils prominently express the myeloid inhibitory receptor SIRPα, which upon interaction with the ‘don’t eat me’ signal CD47 on cancer cells, limits cytotoxicity, forming a mechanism of resistance towards anti-cancer antibody therapeutics. In fact, tumor cells often overexpress CD47, thereby even more strongly restricting neutrophil-mediated tumor killing. Blocking the CD47-SIRPα interaction may therefore potentiate neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC) towards cancer cells, and various inhibitors of the CD47-SIRPα axis are now in clinical studies. Here, we review the role of neutrophils in antibody therapy in cancer and their regulation by the CD47-SIRPα innate immune checkpoint. Moreover, initial results of CD47-SIRPα blockade in clinical trials are discussed.

Abstract 6115: Development of functionally differentiating anti-CD73 antibodies for cancer therapy

Abstract Background: Although the discovery and development of first-generation of immune checkpoint inhibitors (towards PD1 and CTLA-4) was a major milestone for cancer therapy, current clinical response rates are still considered very limited. Combination treatments are predicted to improve on these current immunotherapies including the targeting of the adenosine pathway (CD39, CD73 or A2AR), which has shown a lot of promise in preclinical and early clinical studies. CD73 is an ecto-5′-nucleotidase which transforms adenosine monophosphate (AMP) to adenosine. Adenosine is a soluble immunosuppressive metabolite that can suppress natural killer cells and cytotoxic CD8+ T cells. Blockade of CD73-mediated conversion of AMP to adenosine may therefore recover anti-tumor immunity through preventing the enrichment of adenosine in the tumor microenvironment. Method: In this campaign, two humanized and Fc-silenced IgG antibodies were generated named 7002-01 and 7002-04. The target binding epitopes of these candidates were revealed by binning experiments through bio-layer interferometry. Cell binding experiments were tested on human and cynomolgus CD73 overexpression CHO cell lines by flow cytometry. Cellular CD73 enzyme inhibition experiments were tested using A375, MDA-MB-231, H2030 and BT549 tumor cell lines via the CellTiter-Glo method. Soluble CD73 enzymatic tests were carried out on patient sera or recombinant CD73 protein using a similar method. T cell proliferation assays were performed using PBMC. In vivo efficacy studies were tested in B-NDG B2M-KO mice that were injected subcutaneously with A375 tumor cells and human PBMC. Results: Two candidates, 7002-01 and 7002-04, were selected based on their functional activity, that recognize different non-overlapping binding epitopes on CD73. Both candidates selectively bind to and can inhibit the activities of both membrane-bound and soluble human CD73 to high levels and seem to maintain inhibition at high dose-ranges without a hook effect. Both candidates can potently rescue adenosine-mediated T cell regulation. Additionally, 7002-01 and 7002-04 have combination synergy or additive effects for CD73 inhibition on soluble CD73, tumor cell lines that express CD73, and PBMC. 7002-01 and 7002-04 have single-agent anti-tumor efficacy and combination synergy with anti-PD1 antibodies in mice. 7002-01 has a typical antibody-like PK profile when rhesus monkeys were administered with a single intravenous dose at 25 or 50 mg/kg. No drug-related toxicities have been observed in GLP toxicity studies with dosages at 50, 250, and 500 mg/kg (QW, 4 weeks). Conclusion: Highly differentiating anti-CD73 antibodies were discovered that show maximal inhibition of both membranous and soluble CD73 without hook effects at high concentrations. 7002-01 was chosen as the lead molecule for its better overall activity profile and should be entering clinical trials by early 2022. Citation Format: Zhenqing Zhang, Yunli Jia, Xiaoniu Miao, Weifeng Huang, Chao Wang, Zhijun Yuan, Wenchao Jiang, Zhiyuan Li, Liandi Chen, Andy Tsun. Development of functionally differentiating anti-CD73 antibodies for cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6115.

Abstract 5520: AK129, an anti-PD1/LAG-3 bi-specific antibody for cancer therapy

Abstract Background: AK129 is a bi-specific antibody acts by co-blocking two immune checkpoint molecules co-expressed on T cells, PD-1 and LAG-3. Signaling through PD-1/PD-L1 exerts major effects on cytokines production by T cells, inhibiting production of IFN-γ and IL-2. LAG-3 is a cell surface molecule expressed on effector T cells and Tregs, which plays a vital role in regulating T cell function to promote tumoral immune escape. LAG-3 and PD-1 mediate different signaling pathways, but they may act synergistically to cause effector T cell inactivation and exhaustion. AK129 is being investigated as a cancer immunotherapeutic agent. Methods: The antigen binding activity of AK129 to PD-1 and LAG-3 were measured by ELISA and FACS. In reporter gene assay, the bioactivities of AK129 to block the interaction of PD-1 with PD-L1 and to neutralize LAG-3-mediated activity were determined. The bioactivity of AK129 to enhance IL-2 and IFN-γ production in PBMCs via blockade of PD-1 and PD-L1/2 interaction were determined by using cellular assays. In in-vivo pharmacology studies, anti-tumor activity of AK129 was investigated in BALB/c-hPD1/hLAG3 mice bearing CT26.WT tumor model. Results: AK129 showed good antigen binding to PD-1 and LAG-3. AK129 potently inhibited the binding of LAG-3 to its ligand MHC-II, and the binding of PD-1 to its ligand PD-L1, thus blocking downstream immune suppression. At the individual target level, AK129 demonstrated a similar PD-1 blocking activity compared to penpulimab, and similar LAG-3 blocking activity compared to relatlimab. Importantly, at the whole cell level, the enhancement effect of AK129 is stronger than the combination of penpulimab and relatlimab, as evidenced by significantly higher level of IL-2 and IFN-γ secretion from PBMCs. AK129 showed favorable anti-tumor activity in BALB/c-hPD1/hLAG3 mice bearing CT26.WT tumor model, with tumor growth inhibition values reaching 99.27% and 89.48% in high dose (20 mg/kg) and low dose (4 mg/kg) group of AK129, respectively. Conclusion: AK129 is a dual checkpoint blocking bispecific antibody with design features similar to the PD-1/CTLA-4 bispecific antibody AK104, which demonstrated efficacy similar to PD-1 and CTLA-4 antibody combo and much improved safety profile. AK129 has demonstrated robust anti-tumor activity in both in vivo and in vitro pre-clinical studies, and with enhanced T cell activity compared to PD-1 and LAG-3 antibody combo. The efficacy and safety of AK129 await testing in the clinic. Citation Format: Zhaoliang Huang, Xinghua Pang, Tingting Zhong, Chunshan Jin, Na Chen, Dennis Xia, Peng Zhang, Max Wang, Michelle Xia, Baiyong Li. AK129, an anti-PD1/LAG-3 bi-specific antibody for cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5520.

Addressing the challenges of CRS in bispecific monoclonal antibody cancer therapy

The benefit/risk ratio of immuno-oncology (I–O) agents is crucial when considering treatment options for cancer patients. Highly potent and targeted oncology agents come with high hopes of patient benefit. The tradeoff that comes with greater potency is the potential for serious and life-threatening toxicity, such as cytokine release syndrome (CRS). It is incumbent upon physicians, drug developers, and all other stakeholders to ensure a benefit/risk profile for these drugs that optimizes the patient experience throughout their treatment journey, iterating on mitigation measures that work while continuing to explore interventions that might further reduce risk of CRS.

Spotlight on combination therapy development: strategic directions towards improving current I-O response rates

Dr Adil Daud is an expert in immunotherapy and has pioneered the development of novel immunotherapeutics and targeted therapies. His fellowship in medical oncology was at the Memorial Sloan Kettering Cancer Center and was a faculty member at the Moffitt Cancer Center in Tampa, Fl. He is currently Professor of Medicine and Dermatology at the University of California, San Francisco. He is the director of the Melanoma Program and melanoma clinical research at the Helen Diller Family Cancer Center at UCSF. He lead the development of IL-12 in melanoma and has developed novel technology to deliver it in vivo. He has played a major role in developing PD-1 antibodies in cancer therapy. Recently he has developed novel assays to determine immune responsiveness in vivo. These assays can determine the likelihood of response to immune therapy and provide novel insights into immune drug development. He has collaborated on numerous clinical and translational clinical trials that have yielded insights into the use of immunotherapy. A full list of publications is at https://profiles.ucsf.edu/adil.daud.

Clinical development of an anti-GPC-1 antibody for the treatment of cancer

Introduction Glypican-1 (GPC-1) is a heparan sulfated proteoglycan (HSPG) overexpressed in multiple cancers. Multiple studies indicate the prominence of this cancer biomarker with significant diagnostic and therapeutic potential. Recent advances in monoclonal antibody (mAb)-based biopharmaceuticals targeting GPC-1 show promise towards managing GPC-1-positive solid tumours clinically. Areas covered This review addresses GPC-1 targeting antibodies for cancer therapy, in pre-clinical and clinical development. Current and emerging development of different anti-GPC-1 antibody formats based on mechanism of action and application are also discussed. Expert opinion Clinical development of novel anti-GPC-1 antibody-based formats is still in its early days. Using the patented anti-GPC-1 Miltuximab® as a case study, we have made an attempt to illustrate a pathway for pre-clinical to clinical translation, which could be useful for newer GPC-1 targeting immunotherapy agents.

Towards personalized antibody cancer therapy: development of a microfluidic cell culture device for antibody selection.

Antibody therapy has been one of the most successful therapies for a wide range of diseases, including cancer. One way of expediting antibody therapy development is through phage display technology. Here, by screening thousands of randomly assembled peptide sequences, it is possible to identify potential therapeutic candidates. Conventional screening technologies do not accommodate perfusion through the system, as is the case of standard plate-based cultures. This leads to a poor translation of the experimental results obtained in vitro when moving to a more physiologically relevant setting, such as the case of preclinical animal models or clinical trials. Microfluidics is a technology that can improve screening efficacy by replicating more physiologically relevant conditions such as shear stress. In this work, a polydimethylsiloxane/polystyrene-based microfluidic system for a continuously perfused culture of cancer cells is reported. Human colorectal adenocarcinoma cells (HCT116) expressing CXCR4 were used as a cell target. Fluorescently labeled M13 phages anti-CXCR4 were used to study the efficiency of the microfluidic system as a tool to study the binding kinetics of the engineered bacteriophages. Using our microfluidic platform, we estimated a dissociation constant of 0.45 pM for the engineered phage. Additionally, a receptor internalization assay was developed using SDF-1α to verify phage specificity to the CXCR4 receptor. Upon receptor internalization there was a signal reduction, proving that the anti-CXCR4 fluorescently labelled M13 phages bound specifically to the CXCR4 receptor. The simplicity and ease of use of the microfluidic device design presented in this work can form the basis of a generic platform that facilitates the study and optimization of therapies based on interaction with biological entities such as mammalian cells.

Abstract 1864: FS222, a tetravalent bispecific antibody targeting CD137 and PD-L1, is designed for optimal CD137 interactions resulting in potent T cell activation without toxicity

Abstract Background: CD137 (4-1BB, TNFRSF9) is expressed on activated lymphocytes, and its clustering leads to agonism of the receptor resulting in lymphocyte proliferation and pro-inflammatory cytokine release. First-generation CD137 antibodies for cancer therapy were high affinity and enabled for FcγR engagement with either severe toxicity or weak activity limiting their therapeutic benefit. However, CD137 remains a promising target for bispecific antibodies designed to re-direct T cell activity to the tumor whilst limiting unwanted toxicities. We have rationally designed and developed a unique tetravalent bispecific antibody targeting CD137 and PD-L1 with reduced FcγR binding for safe and efficacious cancer therapy (Lakins MA et al. 2020). Methods: A CD137/PD-L1 bispecific mAb2 antibody (FS222) was generated by introducing a bivalent affinity-optimized CD137-binding Fcab into a human IgG1 bivalent PD-L1 mAb. LALA mutations were introduced to abrogate FcγR activity. To elucidate its mechanism of action, FS222's binding valency was assessed by chemically-crosslinked mass spectrometry mapping (XL/MS). Immune pharmacology models were also used to evaluate PD-L1 dependent FS222 agonism against variants with differing valency for each target. Results: FS222 was specifically designed to bind CD137 with moderate affinity, and without PD-L1-mediated crosslinking it does not cluster or activate the receptor on immune cells. When PD-L1 was bound by FS222, this lead to crosslinking and subsequent clustering and activation of CD137. This clustering was enabled by avid bivalent binding as demonstrated by tetravalent FS222 being biologically more active than variants with reduced valency. Moreover, XL/MS demonstrated all four binding sites were able to concurrently bind target antigens. FS222 was well tolerated in a GLP toxicity study up to the maximal dose (30mg/kg QW). It was pharmacologically active in peripheral blood and lymphoid tissues and had a predicted t½ of 286 hours in humans. A surrogate anti-mouse CD137/PD-L1 mAb2 significantly reduced tumor growth in a murine syngeneic model and this correlated with a significant survival benefit and T cell activation. Conclusions: FS222 was designed to be a potent anti-human CD137/PD-L1 tetravalent conditional agonist with a unique combination of high affinity PD-L1 binding and moderate monovalent affinity, and highly avid binding, to CD137 on activated T cells. A favorable safety profile and immunopharmacology was observed with FS222 in a primate GLP toxicity study. Tetravalent binding by FS222 was required for optimal activity in pharmacology studies. Preclinically, FS222 was well-tolerated with an effective mechanism of action. Citation Format: Matthew A. Lakins, Jose Munoz-Olaya, Christel Veyssier, Daniel Jones, Emma Goodman, Quincy Kaka, Jennifer Ofoedu, Robert Hughes, Daniel Gliddon, Michelle Morrow, Neil Brewis. FS222, a tetravalent bispecific antibody targeting CD137 and PD-L1, is designed for optimal CD137 interactions resulting in potent T cell activation without toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1864.

Hunting for better biomarkers of response: where is real progress being made in understanding why patients do and don’t respond to I-O therapeutics?

Adil DaudProfessor of Medicine and Dermatology, University of California; and Director of the Melanoma program, Helen Diller Family Cancer Center, UCSFDr Adil Daud is an expert in immunotherapy and has pioneered the development of novel immunotherapeutics and targeted therapies. His fellowship in medical oncology was at the Memorial Sloan Kettering Cancer Center and was a faculty member at the Moffitt Cancer Center in Tampa, Fl. He is currently Professor of Medicine and Dermatology at the University of California, San Francisco. He is the director of the Melanoma Program and melanoma clinical research at the Helen Diller Family Cancer Center at UCSF. He led the development of IL-12 in melanoma and has developed novel technology to deliver it in vivo. He has played a major role in developing PD-1 antibodies in cancer therapy. Recently he has developed novel assays to determine immune responsiveness in vivo. These assays can determine the likelihood of response to immune therapy and provide novel insights into immune drug development. He has collaborated on numerous clinical and translational clinical trials that have yielded insights into the use of immunotherapy.Steven FlingSenior Staff Scientist, Fred Hutchinson Cancer Research Center; and Lab Director, Central Immune Monitoring LabSteven Fling, PhD serves as Lab Director for Central Immune Monitoring Lab (CIML), overseeing correlative biomarker studies for the NCI funded CITN (Cancer Immunotherapy Trials Network) and the industry funded ION (Immune Oncology Network). CITN/ION conducts early-stage, multicenter IO clinical trials, with a focus on agents/combinations to potentiate effective immune responses. Dr. Fling has >24 years research experience in T cell immunobiology, cancer vaccine and immunotherapeutic discovery, including ~13 years managing immunology research labs and directorship of collaborative research networks and consortia. Previously Dr. Fling served as Project Director for the IAVI’s Neutralizing Antibody Consortium, an international consortium working to develop a vaccine for HIV and in 2009 established lab operations at IAVI’s Neutralizing Antibody Center at the Scripps Research Institute (La Jolla, CA). In biotech R&D, Dr. Fling worked on vaccines for cancer and infectious diseases including adjuvant development at Corixa Corp (Seattle, WA) and as an Investigator in the Adjuvant Group for GSK Biologicals.John RossiSenior Director, Department of Translational Medicine, KiteI joined Kite in 2015 after 13 years at Amgen. I am currently a Senior Director in the Department of Translational Medicine at Kite and lead all pharmacology activities related to the clinical development of Kite’s cell therapy pipeline. At Kite, I have built an effective translational team to support the clinical development of axicabtagene ciloleucel (Yescarta®) and KTE-X19 (Tecartus®). My team has contributed directly to the regulatory approval of these products through pharmacokinetic and pharmacodynamic evaluation. Among many achievements at Kite, I have represented the organization through external scientific presentations and collaborative manuscripts with leading academic researchers such as Steven Rosenberg and James Kochenderfer at the NCI. Accomplishments include the discovery of metrics to characterize CAR T based on functionality, novel biomarker knowledge of how CARs work in the clinic, mechanistic information on toxicities and insights into the biology of the TME, including immune checkpoints, and the role of IL-15 in the context of CAR T-cell function.Majid GhoddusiSenior Director, Clinical Biomarkers, Poseida TherapeuticsDr Ghoddusi has over 15 years of experience in some of the most challenging areas of oncology with focus on drug discovery and clinical development. Dr Ghoddusi has broad and overarching insights into unmet therapeutic areas with expertise in translational sciences and clinical biomarker development which allows him to provide unique perspective on how to propel therapeutic projects from discovery to approval. Trained as a translational pathologist he has held numerous positions at large pharmaceutical and small biotech companies including Novartis, Celgene and Juno Therapeutics. His current focus at Poseida Therapeutic is Gene and Cellular Therapy.

Hunting for better biomarkers of response: where is real progress being made in understanding why patients do and don’t respond to I-O therapeutics?

Adil DaudProfessor of Medicine and Dermatology, University of California; and Director of the Melanoma program, Helen Diller Family Cancer Center, UCSFDr Adil Daud is an expert in immunotherapy and has pioneered the development of novel immunotherapeutics and targeted therapies. His fellowship in medical oncology was at the Memorial Sloan Kettering Cancer Center and was a faculty member at the Moffitt Cancer Center in Tampa, Fl. He is currently Professor of Medicine and Dermatology at the University of California, San Francisco. He is the director of the Melanoma Program and melanoma clinical research at the Helen Diller Family Cancer Center at UCSF. He led the development of IL-12 in melanoma and has developed novel technology to deliver it in vivo. He has played a major role in developing PD-1 antibodies in cancer therapy. Recently he has developed novel assays to determine immune responsiveness in vivo. These assays can determine the likelihood of response to immune therapy and provide novel insights into immune drug development. He has collaborated on numerous clinical and translational clinical trials that have yielded insights into the use of immunotherapy.Steven FlingSenior Staff Scientist, Fred Hutchinson Cancer Research Center; and Lab Director, Central Immune Monitoring LabSteven Fling, PhD serves as Lab Director for Central Immune Monitoring Lab (CIML), overseeing correlative biomarker studies for the NCI funded CITN (Cancer Immunotherapy Trials Network) and the industry funded ION (Immune Oncology Network). CITN/ION conducts early-stage, multicenter IO clinical trials, with a focus on agents/combinations to potentiate effective immune responses. Dr. Fling has >24 years research experience in T cell immunobiology, cancer vaccine and immunotherapeutic discovery, including ~13 years managing immunology research labs and directorship of collaborative research networks and consortia. Previously Dr. Fling served as Project Director for the IAVI’s Neutralizing Antibody Consortium, an international consortium working to develop a vaccine for HIV and in 2009 established lab operations at IAVI’s Neutralizing Antibody Center at the Scripps Research Institute (La Jolla, CA). In biotech R&D, Dr. Fling worked on vaccines for cancer and infectious diseases including adjuvant development at Corixa Corp (Seattle, WA) and as an Investigator in the Adjuvant Group for GSK Biologicals.John RossiSenior Director, Department of Translational Medicine, KiteI joined Kite in 2015 after 13 years at Amgen. I am currently a Senior Director in the Department of Translational Medicine at Kite and lead all pharmacology activities related to the clinical development of Kite’s cell therapy pipeline. At Kite, I have built an effective translational team to support the clinical development of axicabtagene ciloleucel (Yescarta®) and KTE-X19 (Tecartus®). My team has contributed directly to the regulatory approval of these products through pharmacokinetic and pharmacodynamic evaluation. Among many achievements at Kite, I have represented the organization through external scientific presentations and collaborative manuscripts with leading academic researchers such as Steven Rosenberg and James Kochenderfer at the NCI. Accomplishments include the discovery of metrics to characterize CAR T based on functionality, novel biomarker knowledge of how CARs work in the clinic, mechanistic information on toxicities and insights into the biology of the TME, including immune checkpoints, and the role of IL-15 in the context of CAR T-cell function.Majid GhoddusiSenior Director, Clinical Biomarkers, Poseida TherapeuticsDr Ghoddusi has over 15 years of experience in some of the most challenging areas of oncology with focus on drug discovery and clinical development. Dr Ghoddusi has broad and overarching insights into unmet therapeutic areas with expertise in translational sciences and clinical biomarker development which allows him to provide unique perspective on how to propel therapeutic projects from discovery to approval. Trained as a translational pathologist he has held numerous positions at large pharmaceutical and small biotech companies including Novartis, Celgene and Juno Therapeutics. His current focus at Poseida Therapeutic is Gene and Cellular Therapy.