Development of Plant-Derived Bispecific Monoclonal Antibody Targeting PD-L1 and CTLA-4 against Mouse Colorectal Cancer.

Checkpoint blockade immunotherapy has revolutionized cancer treatment, with monoclonal antibodies targeting immune checkpoints, yielding promising clinical benefits. However, with the advent of resistance to immune checkpoint inhibitor treatment in clinical trials, developing next-generation antibodies with potentially increased efficacy is critical. Here, we aimed to generate a recombinant bispecific monoclonal antibody for dual inhibition of programmed cell death protein 1/programmed cell death ligand 1 and cytotoxic T-lymphocyte-associated protein 4 axes. The plant system was used as an alternative platform for bispecific monoclonal antibody production. Dual variable domain immunoglobulin atezolizumab × 2C8 is a plant-derived bispecific monoclonal antibody that combines both programmed cell death ligand 1 and cytotoxic T-lymphocyte-associated protein 4 blockade into a single molecule. Dual variable domain immunoglobulin atezolizumab × 2C8 was transiently expressed in Nicotiana benthamiana and the expression level was determined to be the highest after 4 days of infiltration. The size and assembly of the purified bispecific monoclonal antibody were determined, and its function was investigated in vitro and in vivo. The molecular structures of plant-produced dual variable domain immunoglobulin atezolizumab × 2C8 are as expected, and it was mostly present as a monomer. The plant-produced dual variable domain immunoglobulin atezolizumab × 2C8 showed in vitro binding to programmed cell death ligand 1 and cytotoxic T-lymphocyte-associated protein 4 proteins. The antitumor activity of plant-produced bispecific monoclonal antibody was tested in vivo by treating humanized Balb/c mice bearing a CT26 colorectal tumor. Plant-produced dual variable domain immunoglobulin atezolizumab × 2C8 significantly inhibited tumor growth by reducing tumor volume and weight. Body weight changes indicated that the plant-produced bispecific monoclonal antibody was safe and tolerable. Overall, this proof of concept study demonstrated the viability of plants to produce functional plant-based bispecific immunotherapy.

Real-World Efficacy and Safety of Amivantamab for EGFR-Mutant NSCLC.

INTRODUCTION: Amivantamab-vmjw (amivantamab) is a bispecific EGFR/MET antibody approved for patients with advanced NSCLC with EGFR exon 20 insertion mutations, after prior therapy. Nevertheless, the benefits and safety of amivantamab in other EGFR-mutant lung cancer, with or without osimertinib, and with concurrent radiation therapy, are less known. METHODS: We queried the MD Anderson Lung Cancer GEMINI, Fred Hutchinson Cancer Research Center, University of California Davis Comprehensive Cancer Center, and Stanford Cancer Center's database for patients with EGFR-mutant NSCLC treated with amivantamab, not on a clinical trial. The data analyzed included initial response, duration of treatment, and concomitant radiation safety in overall population and prespecified subgroups. RESULTS: A total of 61 patients received amivantamab. Median age was 65 (31-81) years old; 72.1% were female; and 77% were patients with never smoking history. Median number of prior lines of therapies was four. On the basis of tumor's EGFR mutation, 39 patients were in the classical mutation cohort, 15 patients in the exon 20 cohort, and seven patients in the atypical cohort. There were 37 patients (58.7%) who received amivantamab concomitantly with osimertinib and 25 patients (39.1%) who received concomitant radiation. Furthermore, 54 patients were assessable for response in the overall population; 19 patients (45.2%) had clinical response and disease control rate (DCR) was 64.3%. In the classical mutation cohort of the 33 assessable patients, 12 (36.4%) had clinical response and DCR was 48.5%. In the atypical mutation cohort, six of the seven patients (85.7%) had clinical response and DCR was 100%. Of the 13 assessable patients in the exon 20 cohort, five patients (35.7%) had clinical response and DCR was 64.3%. Adverse events reported with amivantamab use were similar as previously described in product labeling. No additional toxicities were noted when amivantamab was given with radiation with or without osimertinib. CONCLUSIONS: Our real-world multicenter analysis revealed that amivantamab is a potentially effective treatment option for patients with EGFR mutations outside of exon 20 insertion mutations. The combination of osimertinib with amivantamab is safe and feasible. Radiation therapy also seems safe when administered sequentially or concurrently with amivantamab.

Teclistamab impairs humoral immunity in patients with heavily pretreated myeloma: importance of immunoglobulin supplementation.

ABSTRACT: Teclistamab and other B-cell maturation antigen (BCMA)-targeting bispecific antibodies (BsAbs) have substantial activity in patients with heavily pretreated multiple myeloma (MM) but are associated with a high rate of infections. BCMA is also expressed on normal plasma cells and mature B cells, which are essential for the generation of a humoral immune response. The aim of this study was to improve the understanding of the impact of BCMA-targeting BsAbs on humoral immunity. The impact of teclistamab on polyclonal immunoglobulins and B cell counts was evaluated in patients with MM who received once-weekly teclistamab 1.5 mg/kg subcutaneously. Vaccination responses were assessed in a subset of patients. Teclistamabinduced rapid depletion of peripheral blood B cells in patients with MM and eliminated normal plasma cells in ex vivo assays. In addition, teclistamab reduced the levels of polyclonal immunoglobulins (immunoglobulin G [IgG], IgA, IgE, and IgM), without recovery over time while receiving teclistamab therapy. Furthermore, response to vaccines against Streptococcus pneumoniae, Haemophilus influenzae type B, and severe acute respiratory syndrome coronavirus 2 was severely impaired in patients treated with teclistamab compared with vaccination responses observed in patients with newly diagnosed MM or relapsed/refractory MM. Intravenous immunoglobulin (IVIG) use was associated with a significantly lower risk of serious infections among patients treated with teclistamab (cumulative incidence of infections at 6 months: 5.3% with IVIG vs 54.8% with observation only [P < .001]). In conclusion, our data show severe defects in humoral immunity induced by teclistamab, the impact of which can be mitigated by the use of immunoglobulin supplementation. This trial was registered at www.ClinicalTrials.gov as #NCT04557098.

Age, dose, and binding to TfR on blood cells influence brain delivery of a TfR-transported antibody.

BACKGROUND: Transferrin receptor 1 (TfR1) mediated brain delivery of antibodies could become important for increasing the efficacy of emerging immunotherapies in Alzheimer's disease (AD). However, age, dose, binding to TfR1 on blood cells, and pathology could influence the TfR1-mediated transcytosis of TfR1-binders across the blood-brain barrier (BBB). The aim of the study was, therefore, to investigate the impact of these factors on the brain delivery of a bispecific TfR1-transported Aß-antibody, mAb3D6-scFv8D3, in comparison with the conventional antibody mAb3D6. METHODS: Young (3-5 months) and aged (17-20 months) WT and tg-ArcSwe mice (AD model) were injected with 125I-labeled mAb3D6-scFv8D3 or mAb3D6. Three different doses were used in the study, 0.05 mg/kg (low dose), 1 mg/kg (high dose), and 10 mg/kg (therapeutic dose), with equimolar doses for mAb3D6. The dose-corrected antibody concentrations in whole blood, blood cells, plasma, spleen, and brain were evaluated at 2 h post-administration. Furthermore, isolated brains were studied by autoradiography, nuclear track emulsion, and capillary depletion to investigate the intrabrain distribution of the antibodies, while binding to blood cells was studied in vitro using blood isolated from young and aged mice. RESULTS: The aged WT and tg-ArcSwe mice showed significantly lower brain concentrations of TfR-binding [125I]mAb3D6-scFv8D3 and higher concentrations in the blood cell fraction compared to young mice. For [125I]mAb3D6, no significant differences in blood or brain delivery were observed between young and aged mice or between genotypes. A low dose of [125I]mAb3D6-scFv8D3 was associated with increased relative parenchymal delivery, as well as increased blood cell distribution. Brain concentrations and relative parenchymal distribution of [125I]mAb3D6-scFv8D6 did not differ between tg-ArcSwe and WT mice at this early time point but were considerably increased compared to those observed for [125I]mAb3D6. CONCLUSION: Age-dependent differences in blood and brain concentrations were observed for the bispecific antibody mAb3D6-scFv8D3 but not for the conventional Aß antibody mAb3D6, indicating an age-related effect on TfR1-mediated brain delivery. The lowest dose of [125I]mAb3D6-scFv8D3 was associated with higher relative BBB penetration but, at the same time, a higher distribution to blood cells. Overall, Aß-pathology did not influence the early brain distribution of the bispecific antibody. In summary, age and bispecific antibody dose were important factors determining brain delivery, while genotype was not.

Anti-CD19 monoclonal antibodies for the treatment of relapsed or refractory B-cell malignancies: a narrative review with focus on diffuse large B-cell lymphoma.

PURPOSE: CD19 is a cell surface protein that is found on both healthy and malignant B cells. Accordingly, it has become an important target for novel treatments for non-Hodgkin lymphomas and B-cell leukaemia. Three anti-CD19 monoclonal antibodies with distinct mechanisms of action have been developed for the treatment of B-cell malignancies. METHODS: We reviewed the preclinical and clinical data on the development of the newly approved anti-CD19 monoclonal antibodies blinatumomab, tafasitamab and loncastuximab tesirine, and consider their place in the treatment of relapsed or refractory B-cell malignancies. RESULTS: Blinatumomab is a bispecific T-cell engager that binds to both CD19 on B cells and CD3 on T cells, facilitating antibody-dependent cytotoxicity. Blinatumomab significantly prolongs overall survival in patients with relapsed or refractory B-cell acute lymphoblastic leukaemia, although cytokine release syndrome and severe neurotoxicity may necessitate discontinuation. Tafasitamab, which has modified anti-CD19 Fab and Fc regions, has significantly enhanced affinity for both CD19 and effector cell receptors compared with unmodified anti-CD19. In L-MIND, tafasitamab plus lenalidomide provided an overall response rate (ORR) of 57.5% in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) in patients non-transplant eligible. Loncastuximab tesirine is an antibody-drug conjugate that has been studied as monotherapy and in combination with ibrutinib in 3L + relapsed or refractory DLBCL. The ORR was 48.3% in a phase II trial of loncastuximab tesirine. The optimal place of anti-CD19 monoclonal antibodies in therapy has yet to be determined, but the prospect of improved outcomes for at least some patients with treatment-resistant B-cell malignancies appears likely, particularly in those with limited therapeutic options and poor prognosis.

Preclinical development of a bispecific TNFα/IL-23 neutralising domain antibody as a novel oral treatment for inflammatory bowel disease.

Anti-TNFα and anti-IL-23 antibodies are highly effective therapies for Crohn's disease or ulcerative colitis in a proportion of patients. V56B2 is a novel bispecific domain antibody in which a llama-derived IL-23p19-specific domain antibody, humanised and engineered for intestinal protease resistance, V900, was combined with a previously-described TNFα-specific domain antibody, V565. V56B2 contains a central protease-labile linker to create a single molecule for oral administration. Incubation of V56B2 with trypsin or human faecal supernatant resulted in a complete separation of the V565 and V900 monomers without loss of neutralising potency. Following oral administration of V900 and V565 in mice, high levels of each domain antibody were detected in the faeces, demonstrating stability in the intestinal milieu. In ex vivo cultures of colonic biopsies from IBD patients, treatment with V565 or V900 inhibited tissue phosphoprotein levels and with a combination of the two, inhibition was even greater. These results support further development of V56B2 as an oral therapy for IBD with improved safety and efficacy in a greater proportion of patients as well as greater convenience for patients compared with traditional monoclonal antibody therapies.

Real-world experience on the tolerability and safety of emicizumab prophylaxis in paediatric patients with severe haemophilia A with and without FVIII inhibitors.

BACKGROUND: Emicizumab is a bispecific monoclonal antibody that bridges activated factor (F) IX and FX, and maintains haemostasis in patients with haemophilia A (PwHA). As a novel agent, many questions remain unanswered about the loss of emicizumab efficacy due to anti-drug antibody (ADA) development, the incidence of inhibitor recurrence in previously tolerized patients, and the risk of de novo inhibitor development. AIM: To present real-world experience regarding tolerability, side effects, and outcomes of adverse events of emicizumab prophylaxis in paediatric PwHA. METHODS: Data on tolerability, compliance, adverse events, and laboratory results of paediatric patients receiving emicizumab prophylaxis, treated at the Haemophilia Comprehensive Care Centre, at Birmingham Children's Hospital between March 2018 and June 2021, were collected. RESULTS: Our results showed that out of 52 patients, four experienced minor adverse events, two developed headaches, one developed abdominal pain and nausea, and one developed injection site reactions. Moreover, four patients experienced major adverse events, including severe headaches, major bleeding events, development of ADAs, and recurrence of inhibitors. Emicizumab prophylaxis was discontinued in three patients (5.7% of the cohort) due to adverse events. In addition, emicizumab was discontinued in one patient because of poor compliance. No adverse events were reported in previously untreated/minimally treated patients, represented by four patients in our cohort. CONCLUSIONS: The real-world experience of emicizumab prophylaxis in our cohort showed that emicizumab was safe and well tolerated in paediatric PwHA with and without inhibitors. Long-term assessment is crucial to monitor major adverse events, recurrence of inhibitors, and development of ADAs.

Loss of CD22 expression and expansion of a CD22dim subpopulation in adults with relapsed/refractory B-lymphoblastic leukaemia after treatment with Inotuzumab-Ozogamicin.

Treatment options for relapsed or refractory B-lymphoblastic leukaemia (r/r B-ALL) are limited and the prognosis of these patients remains dismal, but novel immunotherapeutic options such as the anti-CD22 antibody-drug-conjugate Inotuzumab-Ozogamicin (InO) have improved outcomes in these patients. Flow cytometry is essential to assess antigen-expression prior to treatment initiation of antigen-directed immunotherapies. Here, we present flow cytometric and clinical data of three adult patients with r/r B-ALL who failed treatment with InO associated with reduced or lost antigen-expression. In addition, we present comparative data on two different diagnostic CD22-specific antibody clones that exhibit significant differences in staining intensities.

Active Tumoral/Tumor Environmental Dual-Targeting by Non-Covalently Arming with Trispecific Antibodies or Dual-Bispecific Antibodies on Docetaxel-Loaded mPEGylated Nanocarriers to Enhance Chemotherapeutic Efficacy and Minimize Systemic Toxicity.

PURPOSE: This study was aimed at developing the trispecific antibodies (anti-EGFR/anti-FAP/anti-mPEG, TsAb) or dual bispecific antibodies (anti-EGFR/anti-mPEG and anti-FAP/anti-mPEG) docetaxel (DTX)-loaded mPEGylated lecithin-stabilized micelles (mPEG-lsbPMs) for improving the targeting efficiency and therapeutic efficacy. METHODS: mPEG-lsbPMs were simply prepared via thin film method. The trispecific antibodies or bispecific antibodies bound the mPEG-lsbPMs by anti-mPEG Fab fragment. The formulations were characterized by DLS and TEM; in vitro and in vivo studies were also conducted to evaluate the cellular uptake, cell cytotoxicity and therapeutic efficacy. RESULTS: The particle sizes of mPEG-lsbPMs with or without the antibodies were around 100 nm; the formulations showed high encapsulation efficiencies of 97.12%. The TsAb and dual bispecific antibodies were fabricated and demonstrated their targeting ability. Two EGFR-overexpressed cell lines (HT-29 and MIA PaCa-2) were co-cultured with FAP-overexpressed WS1 cells (HT-29/WS1; MIA PaCa-2/WS1) to mimic a tumor coexisting in the tumor microenvironment. Cellular binding study revealed that the binding of anti-FAP micelles to three co-culture ratios (4:1, 1:1, and 1:4) of HT-29/EGFR to WS1/FAP was significantly higher than that for TsAb micelles and dual (1:1) micelles, and the binding of those targeting antibodies to WS1/FAP and MIA PaCa-2/EGFR was equally efficacious resulting in a similar binding amount of the TsAb and dual BsAbs (1:1) with the co-culture of MIA PaCa-2/EGFR and WS1/FAP at a 1:1 ratio. Antitumor efficacy study showed that treatment with DTX-loaded mPEG-lsbPMs modified with or without BsAbs, dual BsAbs (1:1), and TsAbs was enhanced in inhibiting tumor growth compared with that for Tynen® while showing fewer signs of adverse effects. CONCLUSION: Active targeting of both tumors and TAF-specific antigens was able to increase the affinity of DTX-loaded mPEG-lsbPMs toward tumor cells and TAFs leading to successive uptake by tumor cells or TAFs which enhanced their chemotherapeutic efficacy against antigen-positive cancer cells.

Does Cost-Effectiveness Analysis Overvalue Potential Cures? Exploring Alternative Methods for Applying a "Shared Savings" Approach to Cost Offsets.

OBJECTIVES: To evaluate alternative methods to calculate and/or attribute economic surplus in the cost-effectiveness analysis of single or short-term therapies. METHODS: We performed a systematic literature review of articles describing alternative methods for cost-effectiveness analysis of potentially curative therapies whose assessment using traditional methods may suggest unaffordable valuations owing to the magnitude of estimated long-term quality-adjusted life-year (QALY) gains or cost offsets. Through internal deliberation and discussion with staff at the Health Technology Assessment bodies in England and Canada, we developed the following 3 alternative methods for further evaluation: (1) capping annual costs in the comparator arm at $150 000 per year; (2) "sharing" the economic surplus with the health sector by apportioning only 50% of cost offsets or 50% of cost offsets and QALY gains to the value of the therapy; and (3) crediting the therapy with only 12 years of the average annual cost offsets or cost offsets and QALY gains over the lifetime horizon. The impact of each alternative method was evaluated by applying it in an economic model of 3 hypothetical condition-treatment scenarios meant to reflect a diversity of chronicity and background healthcare costs. RESULTS: The alternative with greatest impact on threshold price for the fatal pediatric condition spinal muscular atrophy type 1 was the 12-year cutoff scenario. For a hypothetical one-time treatment for hemophilia A, capping cost offsets at $150 000 per year had the greatest impact. For chimeric antigen receptor T-cell treatment of non-Hodgkin's lymphoma, capping cost offsets or using 12-year threshold had little impact, whereas 50% sharing of surplus including QALY gains and cost offsets greatly reduced threshold pricing. CONCLUSIONS: Health Technology Assessment bodies and policy makers will wrestle with how to evaluate single or short-term potentially curative therapies and establish pricing and payment mechanisms to ensure sustainability. Scenario analyses using alternative methods for calculating and apportioning economic surplus can provide starkly different assessment results. These methods may stimulate important societal dialogue on fair pricing for these novel treatments.

A bispecific antibody agonist of the IL-2 heterodimeric receptor preferentially promotes in vivo expansion of CD8 and NK cells.

The use of recombinant interleukin-2 (IL-2) as a therapeutic protein has been limited by significant toxicities despite its demonstrated ability to induce durable tumor-regression in cancer patients. The adverse events and limited efficacy of IL-2 treatment are due to the preferential binding of IL-2 to cells that express the high-affinity, trimeric receptor, IL-2Rαßγ such as endothelial cells and T-regulatory cells, respectively. Here, we describe a novel bispecific heavy-chain only antibody which binds to and activates signaling through the heterodimeric IL-2Rßγ receptor complex that is expressed on resting T-cells and NK cells. By avoiding binding to IL-2Rα, this molecule circumvents the preferential T-reg activation of native IL-2, while maintaining the robust stimulatory effects on T-cells and NK-cells in vitro. In vivo studies in both mice and cynomolgus monkeys confirm the molecule's in vivo biological activity, extended pharmacodynamics due to the Fc portion of the molecule, and enhanced safety profile. Together, these results demonstrate that the bispecific antibody is a safe and effective IL-2R agonist that harnesses the benefits of the IL-2 signaling pathway as a potential anti-cancer therapy.

Switchable CAR-T Cells Outperformed Traditional Antibody-Redirected Therapeutics Targeting Breast Cancers.

Various antibody-redirected immunotherapeutic approaches, including antibody-drug conjugates (ADCs), bispecific antibodies (bsAbs), and chimeric antigen receptor-T (CAR-T) cells, have been devised to produce specific activity against various cancer types. Using genetically encoded unnatural amino acids, we generated a homogeneous Her2-targeted ADC, a T cell-redirected bsAb, and a FITC-modified antibody capable of redirecting anti-FITC CAR-T (switchable CAR-T; sCAR-T) cells to target different Her2-expressing breast cancers. sCAR-T cells showed activity against Her2-expressing tumor cells comparable to that of conventional anti-Her2 CAR-T cells and superior to that of ADC- and bsAb-based approaches. To prevent antigen escape, we designed bispecific sCAR-T cells targeting both the Her2 receptor and IGF1R, which showed an overall improved activity against cancer cells with low Her2 expression. This study increases our understanding of various explored cancer therapeutics and underscores the efficient application of sCAR-T cells as a promising therapeutic option for breast cancer patients with low or heterogeneous antigen expression.

The changing treatment landscape in haemophilia: from standard half-life clotting factor concentrates to gene editing.

Congenital haemophilia A (factor VIII deficiency) and B (factor IX deficiency) are X-linked bleeding disorders. Replacement therapy has been the cornerstone of the management of haemophilia, aiming to reduce the mortality and morbidity of chronic crippling arthropathy. Frequent intravenous injections are burdensome and costly for patients, consequently with poor adherence and restricted access to therapy for many patients worldwide. Bioengineered clotting factors with enhanced pharmacokinetic profiles can reduce the burden of treatment. However, replacement therapy is associated with a risk for inhibitor development that adversely affects bleeding prevention and outcomes. Novel molecules that are subcutaneously delivered provide effective prophylaxis in the presence or absence of inhibitors, either substituting for the procoagulant function of clotting factors (eg, emicizumab) or targeting the natural inhibitors of coagulation (ie, antithrombin, tissue factor pathway inhibitor, or activated protein C). The ultimate goal of haemophilia treatment would be a phenotypical cure achievable with gene therapy, currently under late phase clinical investigation.

Quantitative Clinical Pharmacology of T-Cell Engaging Bispecifics: Current Perspectives and Opportunities.

T-cell directing/engaging bispecifics (TDBs) enable a powerful mode of action by activating T-cells through the creation of artificial immune synapses. Their pharmacological response involves the dynamic inter-relationships among T-cells, tumor cells, and TDBs. This results in complex and challenging issues in understanding pharmacokinetics, tissue distribution, target engagement, and exposure-response relationship. Dosing strategy plays a crucial role in determining the therapeutic window of TDBs because of the desire to maximize therapeutic efficacy in the context of known mechanism-related adverse events, such as cytokine release syndrome and neurological adverse events. Such adverse events are commonly reported as the most prominent events during the initial treatment cycles and dissipate over time. Therefore, the kinetic characterization of the inter-relationships between exposure/target engagement and safety/efficacy outcomes is crucial in designing the optimal dosing regimen to maximize the benefit/risk of TDB agents. In this review, we discuss the key clinical pharmacological considerations in drug discovery and development for TDBs and provide a summary of TDBs currently in clinical development. We also propose forward-looking perspectives and opportunities to derive insights through quantitative clinical pharmacology approaches.

Activated Coagulation Time and Hepcon Protamine Titration Device to Manage Unfractionated Heparin During Cardiopulmonary Bypass in a Hemophilia A Patient on Emicizumab.

In the perioperative management of patients with hemophilia A, emicizumab prevents the accurate measurement of common clotting assays, including the activated clotting time (ACT), which is essential for high-dose heparin monitoring during cardiopulmonary bypass surgery. The authors describe the successful perioperative management of a hemophilia A patient on maintenance emicizumab who, following a non-ST myocardial infarction, underwent cardiopulmonary bypass grafting surgery with heparin monitoring using both the ACT and heparin levels from the Hepcon protamine titration device. Postoperatively, the patient was transitioned to recombinant factor VIII replacement therapy. In hemophilia A patients on emicizumab who require heparin titration on cardiopulmonary bypass surgery, the ACT, combined with Hepcon heparin levels, may be used to complete the surgery successfully without excessive bleeding or morbidity.

Pasotuxizumab, a BiTE® immune therapy for castration-resistant prostate cancer: Phase I, dose-escalation study findings.

Aim: We report results of a first-in-human study of pasotuxizumab, a PSMA bispecific T-cell engager (BiTE®) immune therapy mediating T-cell killing of tumor cells in patients with advanced castration-resistant prostate cancer. Patients & methods: We assessed once-daily subcutaneous (SC) pasotuxizumab. All SC patients developed antidrug antibodies; therefore, continuous intravenous (cIV) infusion was assessed. Results: A total of 47 patients received pasotuxizumab (SC: n = 31, 0.5-172 µg/d; cIV: n = 16, 5-80 µg/d). The SC maximum tolerated dose was 172.0 µg/d. A sponsor change stopped the cIV cohort early; maximum tolerated dose was not determined. PSA responders occurred (>50% PSA decline: SC, n = 9; cIV, n = 3), including two long-term responders. Conclusion: Data support pasotuxizumab safety in advanced castration-resistant prostate cancer and represent evidence of BiTE monotherapy efficacy in solid tumors. Clinical trial registration: NCT01723475 (ClinicalTrials.gov).

Combination therapy with B7H3-redirected bispecific antibody and Sorafenib elicits enhanced synergistic antitumor efficacy.

Rationale: Current traditional treatment options are frequently ineffective to fight against ovarian cancer due to late diagnosis and high recurrence. Therefore, there is a vital need for the development of novel therapeutic agents. B7H3, an immune checkpoint protein, is highly expressed in various cancers, representing it a promising target for cancer immunotherapy. Although targeting B7H3 by bispecific T cell-engaging antibodies (BiTE) has achieved successes in hematological malignancies during recent years, attempts to use them for the treatment of solid cancers are less favorable, in part due to the heterogeneity of tumors. Sorafenib is an unselective inhibitor of multiple kinases currently being tested in clinical trials for several tumors, including ovarian cancer which showed limited activity and inevitable side effect for ovarian cancer treatment. However, it is able to enhance antitumor immune response, which indicates sorafenib may improve the efficiency of immunotherapy. Methods: We evaluated the expression of B7H3 in ovarian cancer using online database and validated its expression of tumor tissues by immunohistochemistry staining. Then, B7H3 expression and the effects of sorafenib on ovarian cancer cell lines were determined by flow cytometry. In addition, 2D and 3D ovarian cancer models were established to test the combined therapeutic effect in vitro. Finally, the efficiency of B7H3×CD3 BiTE alone and its combination with sorafenib were evaluated both in vitro and in vivo. Results: Our data showed that B7H3 was highly expressed in ovarian cancer compared with normal samples. Treatment with sorafenib inhibited ovarian cancer cell proliferation and induced a noticeable upregulation of B7H3 expression level. Further study suggested that B7H3×CD3 BiTE was effective in mediating T cell killing to cancer cells. Combined treatment of sorafenib and B7H3×CD3 BiTE had synergistic anti-tumor effects in ovarian cancer models. Conclusions: Overall, our study indicates that combination therapy with sorafenib and B7H3×CD3 BiTE may be a new therapeutic option for the further study of preclinical treatment of OC.

Development and clinical application of bispecific antibody in the treatment of colorectal cancer.

INTRODUCTION: Treatment of colorectal cancer as one of the most commonly diagnosed and a frequent cause of cancer-related deaths is of great challenges in health-related issues. AREAS COVERED: Immunotherapy is the fourth pillar of cancer treatment which provides more novel therapeutic options with expanding investigational potentials. One of the modalities in immunotherapy is the use of bispecific antibodies. Despite demonstrating many promising roles, it still needs more advanced studies to identify the actual pros and cons. In this review, the application of bispecific antibody in the treatment of colorectal cancer has been explained, based on preclinical and clinical studies. The literature search was conducted mainly through PubMed in June and September 2019. EXPERT OPINION: Bispecific antibody is in its early stages in colorectal cancer treatment, requiring modern technologies in manufacturing, better biomarkers and more specific target antigens, more studies on individual genetic variations, and conducting later phase clinical trials and systematic reviews to achieve better survival benefits.

High-Throughput Generation of Bipod (Fab × scFv) Bispecific Antibodies Exploits Differential Chain Expression and Affinity Capture.

Generation of bispecific antibodies (BsAbs) having two unique Fab domains requires heterodimerization of the two heavy chains and pairing of each heavy chain with its cognate light chain. An alternative bispecific scaffold (Bipod) comprising an scFv and a Fab on a heterodimeric Fc eliminates the possibility of light chain mispairing. However, unpredictable levels of chain expression and scFv-induced aggregation can complicate purification and reduce the yield of desired Bipod. Here, we describe a high-throughput method for generation of Bipods based on protein A and CH1 domain affinity capture. This method exploits over-expression of the scFv chain to maximize heterodimer yield. Bipods purified by this method have purity suitable for cell-based functional assays and in vivo studies.

Emicizumab Improves Ex Vivo Clotting Function in Patients with Mild/Moderate Hemophilia A.

BACKGROUND: Emicizumab prophylaxis is a promising treatment that reduces bleeding events in severely affected patients with hemophilia A (PwHA). It is anticipated that emicizumab could be similarly effective in mild/moderate PwHA (PwMHA) although this effect has not been investigated. AIM: We evaluated ex vivo coagulant effects of emicizumabin PwMHA. METHODS: Clot waveform analysis (CWA) triggered by prothrombin time/activated partial prothrombin time-mixed reagents was utilized to examine coagulant effects of emicizumabin factor (F)VIII-deficient plasma mixed with recombinant (r)FVIIIand in native plasmas from 16 PwMHA. The CWA parameter, adjusted-|min1| (Ad|min1|), was used. Increases in Ad|min1| (ΔAd|min1|) mediated by emicizumab were calculated from the slopes of regression lines in the presence of rFVIII. RESULTS: Ad|min1| in FVIII-deficient plasma with various concentrations of rFVIII negatively correlated with ΔAd|min1|by adding emicizumab, and these data were defined as standard reference values. Ad|min1| (4.57 ± 0.50) in 16 PwMHA increased to 5.05 ± 0.54 and 5.37 ± 0.60 by adding emicizumab at 50 and 100 µg/mL, respectively, but remained lower than the normal range (7.22 ± 0.21). ΔAd|min1| levels were 1.5 to 2-fold higher in five cases and 0.4 to 0.6-fold lower in four cases, compared with reference values determined by rFVIII. In some cases, genetic analyses suggested that specific point mutations could have contributed to these findings. Further studies using rFVIII mutants indicated, however, that the differences in ΔAd|min1| were not related to individual FVIII gene defects. CONCLUSION: Emicizumab enhances coagulation potential in PwMHA. Assessment of ex vivo coagulant activity of emicizumab could be helpful for predicting coagulant potentials prior to treatment in these patients.