Approved Monoclonal Antibodies Research Articles

Phase 3 study results of isatuximab, bortezomib, lenalidomide, and dexamethasone (Isa-VRd) versus VRd for transplant-ineligible patients with newly diagnosed multiple myeloma (IMROZ).

7500 Background: The first line of treatment (tx) is important for patients (pts) with newly diagnosed multiple myeloma (NDMM) as pts may not have a chance for subsequent therapy. VRd is currently a standard of care (SOC) in NDMM. Isa is an approved anti-CD38 monoclonal antibody (mAb) inducing myeloma cell death through multiple mechanisms. In the Phase 3 IMROZ study (NCT03319667), we investigate the efficacy and safety of Isa-VRd vs VRd in transplant-ineligible NDMM pts. Methods: IMROZ is a global, prospective, randomized, open-label study done at 102 study sites in 21 countries. Included pts had active, measurable NDMM not considered for transplant due to elderly age or comorbidities. Pts aged ≥80 were excluded. Pts were randomized 3:2 and stratified by age, R-ISS stage and China vs non-China, to receive Isa-VRd or VRd. Isa-VRd arm pts received Isa (10 mg/kg IV); both arms received V (1.3 mg/m2 SC), R (25 mg PO) and d (20 mg IV/PO). The primary endpoint was progression-free survival (PFS). Key secondary endpoints were complete response (CR), minimal residual disease negativity (MRD-) (10-5 by NGS) in pts with CR, very good partial response or better and overall survival. Adverse events (AEs) and laboratory parameters were graded with NCI CTCAE v4.03. Results: 446 pts (265 Isa-VRd, 181 VRd) were randomized; pt characteristics were well balanced. At data cutoff (26 Sep 2023), 125 (47.2%) and 44 (24.3%) pts in Isa-VRd and VRd arms were still on tx, respectively. Median (mdn) tx duration was 53.2 (Isa-VRd) vs 31.3 (VRd) mo; addition of Isa did not significantly affect relative dose intensity of VRd. At mdn follow-up of 59.7 mo, mdn PFS was not reached (Isa-VRd) vs 54.3 mo (VRd); HR 0.596 (98.5% CI 0.406–0.876), log-rank p=0.0005. From the current trend, projected Isa-VRd mdn PFS will reach ~90 mo. PFS benefit was consistent across subgroups and maintained through subsequent line of therapy (PFS2 HR 0.697; 95% CI: 0.51-0.952). Isa-VRd led to deep and sustained responses and was well-tolerated (Table). Exposure-adjusted Grade 5 TEAE rate was 0.03 (Isa-VRd) vs 0.02 (VRd). Conclusions: IMROZ is the first Phase 3 study of an anti-CD38 mAb with SOC VRd in this pt population to show a significantly reduced risk of progression or death by 40.4% vs VRd while providing deep and sustained responses. The safety profile was consistent with addition of Isa to VRd. Numerical differences in TEAEs are largely explained by longer exposure in the Isa-VRd arm. These results support Isa-VRd as a potential new SOC in pts not intended for transplant. Clinical trial information: NCT03319667 . [Table: see text]

Nonintuitive Immunogenicity and Plasticity of Alpha-Synuclein Conformers: A Paradigm for Smart Delivery of Neuro-Immunotherapeutics.

Despite the extensive research successes and continuous developments in modern medicine in terms of diagnosis, prevention, and treatment, the lack of clinically useful disease-modifying drugs or immunotherapeutic agents that can successfully treat or prevent neurodegenerative diseases is an ongoing challenge. To date, only one of the 244 drugs in clinical trials for the treatment of neurodegenerative diseases has been approved in the past decade, indicating a failure rate of 99.6%. In corollary, the approved monoclonal antibody did not demonstrate significant cognitive benefits. Thus, the prevalence of neurodegenerative diseases is increasing rapidly. Therefore, there is an urgent need for creative approaches to identifying and testing biomarkers for better diagnosis, prevention, and disease-modifying strategies for the treatment of neurodegenerative diseases. Overexpression of the endogenous α-synuclein has been identified as the driving force for the formation of the pathogenic α-synuclein (α-Syn) conformers, resulting in neuroinflammation, hypersensitivity, endogenous homeostatic responses, oxidative dysfunction, and degeneration of dopaminergic neurons in Parkinson's disease (PD). However, the conformational plasticity of α-Syn proffers that a certain level of α-Syn is essential for the survival of neurons. Thus, it exerts both neuroprotective and neurotoxic (regulatory) functions on neighboring neuronal cells. Furthermore, the aberrant metastable α-Syn conformers may be subtle and difficult to detect but may trigger cellular and molecular events including immune responses. It is well documented in literature that the misfolded α-Syn and its conformers that are released into the extracellular space from damaged or dead neurons trigger the innate and adaptive immune responses in PD. Thus, in this review, we discuss the nonintuitive plasticity and immunogenicity of the α-Syn conformers in the brain immune cells and their physiological and pathological consequences on the neuroimmune responses including neuroinflammation, homeostatic remodeling, and cell-specific interactions that promote neuroprotection in PD. We also critically reviewed the novel strategies for immunotherapeutic delivery interventions in PD pathogenesis including immunotherapeutic targets and potential nanoparticle-based smart drug delivery systems. It is envisioned that a greater understanding of the nonintuitive immunogenicity of aberrant α-Syn conformers in the brain's microenvironment would provide a platform for identifying valid therapeutic targets and developing smart brain delivery systems for clinically effective disease-modifying immunotherapeutics that can aid in the prevention and treatment of PD in the future.

Abstract 7528: Coordinated regulation of critical immune checkpoint proteins by the integrated stress response (ISR) pathway in lung cancer

Abstract Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide. Despite recent advances, high rates of recurrence highlight the need for novel treatment options. Groundbreaking discoveries in identifying and exploiting the PD-1/PD-L1 (Programmed Death 1/Programmed Death Ligand 1) immune checkpoint have resulted in the approval of monoclonal antibodies that disrupt this interaction as a first-line therapy for lung cancer patients. However, only ~20% of NSCLC patients benefit from checkpoint blockade. A critical question remains as to what mechanisms facilitate resistance to PD-1/PD-L1 therapy and whether other immune checkpoints or pathways can be pursued clinically in combination with this therapy. The integrated stress response (ISR) pathway represents an emerging therapeutic vulnerability. The ISR is a generalized response to maintain cellular homeostasis, and is known to be activated by hypoxia, heme deprivation, amino acid starvation, and oncogenic activation. We previously demonstrated that ISR activation potently induces PD-L1 in NSCLC and suppression of anti-tumor immunity (Suresh et al, Nature Cancer, 2020). We discovered that ISR pathway activation enhances PD-L1 translation through the bypass of inhibitory upstream open reading frames (uORFs) in the PD-L1 5' UTR and a mechanistic link to the translation initiation factor eIF5B. Our latest studies demonstrate that the immune checkpoint protein, CD155 (Cluster of Differentiation 155), is induced by ISR activation. We find that both PD-L1 and CD155 are induced by multiple arms of the ISR pathway, and CD155 harbors inhibitory uORFs in its 5' UTR. Importantly, we observed a significant correlation between PD-L1 and CD155 expression in a panel of primary human lung adenocarcinomas. We further demonstrated that ISR activation inhibits T cell function in vitro and promotes tumor growth in the CMT167 syngeneic mouse model. Analysis of immune cell infiltration using mass cytometry in this in vivo model is ongoing. Currently, we are determining the extent to which ISR inhibition suppresses tumorigenesis by promoting anti-tumor immunity and whether this may synergize with existing immune checkpoint therapies. Overall, these studies will set the stage for determining whether inhibition of the ISR pathway alone or in combination with immune checkpoint blockade will benefit lung cancer patients. Our studies may also lead to new therapeutic approaches to trigger anti-cancer immune responses and improve current strategies. Citation Format: Shayna Elizabeth Thomas-Jardin, Shruthy Suresh, Cheryl Lewis, Chul Ahn, Bret M. Evers, John D. Minna, Kathryn A. O'Donnell. Coordinated regulation of critical immune checkpoint proteins by the integrated stress response (ISR) pathway in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7528.

Abstract 5232: Placental circulating T cells expressing CD16 in combination with trastuzumab demonstrate robust anti-tumor antibody-dependent cellular cytotoxicity (ADCC) against gastric cancer

Abstract Introduction: Celularity is developing PT-CD16VS as a novel platform for use in combination with approved monoclonal antibodies for the potential treatment of multiple cancers. PT-CD16VS is an allogeneic cell therapy derived from human postpartum placental circulating T (P-T) cells that are genetically modified to express a proprietary CD16 variant and endogenous T cell receptor (TCR) knockout. Here we report the characterization and preclinical evaluation of PT-CD16VS against HER2+ gastric cancer cells in combination with Trastuzumab. In vitro safety studies evaluating the potential for on-target/off-tumor activity of PT-CD16VS against HER2 low expressing lung epithelial cells (LEC) and human dermal fibroblasts (HDF) are also highlighted. Methods: P-T cells were activated and transduced with a lentiviral vector containing a CD16 construct expressing a high affinity CD16 variant, CD16VS. Following transduction, P-T cells were transfected to knock out the TCR. In vitro, the functional activity of PT-CD16VS cells in combination with Trastuzumab was assessed against the HER2+ gastric cancer NCI-N87 cell line in cytotoxicity, cytokine release, and proliferation assays. For on-target/off-tumor studies, similar assays were utilized to assess activity against the HER2 low expressing LEC and HDF cell lines. In vivo, PT-CD16VS with Trastuzumab was evaluated in a subcutaneous NCI-N87 xenograft model in NSG mice. Tumor volume was measured and tumor samples were evaluated for PT-CD16VS infiltration. Results: High CD16 transduction efficiency (>60%) was achieved across donors. In vitro, PT-CD16VS plus Trastuzumab demonstrated potent cytotoxicity against NCI-N87 cells at low E:T ratios (0.625:1) and at 12 hours of co-culture with moderate cytokine secretion at 24-hour of co-culture. PT-CD16VS proliferated following 48-hour incubation with NCI-N87 cells and Trastuzumab, as compared to an IgG1 control. PT-CD16VS in combination with Trastuzumab did not elicit on-target/off-tumor cytotoxicity or cytokine release in response to low HER2 expression on normal LEC or HDF cells. In vivo, PT-CD16VS with Trastuzumab demonstrated significant reduction in tumor volume compared to vehicle, Trastuzumab alone, and the positive control Enhertu groups. In addition, PT-CD16VS infiltration into the tumor was shown to be Trastuzumab dependent, with infiltrating cells expressing high levels of CD16 and Ki67. Conclusions: Our results show that PT-CD16VS has robust in vitro and in vivo ADCC activity against gastric cancer tumor cells when combined with Trastuzumab. Furthermore, PT-CD16VS activity is specific to tumor HER2 antigen expression and does not target low HER2 expression on normal healthy cells. PT-CD16VS is being developed in combination with various monoclonal antibodies for the treatment of multiple cancers. Citation Format: Kathy Karasiewicz-Mendez, Joseph Gleason, Kristina Tess, Mansour Djedaini, Shengchen Lin, Chenfei Huang, Shuyang He, Robert Hariri, Adrian Kilcoyne. Placental circulating T cells expressing CD16 in combination with trastuzumab demonstrate robust anti-tumor antibody-dependent cellular cytotoxicity (ADCC) against gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5232.

Neutralizing activity of anti-respiratory syncytial virus monoclonal antibody produced in Nicotiana benthamiana

ABSTRACT Respiratory syncytial virus (RSV) is a highly contagious virus that affects the lungs and respiratory passages of many vulnerable people. It is a leading cause of lower respiratory tract infections and clinical complications, particularly among infants and elderly. It can develop into serious complications such as pneumonia and bronchiolitis. The development of RSV vaccine or immunoprophylaxis remains highly active and a global health priority. Currently, GSK’s Arexvy™ vaccine is approved for the prevention of lower respiratory tract disease in older adults (>60 years). Palivizumab and currently nirsevimab are the approved monoclonal antibodies (mAbs) for RSV prevention in high-risk patients. Many studies are ongoing to develop additional therapeutic antibodies for preventing RSV infections among newborns and other susceptible groups. Recently, additional antibodies have been discovered and shown greater potential for development as therapeutic alternatives to palivizumab and nirsevimab. Plant expression platforms have proven successful in producing recombinant proteins, including antibodies, offering a potential cost-effective alternative to mammalian expression platforms. Hence in this study, an attempt was made to use a plant expression platform to produce two anti-RSV fusion (F) mAbs 5C4 and CR9501. The heavy-chain and light-chain sequences of both these antibodies were transiently expressed in Nicotiana benthamiana plants using a geminiviral vector and then purified using single-step protein A affinity column chromatography. Both these plant-produced mAbs showed specific binding to the RSV fusion protein and demonstrate effective viral neutralization activity in vitro. These preliminary findings suggest that plant-produced anti-RSV mAbs are able to neutralize RSV in vitro.

Spatially Resolved Transcriptomics Reveals Local Invasion-Related Genes in Liver Hepatocellular Carcinoma: Exploring the Therapeutic Potential of a Chimeric Protein Targeting Glypican-3

Despite advancements in cancer therapy, hepatocellular carcinoma (HCC) remains a major health concern due to late-stage diagnosis and poor prognosis. In this study, the expression of Glypican-3 (GPC3), a cell surface protein encoded by the GPC3 gene was analyzed at both Messenger RNA and protein levels. The goal was to advance understandings into the role of GPC3 in HCC progression and design a fusion protein as a potential therapy targeting cancer cells expressing this oncogene. Expression analysis of GPC3 in liver hepatocellular carcinoma (LIHC) was performed using GEPIA 2 and OncoDB servers. The analysis revealed a significantly high expression level of GPC3 in cancerous tissues of HCC, with a p-value of p = 1.07e-37. This finding indicates the potential involvement of GPC3 in HCC development. To construct the chimeric proteins (CPs), rituximab, a linker, and an approved Anti-Ogawa O-antigen monoclonal antibody S-20-4 penetrating peptide were combined using trRosetta. The peptide sequence of the Anti-Ogawa O-antigen monoclonal antibody S-20-4, namely, NHNYPPLSLLTF, SHDWRLMLSHLQ, QHDRLLMLSYLV, HHILPPKALLFG, SHTFPPSWLLVR and YSVKPPLPYLPP was obtained from the Immunet BDB database. The HDock scoring algorithms were employed to assess the degree of connection between the CP and the GPC3 gene expressed in HCC. The analysis showed a strong binding affinity of -258.53 KJ/mol between the CP and GPC3, indicating a favorable interaction. Simulations and toxicity analysis further supported the therapeutic potential of the constructed CP for treating LIHC. These findings highlight the potential of the CP as a targeted therapy against HCC, leveraging the high expression of GPC3 in cancerous tissues.

Abstract C069: Toripalimab an anti-PD-1 antibody that demonstrates potent T cell activation and enhanced clinical efficacy irrespective of PD-L1 status

Abstract Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) have revolutionized cancer treatment favoring prognostic benefits to a broad range of cancer patients. Currently, US Food and Drug Administration (FDA)–approved PD-1 monoclonal antibodies (mAbs) have demonstrated significant clinical benefit, particularly in patients with programmed cell death ligand 1 (PD-L1)-expressing tumors. Toripalimab is a PD-1 targeting humanized IgG4 mAb that is currently pending approval by the FDA as a first-line treatment for patients with recurrent or metastatic nasopharyngeal carcinoma (RM-NPC). In combination with chemotherapy, toripalimab demonstrated significant clinical efficacy irrespective of PD-L1 status in patients in three different clinical trials, namely JUPITER-02 (NPC), JUPITER-06 (esophageal squamous cell carcinoma [ESCC]) and CHOICE-01 (non-small cell lung cancer [NSCLC]). Here we investigated the molecular and functional characteristics of toripalimab and compared it to pembrolizumab, a PD-1 mAb that is approved in the largest number of indications in the PD-1 mAb class. In comparison to pembrolizumab, toripalimab demonstrated a 12-fold higher binding affinity to PD-1 and selectively induced higher Th1 and myeloid derived inflammatory cytokine responses in human peripheral blood mononuclear cells (PBMCs). Upon treating dissociated tumor cells from treatment naïve NSCLC patients, toripalimab demonstrated an enhanced expression of several unique genes in interferon gamma and immune cell pathways compared to pembrolizumab. The binding of toripalimab to PD-1 ectopically expressed in Jurkat T cells, recruited lower levels of SHP1 and SHP2, the negative regulators of T cell activation, compared to pembrolizumab. Overall, our study demonstrates that toripalimab is differentiated from pembrolizumab in terms of stronger PD-1 binding, more potent in-vitro T cell activation and lower agonistic potential. These characteristics of toripalimab present it as a next generation PD-1 checkpoint inhibitor with potential for favorable clinical outcomes in treating cancer patients irrespective of their PD-L1 status. Citation Format: Xiaoguang Wang, Sruthi Ravindranathan, Daniel Chin, Su-Yi Tseng, Scott Klakamp, Kate Widmann, Varun Kapoor, Vladimir Vexler, Patricia Keegan, Sheng Yao, Sanjay D Khare, Theresa LaVallee, Narendiran Rajasekaran. Toripalimab an anti-PD-1 antibody that demonstrates potent T cell activation and enhanced clinical efficacy irrespective of PD-L1 status [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C069.

Aerosol Delivery of Palivizumab in a Neonatal Lamb Model of Respiratory Syncytial Virus Infection.

(1) Background: Palivizumab has been an approved preventative monoclonal antibody for respiratory syncytial virus (RSV) infection for over two decades. However, due to its high cost and requirement for multiple intramuscular injections, its use has been limited mostly to high-income countries. Following our previous study showing the successful lung deposition of aerosolised palivizumab in lambs, this current study evaluated the "proof-of-principle" effect of aerosolised palivizumab delivered as a therapeutic to neonatal lambs following RSV infection. (2) Methods: Neonatal lambs were intranasally inoculated with RSV-A2 on day 0 (day 3 post-birth) and treated with aerosolised palivizumab 3 days later (day 3 post-inoculation). Clinical symptoms, RSV viral load and inflammatory response were measured post-inoculation. (3) Results: Aerosolised therapeutic delivery of palivizumab did not reduce RSV viral loads in the nasopharynx nor the bronchoalveolar lavage fluid, but resulted in a modest reduction in inflammatory response at day 6 post-inoculation compared with untreated lambs. (4) Conclusions: This proof-of-principle study shows some evidence of aerosolised palivizumab reducing RSV inflammation, but further studies using optimized protocols are needed in order to validate these findings.

CTIM-10. A SURGICAL WINDOW-OF-OPPORTUNITY CLINICAL TRIAL EVALUATING THE PCSK9 INHIBITOR EVOLOCUMAB IN PATIENTS WITH GLIOMA

Abstract Gliomas evade the immune system by downregulating cell surface expression of major histocompatibility class (MHC)-I. Antagonism of proprotein convertase subtilisin/kexin type 9 (PCSK9) increases MHC-I expression and can enhance checkpoint inhibition in vivo. Evolocumab is an FDA approved monoclonal antibody (mAb) for hyperlipidemia that inhibits PCSK9. However, large constructs such as mAbs typically have limited penetrance across the blood-brain-barrier. We report the preliminary results of a surgical window-of-opportunity study evaluating if Evolocumab administered subcutaneously pre-preoperatively is detectable in tumor tissue from patients with newly diagnosed or recurrent glioma (PESKe; NCT04937413). Twenty contemporaneous control samples are prospectively collected from patients undergoing craniotomy without receiving Evolocumab. Although non-randomized, these specimens provide valuable information for exploratory comparison of the treated and untreated specimens in terms of drug penetrance and MHC-I expression. To date, 24 patients have been enrolled (M: 14, F: 10) with a median age of 46.5. Of these, 5 received pre-procedure subcutaneous Evolocumab (420mg), while the remaining 19 were analyzed as controls. In treated patients, Evolocumab was detectable via mass spectroscopy (LC-MS/MS) in all analyzed cases, including in tumor tissue from both contrast-enhancing and non-contrast-enhancing regions. Ratios of drug in tumor relative to intra-operative blood were markedly higher in samples from contrast-enhancing regions compared to non-contrast enhancing regions (median ratio of tumor to blood of 0.1503 vs 0.0248 respectively). The tumor proteome was also analyzed using LC-MS/MS to quantitate MHC-I and MHC-II proteins. Initial analysis found increased MHC-I (HLA-A, HLA-B, HLA-C) quantitation via mass spectroscopic analysis of the tumor proteome in treated samples compared to contemporaneous untreated controls. No significant adverse events have been reported in those who received pre-procedure Evolocumab. Ongoing analyses will seek to determine whether increased MHC-I quantities in tumor correspond with increased cell surface expression via immunofluorescence and immunohistochemistry.

Determinants of passive antibody efficacy in SARS-CoV-2 infection: a systematic review and meta-analysis

Randomised controlled trials of passive antibodies as treatment and prophylaxis for COVID-19 have reported variable efficacy. However, the determinants of efficacy have not been identified. We aimed to assess how the dose and timing of administration affect treatment outcome. In this systematic review and meta-analysis, we extracted data from published studies of passive antibody treatment from Jan 1, 2019, to Jan 31, 2023, that were identified by searching multiple databases, including MEDLINE, PubMed, and ClinicalTrials.gov. We included only randomised controlled trials of passive antibody administration for the prevention or treatment of COVID-19. To compare administered antibody dose between different treatments, we used data on in-vitro neutralisation titres to normalise dose by antibody potency. We used mixed-effects regression and model fitting to analyse the relationship between timing, dose and efficacy. We found 58 randomised controlled trials that investigated passive antibody therapies for the treatment or prevention of COVID-19. Earlier clinical stage at treatment initiation was highly predictive of the efficacy of both monoclonal antibodies (p<0·0001) and convalescent plasma therapy (p=0·030) in preventing progression to subsequent stages, with either prophylaxis or treatment in outpatients showing the greatest effects. For the treatment of outpatients with COVID-19, we found a significant association between the dose administered and efficacy in preventing hospitalisation (relative risk 0·77; p<0·0001). Using this relationship, we predicted that no approved monoclonal antibody was expected to provide more than 30% efficacy against some omicron (B.1.1.529) subvariants, such as BQ.1.1. Early administration before hospitalisation and sufficient doses of passive antibody therapy are crucial to achieving high efficacy in preventing clinical progression. The relationship between dose and efficacy provides a framework for the rational assessment of future passive antibody prophylaxis and treatment strategies for COVID-19. The Australian Government Department of Health, Medical Research Future Fund, National Health and Medical Research Council, the University of New South Wales, Monash University, Haematology Society of Australia and New Zealand, Leukaemia Foundation, and the Victorian Government.

SARS-CoV-2 antibodies from children exhibit broad neutralization and belong to adult public clonotypes

From the beginning of the COVID-19 pandemic, children have exhibited different susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, reinfection, and disease compared with adults. Motivated by the established significance of SARS-CoV-2-neutralizing antibodies in adults, here we characterize SARS-CoV-2-specific antibody repertoires in a young cohort of individuals aged from 5months to 18 years old. Our results show that neutralizing antibodies in children possess similar genetic features compared to antibodies identified in adults, with multiple antibodies from children belonging to previously established public antibody clonotypes in adults. Notably, antibodies from children show potent neutralization of circulating SARS-CoV-2 variants that have cumulatively resulted in resistance to virtually all approved monoclonal antibody therapeutics. Our results show that children can rely on similar SARS-CoV-2 antibody neutralization mechanisms compared to adults and are an underutilized source for the discovery of effective antibody therapeutics to counteract the ever-evolving pandemic.

A survey of FDA Approved Monoclonal Antibodies and Fc-fusion Proteins for Manufacturing Changes and Comparability Assessment.

Manufacturing changes occur commonly throughout stages of biologics development and may result in product quality attribute changes. As changes in critical quality attributes have the potential to affect clinical safety and efficacy of products, it is imperative to ensure the quality and clinical performance before introducing the after-change products. Thus, we embarked on this project to understand what data have supported the manufacturing changes for licensed products with pre- and post-approval changes. We surveyed the manufacturing changes of 85 monoclonal antibodies and 10 Fc fusion proteins approved by the Food and Drug Administration as of December 25, 2021. After collecting the type and timing of changes for these products, we investigated the approaches that provided supporting data for the changes. The source documents included reports submitted by applicants and FDA's regulatory reviews. Analytical comparability was assessed to support all identified manufacturing changes. Supporting clinical data were available in 92% of these manufacturing changes; including data from pharmacokinetic comparability studies alone (3%), other studies on efficacy or safety (70%) and a combination of both (19%). Clinical pharmacokinetic comparability data contributed to supporting substantial changes, such as host cell type or master cell bank changes, concentration or formulation changes, and changes from pre-filled syringes to autoinjectors, especially when introduced after completing pivotal studies. Our comprehensive retrospective analysis provides an understanding of the regulatory experience and industry practice, which could facilitate developing appropriate comparability approaches to support manufacturing changes in the future.

Application of Computational Techniques in Antibody Fc-Fused Molecule Design for Therapeutics.

Since the advent of hybridoma technology in the year 1975, it took a decade to witness the first approved monoclonal antibody Orthoclone OKT39 (muromonab-CD3) in the year 1986. Since then, continuous strides have been made to engineer antibodies for specific desired effects. The engineering efforts were not confined to only the variable domains of the antibody but also included the fragment crystallizable (Fc) region that influences the immune response and serum half-life. Engineering of the Fc fragment would have a profound effect on the therapeutic dose, antibody-dependent cell-mediated cytotoxicity as well as antibody-dependent cellular phagocytosis. The integration of computational techniques into antibody engineering designs has allowed for the generation of testable hypotheses and guided the rational antibody design framework prior to further experimental evaluations. In this article, we discuss the recent works in the Fc-fused molecule design that involves computational techniques. We also summarize the usefulness of in silico techniques to aid Fc-fused molecule design and analysis for the therapeutics application.

In Vitro Antibody-Dependent Enhancement of SARS-CoV-2 Infection Could Be Abolished by Adding Human IgG.

Evidence of antibody-dependent enhancement (ADE) of other viruses has raised concerns about the safety of SARS-CoV-2 vaccines and antibody therapeutics. In vitro studies have shown ADE of SARS-CoV-2 infection. In this study, we also found that vaccination/convalescent sera and some approved monoclonal antibodies can enhance SARS-CoV-2 infection of FcR-expressing B cells in vitro. However, the enhancement of SARS-CoV-2 infection can be prevented by blocking Fc-FcR interaction through the addition of human serum/IgG or the introduction of mutations in the Fc portion of the antibody. It should be noted that ADE activity observed on FcR-expressing cells in vitro may not necessarily reflect the situation in vivo; therefore, animal and clinical data should be included for ADE evaluation.

De Novo Large Deletions in the PHEX Gene Caused X-Linked Hypophosphataemic Rickets in Two Italian Female Infants Successfully Treated with Burosumab.

Pathogenic variants in the PHEX gene cause rare and severe X-linked dominant hypophosphataemia (XLH), a form of heritable hypophosphatemic rickets (HR) characterized by renal phosphate wasting and elevated fibroblast growth factor 23 (FGF23) levels. Burosumab, the approved human monoclonal anti-FGF23 antibody, is the treatment of choice for XLH. The genetic and phenotypic heterogeneity of HR often delays XLH diagnoses, with critical effects on disease course and therapy. We herein report the clinical and genetic features of two Italian female infants with sporadic HR who successfully responded to burosumab. Their diagnoses were based on clinical and laboratory findings and physical examinations. Next-generation sequencing (NGS) of the genes associated with inherited HR and multiple ligation probe amplification (MLPA) analysis of the PHEX and FGF23 genes were performed. While a conventional analysis of the NGS data did not reveal pathogenic or likely pathogenic small nucleotide variants (SNVs) in the known HR-related genes, a quantitative analysis identified two different heterozygous de novo large intragenic deletions in PHEX, and this was confirmed by MLPA. Our molecular data indicated that deletions in the PHEX gene can be the cause of a significant fraction of XLH; hence, their presence should be evaluated in SNV-negative female patients. Our patients successfully responded to burosumab, demonstrating the efficacy of this drug in the treatment of XLH. In conclusion, the execution of a phenotype-oriented genetic test, guided by known types of variants, including the rarest ones, was crucial to reach the definitive diagnoses and ensure our patients of long-term therapy administration.

Clinical Significance of PD-L1 Status in Circulating Tumor Cells for Cancer Management during Immunotherapy.

The approval of monoclonal antibodies against programmed death-ligand 1 (PD-L1) and programmed cell death protein (PD1) has changed the landscape of cancer treatment. To date, many immune checkpoint inhibitors (ICIs) have been approved by the FDA for the treatment of metastatic cancer as well as locally recurrent advanced cancer. However, immune-related adverse events (irAEs) of ICIs highlight the need for biomarker analysis with strong predictive value. Liquid biopsy is an important tool for clinical oncologists to monitor cancer patients and administer or change appropriate therapy. CTCs frequently express PD-L1, and this constitutes a clinically useful and non-invasive method to assess PD-L1 status in real-time. This review summarizes all the latest findings about the clinical significance of CTC for the management of cancer patients during the administration of immunotherapy and mainly focuses on the assessment of PD-L1 expression in CTCs.

Preclinical and early clinical data of ZN-1041 in combination with trastuzumab deruxtecan to treat breast cancer with or without CNS metastases.

1041 Background: While treatment options for advanced HER2+ breast cancer have improved, HER2+ breast cancer brain metastases (BCBM) remain a clinical challenge warranting the development of additional, brain permeable HER2-targeted therapies. ZN-1041 is a brain permeable, selective HER2-targeted oral tyrosine kinase inhibitor. Preclinical studies have demonstrated efficacy and safety of ZN-1041 warranting clinical development alone and in combination with approved monoclonal antibodies or antibody drug conjugates for patients (pts) with HER2+ BCBM. Methods: Anti-tumor activity of ZN-1041 alone or in combination with trastuzumab emtansine (TDM1), trastuzumab deruxtecan (TDXd), or trastuzumab (H) plus pertuzumab (P) was evaluated in BT474 BM orthotopic xenograft models. ZN-A-1041-101-US (NCT05593094) is an on-going phase 1, multicenter, open-label study. The study comprises dose escalation of ZN-1041 monotherapy (Phase 1a) in pts with HER2+ solid tumors with or without BM, dose escalation (Phase 1b) and expansion (phase 1c) of ZN-1041 in combination with TDM1 (Arm 1), TDXd (Arm 2), or HP as maintenance therapy (Arm 3) in pts with HER2+ mBC with or without BM. The primary objectives were safety, tolerability and recommended phase 2 dose. The secondary objective includes pharmacokinetics (PK) and preliminary efficacy per RECIST 1.1. Results: Preclinically, ZN-1041 alone or combined with TDM1, TDXd or HP demonstrated significant improvement in intracranial tumor growth inhibition compared to TDM1, TDXd, or HP alone. As of data cutoff, Phase 1a (n = 7 pts) and Arm 2 of Phase 1b (n = 3 pts) were completed. Among 10 pts enrolled, 8 pts had received prior HER2 TKI. In Phase 1a, ZN-1041 was well tolerated with no dose-limiting toxicities (DLTs) or drug discontinuation due to toxicity up to a dose of 800 mg BID. Adverse reactions were mainly grade 1. The most common treatment related adverse reactions (TRAEs≥15%) were grade 1 nausea (43%) and vomiting (29%), with no ≥ grade 2 diarrhea reported. PK exposure was increased with dose escalation. In Phase 1a, one pt with mBC (without BM) achieved a confirmed partial response (PR) at 400 mg BID dose for &gt; 15 months; one with gastric cancer achieved stable disease at the first dose level of 50mg BID for nearly 1 year. In Phase 1b, pts who had previously progressed on TDXd and/or TKI were enrolled and received ZN-1041 at a dose of 800 mg BID in combination with TDXd. Combination therapy was well tolerated with no DLTs reported. One pt with BCBM who was previously on tucatinib and TDXd had a confirmed PR. Conclusions: Safety and tolerability was observed for ZN-1041 with maximum tolerated dose 800 mg BID as monotherapy and combined with TDXd in pts with advanced HER2+ malignancies. Encouraging efficacy was observed in treatment-refractory settings. Additional safety and efficacy data of ZN-1041 in combination with TDM1, TDXd or HP are warranted. Clinical trial information: NCT05593094 .

COVID-19 and Other Viral Infections in Patients With Hematologic Malignancies

COVID-19 and our armamentarium of strategies to combat it have evolved dramatically since the virus first emerged in late 2019. Vaccination remains the primary strategy to prevent severe illness, although the protective effect can vary in patients with hematologic malignancy. Strategies such as additional vaccine doses and now bivalent boosters can contribute to increased immune response, especially in the face of evolving viral variants. Because of these new variants, no approved monoclonal antibodies are available for pre-exposure or postexposure prophylaxis. Patients with symptomatic, mild-to-moderate COVID-19 and risk features for developing severe COVID-19, who present within 5-7 days of symptom onset, should be offered outpatient therapy with nirmatrelvir/ritonavir (NR) or in some cases with intravenous (IV) remdesivir. NR interacts with many blood cancer treatments, and reviewing drug interactions is essential. Patients with severe COVID-19 should be managed with IV remdesivir, tocilizumab (or an alternate interleukin-6 receptor blocker), or baricitinib, as indicated based on the severity of illness. Dexamethasone can be considered on an individual basis, weighing oxygen requirements and patients' underlying disease and their perceived ability to clear infection. Finally, as CD19-targeted and B-cell maturation (BCMA)-targeted chimeric antigen receptor (CAR) T-cell therapies become more heavily used for relapsed/refractory hematologic malignancies, viral infections including COVID-19 are increasingly recognized as common complications, but data on risk factors and prophylaxis in this patient population are scarce. We summarize the available evidence regarding viral infections after CAR T-cell therapy.

A Spike-Control Approach that Evaluates High Resolution Mass Spectrometry-Based Sequence Variant Analytical Method Performance for Therapeutic Proteins.

An amino acid sequence variant (SV) is defined as an unintended amino acid substitution in protein drug products. SVs contribute to product heterogeneity and can potentially impact product quality, safety, immunogenicity, and efficacy. The analysis of biotherapeutics for SVs is important throughout the product life cycle including clone selection, development of nutrient feed strategies, commercial manufacturing process, and post-approval changes to monitor product quality. The proposed analytical procedure for SVs consists of both qualitative (identification of SVs) and quantitative (quantitation of identified SVs) components. The complexities of SV analysis and the variety of current procedures highlight the need for a systematic approach for assessing the capability of these methodologies to reliably identify and quantitate SVs in biotherapeutics. We described here a "spike-control" approach for evaluating SV analytical procedure. The concept was adopted from quality control samples routinely used in analytical procedure validation. One FDA approved monoclonal antibody (mAb) was spiked with accurate amounts of highly homologous mAb to create mAb samples containing low yet accurate levels of "artificial" SVs. Spike-control samples were denatured, reduced, alkylated, digested and then analyzed by high resolution Orbitrap mass spectrometry. In silico analysis revealed four single amino acid differences between the two mAbs that could be used to represent SVs in the spike-control samples. All four "artificial" SVs were reliably identified by the current workflow. Analytical range (0.01% to 2%), accuracy and precision of identified SVs have also been evaluated. Overall, spike-control sample(s) helped to demonstrate that the SV analytical procedure (i.e., sample preparation, LC separation, mass spectrometry determinations and bioinformatic software) was fit for purpose and suitable for the identification and quantitation of SVs at a pre-determined threshold.

A systematic review and meta-analysis of extended interval dosing (EID) vs. standard-interval dosing (SID) of Natalizumab for multiple sclerosis patients. (P8-3.005)

<h3>Objective:</h3> We aimed to assess the difference in the efficacy and safety of the extended interval dosing (EID) regimen compared with the standard interval regimen (SID) of natalizumab for patients with multiple sclerosis (MS). <h3>Background:</h3> MS is an immune-mediated, chronic inflammatory disease of the central nervous system. Natalizumab is an approved monoclonal antibody against the α4β1 integrin receptor for MS. The SID is once every four weeks as a 300 mg intravenous infusion. Extending the interval dosing of natalizumab beyond four weeks has been suggested for potential superiority in safety with preserved efficacy. <h3>Design/Methods:</h3> We searched PubMed, Scopus, WOS, Embase, Ovid, Science Direct, Clinical trials.gov, and Cochrane Library for clinical trials published in English comparing EID with SID. We assessed the quality of the included studies using the Cochrane, National Institutes of Health (NIH), or Newcastle-Ottawa Scale (NOS) according to their study design. Our assessed outcomes were clinical relapse, MRI activity, expanded disability status scale (EDSS), annualized relapse rate (ARR), and progressive multifocal leukoencephalopathy (PML). The statistical analysis was conducted using Review manager software. <h3>Results:</h3> We included 13 studies; two RCTs, one switched single-arm trial, and the rest ten studies were observational. EID for 5–8 weeks was associated with a lower risk of newly enlarging T2 hyperintense lesions than SID (RR= 0.55, 95% CI [0.33, 0.94], p=0.03) and clinical relapse (RR=0.86, 95% CI [0.74, 0.99], p=0.04). However, no difference was detected between EID and SID in Gadolinium-enhancing lesions, ARR, PML, and EDSS. <h3>Conclusions:</h3> Extending dosing intervals up to eight weeks did not diminish the effectiveness of natalizumab therapy, with a lower risk of clinical relapse and developing newly enlarging T2 hyperintense lesions. Well-conducted, longer studies, especially RCTs, are needed to produce more valid results. <b>Disclosure:</b> Mr. Rabea has nothing to disclose. Dr. Belal has nothing to disclose. Dr. Nourelden has nothing to disclose. Mr. El-banna has nothing to disclose. Mr. Khalifa has nothing to disclose. Dr. Mahmoud has nothing to disclose. Mohamed Sayed Zaazouee has nothing to disclose.