Potent Human Monoclonal Antibody Research Articles

Phase 2 study of the efficacy and safety of ponsegromab in patients with cancer cachexia: PROACC-1 study design.

Cancer cachexia is a multifactorial metabolic wasting syndrome characterized by anorexia, unintentional loss of weight involving both skeletal muscle and adipose tissues, progressive functional impairment and reduced survival. Therapeutic strategies for this serious condition are very limited. Growth differentiation factor 15 (GDF-15) is a cytokine that is implicated in cancer cachexia and may represent both a biomarker of cancer cachexia and a potential therapeutic target. Ponsegromab is a potent and selective humanized monoclonal antibody that inhibits GDF-15-mediated signalling. Preclinical and preliminary phase 1 data suggest that ponsegromab-mediated inactivation of circulating GDF-15 may lead to improvement in key characteristics of cachexia. The primary objective of this phase 2 study is to assess the effect of ponsegromab on body weight in patients with cancer, cachexia and elevated GDF-15 concentrations. Secondary objectives include assessing physical activity, physical function, actigraphy, appetite, nausea and vomiting, fatigue and safety. Exploratory objectives include evaluating pharmacokinetics, pharmacodynamics, immunogenicity, lumbar skeletal muscle index and Response Evaluation Criteria in Solid Tumors. Approximately 168 adults with non-small-cell lung, pancreatic or colorectal cancers who have cachexia and elevated GDF-15 concentrations will be randomized in a double-blind, placebo-controlled study (NCT05546476). Participants meeting eligibility criteria will be randomized 1:1:1:1 to one of three dose groups of ponsegromab (100, 200 or 400mg) or matching placebo administered subcutaneously every 4weeks for an initial 12-week treatment period. This is followed by optional open-label treatment with ponsegromab of 400mg administered every 4weeks for up to 1year. The primary endpoint is mean change from baseline in body weight at Week 12. A mixed model for repeated measures followed by a Bayesian Emax model will be used for the primary analysis. Secondary endpoints include physical activity, physical function and actigraphy measured by remote digital sensors; patient-reported appetite-related symptoms assessed by Functional Assessment of Anorexia-Cachexia Therapy subscale scores; anorexia/appetite, nausea and vomiting, and fatigue evaluated according to questions from the Cancer-Related Cachexia Symptom Diary; and incidence of adverse events, safety laboratory tests, vital signs and electrocardiogram abnormalities. Cancer-related cachexia is an area of significant unmet medical need. This study will support the clinical development of ponsegromab as a novel inhibitor of GDF-15, which may ameliorate key pathologies of cancer cachexia to improve patient symptoms, functionality and quality of life. ClinicalTrials.gov ID: NCT05546476.

Fc-Effector-Independent in vivo Activity of a Potent Influenza B Neuraminidase Broadly Neutralizing Antibody.

Influenza B virus (IBV) contributes to substantial influenza-mediated morbidity and mortality, particularly among children. Similar to influenza A viruses (IAV), the hemagglutinin (HA) and neuraminidase (NA) of IBV undergo antigenic drift, necessitating regular reformulation of seasonal influenza vaccines. NA inhibitors, such as oseltamivir, have reduced activity and clinical efficacy against IBV, while M2 channel inhibitors are only effective against IAV, highlighting the need for improved vaccine and therapeutics for the treatment of seasonal IBV infections. We have previously described a potent human monoclonal antibody (hMAb), 1092D4, that is specific for IBV NA and neutralizes a broad range of IBVs. The anti-viral activity of MAbs can include direct mechanisms such as through neutralization and/or Fc-mediated effector functions that are dependent on accessory cells expressing Fc receptors and that could be impacted by potential host-dependent variability. To discern if the in vivo efficacy of 1092D4 was dependent on Fc-effector function, 1092D4 hMAb with reduced ability to bind to Fc receptors (1092D4-LALAPG) was generated and tested. 1092D4-LALAPG had comparable in vitro binding, neutralization, and inhibition of NA activity to 1092D4. 1092D4-LALAPG was effective at protecting against a lethal challenge of IBV in mice. These results suggest that hMAb 1092D4 in vivo activity is minimally dependent on Fc-effector functions, a characteristic that may extend to other hMAbs that have potent NA inhibition activity.

Phase 2 study to assess the efficacy, safety, and tolerability of the GDF-15 inhibitor ponsegromab in patients with cancer cachexia.

TPS12147 Background: Cancer cachexia is a multifactorial metabolic syndrome of wasting characterized by anorexia, unintended weight loss, and decreased skeletal muscle mass, leading to progressive functional impairment, fatigue, diminished quality of life, poor response to anticancer therapy, and reduced survival. One of the biomarkers associated with cancer cachexia is cytokine growth differentiation factor 15 (GDF-15), which is secreted by tumor cells. Preliminary phase 1 data suggest that suppression of GDF-15 may lead to improvement in cachexia-related symptom burden. Ponsegromab is a potent and selective humanized monoclonal antibody that inhibits GDF-15-mediated signaling. The primary objective of this study (NCT05546476) is to assess the effect of ponsegromab on body weight in patients with cancer, cachexia, and elevated circulating GDF-15 concentrations. Secondary objectives include assessing physical activity, gait, anorexia/appetite, nausea and vomiting, fatigue, and safety. Exploratory objectives include evaluating pharmacokinetics, pharmacodynamics, and immunogenicity. Methods: This phase 2 study will enroll approximately 168 adults with non–small cell lung, pancreatic, or colorectal cancers who have cachexia and elevated GDF-15 concentrations. The study will be conducted in 2 parts. The initial 12-week treatment period will be a randomized, double-blind, placebo-controlled study wherein participants who meet eligibility criteria will be randomized 1:1:1:1 to one of 3 dose groups of ponsegromab (administered subcutaneously [SC] every 4 weeks [Q4W]) or placebo. The double-blind period will be followed by optional open-label treatment (OLT) with ponsegromab Q4W SC for up to 1 year. Upon completion of the optional OLT period, there will be a follow-up visit at Week 72. Participants who do not proceed with the optional OLT period will complete the Week 12 visit and a follow-up visit at Week 16. The primary endpoint is the mean change from baseline in body weight at Week 12. A mixed model for repeated measures followed by a Bayesian Emax model will be used for the primary analysis. Secondary endpoints include physical activity and gait measured by remote digital sensors; patient-reported appetite-related symptoms assessed by Functional Assessment of Anorexia-Cachexia Therapy scores; anorexia/appetite, nausea, vomiting, and fatigue evaluated according to questions from the Cancer-related Cachexia Symptom Diary; and incidence of adverse events, safety laboratory tests, vital signs, and electrocardiogram abnormalities. © 2023 American Association for Cancer Research®. Reused with permission. Clinical trial information: NCT05546476 .

Abstract CT054: Phase 2 study to assess the efficacy, safety, and tolerability of the GDF-15 inhibitor ponsegromab in patients with cancer cachexia

Abstract Background: Cancer cachexia is a multifactorial metabolic syndrome of wasting characterized by anorexia, unintended weight loss, and decreased skeletal muscle mass, leading to progressive functional impairment, fatigue, diminished quality of life, poor response to anticancer therapy, and reduced survival. One of the biomarkers associated with cancer cachexia is cytokine growth differentiation factor 15 (GDF-15), which is secreted by tumor cells. Preliminary phase 1 data suggest that suppression of GDF-15 may lead to improvement in cachexia-related symptom burden. Ponsegromab is a potent and selective humanized monoclonal antibody that inhibits GDF-15-mediated signaling. The primary objective of this study (NCT05546476) is to assess the effect of ponsegromab on body weight in patients with cancer, cachexia, and elevated circulating GDF-15 concentrations. Secondary objectives include assessing physical activity, gait, anorexia/appetite, nausea and vomiting, fatigue, and safety. Exploratory objectives include evaluating pharmacokinetics, pharmacodynamics, and immunogenicity. Trial design: This phase 2 study will enroll approximately 168 adults with non-small cell lung, pancreatic, or colorectal cancers who have cachexia and elevated GDF-15 concentrations. The study will be conducted in 2 parts. The initial 12-week treatment period will be a randomized, double-blind, placebo-controlled study wherein participants who meet eligibility criteria will be randomized 1:1:1:1 to one of 3 dose groups of ponsegromab (administered subcutaneously [SC] every 4 weeks [Q4W]) or placebo. The double-blind period will be followed by optional open-label treatment (OLT) with ponsegromab Q4W SC for up to 1 year. Upon completion of the optional OLT period, there will be a follow-up visit at Week 72. Participants who do not proceed with the optional OLT period will complete the Week 12 visit and a follow-up visit at Week 16. The primary endpoint is the mean change from baseline in body weight at Week 12. A mixed model for repeated measures followed by a Bayesian Emax model will be used for the primary analysis. Secondary endpoints include physical activity and gait measured by remote digital sensors; patient-reported appetite-related symptoms assessed by Functional Assessment of Anorexia-Cachexia Therapy scores; anorexia/appetite, nausea, vomiting, and fatigue evaluated according to questions from the Cancer-related Cachexia Symptom Diary; and incidence of adverse events, safety laboratory tests, vital signs, and electrocardiogram abnormalities. ClinicalTrials.gov identifier: NCT05546476 Citation Format: Jeffrey Crawford, Shannon Lubaczewski, Anil Tarachandani, Magdalena A. Harrington, Yan Weng, Ruolun Qiu, Susie M. Collins, Michelle I. Rossulek, James H. Revkin. Phase 2 study to assess the efficacy, safety, and tolerability of the GDF-15 inhibitor ponsegromab in patients with cancer cachexia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT054.

Glycosylated nanoparticle-based PfCSP vaccine confers long-lasting antibody responses and sterile protection in mouse malaria model

The development of an effective and durable vaccine remains a central goal in the fight against malaria. Circumsporozoite protein (CSP) is the major surface protein of sporozoites and the target of the only licensed Plasmodium falciparum (Pf) malaria vaccine, RTS,S/AS01. However, vaccine efficacy is low and short-lived, highlighting the need for a second-generation vaccine with superior efficacy and durability. Here, we report a Helicobacter pylori apoferritin-based nanoparticle immunogen that elicits strong B cell responses against PfCSP epitopes that are targeted by the most potent human monoclonal antibodies. Glycan engineering of the scaffold and fusion of an exogenous T cell epitope enhanced the anti-PfCSP B cell response eliciting strong, long-lived and protective humoral immunity in mice. Our study highlights the power of rational vaccine design to generate a highly efficacious second-generation anti-infective malaria vaccine candidate and provides the basis for its further development.

Neutralization Epitopes in Trimer and Pentamer Complexes Recognized by Potent Cytomegalovirus-Neutralizing Human Monoclonal Antibodies.

Human cytomegalovirus (HCMV) infects 36% to almost 100% of adults and causes severe complications only in immunocompromised individuals. HCMV viral surface trimeric (gH/gL/gO) and pentameric (gH/gL/UL128/UL130/UL131A) complexes play important roles in HCMV infection and tropism. Here, we isolated and identified a total of four neutralizing monoclonal antibodies (MAbs) derived from HCMV-seropositive blood donors. Based on their reactivity to HCMV trimer and pentamer, these MAbs can be divided into two groups. MAbs PC0012, PC0014, and PC0035 in group 1 bind both trimer and pentamer and neutralize CMV by interfering with the postattachment steps of CMV entering into cells. These three antibodies recognize antigenic epitopes clustered in a similar area, which are overlapped by the epitope recognized by the known neutralizing antibody MSL-109. MAb PC0034 in group 2 binds only to pentamer and neutralizes CMV by blocking the binding of pentamer to cells. Epitope mapping using pentamer mutants showed that amino acid T94 of the subunit UL128 and K27 of UL131A on the pentamer are key epitope-associated residues recognized by PC0034. This study provides new evidence and insight information on the importance of the development of the CMV pentamer as a CMV vaccine. In addition, these newly identified potent CMV MAbs can be attractive candidates for development as antibody therapeutics for the prevention and treatment of HCMV infection. IMPORTANCE The majority of the global population is infected with HCMV, but severe complications occur only in immunocompromised individuals. In addition, CMV infection is a major cause of birth defects in newborns. Currently, there are still no approved prophylactic vaccines or therapeutic monoclonal antibodies (MAbs) for clinical use against HCMV infection. This study identified and characterized a panel of four neutralizing MAbs targeting the HCMV pentamer complex with specific aims to identify a key protein(s) and antigenic epitopes in the HCMV pentamer complex. The study also explored the mechanism by which these newly identified antibodies neutralize HCMV in order to design better HCMV vaccines focusing on the pentamer and to provide attractive candidates for the development of effective cocktail therapeutics for the prevention and treatment of HCMV infection.

Potent monoclonal antibodies neutralize Omicron sublineages and other SARS-CoV-2 variants.

The emergence and global spread of the SARS-CoV-2 Omicron variants, which carry an unprecedented number of mutations, raise serious concerns due to the reduced efficacy of current vaccines and resistance to therapeutic antibodies. Here, we report the generation and characterization of two potent human monoclonal antibodies, NA8 and NE12, against the receptor-binding domain of the SARS-CoV-2 spike protein. NA8 interacts with a highly conserved region and has a breadth of neutralization with picomolar potency against the Beta variant and the Omicron BA.1 and BA.2 sublineages and nanomolar potency against BA.2.12.1 and BA.4. Combination of NA8 and NE12 retains potent neutralizing activity against the major SARS-CoV-2 variants of concern. Cryo-EM analysis provides the structural basis for the broad and complementary neutralizing activity of these two antibodies. We confirm the in vivo protective and therapeutic efficacies of NA8 and NE12 in the hamster model. These results show that broad and potent human antibodies can overcome the continuous immune escape of evolving SARS-CoV-2 variants.

2D NMR Analysis as a Sensitive Tool for Evaluating the Higher-Order Structural Integrity of Monoclonal Antibody against COVID-19.

The higher-order structure (HOS) of protein therapeutics has been confirmed as a critical quality parameter. In this study, we compared 2D 1H-13C ALSOFAST-HMQC NMR spectra with immunochemical ELISA-based analysis to evaluate their sensitivity in assessing the HOS of a potent human monoclonal antibody (mAb) for the treatment of coronavirus disease 2019 (COVID-19). The study confirmed that the methyl region of the 2D 1H-13C NMR spectrum is sensitive to changes in the secondary and tertiary structure of the mAb, more than ELISA immunoassay. Because of its highly detailed level of characterization (i.e., many 1H-13C cross-peaks are used for statistical comparability), the NMR technique also provided a more informative outcome for the product characterization of biopharmaceuticals. This NMR approach represents a powerful tool in assessing the overall higher-order structural integrity of mAb as an alternative to conventional immunoassays.

Feasibility Studies of Nebulized SARS-CoV-2 Neutralizing Antibody in Mice and Cynomolgus Monkeys

PurposeNeutralizing antibodies, administrated through intravenous infusion, have shown to be highly efficacious in treating mild and moderate COVID-19 caused by SARS-CoV-2 infection in the lung. However, antibodies do not transport across the plasma-lung barrier efficiently, and up to 100 mg/kg dose was used in human causing significant supply and cost burdens. This study was to explore the feasibility of nebulized antibodies inhalation delivery as an alternative route.MethodsHB27, a potent RBD-specific humanized monoclonal antibody (Zhu et al. in National Sci Rev. 8:nwaa297, 2020), showed excellent protection against SARS-CoV-2 in animal model and good safety profile in clinical studies. The pharmacokinetics and preliminary safety of HB27 administrated through the respiratory tract were studied in mice and cynomolgus monkeys here.ResultsAt a single 5 mg/kg dose, the peak HB27 concentration in mice pulmonary epithelial lining fluid (ELF) reached 857.8 μg/mL, 670-fold higher than the PRNT90 value of 1.28 μg/mL, and maintained above PRNT90 over 240 h. In contrast, when administrated by intravenous injection at a 5 mg/kg dose, the antibody concentrations in mice ELF were below PRNT90 value throughout, and were about 50-fold lower than that in the serum. In cynomolgus monkeys administrated with a single dose through inhalation, the antibody concentration in ELF remained high within 3 days. No drug-related safety concerns were observed in the studies.ConclusionsThe study demonstrated that nebulized neutralizing antibody delivery though inhalation could be a more efficient and efficacious alternative approach for treating COVID-19 and other respiratory infectious diseases, and warrants further evaluation in clinical studies.

A phase 1/2 multicenter investigator-initiated trial of DKN-01 as monotherapy or in combination with docetaxel for the treatment of metastatic castration-resistant prostate cancer (mCRPC).

5048 Background: Dickkopf-1 (DKK1) is a secreted Wnt signaling modulator that is upregulated in prostate cancers with low androgen receptor (AR) expression and co-occurring mutations in Wnt signaling family genes. DKN-01, a potent humanized monoclonal antibody (IgG4) with neutralizing activity against DKK1, delays prostate cancer growth in pre-clinical DKK1-expressing models in an NK cell dependent manner. These data provided the rationale for a prospective clinical trial testing DKN-01 in patients with mCRPC and elevated DKK1. Here, we report the safety and efficacy results of the phase 1 dose escalation cohorts. Methods: This is an investigator-initiated parallel-arm non-randomized phase 1/2 clinical trial testing DKN-01 alone or in combination with docetaxel 75 mg/m2 for men with mCRPC who progressed on ≥1 AR signaling inhibitor. Eligible patients who had progressed on or were intolerant of docetaxel were assigned to the monotherapy cohort whereas taxane-naïve patients were assigned to the DKN-01 plus docetaxel combination cohort. DKK1 status was determined by RNA in-situ expression. The primary endpoint of the phase 1 dose escalation cohorts was safety, characterized by dose-limiting toxicity (DLT). A secondary endpoint of the study was to correlate anti-tumor activity, DKK1 expression (cutoff H-score ≥ 1), and clinical evidence of aggressive variant prostate cancer (AVPC). Results: 13 pts were enrolled in the completed phase 1 portion of this study – 7 patients in the monotherapy cohort and 6 patients in the combination cohort. No DLTs were observed at DKN-01 300mg or 600mg dose levels as monotherapy or in combination with docetaxel. No treatment-related serious adverse events occurred in either cohort. A best overall response of stable disease occurred in 2 out of 7 patients in the monotherapy cohort. In the combination cohort, all 5 evaluable patients had a partial response (PR) – 3 confirmed and 2 unconfirmed. All evaluable combination patients had ≥ 50% reduction in either PSA or CEA. Confirmed PRs in the combination cohort were observed in both DKK1 low (DKK1 H-score < 1) and high expressing tumors (H-score ≥1), including in 2 out of 3 patients with AVPC. Conclusions: DKN-01 600mg was well tolerated and selected as the recommended phase 2 dose as monotherapy and in combination with docetaxel. DKN-01 in combination with docetaxel showed promising clinical activity in prostate cancers regardless of DKK1 expression and was particularly promising in patients with AVPC. Further accrual into the phase 2 portion of this study is ongoing alongside preclinical and correlative studies aiming to investigate the mechanism of action of this combination therapeutic strategy. Clinical trial information: NCT03837353.

A potent human monoclonal antibody with pan-neutralizing activities directly dislocates S trimer of SARS-CoV-2 through binding both up and down forms of RBD

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel coronavirus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor-binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo. Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.

The light chain of the L9 antibody is critical for binding circumsporozoite protein minor repeats and preventing malaria.

L9 is a potent human monoclonal antibody (mAb) that preferentially binds two adjacent NVDP minor repeats and cross-reacts with NANP major repeats of the Plasmodium falciparum circumsporozoite protein (PfCSP) on malaria-infective sporozoites. Understanding this mAb's ontogeny and mechanisms of binding PfCSP will facilitate vaccine development. Here, we isolate mAbs clonally related to L9 and show that this B cell lineage has baseline NVDP affinity and evolves to acquire NANP reactivity. Pairing the L9 kappa light chain (L9κ) with clonally related heavy chains results in chimeric mAbs that cross-link two NVDPs, cross-react with NANP, and more potently neutralize sporozoites invivo compared with their original light chain. Structural analyses reveal that the chimeric mAbs bound minor repeats in a type-1 β-turn seen in other repeat-specific antibodies. These data highlight the importance of L9κ in binding NVDP on PfCSP to neutralize sporozoites and suggest that PfCSP-based immunogens might be improved by presenting ≥2 NVDPs.

Diabetic Ketoacidosis Precipitated by Pembrolizumab: A Case Report on the Challenges of Long-term Management

Introduction: Pembrolizumab (Keytruda®) is a potent and selective humanized monoclonal immunoglobulin antibody that blocks programmed cell death-1 on T cells, augmenting the antitumor immune response. Pembrolizumab is an approved adjuvant therapy for treating metastatic melanoma. Clinical Findings: A 75-year-old man with metastatic melanoma developed diabetic ketoacidosis before receiving a sixth cycle of pembrolizumab. Clinical Course: He received intravenous insulin, fluids, and electrolyte repletion per the diabetic ketoacidosis protocol. He presented again to the emergency room with profound hyperglycemia 1 week after discharge. Following a second round of treatment, his home insulin regimen was titrated for better glycemic control, and pembrolizumab was discontinued. Conclusions: As cases of diabetes associated with immune checkpoint inhibitor therapy are increasingly reported, challenges may include adequately managing diabetes long-term, preventing diabetic ketoacidosis, and discontinuing pembrolizumab due to immune-related adverse effects.

Structures and therapeutic potential of anti-RBD human monoclonal antibodies against SARS-CoV-2.

Background: Administration of potent anti-receptor-binding domain (RBD) monoclonal antibodies has been shown to curtail viral shedding and reduce hospitalization in patients with SARS-CoV-2 infection. However, the structure-function analysis of potent human anti-RBD monoclonal antibodies and its links to the formulation of antibody cocktails remains largely elusive.Methods: Previously, we isolated a panel of neutralizing anti-RBD monoclonal antibodies from convalescent patients and showed their neutralization efficacy in vitro. Here, we elucidate the mechanism of action of antibodies and dissect antibodies at the epitope level, which leads to a formation of a potent antibody cocktail.Results: We found that representative antibodies which target non-overlapping epitopes are effective against wild type virus and recently emerging variants of concern, whilst being encoded by antibody genes with few somatic mutations. Neutralization is associated with the inhibition of binding of viral RBD to ACE2 and possibly of the subsequent fusion process. Structural analysis of representative antibodies, by cryo-electron microscopy and crystallography, reveals that they have some unique aspects that are of potential value while sharing some features in common with previously reported neutralizing monoclonal antibodies. For instance, one has a common VH 3-53 public variable region yet is unusually resilient to mutation at residue 501 of the RBD. We evaluate the in vivo efficacy of an antibody cocktail consisting of two potent non-competing anti-RBD antibodies in a Syrian hamster model. We demonstrate that the cocktail prevents weight loss, reduces lung viral load and attenuates pulmonary inflammation in hamsters in both prophylactic and therapeutic settings. Although neutralization of one of these antibodies is abrogated by the mutations of variant B.1.351, it is also possible to produce a bi-valent cocktail of antibodies both of which are resilient to variants B.1.1.7, B.1.351 and B.1.617.2.Conclusions: These findings support the up-to-date and rational design of an anti-RBD antibody cocktail as a therapeutic candidate against COVID-19.

Clonal Wars: Monoclonal Antibodies Against Infectious Pathogens.

Monoclonal antibodies are coming of age as powerful tools for the prevention of infectious diseases. In recent years, the rate of antibody discovery has accelerated, and the coronavirus disease 2019 (COVID-19) pandemic has shone a spotlight on the role of these antibodies in combating pathogens. However, questions remain about the utility of monoclonal antibodies, especially when effective vaccines are also available. In this article, I discuss the role of monoclonal antibodies and briefly describe the effort to identify potent human monoclonal antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including our study on bispecific antibodies that neutralize SARS-CoV-2 variants of concern.

Exceptionally potent human monoclonal antibodies are effective for prophylaxis and treatment of tetanus in mice.

We used human monoclonal antibodies (humAbs) to study the mechanism of neuron intoxication by tetanus neurotoxin and to evaluate these antibodies as a safe preventive and therapeutic substitute for hyperimmune sera to treat tetanus in mice. By screening memory B cells from immune donors, we selected 2 tetanus neurotoxin-specific mAbs with exceptionally high neutralizing activities and extensively characterized them both structurally and functionally. We found that these antibodies interfered with the binding and translocation of the neurotoxin into neurons by interacting with 2 epitopes, whose identification pinpoints crucial events in the cellular pathogenesis of tetanus. Our observations explain the neutralization ability of these antibodies, which we found to be exceptionally potent in preventing experimental tetanus when injected into mice long before the toxin. Moreover, their Fab derivatives neutralized tetanus neurotoxin in post-exposure experiments, suggesting their potential for therapeutic use via intrathecal injection. As such, we believe these humAbs, as well as their Fab derivatives, meet the requirements to be considered for prophylactic and therapeutic use in human tetanus and are ready for clinical trials.

Cemiplimab in advanced cutaneous squamous cell carcinoma.

Cemiplimab, a high-affinity, highly potent human monoclonal antibody that binds to the programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) receptor, is the only drug to attain Food and Drug Administration (FDA) approval and marketing authorization from the European Commission for use in patients with metastatic and locally advanced cutaneous squamous cell carcinoma (CSCC) who are not candidates for curative surgery or curative radiation therapy as a first- or later-line treatment. In pivotal phase II clinical testing, cemiplimab showed rapid and substantial antitumor efficacy and acceptable safety. This systematic review was aimed at evaluating the efficacy and safety of cemiplimab in patients with advanced CSCC. To this end, I reviewed EMBASE, MEDLINE, PubMed, and clinical trial registries/databases by using the following keywords alone or in combination: "cemiplimab," "Libtayo," "cutaneous squamous cell carcinoma," "REGN2810," and "SER439684." Cemiplimab showed clinical efficacy and considerable safety and was associated with low rates of treatment discontinuation (7%) and death (3%). However, the current recommendation is primarily based on only phase II clinical testing due to the absence of an approved comparator agent.

1696TiP Phase Ib study to assess the effect of PF-06946860 on appetite following subcutaneous administration in patients with anorexia and advanced cancer

Cachexia is a hypermetabolic multifactorial syndrome characterized by anorexia and loss of weight and skeletal muscle, leading to fatigue, functional impairment, increased treatment-related toxicity, poor quality of life, and reduced survival. Anorexia is a central component of the cachectic phenotype and may be primarily mediated by growth differentiation factor 15 (GDF-15). Neutralization of GDF-15 may improve anorexia and other cancer cachexia-related clinical outcomes. PF-06946860 is a highly potent and selective humanized monoclonal antibody directed against GDF-15.

A broad-spectrum and highly potent human monoclonal antibody cocktail for rabies prophylaxis.

Post-exposure prophylaxis (PEP) is highly effective in preventing disease progression of rabies when used in timely and appropriate manner. The key treatment for PEP is infiltration of rabies immune globulin (RIG) into lesion site after bite exposure, besides wound care and vaccination. Unfortunately, however, RIG is expensive and its supply is limited. Currently, several anti-rabies virus monoclonal antibody (mAb) products are under development as alternatives to RIG, and two recently received regulatory approval in India. In this study, fully human mAbs that recognize different rabies virus glycoprotein conformational antigenic site (II and III) were created from peripheral blood mononuclear cells of heathy vaccinated subjects. These mAbs neutralized a diverse range of lyssavirus types. As at least two anti-rabies virus mAbs are recommended for use in human PEP to ensure broad coverage against diverse lyssaviruses and to minimize possible escape variants, two most potent mAbs, NP-19-9 and 11B6, were selected to be used as cocktail treatment. These two mAbs were broadly reactive to different types of lyssaviruses isolates, and were shown to have no interference with each other. These results suggest that NP-19-9 and 11B6 are potent candidates to be used for PEP, suggesting further studies involving clinical studies in human.

A phase II open label, single arm study to evaluate the efficacy of pembrolizumab for leukoplakia.

TPS10606 Background: The presence of pre-cancerous oral lesions such as leukoplakia or erythroleukoplakia are known risk factors for the development of squamous cell carcinoma of the head and neck (SCCHN), however preventative agents have not yet shown clinical benefit. The risk of malignant transformation varies but has been quoted as high as 36% in some studies. While the primary mode of treatment of these lesions is largely surgical, recurrence rates are high. Pembrolizumab is a potent and selective humanized monoclonal antibody that is designed to directly block the interaction between PD-1 and PD-L1 (as well as PD-L2) that is currently FDA-approved for treatment of SCCHN. We have hypothesized that the treatment of oral premalignant lesions with pembrolizumab would be an effective and well-tolerated strategy to prevent transformation to invasive cancer. Methods: This study is an open-label, phase II study that will accrue 26 patients with leukoplakia, erythroleukoplakia, or proliferative verrucous leukoplakia with documented moderate to severe dysplasia or carcinoma in situ to be treated with pembrolizumab 200mg every 3 weeks for a total of 6 months. Patients must have visible and measurable lesions that will be both photographed and measured in two dimensions at each visit from the start of treatment until 12 months post-enrollment. Biopsies will be required at diagnosis and following the final treatment, with an optional biopsy following cycle 2 and at progression of disease. Major exclusion criteria include patients with mild dysplasia or hyperplasia, prior chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks of Day 1 of study, or patients with a known additional malignancy that is active. Patients will also be excluded if they have received anti-PD-1, anti-PD-L1 or anti-PD-L2 treatments in the past. The primary objective is clinical response rate at 6 months, and will be quantified as the percentage of patients with a complete response (CR) and partial response (PR) at 6 months. A CR is defined as complete resolution by visual inspection for 4 weeks of more and a PR is defined as 50% or greater reduction of the product of the 2 dimensions of a single lesions or the sum of all lesions. Progressive disease (PD) is defined as unequivocal increase (greater than or equal to 5mm in one dimension and greater than 20% increase) or the development of new lesions. Secondary objectives will include histologic response rate at 6 months, change in clinical impression based on photographs, clinical response rate at 9 and 12 months, and toxicity. Additional exploratory objectives will include PD-L1 expression in leukoplakia lesions as well as p16 expression, presence of tumor infiltrating lymphocytes, and immunohistochemical as well as RNA sequencing gene expression profiling which may allow for the identification of novel biomarkers. Enrollment began in June 2019 and is ongoing. Clinical trial information: NCT03603223 .