The effect of anti-SARS-CoV-2 monoclonal antibody, bamlanivimab, on endogenous immune response to COVID-19 vaccination

As the COVID-19 pandemic evolves, and vaccine rollout progresses, the availability and demand for monoclonal antibodies for the prevention and treatment of SARS-CoV-2 infection are also accelerating. This longitudinal serological study evaluated the magnitude and potency of the endogenous antibody response to COVID-19 vaccination in participants who first received a COVID-19 monoclonal antibody in a prevention study. Over the course of six months, serum samples were collected from the prevention population (nursing home residents and staff) enrolled in the BLAZE-2 clinical trial who had received either bamlanivimab (4200 mg) or placebo. In an unplanned component of this trial, a subset of these participants was subsequently fully vaccinated with two doses of either SpikeVax (Moderna) or Comirnaty (BioNTech/Pfizer) COVID-19 mRNA vaccines, as part of the US vaccination program. This post-hoc analysis assessed the immune response to vaccination for the subset of participants (N=135) without prior SARS-CoV-2 infection. Antibody titers and potency were assessed using three assays against SARS-CoV-2 proteins that bamlanivimab does not significantly bind to, thereby reflecting the endogenous antibody response. All bamlanivimab and placebo participants mounted a robust immune response to full COVID-19 vaccination, irrespective of age, risk-category and vaccine type, with any observed differences unlikely to be clinically meaningful. These findings are pertinent for informing public health policy with results that suggest a complementary role for COVID-19 monoclonal antibodies (mAbs) with COVID-19 vaccines and that the benefit of receiving COVID-19 vaccination at the earliest opportunity outweighs the minimal effect on the endogenous immune response due to prior prophylactic COVID-19 mAb infusion.

Endogenous Antibody Responses to SARS-CoV-2 in Patients With Mild or Moderate COVID-19 Who Received Bamlanivimab Alone or Bamlanivimab and Etesevimab Together

BackgroundNeutralizing monoclonal antibodies (mAbs) to SARS-CoV-2 are clinically efficacious when administered early, decreasing hospitalization and mortality in patients with mild or moderate COVID-19. We investigated the effects of receiving mAbs (bamlanivimab alone and bamlanivimab and etesevimab together) after SARS-CoV-2 infection on the endogenous immune response.MethodsLongitudinal serum samples were collected from patients with mild or moderate COVID-19 in the BLAZE-1 trial who received placebo (n=153), bamlanivimab alone [700 mg (n=100), 2800 mg (n=106), or 7000 mg (n=98)], or bamlanivimab (2800 mg) and etesevimab (2800 mg) together (n=111). A multiplex Luminex serology assay measured antibody titers against SARS-CoV-2 antigens, including SARS-CoV-2 protein variants that evade bamlanivimab or etesevimab binding, and SARS-CoV-2 pseudovirus neutralization assays were performed.ResultsThe antibody response in patients who received placebo or mAbs had a broad specificity. Titer change from baseline against a receptor-binding domain mutant (Spike-RBD E484Q), as well as N-terminal domain (Spike-NTD) and nucleocapsid protein (NCP) epitopes were 1.4 to 4.1 fold lower at day 15-85 in mAb recipients compared with placebo. Neutralizing activity of day 29 sera from bamlanivimab monotherapy cohorts against both spike E484Q and beta variant (B.1.351) were slightly reduced compared with placebo (by a factor of 3.1, p=0.001, and 2.9, p=0.002, respectively). Early viral load correlated with the subsequent antibody titers of the native, unmodified humoral response (p<0.0001 at Day 15, 29, 60 and 85 for full-length spike).ConclusionsPatients with mild or moderate COVID-19 treated with mAbs develop a wide breadth of antigenic responses to SARS-CoV-2. Small reductions in titers and neutralizing activity, potentially due to a decrease in viral load following mAb treatment, suggest minimal impact of mAb treatment on the endogenous immune response.

Biological Hallmarks and New Therapeutic Approaches for the Treatment of PDAC

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the deadliest solid tumors and is estimated to become a leading cause of cancer-related death in coming years. Despite advances in surgical approaches and the emergence of new chemotherapy options, its poor prognosis has not improved in the last decades. The current treatment for PDAC is the combination of cytotoxic chemotherapy agents. However, PDAC shows resistance to many antineoplastic therapies with rapid progression. Although PDAC represents a heterogeneous disease, there are common alterations including oncogenic mutations of KRAS, and the frequent inactivation of different cell cycle regulators including the CDKN2A tumor suppressor gene. An emerging field of investigation focuses on inhibiting the function of proteins that suppress the immune checkpoint PD-1/PD-L1, with activation of the endogenous immune response. To date, all conventional immunotherapies have been less successful in patients with PDAC compared to other tumors. The need for new targets, associated with an extended molecular analysis of tumor samples could give new pharmacological options for the treatment of PDAC. It is, therefore, important to push for a broader molecular approach in PDAC research. Here, we provide a selected summary of emerging strategy options for targeting PDAC using CDK4/6 inhibitors, RAS inhibitors, and new drug combinations with immune checkpoint agents.

Fc-independent neutralization of SARS-CoV-2 by recombinant human monoclonal antibodies

The use of passively-administered neutralizing antibodies is a promising approach for the prevention and treatment of SARS-CoV-2 infection. Antibody-mediated protection may involve immune system recruitment through Fc-dependent activation of effector cells and the complement system. However, the role of Fc-mediated functions in the efficacious in vivo neutralization of SARS-CoV-2 is not yet clear. Delineating the role this process plays in antibody-mediated protection will have a great impact on the design of such therapeutics. Here, the Fc of two highly potent SARS-CoV-2 neutralizing human monoclonal antibodies, targeting distinct domains of the spike, was engineered to abrogate their Fc-dependent functions. The protective activity of these antibodies was tested against lethal SARS-CoV-2 infections in K18-hACE2 transgenic mice, both before or two days post-exposure in comparison to their original, Fc-active antibodies. Antibody treatment with both Fc-variants similarly rescued the mice from death, reduced viral load and prevented signs of morbidity. In addition, surviving animals developed a significant endogenous immune response towards the virus. Taken together, this work provides important insight regarding the contribution of Fc-effector functions in antibody-mediated protection, which should aid in future design of effective antibody-based therapies.

Differential Leukocyte miRNA Responses Following Pan T Cell, Allorecognition and Allosecretome-Based Therapeutics Activation

Background Effective immunomodulation of T cell responses is critical in treating both autoimmune diseases and cancer. Our previous studies have demonstrated that secretomes derived from control or methoxypolyethylene glycol (mPEG) mixed lymphocyte alloactivation assays exerted potent immunomodulatory activity that was mediated by microRNAs (miRNA). In this study, the immunomodulatory effects of biomanufactured miRNA-based allo-secretome therapeutics (SYN, TA1, IA1 and IA2) were compared to Pan T cell activators (PHA and anti-CD3/CD28) and alloactivation (MHC-disparate donors; ± mPEG grafting). The differential effects of these activation strategies on resting PBMC were assessed via T cell differentiation and proliferation as well as the differential expression of multiple miRNA.Results Mitogen-induced PBMC proliferation (average of > 85%) significantly exceed that arising from either allostimulation (~ 30%) or the proinflammatory IA1 secretome product (~ 12%). Consequent to stimulation, the ratio of CD4 to CD8 cells of the resting PBMC (CD4:CD8; 1.7 ± 0.1) decreased in the Pan-T cell, allrecognition and IA1 activated cells (average of 1.1 ± 0.2; 1.2 ± 0.1 and 1.0 ± 0.1). These changes arose consequent to the expansion of both CD4+CD8+ and CD4-CD8- populations and the shrinkage of the CD4 subset relative to the expansion of the CD8 T cells. Most importantly, this study demonstrated that these activation strategies exert profoundly unique effects on the differential expression of miRNA within the treated PBMC and that these 'differential patterns of miRNA expression' are associated with significant differences in cellular differentiation and biological function.Conclusions These findings support the concept that the 'differential pattern of miRNA expression', not a change in a single miRNA, governs the biologic immune response in a 'lock and key' manner. The biomanufacturing of miRNA-enriched secretome biotherapeutics may be a successful approach for producing miRNA cocktails (e.g., TA1 and IA1) that replicate the normal biological 'lock and key' miRNA configuration necessary for the systemic treatment of autoimmune diseases (TA1) or enhancing the endogenous immune response to cancer (IA1).

Influences of Immunocastration on Endocrine Parameters, Growth Performance and Carcass Quality, as Well as on Boar Taint and Penile Injuries

Castration of male pigs without anesthesia is a significant welfare issue. Improvac®, a GnRH vaccine induces an endogenous immune response leading to a decrease in testicular steroids. Consequences of different vaccination schemes on testicular function and carcass quality were evaluated in immunocastrated boars (IC), surgical castrates (SC), and entire males (EM). Therefore, 128 male piglets were assigned to five treatment-groups and a long term follow-up group. IC groups received two vaccinations (V1, V2) with Improvac® at 8 and 12, 12 and 16, or 12 and 18 weeks. Testosterone-concentrations decreased significantly two weeks after V2 in feces and dropped in serum from V2 to slaughter (S) except IC-8/12 without differing significantly. GnRH-binding results indicated the highest values for IC-12/18 animals. While IC-12/16 and IC-12/18 animals showed boar taint compounds below the threshold levels, two IC-8/12 animals had concentrations above the threshold level. Feed-efficiency was higher in EM than in SC with IC in between. In IC compared to EM, a decreasing amount of polyunsaturated-fatty-acids was obvious and GnRH-vaccination reduced penile injuries. The examined vaccination protocols reduce penile injuries, improve feed efficiency and carcass quality, and reliably prevents boar taint, if manufacturer’s recommendations concerning vaccination schedules are applied. Therefore immunocastration offers a reliable, animal friendly alternative to surgical castration.

Ki67 and lymphocytes in the pretherapeutic core biopsy of primary invasive breast cancer: positive markers of therapy response prediction and superior survival

BackgroundCore needle biopsy plays a crucial role as diagnostic tool for BC. Both Ki67 and likely tumor-infiltrating lymphocytes (TILs) in the near future are determining the kind of systemic therapy. The role of TILs in BC is still an issue for clinical research, albeit preliminary results of neoadjuvant and adjuvant clinical studies already now highlight the crucial impact of TILs on therapy response and survival.MethodsEvaluation of related publications (pubmed) and meeting abstracts (ASCO, SABCS).ResultsThe monoclonal antibody Ki67 recognizing a nuclear antigene in proliferating cells is a positive marker of therapy response and superior survival. Endocrine responsive tumors of low proliferation (Ki67 < 14%/11%) respond to tamoxifen, in contrast postmenopausal tumors with higher proliferation respond better to aromatase-inhibitors. Pathological complete response (pCR)-rates increase in tumors with higher proliferation (Ki67 > 19%) vs. tumors with lower proliferation after neoadjuvant chemotherapy (NAC). pCR-rates of up to 60% can be seen in TNBC and HR−, HER2+BC, lower pCR-rates, however, in HR+, HER2− BC. Increased stromal TILs are found in 30% of TNBC and in 19% of HR−, HER2+BC. The percentage of TILs is a significant independent parameter for pCR after NAC. Lymphocyte-predominant BC (LPBC) respond with higher pCR-rates than non-LPBC or tumors without any TILs. Increased TILs in TN and HR−, HER2+ subtypes predict benefit from addition of carboplatin to NAC. TILs are also associated with improved DFS and OS among patients with TNBC and HR−, HER2+ BC. Conversly and interestingly increased TILs in patients with HR+, HER2-(luminal) BC are associated with a 10% higher risk of death per 10% increase of TILs. Interactions between immune system and cancer are complex. The cancer-immunity cycle characterizes these interactions. BC subtypes with higher number of mutations such as TNBC and HR−, HER2+BC are considered to provide a raising number of tumor-associated antigens, thereby capable to build up a higher endogenous immune response. TILs may serve as surrogate marker of both an existing endogenous immune response and the probability to respond to cancer immune therapies. As cancer co-opt immune checkpoint-pathways as a major mechanism of immune resistance, in particular, against cytotoxic T-cells, blockades of checkpoint-pathways by antibodies are one of the goals of the current cancer immunotherapy studies. Therapy studies with antigene-based strategies (vaccines) and antibodies against the immune checkpoints PD-1 and CTLA-4 and their inhibitory pathways in order to enhance cytotoxic T-cell activities against cancer cells with or without chemotherapy are underway.ConclusionsIt can be suggested that the use of multigene expression testing will increase in order to select more clearly primary HR+, HER2− BC patients with intermediate recurrence risk who likely may benefit from chemotherapy. Furthermore Ki67 and the multigene expression test Oncotype DX can act as dynamic markers to avoid cytostatic overtreatment and endocrine undertreatment. A data-derived optimal Ki67 cut point for pCR and DFS as well as OS is currently not feasible. The integration of stromal TILs into the immunohisto-pathological report after their evaluation has been standardized is likely helpful to determine patients who profit by additional carboplatin chemotherapy. Oncologists need an enlarged information about the tumor-microenvironment in future. The preliminary results of current BC immunotherapy studies are encouraging.