ABSTRACT
Background: Patients with hematologic conditions have a high mortality rate when infected with SARS-CoV-2 (Williamson, Nature 2020). Protection of this group from severe COVID-19 is therefore important. However, according to available vaccination guidelines, one should consider to postpone vaccination of patients on or early after chemotherapy, hematopoietic progenitor cell transplantation (HCT) or with graft versus host disease, because of anticipated poor efficacy. Based on previous (non-COVID-19) vaccination studies among hematology patients, we hypothesized that a significant group of patients may acquire sufficient protection following COVID-19 vaccination, despite disease and therapy related immunodeficiencies. Methods: We conducted a prospective cohort study with 17 cohorts of hematology patients of particular risk for severe COVID-19 who are considered to have no or limited benefit from vaccination. We evaluated humoral immune responses following 2 doses (28 days apart) of the mRNA-1273 vaccine (Moderna/Spikevax) in 722 patients, at baseline and 28 days after each vaccination as SARS-COV-2 S1- (spike)-specific serum IgG antibody concentrations by bead-based multiplex immune assay. The threshold for adequate antibody response is set at ≥300 binding antibody units (BAU)/ml according to the international WHO standard, and is associated with virus plaque reducing neutralization test titers of ≥40 PRNT 50. This study is registered as EudraCT 2021-001072-41, NL76768.029.21. Results: Patient cohorts and corresponding vaccine responses are depicted in Table 1. Vaccine efficacy, as measured by antibody concentration, 4 weeks after the 2nd mRNA-1273 vaccination was available for 691 out of 722 participants. The majority of patients (389/691;56%) obtained an S1 antibody titer that is considered adequate (≥300 BAU/ml). Twenty-nine percent of patients (198/691) did not seroconvert (S1 antibody titer <10 BAU/ml), while the remaining 15% (104/691) did seroconvert but not to sufficient levels (10-300 BAU/ml). Adequate responses were observed in the majority of patients with sickle cell disease using hydroxyurea, chronic myeloid leukemia (CML) receiving tyrosine kinase inhibitor therapy, acute myeloid leukemia (AML) on or early after high dose chemotherapy, patients with myeloproliferative disorders on ruxolitinib, patients with multiple myeloma (MM), including those on daratumumab and those early after high-dose melphalan and autologous HCT, patients with untreated chronic lymphocytic leukemia (CLL), and patients with chronic GvHD. Insufficient or absent antibody responses were observed in the majority of AML patients receiving hypomethylating agents, CLL patients on ibrutinib, patients with B-cell non-Hodgkin's Lymphoma (NHL) during or shortly after rituximab-chemotherapy or following BEAM chemotherapy and autologous HCT, allogeneic HCT recipients <6 months after transplantation, and CAR-T cell therapy recipients. However, even in these low-responder groups considerable numbers of patients did mount sufficient antibody titers. In others, titers increased after each of both vaccinations, suggesting that booster vaccination may enhance antibody titers to sufficient levels (Figure 1). Conclusion: Vaccination with mRNA-1273 had significant efficacy in severely immunocompromised hematology patients. Adequate humoral immune responses after two dose vaccination were reached in the majority of patients receiving therapy for sickle cell disease, MPD, MM, CML and AML, in patients early after HCT and in patients with GvHD. We are currently evaluating clinical and immunologic parameters that correlate with sufficient antibody responses, pseudovirus neutralization and SARS-COV-2-specific B and T cell numbers, phenotype and function. Per study design, all participants with absent or insufficient antibody responses (<300 BAU/ml) will receive a booster vaccination 5 months after initial vaccination, and antibody responses to booster vaccinations will be presented as well. Unlike currently available guidelines, COVID-19 vaccination should not be postponed. Moreover, as antibody titers increased after each of both vaccinations, booster vaccination of patients with absent or insufficient antibody responses seems warranted. (Figure Presented) .
ABSTRACT
Background: Patients with cancer have an increased risk of complications from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Vaccination is recommended, but the impact of chemotherapy and immunotherapy on immunogenicity and safety is still unclear. Methods: This prospective multicenter non-inferiority trial comprises four cohorts: individuals without cancer (A) and patients with solid tumors who were treated with immunotherapy (B), chemotherapy (C) or chemo-immunotherapy (D). Participants received two mRNA-1273 vaccinations 28 days apart. The primary endpoint was SARS-CoV-2 Spike S1-specific IgG serum antibody response, defined as >10 binding antibody units (BAU)/ml 28 days after the second vaccination. We also assessed the virus neutralizing capacity of these antibodies, SARS-CoV-2 Spike-specific interferon-gamma T cell response, and adverse events. Results: Of the 791 participants enrolled, 743 were evaluable for the primary endpoint in cohort A (n=240), B (n=131), C (n=229) and D (n=143). A SARS-CoV-2-binding antibody response was found in 100%, 99.3%, 97.4%, and 100% of the participants in cohorts A, B, C, and D, respectively. To discriminate between suboptimal and adequate responders, we defined a cut-off level at 300 BAU/ml, based on neutralizing capacity. The antibody response was considered adequate after the first vaccination in 66.0%, 37.1%, 32.5%, and 33.3% of the participants in cohorts A, B, C, and D, respectively. This raised 28 days after the second vaccination to respectively 99.6%, 93.1%, 83.8%, and 88.8% in cohorts A, B, C, and D. Spike-specific T cell responses were detected in 46.7% of suboptimal and non-responders. No new safety signals were observed. Conclusions: mRNA-1273 vaccination is safe in the patient populations studied. For each cohort, the proportion of patients with a SARS-CoV-2-binding antibody response after two vaccinations is non-inferior compared to individuals without cancer. However, a significant minority lacks an adequate response. Most patients have an antibody concentration increase after the second vaccination. Therefore, an additional booster may turn inadequate into adequate responders. Clinical trial identification: NCT04715438. Legal entity responsible for the study: University Medical Center Groningen, the Netherlands. Funding: ZonMw, The Netherlands Organisation for Health Research and Development. Disclosure: All authors have declared no conflicts of interest.
ABSTRACT
The spike protein of the pandemic human corona virus is essential for its entry into human cells. In fact, most neutralizing antibodies against Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) are directed against the Virus-surface exposed spike protein, making it the antigen of choice for use in vaccines and diagnostic tests. In the current pandemic context, global demand for spike proteins has rapidly increased and could exceed hundreds of grams to kilograms annually. Coronavirus spikes are large heavily glycosylated homo-trimeric complexes, with inherent instability. The poor manufacturability now threatens the availability of these proteins for vaccines and diagnostic tests. Here, we outline scalable, Good Manufacturing Practice (GMP) compliant, and chemically defined processes for the production of two cell-secreted stabilized forms of the trimeric spike proteins (Wuhan and D614G variant). The processes are chemically defined and based on clonal suspension-CHO cell populations and on protein purification via a two-step scalable downstream process. The trimeric conformation was confirmed using electron microscopy and HPLC analysis. Binding to susceptible cells was shown using a virus-inhibition assay. The diagnostic sensitivity and specificity for detection of serum SARS-CoV-2-specific-immunoglobulin molecules was found to exceed that of spike fragments (Spike subunit-1, S1 and Receptor Binding Domain, RBD). The process described here will enable production of sufficient high-quality trimeric spike protein to meet the global demand for SARS-CoV-2 diagnostic tests and potentially vaccines.