Efficacy of a Third BNT162b2 mRNA COVID-19 Vaccine Dose in Patients with CLL who Failed Standard Two-dose Vaccination

Delayed but successful development of immune memory against SARS-COV-2 after B cell-depleting monotherapy

PURPOSE

Patients receiving CD20-directed therapies are known to insufficiently develop neutralizing antibody titers against SARS-COV-2 after two vaccinations. We investigated the impact of a third and fourth vaccination, possibly deriving predictive factors.

METHODS

In a monocentric, prospective, non-interventional observational study patients who had received at least one administration of a monoclonal CD20 antibody (mCD20Ab) within 9 months prior to vaccination were included to receive mRNA-based third vaccination. SARS-COV-2 IgG titer was determined before and four weeks after immunisation. Patients without adequate humoral immune response proceeded to a fourth vaccination. Furthermore, tolerability and prespecified potentially influencing factors such as age, baseline lymphocyte counts and others were analysed.

RESULTS

Twenty-four patients were included and vaccination was well tolerated. Quantitative analysis of humoral response four weeks after third vaccination revealed a significant increase which, however, did not translate into a clinically relevant seroconversion rate. In the subgroup analysis, patients older than 65 years and mCD20Ab therapy longer than 6 months ago benefited. All evaluable patients on mCD20Ab monotherapy (n = 7) showed an immediate or delayed immune response after third vaccination, while all non-responders (n = 7) were on combination therapy. Clinical parameters such as lymphocyte count, immunoglobulin status and others did not appear to have any influence.

CONCLUSION

An interval of at least 6 months after the last mCD20Ab administration and mCD20Ab monotherapy appears to be favorable for humoral immune response to third vaccination. Furthermore, patients can be reassured that delayed immune responses are possible. Future studies should therefore also investigate seroconversion at later time points.

A 3-week pause versus continued Bruton tyrosine kinase inhibitor use during COVID-19 vaccination in individuals with chronic lymphocytic leukaemia (IMPROVE trial): a randomised, open-label, superiority trial

BACKGROUND

Chronic lymphocytic leukaemia is the commonest leukaemia and is associated with profound immunosuppression. Bruton tyrosine kinase inhibitors (BTKi) have revolutionised chronic lymphocytic leukaemia management; however, therapy impairs vaccine-induced immunity. We evaluated whether a 3-week pause of BTKi treatment improved spike protein receptor binding domain (RBD) immunity to SARS-CoV-2 booster vaccination while maintaining disease control.

METHODS

We performed an open-label, two-arm, parallel-group, randomised trial in secondary-care haematology clinics in 11 UK hospitals. Participants aged 18 years or older, diagnosed with chronic lymphocytic leukaemia, and currently taking BTKi therapy (frontline or relapsed setting) for at least 12 months were eligible. Participants were randomly allocated (1:1, by a centralised computer randomisation program, stratified by BTKi therapy line) to pause BTKi for 3 weeks, starting 6 days before their SARS-CoV-2 vaccination booster date, or to continue therapy as usual. Neither participants nor clinical staff were blinded but laboratory staff were. Intramuscular injection of either original BA.1 or original BA.4/5 bivalent mRNA vaccine (50 μg mRNA-1273 or 30 μg BNT162b2), or 5 μg protein-based Vidprevtyn Beta (Sanofi Pasteur, Lyon, France) were received according to the national vaccination programme schedule. The primary outcome measure was anti-spike-RBD-specific antibody titre 3 weeks after vaccination and analysis performed by intention to treat (as randomly allocated, irrespective of compliance) following trial completion. This trial is registered with ISRCTN, 14197181, and has been completed.

FINDINGS

Between Oct 10, 2022, and June 8, 2023, 99 individuals (71 [72%] male and 28 [28%] female, with 89 [90%] of White ethnicity) were randomly allocated to groups pausing (n=50 [51%]) or continuing (n=49 [49%]) their BTKi therapy, and followed up for 12 weeks. At 3 weeks after vaccination, the geometric mean anti-spike-RBD-specific antibody titre was 218·8 U/mL (SD 122·9) in the continue group and 153·4 U/mL (103·2) in the pause group, with geometric mean ratio 1·104 (95% CI 0·565-2·158, p=0·77) using a mixed-effects model. The only serious adverse event during the 12-week follow-up was the death of one participant in the pause group due to COVID-19 infection 2 months after randomisation.

INTERPRETATION

Although the study was slightly underpowered, the results suggest that pausing BTKi around the time of vaccination is not beneficial for immunity and should not be recommended in clinical practice.

FUNDING

National Institute for Health and Care Research.

BNT162b2 mRNA vaccination affects the gut microbiome composition of patients with follicular lymphoma and chronic lymphocytic leukemia

BACKGROUND

In both chronic lymphatic leukemia (CLL) and follicular lymphoma (FL) immunotherapy determines B-depletion that leads to temporary suppression of humoral immunity, which is clinically relevant especially during the COVID-19 pandemic, when most patients in the first wave received the BNT162b2 vaccine during anti-neoplastic treatment.

METHODS

To capture changes in the immunome and microbiome composition in CLL and FL patients upon mRNA-based vaccination, we designed a prospective, longitudinal study to profile both the humoral and the cellular response after exposure to the BNT162b2 COVID-19 vaccine.

RESULTS

In both CLL patients and FL patients, the second and third administrations of the BNT162b2 vaccine increased the titer of specific antibodies against SARS-CoV-2. In FL patients, vaccination induced expansion of central memory CD8 + CD57dim CD279 + T cells and reduction of the neutrophil subset myeloid 1 (CD14-CD15+CD16dimCD64+CD33-CD38+PDL1+HLA-DR-); in both cohorts, CD45RA + CD27 + CD279 + NK cells were expanded after a full cycle of vaccination. After vaccination, the genera Collinsella, Gemmiger, Lachnospiraceae, Blautia, Ruminococcus and Lactobacillus increased in both CLL patients and FL patients, whereas Faecalibacterium, Enterobacteriacae, and Enterococcus decreased. Multivariate analysis failed to identify factors associated with changes in microbiome communities among the CLL and FL cohorts, considering age, sex, exposure to anti-CD20 therapy and disease activity. Only in FL patients, alpha diversity was negatively correlated with neutrophil subsets myeloid 1 e 5 at baseline and positively correlated with neutrophil subset 6 after vaccination. PICRUSt2 analysis showed how microbiome can also affect the host health promoting chronic inflammation. The L-lysine biosynthesis pathway was more represented in CLL patients, whereas the L-valine degradation pathway and the anaerobic degradation of purine nucleobases were overrepresented in the FL cohort.

CONCLUSIONS

Taken together, our findings reveal the effect of the BNT162b2 vaccine in shaping the microbiome composition in CLL and FL patients, despite receiving treatment for their underlying active disease, and highlight the importance of a comprehensive analysis of the immunome and microbiome profiling to understand immune function in these cohorts of patients.

Safety of two-dose schedule of COVID-19 adsorbed inactivated vaccine (CoronaVac; Sinovac/Butantan) and heterologous additional doses of mRNA BNT162b2 (Pfizer/BioNTech) in immunocompromised and immunocompetent individuals

Immunocompromised individuals were considered high-risk for severe disease due to SARS COV-2 infection. This study aimed to describe the safety of two doses of COVID-19 adsorbed inactivated vaccine (CoronaVac; Sinovac/Butantan), followed by additional doses of mRNA BNT162b2 (Pfizer/BioNTech) in immunocompromised (IC) adults, compared to immunocompetent/healthy (H) individuals. This phase 4, multicenter, open label study included solid organ transplant and hematopoietic stem cell transplant recipients, cancer patients and people with inborn errors of immunity with defects in antibody production, rheumatic, end-stage chronic kidney or liver disease, who were enrolled in the IC group. Participants received two doses of CoronaVac and additional doses of mRNA BNT162b2. Adverse reactions (AR) data were collected within seven days after each vaccination. Serious adverse events and of special interest (AESI) were monitored throughout the study. We included 241 immunocompromised and 100 immunocompetent subjects. Arthralgia, fatigue, myalgia, and nausea were more frequent in the IC group after CoronaVac. Following the first additional dose of mRNA BNT162, pain, induration, and tenderness at injection site, fatigue and myalgia were more frequent in the H group. A heart transplant recipient had a graft rejection temporally associated with the second CoronaVac dose, but there was no literature evidence of causal association. Four cases of AESI were considered related to the vaccine: three erythema multiforme after CoronaVac, all in IC participants, and one paresthesia after mRNA, in a H participant. Our findings were comparable to other studies that evaluated the safety of COVID-19 vaccines in different immunocompromised populations. Both vaccines were safe for immunocompromised participants.

Vaccine challenges in CLL: a comprehensive exploration of efficacy of SARS-CoV-2 immunization for patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by disease- and treatment-related immunosuppression. Patients with CLL comprise a vulnerable population to coronavirus disease 2019 (COVID-19), while the protective effect of COVID-19 vaccination remains uncertain.We conducted a systematic review to evaluate published data reporting response to COVID-19 vaccination in patients with CLL. The primary outcome was the rate of seropositivity after full primary vaccination, while secondary outcomes were rates of positive neutralizing antibodies, cellular responses, and adverse events. Response after booster doses of vaccination was also evaluated.Twenty-three studies of full primary vaccination (12 CLL-specific with 1747 patients, 11 with mixed hematologic diseases including 1044 patients with CLL) with a total of 2791 patients, and eight studies on booster doses with 389 patients were included in the analysis. The serologic response varied between studies with a median of 55%. Where reported, the median neutralizing antibody response rate was 61.2% and the cellular response rate was 44.2%. Poor serologic response was noted in patients under active treatment with anti-CD20 monoclonal antibodies, BCL2, and BTK inhibitors.The present review highlights the substantially impaired humoral and cellular response to COVID-19 vaccination in patients with CLL with patients under active treatment being the most vulnerable.

"REAl LIfe" observational study on the effectiveness of Evusheld prophylaxis against SARS-CoV-2 omicron variants in vaccine non-responder immunocompromised patients (REALISE)

BACKGROUND

Infection by SARS-CoV2 has become a challenge, especially for immunocompromised patients who show a weaker humoral response to COVID-19 vaccine. Tixagevimab+cilgavimab (Evusheld) is a combination of human monoclonal antibodies that can be used for pre-exposure prophylaxis to prevent infection or disease by SARS-CoV2.

OBJECTIVES

Our study aimed to investigate the effectiveness of Evusheld by comparing an Exposed and an Unexposed group.

STUDY DESIGN

Immunocompromised patients were enrolled in the Evusheld Group between March and September 2022. All patients had anti-spike IgG antibody levels <260 BAU/ml before administration of Evusheld. Blood samples for serological evaluations were collected, and anti-Spike antibodies were tested. For the Unexposed Group, a serologic test was performed at enrollment and a questionnaire was performed after 6 months.

RESULTS

43 patients received Evusheld pre-exposure prophylaxis and 45 patients not receiving Evusheld were enrolled in the Unexposed group. The median age was 59.0 years in the Evusheld group, and 63.0 in the unexposed group. In the Evusheld group, during the Omicron wave in Italy, 23.3% of subjects developed symptomatic infection compared to 42.2% in the unexposed group. A majority of infections was seen in male respect to female patients. No difference in length of infection between the groups was seen. Antibody level remained higher than the basal threshold at 180 days from enrollment.

CONCLUSIONS

Evusheld seems to reduce the rate of symptomatic infection in immunocompromised patients. Further data are required to determine whether this prophylaxis may have a longer-lasting effect over time.

Management of infections for patient treated with ibrutinib in clinical practice

Ibrutinib, a highly effective inhibitor of the Bruton tyrosine kinase, has significantly transformed the therapeutic approach in chronic lymphocytic leukemia (CLL). Despite these advancements, the disease continues to be characterized by immune dysfunction and increased susceptibility to infections, with mortality rates from infections showing no significant improvement over the past few decades. Therefore, timely prevention, recognition, and treatment of infections remains an important aspect of the standard management of a patient with CLL. A panel of hematologists with expertise in CLL met to discuss existing literature and clinical insights for the management of infectious in CLL undergoing ibrutinib treatment. Despite not being a fully comprehensive review on the topic, this work provides a set of practical recommendations that can serve as a guide to healthcare professionals who manage these patients in their daily clinical practice.

Vaccination of Adults With Cancer: ASCO Guideline

PURPOSE

To guide the vaccination of adults with solid tumors or hematologic malignancies.

METHODS

A systematic literature review identified systematic reviews, randomized controlled trials (RCTs), and nonrandomized studies on the efficacy and safety of vaccines used by adults with cancer or their household contacts. This review builds on a 2013 guideline by the Infectious Disease Society of America. PubMed and the Cochrane Library were searched from January 1, 2013, to February 16, 2023. ASCO convened an Expert Panel to review the evidence and formulate recommendations.

RESULTS

A total of 102 publications were included in the systematic review: 24 systematic reviews, 14 RCTs, and 64 nonrandomized studies. The largest body of evidence addressed COVID-19 vaccines.

RECOMMENDATIONS

The goal of vaccination is to limit the severity of infection and prevent infection where feasible. Optimizing vaccination status should be considered a key element in the care of patients with cancer. This approach includes the documentation of vaccination status at the time of the first patient visit; timely provision of recommended vaccines; and appropriate revaccination after hematopoietic stem-cell transplantation, chimeric antigen receptor T-cell therapy, or B-cell-depleting therapy. Active interaction and coordination among healthcare providers, including primary care practitioners, pharmacists, and nursing team members, are needed. Vaccination of household contacts will enhance protection for patients with cancer. Some vaccination and revaccination plans for patients with cancer may be affected by the underlying immune status and the anticancer therapy received. As a result, vaccine strategies may differ from the vaccine recommendations for the general healthy adult population vaccine.Additional information is available at www.asco.org/supportive-care-guidelines.

Vaccinations in patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by immune dysfunction resulting in heightened susceptibility to infections and elevated rates of morbidity and mortality. A key strategy to mitigate infection-related complications has been immunization against common pathogens. However, the immunocompromised status of CLL patients poses challenges in eliciting an adequate humoral and cellular immune response to vaccination. Most CLL-directed therapy disproportionately impairs humoral immunity. Vaccine responsiveness also depends on the phase and type of immune response triggered by immunization. In this review, we discuss the immune dysfunction, vaccine responsiveness, and considerations for optimizing vaccine response in patients with CLL.

Efficacy of Preexposure Prophylaxis with Monoclonal Antibody Tixagevimab-Cilgavimab against Emerging SARS-CoV-2 Resistant Variants in Patients with Chronic Lymphocytic Leukemia

INTRODUCTION

Preexposure prophylaxis with monoclonal antibodies (mAbs) was developed in addition to COVID-19 vaccine for immunocompromised and those with insufficient immune response, among them patients with CLL. Omicron variant and its sublineages evolved mutations that escape mAbs neutralizing effect, yet the extent of which was not studied.

METHODS

We evaluated anti-spike titers and neutralization activity of COVID-19 wild-type (WT), Delta, Omicron, BA.2, BA.4, and BA.5 before and after tixagevimab-cilgavimab (TGM/CGM) dose of 150/150 mg or 300/300 mg in patients with CLL.

RESULTS

70 patients were tested 2 weeks before and 4 weeks after receiving TGM/CGM mAbs. After TGM/CGM, anti-spike ab level increased 170-folds from 13.6 binding antibody unit (BAU)/mL (IQR, 0.4-288) to 2,328 BAU/mL (IQR, 1,681-3,500). Neutralization activity increased in all variants and was 176-folds higher in WT and 55-folds higher in Delta compared to 10-folds higher in Omicron and its sublineages (BA.2 ×11, BA.4 ×4, BA.5 ×18). Over follow-up period of 3 months, 20 patients (29%) with CLL acquired COVID-19 infection, all recovered uneventfully. In a multivariate analysis, anti-spike antibody titer was found a significant predictor for post-TGM/CGM COVID-19 infection.

CONCLUSION

Efficacy of preexposure prophylaxis with TGM/CGM in patients with CLL is significantly reduced in era of Omicron and its sublineages BA.2, BA.4, and BA.5.

Redox-Responsive Polymeric Nanoparticle for Nucleic Acid Delivery and Cancer Therapy: Progress, Opportunities, and Challenges

Cancer development and progression of cancer are closely associated with the activation of oncogenes and loss of tumor suppressor genes. Nucleic acid drugs (e.g., siRNA, mRNA, and DNA) are widely used for cancer therapy due to their specific ability to regulate the expression of any cancer-associated genes. However, nucleic acid drugs are negatively charged biomacromolecules that are susceptible to serum nucleases and cannot cross cell membrane. Therefore, specific delivery tools are required to facilitate the intracellular delivery of nucleic acid drugs. In the past few decades, a variety of nanoparticles (NPs) are designed and developed for nucleic acid delivery and cancer therapy. In particular, the polymeric NPs in response to the abnormal redox status in cancer cells have garnered much more attention as their potential in redox-triggered nanostructure dissociation and rapid intracellular release of nucleic acid drugs. In this review, the important genes or signaling pathways regulating the abnormal redox status in cancer cells are briefly introduced and the recent development of redox-responsive NPs for nucleic acid delivery and cancer therapy is systemically summarized. The future development of NPs-mediated nucleic acid delivery and their challenges in clinical translation are also discussed.

Initial Efficacy of the COVID-19 mRNA Vaccine Booster and Subsequent Breakthrough Omicron Variant Infection in Patients with B-Cell Non-Hodgkin's Lymphoma: A Single-Center Cohort Study

It has been suggested that the effect of coronavirus disease 2019 (COVID-19) booster vaccination in patients with B-cell non-Hodgkin's lymphoma (B-NHL) is inferior to that in healthy individuals. However, differences according to histological subtype or treatment status are unclear. In addition, there has been less research on patients who subsequently develop breakthrough infections. We investigated the effects of the first COVID-19 booster vaccination for patients with B-NHL and the clinical features of breakthrough infections in the Omicron variant era. In this study, B-NHL was classified into two histological subtypes: aggressive lymphoma and indolent lymphoma. Next, patients were subdivided according to treatment with anticancer drugs at the start of the first vaccination. We also examined the clinical characteristics and outcomes of patients who had breakthrough infections after a booster vaccination. The booster effect of the COVID-19 mRNA vaccine in patients with B-NHL varied considerably depending on treatment status at the initial vaccination. In the patient group at more than 1 year after the last anticancer drug treatment, regardless of the histological subtype, the booster effect was comparable to that in the healthy control group. In contrast, the booster effect was significantly poorer in the other patient groups. However, of the 213 patients who received the booster vaccine, 22 patients (10.3%) were infected with COVID-19, and 18 patients (81.8%) had mild disease; these cases included the patients who remained seronegative. Thus, we believe that booster vaccinations may help in reducing the severity of Omicron variant COVID-19 infection in patients with B-NHL.

Immunogenicity and clinical effectiveness of mRNA vaccine booster against SARS-CoV-2 Omicron in patients with haematological malignancies: A national prospective cohort study

Information regarding the protective anti-SARS-CoV-2 antibody levels and the effectiveness of the mRNA vaccines against the Omicron variant in patients with haematological malignancies is limited. We prospectively followed two times BNT162b2 vaccinated oncohaematological patients (n = 1010) without prior COVID-19 for PCR-confirmed breakthrough infections during the Alpha/Delta and the Omicron phases of the pandemic. Anti-S1-IgG levels were longitudinally monitored in patients who had received the third (booster) vaccine dose. Patients with anti-S1-IgG levels <50 BAU/mL 1 month after the booster had a higher risk of Omicron infections (RR 1.91; 95% CI 1.39-2.63; p = 0.0001) and severe infections (RR 8.74; 95% CI 3.99-19.1; p < 0.0001). Conversely, the risk of severe COVID-19 was <1% with anti-S1-IgG levels >500 BAU/mL and neutralizing antibody concentrations >50 U/mL. The risks of breakthrough Omicron infections (HR 0.55; 95% CI 0.32-0.96; p = 0.034) and severe COVID-19 (HR 0.27; 95% 0.11-0.7; p = 0.0074) were lower among patients who had received the booster dose. In conclusion, low antibody levels are associated with significantly increased risk of both the breakthrough Omicron infections and severe COVID-19. The third mRNA vaccine dose improved the protection against the Omicron and reduced the risk of severe disease.

Australia and New Zealand consensus position statement: use of COVID-19 therapeutics in patients with haematological malignancies

Despite widespread vaccination rates, we are living with high transmission rates of SARS-CoV-2. Although overall hospitalisation rates are falling, the risk of serious infection remains high for patients who are immunocompromised because of haematological malignancies. In light of the ongoing pandemic and the development of multiple agents for treatment, representatives from the Haematology Society of Australia and New Zealand and infectious diseases specialists have collaborated on this consensus position statement regarding COVID-19 management in patients with haematological disorders. It is our recommendation that both patients with haematological malignancies and treating specialists be educated regarding the preventive and treatment options available and that patients continue to receive adequate vaccinations, keeping in mind the suboptimal vaccine responses that occur in haematology patients, in particular, those with B-cell malignancies and on B-cell-targeting or depleting therapy. Patients with haematological malignancies should receive treatment for COVID-19 in accordance with the severity of their symptoms, but even mild infections should prompt early treatment with antiviral agents. The issue of de-isolation following COVID-19 infection and optimal time to treatment for haematological malignancies is discussed but remains an area with evolving data. This position statement is to be used in conjunction with advice from infectious disease, respiratory and intensive care specialists, and current guidelines from the National COVID-19 Clinical Evidence Taskforce and the New Zealand Ministry of Health and Cancer Agency Te Aho o Te Kahu COVID-19 Guidelines.

Dynamics of humoral and cellular response to three doses of anti-SARS-CoV-2 BNT162b2 vaccine in patients with hematological malignancies and older subjects

Background

Few data are available about the durability of the response, the induction of neutralizing antibodies, and the cellular response upon the third dose of the anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in hemato-oncological patients.

Objective

To investigate the antibody and cellular response to the BNT162b2 vaccine in patients with hematological malignancy.

Methods

We measured SARS-CoV-2 anti-spike antibodies, anti-Omicron neutralizing antibodies, and T-cell responses 1 month after the third dose of vaccine in 93 fragile patients with hematological malignancy (FHM), 51 fragile not oncological subjects (FNO) aged 80-92, and 47 employees of the hospital (healthcare workers, (HW), aged 23-66 years. Blood samples were collected at day 0 (T0), 21 (T1), 35 (T2), 84 (T3), 168 (T4), 351 (T pre-3D), and 381 (T post-3D) after the first dose of vaccine. Serum IgG antibodies against S1/S2 antigens of SARS-CoV-2 spike protein were measured at every time point. Neutralizing antibodies were measured at T2, T3 (anti-Alpha), T4 (anti-Delta), and T post-3D (anti-Omicron). T cell response was assessed at T post-3D.

Results

An increase in anti-S1/S2 antigen antibodies compared to T0 was observed in the three groups at T post-3D. After the third vaccine dose, the median antibody level of FHM subjects was higher than after the second dose and above the putative protection threshold, although lower than in the other groups. The neutralizing activity of antibodies against the Omicron variant of the virus was tested at T2 and T post-3D. 42.3% of FHM, 80,0% of FNO, and 90,0% of HW had anti-Omicron neutralizing antibodies at T post-3D. To get more insight into the breadth of antibody responses, we analyzed neutralizing capacity against BA.4/BA.5, BF.7, BQ.1, XBB.1.5 since also for the Omicron variants, different mutations have been reported especially for the spike protein. The memory T-cell response was lower in FHM than in FNO and HW cohorts. Data on breakthrough infections and deaths suggested that the positivity threshold of the test is protective after the third dose of the vaccine in all cohorts.

Conclusion

FHM have a relevant response to the BNT162b2 vaccine, with increasing antibody levels after the third dose coupled with, although low, a T-cell response. FHM need repeated vaccine doses to attain a protective immunological response.

Microfluidic antibody profiling after repeated SARS-CoV-2 vaccination links antibody affinity and concentration to impaired immunity and variant escape in patients on anti-CD20 therapy

Background

Patients with autoimmune/inflammatory conditions on anti-CD20 therapies, such as rituximab, have suboptimal humoral responses to vaccination and are vulnerable to poorer clinical outcomes following SARS-CoV-2 infection. We aimed to examine how the fundamental parameters of antibody responses, namely, affinity and concentration, shape the quality of humoral immunity after vaccination in these patients.

Methods

We performed in-depth antibody characterisation in sera collected 4 to 6 weeks after each of three vaccine doses to wild-type (WT) SARS-CoV-2 in rituximab-treated primary vasculitis patients (n = 14) using Luminex and pseudovirus neutralisation assays, whereas we used a novel microfluidic-based immunoassay to quantify polyclonal antibody affinity and concentration against both WT and Omicron (B.1.1.529) variants. We performed comparative antibody profiling at equivalent timepoints in healthy individuals after three antigenic exposures to WT SARS-CoV-2 (one infection and two vaccinations; n = 15) and in convalescent patients after WT SARS-CoV-2 infection (n = 30).

Results

Rituximab-treated patients had lower antibody levels and neutralisation titres against both WT and Omicron SARS-CoV-2 variants compared to healthy individuals. Neutralisation capacity was weaker against Omicron versus WT both in rituximab-treated patients and in healthy individuals. In the rituximab cohort, this was driven by lower antibody affinity against Omicron versus WT [median (range) KD: 21.6 (9.7-38.8) nM vs. 4.6 (2.3-44.8) nM, p = 0.0004]. By contrast, healthy individuals with hybrid immunity produced a broader antibody response, a subset of which recognised Omicron with higher affinity than antibodies in rituximab-treated patients [median (range) KD: 1.05 (0.45-1.84) nM vs. 20.25 (13.2-38.8) nM, p = 0.0002], underpinning the stronger serum neutralisation capacity against Omicron in the former group. Rituximab-treated patients had similar anti-WT antibody levels and neutralisation titres to unvaccinated convalescent individuals, despite two more exposures to SARS-CoV-2 antigen. Temporal profiling of the antibody response showed evidence of affinity maturation in healthy convalescent patients after a single SARS-CoV-2 infection, which was not observed in rituximab-treated patients, despite repeated vaccination.

Discussion

Our results enrich previous observations of impaired humoral immune responses to SARS-CoV-2 in rituximab-treated patients and highlight the significance of quantitative assessment of serum antibody affinity and concentration in monitoring anti-viral immunity, viral escape, and the evolution of the humoral response.

mRNA vaccines and their delivery strategies: A journey from infectious diseases to cancer

mRNA vaccines have evolved as promising cancer therapies. These vaccines can encode tumor-allied antigens, thus enabling personalized treatment approaches. They can also target cancer-specific mutations and overcome immune evasion mechanisms. They manipulate the body's cellular functions to produce antigens, elicit immune responses, and suppress tumors by overcoming limitations associated with specific histocompatibility leukocyte antigen molecules. However, successfully delivering mRNA into target cells destroys a crucial challenge. Viral and nonviral vectors (lipid nanoparticles and cationic liposomes) have shown great capacity in protecting mRNA from deterioration and assisting in cellular uptake. Cell-penetrating peptides, hydrogels, polymer-based nanoparticles, and dendrimers have been investigated to increase the delivery efficacy and immunogenicity of mRNA. This comprehensive review explores the landscape of mRNA vaccines and their delivery platforms for cancer, addressing design considerations, diverse delivery strategies, and recent advancements. Overall, this review contributes to the progress of mRNA vaccines as an innovative strategy for effective cancer treatment.

Detection of SARS-CoV-2-Specific Cells Utilizing Whole Proteins and/or Peptides in Human PBMCs Using IFN-ƴ ELISPOT Assay

SARS-CoV-2 continues to threaten global public health, making COVID-19 immunity studies of utmost importance. Waning of antibody responses postinfection and/or vaccination and the emergence of immune escape variants have been ongoing challenges in mitigating SARS-CoV-2 morbidity and mortality. While a tremendous amount of work has been done to characterize humoral immune responses to SARS-CoV-2 virus and vaccines, cellular immunity, mediated by T cells, is critical for efficient viral control and protection and demonstrates high durability and cross-reactivity to coronavirus variants. Thus, ELISPOT, a standard assay for antigen-specific cellular immune response assessment, allows us to evaluate SARS-CoV-2-specific T-cell response by quantifying the frequency of SARS-CoV-2-specific cytokine-secreting cells in vitro. We have outlined a detailed procedure to study T-cell recall responses to SARS-CoV-2 in human peripheral blood mononuclear cells (PBMCs) following infection and/or vaccination using an optimized IFN-γ ELISPOT assay. Our methodologies can be adapted to assess other cytokines and are a useful tool for studying other viral pathogen and/or peptide-specific T-cell responses.

The evolving landscape of COVID-19 and post-COVID condition in patients with chronic lymphocytic leukemia: A study by ERIC, the European research initiative on CLL

In this retrospective international multicenter study, we describe the clinical characteristics and outcomes of patients with chronic lymphocytic leukemia (CLL) and related disorders (small lymphocytic lymphoma and high-count monoclonal B lymphocytosis) infected by SARS-CoV-2, including the development of post-COVID condition. Data from 1540 patients with CLL infected by SARS-CoV-2 from January 2020 to May 2022 were included in the analysis and assigned to four phases based on cases disposition and SARS-CoV-2 variants emergence. Post-COVID condition was defined according to the WHO criteria. Patients infected during the most recent phases of the pandemic, though carrying a higher comorbidity burden, were less often hospitalized, rarely needed intensive care unit admission, or died compared to patients infected during the initial phases. The 4-month overall survival (OS) improved through the phases, from 68% to 83%, p = .0015. Age, comorbidity, CLL-directed treatment, but not vaccination status, emerged as risk factors for mortality. Among survivors, 6.65% patients had a reinfection, usually milder than the initial one, and 16.5% developed post-COVID condition. The latter was characterized by fatigue, dyspnea, lasting cough, and impaired concentration. Infection severity was the only risk factor for developing post-COVID. The median time to resolution of the post-COVID condition was 4.7 months. OS in patients with CLL improved during the different phases of the pandemic, likely due to the improvement of prophylactic and therapeutic measures against SARS-CoV-2 as well as the emergence of milder variants. However, mortality remained relevant and a significant number of patients developed post-COVID conditions, warranting further investigations.

Interruption of BTK inhibitor improves response to SARS-CoV-2 booster vaccination in patients with CLL

B-cell targeted therapies, including anti-CD20 monoclonal antibodies (mAb) and Bruton's tyrosine kinase inhibitors (BTKi), further suppress antibody (Ab) response to vaccines in patients with chronic lymphocytic leukemia (CLL). We conducted a prospective cohort study of SARS-CoV-2 vaccination in 81 CLL patients receiving BTKi (n = 54), venetoclax (VEN, n = 9), or who were treatment naïve (TN, n = 18). Anti-spike Ab were detected in 53% of patients on BTKi post-primary series and 84% post-booster, 57% of patients on VEN post-primary series and 50% post-booster, and 67% of TN patients post-primary series and 87% post-booster. T-cell response to the primary series was independent of Ab response. At the time of booster, 12 patients interrupted BTKi (median 21 d, range 8-22) and 33 continued BTKi. Among patients with detectable Ab post-booster, those who interrupted BTKi (n = 10) had significantly higher Ab titers (median 7149 units/mL) compared with patients who continued BTKi (n = 27, median 2071 units/mL, p = .04).

COVID-19 in Patients with Chronic Lymphocytic Leukemia: What Have We Learned?

BACKGROUND

Chronic lymphocytic leukemia (CLL) is a prevalent hematological malignancy (HM) characterized by inherent immunodeficiency, which is further pronounced by disease-directed therapy. The COVID-19 pandemic has had devastating outcomes, and although its impact has diminished over time, it continues to be a cause of significant morbidity and mortality, particularly among immunodeficient patients.

SUMMARY

In this review, we describe mechanisms of immune dysfunction in CLL in relation to COVID-19, provide an overview of the clinical outcomes of the disease in this patient population, and identify risk factors associated with severe morbidity and mortality. Additionally, we acknowledge the influence of the rapidly evolving landscape of new disease variants. The review further delineates the humoral and cellular responses to vaccination and their clinical efficacy in preventing COVID-19 in CLL patients. Moreover, we explore potential approaches to enhance these immune responses. Pre- and post-exposure prophylaxis strategies are discussed, along with description of common agents in the treatment of the disease in both outpatient and inpatient setting. Throughout the review, we emphasize the interplay between novel therapies for CLL and COVID-19 outcomes, prevention, and treatment and describe the impact of COVID-19 on the utilization of these novel agents. This information has the potential to guide clinical decision making in the management CLL patients.

KEY MESSAGES

CLL patients are at risk for severe COVID-19 infection. Vaccinations and COVID-19 directed therapy have improved outcomes in patients with CLL, yet clinical challenges persist.

Humoral and cellular responses to SARS-CoV-2 in patients with B-cell haematological malignancies improve with successive vaccination

Patients with haematological malignancies are more likely to have poor responses to vaccination. Here we provide detailed analysis of the humoral and cellular responses to COVID-19 vaccination in 69 patients with B-cell malignancies. Measurement of anti-spike IgG in serum demonstrated a low seroconversion rate with 27.1% and 46.8% of patients seroconverting after the first and second doses of vaccine, respectively. In vitro pseudoneutralisation assays demonstrated a poor neutralising response, with 12.5% and 29.5% of patients producing a measurable neutralising titre after the first and second doses, respectively. A third dose increased seropositivity to 54.3% and neutralisation to 51.5%, while a fourth dose further increased both seropositivity and neutralisation to 87.9%. Neutralisation titres post-fourth dose showed a positive correlation with the size of the B-cell population measured by flow cytometry, suggesting an improved response correlating with recovery of the B-cell compartment after B-cell depletion treatments. In contrast, interferon gamma ELISpot analysis showed a largely intact T-cell response, with the percentage of patients producing a measurable response boosted by the second dose to 75.5%. This response was maintained thereafter, with only a small increase following the third and fourth doses, irrespective of the serological response at these timepoints.

Serological Responses and Predictive Factors of Booster COVID-19 Vaccines in Patients with Hematologic Malignancies

Patients with hematologic malignancies are reported to have a more severe course of coronavirus disease 2019 (COVID-19) and be less responsive to vaccination. In this prospective study, we aimed to evaluate the serological responses to booster COVID-19 vaccines of Taiwanese patients with hematologic malignancies and identify potential predictive markers for effective neutralizing immunity. This study enrolled 68 patients with hematologic malignancies and 68 age- and gender-matched healthy control subjects who received three doses of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from 1 January 2022 to 31 October 2022. The SARS-CoV-2 immunoglobulin G (IgG) spike antibody level was measured with the Abbott assay. The effective neutralization capacity was defined as an anti-spike IgG level of ≥4160 AU/mL. Among the 68 patients with hematologic malignancies, 89.7% achieved seroconversion after booster doses. Seven patients with actively treated lymphoma remained seronegative and had the lowest humoral responses among patients with different types of hematologic malignancies. Despite comparable antibody titers between patients and healthy individuals, rates of effective neutralization (66.2% vs. 86.8%, respectively; p = 0.005) were significantly reduced in patients with hematologic malignancies. In a multivariate analysis, the independent predictors for effective neutralization were a lack of B-cell-targeted agents within six months of vaccination (odds ratio, 15.2; 95% confidence interval, 2.7-84.2; p = 0.002) and higher immunoglobulin levels (odds ratio, 4.4; 95% confidence interval, 1.3-14.7; p = 0.017). In conclusion, the majority of patients with hematologic malignancies achieved seroconversion after booster vaccination. Patients with ongoing B-cell depletion and hypogammaglobinemia were identified as having negative predictive markers for effective neutralization.

Prior cycles of anti-CD20 antibodies affect antibody responses after repeated SARS-CoV-2 mRNA vaccination

BACKGROUNDWhile B cell depletion is associated with attenuated antibody responses to SARS-CoV-2 mRNA vaccination, responses vary among individuals. Thus, elucidating the factors that affect immune responses after repeated vaccination is an important clinical need.METHODSWe evaluated the quality and magnitude of the T cell, B cell, antibody, and cytokine responses to a third dose of BNT162b2 or mRNA-1273 mRNA vaccine in patients with B cell depletion.RESULTSIn contrast with control individuals (n = 10), most patients on anti-CD20 therapy (n = 48) did not demonstrate an increase in spike-specific B cells or antibodies after a third dose of vaccine. A third vaccine elicited significantly increased frequencies of spike-specific non-naive T cells. A small subset of B cell-depleted individuals effectively produced spike-specific antibodies, and logistic regression models identified time since last anti-CD20 treatment and lower cumulative exposure to anti-CD20 mAbs as predictors of those having a serologic response. B cell-depleted patients who mounted an antibody response to 3 vaccine doses had persistent humoral immunity 6 months later.CONCLUSIONThese results demonstrate that serial vaccination strategies can be effective for a subset of B cell-depleted patients.FUNDINGThe NIH (R25 NS079193, P01 AI073748, U24 AI11867, R01 AI22220, UM 1HG009390, P01 AI039671, P50 CA121974, R01 CA227473, U01CA260507, 75N93019C00065, K24 AG042489), NIH HIPC Consortium (U19 AI089992), the National Multiple Sclerosis Society (CA 1061-A-18, RG-1802-30153), the Nancy Taylor Foundation for Chronic Diseases, Erase MS, and the Claude D. Pepper Older Americans Independence Center at Yale (P30 AG21342).

Booster effect of a third mRNA-based COVID-19 vaccine dose in patients with myeloid malignancies

BACKGROUND

We have reported that seroconversion rates after the second dose of mRNA-based COVID-19 vaccines for myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) were 100% and 95% respectively, with no significant difference from healthy controls (HCs).However, there are very limited data for the response to a third vaccine dose in those patients.

AIMS

In this complementary study, we investigated the booster effect of a third mRNA-based COVID-19 vaccine dose in patients with myeloid malignancies.

MATERIALS & METHODS

A total 58 patients including 20 patients with MDS and 38 patients with AML were enrolled. Anti-SARS-CoV-2S immunoassays were performed at 3, 6, and 9 months after the second vaccine dose.

RESULTS

Seventy-five percent of the MDS patients and 37% of the AML patients were receiving active treatment at the time of the third vaccination. Both the initial and third vaccine response in AML patients were comparable to those in HCs. In MDS patients, although the initial vaccine immunogenicity was inferior to that in HCs and AML patients, the third vaccine improved the response to a level not inferior to those in HCs and AML patients. Of note, the third vaccine resulted in a significant increase of antibodies in actively treated MDS patients who had shown a response inferior to that in untreated patients after two doses of vaccination.

DISCUSSION

In patients with myeloid malignancies, the third vaccine dose showed a booster effect, and disease- and therapy-related factors associated with the booster response have been identified.

CONCLUSION

The third dose of an mRNA-based COVID-19 vaccine showed a booster effect in patients with myeloid malignancies. Such a good booster response has not been reported in other haematological malignancies.

First-Line Treatment of Older Patients with CLL: A New Approach in the Chemo-Free Era

Bruton tyrosine kinase inhibitors (BTKi) and the BCL2 inhibitor venetoclax, with or without the anti-CD20 monoclonal antibody Obinutuzumab, represent the preferred options for the first-line therapy of CLL because they are more effective and may improve quality of life. However, patient inclusion criteria are heterogeneous across trials designed for older patients, and the identification of CLL-specific parameters identifying unfit patients at risk of developing drug-specific adverse events is required to guide treatment choice. Due to inclusion/exclusion criteria in trials, higher discontinuation rates with BTKi were reported in real-world studies, and registry analyses provided useful information on factors predicting earlier discontinuation in a real-world setting. Though targeted agents were shown to be cost-effective treatments in high-income countries, the out-of-pocket expenses may limit accessibility to these drugs, and the overall expenditure for new drugs in CLL is projected to increase substantially, posing an issue for sustainability. This being said, the choice of a finite-duration treatment based on venetoclax-containing regimens or treatment until progression with BTKi is today possible in high-income countries, and the therapy choice drivers are represented by coexisting medical conditions rather than age, patient expectations, logistics, and sustainability.

Exposure of progressive immune dysfunction by SARS-CoV-2 mRNA vaccination in patients with chronic lymphocytic leukemia: A prospective cohort study

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL) have reduced seroconversion rates and lower binding antibody (Ab) and neutralizing antibody (NAb) titers than healthy individuals following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA vaccination. Here, we dissected vaccine-mediated humoral and cellular responses to understand the mechanisms underlying CLL-induced immune dysfunction.

METHODS AND FINDINGS

We performed a prospective observational study in SARS-CoV-2 infection-naïve CLL patients (n = 95) and healthy controls (n = 30) who were vaccinated between December 2020 and June 2021. Sixty-one CLL patients and 27 healthy controls received 2 doses of the Pfizer-BioNTech BNT162b2 vaccine, while 34 CLL patients and 3 healthy controls received 2 doses of the Moderna mRNA-1273 vaccine. The median time to analysis was 38 days (IQR, 27 to 83) for CLL patients and 36 days (IQR, 28 to 57) for healthy controls. Testing plasma samples for SARS-CoV-2 anti-spike and receptor-binding domain Abs by enzyme-linked immunosorbent assay (ELISA), we found that all healthy controls seroconverted to both antigens, while CLL patients had lower response rates (68% and 54%) as well as lower median titers (23-fold and 30-fold; both p < 0.001). Similarly, NAb responses against the then prevalent D614G and Delta SARS-CoV-2 variants were detected in 97% and 93% of controls, respectively, but in only 42% and 38% of CLL patients, who also exhibited >23-fold and >17-fold lower median NAb titers (both p < 0.001). Interestingly, 26% of CLL patients failed to develop NAbs but had high-titer binding Abs that preferentially reacted with the S2 subunit of the SARS-CoV-2 spike. Since these patients were also seropositive for endemic human coronaviruses (HCoVs), these responses likely reflect cross-reactive HCoV Abs rather than vaccine-induced de novo responses. CLL disease status, advanced Rai stage (III-IV), elevated serum beta-2 microglobulin levels (β2m >2.4 mg/L), prior therapy, anti-CD20 immunotherapy (<12 months), and intravenous immunoglobulin (IVIg) prophylaxis were all predictive of an inability to mount SARS-CoV-2 NAbs (all p ≤ 0.03). T cell response rates determined for a subset of participants were 2.8-fold lower for CLL patients compared to healthy controls (0.05, 95% CI 0.01 to 0.27, p < 0.001), with reduced intracellular IFNγ staining (p = 0.03) and effector polyfunctionality (p < 0.001) observed in CD4+ but not in CD8+ T cells. Surprisingly, in treatment-naïve CLL patients, BNT162b2 vaccination was identified as an independent negative risk factor for NAb generation (5.8, 95% CI 1.6 to 27, p = 0.006). CLL patients who received mRNA-1273 had 12-fold higher (p < 0.001) NAb titers and 1.7-fold higher (6.5, 95% CI 1.3 to 32, p = 0.02) response rates than BNT162b2 vaccinees despite similar disease characteristics. The absence of detectable NAbs in CLL patients was associated with reduced naïve CD4+ T cells (p = 0.03) and increased CD8+ effector memory T cells (p = 0.006). Limitations of the study were that not all participants were subjected to the same immune analyses and that pre-vaccination samples were not available.

CONCLUSIONS

CLL pathogenesis is characterized by a progressive loss of adaptive immune functions, including in most treatment-naïve patients, with preexisting memory being preserved longer than the capacity to mount responses to new antigens. In addition, higher NAb titers and response rates identify mRNA-1273 as a superior vaccine for CLL patients.

Risk of Infections Secondary to the Use of Targeted Therapies in Hematological Malignancies

Concurrent infections in hematological malignancies (HM) are major contributors to adverse clinical outcomes, including prolonged hospitalization and reduced life expectancy. Individuals diagnosed with HM are particularly susceptible to infectious pathogens due to immunosuppression, which can either be inherent to the hematological disorder or induced by specific therapeutic strategies. Over the years, the treatment paradigm for HM has witnessed a tremendous shift, from broad-spectrum treatment approaches to more specific targeted therapies. At present, the therapeutic landscape of HM is constantly evolving due to the advent of novel targeted therapies and the enhanced utilization of these agents for treatment purposes. By initiating unique molecular pathways, these agents hinder the proliferation of malignant cells, consequently affecting innate and adaptive immunity, which increases the risk of infectious complications. Due to the complexity of novel targeted therapies and their associated risks of infection, it often becomes a daunting task for physicians to maintain updated knowledge in their clinical practice. The situation is further aggravated by the fact that most of the initial clinical trials on targeted therapies provide inadequate information to determine the associated risk of infection. In such a scenario, a cumulative body of evidence is paramount in guiding clinicians regarding the infectious complications that can arise following targeted therapies. In this review, I summarize the recent knowledge on infectious complications arising in the context of targeted therapies for HM.

Improved plasmablast response after repeated pneumococcal revaccinations following primary immunization with 13-valent pneumococcal conjugate vaccine or 23-valent pneumococcal polysaccharide vaccine in patients with chronic lymphocytic leukemia

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL) show an immune dysfunction with increased risk of infections and poor response to vaccination. Streptococcus pneumoniae is a common cause of morbidity and mortality in CLL patients. In a previous randomized clinical trial, we found a superior immune response in CLL patients receiving conjugated pneumococcal vaccine compared to non-conjugated vaccine. The response to revaccination in CLL patients is scarcely studied. In this study, early humoral response to repeated revaccinations with pneumococcal vaccines was evaluated, by determination of B cell subsets and plasmablast dynamics in peripheral blood.

METHOD

CLL patients (n = 14) and immunocompetent controls (n = 31) were revaccinated with a 13-valent pneumococcal conjugate vaccine (PCV13) after previous primary immunization (3-6 years ago) with PCV13 or a 23-valent pneumococcal polysaccharide vaccine (PPSV23). Eight weeks after the first revaccination, all CLL patients received a second revaccination with PCV13 or PPSV23. B cell subsets including plasmablasts were analyzed in peripheral blood by flow cytometry, before and after the first and the second revaccination.

RESULTS

None of the CLL patients, but all controls, had detectable plasmablasts at baseline (p < 0.001). After the first revaccination with PCV13, the plasmablast proportions did not increase in CLL patients (p = 0.13), while increases were seen in controls (p < 0.001). However, after a second revaccination with PCV13 or PPSV23, plasmablasts increased compared to baseline also in CLL patients (p < 0.01). If no response was evident after first revaccination, only a second revaccination with PCV13 increased plasmablasts in contrast to PPSV23 revaccination. Patients with hypogammaglobulinemia and ongoing/previous CLL specific treatment responded poorly, also to a second revaccination.

CONCLUSION

In CLL patients, pneumococcal revaccination induced minor early plasmablast response compared to controls, but the response improved using a strategy of repeated doses with of conjugated T cell dependent pneumococcal vaccine.

Humoral response to mRNA-based COVID-19 vaccine and booster effect of a third dose in patients with mature T cell and NK-cell neoplasms

Patients with lymphoid malignancies have impaired humoral immunity caused by the disease itself and its treatment, placing them at risk for severe coronavirus disease-19 (COVID-19) and reduced response to vaccination. However, data for COVID-19 vaccine responses in patients with mature T cell and NK-cell neoplasms are very limited. In this study of 19 patients with mature T/NK-cell neoplasms, anti-severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike antibodies were measured at 3 months, 6 months, and 9 months after the second mRNA-based vaccination. At the time of the second and third vaccinations, 31.6% and 15.4% of the patients were receiving active treatment. All patients received the primary vaccine dose and the third vaccination rate was 68.4%. In patients with mature T/NK-cell neoplasms, both seroconversion rate (p < 0.01) and antibody titers (p < 0.01) after the second vaccination were significantly lower than those in healthy controls (HC). In individuals who received the booster dose, patients had significantly lower antibody titers than those in HC (p < 0.01); however, the seroconversion rate in patients was 100%, which was the same as that in HC. The booster vaccine resulted in a significant increase of antibodies in elderly patients who had shown a response that was inferior to that in younger patients after two doses of vaccination. Since higher antibody titers and higher seroconversion rate reduced the incidence of infection and mortality, vaccination more than three times may have the advantage for patients with mature T/NK-cell neoplasms, especially in elderly patients. Clinical trial registration number: UMIN 000,045,267 (August 26th, 2021), 000,048,764 (August 26th, 2022).

Selective suppression of de novo SARS-CoV-2 vaccine antibody responses in patients with cancer on B cell-targeted therapy

We assessed vaccine-induced antibody responses to the SARS-CoV-2 ancestral virus and Omicron variant before and after booster immunization in 57 patients with B cell malignancies. Over one-third of vaccinated patients at the pre-booster time point were seronegative, and these patients were predominantly on active cancer therapies such as anti-CD20 monoclonal antibody. While booster immunization was able to induce detectable antibodies in a small fraction of seronegative patients, the overall booster benefit was disproportionately evident in patients already seropositive and not receiving active therapy. While ancestral virus- and Omicron variant-reactive antibody levels among individual patients were largely concordant, neutralizing antibodies against Omicron tended to be reduced. Interestingly, in all patients, including those unable to generate detectable antibodies against SARS-CoV-2 spike, we observed comparable levels of EBV- and influenza-reactive antibodies, demonstrating that B cell-targeting therapies primarily impair de novo but not preexisting antibody levels. These findings support rationale for vaccination before cancer treatment.

A case of SARS-CoV-2 Omicron reinfection resulting in a significant immunity boost in a paediatric patient affected by B-cell acute lymphoblastic leukemia

BACKGROUND

Since its emergence in November 2021, SARS-CoV-2 Omicron clade has quickly become dominant, due to its increased transmissibility and immune evasion. Different sublineages are currently circulating, which differ in mutations and deletions in regions of the SARS-CoV-2 genome implicated in the immune response. In May 2022, BA.1 and BA.2 were the most prevalent sublineages in Europe, both characterized by ability of evading natural acquired and vaccine-induced immunity and of escaping monoclonal antibodies neutralization.

CASE PRESENTATION

A 5-years old male affected by B-cell acute lymphoblastic leukemia in reinduction was tested positive for SARS-CoV-2 by RT-PCR at the Bambino Gesù Children Hospital in Rome in December 2021. He experienced a mild COVID-19 manifestation, and a peak of nasopharyngeal viral load corresponding to 15.5 Ct. Whole genome sequencing identified the clade 21 K (Omicron), sublineage BA.1.1. The patient was monitored over time and tested negative for SARS-CoV-2 after 30 days. Anti-S antibodies were detected positive with modest titre (3.86 BAU/mL), while anti-N antibodies were negative. 74 days after the onset of the first infection and 23 days after the last negative test, the patient was readmitted to hospital with fever, and tested positive for SARS-CoV-2 by RT-PCR (peak of viral load corresponding to 23.3 Ct). Again, he experienced a mild COVID-19. Whole genome sequencing revealed an infection with the Omicron lineage BA.2 (21L clade). Sotrovimab administration was started at the fifth day of positivity, and RT-PCR negativity occurred 10 days later. Surveillance SARS-CoV-2 RT-PCR were persistently negative, and in May 2022, anti-N antibodies were found positive and anti-S antibodies reached titres > 5000 BAU/mL.

CONCLUSIONS

By this clinical case, we showed that SARS-CoV-2 reinfection within the Omicron clade can occur and can be correlated to inadequate immune responses to primary infection. We also showed that the infection's length was shorter in the second respect to first episode, suggesting that pre-existing T cell-mediated immunity, though not preventing re-infection, might have limited the SARS-CoV-2 replication capacity. Lastly, Sotrovimab treatment retained activity against BA.2, probably accelerating the viral clearance in the second infectious episode, after which seroconversion and increase of anti-S antibodies titres were observed.

Prospective comprehensive profiling of immune responses to COVID-19 vaccination in patients on zanubrutinib therapy

Zanubrutinib-treated and treatment-naïve patients with chronic lymphocytic leukaemia (CLL) or Waldenstrom's macroglobulinaemia were recruited in this prospective study to comprehensively profile humoral and cellular immune responses to COVID-19 vaccination. Overall, 45 patients (median 72 years old) were recruited; the majority were male (71%), had CLL (76%) and were on zanubrutinib (78%). Seroconversion rates were 65% and 77% following two and three doses, respectively. CD4+ and CD8+ T-cell response rates increased with third dose. In zanubrutinib-treated patients, 86% developed either a humoral or cellular response. Patients on zanubrutinib developed substantial immune responses following two COVID-19 vaccine doses, which further improved following a third dose.

Evaluation of Antibody Responses in Patients with B-Cell Malignancies after Two and Three Doses of Anti-SARS-CoV-2 S Vaccination-A Retrospective Cohort Study

Patients with B-cell malignancies are at a higher risk of severe SARS-CoV-2 infections. Nevertheless, extensive data on the immune responses of hematological patients and the efficacy of the third dose of the vaccine are scarce. The goal of this study was to determine standardized anti-SARS-CoV-2 S antibody levels and to evaluate differences between treatment modalities in response to the second and third vaccines among patients with B-cell malignancies treated at the University Hospital Krems and the University Hospital of Vienna. The antibody levels of a total of 80 patients were retrospectively analyzed. The results indicate a significant increase in antibody production in response to the third vaccination. The highest increases could be observed in patients in a "watchful-waiting" and "off-therapy" setting. Encouragingly, approximately one-third of patients who did not develop antibodies in response to two vaccinations achieved seroconversion after the third vaccination. "Watchful-waiting", "off-therapy" and treatment with BTK inhibitors were indicative for increased antibody response after the third dose compared to anti-CD19 CAR T-cell and anti-CD-20 antibody treatment. In summary, the results of this study underline the pre-eminent role of the need for complete vaccination with three doses for the development of protective immunity in patients with B-cell malignancies.

Three doses of BNT162b2 COVID-19 mRNA vaccine establish long-lasting CD8+ T cell immunity in CLL and MDS patients

Patients with hematological malignancies are prioritized for COVID-19 vaccine due to their high risk for severe SARS-CoV-2 infection-related disease and mortality. To understand T cell immunity, its long-term persistence, and its correlation with antibody response, we evaluated the BNT162b2 COVID-19 mRNA vaccine-specific immune response in chronic lymphocytic leukemia (CLL) and myeloid dysplastic syndrome (MDS) patients. Longitudinal analysis of CD8⁺ T cells using DNA-barcoded peptide-MHC multimers covering the full SARS-CoV-2 Spike-protein (415 peptides) showed vaccine-specific T cell activation and persistence of memory T cells up to six months post-vaccination. Surprisingly, a higher frequency of vaccine-induced antigen-specific CD8⁺ T cells was observed in the patient group compared to a healthy donor group. Furthermore, and importantly, immunization with the second booster dose significantly increased the frequency of antigen-specific CD8⁺ T cells as well as the total number of T cell specificities. Altogether 59 BNT162b2 mRNA vaccine-derived immunogenic responses were identified, of which 23 established long-term CD8⁺ T cell memory response with a strong immunodominance for NYNYLYRLF (HLA-A24:02) and YLQPRTFLL (HLA-A02:01) epitopes. In summary, we mapped the vaccine-induced antigen-specific CD8⁺ T cells and showed a booster-specific activation and enrichment of memory T cells that could be important for long-term disease protection in this patient group.

Potent high-avidity neutralizing antibodies and T cell responses after COVID-19 vaccination in individuals with B cell lymphoma and multiple myeloma

Individuals with hematologic malignancies are at increased risk for severe coronavirus disease 2019 (COVID-19), yet profound analyses of COVID-19 vaccine-induced immunity are scarce. Here we present an observational study with expanded methodological analysis of a longitudinal, primarily BNT162b2 mRNA-vaccinated cohort of 60 infection-naive individuals with B cell lymphomas and multiple myeloma. We show that many of these individuals, despite markedly lower anti-spike IgG titers, rapidly develop potent infection neutralization capacities against several severe acute respiratory syndrome coronavirus 2 variants of concern (VoCs). The observed increased neutralization capacity per anti-spike antibody unit was paralleled by an early step increase in antibody avidity between the second and third vaccination. All individuals with hematologic malignancies, including those depleted of B cells and individuals with multiple myeloma, exhibited a robust T cell response to peptides derived from the spike protein of VoCs Delta and Omicron (BA.1). Consistently, breakthrough infections were mainly of mild to moderate severity. We conclude that COVID-19 vaccination can induce broad antiviral immunity including ultrapotent neutralizing antibodies with high avidity in different hematologic malignancies.

Humoral Effect of SARS-CoV-2 mRNA vaccination with booster dose in solid tumor patients with different anticancer treatments

Introduction

Cancer patients are at risk for serious complications in case of SARS-CoV-2 infection. In these patients SARS-CoV-2 vaccination is strongly recommended, with the preferential use of mRNA vaccines. The antibody response in cancer patients is variable, depending on the type of cancer and antitumoral treatment. In solid tumor patients an antibody response similar to healthy subjects has been confirmed after the second dose. Only few studies explored the duration of immunization after the two doses and the effect of the third dose.

Methods

In our study we explored a cohort of 273 solid tumor patients at different stages and treated with different anticancer therapies.

Results and Discussion

Our analysis demonstrated that the persistence of the neutralizing antibody and the humoral response after the booster dose of vaccine was not dependent on either the tumor type, the stage or type of anticancer treatment.

Cellular and humoral response to the fourth BNT162b2 mRNA COVID-19 vaccine dose in patients with CLL

We assessed the humoral and cellular response to the fourth BNT162b2 mRNA COVID-19 vaccine dose in patients with CLL. A total of 67 patients with CLL and 85 age matched controls tested for serologic response and pseudo-neutralization assay. We also tested the functional T-cell response by interferon gamma (IFNγ) to spike protein in 26 patients. Two weeks after the fourth vaccine antibody serologic response was evident in 37 (55.2%) patients with CLL, 20 /22 (91%) of treatment naïve, and 9/32 (28%) patients with ongoing therapy, compared with 100% serologic response in age matched controls. The antibody titer increased by 10-fold in patients with CLL, however, still 88-folds lower than age matched controls. Predictors of better chances of post fourth vaccination serologic response were previous positive serologies after second, third, and pre-fourth vaccination, neutralizing assay, and treatment naïve patients. T-cell response improved from 42.3% before the fourth vaccine to 84.6% 2 weeks afterwards. During the time period of 3 months after the fourth vaccination, 14 patients (21%) developed COVID-19 infection, all recovered uneventfully. Our data demonstrate that fourth SARS-CoV-2 vaccination improves serologic response in patients with CLL to a lesser extent than healthy controls and induces functional T-cell response.

Immune Response to COVID-19 Vaccination in Hematologic Malignancies: A Mini-Review

The outbreak of the COVID-19 infection has led to the rapidity of vaccine usage in recent years. Emerging data indicate that the efficacy of vaccination against COVID-19 was about 95% in the general population, though its impact is impaired in patients with hematologic malignancies. As such, we decided to research the publications in which the authors reported the impacts of COVID-19 vaccination in patients suffering from hematologic malignancies. We concluded that patients with hematologic malignancies have lower responses, antibody titers as well as an impaired humoral response following vaccination, notably in patients with chronic lymphocytic leukemia (CLL) and lymphoma. Furthermore, it seems that the status of treatment can significantly affect the responses to the COVID-19 vaccination.

Vaccination efficacy in patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a disorder of mature malignant B cells with multiple elements of immune dysfunction. Infections are common in CLL patients due to complex immunodeficiency. Vaccines are used as preventative measures for common diseases including influenza, pneumococcus, tetanus/diphtheria and shingles in the general population. Vaccines are utilized to mitigate this risk, although there have been some concerns regarding the efficacy of vaccines in the CLL population due to the inherent complex immune dysfunction associated with the disease. In this review, we describe the clinical and laboratory indicators for efficacy of the vaccines in the CLL population (including COVID-19, influenza, pneumonia, herpes zoster, and tetanus) and discuss immunization recommendations for patients with CLL.

COVID-19 Vaccination Response and Its Practical Application in Patients With Chronic Lymphocytic Leukemia

Patients with chronic lymphocyticleukemia (CLL) typically have innate/adaptive immune system dysregulation, thus the protective effect of coronavirus disease 2019 (COVID-19) vaccination remains uncertain. This prospective review evaluates vaccination response in these patients, including seropositivity rates by CLL treatment status, type of treatment received, and timing of vaccination. Antibody persistence, predictors of poor vaccine response, and severity of COVID-19 infection in vaccinated patients were also analyzed. Practical advice on the clinical management of patients with CLL is provided. Articles reporting COVID-19 vaccination in patients with CLL, published January 1, 2021-May 1, 2022, were included. Patients with CLL displayed the lowest vaccination responses among hematologic malignancies; however, seropositivity increased with each vaccination. One of the most commonly reported independent risk factors for poor vaccine response was active CLL treatment; others included hypogammaglobulinemia and age >65-70 years. Patients who were treatment-naive, off therapy, in remission, or who had a prior COVID-19 infection displayed the greatest responses. Further data are needed on breakthrough infection rates and a heterologous booster approach in patients with hematologic malignancies. Although vaccine response was poor for patients on active therapy regardless of treatment type, CLL management in the context of COVID-19 should aim to avoid delays in antileukemic treatment, especially with the advent of numerous strategies to mitigate risk of severe COVID-19 such as pre-exposure prophylaxis, and highly effective antivirals and monoclonal antibody therapy upon confirmed infection. Patients with CLL should remain vigilant in retaining standard prevention measures such as masks, social distancing, and hand hygiene.

Third dose of an mRNA COVID-19 vaccine for patients with multiple myeloma

We have reported that IgG antibody responses following two mRNA COVID-19 vaccinations are impaired among patients with multiple myeloma (MM). In the current study, sixty-seven patients with MM were tested for anti-spike IgG antibodies 0-60 days prior to their first vaccination, 14-28 days following the second dose, and both before and 14-28 days after their third dose of the mRNA-1273 or BNT162b2 vaccines. After the first two doses, most patients' (93 %) antibody levels declined to ineffective levels (<250 BAU/mL) prior to their third dose (D3). D3 elicited responses in 84 % of patients (61 % full response and 22 % partial response). The third vaccination increased antibody levels (average = 370.4 BAU/mL; range, 1.0-8977.3 BAU/mL) relative to just prior to D3 (average = 25.0 BAU/mL; range, 1.0-683.8 BAU/mL) and achieved higher levels than peak levels after the first two doses (average = 144.8 BAU/mL; range, 1.0-4,284.1 BAU/mL). D3 response positively correlated with mRNA-1273, a > 10-fold change from baseline for the two-dose series, switching from BNT162b2 to mRNA-1273 for D3, and treatment with elotuzumab and an immunomodulatory agent. Lower antibody levels prior to D3, poorer overall response to first two doses, and ruxolitinib or anti-CD38 monoclonal antibody treatment negatively correlated with D3 response. Our results show encouraging activity of the third vaccine, even among patients who failed to respond to the first two vaccinations. The finding of specific factors that predict COVID-19 antibody levels will help advise patients and healthcare professionals on the likelihood of responses to further vaccinations.

Coronavirus-Specific Antibody and T Cell Responses Developed after Sputnik V Vaccination in Patients with Chronic Lymphocytic Leukemia

The clinical course of the new coronavirus disease 2019 (COVID-19) has shown that patients with chronic lymphocytic leukemia (CLL) are characterized by a high mortality rate, poor response to standard treatment, and low virus-specific antibody response after recovery and/or vaccination. To date, there are no data on the safety and efficacy of the combined vector vaccine Sputnik V in patients with CLL. Here, we analyzed and compared the magnitudes of the antibody and T cell responses after vaccination with the Sputnik V vaccine among healthy donors and individuals with CLL with different statuses of preexposure to coronavirus. We found that vaccination of the COVID-19-recovered individuals resulted in the boosting of pre-existing immune responses in both healthy donors and CLL patients. However, the COVID-19-naïve CLL patients demonstrated a considerably lower antibody response than the healthy donors, although they developed a robust T cell response. Regardless of the previous infection, the individuals over 70 years old demonstrated a decreased response to vaccination, as did those receiving anti-CD20 therapy. In summary, we showed that Sputnik V, like other vaccines, did not induce a robust antibody response in individuals with CLL; however, it provided for the development of a significant anti-COVID-19 T cell response.

Immunogenicity and risks associated with impaired immune responses following SARS-CoV-2 vaccination and booster in hematologic malignancy patients: an updated meta-analysis

Patients with hematologic malignancies (HM) have demonstrated impaired immune responses following SARS-CoV-2 vaccination. Factors associated with poor immunogenicity remain largely undetermined. A literature search was conducted using PubMed, EMBASE, Cochrane, and medRxiv databases to identify studies that reported humoral or cellular immune responses (CIR) following complete SARS-CoV-2 vaccination. The primary aim was to estimate the seroconversion rate (SR) following complete SARS-CoV-2 vaccination across various subtypes of HM diseases and treatments. The secondary aims were to determine the rates of development of neutralizing antibodies (NAb) and CIR following complete vaccination and SR following booster doses. A total of 170 studies were included for qualitative and quantitative analysis of primary and secondary outcomes. A meta-analysis of 150 studies including 20,922 HM patients revealed a pooled SR following SARS-CoV-2 vaccination of 67.7% (95% confidence interval [CI], 64.8-70.4%; I2 = 94%). Meta-regression analysis showed that patients with lymphoid malignancies, but not myeloid malignancies, had lower seroconversion rates than those with solid cancers (R2 = 0.52, P < 0.0001). Patients receiving chimeric antigen receptor T-cells (CART), B-cell targeted therapies or JAK inhibitors were associated with poor seroconversion (R2 = 0.39, P < 0.0001). The pooled NAb and CIR rates were 52.8% (95% CI; 45.8-59.7%, I2 = 87%) and 66.6% (95% CI, 57.1-74.9%; I2 = 86%), respectively. Approximately 20.9% (95% CI, 11.4-35.1%, I2 = 90%) of HM patients failed to elicit humoral and cellular immunity. Among non-seroconverted patients after primary vaccination, only 40.5% (95% CI, 33.0-48.4%; I2 = 87%) mounted seroconversion after the booster. In conclusion, HM patients, especially those with lymphoid malignancies and/or receiving CART, B-cell targeted therapies, or JAK inhibitors, showed poor SR after SARS-CoV-2 vaccination. A minority of patients attained seroconversion after booster vaccination. Strategies to improve immune response in these severely immunosuppressed patients are needed.