Immunologic consequences of chemotherapy for ovarian cancer: impaired responses to the influenza vaccine

Immunogenicity of an adjuvanted broadly active influenza vaccine in immunocompromised and diverse populations

Influenza virus outbreaks are a major burden worldwide each year. Current vaccination strategies are inadequate due to antigenic drift/shift of the virus and the elicitation of low immune responses. The use of computationally optimized broadly reactive antigen (COBRA) hemagglutinin (HA) immunogens subvert the constantly mutating viruses; however, they are poorly immunogenic on their own. To increase the immunogenicity of subunit vaccines such as this, adjuvants can be delivered with the vaccine. For example, agonists of the stimulator of interferon genes (STING) have proven efficacy as vaccine adjuvants. However, their use in high-risk populations most vulnerable to influenza virus infection has not been closely examined. Here, we utilize a vaccine platform consisting of acetalated dextran microparticles loaded with COBRA HA and the STING agonist cyclic GMP-AMP. We examine the immunogenicity of this platform in mouse models of obesity, aging, and chemotherapy-induced immunosuppression. Further, we examine vaccine efficacy in collaborative cross mice, a genetically diverse population that mimics human genetic heterogeneity. Overall, this vaccine platform had variable efficacy in these populations supporting work to better tailor adjuvants to specific populations.

Boosting In-Vivo Anti-Tumor Immunity with an Oral Microparticulate Breast Cancer Vaccine and Low-Dose Cyclophosphamide

Tumor cells express antigens that should induce immune-mediated rejection; however, spontaneous rejection of established tumors is rare. Recent evidence suggests that patients suffering from cancer exhibit an elevation in regulatory T cells population, a subset of CD4+ T cells, which suppress tumor recognition and elimination by cytotoxic T cells. This study investigates immunotherapeutic strategies to overcome the immunosuppressive effects exerted by regulatory T cells. A novel immunotherapeutic strategy was developed by simultaneous administration of oral microparticulate breast cancer vaccines and cyclophosphamide, a regulatory T cell inhibitor. Breast cancer vaccine microparticles were prepared by spray drying, and administered orally to female mice inoculated with 4TO7 murine breast cancer cells in combination with a low dose of intraperitoneally administered cyclophosphamide. Mice receiving the combination of vaccine microparticles and cyclophosphamide exhibited maximal tumor regression and the highest survival rate compared with the control groups. This study highlights the importance of cancer vaccination along with regulatory T cell depletion in cancer therapy, and suggests that a low dose of cyclophosphamide that specifically and significantly depletes regulatory T cells may be a highly effective immunotherapeutic strategy for the treatment of cancer.

Modulation of immunosuppressant drug treatment to improve SARS-CoV-2 vaccine efficacy in mice

The COVID-19 pandemic dramatically demonstrated the need for improved vaccination strategies and therapeutic responses to combat infectious diseases. However, the efficacy of vaccines has not yet been demonstrated in combination with commonly used immunosuppressive drug regimens. We sought to determine how common pharmaceutical drugs used in autoimmune disorders can alter immune responses to the SARS-CoV-2 spike protein vaccination. We treated mice with five immunosuppressant drugs (cyclophosphamide, leflunomide, methotrexate, methylprednisolone, and mycophenolate mofetil), each with various mechanisms of action prior to and following immunization with SARS-CoV-2 spike protein. We assessed the functionality of antibody responses to spike protein and compared immune cell populations in mice that received no treatment with those that received continuous or temporarily suspended immune suppressive therapy. All tested immunosuppressants significantly reduced the antibody titers in serum and functional antibody response against SARS-CoV-2 spike protein in immunized mice. Temporarily halting selected immunosuppressants (methylprednisolone and methotrexate, but not cyclophosphamide) improved antibody responses significantly. Through proof-of-principle experiments utilizing a mouse model, we demonstrated that immune suppression in autoimmune disorders through pharmaceutical treatments may impair vaccine response to SARS-CoV-2, and temporary suspension of immunosuppressant treatment may be necessary to mount an effective antibody vaccine response. This work provides feasibility for future clinical assessment of the impact of immunosuppressants on vaccine efficacy in humans.

B-Cell Immunophenotyping to Predict Vaccination Outcome in the Immunocompromised - A Systematic Review

Vaccination is the most effective measure to prevent infections in the general population. Its efficiency strongly depends on the function and composition of the immune system. If the immune system lacks critical components, patients will not be fully protected despite a completed vaccination schedule. Antigen-specific serum immunoglobulin levels are broadly used correlates of protection. These are the products of terminally differentiated B cells - plasma cells. Here we reviewed the literature on how aberrancies in B-cell composition and function influence immune responses to vaccinations. In a search through five major literature databases, 6,537 unique articles published from 2000 and onwards were identified. 75 articles were included along three major research lines: extremities of life, immunodeficiency and immunosuppression. Details of the protocol can be found in the International Prospective Register of Systematic Reviews [PROSPERO (registration number CRD42021226683)]. The majority of articles investigated immune responses in adults, in which vaccinations against pneumococci and influenza were strongly represented. Lack of baseline information was the most common reason of exclusion. Irrespective of study group, three parameters measured at baseline seemed to have a predictive value in assessing vaccine efficacy: (1) distribution of B-cell subsets (mostly a reduction in memory B cells), (2) presence of exhausted/activated B cells, or B cells with an aberrant phenotype, and (3) pre-existing immunological memory. In this review we showed how pre-immunization (baseline) knowledge of circulating B cells can be used to predict vaccination efficacy. We hope that this overview will contribute to optimizing vaccination strategies, especially in immunocompromised patients.

The Deadly Duo of COVID-19 and Cancer!

As of September 19, 2020, about 30 million people have been infected with the novel corona virus disease 2019 (COVID-19) globally, and the numbers are increasing at an alarming rate. The disease has a tremendous impact on every aspect of life, but one of the biggest, related to human health and medical sciences, is its effect on cancer. Nearly 2% of the total COVID-19 patients prior to May 2020 had cancer, and the statistics are quite frightening as the patient can be referred to as "doubly unfortunate" to suffer from cancer with the added misery of infection with COVID-19. Data regarding the present situation are scarce, so this review will focus on the deadly duo of COVID-19 and cancer. The focus is on molecular links between COVID-19 and cancer as inflammation, immunity, and the role of angiotensin converting enzyme 2 (ACE2). Complications may arise or severity may increase in cancer patients due to restrictions imposed by respective authorities as an effort to control COVID-19. The impact may vary from patient to patient and factors may include a delay in diagnosis, difficulty managing both cancer therapy and COVID-19 at same time, troubles in routine monitoring of cancer patients, and delays in urgent surgical procedures and patient care. The effect of anti-cancer agents on the condition of cancer patients suffering from COVID-19 and whether these anti-cancer agents can be repurposed for effective COVID-19 treatment are discussed. The review will be helpful in the management of deadly duo of COVID-19 and cancer.

Comorbidities and inflammation associated with ovarian cancer and its influence on SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide is a major public health concern. Cancer patients are considered a vulnerable population to SARS-CoV-2 infection and may develop several COVID-19 symptoms. The heightened immunocompromised state, prolonged chronic pro-inflammatory milieu coupled with comorbid conditions are shared in both disease conditions and may influence patient outcome. Although ovarian cancer (OC) and COVID-19 are diseases of entirely different primary organs, both diseases share similar molecular and cellular characteristics in their microenvironment suggesting a potential cooperativity leading to poor outcome. In COVID-19 related cases, hospitalizations and deaths worldwide are lower in women than in males; however, comorbidities associated with OC may increase the COVID-19 risk in women. The women at the age of 50-60 years are at greater risk of developing OC as well as SARS-CoV-2 infection. Increased levels of gonadotropin and androgen, dysregulated renin-angiotensin-aldosterone system (RAAS), hyper-coagulation and chronic inflammation are common conditions observed among OC and severe cases of COVID-19. The upregulation of common inflammatory cytokines and chemokines such as tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-2, IL-6, IL-10, interferon-γ-inducible protein 10 (IP-10), granulocyte colony-stimulating factor (G-CSF), monocyte chemoattractant protein-1 (MCP-1), macrophage colony-stimulating factor (M-CSF), among others in the sera of COVID-19 and OC subjects suggests potentially similar mechanism(s) involved in the hyper-inflammatory condition observed in both disease states. Thus, it is conceivable that the pathogenesis of OC may significantly contribute to the potential infection by SARS-CoV-2. Our understanding of the influence and mechanisms of SARS-CoV-2 infection on OC is at an early stage and in this article, we review the underlying pathogenesis presented by various comorbidities of OC and correlate their influence on SARS-CoV-2 infection.

Seasonal influenza vaccination among cancer patients: A systematic review and meta-analysis of the determinants

Cancer patients are among high-risk individuals for whom seasonal influenza vaccine (SIV) is recommended, but rates of vaccination in this subpopulation remain suboptimal; even in jurisdictions with universal influenza vaccination programs. We sought to summarize the evidence to better understand the determinants of SIV uptake (vaccine receipt) among cancer patients. We searched MEDLINE, Embase, and CINAHL from 2000 to February 12, 2020, focusing on articles on the determinants of seasonal influenza vaccination among cancer patients, published in English. Study selection was conducted independently by 2 reviewers. One reviewer extracted data from the included studies and another reviewer checked the extracted data for errors. Outcomes were sociodemographic and health-related factors. We pooled adjusted results from studies using the inverse variance, random-effects method, and reported the odds ratios (OR) and their 95% confidence intervals (CI). Out of 2664 citations, 10 studies (mostly from USA and South Korea) met our eligibility criteria. Overall, being older (OR 2.23, 95% CI 1.46-3.38; I² 92.3%, [6 studies]), a nonsmoker (1.43, 1.32-1.51; I² 0%, [4 studies]), having a chronic illness (1.18, 1.07-1.29; I² 15.7%, [5 studies]), having had a medical check-up in the past year (1.75, 1.65-1.86; I² 0%, [2 studies]), and having health insurance (1.39, 1.13-1.72; I² 21.8%, [3 studies]) were associated with increased SIV uptake. Compared with being African-American, being Caucasian was also associated with increased SIV uptake (1.79, 1.47-2.13; I² 10.7%, [3 studies]). Limited evidence suggests seasonal influenza vaccination among cancer patients may be determined by some sociodemographic and health-related factors.

The Impact of COVID-19 on Cancer Risk and Treatment

Millions of people are being infected with COVID-19 around the globe. Though the majority of them will recover, cancer patients remain at a higher risk to SARS-CoV-2 infection and its related severe outcomes. Understanding how viruses contribute to human cancers provides us with new opportunities for preventing or treating virus-associated cancers. However, a limited amount of research has been done to date in the context of how viral infections impact cancer at the cellular level and vice versa. Therefore, in light of the COVID-19 global infection, this review highlights the need for better understanding of the biology of viral infections in cancer patients, to enable novel therapies to co-target viral infections and cancer.

Efficacy of influenza vaccine (Fluvax) in cancer patients on treatment: a prospective single arm, open-label study

PURPOSE

Influenza virus infection has significant morbidity and mortality in patients with medical co-morbidities who are also immunosuppressed. The efficacy of the seasonal influenza vaccine has not been well studied in patients receiving chemotherapy. We assessed the efficacy of seasonal influenza vaccine in patients with non-haematological malignancy on active treatment (chemotherapy and targeted therapy).

METHODS

A prospective single arm, open label study with 53 patients with non-haematological cancers recruited during the 2011 and 2012 influenza seasons. Participants had one dose of 2011/2012 trivalent vaccine containing strains A/California/7/2009(H1N1), A/Perth/16/2009 (H3N2) and B/Brisbane/60/2008 (Fluvax) prior to or in-between treatment cycles. Haemagglutination inhibition antibody (HIA) titres in serum were measured at baseline 3, 6 and 24 weeks. Primary endpoint: seroconversion rate (SCR) at 3 weeks. Secondary endpoints: late SCR at 6 weeks. rate of sustained sero-protection titres (SPR) at 24 weeks. Seroconversion was defined as postvaccination ≥ 4-fold increase in HIA titre and sero-protection defined as a HIA ≥ 1:40.

RESULTS

The SCR at 3 weeks were 35%, 30% and 22.5% to the H1N1, H3N2 and B/Bris strains, respectively. There were no new cases of late SC at 6 weeks or 24 weeks. The SPR at 3 weeks were 72.5%, 65% and 40%, respectively, to H1N1, H3N2 and B/Bris. The SPR at 24 weeks to H1N1, H3N2 and B/Bris were 40%, 52.5% and 17.5%, respectively.

CONCLUSIONS

Patients on various solid tumour treatments achieve sero-protection rate congruent with the general population. The sero-protection HIA titres were not sustained at 24 weeks postvaccination.

Influenza vaccination in adult patients with solid tumours treated with chemotherapy

Patients with solid tumours receiving chemotherapy are at risk for influenza complications. Yearly influenza vaccination is recommended to patients treated with chemotherapy. However, adherence to vaccination is low, most likely due to lack of data on efficacy, optimal timing and safety of vaccination. There is scarce evidence for the effectiveness of the influenza vaccine in adult patients with solid tumours and chemotherapy on reduction of pneumonia, decreased mortality and fewer interruptions of oncological treatment. A review of 20 non-randomised serological studies in adult patients with different cancer types and chemotherapy provides insight in general trends of response to vaccination. Overall, the magnitude of the antibody response after influenza vaccination (i.e. seroconversion) can be lower than in healthy controls, but the majority of patients with solid tumours is able to mount a timely, protective immunological response (i.e. seroprotection) regardless of chemotherapy schedule, similar to healthy controls. Small sample sizes, patient heterogeneity and lack of comparable study designs limit more specific recommendations related to cancer type and optimal timing of vaccination. The inactivated influenza vaccine is safe to administer to immunosuppressed patients; side-effects are similar to those in healthy individuals. Although vaccination before start of chemotherapy is preferred to ensure optimal protection in adults with solid tumours, also vaccination during chemotherapy can reduce influenza-related complications considering the overall trends in serological response. Given the increased morbidity and mortality of influenza, influenza vaccination should be advocated as an inexpensive and safe preventive measure in patients with solid tumours receiving chemotherapy.

Cancer Vaccines in Ovarian Cancer: How Can We Improve?

Epithelial ovarian cancer (EOC) is one important cause of gynecologic cancer-related death. Currently, the mainstay of ovarian cancer treatment consists of cytoreductive surgery and platinum-based chemotherapy (introduced 30 years ago) but, as the disease is usually diagnosed at an advanced stage, its prognosis remains very poor. Clearly, there is a critical need for new treatment options, and immunotherapy is one attractive alternative. Prophylactic vaccines for prevention of infectious diseases have led to major achievements, yet therapeutic cancer vaccines have shown consistently low efficacy in the past. However, as they are associated with minimal side effects or invasive procedures, efforts directed to improve their efficacy are being deployed, with Dendritic Cell (DC) vaccination strategies standing as one of the more promising options. On the other hand, recent advances in our understanding of immunological mechanisms have led to the development of successful strategies for the treatment of different cancers, such as immune checkpoint blockade strategies. Combining these strategies with DC vaccination approaches and introducing novel combinatorial designs must also be considered and evaluated. In this review, we will analyze past vaccination methods used in ovarian cancer, and we will provide different suggestions aiming to improve their efficacy in future trials.