Chronic vaccination with a therapeutic EGF-based cancer vaccine: a review of patients receiving long lasting treatment

Safety and effectiveness of CIMAvax-EGF administered in community polyclinics

In spite of the advances in immunotherapy and targeted therapies, lung cancer continues to be the leading cause of cancer-related death. The epidermal growth factor receptor is an established target for non-small cell lung cancer (NSCLC), and its overactivation by the ligands can induce accelerated proliferation, angiogenesis, and metastasis as well as proinflammatory or immunosuppressive signals. CIMAvax-EGF is an epidermal growth factor (EGF)-depleting immunotherapy that is approved for the treatment of NSCLC patients in Cuba. The study was designed as a phase IV trial to characterize the safety and effectiveness of CIMAvax-EGF in advanced NSCLC patients treated in 119 community polyclinics and 24 hospitals. CIMAvax-EGF treatment consisted of four bi-weekly doses followed by monthly boosters. Overall, 741 NSCLC patients ineligible for further cancer-specific treatment were enrolled. CIMAvax-EGF was safe, and the most common adverse events consisted of mild-to-moderate injection site reactions, fever, chills, tremors, and headache. For patients completing the loading doses, the median survival was 9.9 months. For individuals achieving at least stable disease to the frontline and completing vaccination induction, the median survival was 12 months. Most of the functional activities and symptoms evaluated through the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 questionnaire improved over time. In conclusion, this real-world trial demonstrated that CIMAvax-EGF was safe and effective in patients who were vaccinated in the maintenance scenario. A larger effect was seen in subjects with poor prognosis like those with squamous tumors and high EGF levels. Remarkably, this community-based intervention was very important because it demonstrated the feasibility of treating advanced lung cancer patients with active immunotherapy in primary care institutions. In addition to CIMAvax-EGF, patients received supportive care at the community clinic. Vaccine administration by the family doctors at the polyclinics reduced the patients' burden on the medical oncology services that continued providing chemotherapy and other complex therapies. We conclude that community polyclinics constitute the optimal scenario for administering those cancer vaccines that are safe and require prolonged maintenance in patients with advanced cancer, despite the continuous deterioration of their general condition.

Clinical trial registration

https://rpcec.sld.cu/trials/RPCEC00000205-En, identifier RPCEC00000205.

Associations among cytokines, EGF and lymphocyte subpopulations in patients diagnosed with advanced lung cancer

Aging is considered the single most significant risk factor for the majority of common malignances including lung cancer. Together immunosenescence, changes occurring with aging in the immune system, and inflammaging, characterizes by a chronic, subclinical accumulation of pro-inflammatory factors, are suggested to stand at the origin of most of the diseases of the elderly, such as cancer. The aim of this study was to determine associations among lymphocyte subpopulations, pro-inflammatory cytokines and epidermal growth factor (EGF) in patients diagnosed with non-small cell lung cancer (NSCLC). Forty-six advanced NSCLC patients were enrolled. Sixteen patients with newly diagnosed and before treatment and 30 patients after first-line platinum-based chemotherapy. Peripheral blood subpopulations were studied by flow cytometry and serum concentrations of soluble factors by ELISA. The frequency of naïve CD4⁺ T cells, naïve B cells and central memory CD8⁺ T cells were significantly lower in NSCLC patients after chemotherapy, while effector memory CD4⁺ T cells and terminally differentiated CD8⁺ T cells were significantly higher. IL-1β and TNFα significantly correlated among them before and after platinum-based chemotherapy. Terminally differentiated T cells expressing CD57⁺ significantly correlated with TNFα and IL-1β. For the first time, associations between EGF serum levels and terminally differentiated CD4⁺ T cells, and memory B cells were detected. This study confirms the association among terminally differentiated lymphocytes and pro-inflammatory cytokines in patients diagnosed with lung cancer, reinforcing the interconnection between terminally differentiated lymphocytes and pro-inflammatory cytokines. Clinical trial registration number: RPCEC00000205, http://registroclinico.sld.cu/.

Recombinant virus-like particles presenting IL-33 successfully modify the tumor microenvironment and facilitate antitumor immunity in a model of breast cancer

Recently, interleukin (IL)-33 has been closely associated with a variety of clinical cancers. IL-33 presents both protumorigenic, and less frequently, antitumorigenic functions depending on disease conditions. IL-33 signaling appears to be a possible target for the treatment of applicable tumor diseases. This study aimed to develop an effective approach to intervene in IL-33 functioning in tumors and reveal the immunotherapeutic potential of anti-IL-33 active immunization. Recombinant truncated hepatitis B virus core antigen (HBcAg), presenting mature IL-33 molecules on the surface of virus-like particles (VLPs), was prepared and used to immunize BALB/c mice in a model of murine 4T1 breast cancer. The immunization was performed through either a preventive or therapeutic strategy in two separate studies. Anti-IL-33 immunization with VLPs elicited a persistent and highly titrated specific antibody response and significantly suppressed orthotopic tumor growth in the preventive study and lung metastasis in both studies. The underlying mechanisms might include promoting tumor-specific Th1 and CTL-mediated cellular responses and the expression of the effector molecule interferon-γ (IFN-γ), suppressing T-helper type 2 (Th2) responses, and significantly reducing the infiltration of immunosuppressive Treg (regulatory T) cells and myeloid-derived suppressor cells (MDSCs) into tumor tissues in the immunized mice. In conclusion, anti-IL-33 active immunization employing recombinant VLPs as an antigen delivery platform effectively modified the tumor microenvironment and promoted antitumor immunity, indicating the potential of this approach as a new and promising immunotherapeutic strategy for the treatment of cancers where IL-33 plays a definite protumorigenic role. STATEMENT OF SIGNIFICANCE: Interleukin (IL)-33 is closely associated with a variety of clinical cancers. IL-33 signaling appears to be a possible target for the treatment of applicable tumor diseases. Recombinant truncated hepatitis B virus core antigen (HBcAg), presenting mature IL-33 molecules on the surface of virus-like particles (VLPs), was prepared and used to immunize BALB/c mice in a model of murine 4T1 breast cancer. The immunization was performed through either a preventive or therapeutic strategy in two separate studies. Anti-IL-33 immunization with VLPs elicited a persistent and highly titrated specific antibody response and significantly suppressed orthotopic tumor growth and lung metastasis in both studies. Furthermore, anti-IL-33 active immunization employing recombinant VLPs as an antigen delivery platform effectively modified the tumor microenvironment and promoted antitumor immunity, indicating its potential as a new and promising immunotherapeutic strategy for the treatment of cancers where IL-33 plays a definite protumorigenic role.

Enhanced anti-tumor immunotherapy by dissolving microneedle patch loaded ovalbumin

The skin is a very suitable organ for the induction of immune responses to vaccine antigens. Antigen delivery systems to the skin by needle and syringe directly deposit the antigen into the epidermal-dermal compartment, one of the most immunocompetent sites due to the presence of professional antigen-presenting cells aimed at the induction of antigen-specific T cells. In this study, we analyzed the amount of ovalbumin as an antigen delivered to the skin by a microneedle. When ovalbumin protein as an antigen was delivered to the skin of mice using a dissolving microneedle, it induced an immune response through the enhanced proliferation and cytokines production by the splenocytes and lymph nodes. Also, it effectively increased the ovalbumin-specific CD8⁺ T cell and CD4⁺ T cell population and induced an ovalbumin-specific CTL response against the graft of ovalbumin-expressing EG7 tumor cells in the immunized mice. Also, we identified the inhibition of tumor growth and prevention of tumor formation in the context of the therapeutic and prophylactic vaccine, respectively through EG-7 tumor mouse model. Finally, these data show the potential of patches as attractive antigen delivery vehicles.

Characteristics of the specific humoral response in patients with advanced solid tumors after active immunotherapy with a VEGF vaccine, at different antigen doses and using two distinct adjuvants

Background

CIGB-247, a VSSP-adjuvanted VEGF-based vaccine, was evaluated in a phase I clinical trial in patients with advanced solid tumors (CENTAURO). Vaccination with the maximum dose of antigen showed an excellent safety profile, exhibited the highest immunogenicity and was the only one showing a reduction on platelet VEGF bioavailability. However, this antigen dose level did not achieve a complete seroconversion rate in vaccinated patients. These clinical results led us to the question whether a “reserve” of untapped immune response potential against VEGF could exist in cancer patients. To address this matter, CENTAURO-2 clinical trial was conducted where antigen and VSSP dose scale up were studied, and also incorporated the exploration of aluminum phosphate as adjuvant. These changes were made with the aim to increase immune response against VEGF.

Results

The present study reports the characterization of the humoral response elicited by CIGB-247 from the combining of different antigen doses and adjuvants. Cancer patients were immunologically monitored for approximately 1 year. Vaccination with different CIGB-247 formulations exhibited a very positive safety profile. Cancer patients developed IgM, IgG or IgA antibodies specific to VEGF. Elicited polyclonal antibodies had the ability to block the interaction between VEGF and its receptors, VEGFR1 and VEGFR2. The highest humoral response was detected in patients immunized with 800 μg of antigen + 200 μg of VSSP. Off-protocol long-term vaccination did not produce negative changes in humoral response.

Conclusions

Vaccination with a human VEGF variant molecule as antigen in combination with VSSP or aluminum phosphate is immunogenic. The results of this study could contribute to the investigation of this vaccine therapy in an adequately powered efficacy trial.

Trial registration

Trial registration number: RPCEC00000155. Cuban Public Clinical Trial Registry. Date of registration: June 06, 2013. Available from: http://registroclinico.sld.cu/.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-017-0222-z) contains supplementary material, which is available to authorized users.

An enzyme immunoassay for determining epidermal growth factor (EGF) in human serum samples using an ultramicroanalytical system

Human epidermal growth factor is a small peptide consisting of 53 amino acid residues, which stimulates cell proliferation and is associated with several human carcinomas. A simple sandwich-type ultramicroELISA assay (UMELISA), based on the advantages of high affinity reaction between streptavidin and biotin has been developed for the measurement of EGF in human serum samples. Strips coated with a high affinity monoclonal antibody directed against EGF are used as solid phase, to ensure the specificity of the assay. The EGF assay was completed in 18 hr, with a measuring range of 39-2500 pg/mL. The intra- and inter-assay coefficients of variation were 4.4-7.3% and 0-5.1%, respectively, depending on the EGF concentrations evaluated. Percentage recovery ranged from 96-104%. Regression analysis showed a good correlation with the commercially available Human EGF Immunoassay Quantikine^® ELISA kit (n = 130, r = 0.92, P < 0.01). The analytical performance characteristics of our UMELISA EGF endorse its use for the quantification of EGF in human serum samples.

Insight to drug delivery aspects for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide in human beings. Surgery, chemotherapy, radiotherapy and targeted therapies are the conventional four approaches which are currently used for the treatment of CRC. The site specific delivery of chemotherapeutics to their site of action would increase effectiveness with reducing side effects. Targeted oral drug delivery systems based on polysaccharides are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific drug delivery to colon increases its concentration at the target site, and thus requires a lower dose and hence abridged side effects. Some novel therapies are also briefly discussed in article such as receptor (epidermal growth factor receptor, folate receptor, wheat germ agglutinin, VEGF receptor, hyaluronic acid receptor) based targeting therapy; colon targeted proapoptotic anticancer drug delivery system, gene therapy. Even though good treatment options are available for CRC, the ultimate therapeutic approach is to avert the incidence of CRC. It was also found that CRCs could be prevented by diet and nutrition such as calcium, vitamin D, curcumin, quercetin and fish oil supplements. Immunotherapy and vaccination are used nowadays which are showing better results against CRC.

Advances and Prospects in Cancer Immunotherapy

Cancer immunotherapy is a promising and effective treatment modality for patients with cancers. Cytokine, anticytokine, and antibody therapies appear to be effective in treating various forms of cancer. The human papillomavirus vaccine is protective for cervical cancer, and this discovery has paved the way to the development of cancer vaccines for other forms of virus-associated cancers such as liver cancer and Merkel cell carcinoma. Clinical trials have demonstrated that adoptive cell therapy using tumor-infiltrating lymphocytes can induce tumor regression in approximately 75% of metastatic melanoma patients, suggesting the possibility of using similar technique to effectively treat breast, lung, and renal cancers in the near future. Besides, genetically engineered T cells transduced with genes encoding specific T cell receptors and chimeric antigen receptors have been shown effective in the treatment of cancer patients. These studies suggest that combination therapies are superior choices in cancer immunotherapy for patients.

Effect of blockade of the EGF system on wound healing in patients vaccinated with CIMAvax® EGF

Background

The epidermal growth factor receptor (EGFR) signaling system is frequently unbalanced in human malignancies due to increased ligand production, receptor overexpression, receptor mutations, and/or cross-talk with other receptor systems. For this reason, the EGFR is an attractive target for anticancer therapy. The epidermal growth factor also plays an important role in regulating multiple facets of cutaneous wound healing, including inflammation, wound contraction, proliferation, migration, and angiogenesis. In the Center of Molecular Immunology, a cancer vaccine is produced (CIMAvax® EGF) that blocks the binding of EGF to its receptor. This blockade causes a significant inverse association between the anti-EGF antibody titers and EGF concentration. Around 1,500 patients with non-small cell lung cancer have been treated, showing that this vaccine is safe, immunogenic, increases survival and improves quality of life. Taking into account the therapeutic benefits of CIMAvax® EGF vaccination and the role of EGF-EGFR system in the wound healing process, we decided to conduct a retrospective research with the aim of determining the effect to the CIMAvax® EGF vaccine on the wound healing process in patients undergoing surgical treatment.

Methods

Medical records of 452 vaccinated patients were reviewed and only six patients receiving surgical treatment were identified. Further information about these six patients was obtained from source documents, including medical records and operative reports using an observational list that included different variables. Post-surgical wound healing complications were identified using the National Cancer Institute Common Toxicity Criteria for Adverse Events (NCI-CTC) version 3.0.

Results

None of the six patients operated on presented adverse events related to the wound healing, that is to say, no wound dehiscence, wound infection, delayed wound healing, fistula formation, abscess formation or hemorrhage/bleeding associated with surgery during treatment with CIMAvax® EGF occurred.

Conclusions

These results suggest that the use of CIMAvax® EGF does not produce a deleterious effect in the wound healing process.

Challenges and opportunities for cancer vaccines in the current NSCLC clinical scenario

This review is aimed to focus on NSCLC as an emerging and promising model for active immunotherapy and the challenges for its inclusion in the current clinical scenario. Cancer vaccines for NSCLC have been focused as a therapeutic option based on the identification of a tumor hallmark and the active immunization with the related molecules that triggers cellular and/or humoral responses that consequently destroy or delay the rate of malignant progression. This therapeutic intervention in an established disease state has been aimed to impact into prolonging patient´s survival with ethically accepted quality of life. Understanding of relationship between structure and function in cancer vaccines is essential to interpret their opportunities to impact into prolonging survival and increasing quality of life in cancer patients. It is widely accepted that the failure of the cancer vaccines in the NSCLC scenario is related with its introduction in the advanced disease stages and poor performance status of the patients due to the combination of the tumor induced immunosuppression with the immune senescence. Despite first, second and emerging third line of onco-specific treatments the life expectancy for NSCLC patients diagnosed at advanced stages is surrounding the 12 months of median survival and in facts the today real circumstances are extremely demanding for the success inclusion of cancer vaccines as therapeutic choice in the clinical scenario. The kinetics of the active immunizations encompasses a sequential cascade of clinical endpoints: starting by the activation of the immune system, followed by the antitumor response and finalizing with the consequential impact on patients’ overall survival. Today this cascade of clinical endpoints is the backbone for active immunization assessment and moreover the concept of cancer vaccines, applied in the NSCLC setting, is just evolving as a complex therapeutic strategy, in which the opportunities for cancer vaccines start from the selection of the target cancer hallmark, followed by the vaccine formulation and its platforms for immune potentiating, also cover the successful insertion in the standard of care, the chronic administration beyond progression disease, the personalization based on predictors of response and the potential combination with other targeted therapies.

Effects of an epidermal growth factor receptor-based cancer vaccine on wound healing and inflammation processes in murine experimental models

Anti-epidermal growth factor receptor (EGFR) therapies have been proven clinically effective for a variety of epithelial tumours. Vaccination of mice with the extracellular domain (ECD) of autologous EGFR overcomes the tolerance to self-EGFR and has antimetastatic effect on EGFR+ tumour. Because EGF/EGFR-signalling plays an important role in the inflammation stage of wound healing, the main objective of this study was to explore the possible role of murine (m) EGFR-ECD vaccine in the croton-oil-induced ear oedema and wound healing process in mice as autologous experimental models, mimicking the possible post-surgical wound complication in patients treated with human EGFR-ECD/VSSP vaccine. Mice were intramuscularly immunised four times; biweekly with the mEGFR-ECD/VSSP/Mont. Seven days later, an 8 mm diameter, full-thickness skin wound was created on the back of each animal. Immunisation induced a strong specific humoral response against the mEGFR-ECD protein and a DTH dose-response curve but interestingly, animals treated with mEGFR-ECD/VSSP/Mont had similar inflammatory and healing speed responses compared to control ones. These data suggest that application of mEGFR-ECD/VSSP vaccine as a therapeutic approach in cancer patients could not elicit a poor healing process after surgery.

Therapeutic vaccination with an EGF-based vaccine in lung cancer: a step in the transition to a chronic disease

The trend of increased survival in advanced tumors suggests the possibility of the transformation of cancer into a chronic disease. That goal will require therapeutic weapons with low toxicity that can be used chronically. Here we summarize the development of a therapeutic vaccine consisting in recombinant EGF chemically linked to a protein from Neisseria meningitides. In mice, the vaccine elicited antibodies to self-EGF and had anti-tumor activity. Clinical trials have shown that the vaccine is also immunogenic and well tolerated in humans. The vaccination produced a decrease in plasma EGF concentration. Advanced lung cancer patients eliciting high antibody titers of EGF had better survival. The vaccine can be used long term and integrated with other treatment modalities.

Control of advanced cancer: the road to chronicity

Despite the recent trend toward a slight decrease in age-adjusted cancer mortality in some countries, crude mortality rates will continue to increase, driven by the demographic shift towards an aged population. Small molecules (small molecules and biologics) are not only a new therapeutic acquisition, but the tools of a more fundamental transition: the transformation of cancer from a rapidly fatal disease into a chronic condition. Antibodies and cancer vaccines can be used for a long time, even beyond progressive disease, and in aged patients, usually unfit for more aggressive conventional treatments. However, this transition to chronicity will require novel developmental guidelines adequate to this kind of drugs, for which optimal dose is not usually the maximal tolerated dose, pharmacokinetics does not define treatment schedule, and tumor shrinkage is not a good correlate of survival. The ongoing cancer immunotherapy program (including several monoclonal antibodies and therapeutic vaccines) at the Centre of Molecular Immunology can illustrate the issues to be addressed, both biological and social, along the path to transform advanced cancer into a chronic non-communicable disease compatible with years of quality life.