Anti-EGF antibodies as surrogate biomarkers of clinical efficacy in stage IIIB/IV non-small-cell lung cancer patients treated with an optimized CIMAvax-EGF vaccination schedule.

We previously reported that CIMAvax-EGF vaccine is safe, immunogenic and efficacious to treat advanced non-small-cell lung cancer (NSCLC) patients. A phase III trial was designed using an optimized immunization schedule. It included higher antigen dose and injections at multiple sites. Immune response and circulating biomarkers were studied in a subset of patients. EGF-specific antibody titers, IgG subclasses, peptide immunodominance and circulating biomarkers were assessed by ELISA. In vitro EGF-neutralization capacity of immune sera and EGF-IgG binding kinetics was evaluated by Western Blot and Surface Plasmon Resonance (SPR) technology, respectively. We show that CIMAvax-EGF elicited mainly IgG3/IgG4 antibodies at titers exceeding 1:4000 in 80% of vaccinated patients after 3 months of treatment. The EGF-specific humoral response was directed against the central region of the EGF molecule. For the first time, the kinetic constants of EGF-specific antibodies were measured evidencing affinity maturation of antibody repertoire up to month 12 of vaccination. Notably, the capacity of post-immune sera to inhibit EGFR phosphorylation significantly increased during the course of the immunization scheme and was related to clinical outcome (P = .013, log-rank test). Basal concentrations of EGF and TGFα in the serum were affected by EGF-based immunization. In conclusion, the CIMAvax-EGF vaccine induces an EGF-specific protective humoral response in a high percent of NSCLC vaccinated patients, the quantity and quality of which were associated with clinical benefit (clinical trial registration number: RPCEC00000161, http://registroclinico.sld.cu/). Abbreviations: EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; Ab: antibody; AR: amphiregulin; NSCLC: non-small-cell lung cancer; rhEGF: recombinant human epidermal growth factor; BSC: best supportive care; TGFα: tumor growth factor alpha; IL-8: interleukin 8; MAb: monoclonal antibody; SPR: surface plasmon resonance.

Differential effects of two therapeutic cancer vaccines on short- and long-term survival populations among patients with advanced lung cancer.

BACKGROUND: Progress in immunotherapy has revolutionized the treatment landscape for advanced lung cancer, with emerging evidence of patients experiencing long-term survivals. The goal of this study was to explore the existence of short- and long-term survival populations and to assess the effect of immunotherapy on them. METHODS: Data from two randomized, multicenter, controlled clinical trials was used to evaluate the effect of two therapeutic vaccines (anti-idiotypic vaccine VAXIRA and anti-EGF vaccine CIMAVAX) on survival curves in advanced non-small cell lung cancer patients. Data were fitted to Kaplan-Meier, standard Weibull survival, and two-component Weibull mixture models. Bayesian Information Criterion was used for model selection. RESULTS: VAXIRA did not modify, neither the fraction of patients with long-term survivals (0.18 in the control group v 0.19 with VAXIRA, P = .88), nor the median overall survival of the patients in the short-term survival subpopulation (6.8 v 7.8 months, P = .24). However, this vaccine showed great benefit for the patients belonging to the subpopulation of patients with long-term survival (33.8 v 76.6 months, P <.0001). CIMAVAX showed impact in the overall survival of both short- and long-term populations (6.8 v 8.8 months, P = .005 and 33.8 v 61.8 months, P = .007). It also increased the proportion of patients with long-term survival (from 0.18 to 0.28, P = .02). CONCLUSIONS: This study shows that therapeutic vaccines produce differential effects on short- and long-term survival populations and illustrates the application of advanced statistical methods to deal with the long-term evolution of patients with advanced lung cancer in the era of immunotherapy.

A Phase III Clinical Trial of the Epidermal Growth Factor Vaccine CIMAvax-EGF as Switch Maintenance Therapy in Advanced Non-Small Cell Lung Cancer Patients.

PURPOSE: EGFR is a well-validated target for patients with non-small cell lung cancer (NSCLC). CIMAvax-EGF is a therapeutic cancer vaccine composed of human recombinant EGF conjugated to a carrier protein and Montanide ISA51 as adjuvant. The vaccine is intended to induce antibodies against self EGFs that block EGF-EGFR interaction. EXPERIMENTAL DESIGN: To evaluate overall survival, safety, immunogenicity, and EGF concentration in serum after CIMAvax-EGF, a randomized phase III trial was done in patients with advanced NSCLC. Four to 6 weeks after first-line chemotherapy, 405 patients with stage IIIB/IV NSCLC were randomly assigned to a vaccine group, which received CIMAvax-EGF or a control group, treated with best supportive care. RESULTS: Long-term vaccination was very safe. Most frequent adverse reactions were grade 1 or 2 injection-site pain, fever, vomiting, and headache. Vaccination induced anti-EGF antibodies and decreased serum EGF concentration. In the safety population, median survival time (MST) was 10.83 months in the vaccine arm versus 8.86 months in the control arm. These differences were not significant according the standard log rank (HR, 0.82; P = 0.100), but according a weighted log rank (P = 0.04) that was applied once the nonproportionality of the HR was verified. Survival benefit was significant (HR, 0.77; P = 0.036) in the per-protocol setting (patients receiving at least four vaccine doses): MST was 12.43 months for the vaccine arm versus 9.43 months for the control arm. MST was higher (14.66 months) for vaccinated patients with high EGF concentration at baseline. CONCLUSIONS: Switch maintenance with CIMAvax-EGF was well tolerated and significantly increased MST of patients that completed induction vaccination. Baseline EGF concentration predicted survival benefit. Clin Cancer Res; 22(15); 3782-90. ©2016 AACR.

Therapeutic Targeting of CD6 in Autoimmune Diseases: A Review of Cuban Clinical Studies with the Antibodies IOR-T1 and Itolizumab.

The CD6 molecule is a pan T cell marker involved in T cell regulation. Although CD6 expression has been correlated with human autoimmune diseases, only a few therapeutic approaches are exploring this molecule as target in the clinic. The biological functions and mechanisms of actions of CD6 have not been definitively established. It is probable that this molecule plays a dual role as a modulator of intracellular signaling. Itolizumab is a humanized monoclonal antibody specific for human CD6, developed at the Center of Molecular Immunology in Havana, Cuba. Its parent murine antibody, the IOR-T1 mAb, had been obtained in the 80's at the Institute of Oncology and Radiology, also in Havana. This article provides an overview of the clinical data obtained in Cuban patients with autoimmune diseases who have been treated with IOR-T1 mAb or itolizumab. Furthermore, we discuss the possible mechanism of action of itolizumab basing the analysis on recent site mutagenesis and structural data, which, contrary to previous interpretations, points to a steric blocking of the CD6-CD166 interaction in the cellular context. Overall, the conducted clinical studies have demonstrated that itolizumab has favorable clinical effects and a safety profile when used as monotherapy in patients with rheumatoid arthritis and psoriasis. So far, in vitro and in vivo evidences indicate that itolizumab has immunomodulatory and anti-inflammatory effects. Hence, itolizumab represents a new therapeutic option for autoimmune diseases such as rheumatoid arthritis and psoriasis.

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.

A clinical exploratory study with itolizumab, an anti-CD6 monoclonal antibody, in patients with rheumatoid arthritis.

T cells are involved in the pathogenesis of rheumatoid arthritis (RA). CD6 is a co-stimulatory molecule, predominantly expressed on lymphocytes, that has been linked to autoreactive responses. The purpose of this study was to evaluate the safety, immunogenicity and preliminary efficacy of itolizumab, a humanized anti-CD6 monoclonal antibody, in patients with active rheumatoid arthritis. Fifteen patients were enrolled in a phase I, open-label, dose-finding study. Five cohorts of patients received a weekly antibody monotherapy with a dose-range from 0.1 to 0.8 mg/kg. Itolizumab showed a good safety profile, with no severe or serious adverse events reported so far. No signs or symptoms associated with immunosuppression were observed in the study. Objective clinical responses were achieved in more than 80% of patients after treatment completion, and these responses tend to be sustained afterwards. This clinical study constitutes the first evidence of the safety and positive clinical effect of a monotherapy using an anti-CD6 antibody in patients with rheumatoid arthritis.

Safety, immunogenicity and preliminary efficacy of multiple-site vaccination with an Epidermal Growth Factor (EGF) based cancer vaccine in advanced non small cell lung cancer (NSCLC) patients.

The prognosis of patients with advanced non small cell lung (NSCLC) cancer remains dismal. Epidermal Growth Factor Receptor is over-expressed in many epithelial derived tumors and its role in the development and progression of NSCLC is widely documented. CimaVax-EGF is a therapeutic cancer vaccine composed by human recombinant Epidermal Growth Factor (EGF) conjugated to a carrier protein, P64K from Neisseria Meningitides. The vaccine is intended to induce antibodies against self EGF that would block EGF-EGFR interaction. CimaVax-EGF has been evaluated so far in more than 1000 advanced NSCLC patients, as second line therapy. Two separate studies were compared to assess the impact of high dose vaccination at multiple anatomic sites in terms of immunogenicity, safety and preliminary efficacy in stage IIIb/IV NSCLC patients. In both clinical trials, patients started vaccination 1 month after finishing first line chemotherapy. Vaccination at 4 sites with 2.4 mg of EGF (high dose) was very safe. The most frequent adverse events were grade 1 or 2 injection site reactions, fever, headache and vomiting. Patients had a trend toward higher antibody response. The percent of very good responders significantly augmented and there was a faster decrease of circulating EGF. All vaccinated patients and those classified as good responders immunized with high dose at 4 sites, had a large tendency to improved survival.

Clinical development and perspectives of CIMAvax EGF, Cuban vaccine for non-small-cell lung cancer therapy.

INTRODUCTION: CIMAvax EGF is a therapeutic anticancer vaccine developed entirely in Cuba and licensed in Cuba for use in adult patients with stage IIIB/IV non-small-cell lung cancer (NSCLC). The vaccine is based on active immunotherapy by which an individual's immune response is manipulated to release its own effector antibodies (Abs) against the epidermal growth factor (EGF). OBJECTIVE: Review pre-clinical and clinical research conducted during development of CIMAvax EGF, primarily studies published by Cuban investigators in international peer-reviewed scientific journals. Methods An automated search for "vaccine" and "EGF" was conducted in PubMed, resulting in 17 articles published by Cuban authors between January 1, 1994 and September 30, 2009. Main findings were described and discussed, along with unpublished preliminary findings of an initial ongoing phase III clinical trial. RESULTS: Articles reviewed describe five phase I/II and one phase II clinical trials conducted in Cuba in 1995-2005. A non-controlled 1995-1996 study resulted in the earliest published scientific evidence of the feasibility of inducing an immune response against autologous EGF in patients with different advanced stage tumors. Subsequent controlled, randomized trials included patients with advanced stage (IIIB/IV) NSCLC. The 2 and 3rd phase I/II trials differentiated immunized patients as poor antibody responders (PAR) and good antibody responders (GAR), according to their anti-EGF antibody response, and confirmed greater immunogenicity with Montanide ISA 51 adjuvant in the vaccine formulation, as well as the benefits of low-dose cyclophosphamide treatment 72 hours before the first immunization. The 4th phase I/II trial found increased immunogenicity with an increased dose divided in 2 anatomical sites and also established correlation between Ab titers, serum EGF concentration and length of survival. In the first 4 phase I/II trials and the phase II trial, vaccine was administered after chemotherapy (ChTVV schedule). In the 5th phase I/III trial, longer survival and increased immunogenicity were achieved using a VChTV schedule and dividing the vaccine dose in 4 anatomical sites. The phase II clinical trial confirmed results of earlier studies as well as the mild-to-moderate adverse event profile associated with CIMAvax EGF Longer survival was observed in all vaccinated patients compared to controls, and the difference was significant (p < 0.05) in the group aged <60 years. CONCLUSIONS: CIMAvax EGF's benefits in earlier NSCLC stages and in other tumor locations, as well as in patients unfit for chemotherapy, need to be evaluated. Evidence of the vaccine's safety for chronic use also needs to be systemized.

Introducción CIMAvax EGF es una vacuna terapéutica contra el cáncer enteramente desarrollada en Cuba y licenciada en el país para su uso en pacientes adultos con cáncer de pulmón de células no pequeñas (CPCNP) en etapas IIIB/IV. La vacuna se basa en la inmunoterapia activa; o sea, manipula la respuesta inmune de un individuo para que genere sus propios anticuerpos efectores (Acs) contra el factor de crecimiento epidérmico (EGF). Objetivo Revisar los estudios clínicos y preclínicos realizados durante el desarrollo de CIMAvax EGF, principalmente los publicados por investigadores cubanos en revistas científicas internacionales arbitradas. Métodos Se efectuó una búsqueda automatizada en PubMed con el uso de las palabras claves "vacuna" y "EGF", que dio como resultado 17 artículos publicados por autores cubanos entre el 1 de enero de 1994 y el 30 de septiembre del 2009. Se describieron y discutieron los principales resultados, junto con los hallazgos preliminares no publicados aún de un ensayo clínico inicial fase III en ejecución. Resultados Los artículos revisados describen cinco ensayos clínicos fase I/II y uno fase II realizados en Cuba de 1995­2005. Un estudio no controlado de 1995­1996 fue la primera evidencia científicas de la factibilidad de inducir una respuesta inmune contra el EGF autólogo en pacientes con diferentes tumores en etapas avanzadas. Ensayos posteriores controlados y aleatorizados incluyeron pacientes con CPCNP en etapas avanzadas (IIIB/IV). En los ensayos segundo y tercero de fase I/ II, los pacientes inmunizados se diferenciaron en buenos respondedores (BR) y malos respondedores (MR) según las respuestas de anticuerpos contra el EGF y se conformó mayor inmunogenicidad al utilizar el adyuvante Montanide ISA 51 en la formulación vacunal, así como los beneficios del tratamiento de ciclofosfamida a baja dosis 72 horas antes de la primera inmunización. En el cuarto ensayo fase I/II se encontró un aumento de la inmunogenicidad con el aumento de la dosis, dividida en dos sitios anatómicos, y además se estableció la correlación entre los títulos de Acs, la concentración de EGF sérico y la supervivencia. En los primeros cuatro ensayos fase I/II, la vacuna se administró después de la quimioterapia (esquema QVV). En el quinto ensayo fase I/II, se lograron mayor supervivencia e inmunogenicidad utilizando un esquema VQV y dividiendo la dosis vacunal en cuatro sitios anatómicos. El ensayo clínico de fase II conforrmó los resultados de los estudios anteriores, así como un perfil de eventos adversos leves a moderados asociados a CIMAvax EGF. Se observó mayor supervivencia en todos los pacientes vacunados en comparación con los controles y la diferencia fue estadísticamente significativa (p <0.05) en el grupo de <60 años. Conclusiones Es necesario evaluar los beneficios de CIMAvax EGF en etapas tempranas del CPCNP y en otras localizaciones tumorales, así como en los pacientes no aptos para recibir quimioterapia. La evidencia de que la vacuna es segura para uso mantenido también debe ser sistematizada. Palabras clave Factor de crecimiento epidérmico, receptor del EGF, cáncer de pulmón de células no pequeñas, tratamiento vacunal, inmunoterapia, vacunas oncológicas

Priming and boosting determinants on the antibody response to an Epidermal Growth Factor-based cancer vaccine.

Epidermal Growth Factor chemically conjugated to P64k carrier protein from Neisseria meningitidis emulsified in Montanide ISA 51 adjuvant is a cancer vaccine under clinical evaluation. We explored the influence of priming and boosting variables on the antibody response in mice. An apparently low dose fractionated in multiple anatomical sites at priming accelerated the induction and enhanced the maximal antibody response, with a long-lasting effect. Moreover, shortening the boosting time reduces the antibody persistence. Repeatedly boosting shift subjects to good antibody-responders, maintaining the epitope immunodominance. We conclude that optimizing immunopharmacological determinants contribute to an earlier, stronger and prolonged anti-EGF antibody persistence.

Protective effect of Mangifera indica L. polyphenols on human T lymphocytes against activation-induced cell death.

Activation-induced cell death (AICD) plays an important role in maintenance of peripheral lymphocyte homeostasis. Reactive oxygen species (ROS) combined with simultaneous calcium (Ca(2+)) influx into the cytosol are required for induction of AICD. The extract obtained from the stem bark of Mangifera indica L. has shown to protect T cells from in vitro AICD. This extract is rich in polyphenolic compounds, the three main components of which are mangiferin (MA), catechin (C) and epicatechin (EC). The present study has focused on the possible contribution of the polyphenols MA, C and EC to the demonstrated protective effect of M. indica extract on in vitro human T cell AICD. Our results show that these polyphenols diminished the increase of intracellular ROS and free Ca(2+) induced by T cell receptor (TCR) triggering. In addition, these polyphenols attenuated AICD. Our findings suggest that the T cell survival effect of M. indica extract is mediated, at least in part, by its main polyphenols.