Marie-Claude Bonnet

Tumoral and Immunologic Response After Vaccination of Melanoma Patients With an ALVAC Virus Encoding MAGE Antigens Recognized by T Cells

PURPOSE To evaluate the toxicity, antitumoral effectiveness, and immunogenicity of repeated vaccinations with ALVAC miniMAGE-1/3, a recombinant canarypox virus containing a minigene encoding antigenic peptides MAGE-3(168-176) and MAGE-1(161-169), which are presented by HLA-A1 and B35 on tumor cells and can be recognized by cytolytic T lymphocytes (CTLs). MATERIALS AND METHODS The vaccination schedule comprised four sequential injections of the recombinant virus, followed by three booster vaccinations with the MAGE-3(168-176) and MAGE-1(161-169) peptides. The vaccines were administered, both intradermally and subcutaneously, at 3-week intervals. RESULTS Forty patients with advanced cancer were treated, including 37 melanoma patients. The vaccines were generally well tolerated with moderate adverse events, consisting mainly of transient inflammatory reactions at the virus injection sites. Among the 30 melanoma patients assessable for tumor response, a partial response was observed in one patient, and disease stabilization in two others. The remaining patients had progressive disease. Among the patients with stable or progressive disease, five showed evidence of tumor regression. A CTL response against the MAGE-3 vaccine antigen was detected in three of four patients with tumor regression, and in only one of 11 patients without regression. CONCLUSION Repeated vaccination with ALVAC miniMAGE-1/3 is associated with tumor regression and with a detectable CTL response in a minority of melanoma patients. There is a significant correlation between tumor regression and CTL response. The contribution of vaccine-induced CTL in the tumor regression process is discussed in view of the immunologic events that could be analyzed in detail in one patient.

Recombinant viruses as a tool for therapeutic vaccination against human cancers

Viral vectors can be used to express a variety of genes in vivo, that encode tumor associated antigens, cytokines, or accessory molecules. For vaccination purposes, the ideal viral vector should be safe and enable efficient presentation of expressed antigens to the immune system. It should also exhibit low intrinsic immunogenicity to allow for its re-administration in order to boost relevant specific immune responses. Furthermore, the vector system must meet criteria that enable its industrialization. The characteristics of the most promising viral vectors, including retroviruses, poxviruses, adenoviruses, adeno-associated viruses, herpes simplex viruses, and alphaviruses, will be reviewed in this communication. Such recombinant viruses have been successfully used in animal models as therapeutic cancer vaccines. Based on these encouraging results, a series of clinical studies, reviewed herein, have been undertaken. Human clinical trials, have as of today, allowed investigators to establish that recombinant viruses can be safely used in cancer patients, and that such recombinants can break immune tolerance against tumor-associated antigens. These promising results are now leading to improved immunization protocols associating recombinant viruses with alternate antigen-presentation platforms (prime-boost regimens), in order to elicit broad tumor-specific immune responses (humoral and cellular) against multiple target antigens.

Therapeutic vaccines against melanoma and colorectal cancer.

Our overall strategy is to develop multivalent recombinant vaccines capable of eliciting broad immune responses in patients with malignant melanoma or colorectal cancer. We report herein results from initial studies conducted in cancer patients to evaluate the effect of intratumoral administration of recombinant canarypox viruses carrying cytokine genes. Our current focus is on the induction of tumor-specific T-cell responses using a prime/boost immunization schedule with a unique vector system derived from the canary pox virus called ALVAC, in which we incorporate genes encoding Tumor Associated Antigens (TAAs) of interest. Clinical studies in colorectal cancer evaluating an ALVAC CEA candidate vaccine have shown that this approach is safe and can induce tumor-specific T cell responses. Additional clinical studies evaluating candidate vaccines against melanoma and colorectal cancer, targeting either the gp100, Mage 1, Mage 3 or p53 molecules are ongoing.

World wide experience with inactivated poliovirus vaccine.

As part of the global poliovirus eradication strategy, oral poliovirus vaccine (OPV) has successfully contributed to reduce polio incidence rates globally. However, because of the OPV-related risks of vaccine associated paralytic poliomyelitis (VAPP) and vaccine-derived polioviruses (VDPVs) OPV cessation is required in order to achieve complete eradication of polio. Inactivated poliovirus vaccine (IPV) is a viable option for incorporation into existing vaccination schedules so as to avoid these risks. Furthermore, the continuation of vaccination with IPV will protect populations in case of re-emergence of wild-type poliovirus from remote locations, laboratory samples, or through bioterrorism. The ability of IPV to prevent poliovirus outbreaks and provide herd protection has been demonstrated in several circumstances and in various settings. This paper reviews clinical experiences with IPV administration and outcomes in various countries in Europe, the Americas, Africa and Asia.

Randomized controlled study of fractional doses of inactivated poliovirus vaccine administered intradermally with a needle in the Philippines

OBJECTIVE Comparison of a fractional inactivated poliovirus vaccine (IPV) dose administered intradermally (ID) to a full dose administered intramuscularly (IM). METHODS Healthy Filipino infants were randomized to receive IPV as either a fractional (1/5(th)) dose ID by needle injection or a full dose IM at 6, 10, and 14 weeks and a booster at 15-18 months of age. Pre- and post-vaccination anti-polio 1, 2, and 3 titers were estimated. Adverse events were monitored throughout the study. RESULTS Following primary series vaccination, anti-polio 1, 2, and 3 titers were ≥8 (1/dil) in 99-100% of participants, and the ID route was non-inferior to the IM route. Depending on the study group, antibody persistence was detected in 83-100% of participants, and the booster dose resulted in a strong anamnestic response in all groups. The incidence of adverse events in each group was similar, except for injection-site erythema (higher in the ID group). CONCLUSIONS Primary series and booster vaccination of a fractional IPV dose administered by the ID route was highly immunogenic and well tolerated. These data confirm the medical validity of using fractional ID doses of IPV. The programmatic feasibility of implementing affordable mass vaccination programs based on this delivery mode has yet to be established.

Clinical phase I intratumoral administration of two recombinant ALVAC canarypox viruses expressing human granulocyte-macrophage colony-stimulating factor or interleukin-2: the transgene determines the composition of the inflammatory infiltrate.

Immunotherapy employs cytokines for modifying local inflammatory reactions. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to activate dendritic cells, macrophages, and granulocytes leading to clinical trials using GM-CSF-based cancer vaccine approaches. Interleukin-2 (IL-2) is an important T cell stimulatory cytokine approved as exogenous antitumor agent. The ALVAC viral vector system uses a recombinant canarypox virus for local gene expression. We report a phase I clinical trial using intratumoral administration of ALVAC GM-CSF or ALVAC IL-2 in skin metastases of melanoma or leiomyosarcoma. ALVAC GM-CSF and ALVAC IL-2 were injected at 107.12 and 106.92, 50% cell culture infectious dose in eight metastases with acceptable tolerability. Local and systemic inflammatory reactions were observed. The transgene determined the local infiltrate: GM-CSF induced monocyte and macrophage enrichment of the peritumoral inflammatory infiltrate, whereas IL-2 increased local T lymphocytes. Stable disease of injected lesions was seen after ALVAC GM-CSF application, whereas ALVAC IL-2 treatment led to partial regression in three out of eight injected tumors, accompanied by decreased expression of melanocytic antigens. Local GM-CSF expression could be induced. In summary, ALVAC GM-CSF and ALVAC IL-2 injections are safe and can mediate local biologic and immunologic effects.

Safety and immunogenicity of ALVAC wild-type human p53 (vCP207) by the intravenous route in rhesus macaques

p53 is over-expressed in approximately 50% of human cancers, and transfer of cytotoxic T lymphocytes (CTL) against wild-type p53 protects mice against p53-over-expressing tumors, suggesting that p53 might be an attractive target for immunotherapy. Immunization of mice with a recombinant canarypox virus, ALVAC, expressing human wild-type p53 (vCP207) prevented growth of p53-over-expressing tumors. Since intravenous administration induced better immune responses in mice than other routes, we have proposed to use this route in cancer patients. However, because this vector has never been administered intravenously to humans, and because of the possibility of inducing auto-immunity to a self-antigen, we felt it was necessary to first evaluate safety in rhesus macaques. We found that three intravenous administrations of vCP207 at proportional doses up to 10x those proposed for humans produced no abnormalities in hematologic or clinical chemistry parameters. Serologic markers of autoimmunity and inflammation were unaffected, despite the >95% amino acid identity between human and rhesus p53. Pathological examination of numerous tissues yielded findings comparable to those in animals given placebo. Some animals showed anti-p53 antibody responses following vaccination, indicating that tolerance could be broken to some extent. However, with the exception of one animal with a possible delayed type hypersensitivity reaction to p53 protein, we did not see evidence for a cell-mediated response. The safety profile in monkeys with ALVAC-p53 provides encouragement for using such live, modified vectors via the intravenous route for human immunotherapy.

Seroprevalence of anti-polio antibodies in a population 7 months to 39 years of age in Uruguay: implications for future polio vaccination strategies.

This study evaluated the seroprevalence of poliovirus types 1, 2 and 3 antibodies and vaccination coverage in 780 subjects aged between 7 months and 39 years in Montevideo, Uruguay, where oral polio vaccine (OPV) is used. Antibody titers were measured and seroprotection rates and geometric mean titers (GMTs) were compared among four age groups. Vaccination histories were recorded from documents and interviews. Seroprotection rates ranged from 72% to 95% in children aged 7-23 months, 31-77% in 2-9-year olds, 14-45% in 10-19-year olds and 20-59.5% in 20-39-year olds. Seroprotection decreased significantly with increasing age (p<0.05). Polio vaccination coverage was >90% for the two youngest age groups. These results could help guide public policy decisions regarding polio vaccination, and support the use of inactivated polio vaccine following cessation of OPV.

A Japanese study to assess immunogenicity and safety of a typhoid Vi polysaccharide vaccine

BACKGROUND Although typhoid fever is rare in Japan, imported cases have been reported occasionally in travelers returning from endemic areas. To achieve licensing of a typhoid Vi polysaccharide vaccine (Typhim Vi(®)) and make it widely available in Japan, this study was conducted at the request of the Japanese Ministry of Health Labor and Welfare to assess the immunogenicity and safety of this vaccine when given as a single dose (the recommended schedule of administration) in a Japanese population. METHODS In this multi-center, open-label, non-comparative, intervention study performed in Japan, 200 healthy volunteers (188 adults [≥ 18 years of age], 7 adolescents [12-17 years of age] and 5 children [2-11 years of age]) were administered Typhim Vi(®). Immunogenicity was assessed 28 days after vaccinations using an ELISA method of anti-Vi antibody detection. A 4-fold increase in anti-Vi titer was considered as the threshold for seroconversion for anti-Vi antibodies. Safety was assessed up to 28 days following vaccination. RESULTS Overall, 92.0% (95% confidence interval [CI]: 87.3-95.4%) of participants achieved seroconversion 28 days after a single dose of typhoid Vi polysaccharide vaccine. GMTs of Vi antibody titers increased from 6.6 (95% CI: 5.8-7.4) prior to vaccination to 157.3 (95% CI: 135.1-183.2) on Day 28 after vaccination. The geometric mean of individual anti-Vi antibody titer ratios (Day 28/Day 0) was 23.9 (95% CI: 20.3-28.3). There were no immediate adverse events and no adverse events led to the discontinuation of participants from the study. Across all age groups, pain and myalgia were the most frequently reported injection site and systemic reactions, respectively. Most of these reactions were mild in intensity and resolved within 7 days. CONCLUSIONS A single dose of typhoid Vi polysaccharide vaccine, Typhim Vi(®), demonstrated good safety and immunogenicity profile in a Japanese population.

Safety of a second dose of varicella vaccine administered at 4 to 6 years of age in healthy children in Argentina

Varicela Biken [Live varicella Biken vaccine (strain Oka)] is an effective and safe vaccine for the prevention of varicella infection. Although the recommended schedule in all age groups (children, adolescents and adults) is a single dose, physicians in some countries follow the 2007 recommendation of the US Advisory Committee on Immunization Practices (ACIP) which recommends “implementation of a routine 2-dose varicella vaccination program for children, with the first dose administered at age 12--15 months and the second dose at age 4--6 years.”1 Therefore, cases can arise when two doses of Varicela Biken are given even though the ACIP guidelines are a response to the US epidemiological situation and for US licensed products based on the Oka/Merck and the Oka-RIT strains (Varicela Biken is not registered in US). The aim of this study is to ascertain the safety of a second dose of Varicela Biken in children who have been previously vaccinated with the same vaccine. In this study, children, 4-6 years of age who had been previously vaccinated with Varicela Biken, received a single 0.5mL dose of live attenuated varicella virus vaccine containing at least 1000 Plaque Forming Units (PFU) attenuated live Varicella-zoster virus (Oka strain). Participants were monitored for 30 minutes after vaccination. Predefined injection site and systemic reactions were solicited during the subsequent seven days. Unsolicited injection site reactions and unsolicited systemic events were collected throughout the study. Any serious adverse events occurring throughout the study were reported to the sponsor’s pharmacovigilance department. One hundred and twenty two children were recruited and all provided safety data. There were no immediate adverse events or injection site reactions. Forty three percent of participants reported injection site reactions and 22.1% reported systemic reactions on solicitation during the seven days after vaccination. During the 30 day monitoring period, 43 participants reported a total of 66 adverse events. Seven participants reported a total of eight unsolicited events that were assessed as related to the vaccine or where the relationship to vaccination was unknown. Five of these eight events were injection site reactions and all were mild, systemic reactions included mild rash (1 case) and fever (2 cases). There was a single serious adverse event that was not related to the study medication (subject was a passenger in a motor vehicle accident). A second dose of Varicela Biken was well tolerated and showed no significant safety issues in this population of previously vaccinated children.