Clinical protocol. A phase II study: efficacy of the gene therapy of the MVA E2 recombinant virus in the treatment of precancerous lesions (NIC I and NIC II) associated with infection of oncogenic human papillomavirus

Strategies to obtain multiple recombinant modified vaccinia Ankara vectors. Applications to influenza vaccines

As a vaccination vector, MVA has been widely investigated both in animal models and humans. The construction of recombinant MVA (rMVA) relies on homologous recombination between an acceptor virus and a donor plasmid in infected/transfected permissive cells. Our construction strategy "Red-to-Green gene swapping" - based on the exchange of two fluorescent markers within the flanking regions of MVA deletion ΔIII, coupled to fluorescence activated cell sorting - is here extended to a second insertion site, within the flanking regions of MVA deletion ΔVI. Exploiting this strategy, both double and triple rMVA were constructed, expressing as transgenes the influenza A proteins HA, NP, M1, and PB1. Upon validation of the harbored transgenes co-expression, double and triple recombinants rMVA(ΔIII)-NP-P2A-M1 and rMVA(ΔIII)-NP-P2A-M1-(ΔVI)-PB1 were assayed for in vivo immunogenicity and protection against lethal challenge. In vivo responses were identical to those obtained with the reported combinations of single recombinants, supporting the feasibility and reliability of the present improvement and the extension of Red-to-Green gene swapping to insertion sites other than ΔIII.

Local HPV Recombinant Vaccinia Boost Following Priming with an HPV DNA Vaccine Enhances Local HPV-Specific CD8+ T-cell-Mediated Tumor Control in the Genital Tract

PURPOSE

Two viral oncoproteins, E6 and E7, are expressed in all human papillomavirus (HPV)-infected cells, from initial infection in the genital tract to metastatic cervical cancer. Intramuscular vaccination of women with high-grade cervical intraepithelial neoplasia (CIN2/3) twice with a naked DNA vaccine, pNGVL4a-sig/E7(detox)/HSP70, and a single boost with HPVE6/E7 recombinant vaccinia vaccine (TA-HPV) elicited systemic HPV-specific CD8 T-cell responses that could traffic to the lesion and was associated with regression in some patients (NCT00788164).

EXPERIMENTAL DESIGN

Here, we examine whether alteration of this vaccination regimen by administration of TA-HPV vaccination in the cervicovaginal tract, rather than intramuscular (IM) delivery, can more effectively recruit antigen-specific T cells in an orthotopic syngeneic mouse model of HPV16(+) cervical cancer (TC-1 luc).

RESULTS

We found that pNGVL4a-sig/E7(detox)/HSP70 vaccination followed by cervicovaginal vaccination with TA-HPV increased accumulation of total and E7-specific CD8(+) T cells in the cervicovaginal tract and better controlled E7-expressing cervicovaginal TC-1 luc tumor than IM administration of TA-HPV. Furthermore, the E7-specific CD8(+) T cells in the cervicovaginal tract generated through the cervicovaginal route of vaccination expressed the α4β7 integrin and CCR9, which are necessary for the homing of the E7-specific CD8(+) T cells to the cervicovaginal tract. Finally, we show that cervicovaginal vaccination with TA-HPV can induce potent local HPV-16 E7 antigen-specific CD8(+) T-cell immune responses regardless of whether an HPV DNA vaccine priming vaccination was administered IM or within the cervicovaginal tract.

CONCLUSIONS

Our results support future clinical translation using cervicovaginal TA-HPV vaccination.

Regression of human papillomavirus intraepithelial lesions is induced by MVA E2 therapeutic vaccine

Human papilloma viruses can induce warts, condylomas, and other intraepithelial cervical lesions that can progress to cancer. Cervical cancer is a serious problem in developing countries because early detection is difficult, and thus proper early treatment is many times missing. In this phase III clinical trial, we evaluated the potential use of MVA E2 recombinant vaccinia virus to treat intraepithelial lesions associated with papillomavirus infection. A total of 1176 female and 180 male patients with intraepithelial lesions were studied. They were injected with 10(7) MVA E2 virus particles directly into their uterus, urethra, vulva, or anus. Patients were monitored by colposcopy and cytology. Immune response was determined by measuring the antibody titer against MVA E2 virus and by analyzing the cytotoxic activity against cancer cells bearing papillomavirus DNA. Papillomavirus was determined by the Hybrid Capture method or by polymerase chain reaction analysis. By histology, 1051 (89.3%) female patients showed complete elimination of lesions after treatment with MVA E2. In 28 (2.4%) female patients, the lesion was reduced to CIN 1. Another 97 (8.3%) female patients presented isolated koilocytes after treatment. In men, all lesions were completely eliminated. All MVA E2-treated patients developed antibodies against the MVA E2 vaccine and generated a specific cytotoxic response against papilloma-transformed cells. Papillomavirus DNA was not detected after treatment in 83% of total patients treated. MVA E2 did not generate any apparent side effects. These data suggest that therapeutic vaccination with MVA E2 vaccine is an excellent candidate to stimulate the immune system and generate regression in intraepithelial lesions when applied locally.

[Prophylactic and therapeutic vaccines against human papilloma virus]

Infection with human papilloma virus (HPV) has been identified as the cause of recurrent papillomatosis and of a subgroup of squamous cell carcinomas of the head and neck. A change in prevalence of these lesions, especially for oropharyngeal carcinoma, can be expected as a consequence of the introduction of prophylactic HPV vaccines for young women, targeting the most frequent high- and low-risk HPV subtypes. Vaccination for the major low-risk HPV types has proven to be highly effective against genital warts and activity against papillomatosis can be expected. The possibilities of prophylactic HPV vaccination as well as new developments and the rationale for therapeutic vaccines are discussed on the basis of the current literature.

In vitro host range, multiplication and virion forms of recombinant viruses obtained from co-infection in vitro with a vaccinia-vectored influenza vaccine and a naturally occurring cowpox virus isolate

Background

Poxvirus-vectored vaccines against infectious diseases and cancer are currently under development. We hypothesized that the extensive use of poxvirus-vectored vaccine in future might result in co-infection and recombination between the vaccine virus and naturally occurring poxviruses, resulting in hybrid viruses with unpredictable characteristics. Previously, we confirmed that co-infecting in vitro a Modified vaccinia virus Ankara (MVA) strain engineered to express influenza virus haemagglutinin (HA) and nucleoprotein (NP) genes with a naturally occurring cowpox virus (CPXV-NOH1) resulted in recombinant progeny viruses (H Hansen, MI Okeke, Ø Nilssen, T Traavik, Vaccine 23: 499–506, 2004). In this study we analyzed the biological properties of parental and progeny hybrid viruses.

Results

Five CPXV/MVA progeny viruses were isolated based on plaque phenotype and the expression of influenza virus HA protein. Progeny hybrid viruses displayed in vitro cell line tropism of CPXV-NOH1, but not that of MVA. The HA transgene or its expression was lost on serial passage of transgenic viruses and the speed at which HA expression was lost varied with cell lines. The HA transgene in the progeny viruses or its expression was stable in African Green Monkey derived Vero cells but became unstable in rat derived IEC-6 cells. Hybrid viruses lacking the HA transgene have higher levels of virus multiplication in mammalian cell lines and produced more enveloped virions than the transgene positive progenitor virus strain. Analysis of the subcellular localization of the transgenic HA protein showed that neither virus strain nor cell line have effect on the subcellular targets of the HA protein. The influenza virus HA protein was targeted to enveloped virions, plasma membrane, Golgi apparatus and cytoplasmic vesicles.

Conclusion

Our results suggest that homologous recombination between poxvirus-vectored vaccine and naturally circulating poxviruses, genetic instability of the transgene, accumulation of non-transgene expressing vectors or hybrid virus progenies, as well as cell line/type specific selection against the transgene are potential complications that may result if poxvirus vectored vaccines are extensively used in animals and man.

Medical treatment of cervical intraepithelial neoplasia II, III: an update review

Cervical intraepithelial neoplasia (CIN) II, III is a preinvasive stage of squamous cell carcinoma of the uterine cervix. The standard treatment for CIN II, III consists of ablation and excision. However, nonsurgical treatment may be necessary for some women to preserve future reproductive potential. This review was conducted to summarize available published data on the efficacy and safety of medical treatment for CIN II, III. Based on existing studies, cyclooxygenase (COX)-2 inhibitors; indole-3-carbinol; and novel immunotherapy agents, including ZYC101a, MVA E2, and HspE7, have been observed as possessing therapeutic activity without any major treatment-related complications. These promising results provide important data for the future direction of clinical research.

Vaccination with recombinant modified vaccinia virus Ankara expressing bovine respiratory syncytial virus (bRSV) proteins protects calves against RSV challenge

Respiratory syncytial virus (RSV) is a major cause of severe respiratory disease in infants and calves. Bovine RSV (bRSV) is a natural pathogen for cattle, and bRSV infection in calves shares many features with the human infection. Thus, bRSV infection in cattle provides the ideal setting to evaluate the safety and efficacy of novel RSV vaccine strategies. Here, we have evaluated the efficacy and safety of modified vaccinia virus Ankara (rMVA)-based vaccine candidates, expressing the bovine RSV-F protein, either or not in combination with the G protein, in colostrums-deprived SPF calves born by caesarean section. Vaccination induced bRSV-specific IgG and CD8 T cell responses. Importantly, no IgE responses were detected. After bRSV challenge, rMVA vaccinated calves experienced less severe symptoms of lower respiratory tract disease compared to the mock-immunized control group. Immunized animals showed reduced pulmonary virus loads, and no eosinophilic infiltration or enhanced respiratory distress. In conclusion, candidate rMVA/bRSV vaccines induced protective and safe immune responses in calves.

MVA E2 recombinant vaccine in the treatment of human papillomavirus infection in men presenting intraurethral flat condyloma: a phase I/II study

BACKGROUND

Human papillomavirus (HPV) is the etiologic agent for warts and cervical cancer. In Mexico, the death rate from cervical cancer is extremely high, and statistical data show that since 1990 the number of deaths is increasing. Condylomas and cancer of the penis are the most common lesions presented in men; bladder and prostate cancer in men are also associated with the presence of HPV. Since HPV is transmitted by sexual intercourse, treating both partners is necessary in order to eliminate the virus in the population. Approaches to this include preventative vaccines such as Gardasil, and therapeutic vaccines to treat established infections in both men and women. This will be the only way to decrease the numbers of deaths due to this malignancy.

PATIENTS AND METHODS

We conducted a phase I/II clinical trial to evaluate the potential use of the recombinant vaccinia viral vaccine MVA E2 (composed of modified vaccinia virus Ankara [MVA] expressing the E2 gene of bovine papillomavirus) to treat flat condyloma lesions associated with oncogenic HPV in men. Fifty male patients with flat condyloma lesions were treated with either MVA E2 therapeutic vaccine or fluorouracil (5-fluorouracil). Thirty men received the therapeutic vaccine, at a total of 10(6) virus particles per dose, administered directly into the urethra once every week over a 4-week period. Twenty control patients were treated with 5% fluorouracil 1mL twice weekly over a 4-week period directly into the urethra. Reduction of lesions or absence of papillomavirus infection was monitored by colposcopy and histologic analysis. The immune response after MVA E2 treatment was determined by measuring the antibodies against the MVA E2 virus and by analyzing the lymphocyte cytotoxic activity against cancer cells bearing oncogenic papillomavirus. Presence of papillomavirus was determined by the Hybrid Capture method.

RESULTS

Twenty-eight of 30 patients showed no lesion or presence of papillomavirus as diagnosed by colposcopy and brush histologic examination after 4 weeks of MVA E2 treatment. These patients showed complete elimination of flat condyloma in the urethra and no acetowhite spots were detected over the prepuce. In two other patients the acetowhite spots and flat condyloma did not diminish. All patients developed antibodies against the MVA E2 vaccine and E2 protein, and generated a specific cytotoxic response against papilloma-transformed cells. Viral DNA was not detected in MVA E2-treated patients. In the control group, 13 of 20 patients were free of lesions. Three of these patients had recurrence of lesions after 3 months of treatment and none of the patients developed specific antibodies against cancer cells. In contrast, patients treated with MVA E2 did not show any recurrence of lesions after 1 year of treatment. In addition, none of the patients had local or systemic adverse effects according to the WHO classification 1-4.

CONCLUSIONS

Therapeutic vaccination with MVA E2 proved to be very effective in stimulating the immune system against papillomavirus, and in generating regression of flat condyloma lesions in men.

Regression of papilloma high-grade lesions (CIN 2 and CIN 3) is stimulated by therapeutic vaccination with MVA E2 recombinant vaccine

Human papillomavirus (HPV) is the etiologic agent for cervical cancer. In Mexico, a women dies every 2 h, and since 1990 the statistics have shown that the numbers of deaths are increasing. We conducted a phase II clinical trial to evaluate the potential use of the MVA E2 recombinant vaccinia virus in treating high-grade lesions (CIN 2 and CIN 3) associated with oncogenic papillomavirus. Fifty-four female patients with high degree lesions were treated either with an MVA E2 therapeutic vaccine or with conization. Thirty-four women received the therapeutic vaccine, at a total of 10(7) virus particles per dose injected directly into the uterus once every week over a 6-week period. Twenty control patients were treated with conization. By colposcopy, 19 patients out of 34 showed no lesion, in three patients the lesions were reduced by 85-90%, in eight other lesions had reduced by 60%, and in four more patients, they were reduced by 25%. Histological analysis showed total elimination of high-grade lesions in 20 out of 34 patients after treatment with MVA E2. Eleven patients had a 50% reduction in lesion size. In two other patients, the lesion was reduced to CIN 2 and in one more patient the lesion was reduced to low grade (CIN 1). All patients developed antibodies against the MVA E2 vaccine, and generated a specific cytotoxic response against papilloma-transformed cells. DNA viral load was significantly reduced in MVA E2-treated patients. Conization eliminated the lesions in 80% of the patients, but patients did not develop cytotoxic activity specific against cancer cells and did not eliminate the papillomavirus. In addition, three patients treated with conization had recurrence of lesions 1 year later. These results show that therapeutic vaccination with MVA E2 proved to be very effective in stimulating the immune system against papillomavirus, and in generating regression of high-grade lesion.

Modified vaccinia virus Ankara multiplies in rat IEC-6 cells and limited production of mature virions occurs in other mammalian cell lines

Recombinant viruses based on modified vaccinia virus Ankara (MVA) are vaccine candidates against infectious diseases and cancers. Presently, multiplication of MVA has been demonstrated in chicken embryo fibroblast and baby hamster kidney (BHK-21) cells only. The multiplication and morphogenesis of a recombinant (MVA-HANP) and non-recombinant MVA strain in BHK-21 and 12 other mammalian cell lines have now been compared. Rat IEC-6 cells were fully permissive to MVA infection. The virus yield in IEC-6 cells was similar to that obtained in BHK-21 cells at low as well as high multiplicities of infection. Vero cells were semi-permissive to MVA infection. Mature virions were produced in supposedly non-permissive cell lines. The multiplication and morphogenesis of non-recombinant MVA and MVA-HANP were similar. These results are relevant to the production and biosafety of MVA-vectored vaccines.

Modified vaccinia virus Ankara as antigen delivery system: how can we best use its potential?

Safety-tested modified vaccinia virus Ankara (MVA) has been established as a potent vector system for the development of candidate recombinant vaccines. The versatility of the vector system was recently demonstrated by the rapid production of experimental MVA vaccines for immunization against severe acute respiratory syndrome associated coronavirus. Promising results were also obtained in the delivery of Epstein-Barr virus or human cytomegalovirus antigens and from the clinical testing of MVA vectors for vaccination against immunodeficiency virus, papilloma virus, Plasmodium falciparum or melanoma. Moreover, MVA is considered to be a prime candidate vaccine for safer protection against orthopoxvirus infections. Thus, vector development to challenge dilemmas in vaccinology or immunization against poxvirus biothreat seems possible, yet the right choice should be made for a most beneficial use.

Fighting Cancer with Vaccinia Virus: Teaching New Tricks to an Old Dog

Vaccinia virus has played a huge part in human beings' victory over smallpox. With smallpox being eradicated and large-scale vaccination stopped worldwide, vaccinia has assumed a new role in our fight against another serious threat to human health: cancer. Recent advances in molecular biology, virology, immunology, and cancer genetics have led to the design of novel cancer therapeutics based on vaccinia virus backbones. With the ability to infect efficiently a wide range of host cells, a genome that can accommodate large DNA inserts and express multiple genes, high immunogenicity, and cytoplasmic replication without the possibility of chromosomal integration, vaccinia virus has become the platform of many exploratory approaches to treat cancer. Vaccinia virus has been used as (1) a delivery vehicle for anti-cancer transgenes, (2) a vaccine carrier for tumor-associated antigens and immunoregulatory molecules in cancer immunotherapy, and (3) an oncolytic agent that selectively replicates in and lyses cancer cells.

Therapeutic vaccination with MVA E2 can eliminate precancerous lesions (CIN 1, CIN 2, and CIN 3) associated with infection by oncogenic human papillomavirus

Human papillomavirus (HPV) infection is associated with cervical cancer. Papillomaviruses can induce diseases ranging from warts and condylomata to lesions that can progress to malignant neoplasias. Cervical cancer is a serious problem in developing countries because it is usually not detected at an early stage. In Mexico, a woman dies every 2 hr from this malignancy. In a phase I/II clinical trial, we evaluated the potential use of the MVA E2 recombinant vaccinia virus to treat cervical intraepithelial neoplasia CIN 1, CIN 2, and CIN 3 lesions associated with human papillomavirus (HPV) infection. Seventy-eight women with CIN 1-, CIN 2-, and CIN 3-grade lesions were treated with either an MVA E2 recombinant virus vaccine or with cryosurgery. Thirty-six women received the recombinant virus vaccine at a total of 10(7) MVA E2 virus particles injected directly into the uterus once every week over a 6-week period. Forty-two patients were treated with cryosurgery. Reduction of lesions was monitored weekly by colposcopy and cytologic analysis. The type of immune response after MVA E2 injection was determined by measuring antibody titers against MVA E2 virus and the E2 protein, and by the presence of cytotoxic activity against cancer cells bearing papillomavirus DNA. The presence of papillomavirus was determined by with the hybrid capture method. Thirty-four of 36 patients showed complete elimination of precancerous lesions after treatment with the MVA E2 vaccine. In two patients, precancerous lesions were reduced from grade CIN 3 to CIN 1. Three other patients presented isolated koilocytes after treatment with MVA E2. Colposcopy revealed no lesions in 85% of patients, and only small aceto-white spots were detected in 15% of patients after treatment with MVA E2. All patients developed antibodies against the MVA E2 vaccine, and vaccination generated a specific cytotoxic response against HPV-transformed cells. Furthermore, 50% of patients showed no evidence of papillomavirus after treatment with MVA E2, while the remaining 50% showed persistence of HPV DNA, but at approximately only 10% of the original viral load. The presence of cells cytotoxic to HPV-transformed cells, and the generation of antibodies against MVA E2, correlated with the elimination of lesions and with a remarkable reduction of HPV viral load in all patients treated with MVA E2. Additionally, the MVA E2 vaccine did not produce any apparent side effects in any of the patients treated. Cryosurgery eliminated the lesions of CIN 1 in all patients, but patients so treated did not develop cytotoxic activity against cancer cells. These results show that therapeutic vaccination with MVA E2 vaccine is an excellent prospective means for stimulating the immune system and causing the regression of precancerous CIN 1, CIN 2, and CIN 3 lesions when the vaccine is given locally.