A phase I trial of CV706, a replication-competent, PSA selective oncolytic adenovirus, for the treatment of locally recurrent prostate cancer following radiation therapy.

CV706 is a prostate-specific antigen (PSA)-selective, replication-competent adenovirus that has been shown to selectively kill human prostate cancer xenografts in preclinical models. To study the safety and activity of intraprostatic delivery of CV706, a Phase I dose-ranging study for the treatment of patients with locally recurrent prostate cancer after radiation therapy was conducted. Twenty patients in five groups were treated with between 1 x 10(11) and 1 x 10(13) viral particles delivered by a real-time, transrectal ultrasound-guided transperineal technique using a three-dimensional plan. The primary end point was the determination of treatment-related toxicity. Secondary objectives included evaluation of the antitumor activity of CV706 and monitoring for other correlates of antineoplastic action. In this study, CV706 was found to be safe and was not associated with irreversible grade 3 or any grade 4 toxicity. No grade >1 alterations in liver function tests associated with CV706 administration were observed. Posttreatment prostatic biopsies and detection of a delayed "peak" of circulating copies of virus provided evidence of intraprostatic replication of CV706. The study defined the timing of CV706 shedding into blood and urine as well as the appearance of circulating Ad5 neutralizing antibodies. Finally, this study documents the serum PSA response of treated patients and reveals a dose response showing that all five patients who achieved a > or =50% reduction in PSA were treated with the highest two doses of CV706. This study represents the first clinical translation of a prostate-specific, replication-restricted adenovirus for the treatment of prostate cancer. Taken together, this study documents that intraprostatic delivery of CV706 can be safely administered to patients, even at high doses, and the data also suggest that CV706 possesses enough clinical activity, as reflected by changes in serum PSA, to warrant additional clinical and laboratory investigation.

Induction of immunity to prostate cancer antigens: results of a clinical trial of vaccination with irradiated autologous prostate tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor using ex vivo gene transfer.

Vaccination with irradiated granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting gene-transduced cancer vaccines induces tumoricidal immune responses. In a Phase I human gene therapy trial, eight immunocompetent prostate cancer (PCA) patients were treated with autologous, GM-CSF-secreting, irradiated tumor vaccines prepared from ex vivo retroviral transduction of surgically harvested cells. Expansion of primary cultures of autologous vaccine cells was successful to meet trial specifications in 8 of 11 cases (73%); the yields of the primary culture cell limited the number of courses of vaccination. Side effects were pruritus, erythema, and swelling at vaccination sites. Vaccine site biopsies manifested infiltrates of dendritic cells and macrophages among prostate tumor vaccine cells. Vaccination activated new T-cell and B-cell immune responses against PCA antigens. T-cell responses, evaluated by assessing delayed-type hypersensitivity (DTH) reactions against untransduced autologous tumor cells, were evident in two of eight patients before vaccination and in seven of eight patients after treatment. Reactive DTH site biopsies manifested infiltrates of effector cells consisting of CD45RO+ T-cells, and degranulating eosinophils consistent with activation of both Th1 and Th2 T-cell responses. A distinctive eosinophilic vasculitis was evident near autologous tumor cells at vaccine sites, and at DTH sites. B-cell responses were also induced. Sera from three of eight vaccinated men contained new antibodies recognizing polypeptides of 26, 31, and 150 kDa in protein extracts from prostate cells. The 150-kDa polypeptide was expressed by LNCaP and PC-3 PCA cells, as well as by normal prostate epithelial cells, but not by prostate stromal cells. No antibodies against prostate-specific antigen were detected. These data suggest that both T-cell and B-cell immune responses to human PCA can be generated by treatment with irradiated, GM-CSF gene-transduced PCA vaccines.

Ex-vivo gene therapy using cytokine-transduced tumor vaccines: molecular and clinical pharmacology.

Whether the current generation of cytokine gene-transduced tumor vaccines will show clinical efficacy is under study. Fortunately, the large safety profile so far observed with gene-transduced tumor vaccines can allow outpatient testing in large populations of patients in the adjuvant therapy situation. This will allow large studies statistically powered to see potentially important adjuvant therapy effects in the range that are observed for tamoxifen in breast cancer. For example, the outpatient, adjuvant therapy safety context has been established in the use of GM-CSF gene-transduced autologous prostate cancer vaccines following radical prostatectomy. Similar adjuvant therapy clinical trial efforts are anticipated with allogeneic breast, colon, pancreatic, and ovarian cancer in addition to prostate, renal cell carcinoma, and melanoma. The reverse translation of early clinical data back to basic laboratory research also suggests the field of cytokine gene-transduced tumor vaccine research will remain vibrant. Efforts are currently being directed on optimizing DC activation with polycistronic constructs of cytokine genes, and overexpressing the most relevant tumor-associated peptides. As in the case of antineoplastic drug development, not all lead compounds will become approved drugs in medical oncology. Rigorous yet innovative clinical trial designs will be key to the accelerated identification of cytokine gene-transduced vaccines that improve survival in cancer patients.

Cancer cells engineered to secrete granulocyte-macrophage colony-stimulating factor using ex vivo gene transfer as vaccines for the treatment of genitourinary malignancies.

When irradiated and administered intradermally as vaccines, cancer cells engineered to secrete high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) by gene transfer elicit potent anticancer immune responses in a variety of animal tumor models. Upon vaccination, antigens present in the cancer cells are phagocytosed and processed by skin dendritic cells. These dendritic cells then prime anticancer immune responses by presenting antigenic peptides to T cells. The immune responses generated are capable of eradicating small but lethal cancer cell inocula with minimal toxicity in preclinical animal tumor studies. To develop this vaccination strategy for the treatment of human genitourinary cancers, we have conducted phase I clinical trials using human genitourinary cancer cells as sources of cancer cell antigens. In the first human clinical trial of genetically engineered cancer cell vaccines, a phase I clinical trial of kidney cancer cell vaccines (n = 18), kidney cancer cells were removed at surgery, propagated briefly in vitro, and then genetically modified to secrete high levels of GM-CSF via ex vivo transduction with the retrovirus MFG-GM-CSF. After irradiation, the kidney cancer cells were administered as vaccines to 18 patients with advanced kidney cancers. Vaccine treatment, which caused few side effects, nonetheless appeared to trigger anticancer immune responses manifest as conversion of delayed-type hypersensitivity (DTH) skin responses against irradiated autologous cancer cells after vaccination. Biopsies of vaccine sites yielded findings reminiscent of biopsies from preclinical animal model studies, with evidence of vaccine cell recruitment of dendritic cells, T cells, and eosinophils. One patient with measurable kidney cancer metastases treated at the highest vaccine dose level experienced a partial treatment response. The bioactivity of GM-CSF-secreting autologous cancer cell vaccines was confirmed in a phase I clinical trial for prostate cancer (n = 8). Vaccine cells were prepared from surgically harvested prostate tumors by ex vivo transduction with MFG-GM-CSF in a manner similar to that used for the kidney cancer trial. Vaccine treatment was well tolerated and associated with induction of anticancer immunity as assessed using DTH skin testing. In addition, new antiprostate cancer cell antibodies were detected in serum samples from treated men as a consequence of vaccination. These first clinical trials of GM-CSF-secreting cancer cell vaccines for the treatment of genitourinary cancers have demonstrated both safety and bioactivity, in that very few side effects have been seen and anticancer immune responses have been detected. Future clinical studies will be required to assess vaccine treatment efficacy, refine vaccination dose and schedule, define the appropriate clinical context for the use of such vaccines, and ascertain optimal combinations involving vaccines and other local or systemic anticancer treatments.

Identification and characterization of the promoter for the human metastasis suppressor gene nm23-H1.

The nm23-H1 gene, localized to chromosome 17q21-22, has been demonstrated in transfection experiments to significantly inhibit the metastatic potential of melanoma and breast carcinoma cell lines. In this study, we report the isolation, sequencing and partial characterization of the nm23-H1 promoter. The nm23-H1 promoter has no TATA box, but it contains a number of sequences which may bind known transcriptional regulatory proteins (AP-1, CTF/NF1, ACAAAG, and Ets). We have also identified two nonconsensus transcriptional start sites within one of the Ets binding sites. Nuclear proteins from HeLa cells bound specifically to a 95 bp region of the nm23-H1 promoter which harbors the CTF/NF1 recognition consensus sequence, suggesting that CTF/NF1 may play a role in nm23-H1 expression.

Long term follow-up of women treated with 16-week, dose-intensive adjuvant chemotherapy for high risk breast carcinoma.

BACKGROUND: A Phase II study was performed evaluating the disease free and overall survival rates associated with a dose-intensive, 16-week, doxorubicin-based adjuvant chemotherapy regimen in women with breast carcinoma and > or = 10 involved axillary lymph nodes. METHODS: Eligible patients underwent staging with computed tomography and bone scanning and were treated with a 16-week, dose-intensive chemotherapy regimen, comprised of 8 2-week courses of cyclophosphamide, 100 mg/m2 orally, on Days 1-7; doxorubicin, 40 mg/m2 intravenously (i.v.), on Day 1; methotrexate, 100 mg/m2 i.v., on Day 1 with leucovorin rescue, 10 mg/m2, every 6 hours for 6 doses orally on Day 2; vincristine, 1 mg i.v. on Day 1; 5-fluorouracil (5-FU), 600 mg/m2 i.v., on Day 2 over 2 hours; and 5-FU, 300 mg/m2/day continuous i.v. on Days 8 and 9. Tamoxifen, 20 mg daily, was administered to patients with estrogen receptor positive tumors treated after October 1988. All patients were offered locoregional radiation therapy. RESULTS: Sixty-four women were treated on protocol. The median follow-up of 27 surviving patients was > 8 years at last follow-up. Three patients were lost to follow-up. The median time to progression was 54 months, the Kaplan-Meier estimate of event free survival at 5 years was 44% (95% confidence interval [CI], 31-56%), and the Kaplan-Meier estimate of overall survival at 5 years was 57% (95% CI, 44-69%). At 98 months the Kaplan-Meier estimate of freedom from recurrence was 31% (95% CI, 19-43%) and the Kaplan-Meier estimate of survival at 111 months was 36% (95% CI, 23-49%). CONCLUSIONS: Despite the use of dose-intensive, doxorubicin-based, adjuvant chemotherapy, and intensive staging prior to study entry, the results of the current study are similar to those of previous reports for standard dose chemotherapy and appear inferior to those reported for high dose therapy.