Pilot study of vaccination with recombinant CEA-MUC-1-TRICOM poxviral-based vaccines in patients with metastatic carcinoma. Poxviral vectors have a proven safety record and can be used to incorporate multiple transgenes. Prior clinical trials with poxviral vaccines have shown that immunologic tolerance to self-antigens can be broken. Carcinoembryonic antigen (CEA) and breast cancer-associated epithelial mucin (MUC-1) are overexpressed in a substantial proportion of common solid carcinomas. The primary end point of this study was vaccine safety, with immunologic and clinical responses as secondary end points. We report here a pilot study of 25 patients treated with a poxviral vaccine regimen consisting of the genes for CEA and MUC-1, along with a triad of costimulatory molecules (TRICOM; composed of B7.1, ICAM-1, and LFA-3) engineered into vaccinia (PANVAC-V) as a prime vaccination and into fowlpox (PANVAC-F) as a booster vaccination. The vaccine was well tolerated. Apart from injection-site reaction, no grade ≥2 toxicity was seen in more than 2% of the cycles. Immune responses to MUC-1 and/or CEA were seen following vaccination in 9 of 16 patients tested. A patient with clear cell ovarian cancer and symptomatic ascites had a durable (18-month) clinical response radiographically and biochemically, and one breast cancer patient had a confirmed decrease of more than 20% in the size of large liver metastasis. This vaccine strategy seems to be safe, is associated with both CD8 and CD4 immune responses, and has shown evidence of clinical activity. Further trials with this agent, either alone or in combination with immunopotentiating and other therapeutic agents, are warranted. Safety and immunologic response of a viral vaccine to prostate-specific antigen in combination with radiation therapy when metronomic-dose Interleukin 2 is used as an adjuvant. We have previously reported on the safety and immunologic response of a poxvirus-based vaccine encoding prostate-specific antigen (PSA) used in combination with radiation therapy in patients with localized prostate cancer. We hypothesized that a metronomic dose of interleukin 2 (IL-2) as a biological adjuvant would cause less toxicity while maintaining immunologic response. Eighteen patients with localized prostate cancer were treated in a single arm trial using previously established doses of vaccine and radiation therapy. The vaccine used was a recombinant vaccinia virus engineered to encode PSA admixed with a recombinant vaccinia encoding the costimulatory molecule B7.1, followed by booster vaccinations with a recombinant fowlpox vector expressing prostate-specific antigen (PSA). Definitive external beam radiation therapy was initiated after the third vaccination cycle. Patients were evaluated for safety and immunologic response. Toxicity and immunologic activity were compared with the previously reported regimen containing a higher dose of IL-2. Seventeen of 18 patients received all eight cycles of vaccine with IL-2. Five of eight HLA-A2+ patients evaluated had an increase in PSA-specific T cells of ≥3-fold. Toxicities were generally mild, with only seven vaccination cycles of 140 given resulting in grade 3 toxicities possibly attributable to IL-2. Metronomic-dose IL-2 in combination with vaccine and radiation therapy is safe, can induce prostate-specific immune responses, and has immunologic activity similar to low-dose IL-2, with markedly reduced toxicities. Clinical safety of a viral vector based prostate cancer vaccine strategy. The primary objective of this phase I study was to evaluate the clinical safety of a vaccine using recombinant vaccinia virus (prime) and recombinant fowlpox virus (boost) in combination with granulocyte-macrophage colony-stimulating factor in patients with prostate cancer. The vaccines contained transgenes for prostate specific antigen, a triad of co-stimulatory molecules and a tumor antigen whose amino acid sequence had been modified to enhance its immunogenicity. Secondary end points were immunological and clinical responses, changes in prostate specific antigen velocity, and the kinetics of vaccinia virus clearance from the vaccination site, serum, peripheral blood mononuclear cells, urine and saliva. Based on the safety and preliminary immunogenicity results of this trial we recommend initiating a randomized, phase II study of prostate specific antigen/triad of co-stimulatory molecules vaccines in patients with less advanced prostate cancer. Analysis of overall survival in patients with nonmetastatic castration-resistant prostate cancer treated with vaccine, nilutamide, and combination therapy. We reported previously the first randomized study of any kind in patients with nonmetastatic, castrate-resistant prostate cancer. The study employed vaccine, the hormone nilutamide, and the combined therapy (crossover for each arm) with an endpoint of time to progression. We now report survival analyses at 6.5 years from the initiation of therapy with a median potential follow-up of 4.4 years. Forty-two patients were randomized to receive either a poxvirus-based prostate-specific antigen (PSA) vaccine or nilutamide. Patients in either arm who developed increasing PSA without radiographic evidence of metastasis could cross over to receive the combined therapies. Median survival among all patients was 4.4 years from date of enrollment. Median survival exhibited a trend toward improvement for patients initially randomized to the vaccine arm (median, 5.1versus 3.4 years; P = 0.13). Starting from the on-study date, the retrospectively determined subset of 12 patients who initially received vaccine and then later received nilutamide suggested improved survival compared with the 8 patients who began with nilutamide and subsequently were treated with vaccine (median, 6.2 versus 3.7 years; P = 0.045). A subgroup analysis of patients randomized to the vaccine arm versus the nilutamide arm showed substantial improvements in survival if at baseline patients had a Gleason score less than 7 (P = 0.033) and PSA less than 20 ng/dL (P = 0.013) or who had prior radiation therapy (P = 0.018). These data indicate that patients with nonmetastatic castration-resistant prostate cancer (D0.5) who receive vaccine before second-line hormone therapy may potentially result in improved survival compared with patients who received hormone therapy and then vaccine. These data also suggest that patients with more indolent disease may derive greater clinical benefit from vaccine alone or vaccine before second-line hormone therapy compared with hormone therapy alone or hormone therapy followed by vaccine. These findings have potential implications for both the design and endpoint analysis of larger vaccine combination therapy trials.
Showing the most recent 10 out of 18 publications
