Allogeneic Tumor Cell Vaccine Research Articles

Allogeneic "Zombie Cell" as Off-The-Shelf Vaccine for Postsurgical Cancer Immunotherapy.

Allogeneic tumor cell vaccines provide off-the-shelf convenience but lack patient specificity due to heterogeneity in tumor antigens. Here, allogeneic tumor cell corpses are converted into "zombie cells" capable of assimilating heterogeneous tumor by seizing cancer cells and spreading adjuvant infection. This causes pseudo-oncolysis of tumors, transforming them into immunogenic targets for enhanced phagocytosis. It is shown that in postoperative tumor models, localized delivery of premade "zombie cells" through stepwise gelation in resection cavity consolidates tumor surgery. Compared to analogous vaccines lacking "seizing" or "assimilating" capability, "zombie cell" platform effectively mobilizes T cell response against residual tumors, and establishes immunological memory against tumor re-challenge, showing less susceptibility to immune evasion. Despite using allogeneic sources, "zombie cell" platform functions as generalizable framework to produce long-term antitumor immunity in different tumor models, showing comparable effect to autologous vaccine. Together, with the potential of off-the-shelf availability and personalized relevance to heterogenous tumor antigens, this study suggests an alternative strategy for timely therapy after tumor surgery.

Neoadjuvant and adjuvant antitumor vaccination alone or combination with PD1 blockade and CD137 agonism in patients with resectable pancreatic adenocarcinoma.

558 Background: Utilizing a vaccine that induces and activates host effector T cells and co-administering it with immune modulating agents that enhance anti-tumor T cell activity is a potential strategy for overcoming pancreatic adenocarcinoma’s (PDA) resistance to immunotherapy. Our prior clinical trial demonstrated a GM-CSF-secreting, allogeneic tumor cell vaccine (GVAX) increases infiltrating CD8+ T cells in PDA. Follow up preclinical work demonstrated therapeutic synergy between GVAX and PD-1inhibition (PD1) with efficacy further enhanced by CD137 agonism (CD137). Methods: This was a 3-arm trial of neoadjuvant & adjuvant GVAX-based therapy in resectable (r) PDA patients (pts). Adults with clinically resectable, untreated PDA were enrolled in 1 of 3 study treatments: Arm A (GVAX alone), Arm B (GVAX + PD1 [Nivolumab]), or arm C (GVAX + PD1 + CD137 [Urelumab]). Treatment was given as follows: Day 1 - Cyclophosphamide 200mg/m2 IV (All Arms), Nivolumab 480mg IV (Arms B, C), Urelumab 8mg IV (Arm C); Day 2 – GVAX ID (All Arms). Pts were treated at 3 timepoints: 1) once 2 weeks prior to surgery; 2) once post-surgical recovery prior to standard of care adjuvant chemotherapy (SOC); 3) every month (up to 4 mo) following completion of SOC (if disease-free). SOC regimes included (m)FOLFIRINOX, Gem +/- Cap/NAB-Paclitaxel. The study was powered for a primary biologic endpoint: treatment-related change in intratumoral CD8+CD137+ T cells. Clinical endpoints included disease-free survival (DFS: time from surgery to recurrence), overall survival (OS: time from surgery to death), and safety. Results: 38 pts (N = 15 [Arm A], N = 13 [Arm B], N = 10 [Arm C]) were eligible for efficacy analysis (had R0/R1 resection) and 45 pts (N = 17 [A], N = 17 [B], N = 11 [C]) were eligible for safety analysis (had ≥1 dose of study treatment). Demographics, surgical pathology features, and SOC durations were similar in all Arms. At median follow up of 23 mo [A], 26 mo [B], and 22 mo [C], median DFS (95% CI) was 14.82 mo (6.0, NA), 16.23 mo (7.49, NA) and not reached (16.33, NA) for Arms A, B, C, respectively. There was no DFS benefit to adding PD1 compared to GVAX alone (HR 0.98 [95% CI 0.42, 2.27], p = 0.96). Combination CD137 + PD1 + GVAX was associated with marginally significant improved DFS compared to GVAX alone (HR 0.38 [95%CI 0.12, 1.19], p = 0.097) and GVAX + PD1 (HR 0.38 [95%CI 0.12, 1.21], p = 0.103). Median OS (95% CI) was 25.0 mo (18.8, NA), 26.4 mo (20.3, NA), and not yet reached for Arms A, B, C, respectively. There were no serious adverse events. In Arm C, 1 pt had grade 3 rash that delayed treatment and there was 1 instance of grade 2 AST/ALT elevation. The biologic endpoint will be reported at the meeting. Conclusions: Despite a small sample size, combining GVAX with dual immune-targeting of PD-1 blockade and CD137 agonism was safe and may enhance DFS in rPDA pts treated in the perioperative and post-adjuvant settings. Clinical trial information: NCT02451982.

MS 08.04 Immunotherapy in MPM

MS 08.04 Immunotherapy in MPM

SC05.04 Lung Cancer Vaccines: An Update

SC05.04 Lung Cancer Vaccines: An Update

MTE13.02 Basic Immunology for the Clinician

MTE13.02 Basic Immunology for the Clinician

Preliminary Results of a Pilot Study Evaluating An Allogeneic GM-CSF Pancreatic Tumor Cell Vaccine (GVAX) and Cytoxan (Cy) With Stereotactic Body Radiation Therapy (SBRT) and Folfirinox (FFX) in Patients With Resected Pancreatic Adenocarcinoma

Favorable Perioperative and Survival Outcomes After Resection of Borderline Resectable Pancreatic Cancer Treated With Neoadjuvant Stereotactic Radiation and Chemotherapy Compared With Upfront Pancreatectomy for Resectable Cancer E.A. Mellon, T. Strom, S.E. Hoffe, J.M. Frakes, G.M. Springett, P.J. Hodul, M.P. Malafa, M.D. Chuong, and R. Shridhar; H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, University of Maryland School of Medicine, Baltimore, MD

A phase III study of belagenpumatucel-L, an allogeneic tumour cell vaccine, as maintenance therapy for non-small cell lung cancer

BackgroundTreatment options after first-line chemotherapy are limited in non-small cell lung cancer (NSCLC). Belagenpumatucel-L is a therapeutic vaccine comprised of 4 transforming growth factor (TGF)-β2-antisense gene-modified, irradiated, allogeneic NSCLC cell lines that may be useful for maintenance after initial treatment. MethodsStage III/IV NSCLC patients who did not progress after platinum-based chemotherapy were randomised 1:1 to receive maintenance belagenpumatucel-L or placebo. Patients were eligible for randomisation between one and four months from the end of induction chemotherapy. The primary endpoint was overall survival. ResultsThis phase III trial enrolled 270 patients in the belagenpumatucel-L arm and 262 in the control arm. Belagenpumatucel-L was well tolerated with no serious safety concerns. There was no difference in survival between the arms (median survival 20.3 versus 17.8months with belagenpumatucel-L versus placebo, respectively; hazard ratio (HR) 0.94, p=0.594). There were also no differences in progression-free survival (4.3months versus 4.0 for belagenpumatucel-L vs placebo, respectively; HR 0.99, p=0.947). A prespecified Cox regression analysis demonstrated that the time elapsed between randomisation and the end of induction chemotherapy had a significant impact on survival (p=0.002) and that prior radiation was a positive prognostic factor (median survival 28.4months with belagenpumatucel-L versus 16.0months with placebo; HR 0.61, p=0.032). ConclusionsAlthough the overall trial did not meet its survival endpoint, improved survival for belagenpumatucel-L is suggested in patients who were randomised within 12weeks of completion of chemotherapy and in those who had received prior radiation. Further studies of belagenpumatucel-L in NSCLC are warranted.

Gene expression profiling of peripheral blood mononuclear cells during treatment with a gene-modified allogeneic tumor cell vaccine in advanced renal cell cancer: tumor-induced immunosuppression and a possible role for NF-κB.

Tumor-induced immunosuppression remains a major challenge for immunotherapy of cancer patients. To further elucidate why an allogeneic gene-modified [interleukin-7 (IL-7)/CD80-cotransfected] renal cell cancer (RCC) vaccine failed to induce clinically relevant TH-1-polarized immune responses, peripheral blood mononuclear cells from enrolled study patients were analyzed by gene expression profiling (GEP) both prior and after vaccination. At baseline before vaccination, a profound downregulation of gene signatures associated with antigen presentation, immune response/T cells, cytokines/chemokines and signaling/transcription factors was observed in RCC patients as compared to healthy controls. Vaccination led to a partial reversion of preexisting immunosuppression, however, GEP indicated that an appropriate TH-1 polarization could not be achieved. Most interestingly, our results suggest that the nuclear factor-kappa B signaling pathway might be involved in the impairment of immunological responsiveness and the observed TH-2 deviation. In summary, our data suggest that GEP might be a powerful tool for the prediction of immunosuppression and the monitoring of immune responses within immunotherapy trials.

516. A Phase III Study of Belagenpumatucel-L, an Allogeneic Tumor Cell Vaccine, as Maintenance Therapy for Non-Small Cell Lung Cancer

516. A Phase III Study of Belagenpumatucel-L, an Allogeneic Tumor Cell Vaccine, as Maintenance Therapy for Non-Small Cell Lung Cancer

Vaccination therapy for non-small-cell lung cancer

Recent advances in our understanding of cancer immunology resulted in the development of promising therapeutic agents for either nonantigen-specific immunotherapy, for example, monoclonal antibodies targeting immune checkpoints on the T-cell lymphocyte, and antigen-specific immunotherapy or vaccination. Here, we review the recently reported results from randomized controlled trials (RCTs) with the latter approach. Several trials indicated feasibility, safety, and potential for better patient outcomes. In resected early stage non-small-cell lung cancer, a phase II RCT with the MAGE-A3 vaccine showed a trend for improved disease-free interval (hazard ratio 0.75), now further evaluated in the large MAGRIT (MAGE-A3 as Adjuvant NSCLC Immunotherapy Trial) study. In stage III after chemoradiotherapy, the phase III START (Stimulating Targeted Antigenic Responses to NSCLC) trial with L-BLP25 vaccine resulted in a remarkable 10-month improvement in median survival in the concurrent chemoradiotherapy subgroup. In the advanced setting, the phase III study with the allogeneic tumor cell vaccine belagenpumatucel-L did not improve survival in the whole study, but interesting effects were seen in subgroups. Recent non-small-cell lung cancer vaccination trials did not meet their primary endpoint, but showed clear patient benefits in subgroup analyses. Confirmatory trials and identifying patients who will benefit using predictive factors, will hopefully bring these approaches in the clinic in the near future.

Status of Active Specific Immunotherapy for Stage II, Stage III, and Resected Stage IV Colon Cancer

Colorectal cancer is one of the most prevalent types of cancer worldwide and a leading cause of cancer-related mortality. The reported incidence of recurrent disease increases with the stage, and the 5-year survival rate is poor, especially for tumors with regional spread and for late-stage disease. This has prompted the search for more advanced treatment options, and therefore avenues for clinical testing of rationally designed immunotherapeutic strategies, including vaccination, as adjuvant treatment are being explored. In this review, we discuss the study design and results of the clinical trials that have been conducted using active specific immunotherapy in colorectal cancer, including autologous and allogeneic tumor cell vaccines, peptide vaccines, viral-vector-based vaccines, and dendritic-cell-based vaccines as well as some future recommendations.

Combining active immunotherapy with immune checkpoint blockade for the treatment of advanced prostate cancer

Combination immunotherapy is emerging as a promising approach for the treatment of advanced prostate cancer. This research highlight discusses the combination of a PSA-directed poxviral vaccine and a monoclonal antibody blocking an important immune checkpoint molecule to treat men with metastatic castration-resistant prostate cancer. The results demonstrate feasibility and safety, as well as intriguing clinical responses to this combination therapy.

Abstract 5364: Correlation of immune responses and overall survival in a phase II study of belagenpumatucel-L, an allogeneic tumor cell vaccine, in non-small cell lung cancer (NSCLC)

Abstract This study examines the correlative/predictive value of cellular- and humoral-mediated immune response on the clinical responsiveness of patients who received belagenpumatucel-L, a therapeutic vaccine comprised of 4 TGF-β2 antisense gene-modified allogeneic non-small cell lung cancer (NSCLC) cell lines in a phase II clinical trial in which subjects with stage III/IV NSCLC received intradermal injections of the vaccine every 4-8 weeks. We performed assays of cellular (ELISPOT) and humoral (antibody ELISA) immunity on 36 subjects in the trial and correlated these data with the long term assessment of overall survival. All but one subject in the study showed an increase in immune reactivity in at least one of the cellular or humoral assays. Eleven subjects who demonstrated an aggregate increase in both cellular and humoral immune reactivity (positive by three of four criteria tested) had a median survival of 32.5 months (95% CI, 25.2 to 39.8). This was significantly better than the median survival of only 11.6 months (95% CI, 5.6 to 17.6) for the 25 subjects who showed an increase in one or none of the measured immune parameters (p=0.015, log-rank test). The demonstration of a statistically significant correlation between cellular and humoral immune responses and overall survival in subjects treated with belagenpumatucel-L suggest that both compartments of the immune system likely impact the clinical response and are important for the induction of clinically significant antitumor immunity by the vaccine. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5364. doi:1538-7445.AM2012-5364

Lung Cancer Vaccines

To date, in lung cancer, early attempts to modulate the immune system via vaccine-based therapeutics have been unsuccessful. An improved understanding of tumor immunology has facilitated the production of more sophisticated lung cancer vaccines. It is anticipated that it will likely require multiple epitopes of a diverse set of genes restricted to multiple haplotypes to generate a truly effective vaccine that is able to overcome the various immunologic escape mechanisms that tumors employ. Other issues to overcome include optimal patient selection, which adjuvant agent to use, and how to adequately monitor for an immunologic response. This review discusses the most promising vaccination strategies for non-small cell lung cancer including the allogeneic tumor cell vaccine belagenpumatucel-L, which is a mixture of 4 allogeneic non-small cell lung cancer cell lines genetically modified to secrete an antisense oligonucleotide to transforming growth factor β2 and 3 other target protein-specific vaccines designed to induce responses against melanoma-associated antigen A3, mucin 1, and epidermal growth factor.

Current status of immunological therapies for prostate cancer.

Considerable progress has been made in prostate cancer immunotherapy over the last year, and two agents have completed phase III testing. This review will discuss the most promising immune-directed strategies in development for prostate cancer, outlining interventions that mitigate tumor-induced tolerance and highlighting several combination immunotherapy approaches. A pivotal phase III study using Sipuleucel-T, an autologous prostatic acid phosphatase (PAP)-loaded dendritic cell immunotherapy, in men with metastatic castration-resistant prostate cancer (CRPC) demonstrated a survival advantage over placebo. By contrast, two phase III studies of GVAX, an allogeneic tumor cell vaccine, in a similar patient population failed to show a survival benefit of GVAX or GVAX/docetaxel over standard docetaxel/prednisone. Other strategies currently in clinical development include the ProstVac poxviral vaccine, a PAP-encoding DNA vaccine, and immune checkpoint inhibitory approaches. Although Sipuleucel-T may receive FDA approval for patients with metastatic CRPC, challenges remain in identifying immunotherapy strategies that overcome immune tolerance, especially when disease burden is substantial. An emerging paradigm focuses on using immunotherapy together with checkpoint antagonists or in combination with conventional therapies in patients with early-stage disease. Such approaches are likely to yield optimal results, but must carefully be explored in well designed phase II studies before moving forward.

Phase II Study of Belagenpumatucel-L, a Transforming Growth Factor Beta-2 Antisense Gene-Modified Allogeneic Tumor Cell Vaccine in Non–Small-Cell Lung Cancer

Belagenpumatucel-L is a nonviral gene-based allogeneic tumor cell vaccine that demonstrates enhancement of tumor antigen recognition as a result of transforming growth factor beta-2 inhibition. We performed a randomized, dose-variable, phase II trial involving stages II, IIIA, IIIB, and IV non-small-cell lung cancer patients. Each patient received one of three doses (1.25, 2.5, or 5.0 x 10(7) cells/injection) of belagenpumatucel-L on a monthly or every other month schedule to a maximum of 16 injections. Immune function, safety, and anticancer activity were monitored. Seventy-five patients (two stage II, 12 stage IIIA, 15 stage IIIB, and 46 stage IV patients) received a total of 550 vaccinations. No significant adverse events were observed. A dose-related survival difference was demonstrated in patients who received > or = 2.5 x 10(7) cells/injection (P = .0069). Focusing on the 61 late-stage (IIIB and IV) assessable patients, a 15% partial response rate was achieved. The estimated probabilities of surviving 1 and 2 years were 68% and 52%, respectively for the higher dose groups combined and 39% and 20%, respectively, for the low-dose group. Immune function was explored in the 61 advanced-stage (IIIB and IV) patients. Increased cytokine production (at week 12 compared with patients with progressive disease) was observed among clinical responders (interferon gamma, P = .006; interleukin [IL] -6, P = .004; IL-4, P = .007), who also displayed an elevated antibody-mediated response to vaccine HLAs (P = .014). Furthermore, positive enzyme-linked immunospot reactions to belagenpumatucel-L showed a correlation trend (P = .086) with clinical responsiveness in patients achieving stable disease or better. Belagenpumatucel-L is well tolerated, and the survival advantage justifies further phase III evaluation.

Phase II study of a TGF-β2 antisense gene modified allogeneic tumor cell vaccine (Lucanix) in advanced NSCLC

7018 Background: Lucanix (L) is a non-viral gene based allogeneic tumor cell vaccine which demonstrates enhancement of tumor antigen recognition as a result of Transforming Growth Factor (TGF-β2) inhibition. Methods: We performed a randomized dose variable phase II trial involving stage IIIB/IV non small cell lung cancer (NSCLC). Each patient received one of 3 doses (1.25, 2.5, 5.0x107 cells/injection) of L, given intradermally, to a maximum of 16 injections either monthly or every other month. Immune function, safety and anticancer activity were monitored. Results: Sixty-one patients (15 IIIB/ 46 IV; 51/61 (84%) ≥ prior cytotoxic therapy), received a total of 417 vaccinations. No significant (≥ grade 3) adverse events probably or definitely associated with administration of the vaccine were observed. A dose-related survival difference was demonstrated in patients who received ≥ 2.5 × 107 cells/injection versus those who received <2.5 × 107 cells/injection (p=0.0151). The percent of patients surviving 1 and 2 years was 61% and 52% for the high dose group and 40% and 13% for the low dose group. Fifteen percent of patients achieved a partial response. Cytokine production (IFN-γ, p=0.006; IL-6, p=0.004; IL4, p=0.007) was induced, antibody mediated response to vaccine HLA antigen was observed (p=0.014) and cell mediated response showed a correlation trend (p=0.086) in patients achieving stable disease or partial response (15%) compared to those with progressive disease. Conclusions: In conclusion, L is safe and well tolerated. A survival advantage is suggested in patients who receive ≥ 2.5x107 cells/injection thereby supporting the justification for further phase III evaluation. Phase III investigation is recommended. [Table: see text]

1104. Phase II Study of Lucanix™ a Transforming Growth Factor β2 (TGF-β2) Antisense Gene Modified Allogeneic Tumor Cell Vaccine in Non Small Cell Lung Cancer (NSCLC)

Lucanix™ is a non-viral gene based allogeneic tumor cell vaccine. Preclinical studies demonstrate enhancement of tumor antigen recognition as a result of TGF-β2 inhibition.We performed a randomized dose variable phase II trial involving stage II, IIIA, IIIB and IV NSCLC. Each patient received one of 3 doses (1.25, 2.5, 5.0x107 cells/injection) of Lucanix™ on a monthly or every other month schedule to a maximum of 16 injections. Immune function, safety and anticancer activity were monitored. Seventy five patients (2 stage II, 12 IIIA, 15 IIIB, 46 IV), received a total of 550 vaccinations. No significant (≥ grade 3) adverse events probably or definitely associated with administration of the vaccine were observed. A dose-related survival difference was demonstrated in patients who received ≥ 2.5 × 107 cells/injection versus those who received <2.5 × 107 cells/injection (p=0.0069). Focusing on the sixty- one late stage (IIIb/IV) evaluable patients, a 15% partial response rate was achieved. The estimated probabilities of surviving 1 and 2 years were 68% (95% CI: 55%, 80%) and 52% (95% CI: 35%, 68%) for the two higher-dose groups combined and was 39% (95% CI: 22%, 66%) and 20% (95% CI: 4%, 36%) for the low dose group. Immune function was explored in the 61 advanced stage (IIIB/IV) patients. Cytokine production (IFN-γ, p=0.006; IL-6, p=0.004; IL4, p=0.007) was induced, antibody mediated response to vaccine HLA antigen was observed (p=0.014) and cell mediated response showed a correlation trend (p=0.086) in patients achieving stable disease or partial response compared to those with progressive disease. In conclusion, Lucanix™ is safe and well tolerated. A survival advantage is suggested in patients who receive ≥ 2.5x107 cells/ injection thereby supporting the justification for further phase III evaluation. Lucanix™ is a non-viral gene based allogeneic tumor cell vaccine. Preclinical studies demonstrate enhancement of tumor antigen recognition as a result of TGF-β2 inhibition. We performed a randomized dose variable phase II trial involving stage II, IIIA, IIIB and IV NSCLC. Each patient received one of 3 doses (1.25, 2.5, 5.0x107 cells/injection) of Lucanix™ on a monthly or every other month schedule to a maximum of 16 injections. Immune function, safety and anticancer activity were monitored. Seventy five patients (2 stage II, 12 IIIA, 15 IIIB, 46 IV), received a total of 550 vaccinations. No significant (≥ grade 3) adverse events probably or definitely associated with administration of the vaccine were observed. A dose-related survival difference was demonstrated in patients who received ≥ 2.5 × 107 cells/injection versus those who received <2.5 × 107 cells/injection (p=0.0069). Focusing on the sixty- one late stage (IIIb/IV) evaluable patients, a 15% partial response rate was achieved. The estimated probabilities of surviving 1 and 2 years were 68% (95% CI: 55%, 80%) and 52% (95% CI: 35%, 68%) for the two higher-dose groups combined and was 39% (95% CI: 22%, 66%) and 20% (95% CI: 4%, 36%) for the low dose group. Immune function was explored in the 61 advanced stage (IIIB/IV) patients. Cytokine production (IFN-γ, p=0.006; IL-6, p=0.004; IL4, p=0.007) was induced, antibody mediated response to vaccine HLA antigen was observed (p=0.014) and cell mediated response showed a correlation trend (p=0.086) in patients achieving stable disease or partial response compared to those with progressive disease. In conclusion, Lucanix™ is safe and well tolerated. A survival advantage is suggested in patients who receive ≥ 2.5x107 cells/ injection thereby supporting the justification for further phase III evaluation.

Influence of CD80, Interleukin-2, and Interleukin-7 Expression in Human Renal Cell Carcinoma on the Expansion, Function, and Survival of Tumor-Specific CTLs

A renal cell carcinoma (RCC) line, RCC-26, has been identified as a suitable candidate for development of an allogeneic tumor cell vaccine based on its expression of a variety of tumor-associated antigens (TAA). To improve immunogenicity, RCC-26 cells were genetically engineered to express CD80 alone or in combination with interleukin (IL)-2 or IL-7. The effect of these modifications on proliferation, function, and survival of autologous and allogeneic tumor-specific CTLs was assessed. RCC-26 sublines expressing different transgenes were tested for their capacity to reactivate cytokine secretion and cytotoxicity in autologous tumor-infiltrating lymphocytes, to improve proliferation and survival of tumor-associated T cells present in autologous peripheral blood, and to induce tumor-associated responses in naive allogeneic lymphocytes. The expression of several common TAA was quantitated in the RCC-26 sublines using reverse transcription-PCR to identify surrogate markers for immune monitoring in clinical trials. Gene-modified RCC-26 cells showed enhanced immunogenicity. CD80 expression was necessary to induce RCC-associated CTL in blood of healthy allogeneic donors. It also improved proliferation of autologous effector-memory T cells. Further enhancement was achieved with IL-2 through induction of the antiapoptosis protein Bcl-x(L). The candidate vaccine lines overexpressed several common TAA that are suitable markers for immune monitoring. RCC-26 cells coexpressing CD80 and cytokine transgenes display improved immunogenic characteristics, supporting their use as allogeneic tumor cell vaccines for HLA-A2-matched patients with metastatic RCC.

Therapeutic Vaccines for Colorectal Cancer

A number of cancer vaccine strategies for the treatment of colorectal cancer have entered clinical trials. Whole tumor cell vaccines have been developed from both patients’ autologous tumor cells as well as established allogeneic tumor cell lines. A vaccine consisting of autologous tumor cells along with bacillus Calmette-Guerin (BCG) has shown a potential clinical benefit in patients with stage II colon cancer. Other approaches using autologous tumor cells have involved transfection of primary tumor cells with cytokine genes. Allogeneic tumor cell vaccines have also been modified to express cytokine genes. Vectors have been studied extensively as a means of vaccine strategy. One tumor-associated antigen (TAA) that has been extensively studied in viral vector vaccines is carcinoembryonic antigen (CEA). A recombinant vaccinia virus containing the CEA transgene (rV-CEA) has been shown to elicit CEA-specific immune responses in advanced carcinoma patients. However, patients receiving multiple vaccinations had limited increases in CEA-specific responses by the third vaccination. This problem may be overcome by the use of non-replicating poxviruses, which have been shown in clinical trials to be safe and to elicit CEA-specific responses. However, recent clinical studies have shown that the optimal use of poxviruses is to prime with vaccinia, followed by boosts with avipox vectors. A recent randomized clinical trial showed that patients primed with rV-CEA and boosted with avipox-CEA had greater immune responses compared with patients receiving three 1-monthly avipox-CEA vaccinations followed by an rV-CEA vaccination. Furthermore, a statistically significant survival advantage was noted in the prime/boost arm. Ongoing studies are now incorporating the genes for costimulatory molecules along with TAA in these vectors. Another vaccine strategy involving TAA that is currently in clinical trials for colorectal cancer is the peptide vaccine. Dendritic cells (DCs) are considered to be the most potent antigen-presenting cell, thus providing an attractive modality for cancer vaccines. In addition to using DCs for peptide-based vaccines, a number of other strategies, including transfection with messenger RNA, have produced specific T-cell responses in clinical trials. In addition, several clinical trials using murine anti-idiotype antibodies as vaccines for patients with advanced colorectal cancer have shown both immunologic responses as well as clinical responses.