William Shingler

Vaccination of Metastatic Renal Cancer Patients with MVA-5T4: A Randomized, Double-Blind, Placebo-Controlled Phase III Study

Purpose: The TroVax Renal Immunotherapy Survival Trial was a randomized, placebo-controlled phase III study that investigated whether modified vaccinia Ankara encoding the tumor antigen 5T4 (MVA-5T4) prolonged survival of patients receiving first-line standard-of-care (SOC) treatment for metastatic renal cell cancer. Experimental Design: Patients with metastatic clear cell renal cancer, prior nephrectomy, and good or intermediate prognosis were randomized 1:1 to receive up to 13 immunizations of MVA-5T4/placebo in combination with either sunitinib, interleukin-2 or interferon-α. The primary end point was overall survival. Secondary end points included progression-free survival, overall response rate, and safety. Results: Seven hundred thirty-three patients were recruited (365 MVA-5T4 and 368 placebo). Treatment arms were well balanced for SOC and prognosis. No significant difference in the incidence of adverse events or serious adverse events was observed. No significant difference in overall survival was evident in the two treatment arms (median 20.1 months MVA-5T4 versus 19.2 months placebo; P = 0.55). The magnitude of the 5T4-specific antibody response induced by vaccination with MVA-5T4 was associated with enhanced patient survival. Furthermore, exploratory analyses suggested a number of pretreatment hematologic factors that could identify patients who derive significant benefit from this vaccine. Conclusion: MVA-5T4 in combination with SOC was well tolerated, but no difference in survival was observed in the overall study population. Exploratory analyses indicate that there may be subsets of patients who could gain significant benefit from MVA-5T4, but such results would need to be confirmed in future randomized clinical studies. Clin Cancer Res; 16(22); 5539–47. ©2010 AACR.

Vaccination of Colorectal Cancer Patients with Modified Vaccinia Ankara Encoding the Tumor Antigen 5T4 (TroVax) Given Alongside Chemotherapy Induces Potent Immune Responses

Purpose: The attenuated strain of vaccinia virus, modified vaccinia Ankara (MVA) encoding the tumor antigen 5T4 (TroVax), has been evaluated in an open-label phase II study in metastatic colorectal cancer patients. The primary objective was to assess the safety and immunogenicity of TroVax injected before, during, and after treatment with cycles of 5-fluorouracil, folinic acid, and oxaliplatin. Experimental Design: TroVax was administered to 17 patients with metastatic colorectal cancer. In total, 11 patients were considered to be evaluable for assessment of immunologic responses having received a total of six injections of TroVax, administered before, during, and following completion of chemotherapy. Antibody and cellular responses specific for 5T4 and MVA were monitored throughout the study. Results: Administration of TroVax alongside 5-fluorouracil, folinic acid, and oxaliplatin was safe and well tolerated with no serious adverse events attributed to TroVax. Ten of the 11 evaluable patients mounted 5T4-specific antibody responses with titers ranging from 10 to >1,000. IFNγ enzyme-linked immunospot responses specific for 5T4 were detected in 10 patients with precursor frequencies exceeding 1 in 1,000 peripheral blood mononuclear cells in 4 patients. Of the 11 evaluable patients, 6 had complete or partial responses. 5T4-specific immune responses, but not MVA-specific immune responses, correlated with clinical benefit. Conclusions: Potent 5T4-specific cellular and/or antibody responses were induced in all evaluable patients and were still detectable during the period in which chemotherapy was administered. These results suggest that TroVax can be added to chemotherapy regimens without any evidence of enhanced toxicity or reduced immunologic efficacy and may provide additional clinical benefit.

Phase II trial of Modified Vaccinia Ankara (MVA) virus expressing 5T4 and high dose Interleukin-2 (IL-2) in patients with metastatic renal cell carcinoma

BackgroundInterleukin-2 (IL-2) induces durable objective responses in a small cohort of patients with metastatic renal cell carcinoma (RCC) but the antigen(s) responsible for tumor rejection are not known. 5T4 is a non-secreted membrane glycoprotein expressed on clear cell and papillary RCCs. A modified vaccinia virus Ankara (MVA) encoding 5T4 was tested in combination with high-dose IL-2 to determine the safety, objective response rate and effect on humoral and cell-mediated immunity.Methods25 patients with metastatic RCC who qualified for IL-2 were eligible and received three immunizations every three weeks followed by IL-2 (600,000 IU/kg) after the second and third vaccinations. Blood was collected for analysis of humoral, effector and regulatory T cell responses.ResultsThere were no serious vaccine-related adverse events. While no objective responses were observed, three patients (12%) were rendered disease-free after nephrectomy or resection of residual metastatic disease. Twelve patients (48%) had stable disease which was associated with improved median overall survival compared to patients with progressive disease (not reached vs. 28 months, p = 0.0261). All patients developed 5T4-specific antibody responses and 13 patients had an increase in 5T4-specific T cell responses. Although the baseline frequency of Tregs was elevated in all patients, those with stable disease showed a trend toward increased effector CD8+ T cells and a decrease in Tregs.ConclusionV accination with MVA-5T4 did not improve objective response rates of IL-2 therapy but did result in stable disease associated with an increase in the ratio of 5T4-specific effector to regulatory T cells in selected patients.Trial registration numberISRCTN83977250

Vaccination of renal cell cancer patients with modified vaccinia ankara delivering the tumor antigen 5T4 (TroVax) alone or administered in combination with interferon-α (IFN-α): A phase 2 trial

Attenuated vaccinia virus, modified vaccinia Ankara (MVA) has been engineered to deliver the tumor antigen 5T4 (TroVax). MVA-5T4 has been evaluated in an open-label phase 2 trial in metastatic renal cell cancer patients in which the vaccine was administered alone or in combination with interferon-α-2b (IFN-α). The safety, immunologic, and clinical efficacy of MVA-5T4 with or without IFN-α was determined. Twenty-eight patients with metastatic renal cell cancer were treated with MVA-5T4 alone (13) or plus IFN-α (15). The 5T4-specific cellular and humoral responses were monitored throughout the study. Clinical responses were assessed by measuring changes in tumor burden by computed tomography or magnetic resonance imaging scan. MVA-5T4 was well tolerated with no serious adverse event attributed to vaccination. Of 23 intent-to-treat patients tested for immune responses postvaccination, 22 (96%) mounted 5T4-specific antibody and/or cellular responses. One patient treated with MVA-5T4 plus IFN-α showed a partial response for >7 months, whereas an additional 14 patients (7 receiving MVA-5T4 plus IFN and 7 receiving MVA-5T4 alone) showed periods of disease stabilization ranging from 1.73 to 9.60 months. Median progression free survival and overall survival for all intent-to-treat patients was 3.8 months (range: 1 to 11.47 mo) and 12.1 months (range: 1 to 27 mo), respectively. MVA-5T4 administered alone or in combination with IFN-α was well tolerated in all patients. Despite the high frequency of 5T4-specific immune responses, it is not possible to conclude that patients are receiving clinical benefit. The results are encouraging and warrant further investigation.

Vaccination of Renal Cell Cancer Patients with Modified Vaccinia Ankara Delivering Tumor Antigen 5T4 (TroVax) Administered with Interleukin 2: A Phase II Trial

Purpose: The attenuated vaccinia virus modified vaccinia ankara (MVA) has been engineered to deliver the tumor antigen 5T4 (TroVax). TroVax has been evaluated in an open-label phase II trial in metastatic renal cell cancer patients in which the vaccine was administered in combination with interleukin-2 (IL-2). The safety, immunologic, and clinical efficacy of TroVax in combination with IL-2 was determined. Experimental Design: Twenty-five patients with metastatic renal cell cancer were treated with TroVax plus IL-2. 5T4-specific cellular and humoral responses were monitored throughout the study. Clinical responses were assessed by measuring changes in tumor burden by computed tomography or magnetic resonance imaging scan. Results: TroVax was well tolerated with no serious adverse event attributed to vaccination. Of 25 intention-to-treat patients, 21 mounted 5T4-specific antibody responses. Two patients showed a complete response for >24 months and one a partial response for >12 months. Six patients had disease stabilization from 6 to >21 months. Median progression-free survival (PFS) and overall survival (OS) were >3.37 months (range, 1.50->24.76) and >12.87 months (range, 1.90->24.76), respectively. A statistically significant relationship was detected between the magnitude of 5T4-specific antibody responses and PFS and OS. Conclusion: TroVax in combination with IL-2 was safe and well tolerated in all patients. The high frequency of 5T4-specific immune responses and good clinical response rate are encouraging and warrant further investigation.

Vaccination of Patients with Metastatic Renal Cancer with Modified Vaccinia Ankara Encoding the Tumor Antigen 5T4 (TroVax) Given Alongside Interferon-α

Approximately 90% of renal cell tumors overexpress the tumor antigen 5T4. The attenuated strain of vaccinia virus, modified vaccinia Ankara, has been engineered to express 5T4 (TroVax). We conducted an open-label phase 1/2 trial in which TroVax was administered alongside interferon-α (IFNα) to 11 patients with metastatic renal cell carcinoma. Antigen-specific cellular and humoral responses were monitored throughout the study, and clinical responses were assessed by measuring the changes in tumor burden by computed tomography scan (Response Evaluation Criteria In Solid Tumors). The primary objective was to assess the safety, immunogenicity, and efficacy of TroVax when given alongside IFNα. Treatment with TroVax plus IFNα was well tolerated with no serious adverse events attributed to TroVax. All 11 patients mounted 5T4-specific antibody responses and 5 (45%) mounted cellular responses. No objective tumor responses were seen, but the overall median time to progression (TTP) of 9 months (range: 2.1 to 26+ mo) was longer than expected for IFNα alone. For the 10 clear cell patients the TTP ranged from 3.9 to 26+ months, with a median TTP of 10.4 months. The high frequency of 5T4-specific immune responses and prolonged median TTP for clear cell patients compared with that expected for IFNα alone is encouraging and warrants further investigation.

Cross-trial analysis of immunologic and clinical data resulting from phase I and II trials of MVA-5T4 (TroVax) in colorectal, renal, and prostate cancer patients.

The attenuated vaccinia virus MVA has been engineered to deliver the tumor antigen 5T4 (MVA-5T4; TroVax), a surface glycoprotein expressed by most solid tumors. MVA-5T4 has been tested in 2 phase I/II and 7 phase II clinical trials in colorectal (4 trials), renal (4 trials), and prostate (1 trial) advanced cancer patients. Data have been collated from all 9 studies and used to investigate the magnitude and kinetics of 5T4-specific antibody responses after vaccination and to identify potential associations between the immune response and patient survival. Antibody responses specific for the 5T4 tumor antigen and the MVA viral vector were quantified in plasma samples taken from cancer patients before and after the treatment with MVA-5T4. Immunologic and survival data were analyzed using proportional hazards regression adjusting for age and gender. Both survival and immunologic response data were available for 189 patients with colorectal (n=73), renal (n=89), and prostate (n=27) cancer. Before the treatment with MVA-5T4, 5T4-specific antibody levels were significantly elevated in cancer patients compared with healthy donors. After MVA-5T4 administration, 5T4-specific antibody responses increased significantly and peaked after 3 to 4 vaccinations. Exploratory analyses showed significant associations between 5T4 antibody responses and overall survival across all 9 trials and in patients with colorectal cancer. The 5T4-specific antibodies were present at higher levels in cancer patients compared with healthy donors and increased significantly after treatment with MVA-5T4. Although the studies were uncontrolled, there were encouraging signs of activity which is associated with the magnitude of 5T4-specific antibody responses.

MVA-5T4-induced immune responses are an early marker of efficacy in renal cancer patients

Few immunotherapy compounds have demonstrated a direct link between the predicted mode of action of the product and benefit to the patient. Since cancer vaccines are thought to have a delayed therapeutic effect, identification of the active moiety may enable the development of an early marker of efficacy. Patients with renal cancer and requiring first-line treatment for metastatic disease were randomized 1:1 to receive MVA-5T4 (TroVax®) or placebo alongside Sunitinib, IL-2 or IFN-α in a multicentre phase III trial. Antibody responses were quantified following the 3rd and 4th vaccinations. A surrogate for 5T4 antibody response (the immune response surrogate; IRS) was constructed and then used in a survival analysis to evaluate treatment benefit. Seven hundred and thirty-three patients were randomized, and immune responses were assessed in 590 patients. A high 5T4 antibody response was associated with longer survival within the MVA–5T4-treated group. The IRS was constructed as a linear combination of pre-treatment 5T4 antibody levels, hemoglobin and hematocrit and was shown to be a significant predictor of treatment benefit in the phase III study. Importantly, the IRS was also associated with antibody response and survival in an independent dataset comprising renal, colorectal and prostate cancer patients treated with MVA–5T4 in phase I–II studies. The derivation of the IRS formed part of an exploratory, retrospective analysis; however, if confirmed in future studies, the results have important implications for the development and use of the MVA–5T4 vaccine and potentially for other similar vaccines.

Identification and functional validation of MHC class I epitopes in the tumor-associated antigen 5T4.

UNLABELLED The cancer vaccine TroVax, modified vaccinia Ankara encoding the tumor-associated antigen 5T4, has been tested in phase I and II studies in colorectal cancer patients. Monitoring of 5T4-specific immune responses in patients receiving TroVax is critical since it could inform future refinements to the therapeutic or provide a surrogate marker of clinical efficacy. Tumor-specific cytotoxic T lymphocyte (CTL) are considered to be a key component of an effective anti-cancer immune response. Though numerous techniques have been employed to identify CTL epitopes, many are labor intensive, of variable reliability or biased toward common alleles such as human leukocyte antigen (HLA)-A2. A new high-throughput technique, iTopia, enables peptides to be evaluated on the basis of their physical binding properties for HLA alleles. This technique has been utilized to rapidly screen a panel of overlapping peptides, spanning the length of 5T4. Initially, peptides which bound to four class I alleles (A*0101, A*0201, A*0301 and B*0702) were identified and their physical binding characteristics assessed further by analysis of relative affinity and complex stability. 46 putative CTL epitopes have been identified which bind to at least one of the four HLA alleles. Using PBMCs from patients vaccinated with TroVax, we have used the interferon gamma (IFN gamma) ELISpot assay to validate one predicted A1 and two A2 epitopes. CONCLUSION iTopia represents a rapid and high-throughput technique to identify CTL epitopes.

Abstract CT106: A phase I/IIa study of IMCgp100: Partial and complete durable responses with a novel first-in-class immunotherapy for advanced melanoma

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Background: IMCgp100 is an affinity-enhanced T cell receptor (TCR) specific for the HLA-A2 restricted melanoma gp100 peptide (YLEPGPVTA) fused to an anti-CD3 antibody fragment. Binding of IMCgp100 to melanoma cells redirects T cell cytotoxicity even in the presence of significant levels of PD-1 and PD-L1. Due to its high affinity, IMCgp100 enables T cells to kill HLA down-regulated melanoma cells otherwise invisible to natural T cell recognition. During phase I dose escalation of a weekly schedule, the Maximum Tolerated Dose (MTD) was 600ng/kg or 50mcg absolute dose. An expanded cohort is accruing at the MTD, and a second dose escalation was initiated to determine the MTD, toxicity and potential activity of a daily x 4 q3w schedule. Methods: Patients enrolled are HLA A2 positive, stage IV or unresectable stage III melanoma, with an ECOG Performance Status (PS) ≤1 and a lymphocyte count of ≥0.5×109/L. The phase II expansion of weekly dosing has a target of 10 patients; accrual will continue until a trio of evaluable biopsies are available from at least six patients. Dose escalation for the daily x 4 q3w regimen began at 10mcg/daily. One cycle is 6 weeks. Results: 16 patients have been treated weekly at MTD (600ng/kg or 50mcg). 63% were male, median age 58 yrs, ECOG PS 0 in 56%. All but one patient had stage IV disease. 63% of patients received ≥2 prior systemic therapies; some patients had prior ipilimumab (56%), RAFi (31%) and anti-PD1 or other immunotherapies (13%). Two patients were subsequently shown to be gp100 negative by IHC. Common toxicities included transient grade 3 pruritic rash and grade 2 pyrexia/edema. Lymphocytes migrated to skin and tumor as evidenced by biopsy analysis, accompanied by chemokine/cytokine release. Three partial responses (PR) and one complete response (CR) were observed and are still ongoing. Two PRs continue after >12 months, one, in an ipilimumab refractory patient continues after >3 months and a CR continues after >4 months; these include responses in the two ocular melanoma patients enrolled (long term PR and CR). Sites of response include lung, liver, lymphatic system and various soft tissues. For the daily x 4 regimen, the 20mcg daily dose is complete, toxicities are tolerable and escalation continues. Conclusions: Toxicities of IMCgp100 were consistent with the mode of action of the drug i.e. IMCgp100 mediated T cell mobilisation, activation and tumor killing. Objective durable responses were observed including in ocular melanoma patients. Additional patients are being accrued at 50mcg weekly. For the daily x 4 regimen, the 20mcg dose was completed, which equates to 80mcg every 3 weeks, or just over half the dose achievable in this period with weekly dosing. Dose escalation in the d x 4 regimen continues. Citation Format: Mark R. Middleton, Pippa Corrie, Mario Sznol, Jeffrey Infante, Clive Mulatero, Jeff Evans, Neil Steven, David Krige, William H. Shingler, Yvonne McGrath, Namir J. Hassan, Bent K. Jakobsen. A phase I/IIa study of IMCgp100: Partial and complete durable responses with a novel first-in-class immunotherapy for advanced melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT106. doi:10.1158/1538-7445.AM2015-CT106