Dzubinski, Lynda

Abstract Purpose: To assess whether MUC1 peptide vaccine produces an immune response and prevents subsequent colon adenoma formation. Patients and Methods: Multicenter, double-blind, placebo-controlled randomized trial in individuals age 40 to 70 with diagnosis of an advanced adenoma ≤1 year from randomization. Vaccine was administered at 0, 2, and 10 weeks with a booster injection at week 53. Adenoma recurrence was assessed ≥1 year from randomization. The primary endpoint was vaccine immunogenicity at 12 weeks defined by anti-MUC1 ratio ≥2.0. Results: Fifty-three participants received the MUC1 vaccine and 50 placebo. Thirteen of 52 (25%) MUC1 vaccine recipients had a ≥2-fold increase in MUC1 IgG (range, 2.9–17.3) at week 12 versus 0/50 placebo recipients (one-sided Fisher exact P < 0.0001). Of 13 responders at week 12, 11 (84.6%) responded to a booster injection at week 52 with a ≥2-fold increase in MUC1 IgG measured at week 55. Recurrent adenoma was observed in 31 of 47 (66.0%) in the placebo group versus 27 of 48 (56.3%) in the MUC1 group [adjusted relative risk (aRR), 0.83; 95% confidence interval (CI), 0.60–1.14; P = 0.25]. Adenoma recurrence occurred in 3/11 (27.3%) immune responders at week 12 and week 55 (aRR, 0.41; 95% CI, 0.15–1.11; P = 0.08 compared with placebo). There was no difference in serious adverse events. Conclusions: An immune response was observed only in vaccine recipients. Adenoma recurrence was not different than placebo, but a 38% absolute reduction in adenoma recurrence compared with placebo was observed in participants who had an immune response at week 12 and with the booster injection.

Abstract Background: Immunoprevention via targeting antigens aberrantly expressed on colorectal cancers and adenomatous polyps offers the potential for a less invasive prevention strategy than endoscopic surveillance. Specificity of the immune response and long-term memory provide the potential for prolonged protection. Leveraging the infrastructure of the NCI-funded Cancer Prevention Network (CPN) consortium, we are conducting a double-blind randomized trial in individuals with a diagnosis of advanced colorectal adenomas within the previous year. We are evaluating MUC1 vaccine with the TLR-3 agonist polyICLC as an adjuvant, for its immunogenicity, ability to elicit immune memory and prevent recurrence of colorectal adenomas. Aims: We previously reported on the vaccine immunogenicity at week 12 (vaccine administered at 0, 2, and 10 weeks) compared to placebo. Here we report the ability of the vaccine to elicit long-term memory by measuring increase in anti-MUC1 antibody levels following a booster administered at one year. Methods: Subjects with endoscopically resected advanced adenoma (defined as ≥1cm, tubululovillous or villous histology, or with high grade dysplasia) were randomized. The primary endpoint was the response to the vaccine at week 12 assessed by monitoring anti-MUC1 IgG antibody titer ratio defined as t12/t0, where t0 was the titer pre-vaccination, and t12 was the titer at week 12. The key secondary endpoint was to assess anti-MUC1 IgG response at week 55 to a booster at week 52 in the vaccine arm compared to placebo. Results: 102 eligible subjects were randomized at 6 centers, 52 received MUC1 vaccine and 50 placebo. The mean age was 59.4±7.0 (range 40-70), 60.8% male, 88.2% white, and 18.6% Hispanic or Latino ethnicity. At 12 weeks the IgG ratio was ≥2.0 in 13/52 (25%) of individuals receiving vaccine (ratio range -0.5-17.3), vs. 0/50 in placebo group (2-sided p=.0001), and was ≥1.5 in 19/52 (36.5%) individuals receiving vaccine compared to 1/50 (2%) in placebo group (P<.0001). To evaluate immune memory, 1-year booster data available for 95 patients (51-MUC1, 44-placebo) were analyzed. 10/13 (76.9%) of the week 12 vs. week 0 vaccine responders showed a response at week 52 vs. baseline and 11/13 (84.6%) at week 55 vs. week 52. Using an IgG ratio of 2 (per-protocol), the response rate was 33% for MUC1 vs. 5% for placebo (1-sided p=0.0003). Using a ratio of 1.5 yielded similar results (37% MUC1 vs. 9% Placebo (1-sided p=0.0008). The MUC1 arm had significantly higher IgG at week 52 (1-sided p=0.0294), week 55 (1-sided p=0.0048), and significantly higher week 55 to week 52 IgG ratio values (1-sided p=0.0293). Conclusions: Subjects with a recent history of advanced adenoma receiving a MUC1 vaccine compared with a placebo were significantly more likely to develop an immune response at week 12, confirming the vaccine’s immunogenicity, and to respond again at week 55 to a booster injection on week 52, confirming the vaccine’s ability to elicit immune memory. Follow-up colonoscopy to evaluate the vaccine’s potential to lower adenomatous polyp recurrence rates are in progress. Citation Format: Olivera J. Finn, Lisa Boardman, Marcia Cruz-Correa, Ajay Bansal, David Kastenberg, Chin Hurr, Sharon Kaufman, Colleen Akerley, Lynda Dzubinski, April Felt, Karrie Fursa, L.M. Rodriguez, Ellen Richmond, Asad Umar, Eva Szabo, John McKolanis, Ryan McMurray, Nathan Foster, Andres Salazar, Paul Limburg, Robert Schoen. Randomized, double-blind, placebo-controlled trial of preventative MUC1 vaccine in patients with newly diagnosed advanced adenomas: Results from one-year booster [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT236.

Abstract Background: Immunotherapy targeting tumor-associated antigens aberrantly expressed on colorectal cancers and adenomatous polyps offers the potential for a relatively non-invasive and non-toxic prevention strategy, and because of the specificity of the immune response and its long-term memory, the potential for prolonged protection. In a double-blind randomized trial in patients with a diagnosis of advanced colorectal adenomas within the previous year, we are evaluating MUC1 vaccine with the TLR-3 agonist polyICLC (Hiltonol®) as an adjuvant, for its immunogenicity and effect on colorectal adenoma recurrence at follow up colonoscopy. Aim: We report on a primary endpoint, MUC1 immunogenicity at week 12 (following vaccine or placebo administration at 0, 2, and 10 weeks), and on determinants of the immune response and vaccine toxicity. Methods: Subjects with an advanced adenoma (defined as ≥1cm, tubulovillous or villous histology, or with HGD) were randomized. Response to the vaccine was assessed by monitoring IgG anti-MUC1 antibody titer ratio; defined as t12/t0, where t0 is the initial titer measured prior to vaccination, and t12 is the titer drawn at 12 weeks. A ratio of 2.0 was used as the primary definition of a significant immune response. T Regulatory and myleoid derived suppressor cell (MDSC) levels at baseline were assessed in relation to vaccine response. Adverse events (AEs) were recorded according to NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Results: 102 subjects were randomized at 6 centers, 52 received MUC1 vaccine and 50 placebo. Subjects had a mean age of 59.4±7.0 (range 40-70) years, 60.8% were male, 88.2% were white, and 18.6% Hispanic or Latino. At 12 weeks the IgG ratio was ≥2.0 in 13/52 (25%) of patients receiving vaccine (ratio range 2.9-17.3), vs. 0/50 in placebo group (P=.0001), and was ≥1.5 in 19/52 (36.5%) of patients receiving vaccine compared to 1/50 (2%) in placebo group (P<.0001). In the vaccinated group, the IgG ratio was ≥2.0 in 45% of women (9/20) vs. 12.5% of men (4/32) (P=0.009) and ≥1.5 in 55% of women (11/20) vs. 25% of men (8/32) (P=0.03). In the vaccinated group, reduced levels of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) pre-vaccination were associated with response, 0.2±0.1 among responders (n=13) vs. 0.8±1.1 among non-responders (N=39) (p=0.0006) whereas monocytic MDSC and T regulatory cells (CD4+CD25, Foxp3) were not. There were no grade 3 adverse events (AE) possibly or probably related to the vaccine. The most common AE was an injection site reaction (grade 1 or 2) which occurred in 80.8% (n=42/52) in vaccine group vs. 6.0% in the placebo group (3/50). Conclusions: Subjects with an advanced adenoma receiving MUC1 vaccine compared with a placebo are significantly more likely to develop an anti-IgG MUC1 immune response at 12 weeks. Women and subjects with lower circulating PMN-MDSC levels at baseline were more likely to respond. The vaccine was well tolerated. Follow up for the effect of the vaccine on adenomatous polyp recurrence is ongoing. Citation Format: Robert E. Schoen, Lisa A. Boardman, Marcia Cruz-Correa, Ajay Bansal, Pamela L. Beatty, David Kastenberg, Chin Hur, Lynda Dzubinski, Luz Rodriguez, Andres Salazar, John McKolanis, Drew Seisler, Nathan R. Foster, May-Yin Polley, Paul J. Limburg, Olivera J. Finn. Randomized, double-blind, placebo-controlled immunoprevention trial with MUC1 vaccine in patients with newly diagnosed advanced adenomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-305.