Foster, Nathan R.

10529 Background: BAX mutations are associated with defective DNA mismatch repair (MMR) in human colon cancers. However, the impact of BAX inactivation upon tumor cell apoptosis and proliferation in vivo remain unknown. We analyzed and compared caspase-3 and Ki-67 expression in tumors with and without BAX mutations. Methods: TNM stage II and III (n= 377) colon carcinomas were studied from participants in a 5-FU-based adjuvant therapy trial. Archival tumors were analyzed for instability at the BAT26 mononucleotide locus using polymerase chain reaction and hMLH1, hMSH2 and hMSH6 by immunohistochemistry (IHC). Frameshift mutations in a tract of eight deoxyguanosines within BAX were analyzed. Expression of caspase-3 and Ki-67 proteins were analyzed by IHC. Results: Thirty-nine of 377 (10%) tumors showed defective MMR defined as instability at BAT26 and loss of either hMLH1, hMSH2 and/or hMSH6 proteins. BAX mutations were found in 20 of 37 (54%) MMR deficient tumors and in 1 of 50 (2%) tumors with intact MMR. Mean and median number of caspase-3-positive cells were increased in tumors with defective MMR (p= 0.04), but did not differ based upon BAX status [ Table ]. However, tumors with BAX mutations showed higher Ki-67 labeling indices compared to those with wild type BAX (p= 0.01)[ Table ]. Neither BAX mutations nor caspase-3- positive cells were prognostic in a univariate analysis. Tumors with lower Ki-67 extent had improved overall survival (p=0.06), but not DFS (p=0.24). Defective MMR (vs intact) was associated with better DFS in a multivariate analysis (p= 0.03). Conclusion: MMR deficient colon cancers show frequent BAX inactivation, yet have increased apoptotic rates as indicated by increased caspase-3 expressing tumor cells. BAX mutation was associated with hyperproliferation suggesting a growth advantage compared to wild type tumors. [Table: see text] No significant financial relationships to disclose.

7723 Background: It is critical that we understand the impact of patient, tumor, and treatment-related factors on patient prognosis for the proper design and analysis of Small Cell Lung Cancer (SCLC) trials. An analysis of 15 SCLC trials was performed to investigate and improve our understanding of several factors on OS. Methods: Data from 1623 patients (pts) were used. Age, gender, performance status (PS), tumor stage, body mass index (BMI), creatinine levels, hemoglobin levels, white blood cell counts (WBC), platelet counts, and bilirubin levels were tested for prognostic significance for OS both univariately and multivariately using a Cox Proportional Hazards Model. Models were stratified by protocol, and analyses carried out on the complete data available based on the selected covariates. Model discrimination (i.e., ability to discriminate patients with different survival times) was evaluated using the concordance index (COI). Results: Median follow-up was 63.1 months (range: 1.9 to 155.7). 58% and 42% of pts had extensive-stage or limited-stage SCLC, respectively. Patients with extensive-stage disease, PS>0, increased age, and male gender had significantly worse OS both univariately and multivariately. Patients with increased WBC had significantly worse OS univariately, however, WBC was not a significant predictor when adjusted for other factors. None of the other factors were prognostic for OS. Model discrimination improved by 6.3% when age, gender, PS, and stage were included in a model compared to a model with stage alone (COI improved from 0.63 to 0.67). Conclusions: Age, gender, PS and stage did better at predicting OS than stage alone. Further refinement of this model, including the addition of number of metastatic sites at baseline and treatment related factors, is currently underway. No significant financial relationships to disclose. [Table: see text]

7613 Background: Factors influencing the pattern of disease relapse after curative surgical resection in early stage NSCLC is unknown. We sought to evaluate the effect of tumor- and patient-related characteristics on the pattern of disease recurrence (local relapse and/or metastatic disease) and survival in relation to surgical resection for NSCLC. Methods: A consecutive retrospective series of 488 patients seen at Mayo Clinic Rochester who had complete resection of NSCLC between 1997 and 1998 was utilized. Cox proportional hazards model was used to evaluate the effect of age, gender, smoking status, TNM stage, number of lymph node (LN) involved, number of LN resected, and histopathologic diagnosis on RFS. Logistic regression was used to evaluate the effect on recurrence or death within the first 2 years after surgical resection. Results: Data on 342 patients with a median follow-up of 85 months (range: 0.1 to 162) are reported. 60% were male, and 81% had N0 stage at diagnosis. There were 26 (7.6%) never smokers. Median number of LN resected was 20 (interquartile range [IQR]: 14–29). Median age at surgery was 71 years (IQR: 64 to 76). A bi-modal pattern of local recurrence (N=62) after surgery for early stage NSCLC was observed, with 57% of patients having a local recurrence within 2 years and 21% of patients having a local recurrence from 5–7 years post-surgery. The median duration from surgery to first documented recurrence was 16 months (IQR: 8 to 39). While age, N stage, number of LN involved, and T stage were significant predictors of RFS univariately, only lesser LN resected (p=0.008), older age (p<0.0001) and higher T-stage (p=0.003) were significant adverse predictors of RFS in the multivariate analysis when adjusted for all factors. Higher T-Stage was associated with a significantly increased risk of recurrence or death within the first 2 years after surgical resection (p =0.004). Updated results using data from all 488 patients will be presented in the meeting. Conclusions: A trend towards a bimodal distribution of local recurrences after surgical resection of early stage NSCLC was observed. Increased number of LN resected, younger age and lower T stage were associated with better RFS. No significant financial relationships to disclose.

4578 Background: Gemcitabine is commonly used in patients with cholangiocarcinoma with a response rate of 20–30% and median overall survival of 6–10 months. Pemetrexed’s mechanism of action and tolerability in patients with hepatic dysfunction makes it a potential agent for cholangiocarcinoma. Methods: Patients with unresectable, previously untreated biliary tract cancers were eligible for participation. Patients received pemetrexed 500 mg/m2 IV over 10 minutes and gemcitabine 800 mg/m2 IV at 10 mg/m2/minute on days 1 and 15 of an every 4 week schedule with vitamin B12 and folate supplementation. The primary end-point is 6-month survival with a planned accrual of 59 patients. Results: 58 eligible patients are included in this analysis. 93% had metastatic disease. Median age was 61 (range: 40 - 81). Median follow-up was 6.5 months (range: 3.3 - 23.2). Median of 3 cycles of treatment was given (range: 1 - 10). Reasons for stopping treatment included disease progression (57%), adverse events (20%), refusal (17%), death on- study (4%), and other medical problems (2%). 6-month survival was 52% (95% CI: 40 - 68%). Median survival was 6.3 months (95% CI: 5.4 - 8.0 months) and median time-to-progression was 3.8 months (2.4 - 5.0). 46 of 58 patients (79%) experienced at least one grade 3+ AE (at least possible attribution), and 26 patients (45%) experienced at least one grade 4 AE (at least possible attribution), most of which were due to grade 4 neutropenia. Conclusions: This study shows similar results to what would be expected with gemcitabine alone. The addition of pemetrexed, as with other agents, has not significantly enhanced the activity of gemcitabine. Supported by NIH Grant CA25224- 18. [Table: see text] No significant financial relationships to disclose.

Abstract Difluoromethylornithine (DFMO), an inhibitor of polyamine synthesis, was shown to act synergistically with a NSAID for chemoprevention of colorectal neoplasia. We determined the efficacy and safety of DFMO plus aspirin for prevention of colorectal adenomas and regression of rectal aberrant crypt foci (ACF) in patients with prior advanced adenomas or cancer. A double-blinded, placebo-controlled trial was performed in 104 subjects (age 46–83) randomized (1:1) to receive daily DFMO (500 mg orally) plus aspirin (325 mg) or matched placebos for one year. All polyps were removed at baseline. Adenoma number (primary endpoint) and rectal ACF (index cluster and total) were evaluated at a one year colonoscopy. ACF were identified by chromoendoscopy. Toxicity was monitored, including audiometry. Eighty-seven subjects were evaluable for adenomas or ACF modulation (n = 62). At one year of treatment, adenomas were detected in 16 (38.1%) subjects in the DFMO plus aspirin arm (n = 42) versus 18 (40.9%) in the placebo arm (n = 44; P = 0.790); advanced adenomas were similar (n = 3/arm). DFMO plus aspirin was associated with a statistically significant reduction in the median number of rectal ACF compared with placebo (P = 0.036). Total rectal ACF burden was also reduced in the treatment versus the placebo arm relative to baseline (74% vs. 45%, P = 0.020). No increase in adverse events, including ototoxicity, was observed in the treatment versus placebo arms. While adenoma recurrence was not significantly reduced by one year of DFMO plus aspirin, the drug combination significantly reduced rectal ACF number consistent with a chemopreventive effect.

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&lt;.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: Smoking is the most common etiology for lung cancer. Smoking cessation, even when successful, does not eliminate risk of lung cancer. With inconsistent results of lung chemoprevention trials, an emerging area of interest is immunoprevention, in particular vaccines. MUC1 is a transmembrane glycoprotein aberrantly overexpressed in adenocarcinomas, including lung cancer. Abnormal MUC1 expression is also characteristic of premalignant lesions, including bronchial dysplasia and atypical adenomatous hyperplasia. This suggests that immunization with a MUC1 vaccine in the premalignant or high-risk setting, before the tumor and cytotoxic therapy could suppress the immune system, might be effective in inducing strong immunity and reducing cancer risk. Trial design: Leveraging the infrastructure of the NCI-funded Cancer Prevention Network (CPN) consortium, we are conducting a two-center pilot trial to evaluate co-primary endpoints: immunogenicity of the MUC1 peptide plus polyICLC adjuvant vaccine (assessed at 12 weeks) and safety (assessed at up to 24 weeks) in current and former smokers who are at high risk for lung cancer. 50 participants will be screened in order to have 40 evaluable participants for baseline and 12-week immunogenicity assessments. Eligibility: Smoking history of ≥30 pack-years and either current smoker (still smoking or quit &lt; 1 year prior to pre-registration) or former smoker (quit 1-15 years prior to pre-registration); ages 55-80 years; ECOG performance status ≤1; CT scan of the chest done ≤ 6 months prior to pre-registration showing either negative findings (no nodules) or solid or part-solid nodules &lt; 6 mm in size (consistent with &lt; 1% probability of malignancy, Lung-RADs Version 1.0). Exclusion criteria are standard. Immunogenicity and safety: MUC1 peptide plus polyICLC adjuvant vaccine will be administered at week 0, 2 and 10. The primary endpoint is anti-MUC1 IgG titer that is ≥2 fold higher at week 12 compared to baseline. Based on previous studies of this vaccine, we expect that 40 evaluable participants will provide 96% power to detect immunogenicity response rate of 15% versus 40% using a 2-sided test of proportions with type I error rate of 0.05. AEs and toxicities will be monitored for up to 24 weeks from the first vaccine. Secondary Objectives: We will explore differences, if any, in vaccine immunogenicity in current vs. former smokers. Smoking induces chronic inflammation (hallmark of cancer) associated with immunosuppression. We will evaluate pre-vaccination levels of circulating myeloid derived suppressor cells (MDSC) and correlate with the response to the vaccine. We will explore the impact, if any, of this vaccine on the markers of inflammation (hsCRP, IL-6) and the effect of baseline levels of these markers on the ability to successfully vaccinate. We will also assess the relationship between COPD status and immune response in current versus former smokers. The trial is open to accrual. Citation Format: Olivera J. Finn, Julie Ward, Tami Krpata, Lisa Bengtson, John McKolanis, Sharon Kaufman, Colleen Akerley, April Felt, Karrie Fursa, Anne Holland, Nathan Foster, Andres Salazar, Malgorzata Wojtowicz, Eva Szabo, Paul Limburg, David Midthun, Arjun Pennathur. A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer [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 CT222.

Abstract INTRODUCTION Participating in a clinical trial is a personal choice and an individual experience. Several barriers to recruitment of high risk men and women in chemoprevention trials have been documented; however, to our knowledge, there are no existing reports on participant satisfaction in such trials. Therefore, our aim was to describe and evaluate participants’ perception of their experience with participating in chemoprevention trials conducted by CPN by summarizing the 5-item “Was It Worth It” (WIWI) tool for each trial and across the trials, and according to race/ethnicity, sex, age, site, and organ of primary interest. METHODS Because participants who participate in chemoprevention trials tend to be at increased cancer-risk, but otherwise healthy, the WIWI tool can help answer simple questions about participants’ assessment of whether or not participation in such a trial was worthwhile. The WIWI tool was consistently administered at the end of the intervention period in each trial conducted by CPN; since 2003, 7 trials have completed the study intervention period and are included in the results reported here. RESULTS The scientific focus of the 7 trials targeted 5 organs: breast, colorectum, esophageal, hepatobiliary, and lung. Of the 485 participants registered to these 7 trials, 419 (86.4%) were non-Hispanic white, 19 (3.9%) non-Hispanic black, 32 (6.6%) Hispanic, 14 (2.9%) other race/ethnicity, and 1 (0.2%) unknown race/ethnicity; there were 120 (24.7%) females. In total, 446 (92.0%) participants completed the WIWI questionnaire at the end of their respective intervention period. Across the trials, 93% [95% CI] [90.6%, 95.4%] of the participants indicated that participation was worthwhile and 92% [89.5%, 94.5%] reported that they would participate again. Additionally, 414 (92.8%) participants indicated that they would recommend participating in the current research study to others, while 10 (2.3%) indicated that they would not and 22 (4.9%) were uncertain. Furthermore, several participants provided actionable feedback to the question “If there was one thing that could have been done to improve your experience in this research study, what would it be?” Participant feedback on overall changes in quality of life and on their expectations with participation in the trial was positive but more nuanced, varying according to trial and participant composition. CONCLUSION In this dataset of chemoprevention trial participants enrolled through the CPN consortium, highly favorable feedback was evident with respect to the overall study experience, suggesting that the recruitment and retention methods employed are facilitating success. These data can be used to help advance the NCI accrual quality improvement program in developing/enhancing strategies to improve accrual, retention, and adherence as well as enhance participant diversity in subsequent trials. Citation Format: David Zahrieh, Ryan P. McMurray, Nathan R. Foster, Paul J. Limburg, Sumithra J. Mandrekar. Participant satisfaction with cancer chemoprevention clinical trials: The Mayo Clinic Cancer Prevention Network (CPN) experience [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 5092.

PURPOSE The purpose of this study was to determine if dose de-escalation from 60 to 66 Gy to 30 to 36 Gy of adjuvant radiotherapy (RT) for selected patients with human papillomavirus–associated oropharyngeal squamous cell carcinoma could maintain historical rates for disease control while reducing toxicity and preserving swallow function and quality of life (QOL). PATIENTS AND METHODS MC1273 was a single-arm phase II trial testing an aggressive course of RT de-escalation after surgery. Eligibility criteria included patients with p16-positive oropharyngeal squamous cell carcinoma, smoking history of 10 pack-years or less, and negative margins. Cohort A (intermediate risk) received 30 Gy delivered in 1.5-Gy fractions twice per day over 2 weeks along with 15 mg/m 2 docetaxel once per week. Cohort B included patients with extranodal extension who received the same treatment plus a simultaneous integrated boost to nodal levels with extranodal extension to 36 Gy in 1.8-Gy fractions twice per day. The primary end point was locoregional tumor control at 2 years. Secondary end points included 2-year progression-free survival, overall survival, toxicity, swallow function, and patient-reported QOL. RESULTS Accrual was from September 2013 to June 2016 (N = 80; cohort A, n = 37; cohort B, n = 43). Median follow-up was 36 months, with a minimum follow-up of 25 months. The 2-year locoregional tumor control rate was 96.2%, with progression-free survival of 91.1% and overall survival of 98.7%. Rates of grade 3 or worse toxicity at pre-RT and 1 and 2 years post-RT were 2.5%, 0%, and 0%. Swallowing function improved slightly between pre-RT and 12 months post-RT, with one patient requiring temporary feeding tube placement. CONCLUSION Aggressive RT de-escalation resulted in locoregional tumor control rates comparable to historical controls, low toxicity, and little decrement in swallowing function or QOL.

6020 Background: A subset of salivary gland cancer (SGCs) express the androgen receptor (AR). This phase II trial evaluated the anti-androgen enzalumatide (Astellas) for patients with AR+ SGCs. Methods: Locally advanced/unresectable or metastatic AR+ SGCs were enrolled (AR status was centrally confirmed). Prior therapy with AR-targeted drugs was allowed. Enzalutamide 160 mg orally once daily was given (1 cycle= 28 days). The primary endpoint was confirmed response (RR) according to RECIST v1.1 within the first 8 cycles. Secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. A Simon-Optimal two-stage design was used to detect a 20% RR (vs. 5%) (alpha = 5%; beta = 90%). > 1 response(s) in the first 21 would trigger accrual to 41; > 4 responses would be considered promising. Results: 46 eligible patients (pts) were enrolled (40 M, 6 F; median age 65) in 22 months. In the first 21 pts, we initially had 2 confirmed PRs allowing for full study accrual, though one was later changed to stable disease. Among the 46 pts, 7 had PR as best response, though only 2 were confirmed within the first 8 cycles (4% (95% CI: 0.5-15%). Two other PRs did not count towards the primary endpoint due to 1) development beyond 8 cycles (cycles 12-18) and 2) a confirmatory scan completed <4 weeks apart. The other 3 pts with unconfirmed PR developed progression of disease (PD) after the first PR scan. 24 pts had stable disease; 15 pts PD as best response. Among 11 pts previously treated with AR-targeted therapy, best responses were 1 confirmed PR, 7 SD, 3 PD. With a median follow-up of 11.7 months (mo), OS at 12 mo was 66% (95% CI: 52-83%), PFS at 12 mo was 24% (95% CI: 14-42%), and median PFS was 5.5 mo (95% CI: 3.7-7.3). Conclusions: This is the first prospective trial evaluating an antiandrogen alone for AR+ SGCs. The failure to meet the protocol-defined measure of success was due in part to the lack of durability of initial responses. The clinical activity observed suggests the AR-dependence of AR+ SGCs, even among those previously treated with other hormonal therapies. Support: U10CA180821, U10CA180882; Astellas; https://acknowledgments.alliancefound.org. Clinical trial information: NCT02749903.