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TPS208 Background: Castrate resistant prostate cancer (CRPC) is an immunologically cold tumor, with a 5% response rate reported to the PD-L1 inhibitor pembrolizumab. VEGF secreted by tumors may play a key role in hindering the anti-tumor immune response, leading to the development of an abnormal vasculature that may limit immune surveillance. VEGF also inhibits dendritic cell differentiation, limiting the presentation of tumor antigens. The inhibition of VEGF may therefore potentiate the effect of PD-1/L1 directed therapy by enabling immune surveillance and antigen presentation. VEGF-TKI and checkpoint inhibitor combinations are currently approved in the treatment of advanced kidney, cervical, and endometrial cancers. This signal-seeking study aims to determine whether the combination of the VEGF-TKI tivozanib and the PD-L1 inhibitor atezolizumab may be effective in CRPC and certain other immunologically cold tumors. Methods: The trial is a single center phase Ib/II basket study in multiple immunologically cold tumors. Co-primary endpoints are safety and the overall response rate as measured via RECIST v1.1. The tivozanib dose will be determined via a 3+3 dose de-escalation phase Ib portion. Patients treated in the phase Ib portion will be included as study subjects for phase the II portion. The study is designed to test for a 25%+ response rate as compared to a null hypothesis of

TPS280 Background: Patients with advanced colorectal cancer after progressing through first line therapy, have several FDA-approved systemic therapies that are associated with clinical benefit for a substantive minority of patients. Current clinical practice is to trial these various treatments in a step-wise fashion using CT scans every 3 months to evaluate effectiveness. This process requires 3-4 months between therapeutic interventions from which the patient may ultimately derive no clinical benefit, may have a performance status decline; limiting the number of possible interventions and increases risk for physical and financial toxicity. An alternative to the traditional CT-scan guided approach for disease assessment is a circulating tumor DNA (ctDNA) intervention. The Signatera ctDNA assay which utilizes 16 truncal mutations derived from a patient’s tumor, can be assessed every 2 weeks for a rapid determination of the effectiveness of a systemic therapy. This may allow patients to be exposed to many treatments during a short time, limiting toxicity, allowing for a quicker determination of clinical benefit and personalization of treatment. The aim of this study will be to compare the traditional scan-driven approach vs an intervention guided by ctDNA assessments, both arms using a pre-specified order of chemotherapy treatments. Methods: This is a phase 2 randomized study of patients with refractory metastatic adenocarcinoma of the colon or rectum. Participants are eligible after progression or intolerance to first line chemotherapy or recurrence within 6 months of adjuvant oxaliplatin based chemotherapy. They must have RECIST measurable metastatic disease that is not eligible for definitive management. Tissue from the primary and/or metastatic deposit is required for Signatera NGS analysis and subjects must have measurable ctDNA at sampling. Participants must be ≥18 years old without major organ dysfunction and have an ECOG performance status of 0 to 2. Subjects with Microsatellite High, deficient in DNA mismatch repair genes, or BRAF V600E mutations are excluded. Subjects will be randomized 1:1 to Arm A (ctDNA guided intervention) or Arm B (scan-guided control group). Patients in both arms will undergo systemic treatments in a standardized pre-specified order. Arm A will have ctDNA assessments every 2 weeks until an intervention shows a significant decrease, then every 4 weeks until Progressive Disease (PD) by scan or significant ctDNA increase. CT imaging will be performed every 12 weeks. Those in Arm B, will have CT imaging every 12 weeks and blood collected for post-hoc analysis every 4 weeks until PD by scan. The primary endpoint is overall survival. Secondary endpoints include progression free survival and overall response. Exploratory analysis with be performed of the microbiome. Enrollment continues to a maximum of 78 patients. Clinical trial information: NCT04786600 .

12129 Background: Depression, anxiety, and fear of cancer recurrence (FCR) constitute prevalent psychological concerns necessitating further attention in developing supportive care interventions for women with gynecologic, gastrointestinal, and thoracic cancers. Recent evidence indicates that such concerns may be especially severe among underserved women of color and women affected by low-socioeconomic status (SES). The purpose of the present study is to evaluate the magnitude of changes in depression, anxiety, and FCR associated with a mindfulness-based yoga intervention among a diverse sample of women with these cancers. A second aim is to identify how changes in these concerns may differ across sociodemographic groups. Methods: Women with gynecologic ( n=86), gastrointestinal ( n=17), or thoracic ( n=20) cancers were enrolled in a group-based 10-week yoga intervention utilizing mindfulness meditation, relaxation, and gentle yoga. Prior to and following intervention, participants were administered assessments, including the Beck Depression Inventory – Second Edition (BDI-II) to measure depression, the State-Trait Anxiety Inventory (STAI) to assess anxiety, and the Fear of Cancer Recurrence Inventory (FCRI) to evaluate aspects of FCR. Mixed-linear models evaluated change in outcomes from pre- to post-intervention, with conditional models assessing the effects of age, race/ethnicity, and SES on change. Analyses were conducted prior to trial completion due to approaching accrual period termination. Results: The sample demonstrated a mean age of 58.46 ( SD=10.82) and mean SES score of 3.98 ( SD=1.55) using a 1 to 7 composite scale. Twenty-six percent of participants were of racial and/or ethnic minority status ( n=32). Significant declines in total depressive symptoms, somatic depressive symptoms, state anxiety, and psychological distress due to FCR were observed across the sample. Higher SES was associated with significantly greater reductions in total depressive symptoms and affective depressive symptoms, specifically. Women of color experienced significantly greater declines in somatic symptoms compared to non-Hispanic White women. Conclusions: This mindfulness-based yoga intervention was associated with significant reductions in depressive symptoms, state anxiety, and psychological distress related to FCR among women with gynecologic, gastrointestinal, and thoracic cancers. Higher SES and underserved race/ethnicity status moderated some of these effects. Future research should explore the efficacy of this intervention among diverse women in a randomized clinical trial context. Clinical trial information: NCT03385577.

3122 Background: BRCA1-Associated Protein 1 (BAP1) acts as a tumor suppressor and critical regulator of the cell cycle and DNA damage response (DDR). PARP inhibitors (PARPi) demonstrate synthetic lethality in BAP1 mutant (mBAP1) preclinical models, independent of underlying germline BRCA status. mBAP1 leads to a loss of functional protein in several solid tumors. This study aimed to explore the clinical activity of niraparib in patients (pts) with advanced tumors likely to harbor mBAP1. Methods: Eligible adult pts with measurable metastatic solid tumors having exhausted approved therapies, adequate organ function, and ECOG PS 0-1 were assigned to Cohort A (histology-specific): tumors likely to harbor mBAP1 (i.e., cholangiocarcinoma, uveal melanoma, mesothelioma, or clear cell renal cell carcinoma) with tissue available for mBAP1 confirmation; or Cohort B (histology-agnostic): tumors with other known non-BRCA confirmed DDR mutations. Known BRCA1 or 2 mutations or prior PARPi exposure were excluded. All pts received niraparib 200-300mg daily, depending on weight and/or platelet count. Radiographic response was assessed by RECIST v1.1 measured every 8 weeks while on treatment. The primary endpoint was ORR with secondary endpoints of PFS, OS, clinical benefit (CR+PR+SD), toxicity, and exploratory biomarker determinations. Cohort A employed Simon's optimal two-stage design to assess a 30% ORR increase (a = 0.05; power = 90%). Cohort B aimed to assess a 40% ORR increase for this molecularly selected/enriched patient population. Results: From 08/13/2018 to 12/21/2021, 37 pts enrolled from two different centers, with 32 evaluable for response (Cohort A n = 18; Cohort B n = 14). In Cohort A, best ORR was 1 PR (6%), 8 SD (44%; median 5.7 mo; range 2 - 9.4 mo), and 9 PD (50%). Cohort A was stopped at the first stage following the pre-specified Simon’s design. mBAP1 was confirmed in 7/9 pts (78%) with PR or SD but in only 2/9 (22%) in those with PD. In Cohort B, best ORR was 6 SD (43%; median 7.5 mo; range 3.3 - 8.6 mo) and 8 PD (57%). Mutations in those with SD included ATM, CHEK2, PTEN, RAD50, and ARID1A. Common grade 3/4 AEs observed were anemia (16%), thrombocytopenia (16%), nausea (11%), and vomiting (8%). There were no unexpected nor grade 5 toxicities. Conclusions: The use of niraparib was well tolerated in pts with advanced treatment refractory solid tumors but failed to meet pre-specified efficacy threshold of ORR. However, clinical benefit was identified in 78% of patients in cohort A who had a confirmed mBAP1 tumor. Further correlative analyses are ongoing and additional clinical development restricted to mBAP1 tumors may be justified. Clinical trial information: NCT03207347.

e24125 Background: Gynecologic, gastrointestinal (GI), and thoracic cancers account for significant morbidity and mortality in the U.S. Women with these types of cancers frequently experience psychological distress, among other poor outcomes. Previous research has indicated that mindfulness-based interventions, such as yoga, can be effective in decreasing distress in cancer patients. Notably, this research has primarily been conducted in a breast cancer population with limited research assessing the feasibility, acceptability, and/or efficacy of this type of intervention in other prevalent and impactful cancers among women. The purpose of the present study was to assess the Feasibility and Acceptability of a yoga intervention for women with gynecologic, GI, or thoracic cancers. Methods: A total of 124 women diagnosed with a gynecologic, GI, or thoracic cancer in the prior year were recruited via outpatient oncology clinics to participate in a 10-week, group-based manualized yoga intervention entitled “Stilling the Waters of Uncertainty” (Author: E. Kacel) that is nearing the end of accrual. Participants completed an Acceptability evaluation following each yoga session with ratings on a 5-point Likert scale from “not at all” to “extremely.” Feasibility of the study was operationalized as percentage of eligible participants who (a) enrolled, (b) attended sessions, and (c) completed post-intervention assessment. Acceptability was operationalized as the percentage of participants with average session ratings of “very” or “extremely” for intervention usefulness, enjoyableness, safety, clarity, relevance, and likelihood of continuing to practice skills. Criteria for operationalizing Feasibility and Acceptability for this study were defined a priori based on recommendations of Bowen and colleagues (2009). A minimum of 80% for each measure of feasibility and acceptability was set as the a priori threshold of success in each domain. Results: All measures of Feasibility were below the a priori benchmark of 80%: Of the 318 eligible patients approached for participation, (a) 124 patients (39.0%) enrolled; 49/124 (39.5%) attended at least 1 yoga session; 44/124 (35.4%) attended at least 8 sessions; and (c) 41/124 (33.1%) completed post-intervention assessment procedures. At least 80% of attendees rated the intervention as “very” or “extremely” useful, enjoyable, safe, and clear; 75.5% and 79.6% of attendees rated the intervention as “very” or “extremely” relevant and likely to be continued to be practiced. Conclusions: The results of this study indicate that a yoga intervention for women with prevalent non-breast cancer types did not meet a priori criteria for feasibility. However, participants who attended at least 1 session rated the intervention as generally acceptable. Future research is needed to improve study/intervention feasibility in this population. Clinical trial information: NCT03385577.

PURPOSE: Some elderly patients (≥ 65 years old) with small-cell lung cancer (SCLC) do not receive chemotherapy likely because of fear of toxicity and uncertainty regarding benefits. Thus, we aimed to study real-world trends in utilization of antineoplastics over the years and predictors of utilization, survival, and Medicare expenditure in elderly patients with extensive-stage (ES) SCLC. PATIENTS AND METHODS: Using the linked SEER and Medicare database, we identified elderly patients with newly diagnosed ES-SCLC between 2001 and 2013. The Wald test was used to determine the significance of trends. Cox proportional hazards models were applied for survival analyses. We used SAS, version 9.4 (SAS Institute, Cary, NC). RESULTS: We identified 15,763 patients with newly diagnosed ES-SCLC. Approximately 6,838 patients (43.38%) received antineoplastics, and 8,925 patients (56.61%) received supportive care only. Every year since 2001, the percentage of patients receiving antineoplastics has decreased (45.8% v 36.6% in 2001 and 2013, respectively; Ptrend < .0001). Patients with advanced age ( P < .001), patients from high-poverty areas ( P < .001) or rural areas ( P = .005), patients with Charlson comorbidity index ≥ 3 ( P < .001), and non-Hispanic blacks ( P = .003) and Hispanics ( P = .001) were less likely to receive antineoplastics. Mean Medicare spending per patient decreased over the study period for patients treated with antineoplastics ($45,998 in 2001 and $35,053 in 2013; Ptrend < .001) and for those receiving supportive care only ($34,197 in 2001 and $25,265 in 2013; Ptrend < .001). CONCLUSION: Decreasing utilization of antineoplastics in elderly patients with ES-SCLC since 2001 could be partly secondary to higher comorbidities and physiologic age, leading to poor candidacy. Medicare expenditures decreased likely as a result of value-based treatment initiatives by the Centers for Medicaid and Medicare Services. However, expenditures are likely to increase with use of expensive novel agents.

TPS223 Background: Patients with advanced colorectal cancer after progressing through first line therapy, have several FDA-approved systemic therapies that are associated with clinical benefit for a substantive minority of patients. Current clinical practice is to trial these various treatments in a step-wise fashion using CT scans every 3 months to evaluate effectiveness. This process requires 3-4 months between therapeutic interventions from which the patient may ultimately derive no clinical benefit, may have a performance status decline; limiting the number of possible interventions and increases risk for physical and financial toxicity. An alternative to the traditional CT-scan guided approach for disease assessment is a circulating tumor DNA (ctDNA) intervention. The Signatera ctDNA assay which utilizes 16 truncal mutations derived from a patient’s tumor, can be assessed every 2 weeks for a rapid determination of the effectiveness of a systemic therapy. This may allow patients to be exposed to many treatments during a short time, limiting toxicity, allowing for a quicker determination of clinical benefit and personalization of treatment. The aim of this study will be to compare the traditional scan-driven approach vs an intervention guided by ctDNA assessments, both arms using a pre-specified order of chemotherapy treatments. Methods: This is a phase 2 randomized study of patients with refractory metastatic adenocarcinoma of the colon or rectum. Participants are eligible after progression or intolerance to first line chemotherapy or recurrence within 6 months of adjuvant oxaliplatin based chemotherapy. They must have RECIST measurable metastatic disease that is not eligible for definitive management. Tissue from the primary and/or metastatic deposit is required for Signatera NGS analysis and subjects must have measurable ctDNA at sampling. Participants must be ≥18 years old without major organ dysfunction and have an ECOG performance status of 0 to 2. Subjects with Microsatellite High, deficient in DNA mismatch repair genes, or BRAF V600E mutations are excluded. Subjects will be randomized 1:1 to Arm A (ctDNA guided intervention) or Arm B (scan-guided control group). Patients in both arms will undergo systemic treatments in a standardized pre-specified order. Arm A will have ctDNA assessments every 2 weeks until an intervention shows a significant decrease, then every 4 weeks until Progressive Disease (PD) by scan or significant ctDNA increase. CT imaging will be performed every 12 weeks. Those in Arm B, will have CT imaging every 12 weeks and blood collected for post-hoc analysis every 4 weeks until PD by scan. The primary endpoint is overall survival. Secondary endpoints include progression free survival and overall response. Exploratory analysis with be performed of the microbiome. Enrollment continues to a maximum of 78 patients. Clinical trial information: NCT04786600.

TPS354 Background: BRCA1-Associated Protein 1 (BAP1) is a critical regulator of the cell cycle, cellular differentiation, cell death, and DNA damage response. It also acts as a tumor suppressor. Preclinical models demonstrate significant synthetic lethality in BAP1 mutant cell lines and patient xenografts when treated with PARP inhibitors, independent of underlying BRCA status, suggesting this mutation confers a BRCA-like phenotype. BAP1 is mutated, leading to a loss of functional protein, in up to 30% of cholangiocarcinomas as well as several other solid tumors. Methods: This phase 2, open-label, single arm multicenter study aims to exploit the concept of synthetic lethality with the use of the PARP inhibitor niraparib in pts with metastatic relapsed or refractory solid tumors. Eligible pts with measurable metastatic and incurable solid tumors are assigned to one of two cohorts: Cohort A (histology-specific): tumors harboring suspected BAP1 mutations including cholangiocarcinoma, uveal melanoma, mesothelioma or clear cell renal cell carcinoma with tissue available for BAP1 mutational assessment via NGS or Cohort B (histology-agnostic): tumors with known DNA damage response (DDR) mutations (Table) confirmed by CLIA-approved NGS. Other key eligibility criteria include age ≥18 years, adequate cardiac, renal, hepatic function and Eastern Cooperative Oncology Group performance status of 0 to 1. Pts with known BRCA1 or BRCA2 mutations or prior PARPi exposure are excluded. Pts receive niraparib 200-300mg daily (depending on weight and/or platelet count) continuously. Primary endpoint is objective response rate with secondary endpoints of PFS, OS, toxicity and exploratory biomarker determinations. Radiographic response by RECIST criteria is measured every 8 weeks while on treatment. Cohort A has fully enrolled. Cohort B enrollment continues to a maximum of 47 total evaluable subjects with expansion cohorts allowable for histologic or molecular subtypes meeting pre-specified responses. NCT03207347 Clinical trial information: NCT03207347. [Table: see text]

e22061 Background: BRCA-associated protein-1 (BAP1) is a ubiquitin ligase associated with regulating cell cycle, cell proliferation, DNA damage pathway, and cell death. It also acts as a tumor suppressor gene as seen in hereditary cancer syndrome associated with germline mutations in BAP1. Preclinical studies have shown that PARP-inhibitor treatment of BAP1 mutant cell lines demonstrated significant synthetic lethality, independent of underlying BRCA status suggesting this mutation confers a BRCA-like phenotype. BAP1 is mutated, leading to a loss of functional protein, in up to 30% of several solid tumors including cholangiocarcinoma, mesothelioma, uveal melanoma, and clear cell renal cell carcinoma. Methods: This phase 2, open-label, single arm study aims to exploit the concept of synthetic lethality with the use of the PARP inhibitor niraparib in two biologically distinct cohorts. Eligible patients (pts) with measurable metastatic and incurable solid tumors are assigned to one of the two cohorts: Cohort A (histology-specific): tumors harboring suspected BAP1 mutations including cholangiocarcinoma, uveal melanoma, mesothelioma or clear cell renal cell carcinoma with tissue available for BAP1 mutational assessment via Next Generation Sequencing (NGS); or Cohort B (histology-agnostic): tumors with known DNA damage response (DDR) mutations (Table) confirmed by CLIA-approved NGS. Key inclusion criteria also include age ≥18 years, adequate cardiac, renal, hepatic function and ECOG PS of 0 to 1. Key exclusion criteria include known BRCA1 or BRCA2 mutations or prior PARPi exposure. Pts receive niraparib 200-300mg daily (depending on weight and/or platelet count) continuously. Primary endpoint is objective response rate (ORR), and secondary endpoints are progression free survival (PFS), overall survival (OS), toxicity and exploratory biomarker determinations. Radiographic response by RECIST criteria is measured every 8 weeks while on treatment. Cohort B enrollment is closed. Enrollment in Cohort A continues. A maximum of 47 evaluable subjects is planned with expansion cohorts allowable for histologic or molecular subtypes meeting pre-specified responses. Clinical trial information: NCT03207347. [Table: see text]

Defects in DNA repair can result in oncogenic genomic instability. Cancers occurring from DNA repair defects were once thought to be limited to rare inherited mutations (such as BRCA1 or 2). It now appears that a clinically significant fraction of cancers have acquired DNA repair defects. DNA repair pathways operate in related networks, and cancers arising from loss of one DNA repair component typically become addicted to other repair pathways to survive and proliferate. Drug inhibition of the rescue repair pathway prevents the repair-deficient cancer cell from replicating, causing apoptosis (termed synthetic lethality). However, the selective pressure of inhibiting the rescue repair pathway can generate further mutations that confer resistance to the synthetic lethal drugs. Many such drugs currently in clinical use inhibit PARP1, a repair component to which cancers arising from inherited BRCA1 or 2 mutations become addicted. It is now clear that drugs inducing synthetic lethality may also be therapeutic in cancers with acquired DNA repair defects, which would markedly broaden their applicability beyond treatment of cancers with inherited DNA repair defects. Here we review how each DNA repair pathway can be attacked therapeutically and evaluate DNA repair components as potential drug targets to induce synthetic lethality. Clinical use of drugs targeting DNA repair will markedly increase when functional and genetic loss of repair components are consistently identified. In addition, future therapies will exploit artificial synthetic lethality, where complementary DNA repair pathways are targeted simultaneously in cancers without DNA repair defects.

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Cigarette smoking is a major risk factor for all types of lung cancers. Nicotine, the addictive component of cigarettes, accelerates the growth and angiogenesis of human lung cancers. The biological activity of nicotine is mediated by nicotinic acetylcholine receptors (nAChRs). The endogenous ligand of nAChRs is acetylcholine (ACh). We show that both human SCLCs and NSCLCs contain all proteins of the acetylcholine signaling pathway, namely nAChRs, choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), choline transporter (ChT1) and acetylcholinesterase (AChE). ACh functions as an autocrine growth factor for human lung cancer cells. Lung adenocarcinoma (LAC), squamous cell carcinoma (SCC-L) and invasive mucinous adenocarcinoma (IMA) express a diverse array of nAChRs. In addition, normal human lung cells also express nAChRs and other ACh signaling proteins. Nicotine amplifies the ACh signaling loop in human lung cancer cells. It increases the levels of alpha7-nAChR subunit in human SCC-Ls. The alpha7-nAChR is responsible for the proliferative and pro-angiogenic activity of nicotine in lung cancer. The level of alpha7-nAChR was analyzed in human SCC-L samples isolated from patients. It was found that the level of alpha7-nAChR in SCC-L patients (who are heavy smokers) was much higher than that of moderate smoker suffering from SCC-Ls. Nicotine was also found to elevate the levels of ChAT and VAChT in human lung cancers. The acetylcholine signaling pathway may be a useful molecular target for the diagnosis and therapy of human lung cancers in smokers. Our results are also relevant to lung cancer patients who are exposed to nicotine via secondhand smoke, nicotine patches, gums or electronic cigarettes. Citation Format: Kathleen C. Brown, Jamie K. Lau, Haley E. Perry, Brent A. Thornhill, Cathryn D. Stevenson, William D. Rollyson, Cody A. Stover, Dennie V. Jones, Joseph F. Pulliam, Piyali Dasgupta. The acetylcholine signaling pathway: A novel molecular target for lung cancers. [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 1032. doi:10.1158/1538-7445.AM2015-1032