Citations

6592 Background: Sex, age and ECOG performance status (PS) may affect immune response and the efficacy of cancer immunotherapy with immune checkpoint inhibitors (ICI). We did a meta-analysis to assess the potential sex, age and ECOG PS differences of immunotherapy efficacy in advanced cancer. Methods: PubMed was searched up to January 15, 2019 for randomized controlled trials (RCT) comparing overall survival (OS) in patients with advanced cancer treated with ICI immunotherapy vs control therapy (without ICI). For sex difference analysis, pooled hazard ratio (HR) of death for men and women was calculated separately, and the heterogeneity between the two estimates was assessed using an interaction test by pooling study-specific interaction HR. Age ( < 65 vs ≥65) and ECOG PS (0 vs ≥1) difference was analyzed similarly. Subgroup analysis by cancer type and line of therapy (frontline vs subsequent) was explored. All analyses were done in Comprehensive Meta Analysis (v2) with random effects models. Results: Thirty phase 2/3 RCTs involving 17,728 patients were included. An OS benefit of immunotherapy was found for both men (HR 0.75, 95% confidence interval [CI] 0.69-0.81, P < 0.01) and women (HR 0.79, 95% CI 0.69-0.90, P < 0.01); for both younger ( < 65; HR 0.75, 95% CI 0.68-0.83, P < 0.01) and older (≥65; HR 0.76, 95% CI 0.69-0.83, P < 0.01) patients; and for both ECOG PS 0 (HR 0.78, 95% CI 0.69-0.89, P < 0.01) and PS ≥1 (HR 0.77, 95% CI 0.71-0.84, P < 0.01) patients. No significant difference of relative benefit from immunotherapy over control therapy was found in patients with different sex ( P = 0.283), age ( P = 0.906) or ECOG PS ( P = 0.783). In melanoma RCTs, compared with women (HR 0.77, 95% CI 0.64-0.94, P < 0.01), men (HR 0.56, 95% CI 0.42-0.76, P < 0.01) had more OS benefit from immunotherapy ( P = 0.037). No significant difference was found in other subgroup analyses by cancer types or line of therapy. Conclusions: Overall we found no evidence of association of sex, age, or ECOG PS with cancer immunotherapy efficacy. However, in melanoma, men might benefit more from immunotherapy than women.

1065 Background: Triple-negative breast cancer (TNBC) has been shown to display cyclin-dependent kinase 7 (CDK7)-dependent transcriptional addition and is sensitive to a CDK7 inhibitor THZ1. As tumor heterogeneity is well known, we sought to identify predictive markers of sensitivity to CDK7 inhibition in TNBC. Methods: Published mRNA microarray data was analyzed to identify genes associated with sensitivity of TNBC cells to the CDK7 inhibitor THZ1. Cell survival assay after THZ1 treatment was performed using Cell Counting Kit-8. Expression of SOX9 was examined by Western blot in cell lines and IHC in breast cancer tissue microarray. Patient survival analysis was done using the Kaplan-Meier method. Results: Analysis of published mRNA microarray data showed that SOX9 was overexpressed in the MDA-468 and BT-549 TNBC cell lines, which were sensitive to the CDK7 inhibitor THZ1 and showed decreased SOX9 expression with THZ1 treatment. We treated 10 TNBC cell lines with various concentrations of THZ1 and found that these cell lines displayed a wide spectrum of sensitivity to THZ1, with an IC50 ranging from 20-30 nM in sensitive lines (MDA-468 and MDA-231) to ~300 nM in insensitive lines (BT-20 and MDA-157). There was a strong correlation of SOX9 expression by Western blot and sensitivity to THZ1 in these cell lines (Pearson correlation, r = 0.82, P= 0.01). IHC of two tissue microarrays containing 278 breast cancer samples showed that SOX9 expression was significantly higher in TNBC (n = 59) compared to hormone positive breast cancer (n = 173; P< 0.01). Among the 59 TNBC cases, 43 had high SOX9 expression and 16 had low SOX9 expression. Patients with high or low SOX expression had similar grade, T stage and nodal involvement (All P> 0.20). Finally, with standard of care treatment, TNBC patients with high SOX9 expression had a significantly worse overall survival (OS) compared to patients with low SOX9 expression (2 year OS rate 100% vs 92.9%, 5 year OS rate 93.8% vs 83.3%, log rank P= 0.03). Conclusions: SOX9 expression level in TNBC cell lines was associated with sensitivity to the CDK7 inhibitor THZ1. TNBC patients with high expression of SOX9 had worse OS, and may benefit from CDK7 inhibition as a novel therapy.

e12073 Background: For T1-2N0M0 breast cancer after surgery and axillary staging, the current NCCN guideline recommends radiation therapy (RT) after lumpectomy but not total mastectomy unless there is a positive or less than 1 mm negative margin. This recommendation is regardless of hormonal status. Triple-negative breast cancer is a generally considered more aggressive compared with hormone positive breast cancer. We sought to investigate whether there is a survival benefit of RT in T1-2N0M0 TNBC. Methods: A Population-based retrospective analysis was performed using the Surveillance, Epidemiology, and End Results (SEER) database. Patients included in the analysis were divided into three groups according to surgery modality and RT: breast conservation therapy (BCT, i.e., lumpectomy + RT), mastectomy alone, and mastectomy + RT. The survival endpoints were breast cancer-specific survival (BCSS) and overall survival (OS), and survival analysis was performed using the Kaplan-Meier method. Results: A total of 22473 female with T1-2N0M0 TNBC diagnosed between 2010 and 2015 were included, with 13395 (60%) T1 and 9078 (40%) T2 cases. Surgery, RT and chemotherapy was done in 21674 (96%), 9633 (43%) and 14651 (65%) patients, respectively. Patients who underwent RT were older ( > 50 years, 78% vs 72%, P< 0.001), had fewer T2 (35% vs 44%, P< 0.001) tumor, and had more chemotherapy utilization (72% vs 60%, P< 0.001). 8807 patients had BCT; 8329 had mastectomy alone and 635 had mastectomy + RT. The 5-year BCSS rate was 94.3% for BCT, 93.3% for mastectomy alone ( P= 0.009 vs BCT), and 83.7% for mastectomy + RT ( P< 0.001 vs BCT and P< 0.001 vs mastectomy alone), respectively. The 5-year OS rate was 88.6% for BCT, 83.0 % for mastectomy alone ( P< 0.001 vs BCT), and 79.6% for mastectomy + RT ( P< 0.001 vs BCT and P= 0.190 vs mastectomy alone), respectively. Conclusions: In patients with T1-2N0M0 TNBC, BCT was associated with superior BCSS and OS compared to mastectomy with or without RT. After mastectomy, there was no evidence of survival benefit of RT, with worse BCSS and similar OS.

Abstract Background: Multiple myeloma (MM) accounts for approximately 1% of all cancers and 10% of hematologic malignancies in the United States (U.S.). MM occurs in all races, but the incidence in African Americans is two to three times higher than in non-Hispanic whites. MM is also slightly more frequent in men than women (1.4:1). Many clinical trials lack appropriate representation of specific patient populations, limiting the generalizability of the evidence obtained. Therefore, we determined the representation of ethnic minorities, the elderly, and women in MM clinical trials. Methods: Enrollment data from all therapeutic trials reported as completed in clinicaltrial.gov from 2000 to 2016 were analyzed. Clinical trials including other hematologic malignancies and with recruitment outside of the U.S. were excluded. Enrollment fraction (EF) was defined as the number of enrollees divided by the 2013 SEER database MM complete prevalence. Chi-square test was used to estimate differences in categorical data. Results: Out of 177 MM clinical trials (CT), 78 (44%) reported ethnicity with a total of 12,055 enrollees. Regarding enrollees' ethnic composition, 84% were non-Hispanic White (NHW), 8.6% African American (AA), 2.8% Asian, 1.8% Hispanic, and 0.1% Native American/Alaskan Indian. Out of those 78 CT, 52 (66%) were phase II, 15 (19%) phase III, and 11 (14%) phase I. Most of the results were published from 2012 to 2016 (74%). Forty-six (59%) trials were sponsored by industry, 7 (9%) by NCI, and 25 (32%) were investigator initiated. Participation in CT varied significantly across ethnic groups, NHW were more likely to be enrolled in CT (EF of 0.23) than AA (EF of 0.08, p &lt; 0.0001) and Hispanics (EF of 0.05, p&lt; 0.0001). Males had a higher recruitment rate than females (58% vs. 42%), but this could be explained by the higher incidence of MM in males. Enrollees' median age was 62 years. Younger patients (&lt; 65 years) were more likely to be enrolled in CT than the elderly (66% vs. 34%, p&lt;0.0001). Industry-sponsored trials were less likely to recruit AA compared with investigator-initiated trials (7.6% vs. 12%, p&lt;0.01). Conclusions: Despite the higher incidence of MM in African Americans and the elderly, the former only represented 8.6% of the study participants and 66% of these were less than 65 years of age; therefore, we are lacking data in the tolerability of these new agents in our aging MM population. We also observed that industry studies were less likely to recruit AA patients. Collaborations between investigators, sponsors, and the community are necessary to increase our minority and elderly patients' access to clinical trials. Citation Format: Narjust Duma, Miguel Gonzalez Velez, Jesus Vera-Aguilera, Richardo Parrondo, Veronica Mariotti, Jonas Paludo, Yucai Wang, Ronald Go, Alex Adjei. Diversity in multiple myeloma clinical trials [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A27.

Abstract Background: Despite the importance of diversity while studying new drugs, many cancer clinical trials (CT) lack appropriate representation of specific patient populations, limiting the generalizability of the evidence obtained. Therefore, we determined the representation of ethnic minorities, the elderly, and women in cancer CT. Methods: Enrollment data from all therapeutic trials reported as completed in clinicaltrial.gov from 2003 to 2016 were analyzed. CT in rare cancers (&lt; 1% incidence) or with recruitment outside of the United States were excluded. Enrollment fraction (EF) was defined as the number of enrollees divided by the 2013 Surveillance Epidemiology and End Results (SEER) database cancer prevalence. Results: Out of 1,012 CT, 310 (31%) reported ethnicity with a total of 55,689 enrollees. 46,431 (83%) enrollees were non-Hispanic white, 3,270 (6%) African American, 2,982 (5.3%) Asian, 1,484 (2.6%) Hispanic, and 1,332 (2.4%) were classified as other. Participation in CT varied significantly across ethnic groups; non-Hispanic whites were more likely to be enrolled in CT (EF of 1.2%) than African Americans (EF of 0.7%, p &lt;0.001) and Hispanics (EF of 0.4%, p &lt;0.001). A decrease in African American (6% vs. 9.2%) and Hispanic (2.6% vs. 3.1%) enrollment was observed when compared with historical data from 1996 to 2002. Asians were well represented and their recruitment doubled over the past 14 years (2% vs. 5.3%). Hispanics were less represented in breast and prostate cancer CT, only contributing to 3% and 1.5% of the study population. African Americans were less represented in lung (5.4%) and renal cell carcinoma (3%) trials. Enrollees' median age was 60 years with 64% of patients &lt;65 years of age. Younger patients (&lt;65 years) were more likely to be enrolled in CT than the elderly (64% vs. 36%, p &lt; 0.001). Lower recruitment of female patients was observed in CT for melanoma (35%), lung (39%), and pancreatic cancer (40%). Conclusions: African Americans, Hispanics, and the elderly were less likely to be enrolled in CT. Comparing with historical data, we observed a decrease in minorities' recruitment over the past 14 years. This change could be attributed to the increased complexity of CT and mandatory molecular testing as many minorities lack access to institutions with genetic-testing capacity. Future trials should take extra measures to recruit participants who adequately represent the U.S. cancer population. Citation Format: Narjust Duma, Jesus Vera-Aguilera, Yucai Wang, Jonas Paludo, Konstantinos Leventakos, Aaron Mansfield, Alex Adjei. Representation of minorities, the elderly, and women in over 1000 clinical trials [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A26.

8034 Background: Multiple myeloma (MM), a monoclonal plasma cell disorder, is one of the most common hematologic malignancies in the US. In preclinical studies, metformin demonstrated plasma cells cytotoxicity. However, there is lack of studies translating the effect of metformin into the clinical setting. Therefore, we assessed the clinical effect of metformin in patients (pts) with MM. Methods: All MM pts who underwent stem cell transplant (SCT) at the Mayo Clinic Rochester from 2007 to 2012 were reviewed. Patients were grouped based on metformin use. Initial diagnosis at our institution and ≥12 months of follow up were required. Kaplan-Meier method and Cox regression were used for time-to-event and multivariate analysis. Results: Out of 687 pts, 78 (11.4%) were using metformin at the time of MM diagnosis. Baseline characteristics in the metformin (Mt) and no-metformin (NMt) groups were similar (Table). Median (M) metformin dose was 2000 mg daily and m duration of metformin use from MM diagnosis was 22 months. Pts on the Mt group achieved higher rates of CR after SCT (41% vs. 29%, p<0.02). Median PFS after SCT was longer in the Mt group, 31.3 months (95% CI: 10.4-52.2) vs. 16.6 months in the NMt group (95%CI: 14.5-18.7) p<0.04. There was a trend towards longer OS in the Mt group, but it was not statistically significant (170 vs. 106 months, p<0.10). In a multivariate analysis of metformin use, age, ISS, LDH, and cytogenetics/FISH, the former was an independent predictor of PFS after SCT (OR: 0.38, 95%CI: 0.20-0.68, p<0.001). Conclusions: Metformin use was associated with a better PFS and higher CR after SCT in our MM cohort. A trend towards better OS was also noted in the Mt group. Larger studies are needed to enhance our understanding of the clinic effect of metformin on MM. [Table: see text]

2533 Background: Many cancer clinical trials (CT) lack appropriate representation of specific patients populations, limiting the generalizability of the evidence obtained. Therefore, we determined the representation of ethnic minorities in oncology CT. Methods: Enrollment data from all therapeutic trials reported as completed in clinicaltrial.gov from 2003 to 2016 were analyzed. CT in rare cancers (< 1% incidence) or with recruitment outside of the US were excluded. Enrollment fraction (EF) was defined as the number of enrollees divided by the 2013 SEER database cancer prevalence. Chi-square test was used to estimate differences in categorical data. Results: Out of 1,012 CT, 310 (31%) reported ethnicity with a total of 55689 enrollees. Distribution by race and comparison with data from 1996-2002, US cancer prevalence and US census are described in the Table. Participation in CT varied significantly across ethnic groups, non-Hispanic Whites (NHW) were more likely to be enrolled in CT (EF of 1.2%) than African Americans (EF of 0.7%, p < 0.001) and Hispanics (EF of 0.4%, p<0.001). A decrease in African Americans (AA) and Hispanics (H) enrollment was observed when compared with historical data from 1996 to 2002. Hispanics were less represented in breast and prostate cancer CT contributing only to 3% and 1.5% of the study population; African Americans were less represented in lung (5.4%) and renal cell carcinoma (3%) trials. Asians were well represented and their recruitment doubled over the past 14 years (2% vs 5.3%). Conclusions: African Americans and Hispanics were less likely to be enrolled in CT. Comparing with historical data; we observed a decrease in minorities’ recruitment in the past 14 years. This change could be attributed to the increased complexity of CT and mandatory molecular testing as many minorities lack access to institutions with genetic testing capacity. Future trials should take extra measures to recruit participants that adequately represent the U.S. cancer population. [Table: see text]