Aguilera, Jesus Vera

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]

Abstract Lessons Learned Everolimus does not have sufficient activity to justify its use as single agent in metastatic melanoma. Patients treated with 10 mg per day dose were most likely to require dose reductions. Everolimus appeared to reduce the numbers of regulatory T cells in approximately half of the treated patients; unfortunately, these effects were not correlated with clinical outcomes. Background Everolimus (RAD-001) is an orally active rapamycin analogue shown in preclinical data to produce cytostatic cell inhibition, which may be potentially beneficial in treating melanoma. We conducted a phase II study to evaluate the efficacy and safety of everolimus in patients with unresectable metastatic melanoma (MM). Methods This study included two cohorts; cohort 1 received 30 mg of everolimus by mouth (PO) weekly, and cohort 2 was dosed with 10 mg of everolimus PO daily. The endpoints of the study were safety, 16-week progression-free survival (PFS), overall survival (OS), and measures of immunomodulatory/antiangiogenic properties with therapy. Tumor samples before therapy and at week 8 of treatment were analyzed. Peripheral blood plasma or mononuclear cell isolates collected prior to therapy and at weeks 8 and 16 and at time of tumor progression were analyzed for vascular endothelial growth factor and regulatory T-cell (Treg) measurements. Results A total of 53 patients were enrolled in cohort 1 (n = 24) and cohort 2 (n = 29). Only 2 patients of the first 20 patients enrolled in cohort 2 had treatment responses (25%; 95% confidence interval, 8.6%–49.1%); this result did not allow full accrual to cohort 2, as the study was terminated for futility. Median OS was 12.2 months for cohort 1 versus 8.1 months in cohort 2; no PFS advantage was seen in either group (2.1 months vs. 1.8 months). Dose-limiting toxicities included grade 4 myocardial ischemia (3.4%); grade 3 fatigue, mucositis, and hyperglycemia (10.3%); and anorexia and anemia (6.9%). Everolimus significantly reduced the number of Tregs in approximately half of the treated patients; however, these effects were not correlated with clinical outcomes. Conclusion Everolimus does not have sufficient single-agent activity in MM; however, we have identified evidence of biological activity to provide a potential rationale for future combination studies.

186 Background: The optimal sequence strategy of BRAF/MEK inhibitors, anti-PD- 1/PDL-1 and anti-CTLA-4 in metastatic BRAF-mutated melanoma patients (pts) is unknown and no treatment guidelines exist. Therefore, we report a single-institution experience of different treatment approaches using targeted therapy (TT) and immunotherapy and its impact on outcomes. Methods: BRAF-mutated metastatic melanoma pts treated with TT and immunotherapy from 2012 to2017 were analyzed. Six groups were identified based on treatment strategy. All time-to-event analyses were calculated using the Kaplan-Meier method and Wilcoxon test. Results: Forty-four pts were identified. The median age at diagnosis was 49 years (range 21-73), 54% pts were females and 43% developed brain metastases during disease course. The most common approach strategy was immunotherapy followed by TT, the median duration of treatment was 11 and 19 weeks, respectively. Time-to-next therapy (TTNT) following 1st line treatment was similar in pts treated with TT (median 23 weeks [95% CI: 15-31]) or immunotherapy (median 26 weeks [95% CI: 10-33], p = 0.94). A trend towards better overall survival (OS) was seen in pts who received immunotherapy followed by TT (p = 0.09); patients who received salvage chemotherapy (carboplatin/paclitaxel) had significantly longer OS (median 7 years [95% CI: 3.2-7.08]) ( p = 0.03). Conclusions: No differences in TTNT were seen with immunotherapy, TT or combined (triple therapy) when used as 1st or 2nd line. The significant longer OS benefit with 1st line immunotherapy was only seen in patients who received chemotherapy later in their treatment course. [Table: see text]

Purpose: Many cancer clinical trials lack appropriate representation of specific patient populations, limiting their generalizability. Therefore, we determined the representation of ethnic minorities and women in cancer clinical trials. Methods: Enrollment data from all therapeutic trials reported as completed in ClinicalTrials.gov from 2003 to 2016 were analyzed. We calculated enrollment fractions (EFs) for each group, defined as the number of enrollees divided by the 2013 Surveillance, Epidemiology, and End Results (SEER) database cancer prevalence. Results: Of 1,012 clinical trials, 310 (31%) reported ethnicity with a total of 55,689 enrollees. Participation varied significantly across ethnic groups. Non-Hispanic whites were more likely to be enrolled in clinical trials (EF, 1.2%) than African Americans (EF, 0.7%; P < .001) and Hispanics (EF, 0.4%; P < .001). A decrease in African American (6% v 9.2%) and Hispanic (2.6% v 3.1%) enrollment was observed when compared with historical data from 1996 to 2002. Younger patients (age younger than 65 years) were more likely to be enrolled in clinical trials than the elderly (64% v 36%; P < .001). Low recruitment of female patients was observed in clinical trials for melanoma (35%), lung cancer (39%), and pancreatic cancer (40%). Conclusion: We observed a decrease in recruitment of minorities over the past 14 years compared with historical data. African Americans, Hispanics, and women were less likely to be enrolled in cancer clinical trials. Future trials should take extra measures to recruit participants that adequately represent the US cancer population.