Adjei, Alex A.

e20639 Background: Multiple randomized controlled trials (RCTs) have shown a robust benefit of immunotherapy with immune checkpoint inhibitors (ICI) in non-small cell lung cancer (NSCLC). We did a meta-analysis to examine the benefit of ICI in various subgroups. Methods: PubMed was searched up to Jan 15, 2019 for RCTs comparing overall survival (OS) between ICI and control (without ICI) arms. Pooled hazard ratio (HR) and 95% confidence interval (CI) was calculated for each subgroup. Interaction tests were done to compare relative benefit between opposed subgroups of interest (eg. men vs women; reported as Pheterogeneity). All analyses were performed with a random effects model in Comprehensive Meta Analysis (v2). Results: Twelve phase 2/3 RCTs involving 7244 patients were included. A significant OS benefit of ICI was found in both squamous and non-squamous histology. Current/former smokers, EGFR wild-type, and KRAS mutant patients had a significant OS benefit from ICI, but never smokers, EGFR mutant, and KRAS wild-type patients did not. An OS benefit of ICI was found in patients with or without baseline brain metastasis, PD-L1 < 1% or ≥1%, men or women, age < 65 or ≥65, and ECOG PS 0 or ≥1. No significant difference of relative benefit from ICI over control was found in patients with different PD-L1 expression, sex, age, or ECOG PS (Table). Conclusions: OS benefit of ICI in NSCLC was associated with a smoking history, wild-type EGFR or KRAS mutation. However, the OS benefit of ICI was seen regardless of histology, PD-L1 expression, sex, age, and ECOG PS. [Table: see text]

3101 Background: PDO is a promising translational tool that recapitulates the biology and drug response of donor cancer patient. However, an unmet need is to have PDO drug-screening data available for treatment decision making in clinic. We conducted a pilot study to determine whether PDO testing results will be available at critical treatment decision points in metastatic GI cancer patients. Methods: Metastatic GI cancer patients undergoing core-needle biopsy were eligible. Tumor cells isolated from ≤4 fresh biopsy tissues were grown in a Matrigel-based culture. PDO response to anti-cancer drugs were evaluated; and when available, correlated with donors’ clinical response to the same agent(s). PDO response was defined as IC50 < 0.1 × published Cmax of the drug clinically; stable as IC50 between 0.1 to 10 × Cmax. Radiographic response was per RECIST criteria. Results: We enrolled 27 refractory metastatic GI cancer patients (9 colorectal [CRC], 9 pancreas, and 9 biliary tract). Median lines of therapy were 4, 2, and 2; the success rate of organoid establishment was 89%, 44%, and 55%, respectively. The median time from biopsy to availability of drug-testing data was 64 days (range: 24 to 93 days). The median time from biopsy to next CT re-staging in donors was 64 days. The established PDOs shared histological and genomic features with donor clinical tissue. PDO and clinical responses to the same agent(s) were correlated in 2 CRC donors including (1) BRAFV600E-mutated PDO responded to vemurafenib + panitumumab, as did the donor who had partial response (PDO drug-testing data were available 55 days post-biopsy, 23 days prior to restaging scan); (2) KRAS/FGF-dual amplified PDO had stable disease status to regorafenib, as did the biopsied lesion from the donor (73 days post-biopsy, 5 days post-scan). Conclusions: We showed the feasibility of completing PDO drug sensitivity testing in metastatic GI cancer patients within a short time that could impact clinical decision making, particularly in CRC. PDO drug response showed correlation with clinical response. With further refinement, PDO can be a powerful tool for personalizing cancer therapy in metastatic GI cancer patients.

2621 Background: TMB is an emerging predictor of survival with immunotherapy. TMB is determined by taking the difference between somatic and germline datasets when tumor-normal pairs are available. In the case of commonly utilized tumor-only sequencing, additional steps are needed to estimate the somatic alterations. Computational tools have been developed that determine germline contribution based on sample copy state, purity estimates and occurrence of the variant in population databases. Given the potential bias of population datasets, we hypothesized that tumor-only filtering approaches may overestimate the actual TMB. Methods: We assessed the TMB from 50 tumors in 10 diseases including all missense, indels, and frameshift variants with an allelic fraction (AF) ≥5% and Coverage ≥100X within the tumor. Tumor-only TMB was evaluated against the gold standard of matched germline subtracted TMB at three levels. Level 1 removed all the tumor-only variants with AF in the non-TCGA ExAC database ≥1%. Level 2 removed all variants observed in population databases simulating a naive approach of removing germline variation. Level 3 used an internal tumor-only pipeline for calculating TMB. Results: There were significantly higher estimates of TMB with Level 1, Level 2 and Level 3 tumor-only filtering approaches than that determined by germline subtraction, resulting in significant bias. Whereas there was no correlation between TMB estimates and tumor-germline TMB for Level 1 filtering, there were improvements in correlations for Level 2 and Level 3. Conclusions: The tumor-only approaches that filter variants in population databases overestimate TMB compared to that determined by germline subtraction. Despite improved correlations with more stringent filtering approaches, these falsely elevated estimates may result in the inappropriate categorization of tumor specimens and negatively impact clinical trial results and patient outcomes. [Table: see text]

TPS2075 Background: IDH mutant astrocytomas express high levels of 2-hydroxyglutarate (2-HG), an oncogenic metabolite which drives gliomagenesis. Excess 2-HG inhibits branched chain amino acid transaminase, which catalyzes glutamate synthesis from branched chain amino acids. This defect causes these tumors to become more reliant on glutaminase for glutamate biosynthesis from glutamine. CB-839 (telaglenastat) is a novel glutaminase inhibitor which is well tolerated in humans. McBrayer et al have recently demonstrated that CB-839 further depletes intracellular glutamate and glutathione in IDH mutant glioma cells, and enhances RT (radiation therapy) efficacy in an orthotopic glioma model. Methods: NCI #10218 is a CTEP supported phase I clinical trial investigating the safety and tolerability of CB-839 when combined with RT/TMZ (temozolomide) in patients with previously untreated IDH mutant grade II/III astrocytoma. Patients with grade II and III astrocytomas will be treated with 50.4 and 59.4 Gy of RT, respectively, with standard doses of concurrent TMZ. CB-839 will also be administered orally concurrently with RT, with doses escalated in cohorts based on a standard 3+3 design. After defining the maximum tolerated dose (MTD) of CB-839, an expansion cohort will evaluate the pre- and post-CB-839 therapy metabolome of patients with IDH mutant astrocytoma. Enrollment to this cohort will require measurable disease and patients will additionally be treated with a 7 day run-in of CB-839 at MTD prior to RT. The effect of CB-839 on the metabolome will be studied in both plasma (LC/MS/MS) and tumor (magnetic resonance spectroscopy), along with PK to confirm adequacy of systemic exposure. Preliminary data on neurocognitive endpoints will also be acquired. NCI #10218 is currently activated for enrollment to cohort 1. Clinical trial information: NCT03528642.

Abstract Background Immune-related adverse events (irAEs) have emerged as a serious clinical issue in the use of immune checkpoint inhibitors (ICIs). Risk factors for irAEs remain controversial. Therefore, we studied sex differences in irAEs in patients treated with anti-programmed cell death protein 1 (PD-1) therapy. Materials and Methods All patients with metastatic melanoma and non-small cell lung cancer (NSCLC) treated with anti-PD-1 therapy at Mayo Clinic Rochester and Florida from 2015 to 2018 were reviewed. Kaplan-Meier method and log-rank test was used for time-to-event analysis. Results In 245 patients with metastatic melanoma, premenopausal women were more likely to experience irAEs (all grades) compared with postmenopausal women and men (67% vs. 60% vs. 46%), primarily because of an increase in endocrinopathies (33% vs. 12% vs. 10%, respectively). In patients with NSCLC (231 patients), women (all ages) were also more likely to develop irAEs of all grades (48% vs. 31%). Women with NSCLC were more likely to develop pneumonitis (11% vs. 4%) and endocrinopathies (14% vs. 5%). No differences in grade ≥3 toxicities were seen across sexes in both cohorts, but women were more likely to receive systemic steroids for the treatment of irAEs compared with men. Better progression-free-survival was observed in women with NSCLC and irAEs (10 months vs. 3.3 months) compared with women without irAEs. Conclusion Women with metastatic melanoma and NSCLC are more likely to experience irAEs compared with men. We also observed differences between sexes in the frequency of certain irAEs. Larger studies are needed to investigate the mechanisms underlying these associations. Implications for Practice The results of this study suggest that women may be at a higher risk for immune-related adverse events (irAEs) compared with men when treated with anti-programmed cell death protein 1 therapy. In addition, women were more likely to develop certain irAEs, including endocrinopathies and pneumonitis. Close follow-up of women undergoing treatment with immune checkpoint inhibitors will allow clinicians to diagnose these treatment-related complications early, potentially reducing their associated morbidity and mortality. In addition, a possible association between irAEs and response to therapy was observed.

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.

Abstract Background Early phase clinical trials evaluate the safety and efficacy of new treatments. The exclusion/inclusion criteria in these trials are usually rigorous and may exclude many patients seen in clinical practice. Our objective was to study the comorbidities limiting the participation of patients with breast, colorectal, or lung cancer in clinical trials. Materials and Methods We queried ClinicalTrials.gov on December 31, 2016. We reviewed the eligibility criteria of 1,103 trials. Logistic regression analyses were completed, and exclusion was studied as a binary variable. Results Out of 1,103 trials, 70 trials (6%) excluded patients &gt;75 years of age, and 45% made no reference to age. Eighty-six percent of trials placed restrictions on patients with history of prior malignancies. Regarding central nervous system (CNS) metastasis, 416 trials (38%) excluded all patients with CNS metastasis, and 373 (34%) only allowed asymptomatic CNS metastasis. Regarding chronic viral infections, 347 trials (31%) excluded all patients with human immunodeficiency virus, and 228 trials (21%) excluded all patients with hepatitis B or C infection. On univariate analysis, chemotherapy trials were more likely to exclude patients with CNS metastasis and history of other malignancies than targeted therapy trials. Multivariate analysis demonstrated that industry-sponsored trials had higher odds of excluding patients with compromised liver function. Conclusion Many clinical trials excluded large segments of the population of patients with cancer. Frequent exclusion criteria included patients with CNS metastasis, history of prior malignancies, and chronic viral infections. The criteria for participation in some clinical trials may be overly restrictive and limit enrollment. Implications for Practice The results of this study revealed that most early phase clinic trials contain strict exclusion criteria, potentially excluding the patients who may be more likely to represent the population treated in clinical settings, leaving patients susceptible to unintended harm from inappropriate generalization of trial results. Careful liberalization of the inclusion/exclusion criteria in clinical trials will allow investigators to understand the benefits and drawbacks of the experimental drug for a broader population, and possibly improve recruitment of patients with cancer into clinical trials.

Objectives: Preclinical studies demonstrated antitumor activity of dovitinib in pancreatic cancer models. This phase Ib study aimed to determine the maximum tolerated dose (MTD) of dovitinib in combination with gemcitabine and capecitabine and to characterize the safety and pharmacokinetic profile in patients with advanced pancreatic and biliary tract cancers and solid malignancies. Materials and Methods: Patients received gemcitabine 1000 mg/m² intravenously on days 1 and 8, capecitabine 1300 mg/m² oral daily from day 1 to 14, and dovitinib oral daily 5 days on and 2 days off, every 21-day cycle. The standard 3+3 dose escalation design was utilized and the study expanded to treat an additional 20 advanced pancreatic and biliary tract cancers patients at MTD. Results: A total of 29 patients were enrolled. One patient experienced dose-limiting grade 3 colitis. Two patients developed clinically significant neuropathy after the first cycle requiring dose reduction. The MTD was not reached and dovitinib 300 mg was declared the recommended dose for expansion. The most frequent grade 2 or worse adverse events were fatigue (45%), neutropenia (41%), thrombocytopenia (34%), anemia (24%), nausea (24%), and palmer-plantar erythrodysaesthesia syndrome (21%). Partial responses were observed in 5 patients. Pharmacokinetic studies showed no drug-drug interaction between dovitinib, capecitabine and gemcitabine. Fibroblast growth factor 23 plasma level increased in 4 of 5 patients during the first cycle of treatment. Conclusions: Dovitinib 300 mg daily is the recommended dose when combined with gemcitabine and capecitabine, achieving clinically relevant plasma concentrations. The study combination demonstrated encouraging efficacy signals in advanced pancreatic cancer.