Molina, Julian R.

Abstract The metabolic signatures of cancer cells are often associated with elevated glycolysis which promotes alteration in cellular bioenergetics. 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), a critical control point in the glycolytic pathway has emerged as a potential anti-cancer target associated with many aspects of neoplastic progression. Pharmacological (PFK158 treatment) and genetic inhibition of PFKFB3 activity, decreases glucose uptake, ATP production, and lactate dehydrogenase activity and inhibits cell proliferation in vitro by arresting the cells in the G0/G1 phase induced cell death in malignant pleural mesothelioma (MPM). It induces an early response of increased macropinocytosis and drastic endosomal vacuolization to overcome the nutrient stress both in sarcomatoid (H28) and epithelioid (EMMeso) MPM cells. Inhibition of PFKFB3 leads to the activation of the endocytic Rac1-Rab5-Rab7 pathway resulting in a unique form of cell death called “methuosis”. Transmission Electron Microscopy analysis showed that pharmacological and genetic inhibition of PFKFB3 activity leads to the formation of nascent macropinocytotic vesicles, which rapidly coalesced to form large vacuoles with compromised lysosomal function. Confocal microscopy revealed F-actin and α-tubulin disassembly leading to the disruption of cell structure integrity. In parallel, PFKFB3 expression inversely modulates endoplasmic reticulum (ER) stress in MPM. Pharmacological and genetic inhibition of PFKFB3 led to an escalation in ER activity and aggravated ER stress mostly by upregulating BiP and GADD153 expression levels. However, EHT1864, a Rac1 inhibitor, could not rescue MPM cells from ER stress, suggesting that the activation of macropinocytosis and ER stress are a result of two independent PFKFB3 modulated adaptive responses. Both immunofluorescence microscopy and co-immunoprecipitation analyses revealed that the two crucial biomolecules of each pathway, Rac1 and Calnexin, interact with each other only at the later stages of PFKFB3 inhibition. Finally, PFK158, in a combination of with CBPt, demonstrated a significant reduction in tumor weight in mesothelin overexpressed EMMeso xenograft model. Since most cancer cells exhibit an increased glycolytic rate, these results provide evidence for PFK158, in combination with standard chemotherapy, may have a potential in the treatment of MPM. Citation Format: Sayantani Sarkar Bhattacharya, Ling Jin, Debarshi Roy, Deokbeom Jung, Prabhu Thirusangu, Yinan Xiao, Julie Staub, Julian Molina, Viji Shridhar. PFKFB3 inhibition reprograms malignant pleural mesothelioma to glycolytic stress-induced macropinocytosis and ER stress as independent binary adaptive responses [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 2658.

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]

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.

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.