Combination Of Inhibitors Research Articles

Abstract PO1-03-07: Revisiting the potential of pathological complete response as a surrogate for long-term survival outcomes in triple-negative breast cancer at the trial-level

Abstract Background: Pathological complete response (pCR) has been used as a primary endpoint in neoadjuvant clinical trials for non-metastatic breast cancer and as a surrogate endpoint for long-term survival outcomes. The U.S. Food and Drug Administration (FDA) accepted pCR as a surrogate endpoint for the approval of new drugs in the neoadjuvant setting in high-risk early-stage breast cancer. However, though the Collaborative Trials in Neoadjuvant Breast Cancer (CTNeoBC) pooled analysis in 2014 showed that at the patient level achieving pCR was associated with longer overall survival (OS) and event-free survival (EFS), at the trial-level the association between high pCR rate and better OS and EFS outcomes was weak (coefficient of difference [R2]; 0.03 and 0.24, respectively) among all subtypes of breast cancer. A recent study reported that this association at the trial-level was similarly weak among Human Epidermal Growth Factor Receptor-2 (HER-2) positive breast cancer (R2; 0.02 and 0.23, respectively). However, the potential surrogacy of pCR rate for OS and EFS in triple-negative breast cancer (TNBC) in the neoadjuvant setting has not been well studied in a comprehensive manner. Moreover, because of significant advances in systemic treatment strategies in TNBC over the past decade including a combination of immune checkpoint inhibitors (ICIs) with conventional cytotoxic agents, the trial-level surrogacy needs to be reassessed in recently published neoadjuvant clinical trials for TNBC. Our primary objective is to assess the association between pCR rate and survival outcomes in neoadjuvant clinical trials for TNBC by collecting data from articles published after the CTNeoBC article in 2014. Methods: We performed a systematic literature search based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in the PubMed, Cochrane Library, and Web of Science databases. Articles published between January 1, 2014, and March 31, 2023, were searched. We included only randomized control trials of neoadjuvant treatments for clinical stage I-III TNBC that compared two or more regimens followed by curative intent breast surgery. The selected trials had data for odds ratio (OR) for pCR and hazard ratios (HRs) either for OS or for EFS or disease-free survival (DFS). We excluded trials including estrogen receptor positive, progesterone receptor-positive, or HER-2 positive diseases, and those without data enough to obtain ORs for pCR, HRs for OS, EFS, or DFS. Unpublished data as a full article was also excluded. If EFS could not be obtained from the articles, DFS was used in place of EFS. Two independent investigators (TY and TF) searched and extracted data. Any disagreement was resolved by discussion with the third author (ZZ). A linear regression model on a logarithmic scale weighted by the sample size of each trial was performed and the R2 was used to assess the trial-level association between OR for pCR and HRs for OS or EFS. Results: We identified eight trials with a total of 2,926 patients. Three of the eight trials used ICIs in the intervention arm. One trial did not provide OS data and was not included in the OS analysis. In four trials, EFS was not available and DFS was used for EFS analysis. The R2 was 0.191 (95% confidence interval [CI], 0.165 to 0.218) for OS and 0.193 (95% CI, 0.167 to 0.219) for EFS. Conclusions: Similarly to the previous reports, our findings suggest that the surrogacy of the pCR rate for OS and EFS in recent neoadjuvant clinical trials for TNBC is weak. At this moment, there is no strong evidence to support using pCR as a surrogate for long-term survival outcomes in neoadjuvant clinical trials for TNBC. Citation Format: Toru Yoshino, Zao Zhang, Ryota Sato, Stanley Lipkowitz, Takeo Fujii. Revisiting the potential of pathological complete response as a surrogate for long-term survival outcomes in triple-negative breast cancer at the trial-level [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-03-07.

Abstract LBO1-02: Pathologic complete response (pCR) of neoadjuvant therapy with or without atezolizumab in HER2-positive, early high-risk and locally advanced breast cancer: APTneo Michelangelo randomized trial

Abstract Background: Neoadjuvant dual targeting of HER2 with trastuzumab (H) and pertuzumab (P) plus chemotherapy is the standard of care for high-risk HER2-positive (HER2+) breast cancer (BC). Compelling data show the contribution of the immune system in prognosis and response/resistance to HER2 directed therapies, supporting combination of immune checkpoint inhibitors with anti HER2 antibodies. We designed APTneo to test the role of adding atezolizumab to neoadjuvant dual targeting of HER2 with chemotherapy, and the value of also using anthracyclines in this setting. Methods: In this multicenter open label phase III trial (NCT03595592), 661 patients (pts) with high-risk early and locally advanced (LA) centrally confirmed HER2+ BC were randomized to neoadjuvant HPCT (H and P d1, carboplatin and paclitaxel iv d1 and 8) given q3 wks for 6 cycles w/o (n=223, ARM A) or with atezolizumab 1200 mg iv d1 (n=438, ARM B). In Arm B pts were randomized to Arm B1 (n=218) to receive anthracycline and cyclophosphamide (AC) + atezolizumab iv d1 q3 wks for 3 cycles followed by HPCT + atezolizumab for 3 cycles, or to arm B2 (n=220) to receive HPCT + atezolizumab for 6 cycles. After surgery pts continued adjuvant HER2 directed therapies w/wo atezolizumab until completion of 1 year. Among intent-to-treat (ITT) pts, 44.8% were LABC, 35% hormonal receptor (HR) negative and 30.4% PD-L1 positive. Primary endpoint is event-free survival (EFS) of Arm B vs A. A key secondary endpoint is the rate of pCR (ypT0/Tis, ypN0) w/wo atezolizumab. Primary population for all efficacy endpoints is ITT. We also assessed baseline PD-L1 status (Ventana SP142) and stromal Tumor Infiltrating Lymphocytes (sTILs). Results: pCR rate in Arm B (57.8%) vs Arm A (52.0%) was not significantly increased (adjHR 1.33, 95% CI 0.95-1.86; p=0.091). Also, the difference in pCR rate in Arm B1 (61.9%) vs Arm B2 (53.6%) was not significant (adjHR 1.402, 95% CI 0.95-2.07; p=0.089). Compared to Arm A, Arm B1 had a 9.9% significantly higher pCR rate (multivariate analysis in Table). The different pCR rate in arms B1 and A was similar regardless of HR and PD-L1 status. High sTILs (≥30%) and PD-L1positive tumors had a higher likelihood of pCR in all arms. Serious adverse events (SAE) after start of therapy occurred in 6.8% pts in Arm A and 14.1% in Arm B (p=0.0064). SAE were numerically more frequent in Arm B1 than Arm B2 (16.7% and 11.6%, respectively), due to hematological toxicity with AC. Immune-related SAE were quite infrequent and similar in B1 (4.7%) and B2 (7.8%), respectively. No grade 5 AE did occur. Conclusions: Addition of atezolizumab to chemotherapy and HP did not significantly increase the rate of pCR in women with HER2+ BC. An exploratory analysis showed that adding atezolizumab to neoadjuvant AC followed by HPCT led to higher pCR rate compared to HPCT and atezolizumab. This could be because of anthracyclines themselves or to drug-drug enhancement of anthracyclines and immune modulation. Atezolizumab did not cause major tolerability issues. Molecular studies of collected biospecimens are ongoing. Patients will continue to be followed up for EFS and overall survival analyses. Table. Supported in part by unrestricted grant from Hoffman-La Roche, Ltd, Switzerland Citation Format: Luca Gianni, Elisabetta Munzone, Mauro Mansutti, Giampaolo Bianchini, Yann Izarzuzaga, Elena Rota Caremoli, Luc Dirix, Lucia Del Mastro, Santiago González-Santiago, Andreas Schneeweiss, Jose Ponce, Chiun-Shen Huang, Pauline Wimberger, Sevilay Altintas, Miguel Martín, Nicoleta Antone, Christian F. Singer, Ugo De Giorgi, Ana Godoy Ortiz, Hans-Joachim Lueck, Riccardo Spezia, Angelica Fasolo, Giuseppe Viale, Pinuccia Valagussa. Pathologic complete response (pCR) of neoadjuvant therapy with or without atezolizumab in HER2-positive, early high-risk and locally advanced breast cancer: APTneo Michelangelo randomized trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr LBO1-02.

Abstract PS09-09: Multiomics profiling and molecular classification refine precision treatment strategies for HER2-positive breast cancer

Abstract Background: Anti-HER2 targeted therapy has achieved a series of breakthroughs. However, the current treatment strategy regarding HER2-positive breast cancer remains indiscriminate and lacks specificity, which limits the further improvement of overall treatment response and may lead to overtreatment and extra cost for some patients. Our study aims to reveal the molecular heterogeneity of HER2-positive breast cancer to guide a more precise treatment. Patients and methods: We selected HER2-positive breast cancer patients treated at Fudan University Shanghai Cancer Center between 2013 and 2014 and conducted genomic, transcriptomic, proteomic and metabolomic profiling. We then applied a non-negative matrix factorization algorithm on transcriptomic data to obtain an unsupervised classification. And we further studied the correlation between subtypes and corresponding treatment strategies in multiple cohorts of adjuvant and neoadjuvant therapy. For clinical accessibility, we developed convolutional neural network models through deep learning algorithm based on digital pathology to identify different subtypes. Additionally, we explored novel treatment strategies using the patient-derived organoids (PDOs) models. Results: We established a novel multiomics cohort of 180 HER2- breast cancer patients and classified them into four clinically significant molecular subtypes: (1) A classical HER2-enriched (HER2-CLA, N=51) subtype characterized by strong ERBB2 signaling and remarkable sensitivity to anti-HER2-targeted therapy (pathologic complete response with dual-targeted therapy: 93%). (2) an immunomodulatory (HER2-IM, N=36) subtype characterized by an immune-activated microenvironment and excellent prognosis with current treatment (no relapse in 97% of patients with a median follow-up of 86 months). Tumors of this subtype were therefore candidates for de-escalatory treatment. (3) A luminal-like (HER2-LUM, N=55) subtype distinguished by activated estrogen receptor signaling and (4) a basal/mesenchymal-like (HER2-BM, N=38) subtype enriched in activated receptor tyrosine kinase pathways. HER2-LUM and HER2- BM showed limited benefit from anti-HER2 therapy, and thus, add-on therapies might be needed. The overall area under the curve (AUC) of the convolutional neural network model based on digital pathology for identifying different subtypes is 0.77. In the exploration of novel treatment strategies, we found in the PDO model that the HER2-LUM subtype is more sensitive to a treatment regimen combining standard (chemotherapy and targeted therapy) with subsequent endocrine therapy and CDK4/6 inhibitors compared to other subtypes. Additionally, the HER2-BM subtype demonstrated greater sensitivity to treatment with a combination of EGFR inhibitors, PDGFR inhibitors or VEGFR inhibitors. Conclusion: We uncovered a high degree of molecular heterogeneity in HER2-positive breast cancer and illustrated its impact on treatment response. More precise treatment can be given according to the characteristics of different subtypes, which may achieve good efficacy and simultaneously reduce overtreatment and extra cost. The comprehensive profiling of HER2-positive breast cancers could also serve as an important resource for further exploration. Key Words: HER2-positive breast cancer cohort; molecular classification; targeted therapy; precision treatment; de-escalatory treatment. Citation Format: Yu-Wei Li, Ding Ma, Xiang-Rong Wu, Lei-Jie Dai, Shen Zhao, Yu-Zheng Xu, Xi Jin, Xiao Yi, Ying Wang, Cai-Jin Lin, Yi-Fan Zhou, Tong Fu, Wen-Tao Yang, Ming Li, Hong Lv, Yi-Zhou Jiang, Zhi-Ming Shao. Multiomics profiling and molecular classification refine precision treatment strategies for HER2-positive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS09-09.

Abstract PS17-08: A Phase Ib Study to Evaluate the Efficacy and Safety of Afuresertib Plus Fulvestrant in Patients with Locally Advanced or Metastatic HR+/HER2- Breast Cancer Who Failed Standard of Care Therapies

Abstract Background The combination of an aromatase inhibitor with a CDK4/6 inhibitor is the mainstay of first-line endocrine therapy (ET) for locally advanced or metastatic HR+/HER2− breast cancer (LA/mBC). Management of recurrent disease in the post-CDK4/6 inhibitor setting includes additional lines of ET single agent or in combination with a targeted agent. For patients with HR+/HER2− LA/mBC tumors, fulvestrant monotherapy as the second- or third-line therapy has limited activity with a median PFS of 1.9-3.6 months. Effective targeted treatments for these patients are needed to maintain quality of life, improve survival, and delay the initiation of cytotoxic chemotherapy. Methods This ongoing single arm, open-label global study (NCT04851613) is to evaluate the efficacy and safety of the combination therapy of afuresertib (a pan-AKT inhibitor) plus fulvestrant in patients with HR+/HER2− LA/mBC. Eligible patients must have received 1-2 prior lines of ET. Patients may have prior treatment of CDK4/6 inhibitors (up to 1 therapy), and/or up to 1 line of chemotherapy. Patients received afuresertib (125 mg PO, QD) in combination with fulvestrant (500 mg IM; Day 1 and 15 in Cycle 1, and Day 1 in subsequent 28-day cycles). The safety of the initial treatment doses of the combination therapy was evaluated in the first 6 patients during the Cycle 1 safety run-in period. Radiographic assessment per RECIST 1.1 was performed every 8 weeks for the first 6 cycles and every 12 weeks thereafter. The primary endpoint was the investigator-assessed objective response rate (ORR). The secondary endpoints included safety and tolerability of the combination therapy and pharmacokinetic characterization. Results Twenty patients (1 male and 19 females, 3 in the US and 17 in China) were enrolled between May 2022 and April 2023. As of the data cut-off date of May 26th, 2023, 10 patients had discontinued the study treatment (9 due to disease progression, 1 due to patient’s withdrawal of consent) and 10 patients were still in treatment. Of the 19 patients who had at least one post-baseline tumor assessment, 4 patients observed confirmed Partial Response (cPR), 12 had best overall response of Stable Disease, and 3 had Progressive Disease (PD). The Disease Control Rate is 84%. Of the 15 patients who had at least 2 tumor assessments or who discontinued treatment early due to PD, the confirmed ORR is 26.7% (4 cPR). No dose modification was required during the safety run-in. The most common treatment-emergent adverse events (TEAEs, > 20% of patients) of all grades were hyperglycemia (50%), diarrhea (45%), ALT/AST increase (40%), nausea (35%), rash (35%), hypercholesterolemia (35%), and anemia (30%), the majority of which were Grade 1. Grade 3 AEs were reported in 4 patients, including diarrhea (1 patient), WBC increase (1 patient), creatine phosphokinase increase (1 patient), and ALT/AST increase and rash (1 patient). No SAE or TEAE >= Grade 4 were reported. No patient discontinued treatment due to TEAE. Conclusions The preliminary data from the combination therapy of afuresertib plus fulvestrant has shown promising efficacy with a well-tolerated safety profile in patients with HR+/HER2− LA/mBC who progressed on 1-2 prior lines of standard of care therapies. These results support further evaluation of this combination therapy in this patient population in an upcoming phase III study. Citation Format: Binghe Xu, Pin Zhang, Tao Sun, Ying Wang, Zhongsheng Tong, Sneha Phadke, Trevor Feinstein, Pengfei Guo, Jing Qu, Xiaoyu Wang. A Phase Ib Study to Evaluate the Efficacy and Safety of Afuresertib Plus Fulvestrant in Patients with Locally Advanced or Metastatic HR+/HER2- Breast Cancer Who Failed Standard of Care Therapies [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS17-08.

Abstract PO1-16-03: GDP-mannose enhances the efficacy of PARP inhibitors and immunotherapy in triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) patients with high HRD scores benefit from poly (ADP-ribose) polymerase (PARP) inhibitors, while those with low HRD scores still lack therapeutic options. Homologous recombination deficiency (HRD) induction is an effective strategy to broaden the indications of PARP inhibitors. Metabolic reprogramming is a critical feature of TNBC. In this study, we aimed to explore novel metabolic biomarkers for HRD and new strategy for sensitizing PARP inhibitors. Methods: We utilized TNBC metabolomics to systematically evaluate metabolites that were correlated with HRD. A crucial metabolite, GDP-mannose (GDP-M), that impedes homologous recombination repair (HR) and sensitizes PARP inhibitors was identified and functionally validated. We further explored the detailed mechanism and proposed a potential treatment strategy utilizing GDP-M for TNBC in preclinical models. Results: Systematic metabolomic analysis revealed that GDP-mannose (GDP-M) was significantly enriched in basal-like tumors with HRD. GDP-M promoted cisplatin-induced DNA double-strand breaks by inducing HRD. Mechanistically, the low expression of the upstream enzyme GMPPA led to the endogenous upregulation of GDP-M, which further promoted the ubiquitin-mediated degradation of BRCA2 to inhibit HR. GMPPA expression and GDP-M could serve as predictive biomarkers for HRD and the response to PARP inhibitors. Therapeutically, we validated that the combination of GDP-M and PARP inhibitors synergistically inhibit tumor growth in multiple preclinical models. Moreover, GDP-M supplementation plus PARP inhibition activated STING-dependent antitumor immunity and further augmented the efficacy of anti-PD-1 antibodies. Conclusions: GDP-M promotes the degradation of BRCA2 and thus enhances the sensitivity of PARP inhibitors in TNBC. The combination of GDP-M, PARP inhibitors and anti-PD-1 immunotherapy may be a potential treatment strategy for HRD-low TNBC. Citation Format: Yi Xiao, Jiahan Ding, Yi-Zhou Jiang, Zhi-Ming Shao, Genhong Di, Fan Yang, Xiaoqing Song. GDP-mannose enhances the efficacy of PARP inhibitors and immunotherapy in triple-negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-16-03.

Abstract PO1-13-11: ZNF689 promotes homologous recombination via NBS1 ubiquitination and its loss confers sensitivity to PARP inhibition in triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) poses significant clinical challenges due to the lack of targeted therapies and poor prognosis. Homologous recombination (HR) deficiency is a defining characteristic of TNBC and renders tumors susceptible to Poly (ADP-ribose) polymerase (PARP) inhibitors. However, not all TNBC patients respond to PARP inhibitors, highlighting the need to identify novel biomarkers to predict therapeutic response and improve treatment strategies. Methods: In this study, we investigated the role of zinc finger protein 689 (ZNF689) in DNA damage response (DDR) and its impact on PARP inhibitor sensitivity in TNBC. Using a comprehensive set of molecular and cellular techniques, including immunoprecipitation, in vitro and in vivo ubiquitination assays, protein expression analysis, and functional assays using TNBC cell lines, patient-derived organoids (PDOs), patient-derived xenograft (PDX) models, and cell line xenograft models, we elucidated the mechanistic role of ZNF689 in HR and PARP inhibitor response. Results: Our findings revealed ZNF689 as a novel player in DDR. ZNF689 is activated by ATM-mediated phosphorylation and recruited to DNA damage sites in an ATM-dependent manner. At the DNA double-strand break sites, ZNF689 collaborates directly with NBS1 to facilitate K63-linked ubiquitination of NBS1 via the E3 ligase SKP2. Furthermore, ZNF689-mediated NBS1 ubiquitination stabilizes the MRE11-RAD50-NBS1 (MRN) complex and feedbacks activation of ATM, therefore accelerating HR repair. Loss of ZNF689 results in HR deficiency, leading to increased sensitivity of TNBC cells to PARP inhibitors in both in vitro and in vivo models. Additionally, the combination of PARP inhibitors and paclitaxel demonstrated potential for improved efficacy in treating ZNF689-deficient TNBC. In our clinical analysis, we observed a positive correlation between ZNF689 expression and the levels of NBS1 and phosphorylated ATM in TNBC patient samples. Importantly, low ZNF689 expression was associated with a favorable response to PARP inhibitors in TNBC patients. Conclusions: Our study highlights the significant role of ZNF689 in HR and its impact on the response to PARP inhibitors in TNBC. These findings suggest ZNF689 as a promising therapeutic target for enhancing the effectiveness of PARP inhibitors in TNBC patients. Working Modle Citation Format: Li-Ping Ge, Zi-Yu Wang, Xi Jin, Yi-Zhou Jiang, Zhi-Ming Shao. ZNF689 promotes homologous recombination via NBS1 ubiquitination and its loss confers sensitivity to PARP inhibition in triple-negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-13-11.

Abstract PO4-19-09: Comparison of clinical efficacy between letrozole + ribociclib vs. Fulvestrant + letrozole + ribociclib in Hormone receptor positive, HER2 negative metastatic breast cancer – a randomized, phase 2 study (KCSG BR22-20)

Abstract Background The current standard first-line treatment in advanced or metastatic hormone receptor (HR) positive breast cancer is combination of aromatase inhibitor (AI) and cyclin D kinase-4/6 (CDK4/6) inhibitor. Emergence of ESR1 mutation is a key mechanism of resistance during first-line AI + CDK4/6 inhibitor treatment. Selective estrogen receptor downregulator (SERD) such as elacestrant or fulvestrant is suggested as second-line treatment, but the progression-free survival (PFS) outcome of second-line treatment is reported up to 3.78 months in patients who harbour ESR1 mutation. Recently, early switch of AI + CDK4/6 inhibitor to fulvestrant + CDK4/6 inhibitor at the point of rising ESR1 mutation showed prolongation of PFS up to 6 months, suggesting there may be a new strategy to overcome ESR1 mutation by modifying endocrine treatment. SWOG S0226 suggested that upfront fulvestrant + AI is feasible and associated with prolongation of PFS compared to AI alone. After CDK4/6 inhibitor has been introduced to standard treatment, there were no trials evaluating the role of AI + fulvestrant with CDK4/6 inhibitor. In this trial, we investigated triplet combination of AI + fulvestrant + CDK4/6 inhibitor as a treatment to overcome resistant mechanism such as development of ESR1 mutation when compared to current standard treatment of AI + CDK4/6 inhibitor as the first line treatment in HR positive advanced or metastatic breast cancer. Methods This study is a randomized, multicenter, open-label phase II trial comparing AI plus ribociclib versus AI, fulvestrant plus ribociclib in HR-positive advanced or metastatic breast cancer. De novo patients or patients with treatment-free interval (TFI) over 12 months after completion of adjuvant AI can be enrolled. If patients received adjuvant tamoxifen, patients with TFI less than 12 months can be also enrolled for the study. Prior endocrine treatment or cytotoxic chemotherapy at metastatic setting was not allowed. In cases of premenopausal women, gonadotropin releasing hormone agonist (GnRHa) is administered every 4 weeks with treatment. A total of 202 patients will be enrolled for 30 months, and 30 months of follow-up is planned after last-patient enrolment. Patients are randomized to 1:1, stratified based on the presence of visceral metastasis and previous administration of adjuvant AI. Study treatment of the control arm consists of letrozole 2.5mg daily with ribociclib 600mg (Day 1-Day 21 daily by month, 1 week off) until progression. In the experimental arm fulvestrant 500mg intramuscular injection is added (Day 1, Day 15, Day 29 and every 4 weeks thereafter) until progression. For exploratory analysis of ESR1 mutations, circulating tumor DNA (ctDNA) is collected at baseline, and then every 3 months thereafter. Primary endpoint is to evaluate the difference of 24-months PFS rate. Secondary endpoint included PFS, overall survival (OS), emergence and frequency of ESR1 mutation, overall response rate (ORR) and clinical benefit rate (CBR). The analysis is planned after completion of 30 months of follow-up, which provides approximately 90% power to detect superiority 24 months-PFS rate assumed by Kaplan-Meier curve of letrozole + fulvestrant + ribociclib versus letrozole + ribociclib using a log-rank test, assuming a hazard ratio of 0.64 at a two-sided alpha of 0.2. Citation Format: Jieun Lee, Su-Jin Koh, Jung Hye Kwon, Gun Min Kim, Jee Hung Kim, Ho Young Kim, Hee-Jun Kim, Keon-Uk Park, Kyong Hwa Park, Yeon Hee Park, Mi Sun Ahn, Hee Kyung Ahn, Gyeong-Won Lee, Kyoung Eun Lee, Kyung-Hun Lee, Moon Hee Lee, Sung Sook Lee, Jung Lim Lee, Kyung Hae Jung, Joo Young Jung, In Hae Park. Comparison of clinical efficacy between letrozole + ribociclib vs. Fulvestrant + letrozole + ribociclib in Hormone receptor positive, HER2 negative metastatic breast cancer – a randomized, phase 2 study (KCSG BR22-20) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-19-09.

Abstract PO1-19-04: Dalpiciclib and tucidinostat in patients with HR+/HER2- advanced breast cancer and resistance to CDK4/6 inhibitors: A phase Ib trial

Abstract Background: Hormone receptor (HR)-positive/epidermal growth factor receptor 2 (HER2)-negative breast cancer accounts for approximately 70% of all breast cancers and is associated with a better prognosis. Estrogen plays an important role in the growth of HR-positive breast cancer, thus patients with this type of tumor are sensitive to hormone inhibitors. However, a quarter of patients will inevitably relapse. Several large clinical trials have demonstrated that the combination of CDK4/6 inhibitors and endocrine therapy (ET) as first or second-line therapy could improve the progression-free survival (PFS) and overall survival for patients with breast cancer. In China, dalpiciclib (a CDK4/6 inhibitor) in combination with fulvestrant has been approved for patients with recurrent or metastatic HR-positive/HER2-negative breast cancer who have failed ET. Moreover, the combination of dalpiciclib and aromatase inhibitors (AI) as an initial treatment for patients with locally advanced or metastatic HR-positive/HER2-negative breast cancer has also been accepted. However, the standard treatment for patients who have failed CDK4/6 inhibitors has not been established. Histone deacetylase (HDAC) inhibitors cause alterations in gene expression in many signaling pathways associated with oncogenesis, leading to the arrest of tumor cell growth and differentiation, as well as promoting tumor apoptosis. Tucidinostat (an HDAC inhibitor) plus AI has been approved for the treatment of locally advanced HR-positive/HER2-negative postmenopausal breast cancer patients who have failed ET. Theoretically, synergistic effects may occur when HDAC inhibitors are combined with CDK4/6 inhibitors. Currently, the clinical data on combination therapy with CDK4/6 inhibitors and HDAC inhibitors have not been reported. Herein, our study aims to explore the efficacy and safety of dalpiciclib and tucidinostat in patients with late-stage HR+/HER2- breast cancer who have failed CDK4/6 inhibitors. Trial Design: The present study is a single-arm, open-label, phase I, dose escalation clinical trial (NCT 05586841). Patients were assigned to four groups to receive either dalpiciclib 125mg/d and tucidinostat 25mg/BIW (group A) or dalpiciclib 125mg/d and tucidinostat 20mg/BIW (group B) or dalpiciclib 100 mg/d and tucidinostat 25mg/BIW (group C) or dalpiciclib 100 mg/d and tucidinostat 20mg/BIW (group D). The Bayesian Optimal Interval (BOIN) design was performed to determine dose-escalation and de-escalation to find the maximum tolerated dose (MTD) of dalpiciclib plus tucidinostat. Key Eligibility Criteria: The study is enrolling female patients who are older than 18 years, with HR-positive/HER2-negative locally recurrent or metastatic breast cancer (MBC), with Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 2. Before entering this trial, all patients must have received ≤1 previous line of chemotherapy for recurrent or MBC, and have failed CDK4/6 inhibitor therapy. Aims: The BOIN design is employed to explore the optimal dose combination of dalpiciclib and tucidinostat and determine recommended doses for a phase II dose expansion clinical trial, based on prespecified dose-limiting toxicity (DLT). Statistical Methods: Safety will be evaluated in the safety set including all patients who received at least one dose of study treatment and underwent at least one safety assessment. Efficacy will be assessed in the full analysis set, defined as all patients who received at least one dose of study treatment. Present and Planned Accrual: Up to 30 participants were planned to be enrolled in the present study. The first participant was enrolled on 18 January 2023. The recruitment is ongoing. Citation Format: Tao Wang, Jinmei Zhou, Xuexue Wu, Zefei Jiang. Dalpiciclib and tucidinostat in patients with HR+/HER2- advanced breast cancer and resistance to CDK4/6 inhibitors: A phase Ib trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-19-04.

Abstract PO3-06-12: Targeting Fatty Acid Synthase in Brain Metastatic Triple-negative Breast Cancer

Abstract Introduction: Treating triple-negative breast cancer (TNBC) is challenging due to the lack of clearly defined and targetable biomarkers, and treatment options become increasingly limited with TNBC brain metastases (BM). Since the brain microenvironment has relatively low lipid availability, breast cancer cells that colonize the brain increase their reliance on the endogenous biosynthesis of fatty acids. This reveals a potential metabolic vulnerability that can be targeted, and fatty acid synthase (FASN) inhibition has been shown to decrease breast cancer cell invasion in preclinical models. Methods: In our study, we utilized the TNBC cell line MDA-MB-231-Luc/GFP, its brain-seeking subclone, MDA-MB-231-BR-GFP, and two novel cell lines generated from patient-derived organoids obtained from serial collection of brain-metastatic TNBC resections from the same patient, denoted PDO-BC25 and PDO-BC25-2. Cell lines were screened with FASN inhibitors as single agents vs. combined with SN-38 (topoisomerase I inhibitor) and synergy was assessed by the Chou-Talalay method. To characterize signaling changes with FASN inhibition and identify any off-target signaling, we used a Nanostring metabolic pathways nCounter panel to perform differential expression analysis on cells treated with the FASN inhibitor, TVB-2640, vs. vehicle control across the four cell lines. This panel detects the expression of 768 metabolism-related genes. We used 4 biological replicates per sample and the Benjamini-Hochberg statistical method to control for the false discovery rate after performing a t-test to calculate P-values. In addition, we performed spheroid outgrowth assays to identify any phenotypic impacts of FASN inhibition on spheroid outgrowth. Results: Combinatory drug screening between FASN inhibitors and SN-38 revealed synergy in MDA-MB-231-BR-GFP, PDO-BC25, and PDO-BC25-2, but not in the parental MDA-MB-231-Luc/GFP. The Nanostring nCounter metabolic pathways panel identified direct target engagement where FASN, SCD, and the transcription factor SREBP1 were significantly upregulated in the cells treated with TVB-2640 compared to vehicle control (P-adjusted < 0.05). Other upregulated genes were related to the pentose phosphate pathway, nucleotide salvage and synthesis, reactive oxygen species response, amino acid synthesis and transport, and autophagy. Genes that were down-regulated are involved in cell cycle progression, deoxynucleotide synthesis, DNA damage repair, fatty acid oxidation, and cytokine and chemokine signaling. Moreover, despite no decrease in cell viability, TVB-2640 alone was able to slow the outgrowth and invasion of Matrigel-embedded spheroids in a spheroid outgrowth assay. Conclusions: In our study, we have shown that the combination of SN-38 and FASN inhibitors is synergistic in the TNBC brain-seeking cell lines, and that FASN inhibition alone causes on-target transcriptome-level changes and a decrease in spheroid invasion. Next, we plan on testing the brain-metastatic potential of these cell lines in the presence and absence of a FASN inhibitor using an organ-on-chip microfluidic device developed by our lab that mimics the blood-brain barrier, to identify if this strategy has a potential role in prevention of brain metastases. Further studies to refine the molecular basis of the mechanism of action of the combination are underway. Citation Format: Habib Serhan, Liwei Bao, Xu Cheng, Matthew Soellner, Sofia Merajver, Aki Morikawa, Nathan Merrill. Targeting Fatty Acid Synthase in Brain Metastatic Triple-negative Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-06-12.

Abstract PO4-20-04: A Randomized Window of Opportunity Study of Preoperative Letrozole and Simvastatin Versus Letrozole Alone in Stage I-III Hormone Receptor Positive, HER2 Negative Breast Cancer

Abstract Hormone receptor positive (HR+), HER2 negative (HER2-) breast cancers are poor responders to immunotherapy. There is a need for innovative approaches to improve immune responses in these tumors. The combination of statins and aromatase inhibitors have demonstrated antiproliferative and immunomodulatory properties. However, this combination has never been studied in the preoperative setting; thus, our ongoing study represents an opportunity to investigate this approach. We designed a randomized two-arm presurgical “window of opportunity” trial to evaluate the effects of letrozole and simvastatin versus letrozole alone 14 days prior to surgery. Tissue and blood will be obtained at baseline and 14 days after completion of therapy at the time of surgery. Inflammatory markers in the blood and multiplex immunohistochemistry (IHC) in tissue will be assessed. To be eligible for the trial, participants must be postmenopausal women with histologically confirmed stage I-III HR+, HER2- invasive breast cancer with baseline ki-67 ≥10% that have not received prior chemotherapy, endocrine therapy, and/or immunotherapy within 3 months prior to trial enrollment. They should also not have received any cholesterol lowering medication within 3 months prior to trial enrollment. The primary objective is to determine if the addition of simvastatin to letrozole compared to letrozole alone will result in a decrease in geometric mean % change in ki-67 from pre-surgical baseline to 14 days following preoperative therapy. Ki-67 is a validated surrogate marker for disease-free survival in HR+, HER2- breast cancer. The main secondary objective is to determine if the addition of simvastatin to letrozole compared to letrozole alone will result in increased immune activation from pre- to post-treatment based on the evaluation of the immune subtype composition in tissue via multiplex immunofluorescence. We aim to enroll 16 patients in each arm to achieve 90% power and detect a minimum difference of 7.5% in ki-67 using a two-sided Mann-Whitney U or Wilcoxon Rank-Sum test. After accounting for a possible drop off rate of 20%, the study’s target accrual will be 40 participants. Statistical analyses will be performed using SAS 9.4. the significance level will be set at alpha = 0.1. Descriptive statistics will be applied to tissue and blood biomarkers of interest at 2 designated time points, prior to preoperative therapy and following completion of preoperative therapy. The absolute change or percentage change of those biomarkers will also be calculated and compared between the 2 arms using the nonparametric Mann-Whitney U test. The correlation among biomarkers will be described by Pearson correlation coefficient with 95% confidence interval. The p-value will be adjusted by Benjamini-Hochberg procedure to control the false discovery rate. All adverse events experienced data will be described by summary statistics and will be assessed according to CTCAE version 5.0. Currently, the study has accrued 2 participants. After completing accrual, we will assess whether the tumor-immune milieu has undergone modulation, resulting in a more immunogenic environment. If an immunogenic effect is demonstrated, this will provide rationale for a future multi-center trial assessing the combination of letrozole, simvastatin, and immunotherapy. Citation Format: Ruth Sacks, Elizabeth Haas, Jade Jones, Manali Bhave, Keerthi Gogineni, Jane Meisel, Demetria Smith-Graziani, Suchi Pakkala, Sarah Friend, Cletus Arciero, Lauren Postlewait, Clara Farley, Cathy Graham, Toncred Styblo, Monica Rizzo, Rhonda Pickett, Nicholas Crasta, Lori Brown, Xiaoxian Li, Sunil Badve, Madhav Dhodapkar, Kevin Kalinsky. A Randomized Window of Opportunity Study of Preoperative Letrozole and Simvastatin Versus Letrozole Alone in Stage I-III Hormone Receptor Positive, HER2 Negative Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-20-04.

A Practical Review of Encorafenib and Binimetinib Therapy Management in Patients with BRAF V600E-Mutant Metastatic Non-Small Cell Lung Cancer.

According to current guidelines, targeted therapy with a combination of BRAF plus MEK inhibitors is the preferred first-line treatment for patients with BRAF V600E-mutant metastatic non-small cell lung cancer (NSCLC). In the open-label, single-arm, phase2 PHAROS trial (NCT03915951), the combination of encorafenib, a potent BRAF inhibitor, and binimetinib, a potent MEK inhibitor, demonstrated durable antitumor activity with a manageable safety profile in this patient population. On the basis of the results of this study, the combination of encorafenib plus binimetinib was approved by the US Food and Drug Administration on October 11, 2023, for patients with BRAF V600E-mutant metastatic NSCLC. In this review, we summarize the efficacy and safety of encorafenib plus binimetinib from the PHAROS study. In addition, we discuss strategies to manage adverse reactions with this combination therapy with the intent of minimizing unnecessary treatment discontinuations in these patients.

Abstract PO2-14-06: CIRCULATING TUMOR DNA DYNAMICS IN THE FIRST TREATMENT LINE OF THE SONIA TRIAL

Abstract Background and objective: CDK4/6 inhibitors (CDK4/6i) improve the outcome of patients with ER+/HER2- advanced breast cancer when added to endocrine therapy in the first line or second line of treatment. The recently reported SONIA trial shows no difference in progression free survival after two lines of treatment (PFS2), overall survival (OS) or quality of life benefit of CDK4/6i in first-line compared to second-line, while adverse events are substantially higher when CDK4/6i is added in the first-line. However, a subgroup of patients shows early progression on endocrine mono-treatment and not all patients respond equally well to CDK4/6i. This highlights the need for early response markers during the first weeks of treatment to reduce unnecessary toxicity while providing the most optimal care. In this SONIA side study, we aim to investigate whether we could identify patients who will progress rapidly during first line of therapy by using circulating tumor DNA (ctDNA) dynamics. Methods: Blood samples were obtained from patients included in the SONIA trial in both the first line CDK4/6i + aromatase inhibitor (AI) combination arm (arm A) and the first line AI monotherapy arm (arm B) at three time points: before start, after two weeks and after three months of first line treatment. Cell free DNA (cfDNA) was isolated from all samples and subsequently baseline cfDNA was sequenced with the Oncomine™ Breast cfDNA Assay v2 (Thermofisher), a focused NGS panel of 10 genes. Dedicated dPCR assays were used to track an identified driver mutation over time. Results: Blood samples of 332 patients (206 in arm A and 126 in arm B) before start of first line treatment and after two weeks of treatment were obtained. At baseline, in 142 of the 332 (42.7%) patients at least one somatic mutation was detected. In 30 patients two or more mutations were identified, in which case the mutation with the highest variant allele frequency (VAF) was followed over time. The most frequently mutated genes were PIK3CA (102 patients (30.7% of the total included cohort)), TP53 (32 patients (9.6%)), SF3B1 (8 patients (2.4%) and ESR1 (6 patients (1.8%)). The median observed VAF at baseline was 4.1% (IQR: 1.5%-13.1%). Of the 142 patients with detectable ctDNA at baseline, 141 patients and 100 patients, respectively, had blood samples taken after 2 weeks and after 3 months of treatment. After two weeks, the VAF of the tracked mutation was increased in 15.2% (14/92) of the patients in arm A and in 18.4% (9/49) of the patients in arm B. At the same time 40.2% (37/92) of the patients in arm A and 34.7% (17/49) of the patients in arm B had cleared ctDNA. No difference was observed between the arms for both an increase in VAF (P=0.63, Chi-square test) and ctDNA clearance (P=0.52, Chi-square test). After 3 months an increased VAF of the tracked mutation compared to baseline was observed in 6.3% (4/64) of the patients in arm A and 8.3% (3/36) of the patients in arm B. At this timepoint 59.4% (38/64) of the patients in arm A and 61.1% (22/36) of the patients in arm B had cleared ctDNA. No difference was observed between the arms for both ctDNA clearance (P=0.86, Chi-square test) and increase in VAF (P=0.70, Chi-square test) after three months. Conclusions: ctDNA was detected at baseline in almost half of the patients in the SONIA study. Compared to baseline, a decreasing number of patients had an elevation of the VAF of the tracked mutation and an increasing number of patients showed ctDNA clearance from 2 weeks to 3 months after start of treatment. There was no difference between the two arms observed regarding ctDNA dynamics. Interestingly, irrespective of treatment arm, about 1/3rd of patients remained ctDNA-positive even after 3 months of treatment. Associations of these ctDNA data with the clinical outcome data are currently being evaluated and will be presented at the meeting. Citation Format: Elisabeth M Jongbloed, Stefania Stella, Lotte van Bergen, Corine Beaufort, Jean Helmijr, Vanja de Weerd, Frans Erdkamp, Joan Heijns, Yvonne Kamm, Anne-Marie van Riel, Quirine van Rossum-Schornagel, Maurice Jansen, Inge RHM Konings, Gabe Sonke, John WM Martens, Agnes Jager, Saskia M Wilting. CIRCULATING TUMOR DNA DYNAMICS IN THE FIRST TREATMENT LINE OF THE SONIA TRIAL [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-14-06.

Abstract PO2-27-05: Composite biomarkers for the prediction of progression-free survival with CDK4/6 inhibitors in metastatic HR+/HER2- breast cancer

Abstract CDK4/6 inhibitors are widely used in combination with endocrine therapy in the treatment of HR+/HER2- metastatic breast cancer. Generally the CDK4/6 inhibitors lead to a doubling of progression-free survival (PFS) over single agent endocrine therapy. In spite of a known mechanism of action, biomarkers to define the duration of response to CDK4/6 inhibitors with either aromatase inhibitors (AI) or fulvestrant (FUL) remain lacking. A cohort of over 300 patients receiving standard of care CDK4/6 inhibitor combination therapy for metastatic disease were consented for participation (NCT04526587). The duration of PFS in both AI and FUL treated sub-groups were comparable to that observed in randomized clinical trials. In this cohort progesterone receptor-status (HR 0.70, p=0.0123), visceral disease (HR 1.55, p=0.0013), prior endocrine therapy (HR 2.34, p< 0.001), and type of endocrine therapy (HR 2.16, p< 0.001) were associated with duration of PFS. To develop biomarkers, gene expression analyses was performed on 313 tumor samples representing over 200 individual patients. Focusing on the pre-treatment metastatic biopsy, established signatures associated with prognosis in HR+/HER2- breast cancer were employed to determine association with response to combination therapy in the metastatic setting. Proliferation-associated signatures were associated with shorter PFS. For example, an established RB loss signature was associated with PFS in both AI (HR 1.9, p=0.009) and FUL (HR 2.8, p=0.007) treated patients. Clinically employed signatures (e.g. OncotypeDx and Mammaprint) harbored variable associations with outcomes. Random Survival Forest feature selection was applied to individual and combined prognostic signatures. This approach resulted in a potent classifier for progression-free survival (HR 10, p< 1E-20). To enable applicability to different manifestations of disease, significant clinical pathological variables were incorporated into the model so that there was equivalent performance in AI and FUL treated patients for prediction of PFS. This predictive algorithm was also strongly associated with overall survival (HR 4.6, p=2.7E-8). Ongoing studies are evaluating the algorithms prospectively in NCT04526587. Citation Format: Agnieszka Witkiewicz, Jianxin Wang, Erik Knudsen, Ellis Levine, Tracey O'Connor. Composite biomarkers for the prediction of progression-free survival with CDK4/6 inhibitors in metastatic HR+/HER2- breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-27-05.

Abstract PS12-07: Phase II clinical trial of palbociclib and binimetinib in advanced triple-negative breast cancer (TNBC) with hyperactivation of ERK and/or CDK4/6

Abstract Background: We previously demonstrated that a kinase-based taxonomy of TNBC was most parsimonious than next-generation sequencing in defining TNBC subtypes associated with prognostic categories in early disease. The most aggressive TNBC variants were driven by a heterogeneous set of genetic aberrations that converged in the increased activity of 6 kinases: KIT, PNKP, PRKCE, P70S6K, ERK and CDK6 (Nat Commun; 9:3501-18). The combined inhibition of these kinases in pairs led to potent tumor regression in preclinical models, being the most powerful combination that one directed against CDK6 and ERK. This prompted us to design a phase II trial testing the combination of palbociclib (against CDK6) and binimetinib (against the ERK upstream kinase MEK, since no ERK inhibitor was available at that moment outside phase I trials) in advanced TNBC. Hyperactivation of CDK6 and/or ERK was selected as entry criterion. Trial design: This was a single-arm, prospective, multicentric, open-label, phase II investigator-initiated trial. CDK6 and phosphor-ERK levels were measured in tumor samples by immunohistochemistry and normalized with a reference sample collection to a Z-score. Patients with scores for either kinase above the median were candidates for the trial. Key inclusion criteria included metastatic >18year-old TNBC, adequate organ function, measurable disease, and progression to 1-2 prior treatment lines (including immunotherapy, and a PARP inhibitor in case of germline BRCA1/2 mutation). Patients started continuous oral binimetinib at 45 mg/BID and palbociclib 100 mg/day from days 1 to 21, in 28-day cycles. Patients experiencing ≤ grade 1 tolerable side effects as the greatest toxicity were escalated to palbociclib to 125 in cycle 2. RECIST 1.1 and NCI CTC AE V 5.0 were used for assessing disease control (q8 weeks) and toxicity. The primary aims were to assess the efficacy and toxicity of this combination, and the secondary one to detect biomarkers of activity. At the time of trial design, in absence of available Sacituzumab for prescription, the reference PFS to beat in advanced lines for physician’s choice in TNBC was 1.7 month (NEJM; 384:1529-41, 2021). With alpha and beta errors of 0.05 and 0.2, the minimum number of patients to demonstrate a 30% improvement in PFS to 2.5 months was 25. Results: From November 2020 to April 2023, 69 patients were screened and 24 entered the trial (5 positive for phosphor-ERK; 2 for CDK6; 17 for both). Toxicity was generally mild and included grade 1-2 diarrhea (33% of the patients), grade 1-2 asthenia (50%), grade 1-3 neutropenia (75%), grade 2 retinal toxicity (8.3%) and grade 3 rash (4.2%); no grade 4/5 toxicities were observed. Median PFS was 1.83 months (range 0.3 to 11.3+). Phospho-ERK and CDK6 levels were not correlated (Pearson’s R= -0.089; P=0.68); CDK6 levels did not show association with PFS time (R = -0.120; P=0.58). Interestingly, however, phosphor-ERK levels in the baseline tumor sample showed correlation with PFS time (R = 0.428; P=0.037). Conclusion: The combination of palbociclib and binimetinib was generally safe, and PFS time showed correlation with baseline phosphorylation levels of ERK. However, the trial did not meet its primary endpoint. Citation Format: Rodrigo Sánchez-Bayona, Alfonso Cortes, Juan Miguel Cejalvo, Luis Manso, Serafin Morales, Jose A Garcia-Saenz, Jorge Silva, Juan A Guerra, Diego Malón-Giménez, Silvana Mouron, Eduardo Caleiras, Miguel Quintela-Fandino. Phase II clinical trial of palbociclib and binimetinib in advanced triple-negative breast cancer (TNBC) with hyperactivation of ERK and/or CDK4/6 [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS12-07.

Combined in vivo effect of N-acylethanolamine-hydrolyzing acid amidase and glycogen synthase kinase-3β inhibition to treat multiple sclerosis

The current pharmacological approaches to multiple sclerosis (MS) target its inflammatory and autoimmune components, but effective treatments to foster remyelination and axonal repair are still lacking. We therefore selected two targets known to be involved in MS pathogenesis: N-acylethanolamine-hydrolyzing acid amidase (NAAA) and glycogen synthase kinase-3β (GSK-3β). We tested whether inhibiting these targets exerted a therapeutic effect against experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The combined inhibition of NAAA and GSK-3β by two selected small-molecule compounds, ARN16186 (an NAAA inhibitor) and AF3581 (a GSK-3β inhibitor), effectively mitigated disease progression, rescuing the animals from paralysis and preventing a worsening of the pathology. The complementary activity of the two inhibitors reduced the infiltration of immune cells into the spinal cord and led to the formation of thin myelin sheaths around the axons post-demyelination. Specifically, the inhibition of NAAA and GSK-3β modulated the over-activation of NF-kB and STAT3 transcription factors in the EAE-affected mice and induced the nuclear translocation of β-catenin, reducing the inflammatory insult and promoting the remyelination process. Overall, this work demonstrates that the dual-targeting of key aspects responsible for MS progression could be an innovative pharmacological approach to tackle the pathology.

Evaluation of the activity of cefepime/enmetazobactam against Enterobacterales bacteria collected in Europe from 2019 to 2021, including third-generation cephalosporin-resistant isolates.

ObjectivesThis study was performed to investigate the activity of the novel ß-lactam/ß-lactamase inhibitor combination cefepime/enmetazobactam, against recently circulating Enterobacterales isolates from Europe in 2019 to 2021. MethodsA total of 2,627 isolates were collected and antimicrobial susceptibility determined according to EUCAST guidelines. Isolates with phenotypic resistance to ceftriaxone and ceftazidime (but susceptible to meropenem), and isolates non-susceptible to meropenem were screened for the presence of ß-lactamases. ResultsOverall, susceptibility to third-generation cephalosporins was 77%, and 97.3% were susceptible to meropenem. Cefepime/enmetazobactam susceptibility was 97.9% (72% of these isolates were Klebsiella pneumoniae from Italy), compared to 80.0% susceptibility to piperacillin/tazobactam and 99.4% to ceftazidime/avibactam. A total of 320 isolates (12.2%) were resistant to third-generation cephalosporins but susceptible to meropenem and virtually all (96.3%) carried an ESBL with or without an AmpC and these were all susceptible to cefepime/enmetazobactam. Most meropenem-non-susceptible isolates carried a KPC (68%) which were not inhibited by cefepime/enmetazobactam but were inhibited by ceftazidime/avibactam. Most meropenem-non-susceptible isolates carrying OXA-48 (9/12 isolates) were susceptible to cefepime/enmetazobactam. ConclusionCefepime/enmetazobactam was highly active against Enterobacterales isolates, especially those resistant to third-generation cephalosporins. These data suggest that cefepime/enmetazobactam could be used as a carbapenem sparing agent to replace piperacillin/tazobactam.

Clinical Characteristics, Prognosis and Treatment of Bloodstream Infections with Enterobacter Cloacae Complex in a Chinese Tertiary Hospital: A Retrospective Study.

This research aimed to analyze the clinical characteristics, prognosis, and antimicrobial treatment of bloodstream infections (BSI) caused by Enterobacter cloacae complex (ECC). The clinical data of patients with bloodstream infections caused by Enterobacter cloacae complex from April 2017 to June 2023 were collected retrospectively. These data were then analyzed in subgroups based on the detection results of extended-spectrum β-lactamase (ESBL), 30-day mortality, and the type of antimicrobial agent used (β-lactam/β-lactamase inhibitor combinations (BLICs) or carbapenems). The proportion of ESBL-producing Enterobacter cloacae complex was 32.5% (37/114). Meanwhile, ICU admission, receiving surgical treatment within 3 months, and biliary tract infection were identified as risk factors for ESBL-producing ECC-BSI. Additionally, immunocompromised status and Sequential Organ Failure Assessment (SOFA) score ≥ 6.0 were identified as independent risk factors of 30-day mortality in patients with ECC-BSI (n = 108). Further analysis in BSI patients caused by non-ESBL-producing ECC revealed that patients treated with BLICs (n = 45) had lower SOFA scores and lower incidence of hypoproteinemia and sepsis compared with patients treated with carbapenems (n = 20). Moreover, in non-ESBL-producing ECC-BSI patients, the univariate Cox regression analysis indicated a significantly lower 30-day mortality rate in patients treated with BLICs compared to those treated with carbapenems (hazard ratios (HR) [95% CI] 0.190 [0.055-0.662], P = 0.009; adjusted HR [95% CI] 0.106 [0.013-0.863], P = 0.036). This study investigated the factors influencing the susceptibility to infection by ESBL-producing strains and risk factors for 30-day mortality in ECC-BSI patients. The results revealed that ESBL-negative ECC-BSI patients treated with BLICs exhibited significantly lower 30-day mortality compared to those treated with carbapenems. BLICs were found to be more effective in ECC-BSI patients with milder disease (ESBL-negative and SOFA ≤6.0).

Transcription factor EHF drives cholangiocarcinoma development through transcriptional activation of glioma-associated oncogene homolog 1 and chemokine CCL2.

Cholangiocarcinoma (CCA) is characterized by rapid onset and high chance of metastasis. Therefore, identification of novel therapeutic targets is imperative. E26 transformation-specific homologous factor (EHF), a member of the E26 transformation-specific transcription factor family, plays a pivotal role in epithelial cell differentiation and cancer progression. However, its precise role in CCA remains unclear. In this study, through in vitro and in vivo experiments, we demonstrated that EHF plays a profound role in promoting CCA by transcriptional activation of glioma-associated oncogene homolog 1 (GLI1). Moreover, EHF significantly recruited and activated tumor-associated macrophages (TAMs) through the C-C motif chemokine 2/C-C chemokine receptor type 2 (CCL2/CCR2) axis, thereby remodeling the tumor microenvironment. In human CCA tissues, EHF expression was positively correlated with GLI1 and CCL2 expression, and patients with co-expression of EHF/GLI1 or EHF/CCL2 had the most adverse prognosis. Furthermore, the combination of the GLI1 inhibitor, GANT58, and CCR2 inhibitor, INCB3344, substantially reduced the occurrence of EHF-mediated CCA. In summary, our findings suggest that EHF is a potential prognostic biomarker for patients with CCA, while also advocating the therapeutic approach of combined targeting of GLI1 and CCL2/CCR2-TAMs to inhibit EHF-driven CCA development.

Comparative efficacy of immune checkpoint inhibitors combined with chemotherapy in patients with advanced driver-gene negative non-small cell lung cancer: A systematic review and network meta-analysis

ObjectiveTo evaluate the efficacy of different combinations of immune checkpoint inhibitors (ICIs) and chemotherapy (CT) in the treatment of advanced non-small cell lung cancer (NSCLC). MethodsWe obtained relevant randomized controlled trials (RCTs) from databases such as PubMed, Embase, Web of Science, and The Cochrane Library up to May 31, 2023. The analysis of clinical prognostic factors was performed using R 4.2.3 and STATA 15.0. The main outcomes measured were overall survival (OS) and progression-free survival (PFS), while secondary outcomes included the objective response rate (ORR), disease control rate (DCR), and treatment-related adverse events of grade 3–5 severity (Grade ≥3 TRAE). ResultsA total of 17 randomized controlled trials (RCTs) were conducted between 2012 and 2023, involving 7792 patients. These trials evaluated 11 different treatment methods. The results of these trials showed that in terms of overall survival (OS) and progression-free survival (PFS), the combination of tislelizumab with chemotherapy and the combination of camrelizumab with chemotherapy were particularly effective. Moreover, when compared with other combination therapies, pembrolizumab combined with chemotherapy showed superiority in terms of disease control rate (DCR) and objective response rate (ORR). Subgroup analyses further demonstrated that the addition of immune checkpoint inhibitors (ICIs) to chemotherapy significantly improved PFS and OS in patients without liver metastasis and in those with brain metastasis. Additionally, carboplatin-based combination therapy was found to confer favorable survival benefits in terms of PFS, while cisplatin-based combination therapy showed the most favorable outcomes in terms of OS. The results of subgroup analyses for overall survival (OS) showed that the combination of immunotherapy and chemotherapy yielded positive outcomes in specific subgroups. These subgroups were characterized by PD-L1 Tumor Proportion Score (TPS) of 50 % or higher, usage of anti-PD-1 medications, age below 65, male gender, smoking history, and non-squamous cell carcinoma histology. Superior effectiveness was demonstrated only in extending the progression-free survival (PFS) of female patients and patients with squamous carcinoma. Meanwhile, other patient cohorts did not show the same level of improvement. ConclusionsTislelizumab, camrelizumab or pembrolizumab combined with chemotherapy may be the optimal first-line treatment strategies for NSCLC.

Emerging advances in delivery systems for mRNA cancer vaccines

The success of lipid nanoparticles (LNPs) in treating COVID-19 promotes further research of mRNA vaccines for cancer vaccination. Aiming at overcoming the constraints of currently available mRNA carriers, various alternative nano-vectors have been developed for delivering tumor antigen encoding mRNA and showed versatility to induce potent anti-tumor immunity. The rationally designed nano-vaccines increase the immune activation capacity of the mRNA vaccines by promoting crucial aspects including mRNA stability, cellular uptake, endosomal escape and targeting of immune cells or organs. Herein, we summarized the research progress of various mRNA based nano-vaccines that have been reported for cancer vaccination, including LNPs, lipid enveloped hybrid nanoparticles, polymeric nanoparticles etc. Several strategies that have been reported for further enhancing the immune stimulation efficacy of mRNA nano-vaccines, including developing nano-vaccines for co-delivering adjuvants, combination of immune checkpoint inhibitors, and optimizing the injection routes for boosting immune responses, have been reviewed. The progress of mRNA nano-vaccines in clinical trials and the prospect of the mRNA vaccines for cancer vaccination are also discussed.