Efficacy Of Platinum-based Chemotherapy Research Articles

Deleterious alterations in homologous recombination repair genes and efficacy of platinum-based chemotherapy in biliary tract cancers.

Platinum-based chemotherapy represents the standard first-line treatment for biliary tract cancers (BTC). Deficits in genes involved in the homologous recombination (HR) and DNA damage response (DDR) may confer higher sensitivity to platinum agents. We retrospectively included patients affected by BTC from 2 Italian institutions. Inclusion criteria consist of the receipt of platinum-based chemotherapy in the metastatic setting and the availability of comprehensive genomic profiling using next-generation sequencing (NGS). Patients were included in the HRD-like group if demonstrated oncogenic or likely oncogenic alterations in HR-/DDR-genes. Clinical endpoints were compared between the HRD-like group and the non-HRD-like group. Seventy-four patients were included, of whom 25 (33%) in the HRD-like group and 49 (66%) in the non-HRD group. With a median follow-up of 26.04 months (interquartile-range [IQR] 9.41-29.27) in the HRD-like group and of 22.48 months (IQR 16.86-40.53) in the non-HRD group, no PFS difference emerged, with a mPFS of 5.18 months in the HRD-like group compared to 6.04 months in the non-HRD group (hazard ratio [HR], 1.017, 95% CI 0.58-1.78; P = .95). No differences were observed in DCR (64% [95 CI 45%-83%] vs 73% [95 CI 61%-86%]; P = .4), and CBR (45% [95% CI 28%-73%] vs 50% [95% CI, 37%-68%]; P = .9) between the HRD-like group and non-HRD groups, respectively. Median OS did not statistically differ between the HRD-like group and non-HRD group (26.7 vs 18.0 months, respectively; HR, 0.670, 0.33 to 1.37, P = .27). HR-/DDR-genes, when assessed with regular tumor-only NGS panels, provide limited clinical validity to identify patients with BTC more likely to benefit from platinum-based chemotherapy.

RAD51 Expression as a Biomarker to Predict Efficacy of Platinum-Based Chemotherapy and PD-L1 Blockade for Muscle-Invasive Bladder Cancer.

RAD51, a key recombinase that catalyzes homologous recombination (HR), is commonly overexpressed in multiple cancers. It is curial for DNA damage repair (DDR) to maintain genomic integrity which could further determine the therapeutic response. Herein, we attempt to explore the clinical value of RAD51 in therapeutic guidance in muscle-invasive bladder cancer (MIBC). In this retrospective study, a total of 823 patients with MIBC were included. Zhongshan hospital (ZSHS) cohort (n=134) and The Cancer Genome Atlas-Bladder Cancer (TCGA-BLCA) cohort (n=391) were included for the investigation of chemotherapeutic response. The IMvigor210 cohort (n=298) was utilized to interrogate the predictive efficacy of RAD51 status to programmed cell death ligand-1 (PD-L1) blockade. In addition, the association of RAD51 with genomic instability and tumor immune contexture was investigated. Patients with RAD51 overexpression were more likely to benefit from both platinum-based chemotherapy and immunotherapy rather than RAD51-low patients. The TMBhighPD-L1highRAD51high subgroup possessed the best clinical benefits from PD-L1 blockade. RAD51-high tumors featured by genomic instability were correlated to highly inflamed and immunogenic contexture with activated immunotherapeutic pathway in MIBC. RAD51 could serve as a prognosticator for treatment response to platinum-based chemotherapy and PD-L1 inhibitor in MIBC patients. Besides, it could also improve the predictive efficacy of TMB and PD-L1.

Comprehensive Genomic Characterization in Ovarian Low-Grade and Chemosensitive and Chemoresistant High-Grade Serous Carcinomas

Introduction: Genomic characterization of serous ovarian carcinoma (SOC), which includes low-grade serous carcinoma (LGSC) and high-grade serous carcinoma (HGSC), remains necessary to improve efficacy of platinum-based chemotherapy. The aim of this study was to investigate the genomic variations in these SOC groups, also in relation to chemoresponse. Methods: Forty-five samples of SOC were retrospectively analyzed by next-generation sequencing on DNA/RNA extracts from formalin-fixed, paraffin-embedded (FFPE) tumor samples obtained at diagnosis. HGSCs were classified as platinum-resistant and platinum-sensitive. Results: In the LGSC group, 44% of the carcinomas had mutually exclusive variants in the RAS/RAF pathway, while additional likely oncogenic variants in the CDKN2A, SMARCA4, and YAP1 genes were observed in the remaining LGSCs. Tumor mutation burden (TMB) was significantly lower in the intrinsically chemoresistant LGSC group than in the HGSC group. In the HGSC cohort, TP53 variants were found in 90% and homologous recombination repair (HRR) pathway variants in 41% of the neoplasms. HGSCs of the chemoresistant group without classic mutations in the HRR pathway were characterized by additional variants in FGFR2 and with an FGFR3::TACC3 fusion. In addition, HGSCs showed MYC, CCNE1, and AKT2 gains that were almost exclusively observed in the chemosensitive HGSC group. Conclusion: These results suggest that very low TMB and MYC, CCNE1, and AKT2 gains in SOC patients may be biomarkers related to platinum treatment efficacy. Thorough genomic characterization of SOCs prior to treatment might lead to more specific platinum-based chemotherapy strategies.

Efficacy of Platinum-based Chemotherapy in Patients With Metastatic Urothelial Carcinoma With Variant Histology.

Variant urothelial carcinoma (VUC, defined herein as urothelial carcinoma with any histological variant) is frequently observed at an advanced stage. However, the efficacy of systemic chemotherapy against VUC in metastatic disease has rarely been reported. This study assessed the therapeutic response and survival outcomes of platinum-based chemotherapy as first-line treatment in patients with metastatic VUC. We retrospectively analyzed consecutive patients with metastatic bladder and upper urinary tract cancer who received gemcitabine plus cisplatin (or carboplatin) at the University of Occupational and Environmental Health Hospital between November 2008 and November 2022. Progression-free survival and overall survival were evaluated using the Kaplan-Meier method and Cox proportional hazard models. Out of 131 patients recorded, 86 (65.6%) had pure urothelial carcinoma (PUC) and 45 (34.4%) had VUC. The most common variant element was squamous differentiation (44.4%). Compared to those with PUC, patients with VUC showed a comparable objective response rate (33.3% vs. 41.9%, p=0.451) and disease control rate (64.5% vs. 75.6%, p=0.221). They also had poorer progression-free survival (median=4.9 months vs. 7.9 months, p=0.014) and overall survival (median=10.9 months vs. 18.2 months, p=0.037) than those with PUC. On multivariate analysis, VUC was an independent predictor of progression (hazard ratio=1.79; 95% confidence interval=1.19-2.69; p=0.005) and mortality (hazard ratio=1.64; 95% confidence interval=1.08-2.48; p=0.020). Although the response of metastatic VUC to platinum-based chemotherapy was not inferior to that of PUC, VUC had progressed faster than PUC. VUC was significantly associated with a poor prognosis after platinum-based chemotherapy as first-line treatment.

Cisplatin-activated ERβ/DCAF8 positive feedback loop induces chemoresistance in non-small cell lung cancer via PTEN/Akt axis

High levels of the estrogen receptor β (ERβ) predict poor prognosis following platinum-containing adjuvant chemotherapies in patients with non-small cell lung cancer (NSCLC). However, the precise role of ERβ remains elusive. In this study, we demonstrated that targeting ERβ could significantly increase the cytotoxicity of cisplatin both in vitro and in vivo. Mechanically, cisplatin directly binds to ERβ, which facilitates its homodimerization and nuclear translocation. ERβ activation transcriptionally represses the expression of DCAF8, an adaptor of CRL4 E3 ubiquitin ligase, which in turn attenuates the proteasomal degradation of ERβ, leading to ERβ accumulation; this positive feedback loop results in Akt activation and eventually cisplatin resistance in NSCLC through PTEN inhibition. Moreover, low expression of DCAF8 and high expression of ERβ are associated with treatment resistance in patients receiving cisplatin-containing adjuvant chemotherapy. The present results provide insights into the underlying mechanism of ERβ-induced cisplatin resistance and offer an alternative therapeutic strategy to improve the efficacy of platinum-based chemotherapy in patients with NSCLC.

The Relationship between Single Nucleotide Polymorphism of ERCC1 Gene and the Response to Platinum Based Chemotherapy in Egyptian Non-Small Cell Lung Cancer Patients

Abstract Background Lung cancer (LC) is the second most common cancer diagnosed in both males and females. There are two subtypes of LC. Non-small cell lung cancer (NSCLC) is the major one. Treatment options for NSCLC depends mainly on the stage at diagnosis. The majority of the patients are diagnosed at advanced stages at time of presentation. Therefore, chemotherapy and radiotherapy play the dominant role in treatment of advanced NSCLC. The most commonly used chemotherapy is platinum-based chemotherapy as cisplatin and carboplatin and third generation drugs as vinorelbine and gemcitabine. The efficacy of platinum-based chemotherapy is limited by chemoresistance. The excision repair cross complementation group 1(ERCC1) gene is a member of nucleotide excision repair pathway that plays a critical role in the DNA repair by removing DNA covalent helix-distorting adducts. Aim of the Work In this study investigated the relationship between single nucleotide polymorphism of ERCC1 rs11615 and the response to platinum-based chemotherapy in Egyptian NSCLC patients in order to prevent the non-necessary exposure to the toxic effect of chemotherapy. Patients and Methods This is a cross-sectional study conducted on 50 NSCLC patients who were recruited from the Oncology Clinic in Ain Shams University Hospitals; twenty of them were responders to platinumbased chemotherapy and the other 30 were non-responders according to RECIST criteria. All subjects underwent full medical history focusing on tobacco smoking and family history of cancers, thorough clinical examination, histological diagnosis of NSCLC and TNM classification, radiological studies: computed tomography of chest and abdomen and laboratory investigations in the form of: complete blood picture (CBC), liver function tests and kidney function tests. Detection of the ERCC1 (T/C) polymorphism by realtime PCR was done for both the responders' and the non-responders' groups. Results There was no significant statistical difference observed between the responders’ and nonresponders’ groups regarding the genotype frequencies nor the allelic frequency (p > 0.05). Conclusion The present study did not confirm the presence of significant association between the genotypic frequencies nor the allelic frequencies of the ERCC1 rs 11615 among the responders' and the non-responders' groups. Further studies with higher sample size are needed to clarify the association.

Association of Glutathione S-Transferase P1 (GSTP1) Gene Polymorphism with the Response to Platinum Based Chemotherapy in Patients with Non-Small Cell Lung Cancer

Abstract Background Lung cancer is one of the most commonly diagnosed cancers and despite therapeutic advances, mortality remains high. Platinum based chemotherapy remains the mainstay of adjuvant or first line chemotherapy in non small cell lung cancer (NSCLC) treatment, pathophysiological features along with genetic background significantly influence therapeutic efficacy of platinum-based chemotherapy. GSTP1 gene is a member of the cytosolic superfamily of glutathione-S-transferases, which is responsible for phase II detoxification enzymes that convert various reactive metabolites to more water-soluble and less harmful forms by conjugating them with glutathione. The genetic polymorphism GSTP1 rs1695 is associated with decreased substrate specific catalytic activity and the reduced enzyme activity which may reduces platinum detoxification, thus promoting better response rates to platinum-based chemotherapy. Aim of the Work In the present study was aimed to investigate the association of GSTP1 gene polymorphism with the response to platinum based chemotherapy in patients with NSCLC in order to prevent the non necessary exposure to the toxic effect of chemotherapy. Patients and Methods The study was a retrospective cross sectional study conducted on 50 NSCLC patients who were recruited from the Oncology clinic in Ain Shams University Hospitals, twenty of them were responders to platinum based chemotherapy and the other 30 were not responders according to RECIST criteria. All subjects underwent full medical history focusing on tobacco smoking and family history of cancers, thorough clinical examination, histological diagnosis of NSCLC and TNM classification, radiological studies: computed tomography of chest and abdomen and laboratory investigations in the form of: complete blood picture (CBC), liver function tests and kidney function tests. Detection of the GSTP1 rs1695 (A/G) polymorphism by real-time PCR was done for both the responders and the non responders group. Results There was no statistically significant difference between the responders’ and non responders’ groups regarding the genotypic distribution (p > 0.05). However, the G allele was significantly higher in the responders’ group compared to the non responders’ group with p value < 0.05. Conclusion The present study did not confirm the presence of significant association between the genotypic frequencies of the GSTP1 rs 1695 among the responders and the non responders group, but despite that it showed that the A allele was significantly higher in the non responders’ group compared to the responders’ group. However, the G allele was significantly higher in the responders’ group compared to the non responders’ group. Further studies with higher sample size are needed to clarify the association.

Mutations in the DNA polymerase binding pathway affect the immune microenvironment of patients with small-cell lung cancer and enhance the efficacy of platinum-based chemotherapy.

Small-cell lung cancer (SCLC) is characterized by its high malignancy and is associated with a poor prognosis. In the early stages of the disease, platinum-based chemotherapy is the recommended first-line treatment and has demonstrated efficacy. However, SCLC is prone to recurrence and is generally resistant to chemotherapy in its later stages. Here, we collected samples from SCLC patients who received platinum-based chemotherapy, performed genomic and transcriptomic analyses, and validated our results with publicly available data. SCLC patients with DNA polymerase binding pathway mutations had an improved prognosis after platinum chemotherapy compared with patients without such mutations. Patients in the mutant (MT) group had higher infiltration of T cells, B cells, and M1 macrophages compared with patients without DNA polymerase binding pathway mutations. DNA polymerase binding pathway mutations can be used as prognostic markers for platinum-based chemotherapy in SCLC.

The clinical value of homologous recombination deficiency score in prostate cancer.

e17011 Background: Aberrations in homologous recombination repair (HRR) genes serve as biomarkers for guiding the treatment decision of PARP inhibitors in prostate cancer (PCa). Homologous recombination deficiency (HRD) score which directly shows the consequence of the loss of HRR function (genomic scars) may be a more reliable biomarker for identifying patients who are sensitive to PARP inhibitors. Methods: This study involved 50 patients with PCa, including mHSPC (n = 37), mCRPC (n = 11), and locally advanced PCa (n = 2). Tumor tissue specimens were collected for targeted next-generation sequencing for 406 cancer-related genes and HRD detection. HRD score was calculated based on over 50,000 single-nucleotide polymorphisms (SNP) distributed across the human genome, incorporating three SNP-based assays: loss of heterozygosity, telomeric allelic imbalance, and large-scale state transition. All the experiments were performed in OrigiMed, a College of American Pathologists accredited and Clinical Laboratory Improvement Amendments certified laboratory. Results: The median HRD score was 34.5 (ranged from 14 to 64). With the median value as cutoff, the mutation rates of HRR were 32% (8/25) and 12% (3/25) in the high and low HRD score groups, respectively. BRCA2 mutations (P = 0.011), AR mutations (P = 0.032), RB1 mutations (P = 0.035) and altered HRR pathway (P = 0.017) were associated with high HRD scores. The mutation frequencies of AR and TP53 were significantly higher in mCRPC compared to mHSPC ( AR: 45.5% [5/11] vs 2.7% [1/37], P < 0.001; TP53: 63.6% [7/11] vs 24.3% [9/37], P = 0.027). A total of 9 patients carried HRR germline mutations (5 BRCA2, 1 BRIP1, 1 RAD50, 1 RAD51D, and 1 ATM). It was found that patients with BRCA2 germline mutations had a higher HRD score (median = 37) than those with other germline mutations ( BRIP1: 25, RAD50: 19, RAD51D: 35, ATM: 36). In the 6 patients who received HRD-related treatments (including cisplatin based chemotherapy or olaparib), 1 of the 2 patients with low HRD score had PSA progression after 251 days (the other one was lost to follow up), while no PSA progression was observed in the 4 patients with high HRD score with a median follow-up of 107 days (range: 40-274 days). A mCRPC case with high HRD score (37) and HRR wild-type who received second line docetaxel+cisplatin even achieved undetectable PSA. Another mHSPC patient with a high HRD score (37) and a BRCA2 germline mutation also had no detectable PSA after first-line docetaxel+cisplatin therapy. Conclusions: To our knowledge, this is the first study in China reporting the association of HRD score and platinum-based treatments in PCa. Our results supported the possibility that HRD score could be predictive for the efficacy of platinum-based chemotherapy.

The impact of DNA damage repair gene mutations on therapeutic response among Chinese patients diagnosed with advanced biliary tract cancer.

e16190 Background: Biliary tract cancer (BTC) is a fatal disease characterized by molecular heterogeneity, which results in variations in biological behavior. Despite this, the knowledge of pathogenic alterations in the Chinese BTC population using next-generation sequencing (NGS) profiles remains limited. Therefore, we performed a retrospective investigation to assess the predictive significance of DNA damage repair (DDR) mutations in facilitating precision medicine for this disease. Methods: NGS profiling was carried out on resected tissues obtained from Chinese patients diagnosed with advanced BTC. In addition, baseline clinical and genetic characteristics were collected, along with data on their survival outcomes. Results: A total of 68 Chinese patients with BTC who received first-line platinum-containing chemotherapies were enrolled in this study [intrahepatic cholangiocarcinoma (ICC), 33; extrahepatic cholangiocarcinoma (ECC), 13; gallbladder carcinoma (GBC), 22]. Genetic alterations were observed in 67 patients (98.5%), with TP53 (50.0%), KRAS (26.8%), ARID1A (16.2%), and CDKN2A (16.2%) being the most commonly mutated genes. Patients with TP53 mutations demonstrated a trend towards reduced median OS (16.6 vs. 20.1 months, P=0.145). Mutations in DDR genes were identified in 29 (42.6%) of overall patients, primarily involving ATM (11.8%) and BAP1 genes (8.8%), and were significantly associated with longer mPFS (6.4 vs. 4.8 months, P=0.022) and mOS (21.2 vs. 14.3 months, P=0.011) in patients who received first-line platinum-containing chemotherapies. DDR-mutated patients treated with PD-1 blockades showed a tendency towards improved overall survival compared to the DDR-naive group (20.8 vs. 14.3 months, P=0.297). Furthermore, tumor mutational burden (TMB) could be estimated in 63 cases and was significantly higher in those with DDR mutations (P=0.029). Conclusions: Genetic information can aid in identifying a subgroup of BTC patients who may benefit from targeted therapy, this retrospective study demonstrated the predictive significance of DDR mutations for platinum-based chemotherapy efficacy in Chinese patients. Nonetheless, additional research is necessary to explore the potential of DDR mutations in predicting sensitivity to PD-1 blockade.

ROS-mediated SRMS activation confers platinum resistance in ovarian cancer.

Ovarian cancer is the leading cause of death among gynecological malignancies. Checkpoint blockade immunotherapy has so far only shown modest efficacy in ovarian cancer and platinum-based chemotherapy remains the front-line treatment. Development of platinum resistance is one of the most important factors contributing to ovarian cancer recurrence and mortality. Through kinome-wide synthetic lethal RNAi screening combined with unbiased datamining of cell line platinum response in CCLE and GDSC databases, here we report that Src-Related Kinase Lacking C-Terminal Regulatory Tyrosine And N-Terminal Myristylation Sites (SRMS), a non-receptor tyrosine kinase, is a novel negative regulator of MKK4-JNK signaling under platinum treatment and plays an important role in dictating platinum efficacy in ovarian cancer. Suppressing SRMS specifically sensitizes p53-deficient ovarian cancer cells to platinum in vitro and in vivo. Mechanistically, SRMS serves as a "sensor" for platinum-induced ROS. Platinum treatment-induced ROS activates SRMS, which inhibits MKK4 kinase activity by directly phosphorylating MKK4 at Y269 and Y307, and consequently attenuates MKK4-JNK activation. Suppressing SRMS leads to enhanced MKK4-JNK-mediated apoptosis by inhibiting MCL1 transcription, thereby boosting platinum efficacy. Importantly, through a "drug repurposing" strategy, we uncovered that PLX4720, a small molecular selective inhibitor of B-RafV600E, is a novel SRMS inhibitor that can potently boost platinum efficacy in ovarian cancer in vitro and in vivo. Therefore, targeting SRMS with PLX4720 holds the promise to improve the efficacy of platinum-based chemotherapy and overcome chemoresistance in ovarian cancer.

Abstract 5957: Chemotherapy-induced extracellular matrix remodeling in HGSOC

Abstract In this study we explored the effects of chemotherapy on the extracellular matrix of high-grade serous ovarian cancer metastasis (HGSOC) at structural-textural protein level and transcriptionally, in order to identify the microenvironmental features that accompany a successful response. We studied two murine orthotopic, transplantable syngeneic models of HGSOC, one that displays excellent response to carboplatin/paclitaxel (60577) and one that is resistant to treatment (HGS2)1. Using immunohistochemistry, we stained omental tumors from both models for the ECM components fibronectin (FN1), collagen 1A1 (COL1A1) and versican (VCAN), also using Masson’s Trichrome to stain for collagen. We analyzed their abundance, textural features (Haralick features) and structure with the image analysis softwares, QuPath and TWOMBLI respectively. A compilation of 44 ECM metrics, which we named the “structure index”, correlated with response to chemotherapy, as measured by reduction in omental tumor weight. In parallel, we performed RNAseq on the omental tumors, identifying clusters of genes that change over time with chemotherapy treatment of the responsive model 60577, while the chemoresistant model HGS2 displayed limited alteration of gene expression. We integrated RNAseq and ECM structure and texture data, and showed the structure index was correlated with 144 core matrisome genes. To identify potential therapeutic targets, we then focused our study on genes that remained highly expressed in resistant tumors post chemotherapy, but were originally low or decreased with treatment in the sensitive tumors. Members of the LOX and P4HA family were found amongst these genes. We confirmed by immunohistochemical analysis that expression of LOX, LOXL2, P4HA1 and P4HA2 was downregulated by chemotherapy in the 60577 chemo-sensitive tumors while their levels remained relatively unaffected in the resistant HGS2 tumors. This study refines our understanding of the mechanisms of microenvironmental chemoresistance in HGSOC, highlighting putative therapeutic targets to increase the efficacy of platinum-based chemotherapy in ovarian cancer. 1 Maniati, E. et al. Mouse Ovarian Cancer Models Recapitulate the Human Tumor Microenvironment and Patient Response to Treatment. Cell Rep 30, 525-540.e527, doi:10.1016/j.celrep.2019.12.034 (2020). Citation Format: Panoraia Kotantaki, Florian Laforêts, Eleni Maniati, Chiara Berlato, Anna Malliouri, Michael John Devlin, Beatrice Malacrida, Samar Elorbany, Ranjit Manchanda, Frances R. Balkwill. Chemotherapy-induced extracellular matrix remodeling in HGSOC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5957.

Abstract P6-01-09: Efficacy of platinum-based chemotherapy and germline mutational status in early-stage triple-negative breast cancer: a unicenter retrospective analysis with long-term follow-up

Abstract BACKGROUND: In early-stage triple negative breast cancer (TNBC), the addition of carboplatin (CBDCA) to neoadjuvant chemotherapy (CT) increases pathologic complete response (pCR) and relapsed-free survival. However, it is unclear whether CBDCA improves overall survival (OS). In addition, the prognostic and/or predictive role of pathogenic germline variants (PGV) in BRCA1/2 genes and other cancer risk in this setting is not fully understood. Here, we assessed the efficacy of (neo)adjuvant CBDCA and the prognostic and predictive role of a panel of 14 genes in patients (pts) with eTNBC. METHODS: This is a retrospective study on 117 pts diagnosed with early-stage TNBC between 2000-2021 at Hospital Clinic of Barcelona. Eighty-one pts (69%) were candidates for PGV testing. Overall, 14 genes (PGV) (BRCA1, BRCA2, PALB2, BRIP1, CHEK2, TP53, ATM, RAD51C, RAD51D, BARD1, MLH1, MSH2, MSH6 and PMS2) were assessed using the TruSight hereditary cancer panel (Illumina MySeq platform) according to local guidelines. Univariable and multivariable logistic regression and Cox regression analyses were performed to identify clinical and molecular predictors of pCR and relapse-free survival (RFS), respectively. Chi-squared or Fisher’s exact tests were used to assess characteristics’ distribution as appropriate. RESULTS: Of 117 pts, 83 (71%) received CT in the neoadjuvant setting and 28 (24%) in the adjuvant setting. CBDCA was added to standard CT in 68 pts (82%) in the neoadjuvant cohort and 7 pts (6%) in the adjuvant cohort. Among pts with germline testing, 32/81 (39%) harbored PGV. BRCA1 was the most frequently mutated gene (18/32, 56%), followed by BRCA2 (5/32, 16%), PALB2 (4/32, 13%), BRIP1 (2/32, 6%), CHEK2, TP53 and PMS2 (3/32, 6%). Percentages of pts receiving CBDCA were similar between patients with and without PGV (14/16,87% and wild type (53/67,79%)(p=0.120). In the neoadjuvant cohort (n=83), CBDCA was the only variable significantly associated with pCR at both univariate (pCR rates of 58.5% with CBCDA and 14.3% without CBCDA; odds ratio [OR]=8.2 [95% CIs 2.0-55.7], p=0.008) and remained statistically significant after adjusting for PGV, tumor size and nodal status (OR=6.9 [95% CIs 1.4-53.0], p=0.028). pCR rates according to PGV are reported in Table 1. In terms of RFS, addition of CBDCA to neoadjuvant therapy (hazard ratio [HR]=0.2 [0.1-0.45], p< 0.001), PGV (HR=0.2 [0.05-0.9], p=0.048), pCR (HR=0.2 [0.1-0.6], p=0.004) and nodal status (HR=5.1 [1.7-15.2], p< 0.003) were significantly associated with RFS in univariate analyses. In a multivariable model, CBDCA remained an independent predictor of improved RFS along with pCR. When the neoadjuvant and adjuvant cohort were pooled together (n=117), platinum-based CT remained significantly associated with better RFS (HR=0.2 [0.14-0.86], p=0.021) regardless of time of administration (i.e., neoadjuvant or adjuvant). With a median follow-up of 5 years, CBCDA use was not found associated with OS (HR=0.7 [0.3-1.8], p= 0.560). CONCLUSIONS: The addition of CBDCA to standard CT was significantly associated with pCR and RFS but not OS, consistent with the phase III data. The benefit in terms of RFS was independent of the presence and the type of pathogenic germline alterations. Table 1. pCR rates according to PGV Citation Format: Adela Rodríguez Hernández, Benedetta Conte, Laia Fernández, Fara Brasó-Maristany, Belén Pastor, Miriam Potrony, Lorena Moreno, Elia Grau, Joan Antón Puig-Butillé, Aurora Sánchez, Blanca González-Farré, Esther Sanfeliu, Olga Martínez-Sáez, Claudette Falato, Maria Vidal, Nuria Chic, Tomás Pascual, Francesco Schettini, Montserrat Muñoz, Francesc Balaguer, Aleix Prat, Barbara Adamo. Efficacy of platinum-based chemotherapy and germline mutational status in early-stage triple-negative breast cancer: a unicenter retrospective analysis with long-term follow-up [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-09.

Activation of the TGF-β Pathway Enhances the Efficacy of Platinum-Based Chemotherapy in Small Cell Lung Cancer Patients.

Platinum-based chemotherapy is the first choice of treatment for patients diagnosed with small lung cell cancer (SCLC). However, many patients exhibit resistance to it. Therefore, it is imperative to further investigate a prognostic biomarker indicating sensitivity to this therapy. We collected and performed RNA sequencing on 45 SCLC samples from the Zhujiang Hospital (Local-SCLC). In addition, we used a public cohort from George et al. as a validation cohort (George-SCLC). The transforming growth factor β signaling pathway (TGFB) activation status was determined according to the related ssGSEA score. We analyzed immune cell ratios, pathway activation scores, and immune-related genes in SCLC patients to further elucidate the potential mechanisms. A high activation status of the TGFB pathway was associated with improved prognosis in SCLC patients receiving platinum-based chemotherapy (Local-SCLC: HR = 0.0238, (95% CI, 0.13-0.84), p = 0.0238; George-SCLC: HR = 0.0315, (95% CI, 0.28-0.98), p = 0.0315). Immune infiltration analysis showed that the TGFB-HIGH group had more M1 macrophages and Th1 cells, whilst fewer M2 macrophages, Th2 cells, and Treg cells were found in the Local-SCLC cohort. Mechanistic analysis showed that the TGBF-HIGH group was upregulated in STING-mediated immunity, apoptosis, and cell cycle arrest, as well as being downregulated in the process of DNA damage repair. SCLC patients exhibiting a high activation status of the TGFB pathway demonstrate an improved prognosis with platinum-based chemotherapy. The potential underlying mechanism may be related to antitumor immune enhancement and DNA damage repair inhibition.

Next-generation sequencing of homologous recombination genes could predict efficacy of platinum-based chemotherapy in non-small cell lung cancer.

With the widespread use of next-generation sequencing (NGS) in clinical practice, an increasing number of biomarkers that predict a response to anti-tumor therapy in non-small cell lung cancer (NSCLC) has been identified. However, validated biomarkers that can be used to detect a response to platinum-based chemotherapy remain unavailable. Several studies have suggested that homologous recombination deficiency (HRD) may occur in response to platinum-based chemotherapy in ovarian cancer and breast cancer. However, currently there is a lack of proven and reliable HRD markers that can be used to screen for patients who may benefit from platinum-based chemotherapy, especially in NSCLC. NGS was used to screen for gene mutations, including homologous recombination (HR) genes and common driver gene mutations in NSCLC. Cox regression analysis was performed to identify potential clinicopathological or gene mutation factors associated with survival in patients receiving platinum-based chemotherapy, while Kaplan-Meier analysis with the log-rank test was performed to assess the effect of HR gene mutations on progression-free survival (PFS). In a retrospective cohort of 129 patients with advanced NSCLC, 54 who received platinum-based chemotherapy with or without anti-angiogenic therapy were included in the analysis. Univariate and multivariate Cox proportional hazard regression analyses showed that HR gene mutations were associated with platinum-based chemotherapy sensitivity. Efficacy results indicated that the objective response rates (ORR) for patients with BRCA1/2 mutations and BRCA1/2 wild type were 75% and 30.4% (p=0.041), while the median PFS was 7.5 and 5.5 months (hazard ratio [HR], 0.52; 95% CI, 0.27-1.00; p=0.084), respectively. The ORRs of patients with HR gene mutations and HR gene wild type were 60% and 23.6% (p=0.01), and the median PFS was 7.5 and 5.2 months (HR, 0.56; 95% CI, 0.32-0.97; p=0.033), respectively. HR gene mutations show potential as promising biomarkers that may predict sensitivity to platinum-based chemotherapy in advanced and metastatic NSCLC.

PP112 The efficacy of platinum-based chemotherapy and biomarkers in triple-negative breast cancer

PP112 The efficacy of platinum-based chemotherapy and biomarkers in triple-negative breast cancer

DNA damage repair gene mutations predict the efficacy of platinum-based chemotherapy and immunotherapy plus platinum-based chemotherapy in advanced non-small cell lung cancer: a retrospective Chinese cohort study

Platinum-based chemotherapy (PC) and immunotherapy plus platinum-based chemotherapy (IPC) remain the first-line treatment for advanced NSCLC. But only a minority patients benefit from PC, and existing biomarkers, such as PD-L1, have been shown to be defective in predicting the efficacy of IPC. Highlighting the need to identify novel biomarkers for the efficacy of PC and IPC. DNA damage repair (DDR) mutations are known to predict response to PC in solid tumors. However, the predictive value of DDR in PC and IPC of NSCLC remains unclear. Patients diagnosed with advanced or metastatic NSCLC were retrospectively included if they underwent next generation sequencing prior to starting treatment. Primary endpoints were to explore whether DDR mutations (DDRmut) are associated with clinical outcomes of PC and IPC. Secondary end point were to explore the association between DDRmut and the choice to add immunotherapy to chemotherapy, and the impact of different DDR pathways on efficacy in PC and IPC. DDRmut showed a strong association with tumor mutation burden-high (TMB-H) versus DDR wild-type (DDRwt) and higher rates of PD-L1 TPS ≥50% positivity. In 63 patients treated with PC, ORRs were 15.38% and 2.86% for DDRmut and DDRwt subgroup (P=0.1536), and DCRs were 88.46% and 45.72% (P=0.00097) at 6 months after PC. The DDRmut patients had significantly improved median PFS (mPFS) and median overall survival (mOS) than DDRwt group (mPFS: 7.6 vs. 3.9 months, HR =1.93, 95% CI: 1.09 to 3.14, P=0.0220. mOS: 29.9 vs. 20.7 months, HR =2.31, 95% CI: 1.09 to 4.9, P=0.0250). Moreover, among 37 patients treated with IPC, ORRs were 45% and 11.76% for DDRmut and DDRwt patients (P=0.0365), and the DCRs were 95% and 70.58% (P=0.0752), respectively at 6 months after IPC. The DDRmut patients had significantly improved mPFS compared to the DDRwt group (19.5 vs. 4.5 months, HR =3.28, 95% CI: 1.53 to 9.56, P=0.0022). In DDRmut group, mPFS of IPC recipients was significantly better than that of PC recipients (19.5 vs. 7.6 months, HR =2.09, 95% CI: 0.98 to 4.42, P=0.050). There is potential for DDR to serve as a positive predictor of PC and IPC in advanced NSCLC patients.

NCALD as a potential predictive biomarker for the efficacy of platinum-based chemotherapy in ovarian cancer.

Aim: Since reliable response predictors to platinum-based chemotherapy in ovarian cancer (OC) are scarce, we characterize NCALD as apredictive biomarker. Materials & methods: NCALD mRNA (n=100) and protein (n=102) expression was analyzed in OC samples and associated with patient outcome. A stable OC cell line knockdown was generated and cellular response to platinum was explored. Results: High NCALD mRNA and protein expression was significantly associated with longer overall patient survival (p=0.037/0.002). Knockdown experiments revealed a significant association between cisplatin sensitivity and NCALD expression. Conclusion: Low NCALD expression was associated with reduced sensitivity to platinum-based chemotherapy. NCALD may be a new biomarker candidate to identify patients who might benefit from platinum-based chemotherapy.

EP02.01-005 The Efficacy of Platinum-Based Chemotherapy as Adjuvant Therapy in EGFR Mutant Lung Adenocarcinoma

The ADAURA trial reported that osimertinib improved disease-free survival (DFS) compared with placebo as an adjuvant chemotherapy for stage II-IIIA EGFR mutant lung cancer. Currently, platinum-based adjuvant chemotherapy is the standard adjuvant therapy for patients with and without EGFR mutations. This study aimed to evaluate the efficacy of platinum-based adjuvant chemotherapy in stage II-IIIA EGFR mutant lung adenocarcinoma.

Homologous recombination repair gene mutations as a predictive biomarker for immunotherapy in patients with advanced melanoma.

BackgroundNowadays, immunotherapy targeting immune checkpoint receptors is one of the cornerstones of systemic treatment in melanoma. Homologous recombination repair (HRR) is one of the DNA damage response (DDR) pathways, which has been proved to correlate with the efficacy of platinum-based chemotherapy, PARP inhibitor therapy, and immunotherapy in a variety of cancers. However, their predictive value of HRR remained unknown in patients with advanced melanoma.MethodsData of advanced melanoma patients from an independent cohort (Samstein2018) were used to analyze the correlation with immunogenic markers and the prognostic effect of HRR on immunotherapy, and another four cohorts (pooled cohort: Miao2018, Allen 2015, Hugo2016, and Synder2014) were used for validation. Immune infiltration cell scores analyzed by TCGA-SKCM cohort were used to explore potential mechanisms related to the immune microenvironment.ResultsCompared to patients with an HRR wild type (HRRwt), those with HRR mutations (HRRmut) in anti-CTLA-4-treated patients of the Samstein2018 cohort had higher tumor mutation burden (TMB; P = 0.0041) and longer median overall survival (mOS; P = 0.0094). In terms of results validation, it was also confirmed that the mOS (P = 0.0014) of HRRmut patients receiving anti-CTLA-4 therapy was significantly better than that of HRRwt patients in the pooled cohort, and objective response rates (ORR; P = 0.0053) were also found to be significant. However, there was no significant difference in mOS between HRRmut patients who received anti-PD-1/L1 therapy and HRRwt patients in either the discovery (Samstein2018 cohort, P = 0.94) or validation (pooled cohort, P = 0.96) set. Exploratory analysis found that although HRRmut patients showed no significant difference in mOS between anti-CTLA-4 and anti-PD-1/L1 therapy (P = 0.79), the mOS value of the anti-CTLA-4 therapy group (31.7 months) in HRRmut patients was numerically superior to the anti-PD-1/L1 therapy group (27.5 months). In contrast, the mOS of the anti-CTLA-4 therapy group was significantly lower than that of the anti-PD-1/L1 therapy group (12.4 vs. 32.0 months) in HRRwt patients. In addition, transcriptome profiling analysis revealed that the 29 (65.9%)-gene mutation of the HRR pathway associated with reshaping of the immunological microenvironment in melanoma.ConclusionsHRR mutations were associated with a higher TMB level, and better anti-CTLA-4 therapy outcomes. HRR may serve as an independent predictor of anti-CTLA-4 therapy efficacy in patients with advanced melanoma and their clinical value warrants further investigation.