Identification of non-adherence to adjuvant letrozole using a population pharmacokinetics approach in hormone receptor-positive breast cancer patients.

BACKGROUND: Letrozole, an aromatase inhibitor metabolised via CYP2A6 and CYP3A4/5 enzymes, is used as adjuvant therapy for women with hormone receptor (HR)-positive early breast cancer. The objective of this study was to quantify the impact of CYP2A6 genotype on letrozole pharmacokinetics (PK), to identify non-adherent patients using a population approach and explore the possibility of a relationship between non-adherence and early relapse. METHODS: Breast cancer patients enrolled in the prospective PHACS study (ClinicalTrials.gov NCT01127295) and treated with adjuvant letrozole 2.5 mg/day were included. Trough letrozole concentrations (Css,trough) were measured every 6 months for 3 years by a validated LC-MS/MS method. Concentration-time data were analysed using non-linear mixed effects modelling. Three methods were evaluated for identification of non-adherent subjects using the base PK model. RESULTS: 617 patients contributing 2534 plasma concentrations were included and led to a one-compartment PK model with linear absorption and elimination. Model-based methods identified 28% of patients as non-adherent based on high fluctuations of their Css,trough compared to 3% based on patient declarations. The covariate analysis performed in adherent subjects revealed that CYP2A6 intermediate (IM) and slow metabolisers (SM) had 21% (CI95%=12 - 30%) and 46% (CI95%=41 - 51%) lower apparent clearance, respectively, compared to normal and ultrarapid metabolisers (NM+UM). Early relapse (19 patients) was not associated with model-estimated, concentration-based or declared adherence in the total population (p=0.41, p=0.37 and p=0.45, respectively). CONCLUSIONS: These findings will help future investigations focusing on the exposure-efficacy relationship for letrozole in adjuvant setting.

CDK inhibition results in pharmacologic BRCAness increasing sensitivity to olaparib in BRCA1-WT and olaparib resistant in Triple Negative Breast Cancer.

One in three Triple Negative Breast Cancer (TNBC) is Homologous Recombination Deficient (HRD) and susceptible to respond to PARP inhibitor (PARPi), however, resistance resulting from functional HR restoration is frequent. Thus, pharmacologic approaches that induce HRD are of interest. We investigated the effectiveness of CDK-inhibition to induce HRD and increase PARPi sensitivity of TNBC cell lines and PDX models. Two CDK-inhibitors (CDKi), the broad range dinaciclib and the CDK12-specific SR-4835, strongly reduced the expression of key HR genes and impaired HR functionality, as illustrated by BRCA1 and RAD51 nuclear foci obliteration. Consequently, both CDKis showed synergism with olaparib, as well as with cisplatin and gemcitabine, in a range of TNBC cell lines and particularly in olaparib-resistant models. In vivo assays on PDX validated the efficacy of dinaciclib which increased the sensitivity to olaparib of 5/6 models, including two olaparib-resistant and one BRCA1-WT model. However, no olaparib response improvement was observed in vivo with SR-4835. These data support that the implementation of CDK-inhibitors could be effective to sensitize TNBC to olaparib as well as possibly to cisplatin or gemcitabine.

Efficacy of a physiotherapy, yoga and patient education programme for patients with breast cancer and hormone therapy-induced pain: a multicentre randomised study protocol (SKYPE 2).

INTRODUCTION: Osteoarticular pain is experienced by approximately 50% of patients with breast cancer under hormone therapy and can increase the risk of therapy discontinuation. Among complementary therapies, yoga has shown efficacy regarding reduction of fatigue, anxiety, pain due to hormone therapy and inflammation. Personalised patient education programmes increase engagement and motivation, and induce effective behavioural changes. The SKYPE programme, an integrated intervention combining physiotherapy, yoga and patient education, showed promising efficacy on hormone therapy-induced pain in a previous pilot study. In this study, we hypothesised that using theory-based patient education favour learning and practising 15 min of at-home yoga every day to decrease hormone therapy-induced pain. METHODS AND ANALYSIS: This multicentre randomised study will assess the efficacy of the SKYPE programme on pain reduction compared with standard care in patients with breast cancer reporting osteoarticular pain due to hormone therapy. Main secondary objectives will describe pain evolution and characteristics, patient adhesion to yoga sessions and home practice, forward flexibility, quality of life, fatigue, anxiety and compliance to hormone therapy. Patients in the intervention group will participate in 1 weekly educational yoga session of 90 min for 6 weeks, supervised by physiotherapists (period 1). They will also perform daily at-home 15 min yoga sessions for 12 weeks, the total duration of the intervention (periods 1 and 2). Pain will be evaluated during physiotherapy check-ups at baseline (T0), at 6 weeks (T1) and at 12 weeks (T2). ETHICS AND DISSEMINATION: This study was approved by the ethics committee (CPP Ile de France 8 on 22 June 2020). The results will be disseminated to patients and healthcare professionals, and published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04457895.

First-line real-world treatment patterns and survival outcomes in women younger or older than 40 years with metastatic breast cancer in the real-life multicenter French ESME cohort.

AIM: To describe first-line treatment patterns, overall survival (OS) and real-world progression-free survival (rwPFS) in young women (<40) with metastatic breast cancer (mBC), as compared to women aged 40-69. MATERIALS AND METHODS: Data on adult women diagnosed with mBC (2008-2017) were extracted from the ESME mBC database (NCT03275311) which includes consecutive patients starting first-line metastatic treatment in one of the 18 French Comprehensive cancer centers. We reported first-line therapeutic strategy and prognostic factors of OS and rwPFS for women aged < 40 and 40-69. RESULTS: In total, 14,897 mBC women were included (1512 aged <40). HR+ /HER2- mBC was the most frequent subtype. First-line treatment differed between young patients and older ones for HR+ /HER2- and Triple Negative (TN) mBC. Median OS for women aged < 40 and 40-69, respectively, was 46.9 and 46.2 months for HR+ /HER2- mBC; 13.5 and 15.2 for TN mBC; and, 60.7 and 55.1 for HER2 + mBC. Median rwPFS under first line treatment was 11.6 and 11.9 months for HR+ /HER2- in women aged < 40 and 40-69, respectively; 5.5 and 5.9 for TN, and, 13.3 and 12.9 for HER2 + . Factors associated with shorter OS and rwPFS were similar for both women aged < 40 and 40-69 and included ≥ 3 metastatic sites, visceral metastases, and longer MFI, with time-varying effects observed for several prognostic factors. CONCLUSION: Young women presented more frequently with TN and HER2 + subtypes and aggressive mBC than women aged 40-69 did. Prognostic factors of OS and rwPFS were quite similar between age groups and mBC subtypes.

Circulating tumour cells and PD-L1-positive small extracellular vesicles: the liquid biopsy combination for prognostic information in patients with metastatic non-small cell lung cancer.

BACKGROUND: Circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), and extracellular vesicles (EVs) are minimally invasive liquid biopsy biomarkers. This study investigated whether they predict prognosis, alone or in combination, in heterogenous unbiased non-small cell lung cancer (NSCLC) patients. METHODS: Plasma samples of 54 advanced NSCLC patients from a prospective clinical trial. CtDNA mutations were identified using the UltraSEEK™ Lung Panel (MassARRAY® technology). PD-L1 expression was assessed in small EVs (sEVs) using an enzyme-linked immunosorbent assay. RESULTS: At least one ctDNA mutation was detected in 37% of patients. Mutations were not correlated with overall survival (OS) (HR = 1.1, 95% CI = 0.55; 1.83, P = 0.980) and progression-free survival (PFS) (HR = 1.00, 95% CI = 0.57-1.76, P = 0.991). High PD-L1+ sEV concentration was correlated with OS (HR = 1.14, 95% CI = 1.03-1.26, P = 0.016), but not with PFS (HR = 1.08, 95% CI = 0.99-1.18, P = 0.095). The interaction analysis suggested that PD-L1+ sEV correlation with PFS changed in function of CTC presence/absence (P interaction = 0.036). The combination analysis highlighted worse prognosis for patients with CTCs and high PD-L1+ sEV concentration (HR = 7.65, 95% CI = 3.11-18.83, P < 0.001). The mutational statuses of ctDNA and tumour tissue were significantly correlated (P = 0.0001). CONCLUSION: CTCs and high PD-L1+ sEV concentration correlated with PFS and OS, but not ctDNA mutations. Their combined analysis may help to identify patients with worse OS. TRIAL REGISTRATION: NCT02866149, Registered 01 June 2015, https://clinicaltrials.gov/ct2/show/study/NCT02866149 .

Overall Survival With Circulating Tumor Cell Count-Driven Choice of Therapy in Advanced Breast Cancer: A Randomized Trial.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer, the STIC CTC trial established that, for choosing between endocrine therapy (ET) or chemotherapy, the use of circulating tumor cell (CTC) count is noninferior to the investigator's choice in terms of progression-free survival. Here, we report overall survival (OS) results, a secondary end point. Patients were randomly assigned in a 1:1 ratio to have their first-line treatment (ET or chemotherapy) determined by investigators or CTC count (chemotherapy if ≥ 5 CTCs/7.5 mL; ET if low CTC count; CellSearch). OS was assessed at the discontinuation of follow-up. After a median follow-up of 4.7 years, 382 deaths (50.6%) had occurred among 755 patients. Median OS was 51.3 months (95% CI, 46.8 to 55.1) in the CTC arm and 45.5 months (95% CI, 40.9 to 51.1) in the standard arm (hazard ratio [HR] for death, 0.85; 95% CI, 0.69 to 1.03; P = .11). Among 189 patients (25.0%) with ET recommended by clinicians and high CTC count, chemotherapy was superior to ET (HR for death, 0.53; 95% CI, 0.36 to 0.78; P = .001). In case of a discordant estimate, OS data demonstrate the clinical utility of CTC count.

First evidence of AXL expression on circulating tumor cells in metastatic breast cancer patients: A proof-of-concept study.

BACKGROUND: For several years, the AXL tyrosine kinase receptor, a member of the Tyro3-Axl-Mer (TAM) family, has been considered a new strategic target in oncology. AXL overexpression is common in solid tumors and is associated with poor prognosis. In this context, the detection of a subset of circulating tumor cells (CTCs) that express AXL (AXL+ CTCs) could be clinically relevant. METHODS: Immunostaining was performed to assess AXL expression in human breast cancer cell lines. The optimal conditions were established using flow cytometry. Spiking experiments were carried out to optimize the parameters of the CellSearch® system detection test. CTC enumeration and AXL expression were evaluated in patients with metastatic breast cancer (mBC) before treatment initiation. RESULTS: An innovative AXL+ CTC detection assay to be used with the CellSearch® system was developed. In a prospective longitudinal clinical trial, blood samples from 60 patients with untreated mBC were analyzed to detect AXL+ CTCs with this new assay. CTCs were detected in 35/60 patients (58.3%) and AXL+ CTCs were identified in 7 of these 35 patients (11.7% of all patients). CONCLUSION: This newly established AXL+ CTC assay is a promising tool that can be used for liquid biopsy in future clinical trials to stratify and monitor patients with cancer receiving anti-AXL therapies.

Chronological interplay, clinical features, and treatments among patients with cancer and primary Sjögren's syndrome.

OBJECTIVE: While the incidence and type of blood malignancies are well documented amid primary Sjögren's syndrome patients (pSS), data focusing on solid neoplasms are more conflicting. We aimed to describe clinical, pathological, and immunological characteristics of pSS patients with cancers, along with the chronological interplay between the two conditions. METHODS: Outcomes concerning both pSS and cancer were retrospectively collected from Montpellier University Hospital (tertiary center) between 2019 and 2020. pSS characteristics were compared to a control group of pSS patients without cancer. RESULTS: A total of 165 patients with pSS were included: 55 patients with cancer (52 female, mean age 58.4 ± 10.4 years at pSS diagnosis; mean follow-up 10.5 ± 10.1 years, 12 patients had multiple cancers) and 110 controls without cancer. Characteristics of pSS patients with cancers were different from controls mostly for lymphoma prognosis factors. Among the 70 cancers, we recorded 55 solid neoplasms (whom 27 breast cancers and 8 lung cancers, and 82% of adenocarcinomas), with no evidence of disease at the end of follow-up in 85% of them. Among the 15 recorded blood malignancies, ten were lymphomas with an excellent prognosis. Regarding chronological interplay between cancer and pSS, most cancers (43%) were diagnosed close (± 5 years) to pSS diagnosis. Breast cancers were diagnosed before or close to pSS diagnosis (mean delay - 1.8 ± 13.0 years), at an early stage, with only two relapses (no cancer-related death), while lung cancers were diagnosed late after. CONCLUSIONS: The tight chronological interplay between breast cancer and pSS and the intriguing pathological and immunological pattern of pSS in these patients suggest a hypothesis of immune control of cancer.

NK cells in peripheral blood carry trogocytosed tumor antigens from solid cancer cells.

The innate immune lymphocyte lineage natural killer (NK) cell infiltrates tumor environment where it can recognize and eliminate tumor cells. NK cell tumor infiltration is linked to patient prognosis. However, it is unknown if some of these antitumor NK cells leave the tumor environment. In blood-borne cancers, NK cells that have interacted with leukemic cells are recognized by the co-expression of two CD45 isoforms (CD45RARO cells) and/or the plasma membrane presence of tumor antigens (Ag), which NK cells acquire by trogocytosis. We evaluated solid tumor Ag uptake by trogocytosis on NK cells by performing co-cultures in vitro. We analyzed NK population subsets by unsupervised dimensional reduction techniques in blood samples from breast tumor (BC) patients and healthy donors (HD). We confirmed that NK cells perform trogocytosis from solid cancer cells in vitro. The extent of trogocytosis depends on the target cell and the antigen, but not on the amount of Ag expressed by the target cell or the sensitivity to NK cell killing. We identified by FlowSOM (Self-Organizing Maps) several NK cell clusters differentially abundant between BC patients and HD, including anti-tumor NK subsets with phenotype CD45RARO+CD107a+. These analyses showed that bona-fide NK cells that have degranulated were increased in patients and, additionally, these NK cells exhibit trogocytosis of solid tumor Ag on their surface. However, the frequency of NK cells that have trogocytosed is very low and much lower than that found in hematological cancer patients, suggesting that the number of NK cells that exit the tumor environment is scarce. To our knowledge, this is the first report describing the presence of solid tumor markers on circulating NK subsets from breast tumor patients. This NK cell immune profiling could lead to generate novel strategies to complement established therapies for BC patients or to the use of peripheral blood NK cells in the theranostic of solid cancer patients after treatment.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer.

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Real-World Impact of Adjuvant Anti-HER2 Treatment on Characteristics and Outcomes of Women With HER2-Positive Metastatic Breast Cancer in the ESME Program.

BACKGROUND: Although adjuvant cancer treatments increase cure rates, they may induce clonal selection and tumor resistance. Information still lacks as whether (neo)adjuvant anti-HER2 treatments impact the patterns of recurrence and outcomes of HER2-positive (HER2+) metastatic breast cancer (MBC). We aimed to assess this in the large multicenter ESME real-world database. PATIENTS AND METHODS: We examined the characteristics and outcomes (overall survival (OS) and progression-free survival under first-line treatment (PFS1)) of HER2+ patients with MBC from the French ESME program with recurrent disease, as a function of the previous receipt of adjuvant trastuzumab. Multivariable analyses used Cox models adjusted for baseline demographic, prognostic factors, adjuvant treatment received, and disease-free interval. RESULTS: Two thousand one hundred and forty-three patients who entered the ESME cohort between 2008 and 2017 had a recurrent HER2+ MBC. Among them, 56% had received (neo)adjuvant trastuzumab and 2.5% another anti-HER2 in this setting. Patients pre-exposed to trastuzumab were younger, had a lower disease-free interval, more HR-negative disease and more metastatic sites. While the crude median OS appeared inferior in patients exposed to adjuvant trastuzumab, as compared to those who did not (37.2 (95%CI 34.4-40.3) versus 53.5 months (95% CI: 47.6-60.1)), this difference disappeared in the multivariable model (HR = 1.05, 95%CI 0.91-1.22). The same figures were observed for PFS1. CONCLUSIONS: Among patients with relapsed HER2+ MBC, the receipt of adjuvant trastuzumab did not independently predict for worse outcomes when adjusted to other prognostic factors.

[Therapeutic advances in HER2+ breast cancer]. / Avancées thérapeutiques dans le cancer du sein HER2.

THERAPEUTIC ADVANCES IN HER2+ BREAST CANCER. 58,000 new cases of breast cancer occured in France in 2018, of which 15-20% are HER2-positive. HER2-targeted therapies deeply modified the management of these tumors, first by the introduction of monoclonal antibodies such as trastuzumab and pertuzumab and tyrosine kinase inhibitors such as tucatinib, and more recently by antibody drug conjugates (ADC), with trastuzumab-deruxtecan in the forefront. In the localized stage, neoadjuvant chemotherapy associated with trastuzumab is now the standard strategy, allowing the adjuvant strategy to be adapted to the therapeutic response, with the use of another ADC, T-DM1, in the absence of pathological complete response. These various therapeutic advances have led to a significant improvement in the prognosis of HER2-positive breast cancer, whether at the metastatic or localized stage.

AVANCÉES THÉRAPEUTIQUES DANS LE CANCER DU SEIN HER2+. Le cancer du sein représente 58 000 nouveaux cas en France en 2018, dont 15 à 20 % présentent une surexpression de HER2. Les traitements ciblant HER2 ont modifié la prise en charge des patientes : tout d'abord grâce aux anticorps tels le trastuzumab et le pertuzumab ainsi qu'aux inhibiteurs de tyrosine kinase comme le tucatinib, puis plus récemment aux anticorps conjugués, avec au premier plan le trastuzumab déruxtécan. Au stade localisé, la stratégie de chimiothérapie néoadjuvante associée au trastuzumab devient la règle, permettant d'adapter la stratégie adjuvante à la réponse au traitement, avec utilisation d'un autre anticorps conjugué, le T-DM1, en l'absence de réponse complète histologique. Ces différentes avancées ont permis une nette amélioration du pronostic du cancer du sein HER2 surexprimé, que ce soit au stade métastatique ou localisé.

Real-world clinical and survival outcomes of patients with early relapsed triple-negative breast cancer from the ESME national cohort.

BACKGROUND: Early metastatic relapse of triple-negative breast cancer (mTNBC) after anthracyclins and/or taxanes based (A/T) primary treatment represents a highly aggressive cancer situation requiring urgent characterisation and handling. Epidemio-Strategy-Medico-Economical-Metastatic Breast Cancer (ESME-MBC) database, a multicenter, national, observational cohort (NCT03275311) provides recent data on this entity. METHODS: All ESME patients diagnosed between 2008 and 2020 with mTNBC occurring as a relapse after a systemic neoadjuvant/adjuvant taxane and/or anthracycline-based chemotherapy were included. Early relapses were defined by a metastatic diagnosis up to 12 months of the end of neo/adjuvant A/T chemotherapy. We assessed overall survival (OS) and progression-free-survival under first-line treatment (PFS1) by early versus late relapse (≥12 months). RESULTS: Patients with early relapse (N = 881, 46%) were younger and had a larger tumour burden at primary diagnosis than those with late relapses (N = 1045). Early relapse rates appeared stable over time. Median OS was 10.1 months (95% CI 9.3-10.9) in patients with early relapse versus 17.1 months (95% CI 15.7-18.2) in those with late relapse (adjusted hazard-ratio (aHR): 1.92 (95% CI 1.73-2.13); p < 0.001). The median PFS1 was respectively 3.1 months (95% CI 2.9-3.4) and 5.3 months (95% CI 5.1-5.8); (aHR: 1.66; [95% CI 1.50-1.83]; p < 0.001). Among early relapsed patients, a higher number of metastatic sites, visceral disease but not treatment types, were independently associated with a poorer OS. CONCLUSION: These real-world data provide strong evidence on the dismal prognosis, higher treatment resistance and major unmet medical need associated with early relapsed mTNBC. Database registration: clinicaltrials.gov Identifier NCT032753.

Intrathecal trastuzumab versus alternate routes of delivery for HER2-targeted therapies in patients with HER2+ breast cancer leptomeningeal metastases.

BACKGROUND: Patients with HER2+ breast cancer (BC) frequently develop leptomeningeal metastases (LM). While HER2-targeted therapies have demonstrated efficacy in the neoadjuvant, adjuvant, and metastatic settings, including for parenchymal brain metastases, their efficacy for patients with LM has not been studied in a randomized controlled trial. However, several single-armed prospective studies, case series and case reports have studied oral, intravenous, or intrathecally administered HER2-targeted therapy regimens for patients with HER2+ BC LM. METHODS: We conducted a systematic review and meta-analysis of individual patient data to evaluate the efficacy of HER2-targeted therapies in HER2+ BC LM in accordance with PRISMA guidelines. Targeted therapies evaluated were trastuzumab (intrathecal or intravenous), pertuzumab, lapatinib, neratinib, tucatinib, trastuzumab-emtansine and trastuzumab-deruxtecan. The primary endpoint was overall survival (OS), with CNS-specific progression-free survival (PFS) as a secondary endpoint. RESULTS: 7780 abstracts were screened, identifying 45 publications with 208 patients, corresponding to 275 lines of HER2-targeted therapy for BC LM which met inclusion criteria. In univariable and multivariable analyses, we observed no significant difference in OS and CNS-specific PFS between intrathecal trastuzumab compared to oral or intravenous administration of HER2-targeted therapy. Anti-HER2 monoclonal antibody-based regimens did not demonstrate superiority over HER2 tyrosine kinase inhibitors. In a cohort of 15 patients, treatment with trastuzumab-deruxtecan was associated with prolonged OS compared to other HER2-targeted therapies and compared to trastuzumab-emtansine. CONCLUSIONS: The results of this meta-analysis, comprising the limited data available, suggest that intrathecal administration of HER2-targeted therapy for patients with HER2+ BC LM confers no additional benefit over oral and/or IV treatment regimens. Although the number of patients receiving trastuzumab deruxtecan in this cohort is small, this novel agent offers promise for this patient population and requires further investigation in prospective studies.

Radiological response of leptomeningeal metastases according to revised RANO criteria is associated with overall survival in breast cancer patients.

Assessment of treatment response in patients (pts) with leptomeningeal metastases (LM) represents a significant challenge and standardized criteria are needed. In 2017, the RANO LM Working Group proposed a standardized scorecard to evaluate MRI findings (further simplified in 2019). Here, we aim to validate the prognostic impact of response to treatment assessed using this tool in a multicentric cohort of breast cancer (BC) pts. Pts with BC-related LM diagnosed at two institutions between 2005 and 2018 were identified. Baseline and follow-up MRI scans were centrally reviewed and response assessment was evaluated using 2019 revised RANO LM criteria. A total of 142 pts with BC-related LM and available baseline brain MRI imaging were identified; 60 of them had at least one follow-up MRI. In this subgroup, median overall survival (OS) was 15.2 months (95%CI 9.5-21.0). At first re-evaluation, radiological response by RANO criteria was: complete response (CR) in 2 pts (3%), partial response (PR) in 12 (20%), stable disease (SD) in 33 (55%) and progression of disease (PD) in 13 (22%). Median OS was 31.1 months (HR 0.10, 95%CI 0.01-0.78) in pts with CR, 16.1 months (HR 0.41, 95%CI 0.17-0.97) in pts with PR, 17.9 months (HR 0.45, 95%CI 0.22-0.91) in pts with SD and 9.5 months in pts with PD (P = .029). A second blinded evaluation showed a moderate interobserver agreement (K = 0.562). Radiological response according to 2019 RANO criteria is significantly associated with OS in pts with BC-related LM, thus supporting the use of this evaluation tool both in trials and clinical practice.

BRCA1-methylated triple negative breast cancers previously exposed to neoadjuvant chemotherapy form RAD51 foci and respond poorly to olaparib.

Background: About 15% of Triple-Negative-Breast-Cancer (TNBC) present silencing of the BRCA1 promoter methylation and are assumed to be Homologous Recombination Deficient (HRD). BRCA1-methylated (BRCA1-Me) TNBC could, thus, be eligible to treatment based on PARP-inhibitors or Platinum salts. However, their actual HRD status is discussed, as these tumors are suspected to develop resistance after chemotherapy exposure. Methods: We interrogated the sensitivity to olaparib vs. carboplatin of 8 TNBC Patient-Derived Xenografts (PDX) models. Four PDX corresponded to BRCA1-Me, of which 3 were previously exposed to NeoAdjuvant-Chemotherapy (NACT). The remaining PDX models corresponded to two BRCA1-mutated (BRCA1-Mut) and two BRCA1-wild type PDX that were respectively included as positive and negative controls. The HRD status of our PDX models was assessed using both genomic signatures and the functional BRCA1 and RAD51 nuclear foci formation assay. To assess HR restoration associated with olaparib resistance, we studied pairs of BRCA1 deficient cell lines and their resistant subclones. Results: The 3 BRCA1-Me PDX that had been exposed to NACT responded poorly to olaparib, likewise BRCA1-WT PDX. Contrastingly, 3 treatment-naïve BRCA1-deficient PDX (1 BRCA1-Me and 2 BRCA1-mutated) responded to olaparib. Noticeably, the three olaparib-responsive PDX scored negative for BRCA1- and RAD51-foci, whereas all non-responsive PDX models, including the 3 NACT-exposed BRCA1-Me PDX, scored positive for RAD51-foci. This suggested HRD in olaparib responsive PDX, while non-responsive models were HR proficient. These results were consistent with observations in cell lines showing a significant increase of RAD51-foci in olaparib-resistant subclones compared with sensitive parental cells, suggesting HR restoration in these models. Conclusion: Our results thus support the notion that the actual HRD status of BRCA1-Me TNBC, especially if previously exposed to chemotherapy, may be questioned and should be verified using the BRCA1- and RAD51-foci assay.

Multiple PIK3CA mutation clonality correlates with outcomes in taselisib + fulvestrant-treated ER+/HER2-, PIK3CA-mutated breast cancers.

BACKGROUND: Mutations in the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), encoded by the PIK3CA gene, cause dysregulation of the PI3K pathway in 35-40% of patients with HR+/HER2- breast cancer. Preclinically, cancer cells harboring double or multiple PIK3CA mutations (mut) elicit hyperactivation of the PI3K pathway leading to enhanced sensitivity to p110α inhibitors. METHODS: To understand the role of multiple PIK3CAmut in predicting response to p110α inhibition, we estimated the clonality of multiple PIK3CAmut in circulating tumor DNA (ctDNA) from patients with HR+/HER2- metastatic breast cancer enrolled to a prospectively registered clinical trial of fulvestrant ± taselisib, and analyzed the subgroups against co-altered genes, pathways, and outcomes. RESULTS: ctDNA samples with clonal multiple PIK3CAmut had fewer co-alterations in receptor tyrosine kinase (RTK) or non-PIK3CA PI3K pathway genes compared to samples with subclonal multiple PIK3CAmut indicating a strong reliance on the PI3K pathway. This was validated in an independent cohort of breast cancer tumor specimens that underwent comprehensive genomic profiling. Furthermore, patients whose ctDNA harbored clonal multiple PIK3CAmut exhibited a significantly higher response rate and longer progression-free survival vs subclonal multiple PIK3CAmut. CONCLUSIONS: Our study establishes clonal multiple PIK3CAmut as an important molecular determinant of response to p110α inhibition and provides rationale for further clinical investigation of p110α inhibitors alone or with rationally-selected therapies in breast cancer and potentially other solid tumor types.

Association between progression-free survival and overall survival in women receiving first-line treatment for metastatic breast cancer: evidence from the ESME real-world database.

BACKGROUND: Overall survival (OS) is the gold standard endpoint to assess treatment efficacy in cancer clinical trials. In metastatic breast cancer (mBC), progression-free survival (PFS) is commonly used as an intermediate endpoint. Evidence remains scarce regarding the degree of association between PFS and OS. Our study aimed to describe the individual-level association between real-world PFS (rwPFS) and OS according to first-line treatment in female patients with mBC managed in real-world setting for each BC subtype (defined by status for both hormone-receptor [HR] expression and HER2 protein expression/gene amplification). METHODS: We extracted data from the ESME mBC database (NCT03275311) which gathers deidentified data from consecutive patients managed in 18 French Comprehensive Cancer Centers. Adult women diagnosed with mBC between 2008 and 2017 were included. Endpoints (PFS, OS) were described using the Kaplan-Meier method. Individual-level associations between rwPFS and OS were estimated using the Spearman's correlation coefficient. Analyses were conducted by tumor subtype. RESULTS: 20,033 women were eligible. Median age was 60.0 years. Median follow-up duration was 62.3 months. Median rwPFS ranged from 6.0 months (95% CI 5.8-6.2) for HR-/HER2 - subtype to 13.3 months (36% CI 12.7-14.3) for HR + /HER2 + subtype. Correlation coefficients were highly variable across subtypes and first-line (L1) treatments. Among patients with HR - /HER2 - mBC, correlation coefficients ranged from 0.73 to 0.81, suggesting a strong rwPFS/OS association. For HR + /HER2 + mBC patients, the individual-level associations were weak to strong with coefficients ranging from 0.33 to 0.43 for monotherapy and from 0.67 to 0.78 for combined therapies. CONCLUSIONS: Our study provides comprehensive information on individual-level association between rwPFS and OS for L1 treatments in mBC women managed in real-life practice. Our results could be used as a basis for future research dedicated to surrogate endpoint candidates.

ER+, HER2- advanced breast cancer treated with taselisib and fulvestrant: genomic landscape and associated clinical outcomes.

Taselisib is a potent ß-sparing phosphatidylinositol 3-kinase (PI3K) inhibitor that, with endocrine therapy, improves outcomes in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA)-mutated (PIK3CAmut) advanced breast cancer. To understand alterations associated with response to PI3K inhibition, we analysed circulating tumour DNA (ctDNA) from participants enrolled in the SANDPIPER trial. Participants were designated as either PIK3CAmut or PIK3CA no mutation was detected (NMD) per baseline ctDNA. The top mutated genes and tumour fraction estimates identified were analysed for their association with outcomes. In participants with PIK3CAmut ctDNA treated with taselisib + fulvestrant, tumour protein p53 (TP53; encoding p53) and fibroblast growth factor receptor 1 (FGFR1) alterations were associated with shorter progression-free survival (PFS) compared to participants with NMD in these genes. Conversely, participants with PIK3CAmut ctDNA harbouring a neurofibromin 1 (NF1) alteration or high baseline tumour fraction estimate experienced improved PFS upon treatment with taselisib + fulvestrant compared to placebo + fulvestrant. Broadly, alterations in oestrogen receptor (ER), PI3K and p53 pathway genes were associated with resistance to taselisib + fulvestrant in participants with PIK3CAmut ctDNA. Altogether, we demonstrated the impact of genomic (co-)alterations on outcomes with one of the largest clinico-genomic datasets of ER+, HER2-, PIK3CAmut breast cancer patients treated with a PI3K inhibitor.