Real-world study: Impact of multidisciplinary management of apalutamide-associated adverse events in prostate cancer.

OBJECTIVE: To analyse the adverse events (AEs) associated with apalutamide and the impact of a multidisciplinary team (MDT) protocol on its management at a tertiary care hospital in a real-world setting. METHODS: This was an observational, prospective, cohort study based on real-world evidence at the Hospital Clínic de Barcelona. Includes patients diagnosed with metastatic hormone-sensitive prostate cancer (mHSPC) or high-risk nonmetastatic castration-resistant prostate cancer (nmCRPC) and who started treatment with apalutamide between May 2019 and March 2023 in a real-world clinical setting. RESULTS: Of the 121 patients treated with apalutamide, 52.1% experienced an AE, 19.8% experienced temporarily interruption or a reduction in the dose of apalutamide, and 13.2% discontinued treatment due to AEs. Without MDT protocol (49 patients), 24.5% of patients had to temporarily interrupt or reduce the dose of apalutamide due to AEs, with a median time from the start of treatment of 10.1 months, and 24.5% discontinued apalutamide due to AEs, with a median time from the start of treatment of 3.1 months. Meanwhile, whit MDT protocol (72 patients), 16.7% of patients had to temporarily interrupt or reduce the dose of apalutamide due to AEs, with a median time from the start of treatment of 1.6 months, and 5.6% discontinued apalutamide due to AEs, with a median time from the start of treatment of 4 months. The risk reduction associated with treatment discontinuation was statistically significant (p-value = 0.003). CONCLUSIONS: This study highlights the importance of MDT management of AEs associated with apalutamide to reduce treatment discontinuation.

Development and Independent Validation of a Prognostic Gene Expression Signature Based on RB1, PTEN, and TP53 in Metastatic Hormone-sensitive Prostate Cancer Patients.

BACKGROUND: Androgen deprivation therapy (ADT) with docetaxel (D) and/or antiandrogen receptor therapies (ARTs) are the standard therapies in metastatic hormone-sensitive prostate cancer (mHSPC). Alterations in the tumor suppressor genes (TSGs) RB1, PTEN, and TP53 are associated with an aggressive evolution and treatment resistance in castration-resistant prostate cancer (CRPC). OBJECTIVE: To study the clinical implications of TSG mRNA expression in mHSPC patients. DESIGN, SETTING, AND PARTICIPANTS: This is a multicenter retrospective biomarker study in mHSPC patients. TSGlow status was defined when two or more out of the three TSGs presented low RNA expression by nCounter in formalin-fixed paraffin-embedded samples and TSGwt for the remaining cases. The microarray data from the CHAARTED trial were analyzed as an independent validation cohort. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Molecular data were correlated with CRPC-free survival (CRPC-FS) and overall survival (OS) by the Kaplan-Meier method and multivariate Cox analysis. RESULTS AND LIMITATIONS: A total of 226 patients were included, of whom 218 were eligible: 93 were treated with ADT and 125 with ADT + D; 75.7% presented de novo stage IV and 67.9% high-volume disease. TSGlow (19.2%) was independently correlated with shorter CRPC-FS (hazard ratio [HR] 1.8, p = 0.002) and OS (HR 2, p = 0.002). In the CHAARTED trial, TSGlow was independently correlated with lower CRPC-FS (HR 2.2, p = 0.02); no differences in clinical outcomes according to treatment were observed in TSGlow patients, while a significant benefit was observed for ADT + D in the TSGwt group for CRPC-FS (HR 0.4, p < 0.001) and OS (HR 0.4, p = 0.001). However, no interaction was observed between TSG signature and treatment in either series. Study limitations are the retrospective design, small sample size, and lack of inclusion of patients treated with ADT + ART. CONCLUSIONS: TSGlow expression correlates with adverse outcomes in patients with mHSPC. The investigation of new therapeutic strategies in these patients is warranted. PATIENT SUMMARY: The low RNA expression of tumor suppressor genes in the tumors is correlated with adverse outcomes in patients with metastatic hormone-sensitive prostate cancer.

Targeting myeloid chemotaxis to reverse prostate cancer therapy resistance.

Inflammation is a hallmark of cancer1. In patients with cancer, peripheral blood myeloid expansion, indicated by a high neutrophil-to-lymphocyte ratio, associates with shorter survival and treatment resistance across malignancies and therapeutic modalities2-5. Whether myeloid inflammation drives progression of prostate cancer in humans remain unclear. Here we show that inhibition of myeloid chemotaxis can reduce tumour-elicited myeloid inflammation and reverse therapy resistance in a subset of patients with metastatic castration-resistant prostate cancer (CRPC). We show that a higher blood neutrophil-to-lymphocyte ratio reflects tumour myeloid infiltration and tumour expression of senescence-associated mRNA species, including those that encode myeloid-chemoattracting CXCR2 ligands. To determine whether myeloid cells fuel resistance to androgen receptor signalling inhibitors, and whether inhibiting CXCR2 to block myeloid chemotaxis reverses this, we conducted an investigator-initiated, proof-of-concept clinical trial of a CXCR2 inhibitor (AZD5069) plus enzalutamide in patients with metastatic CRPC that is resistant to androgen receptor signalling inhibitors. This combination was well tolerated without dose-limiting toxicity and it decreased circulating neutrophil levels, reduced intratumour CD11b+HLA-DRloCD15+CD14- myeloid cell infiltration and imparted durable clinical benefit with biochemical and radiological responses in a subset of patients with metastatic CRPC. This study provides clinical evidence that senescence-associated myeloid inflammation can fuel metastatic CRPC progression and resistance to androgen receptor blockade. Targeting myeloid chemotaxis merits broader evaluation in other cancers.

Transcriptional Profile Associated with Clinical Outcomes in Metastatic Hormone-Sensitive Prostate Cancer Treated with Androgen Deprivation and Docetaxel.

(1) Background: Androgen deprivation therapy (ADT) and docetaxel (DX) combination is a standard therapy for metastatic hormone-sensitive prostate cancer (mHSPC) patients. (2) Methods: We investigate if tumor transcriptomic analysis predicts mHSPC evolution in a multicenter retrospective biomarker study. A customized panel of 184 genes was tested in mRNA from tumor samples by the nCounter platform in 125 mHSPC patients treated with ADT+DX. Gene expression was correlated with castration-resistant prostate cancer-free survival (CRPC-FS) and overall survival (OS). (3) Results: High expression of androgen receptor (AR) signature was independently associated with longer CRPC-FS (hazard ratio (HR) 0.6, 95% confidence interval (CI) 0.3-0.9; p = 0.015), high expression of estrogen receptor (ESR) signature with longer CRPC-FS (HR 0.6, 95% CI 0.4-0.9; p = 0.019) and OS (HR 0.5, 95% CI 0.2-0.9, p = 0.024), and lower expression of tumor suppressor genes (TSG) (RB1, PTEN and TP53) with shorter OS (HR 2, 95% CI 1-3.8; p = 0.044). ARV7 expression was independently associated with shorter CRPC-FS (HR 1.5, 95% CI 1.1-2.1, p = 0.008) and OS (HR 1.8, 95% CI 1.2-2.6, p = 0.004), high ESR2 was associated with longer OS (HR 0.5, 95% CI 0.2-1, p = 0.048) and low expression of RB1 was independently associated with shorter OS (HR 1.9, 95% CI 1.1-3.2, p = 0.014). (4) Conclusions: AR, ESR, and TSG expression signatures, as well as ARV7, RB1, and ESR2 expression, have a prognostic value in mHSPC patients treated with ADT+DX.

HER3 Is an Actionable Target in Advanced Prostate Cancer.

It has been recognized for decades that ERBB signaling is important in prostate cancer, but targeting ERBB receptors as a therapeutic strategy for prostate cancer has been ineffective clinically. However, we show here that membranous HER3 protein is commonly highly expressed in lethal prostate cancer, associating with reduced time to castration resistance (CR) and survival. Multiplex immunofluorescence indicated that the HER3 ligand NRG1 is detectable primarily in tumor-infiltrating myelomonocytic cells in human prostate cancer; this observation was confirmed using single-cell RNA sequencing of human prostate cancer biopsies and murine transgenic prostate cancer models. In castration-resistant prostate cancer (CRPC) patient-derived xenograft organoids with high HER3 expression as well as mouse prostate cancer organoids, recombinant NRG1 enhanced proliferation and survival. Supernatant from murine bone marrow-derived macrophages and myeloid-derived suppressor cells promoted murine prostate cancer organoid growth in vitro, which could be reversed by a neutralizing anti-NRG1 antibody and ERBB inhibition. Targeting HER3, especially with the HER3-directed antibody-drug conjugate U3-1402, exhibited antitumor activity against HER3-expressing prostate cancer. Overall, these data indicate that HER3 is commonly overexpressed in lethal prostate cancer and can be activated by NRG1 secreted by myelomonocytic cells in the tumor microenvironment, supporting HER3-targeted therapeutic strategies for treating HER3-expressing advanced CRPC. SIGNIFICANCE: HER3 is an actionable target in prostate cancer, especially with anti-HER3 immunoconjugates, and targeting HER3 warrants clinical evaluation in prospective trials.

Glutamine and Cholesterol Plasma Levels and Clinical Outcomes of Patients with Metastatic Castration-Resistant Prostate Cancer Treated with Taxanes.

Altered metabolism is a hallmark of cancer. Malignant cells metabolise glutamine to fulfil their metabolic needs. In prostate cancer, androgen receptor signalling promotes glutamine metabolism, which is also involved in cholesterol homeostasis. We aimed to determine whether the plasma glutamine levels correlate with the blood lipid profile, clinical characteristics and outcomes in patients with metastatic castration resistance prostate cancer (mCRPC) undergoing taxanes. We retrospectively assessed the glutamine and glutamate levels in plasma samples by a bioluminescent assay. Pre-treatment glutamine, glutamate, cholesterol and triglycerides levels were correlated with patients' clinical characteristics, taxanes response and clinical outcomes. Seventy-five patients with mCRPC treated with taxanes were included. The plasma glutamine levels were significantly higher in patients that received abiraterone or enzalutamide prior to taxanes (p = 0.003). Besides, patients with low glutamine levels were more likely to present a PSA response to taxanes (p = 0.048). Higher glutamine levels were significantly correlated with shorter biochemical/clinical progression-free survival (PSA/RX-PFS) (median 2.5 vs. 4.2 months; p = 0.048) and overall survival (OS) (median 12.6 vs. 20.3; p = 0.008). High cholesterol levels independently predicted early PSA/RX-PFS (p = 0.034). High glutamine and cholesterol in the plasma from patients with mCRPC were associated with adverse clinical outcomes, supporting the relevance of further research on metabolism in prostate cancer progression.

Advanced Prostate Cancer with ATM Loss: PARP and ATR Inhibitors.

BACKGROUND: Deleterious ATM alterations are found in metastatic prostate cancer (PC); PARP inhibition has antitumour activity against this subset, but only some ATM loss PCs respond. OBJECTIVE: To characterise ATM-deficient lethal PC and to study synthetic lethal therapeutic strategies for this subset. DESIGN, SETTING, AND PARTICIPANTS: We studied advanced PC biopsies using validated immunohistochemical (IHC) and next-generation sequencing (NGS) assays. In vitro cell line models modified using CRISPR-Cas9 to impair ATM function were generated and used in drug-sensitivity and functional assays, with validation in a patient-derived model. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: ATM expression by IHC was correlated with clinical outcome using Kaplan-Meier curves and log-rank test; sensitivity to different drug combinations was assessed in the preclinical models. RESULTS AND LIMITATIONS: Overall, we detected ATM IHC loss in 68/631 (11%) PC patients in at least one biopsy, with synchronous and metachronous intrapatient heterogeneity; 46/71 (65%) biopsies with ATM loss had ATM mutations or deletions by NGS. ATM IHC loss was not associated with worse outcome from advanced disease, but ATM loss was associated with increased genomic instability (NtAI:number of subchromosomal regions with allelic imbalance extending to the telomere, p = 0.005; large-scale transitions, p = 0.05). In vitro, ATM loss PC models were sensitive to ATR inhibition, but had variable sensitivity to PARP inhibition; superior antitumour activity was seen with combined PARP and ATR inhibition in these models. CONCLUSIONS: ATM loss in PC is not always detected by targeted NGS, associates with genomic instability, and is most sensitive to combined ATR and PARP inhibition. PATIENT SUMMARY: Of aggressive prostate cancers, 10% lose the DNA repair gene ATM; this loss may identify a distinct prostate cancer subtype that is most sensitive to the combination of oral drugs targeting PARP and ATR.

Clinical Utility of Circulating Tumour Cell Androgen Receptor Splice Variant-7 Status in Metastatic Castration-resistant Prostate Cancer.

BACKGROUND: Detection of androgen receptor splice variant-7 (AR-V7) mRNA in circulating tumour cells (CTCs) is associated with worse outcome in metastatic castration-resistant prostate cancer (mCRPC). However, studies rarely report comparisons with CTC counts and biopsy AR-V7 protein expression. OBJECTIVE: To determine the reproducibility of AdnaTest CTC AR-V7 testing, and associations with clinical characteristics, CellSearch CTC counts, tumour biopsy AR-V7 protein expression and overall survival (OS). DESIGN, SETTING, AND PARTICIPANTS: CTC AR-V7 status was determined for 227 peripheral blood samples, from 181 mCRPC patients with CTC counts (202 samples; 136 patients) and matched mCRPC biopsies (65 samples; 58 patients). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: CTC AR-V7 status was associated with clinical characteristics, CTC counts, and tissue biopsy AR-V7 protein expression. The association of CTC AR-V7 status and other baseline variables with OS was determined. RESULTS AND LIMITATIONS: Of the samples, 35% were CTC+/AR-V7+. CTC+/AR-V7+ samples had higher CellSearch CTC counts (median CTC; interquartile range [IQR]: 60, 19-184 vs 9, 2-64; Mann-Whitney test p<0.001) and biopsy AR-V7 protein expression (median H-score, IQR: 100, 63-148 vs 15, 0-113; Mann-Whitney test p=0.004) than CTC+/AR-V7- samples. However, both CTC- (63%) and CTC+/AR-V7- (62%) patients had detectable AR-V7 protein in contemporaneous biopsies. After accounting for baseline characteristics, there was shorter OS in CTC+/AR-V7+ patients than in CTC- patients (hazard ratio [HR] 2.13; 95% confidence interval [CI] 1.23-3.71; p=0.02); surprisingly, there was no evidence that CTC+/AR-V7+ patients had worse OS than CTC+/AR-V7- patients (HR 1.26; 95% CI 0.73-2.17; p=0.4). A limitation of this study was the heterogeneity of treatment received. CONCLUSIONS: Studies reporting the prognostic relevance of CTC AR-V7 status must account for CTC counts. Discordant CTC AR-V7 results and AR-V7 protein expression in matched, same-patient biopsies are reported. PATIENT SUMMARY: Liquid biopsies that determine circulating tumour cell androgen receptor splice variant-7 status have the potential to impact treatment decisions in metastatic castration-resistant prostate cancer patients. Robust clinical qualification of these assays is required before their routine use.

Activation of MAPK Signaling by CXCR7 Leads to Enzalutamide Resistance in Prostate Cancer.

Castration-resistant prostate cancer (CRPC) that has developed resistance to the new-generation androgen receptor (AR) antagonist enzalutamide is a lethal disease. Transcriptome analysis of multiple prostate cancer models identified CXCR7, an atypical chemokine receptor, as one of the most upregulated genes in enzalutamide-resistant cells. AR directly repressed CXCR7 by binding to an enhancer 110 kb downstream of the gene and expression was restored upon androgen deprivation. We demonstrate that CXCR7 is a critical regulator of prostate cancer sensitivity to enzalutamide and is required for CRPC growth in vitro and in vivo. Elevated CXCR7 activated MAPK/ERK signaling through ligand-independent, but ß-arrestin 2-dependent mechanisms. Examination of patient specimens showed that CXCR7 and pERK levels increased significantly from localized prostate cancer to CRPC and further upon enzalutamide resistance. Preclinical studies revealed remarkable efficacies of MAPK/ERK inhibitors in suppressing enzalutamide-resistant prostate cancer. Overall, these results indicate that CXCR7 may serve as a biomarker of resistant disease in patients with prostate cancer and that disruption of CXCR7 signaling may be an effective strategy to overcome resistance. SIGNIFICANCE: These findings identify CXCR7-mediated MAPK activation as a mechanism of resistance to second-generation antiandrogen therapy, highlighting the therapeutic potential of MAPK/ERK inhibitors in CRPC.

Dancing with the DNA damage response: next-generation anti-cancer therapeutic strategies.

Maintenance of genomic stability is a critical determinant of cell survival and relies on the coordinated action of the DNA damage response (DDR), which orchestrates a network of cellular processes, including DNA replication, DNA repair and cell-cycle progression. In cancer, the critical balance between the loss of genomic stability in malignant cells and the DDR provides exciting therapeutic opportunities. Drugs targeting DDR pathways taking advantage of clinical synthetic lethality have already shown therapeutic benefit - for example, the PARP inhibitor olaparib has shown benefit in BRCA-mutant ovarian and breast cancer. Olaparib has also shown benefit in metastatic prostate cancer in DDR-defective patients, expanding the potential biomarker of response beyond BRCA. Other agents and combinations aiming to block the DDR while pushing damaged DNA through the cell cycle, including PARP, ATR, ATM, CHK and DNA-PK inhibitors, are in development. Emerging work is also uncovering how the DDR interacts intimately with the host immune response, including by activating the innate immune response, further suggesting that clinical applications together with immunotherapy may be beneficial. Here, we review recent considerations related to the DDR from a clinical standpoint, providing a framework to address future directions and clinical opportunities.

Cardiovascular safety of abiraterone acetate in metastatic castration-resistant prostate cancer patients: a prospective evaluation.

AIM: The aim of this study is to evaluate cardiotoxicity of abiraterone acetate (AA) in metastatic castration-resistant prostate cancer patients (pts) with cardiovascular comorbidities or coronary artery disease (CAD) risk factors. PATIENTS & METHODS: We prospectively analyzed pts receiving AA in order to evaluate correlations between cardiotoxicity onset and CAD risk factors or cardiovascular comorbidities. RESULTS: Eighty-seven pts were enrolled, with median treatment duration of 9 months (1-44). At baseline, 84 pts (96%) had CAD risk factors. During treatment four pts (4; 6%) developed hypertension and 26 pts (30%) worsened the preexisting hypertension. Median left ventricular ejection fraction were 64 and 63% at baseline and after treatment, respectively. CONCLUSION: AA appears to be safe in pts with cardiovascular comorbidities or CAD risk factors.

Neutrophil-lymphocyte ratio kinetics in patients with advanced solid tumours on phase I trials of PD-1/PD-L1 inhibitors.

BACKGROUND: Although the neutrophil-lymphocyte ratio (NLR) is prognostic in many oncological settings, its significance in the immunotherapy era is unknown. Mechanistically, PD-1/PD-L1 inhibitors may alter NLR. We sought to characterise NLR kinetics in patients with advanced solid tumours treated with PD-1/PD-L1 inhibitors. METHODS: Electronic records of patients treated with PD-1/PD-L1 inhibitors on phase I trials across three sites were reviewed. A high NLR (hNLR) was predefined as >5. Univariate logistic regression models were used for toxicity, response analyses and Cox models for overall survival (OS) and progression-free survival analyses. Landmark analyses were performed (cycle two, three). Longitudinal analysis of NLR was performed utilising a mixed effect regression model. RESULTS: The median OS for patients with hNLR was 8.5 months and 19.4 for patients with low NLR, (hazard ratio [HR] = 1.85, 95% confidence interval [CI] 1.15-2.96, p = 0.01). On landmark analysis, hNLR was significantly associated with inferior OS at all time points with a similar magnitude of effect over time (p < 0.05). On multivariate analysis, NLR was associated with OS (HR 1.06, 95% CI 1.01-1.11, p = 0.01). NLR did not correlate with increased immune toxicity. Longitudinally, NLR correlated with response: NLR decreased by 0.09 (95% CI: -0.15 to -0.02; p = 0.01) per month in responders compared with non-responders. CONCLUSIONS: hNLR at baseline and during treatment is adversely prognostic in patients with advanced malignancies receiving PD-1/PD-L1 blockade. Importantly, NLR reduced over time in responders to immunotherapy. Taken together, these data suggest that baseline and longitudinal NLR may have utility as a unique biomarker to aid clinical decision-making in patients receiving immunotherapy.

Investigational ErbB-2 tyrosine kinase inhibitors for the treatment of breast cancer.

INTRODUCTION: ErbB2 overexpression and/or gene amplification is present in 20% of all breast cancers and characterizes an aggressive form of this disease. Despite the availability of several active drugs that have yielded substantial survival improvements, most patients with ErbB2-positive metastatic disease will develop tumor progression, either because of primary or acquired resistance. Therefore, research has focused on drugs that can more efficiently interfere with ErbB2 and with other members of the epidermal growth factor receptor family. AREAS COVERED: This review focuses on those investigational drugs that inhibit ErbB2 tyrosine kinase activity (TKIs) for treating breast cancer. EXPERT OPINION: ErbB-targeting TKIs show encouraging activity in patients with ErbB-positive tumors that are resistant to conventional ErbB-therapies (mostly trastuzumab), confirming pre-clinical observations. Efficient interference with the ErbB-network signaling implies also a potential use in ErbB2-normal tumors, where the phenotype is sustained by ErbB-aberrant signaling. Finally, early data suggests that ErbB-targeting TKIs could be active in treating patients with activating ErbB2 mutations. Ongoing and future research efforts should elucidate what is, according to the peculiarities of these compounds, their positioning in the treatment of women with breast cancer.

Breast cancer in BRCA mutation carriers: medical treatment.

About 10% of breast cancers are associated with the inheritance of autosomal dominant breast cancer susceptibility alleles BRCA1 and BRCA2. Until recently, the medical management of BRCA mutation-associated breast cancer has not differed from that of the sporadic breast cancer counterpart. However, there is mounting evidence that this molecular alteration confers sensitivity or resistance to systemic therapies that can be exploited in terms of medical management. For example, studies support the use of platinum salts chemotherapy in BRCA mutated cancers. Moreover, a number of targeted therapies are showing activity in BRCA mutation carriers. Above all, BRCA defective tumor cells are particularly sensitive to Poly(ADP-ribose) polymerase (PARP) inhibitors. This review will summarize the state of the art of the medical treatment of breast cancer in BRCA mutation carriers, with a particular focus on chemotherapies and targeted therapies.

Clinical utility of exemestane in the treatment of breast cancer.

Breast cancer is the most prevalent cancer in women, causing a significant mortality worldwide. Different endocrine strategies are available for the treatment of hormone-sensitive breast cancer, including antiestrogen tamoxifen and fulvestrant, as well as third-generation aromatase inhibitors (AIs), such as letrozole, anastrozole, and exemestane. In this review, we will focus on exemestane, its clinical use, and its side effects. Exemestane is a steroidal third-generation AI now used in all treatment settings for breast cancer. In the metastatic disease, it has been extensively investigated as the first-, second-, and further-line treatment and it is now registered for the treatment of postmenopausal women with advanced estrogen-receptor-positive breast cancer whose disease has progressed following antiestrogen therapy. A potential lack of cross-resistance with nonsteroidal AIs has been described, giving additional therapeutic opportunities in sequences of endocrine agents. Exemestane is also approved for the adjuvant treatment of postmenopausal early breast cancer, either as upfront monotherapy for 5 years, as a switch following 2-3 years of tamoxifen, or as extended therapy beyond 5 years of adjuvant treatment. New promising data also showed a beneficial effect in young premenopausal early breast cancer patients, when administered together with ovarian suppression. Interesting results have also emerged when exemestane has been investigated as neodjuvant treatment as well as preventive agent in healthy women at high risk for breast cancer. Exemestane is generally well tolerated, with a side effect profile similar to that of other AIs, including menopausal symptoms, arthralgia, and bone loss. In conclusion, exemestane can be considered an effective and well-tolerated endocrine treatment option for all stages of breast cancer.

Linifanib: current status and future potential in cancer therapy.

Angiogenesis is one of the major mechanisms controlling tumor proliferation and metastatic spreading. Targeting of pro-angiogenic factors and their downstream effectors represents an appealing therapeutic option in the treatment of different cancer types. Linifanib (ABT-869) is a novel tyrosine-kinase inhibitor (TKI) inhibitor and its anti-angiogenic activity has been explored in numerous clinical trials. Here, we review preclinical development of linifanib focusing on its pharmacodynamic and pharmacokinetic characteristics and briefly summarize its evaluation in clinical trials. Linifanib selectively targets VEGFR and PDGFR and has low off-target inhibitory activity. Preclinical and early-phase trials have been showing promising efficacy results However, although signals of anti-tumor activity have been proven in some malignancies, linifanib late-phase development has been facing some challenges due to limited efficacy and increased toxicities. New strategies aimed at finding biomarkers of response and minimizing toxicities are needed to allow the further development of a promising compound.

Buparlisib , an oral pan-PI3K inhibitor for the treatment of breast cancer.

INTRODUCTION: Deregulation of the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) intracellular signaling pathway is common in breast cancer (BC) and has been found to be potentially implicated in resistance to endocrine and anti-HER2 therapies. Targeting the PI3K/Akt/mTOR pathway may remove this inhibition and restore sensitivity to these compounds. Buparlisib (BKM120) is a potent oral pan-class I PI3K inhibitor that is being extensively evaluated in multiple tumor types. AREAS COVERED: This review briefly summarizes the pharmacodynamics and pharmacokinetics of buparlisib, focusing on preclinical and clinical data in BC and on ongoing randomized trials. EXPERT OPINION: Overall, buparlisib is a safe and tolerable drug and, despite its peculiar toxicity profile, it is suitable for studies in combination with other anticancer agents in BC. Early-phase clinical trials in BC have provided evidence of antitumor activity. Several trials are being conducted in all the biological subsets of BC, including combinations with endocrine therapy, anti-HER2 agents, PARP-inhibitors and chemotherapy. While clinical results are eagerly awaited, biological material suitable for both genomic and non-genomic analyses is being collected. The authors expect an intense investigation of the potential biomarkers that explain response or resistance to buparlisib and inspire strategies to rationally explore the therapeutic potential of this drug.

2013 San Antonio Breast Cancer Symposium.

The San Antonio Breast Cancer Symposium is considered by researchers and physicians involved in breast cancer management as one of the most important international events on the subject. A dense program of plenary presentations of novel findings, main lectures, poster discussions and displays, it encompasses all the aspects of the rapidly evolving field of breast cancer research and treatment. This article briefly summarises some of the presentations that are expected to have an impact on the medical treatment of breast cancer.