Talazoparib Versus Chemotherapy in Patients with HER2-negative Advanced Breast Cancer and a Germline BRCA1/2 Mutation Enrolled in Asian Countries: Exploratory Subgroup Analysis of the Phase III EMBRACA Trial

Detection and analysis of the safety profile of talazoparib based on FAERS database

BACKGROUND

Talazoparib was approved for the treatment of breast cancer. However, the safety of talazoparib in a large population sample over an extended period remained uncertain. The objective of this study is to offer guidance for the secure utilization of talazoparib in clinical settings.

METHODS

Four algorithms were used to quantify the signals of talazoparib associated adverse events(AEs), using data from the food and drug administration adverse event reporting system(FAERS) between fourth quater of 2018 and second quater of 2023.

RESULTS

A total of 7,186,517 records were reported, with 737 indicating talazoparib as the primary suspected (PS) AEs. A total of 40 significant preferred terms (PTs) that adhere to the four algorithms were simultaneously retained. There is a possibility of experiencing unforeseen and noteworthy AEs, including embolism(0.46%), pulmonary embolism(1.06%), hyponatremia(0.46%), hypokalemia(0.40%), hematuria(0.33%), and pericardial effusion(0.26%). Most of the AEs related to talazoparib occurred within the initial month of starting the medication, with a median onset time of 79 days (IQR: 22-207 days).

CONCLUSION

Results of our study were consistent with clinical observations, and we also found potential new and unexpected AEs signals for talazoparib, suggesting prospective clinical studies were needed to confirm these results and illustrate their relationship. Our results may provide valuable evidence for further safety studies of talazoparib.

HR-positive/HER2-negative breast cancer arising in patients with or without BRCA2 mutation: different biological phenotype and similar prognosis

Background

BRCA2 plays a key role in homologous recombination. However, information regarding its mutations in Chinese patients with breast cancer remains limited.

Objectives

This study aimed to assess the clinicopathological characteristics of BRCA2 mutation breast cancer and explore the mutation's effect on hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer survival in China.

Design

This hospital-based cohort study prospectively included 629 women with breast cancer diagnosed from 2008 to 2023 at Zhejiang Cancer Hospital in China.

Methods

We compared the clinicopathological characteristics and metastatic patterns and analysed the invasive disease-free survival (iDFS), distant relapse-free survival (DRFS) and first-line progression-free survival (PFS1) of patients with HR-positive/HER2-negative breast cancer according to BRCA2 mutations.

Results

Among the 629 patients, 78 had BRCA2 mutations (12.4%) and 551 did not (87.6%). The mean age at diagnosis was lower in the BRCA2 mutation breast cancer group than in the non-mutation breast cancer group (38.91 versus 41.94 years, p = 0.016). BRCA2 mutation breast cancers were more likely to be lymph node-positive than non-mutation breast cancers (73.0% versus 56.6%, p = 0.037). The pathological grade was higher in 47.1% of BRCA2 mutation breast cancers than in 29.6% of non-mutation breast cancers (p = 0.014). The proportions of patients with BRCA2 mutations who developed contralateral breast cancer (19.2% versus 8.8%, p = 0.004), breast cancer in the family (53.8% versus 38.3%, p = 0.009) and ovarian cancer in the family (7.6% versus 2.4%, p = 0.022) were higher than those of patients without the mutation. The median follow-up time was 92.78 months. Multivariate analysis showed that BRCA2 mutation was not associated with poorer iDFS [hazard ratio = 0.9, 95% confidence interval (CI) = 0.64-1.27, p = 0.56] and poorer distant relapse-free survival (DRFS) (hazard ratio = 1.09, 95% CI = 0.61-1.93, p = 0.76). There was no significant difference between the two groups with regard to metastatic patterns in the advanced disease setting. In the first-line metastatic breast cancer setting, PFS1 expression was broadly similar between the two groups irrespective of chemotherapy or endocrine therapy.

Conclusion

HR-positive/HER2-negative breast cancer with BRCA2 mutations differs from those without mutations in clinical behaviour and reflects more aggressive tumour behaviour. Our results indicate that BRCA2 mutations have no significant effect on the survival of Chinese women with HR-positive/HER2-negative breast cancer.

Molecular Biology Mechanisms and Emerging Therapeutics of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is conventionally characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2), accounting for approximately 15-20% of all breast cancers. Compared to other molecular phenotypes, TNBC is typically associated with high malignancy and poor prognosis. Cytotoxic agents have been the mainstay of treatment for the past few decades due to the lack of definitive targets and limited therapeutic interventions. However, recent developments have demonstrated that TNBC has peculiar molecular classifications and biomarkers, which provide the possibility of evolving treatment from basic cytotoxic chemotherapy to an expanding domain of targeted therapies. This review presents a framework for understanding the current clinical experience surrounding molecular biology mechanisms in TNBC (Figure 1). Including immunotherapy, polymerase (PARP) and PI3K/AKT pathway inhibitors, antibody-drug conjugates, and androgen receptor (AR) blockade. Additionally, the role of miRNA therapeutics targeting TNBC and potential strategies targeting cancer stem cells (CSCs) are discussed and highlighted. As more and more treatments arise on the horizon, we believe that patients with TNBC will have a new sense of hope.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, staging and treatment of patients with metastatic breast cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, staging and treatment of patients with metastatic breast cancer (MBC) was published in 2021. A special, hybrid guidelines meeting was convened by ESMO and the Korean Society of Medical Oncology (KSMO) in collaboration with nine other Asian national oncology societies in May 2022 in order to adapt the ESMO 2021 guidelines to take into account the differences associated with the treatment of MBC in Asia. These guidelines represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with MBC representing the oncological societies of China (CSCO), India (ISMPO), Indonesia (ISHMO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO). The voting was based on the best available scientific evidence and was independent of drug access or practice restrictions in the different Asian countries. The latter were discussed when appropriate. The aim of these guidelines is to provide guidance for the harmonisation of the management of patients with MBC across the different regions of Asia, drawing from data provided by global and Asian trials whilst at the same time integrating the differences in genetics, demographics and scientific evidence, together with restricted access to certain therapeutic strategies.

Sustained delivery of PARP inhibitor Talazoparib for the treatment of BRCA-deficient ovarian cancer

Background

Ovarian cancer has long been known to be the deadliest cancer associated with the female reproductive system. More than 15% of ovarian cancer patients have a defective BRCA-mediated homologous recombination repair pathway that can be therapeutically targeted with PARP inhibitors (PARPi), such as Talazoparib (TLZ). The expansion of TLZ clinical approval beyond breast cancer has been hindered due to the highly potent systemic side effects resembling chemotherapeutics. Here we report the development of a novel TLZ-loaded PLGA implant (InCeT-TLZ) that sustainedly releases TLZ directly into the peritoneal (i.p.) cavity to treat patient-mimicking BRCA-mutated metastatic ovarian cancer (mOC).

Methods

InCeT-TLZ was fabricated by dissolving TLZ and PLGA in chloroform, followed by extrusion and evaporation. Drug loading and release were confirmed by HPLC. The in vivo therapeutic efficacy of InCeT-TLZ was carried out in a murine Brca2^-/-p53^R172H/-Pten^-/- genetically engineered peritoneally mOC model. Mice with tumors were divided into four groups: PBS i.p. injection, empty implant i.p. implantation, TLZ i.p. injection, and InCeT-TLZ i.p. implantation. Body weight was recorded three times weekly as an indicator of treatment tolerance and efficacy. Mice were sacrificed when the body weight increased by 50% of the initial weight.

Results

Biodegradable InCeT-TLZ administered intraperitoneally releases 66 μg of TLZ over 25 days. In vivo experimentation shows doubled survival in the InCeT-TLZ treated group compared to control, and no significant signs of toxicity were visible histologically in the surrounding peritoneal organs, indicating that the sustained and local delivery of TLZ greatly maximized therapeutic efficacy and minimized severe clinical side effects. The treated animals eventually developed resistance to PARPi therapy and were sacrificed. To explore treatments to overcome resistance, in vitro studies with TLZ sensitive and resistant ascites-derived murine cell lines were carried out and demonstrated that ATR inhibitor and PI3K inhibitor could be used in combination with the InCeT-TLZ to overcome acquired PARPi resistance.

Conclusion

Compared to intraperitoneal PARPi injection, the InCeT-TLZ better inhibits tumor growth, delays the ascites formation, and prolongs the overall survival of treated mice, which could be a promising therapy option that benefits thousands of women diagnosed with ovarian cancer.

Development of the PARP inhibitor talazoparib for the treatment of advanced BRCA1 and BRCA2 mutated breast cancer

INTRODUCTION

BRCA1 and BRCA2 (BRCA1/2) mutation breast cancers constitute an uncommon, but unique group of breast cancers that present at a younger age, and are underscored by genomic instability and accumulation of DNA damage. Talazoparib is a potent poly(ADP-ribose) polymerase (PARP) inhibitor that exploits impaired DNA damage response mechanisms in this population of patients and results in significant efficacy. Based on the results of the EMBRACA trial, talazoparib was approved for the treatment of patients with advanced germline BRCA1/2 mutant breast cancer.

AREAS COVERED

In this review, the authors highlight the relevant clinical trials of talazoparib, as well as, safety, tolerability, and quality of life considerations. They also examine putative response and resistance mechanisms, and rational combinatorial therapeutic strategies under development.

EXPERT OPINION

Talazoparib has been a major advance in the treatment of germline BRCA1/2 mutation breast cancer with both clinical efficacy and improvement in quality of life compared to standard cytotoxic chemotherapy. To date, the optimal sequencing of talazoparib administration in the metastatic setting has not yet been established. A deeper understanding of response and resistance mechanisms, and more broadly, the DNA repair pathway, will lead to additional opportunities in targeting this pathway and open up therapeutic indications to a broader patient population.