Highly favorable outcome in BRCA-mutated metastatic breast cancer patients receiving high-dose chemotherapy and autologous hematopoietic stem cell transplantation

Real-world clinical outcomes of patients with BRCA-mutated, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer: a CancerLinQ® study

Purpose

To investigate real-world clinical outcomes in patients with BRCA-mutated (BRCAm), HER2-negative metastatic breast cancer (mBC) according to BRCA and hormone receptor (HR) status.

Methods

Patients diagnosed with HER2-negative mBC between 01 January 2010 and 31 December 2018 were retrospectively identified from the American Society of Clinical Oncology’s CancerLinQ Discovery® database. Time to first subsequent therapy or death (TFST) from date of mBC diagnosis and start of first-line treatment for mBC and overall survival (OS) from date of mBC diagnosis were investigated according to BRCA status (BRCAm, BRCA wild type [BRCAwt] or unknown BRCA [BRCAu]) and HR status (positive/triple negative breast cancer [TNBC]). Follow-up continued until 31 August 2019 (i.e. minimum of 8 months).

Results

3744 patients with HER2-negative mBC were identified (BRCAwt, n = 460; BRCAm, n = 83; BRCAu, n = 3201) (HR-positive, n = 2738). Median (Q1, Q3) age was 63.0 (54.0, 73.0) years. Median (95% confidence interval [CI]) TFST (months) from mBC diagnosis was as follows: HR-positive, 7.7 (5.0, 11.2), 8.3 (6.6, 10.2) and 9.4 (8.7, 10.1); TNBC, 5.4 (3.9, 12.4), 5.6 (4.7, 6.6) and 5.4 (5.0, 6.2) for BRCAm, BRCAwt and BRCAu, respectively. Median (95% CI) OS (months) was as follows: HR-positive, 41.1 (31.5, not calculable), 55.1 (43.5, 65.5) and 33.0 (31.3, 34.8); TNBC, 13.7 (11.1, not calculable), 14.4 (10.7, 17.0) and 11.7 (10.3, 12.8) for BRCAm, BRCAwt and BRCAu, respectively.

Conclusion

When stratified by HR status, TFST and OS were broadly similar for patients with HER2-negative mBC, irrespective of BRCA status. Further global real-world studies are needed to study outcomes of this patient population.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-022-06541-3.

Cytotoxic and targeted therapy for BRCA1/2-driven cancers

Tumors arising in BRCA1/2 germline mutation carriers usually demonstrate somatic loss of the remaining BRCA1/2 allele and increased sensitivity to platinum compounds, anthracyclines, mitomycin C and poly (ADP-ribose) polymerase inhibitors (PARPi). Exposure to conventional platinum-based therapy or PARPi results in the restoration of BRCA1/2 function and development of resistance to systemic therapy, therefore, there is a need for other treatment options. Some studies suggested that the use of specific drug combinations or administration of high-dose chemotherapy may result in pronounced tumor responses. BRCA1/2-driven tumors are characterized by increased immunogenicity; promising efficacy of immune therapy has been demonstrated in a number of preclinical and clinical investigations. There are outstanding issues, which require further consideration. Platinum compounds and PARPi have very similar mode of antitumor action and are likely to render cross-resistance to each other, so their optimal position in cancer treatment schemes may be a subject of additional studies. Sporadic tumors with somatically acquired inactivation of BRCA1/2 or related genes resemble hereditary neoplasms with regard to the spectrum of drug sensitivity; the development of user-friendly BRCAness tests presents a challenge. Many therapeutic decisions are now based on the BRCA1/2 status, so the significant reduction of the turn-around time for predictive laboratory assays is of particular importance.

Mechanisms of acquired resistance of BRCA1/2-driven tumors to platinum compounds and PARP inhibitors

Molecular pathogenesis of tumors arising in BRCA1/2 germ-line mutation carriers usually includes somatic inactivation of the remaining allele of the involved gene. Consequently, BRCA1/2-driven cancers are sensitive to platinum-based therapy and poly (ADP-ribose) polymerase inhibitors (PARPi). Long-term exposure to these drugs may result in the emergence of secondary BRCA1/2 mutations, which restore the open-reading frame of the affected allele. This platinum/PARPi cross-resistance mechanism applies both for BRCA1 and BRCA2 genes and has been repeatedly validated in various laboratory models and multiple clinical studies. There are some other routes associated with the partial rescue of BRCA1/2 function or the development of BRCA1/2-independent pathways for genomic maintenance; however, their actual clinical relevance remains to be established. In addition, studies on the short-term neoadjuvant therapy for ovarian cancer revealed that even chemonaive BRCA1-driven tumors contain a small proportion of BRCA1-proficient cells. These pre-existing cells with retained BRCA1 heterozygosity rapidly repopulate the tumor mass during platinum exposure, but become outcompeted by BRCA1-deficient cells during therapy holidays. Understanding of the platinum/PARPi resistance pathways has led to the development of novel therapeutic approaches, which aim to improve the management of BRCA1/2-related cancers and are currently undergoing preclinical and clinical evaluation.

Mechanisms of acquired tumor drug resistance

Systemic therapy often results in the reduction of tumor size but rarely succeeds in eradicating all cancer cells. Drug efflux, persistence of cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT) and down-regulation of apoptosis are the most known general causes of therapy failure. Tumor escape from targeted compounds often involves pathway-specific mechanisms, which result in the restoration of the affected signaling cascade. The acquisition of drug resistance is mediated by mutations, changes in gene expression, alternative splicing, post-translational protein modifications, etc. Development of resistance to therapy may not necessary involve the emergence of new tumor clones: multiple studies demonstrate that even chemonaive neoplasms already have a small population of cells, which are capable of surviving therapeutic pressure and facilitating the disease progression. Use of combinations of cancer drugs, sequential therapy, adaptive therapy and topical ablation of drug-resistant malignant lumps may help to prolong the time to treatment failure. Many studies on mechanisms of drug resistance rely on the use of cell cultures and animal models. The development of approaches that allow efficient monitoring of the evolution of tumor phenotype in clinical setting presents a challenge.

Efficacy of Neoadjuvant Therapy With Cisplatin Plus Mitomycin C in BRCA1-Mutated Ovarian Cancer

OBJECTIVES

Cisplatin and mitomycin C exert high activity towards BRCA1-deficient cells. This study aimed to evaluate the efficacy of a combination of these drugs in hereditary BRCA1-associated ovarian cancer (OC).

METHODS

Twelve OC patients, who could not be treated by primary debulking surgery owing to extensive tumor spread, were given neoadjuvant cisplatin (100 mg/m) and mitomycin C (10 mg/m) every 4 weeks for 3 (n = 9), 2 (n = 2), or 4 (n = 1) cycles.

RESULTS

The decrease of tumor burden and complete surgical cytoreduction were achieved in all patients. Pathologic complete response, defined as the absence of tumor cells in surgically removed tissues, was observed in 2 (17%) of 12 cases. Retrospective analysis of 62 OC in BRCA1 mutation carriers subjected to conventional neoadjuvant chemotherapy schemes revealed 36 objective tumor responses (58%) and 37 instances (60%) of complete cytoreductive surgery; however, none of these patients demonstrated pathologic complete response.

CONCLUSIONS

The combination of cisplatin plus mitomycin C showed promising results in BRCA1-driven OC and therefore deserves further clinical evaluation.

Indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2019

This is the seventh special EBMT report on the indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders. Our aim is to provide general guidance on transplant indications according to prevailing clinical practice in EBMT countries and centres. In order to inform patient decisions, these recommendations must be considered together with the risk of the disease, the risk of the transplant procedure and the results of non-transplant strategies. In over two decades since the first report, the EBMT indications manuscripts have incorporated changes in transplant practice coming from scientific and technical developments in the field. In this same period, the establishment of JACIE accreditation has promoted high quality and led to improved outcomes of patient and donor care and laboratory performance in transplantation and cellular therapy. An updated report with operating definitions, revised indications and an additional set of data with overall survival at 1 year and non-relapse mortality at day 100 after transplant in the commonest standard-of-care indications is presented. Additional efforts are currently underway to enable EBMT member centres to benchmark their risk-adapted outcomes as part of the Registry upgrade Project 2020 against national and/or international outcome data.

Targeting BRCA Deficiency in Breast Cancer: What are the Clinical Evidences and the Next Perspectives?

Breast cancers (BC) associated with germline mutations of BRCA1/2 represent 3–5% of cases. BRCA1/2-associated BC have biological features leading to genomic instability and potential sensitivity to DNA damaging agents, including poly(ADP-ribose) polymerase (PARP) and platinum agents. In this review, we will summarize clinical trials of chemotherapy and PARP inhibitors (PARPi), alone or in combination, at the early or late stage of BRCA1/2-associated BC. We will also present the mechanisms of resistance to PARPi as well as the new therapeutic strategies of association with PARPi. Finally, we will discuss under which conditions the use of DNA damaging agents can be extended to the BRCA1/2-wild type population, the BRCAness concept.

Systemic Treatment Strategies for Patients with Hereditary Breast Cancer Syndromes

Hereditary breast cancer syndromes are associated with an increased risk of breast cancer and constitute a unique patient population, making up approximately 5%-10% of breast cancer cases in the United States. By virtue of the germline mutations that define these syndromes, invasive breast cancers in these patients have unique mechanisms that can be rationally targeted for therapeutic opportunities distinct from standard of care treatments in nongermline mutation associated breast cancers. This review intends to describe existing data on several of the most common hereditary breast cancer syndromes, including BRCA-related breast cancer syndrome, Li-Fraumeni syndrome, Cowden syndrome, Peutz-Jeghers syndrome, and hereditary diffuse gastric cancer syndrome, specifically focusing on rational therapeutics utilized in these distinct patient subgroups and completed or ongoing clinical trials evaluating their efficacy. By exploiting the distinct biologic features associated with these syndromes, tailored treatment strategies have the potential for improved efficacy and lower toxicity. Knowledge of the emergence of these targeted cancer therapies is critical for appropriate management in these patients, extending beyond treatment to highlight the need for appropriate genetic screening to allow for early recognition of these patients and therefore appropriate treatment.

IMPLICATIONS FOR PRACTICE

Molecular testing allows for identification of germline mutations that place individuals at high risk for breast cancer and that are associated with distinct histopathology and molecular characteristics that define the invasive breast cancer cases that these patients develop. These unique characteristics may ultimately provide rational targets for systemic treatments with improvements in both morbidity and efficacy. Identification of patients with these germline mutations is important for not only appropriate screening and prophylaxis, but knowledge of therapies specifically targeting several of the most common hereditary breast cancer syndromes is essential to ensure appropriate treatment of invasive breast cancers in these patients.

[Impact of Her2 and BRCA1/2 status in high-dose chemotherapy and autologous stem cells transplantation in the treatment of breast cancer: The Institut Paoli Calmettes' experience]

INTRODUCTION

Studies evaluating chemotherapy high dose chemotherapy with autologous haematopoietic stem cell transplantation (HDC-ACSH) in the treatment of metastatic (MBC), locally advanced (LABC) and inflammatory (IBC) breast cancer have in common lack of biomarker information, in particular the HER2 status.

PATIENTS AND METHODS

All consecutive female patients treated for breast cancer with HDC and AHSCT at Institut Paoli Calmettes between 2003 and 2012 were included. Patients were categorized in three subtypes based on hormonal receptor (HR) and HER2 status of the primary tumor: luminal, (HR+/HER2-), HER2 (HER2+, any HR) and triple negative (TN) (HER2- and HR-). The main objective was the analysis of overall survival (OS) according to the IHC subtypes.

RESULTS

Three hundred and seventy-seven patients were included. For MBC, the TN subtype appeared to have the worst prognosis with a median OS of 19.68 months (95 % CI 11.76-44.4) compared to 44.64 months (95 % CI 40.32-67.56) for the luminal subtype and a median OS not reached for the HER2 subtype (P<0.01). For IBC, HER2 subgroup appeared to have the best prognosis with a 5-year OS of 89 % (95 % CI 64-97) compared to 57 % (95 % CI 33-76) for the TN subgroup (HR 5.38, 95 % CI 1.14-25.44; P=0.034). For CSLA, luminal subgroup appeared to have the best prognosis with a 5-year OS of 92 % (95 % CI 71-98) against 75 % (95 % CI 46-90) for HER 2 subtype and 70 % (95 %CI 97-88) for TN subtype (P=0.301).

CONCLUSION

The HDC-ACSH does not change the prognosis value of IHC subtype in breast cancer patients.