Incidence of HER2-expressing brain metastases in patients with HER2-null breast cancer: a matched case analysis.

The HER2-directed antibody-drug conjugate trastuzumab deruxtecan is active against lower levels of HER2 expression than prior-generation therapies. The rate of HER2 expression in brain metastases among patients with initially HER2-null breast cancer is undefined, and receptor discordance in advanced breast cancer with brain metastases may underestimate CNS response potential in the absence of brain metastasis sampling. In this cohort study including 136 patients with 401 samples scored according to ASCO/CAP guidelines, 15/28 patients (54%) with HER2-null primary breast cancer have detectable HER2 expression in subsequently resected brain metastases, a significant discordant population.

Symptomatic Necrosis With Antibody-Drug Conjugates and Concurrent Stereotactic Radiotherapy for Brain Metastases.

This cohort study investigates whether brain metastases that manifest after stereotactic radiotherapy with concurrent antibody-drug conjugates are associated with an increased risk of symptomatic radiation necrosis.

New strategies for the treatment of breast cancer with leptomeningeal metastasis.

PURPOSE OF REVIEW: Leptomeningeal metastasis is a complication of metastatic breast cancer that has a rising incidence likely due to the increased availability of novel systemic therapies, which have improved survival with better extracranial disease control but with limited intracranial efficacy. A poor prognosis of less than 6 months has historically been associated with leptomeningeal metastasis and it is often an exclusion factor for enrollment in clinical trials. There are limited evidence-based data supporting use of therapeutics in leptomeningeal metastasis patients and recommendations are largely derived from retrospective reports and small prospective studies. However, in recent years, there has been a surge in effective modern therapeutics with promising intracranial activity. RECENT FINDINGS: The study aims to review the most recent updates in the management of leptomeningeal metastasis in breast cancer. We discuss the effectiveness and limitations of intrathecal administration, predictive biomarkers in the cerebrospinal fluid, proton radiation therapy and promising new systemic therapies such as antibody drug conjugates. SUMMARY: Ongoing development of clinical trials that allow inclusion of leptomeningeal metastasis are essential for establishing efficacy potential and discovering new treatment options in this population of great unmet need.

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.

Breast Cancer Brain Metastases: Achilles' Heel in Breast Cancer Patients' Care.

Brain metastases (BM) significantly affect the prognosis as well as the quality of life of breast cancer (BC) patients. Although advancements in neurosurgical and radiotherapy techniques improve local control and symptom management, BM remains associated with a poor prognosis. In addition, the efficacy of currently approved systemic therapies in central nervous system (CNS) compartment is still limited, especially after progression on local therapy. The blood-brain barrier (BBB) has been recognized as a mechanism of primary resistance to many chemotherapeutic agents and targeted therapies due to low drug penetration. Other mechanisms of primary and secondary resistance are still unclear and may vary across the BC subtypes. New small molecules have demonstrated efficacy in BM, in particular for the HER2-positive subtype, with a benefit in survival. A new era has begun in the field of BM, and many trials specifically designed for this population are currently ongoing. The BC research community needs to address this call with the final aim of improving the efficacy of systemic therapy in CNS compartment and ultimately preventing the occurrence of BM.

Randomized Phase II Trial of Proton Craniospinal Irradiation Versus Photon Involved-Field Radiotherapy for Patients With Solid Tumor Leptomeningeal Metastasis.

PURPOSE: Photon involved-field radiotherapy (IFRT) is the standard-of-care radiotherapy for patients with leptomeningeal metastasis (LM) from solid tumors. We tested whether proton craniospinal irradiation (pCSI) encompassing the entire CNS would result in superior CNS progression-free survival (PFS) compared with IFRT. PATIENTS AND METHODS: We conducted a randomized, phase II trial of pCSI versus IFRT in patients with non-small-cell lung cancer and breast cancers with LM. We enrolled patients with other solid tumors to an exploratory pCSI group. For the randomized groups, patients were assigned (2:1), stratified by histology and systemic disease status, to pCSI or IFRT. The primary end point was CNS PFS. Secondary end points included overall survival (OS) and treatment-related adverse events (TAEs). RESULTS: Between April 16, 2020, and October 11, 2021, 42 and 21 patients were randomly assigned to pCSI and IFRT, respectively. At planned interim analysis, a significant benefit in CNS PFS was observed with pCSI (median 7.5 months; 95% CI, 6.6 months to not reached) compared with IFRT (2.3 months; 95% CI, 1.2 to 5.8 months; P < .001). We also observed OS benefit with pCSI (9.9 months; 95% CI, 7.5 months to not reached) versus IFRT (6.0 months; 95% CI, 3.9 months to not reached; P = .029). There was no difference in the rate of grade 3 and 4 TAEs (P = .19). In the exploratory pCSI group, 35 patients enrolled, the median CNS PFS was 5.8 months (95% CI, 4.4 to 9.1 months) and OS was 6.6 months (95% CI, 5.4 to 11 months). CONCLUSION: Compared with photon IFRT, we found pCSI improved CNS PFS and OS for patients with non-small-cell lung cancer and breast cancer with LM with no increase in serious TAEs.

Treatment With Etirinotecan Pegol for Patients With Metastatic Breast Cancer and Brain Metastases: Final Results From the Phase 3 ATTAIN Randomized Clinical Trial.

Importance: Patients with breast cancer and brain metastases (BM) have a poor prognosis and high clinical need for novel treatments; however, historically, studies have often excluded these patients. Although the BEACON study did not meet its primary end point, treatment with etirinotecan pegol vs chemotherapy of the physician's choice for patients with advanced breast cancer demonstrated a significant improvement in overall survival (OS) for the prespecified patient subgroup with preexisting, pretreated, and nonprogressive BM. Objective: To compare clinical outcomes in patients with BM treated with etirinotecan pegol vs chemotherapy of the physician's choice in a confirmatory trial. Design, Setting, and Participants: This study was a phase 3, open-label, randomized clinical trial (ATTAIN) in patients with metastatic breast cancer and a history of stable pretreated BM who experienced disease progression while receiving chemotherapy in the metastatic setting. The trial took place at 47 sites in 10 countries, and patients were enrolled between March 7, 2017, and November 6, 2019. Interventions: Patients were randomized to receive etirinotecan pegol, 145 mg/m2, every 21 days or chemotherapy (eribulin, ixabepilone, vinorelbine, gemcitabine, paclitaxel, docetaxel, or nab-paclitaxel). Main Outcomes and Measures: The primary end point was OS. Key secondary end points included progression-free survival, objective response rate, duration of response, and the clinical benefit rate. Results: A total of 178 female patients (9 [5.1%] Asian, 8 [4.5%] Black or African American, and 123 [69.1] White individuals) were randomized to receive treatment with etirinotecan pegol (92 [51.7%]; median [range] age, 53 [27-79] years) or chemotherapy (86 [48.3%]; median [range] age, 52 [24-77] years). Median OS was similar in both groups (etirinotecan pegol, 7.8 months; chemotherapy, 7.5 months; hazard ratio [HR], 0.90; 95% CI, 0.61-1.33; P = .60). Median progression-free survival for non-central nervous system metastases per blinded independent central review for etirinotecan pegol vs chemotherapy was 2.8 and 1.9 months (HR, 0.72; 95% CI, 0.45-1.16; P = .18) and 3.9 vs 3.3 months, respectively, for central nervous system metastases (HR, 0.59; 95% CI, 0.33-1.05; P = .07). Safety profiles between the groups were largely comparable. Conclusions and Relevance: The results of the ATTAIN randomized clinical trial found no statistically significant difference in outcomes between treatment with etirinotecan pegol and chemotherapy in patients with BM. However, this study represents one of the largest published trials dedicated to patients with breast cancer and BM and may help to inform further research. Trial Registration: ClinicalTrials.gov Identifier: NCT02915744.

Incidence of brain metastases in patients with early HER2-positive breast cancer receiving neoadjuvant chemotherapy with trastuzumab and pertuzumab.

The addition of pertuzumab (P) to trastuzumab (H) and neoadjuvant chemotherapy (NAC) has decreased the risk of distant recurrence in early stage HER2-positive breast cancer. The incidence of brain metastases (BM) in patients who achieved pathological complete response (pCR) versus those who do not is unknown. In this study, we sought the incidence of BM in patients receiving HP-containing NAC as well as survival outcome. We reviewed the medical records of 526 early stage HER2-positive patients treated with an HP-based regimen at Memorial Sloan Kettering Cancer Center (MSKCC), between September 1, 2013 to November 1, 2019. The primary endpoint was to estimate the cumulative incidence of BM in pCR versus non-pCR patients; secondary endpoints included disease free-survival (DFS) and overall survival (OS). After a median follow-up of 3.2 years, 7 out of 286 patients with pCR had a BM while 5 out of 240 non-pCR patients had a BM. The 3-year DFS was significantly higher in the pCR group compared to non-pCR group (95% vs 91 %, p = 0.03) and the same trend was observed for overall survival. In our cohort, despite the better survival outcomes of patients who achieved pCR, we did not observe appreciable differences in the incidence of BM by pCR/non-pCR status. This finding suggests that the BM incidence could not be associated with pCR. Future trials with new small molecules able to cross the blood brain barrier should use more specific biomarkers rather than pCR for patients' selection.

A phase I trial of sorafenib with whole brain radiotherapy (WBRT) in breast cancer patients with brain metastases and a correlative study of FLT-PET brain imaging.

PURPOSE: Sorafenib has demonstrated anti-tumor efficacy and radiosensitizing activity preclinically and in breast cancer. We examined sorafenib in combination with whole brain radiotherapy (WBRT) and explored the [18F] 3'deoxy-3'-fluorothymidine (FLT)-PET as a novel brain imaging modality in breast cancer brain metastases. METHODS: A phase I trial of WBRT + sorafenib was conducted using a 3 + 3 design with safety-expansion cohort. Sorafenib was given daily at the start of WBRT for 21 days. The primary endpoints were to determine a maximum tolerated dose (MTD) and to evaluate safety and toxicity. The secondary endpoint was CNS progression-free survival (CNS-PFS). MacDonald Criteria were used for response assessment with a correlative serial FLT-PET imaging study. RESULTS: 13 pts were evaluable for dose-limiting toxicity (DLT). DLTs were grade 4 increased lipase at 200 mg (n = 1) and grade 3 rash at 400 mg (n = 3). The MTD was 200 mg. The overall response rate was 71%. Median CNS-PFS was 12.8 months (95%CI: 6.7-NR). A total of 15 pts (10 WBRT + sorafenib and 5 WBRT) were enrolled in the FLT-PET study: baseline (n = 15), 7-10 days post WBRT (FU1, n = 14), and an additional 12 week (n = 9). A decline in average SUVmax of ≥ 25% was seen in 9/10 (90%) of WBRT + sorafenib patients and 2/4 (50%) of WBRT only patients. CONCLUSIONS: Concurrent WBRT and sorafenib appear safe at 200 mg daily dose with clinical activity. CNS response was favorable compared to historical controls. This combination should be considered for further efficacy evaluation. FLT-PET may be useful as an early response imaging tool for brain metastases. TRIAL AND CLINICAL REGISTRY: Trial registration numbers and dates: NCT01724606 (November 12, 2012) and NCT01621906 (June 18, 2012).

Real-world treatment patterns and outcomes of abemaciclib for the treatment of HR+, HER2- metastatic breast cancer.

OBJECTIVE: This retrospective observational study described baseline characteristics, real-world treatment patterns, and outcomes among patients with metastatic breast cancer treated with abemaciclib in the United States. METHODS: De-identified electronic health record-derived data were used to describe patients who began abemaciclib treatment on or after 30 June 2016 and ≥4 months before data cutoff (31 December 2018). Real-world response (rwR) and real-world progression assessments were abstracted from clinical documentation. Descriptive statistics were used to calculate the real-world best response. The Kaplan-Meier method estimated real-world time to first response (rwTTFR) and real-world progression-free survival (rwPFS). RESULTS: The median age of 118 female patients at abemaciclib initiation was 66.5 years (interquartile range, 57.0, 73.0). The breakdown of patients who received abemaciclib in first, second, third, or later lines was 28.8%, 21.2%, 20.3%, and 29.7%, respectively. Patients received abemaciclib as monotherapy (12.7%) or in combination with endocrine therapy: fulvestrant (59.3%); aromatase inhibitor (22.9%); aromatase inhibitor and fulvestrant (5.1%). There were 68 patients (57.6%) with ≥1 rwR assessment: 41.2% with a real-world complete response or real-world partial response. Median rwTTFR was 3.6 months (95% confidence interval, 3.5, 5.2). Twelve-month rwPFS probability was 61.7%. CONCLUSIONS: This study represents utilization and outcomes associated with abemaciclib approximately 1 year following FDA approval. Treatment patterns demonstrated heterogeneity and, as in clinical trials, patients appeared to benefit from abemaciclib treatment in the real world. More research investigating outcomes associated with abemaciclib treatment is needed, with larger samples and longer follow-up to enable closer evaluation by subgroup, regimen, and line of therapy.

Clinical trial of proton craniospinal irradiation for leptomeningeal metastases.

BACKGROUND: Leptomeningeal metastases (LM) are associated with limited survival and treatment options. While involved-field radiotherapy is effective for local palliation, it lacks durability. We evaluated the toxicities of proton craniospinal irradiation (CSI), a treatment encompassing the entire central nervous system (CNS) compartment, for patients with LM from solid tumors. METHODS: We enrolled patients with LM to receive hypofractionated proton CSI in this phase I prospective trial. The primary endpoint was to describe treatment-related toxicity, with dose-limiting toxicity (DLT) defined as any radiation-related grade 3 non-hematologic toxicity or grade 4 hematologic toxicity according to the Common Terminology Criteria for Adverse Events that occurred during or within 4 weeks of completion of proton CSI. Secondary endpoints included CNS progression-free survival (PFS) and overall survival (OS). RESULTS: We enrolled 24 patients between June 2018 and April 2019. Their median follow-up was 11 months. Twenty patients were evaluable for protocol treatment-related toxicities and 21 for CNS PFS and OS. Two patients in the dose expansion cohort experienced DLTs consisted of grade 4 lymphopenia, grade 4 thrombocytopenia, and/or grade 3 fatigue. All DLTs resolved without medical intervention. The median CNS PFS was 7 months (95% CI: 5-13) and the median OS was 8 months (95% CI: 6 to not reached). Four patients (19%) were progression-free in the CNS for more than 12 months. CONCLUSION: Hypofractionated proton CSI using proton therapy is a safe treatment for patients with LM from solid tumors. We saw durable disease control in some patients.

The Evolution of Clinical Trials in Metastatic Breast Cancer: Design Features and Endpoints That Matter.

The evolution of thought in assessing benefit in clinical trials of systemic therapy for metastatic breast cancer (MBC) is well documented, with most agents garnering regulatory approval based either on an advantage in overall survival (OS), time to progression (TTP), or progression-free survival (PFS) over an existing standard of care or objective response rate (ORR). Previous guidance for industry on clinical trial endpoints for the approval of cancer drugs and biologics was provided by the U.S. Food and Drug Administration (FDA) in 2007 and recently updated in 2018. The more recent FDA guidance recognizes that advances in science are facilitating the development of oncology products, which "may also result in the identification of additional endpoints that may be used to support approval of oncology products." This article critically addressed the evolution of thought on the advancement of clinical trials in MBC, from various stakeholder perspectives. Despite the term "stakeholder," the objective of all co-authors and parties concerned is to promote and inform the optimal design, conduct, and reporting of clinical trials for women with advanced breast cancer toward improving and extending lives. This article provides an overview of the evolving perspectives on this issue from the physician, regulatory agency, and patient and/or advocate points of view.

ATTAIN: Phase III study of etirinotecan pegol versus treatment of physician's choice in patients with metastatic breast cancer and brain metastases.

The increasing incidence of breast cancer brain metastases is a major clinical problem with its associated poor prognosis and limited treatment options. The long-acting topoisomerase-1 inhibitor, etirinotecan pegol, was designed to preferentially accumulate in tumor tissue including brain metastases, providing sustained cytotoxic SN38 levels. Motivated by improved survival findings from subgroup analyses from the Phase III BEACON trial, this ongoing randomized, Phase III trial compares etirinotecan pegol to drugs commonly used for advanced breast cancer in patients with stable, treated breast cancer brain metastases who have been previously treated with an anthracycline, taxane and capecitabine. The primary end point is overall survival. Secondary end points include objective response rate, progression-free survival and time to CNS disease progression or recurrence in patients with/without CNS lesions present at study entry. Trial registration number: NCT02915744.

Phase I Study of Intermittent High-Dose Lapatinib Alternating with Capecitabine for HER2-Positive Breast Cancer Patients with Central Nervous System Metastases.

PURPOSE: Lapatinib and capecitabine cross the blood-tumor barrier in breast cancer brain metastasis but have modest clinical efficacy. Administration of high-dose tyrosine kinase inhibitor has been evaluated in brain metastases and primary brain tumors as a strategy to improve drug exposure in the central nervous system (CNS). We derived a rational drug scheduling of intermittent high-dose lapatinib alternating with capecitabine based on our preclinical data and Norton-Simon mathematical modeling. We tested this intermittent, sequential drug schedule in patients with breast cancer with CNS metastasis. PATIENTS AND METHODS: We conducted a phase I trial using an accelerated dose escalation design in patients with HER2-positive (HER2+) breast cancer with CNS metastasis. Lapatinib was given on day 1-3 and day 15-17 with capecitabine on day 8-14 and day 22-28 on an every 28-day cycle. Lapatinib dose was escalated, and capecitabine given as a flat dose at 1,500 mg BID. Toxicity and efficacy were evaluated. RESULTS: Eleven patients were enrolled: brain only (4 patients, 36%), leptomeningeal (5 patients, 45%), and intramedullary spinal cord (2 patients, 18%). Grade 3 nausea and vomiting were dose-limiting toxicities. The MTD of lapatinib was 1,500 mg BID. Three patients remained on therapy for greater than 6 months. CONCLUSIONS: High-dose lapatinib is tolerable when given intermittently and sequentially with capecitabine. Antitumor activity was noted in both CNS and non-CNS sites of disease. This novel administration regimen is feasible and efficacious in patients with HER2+ breast cancer with CNS metastasis and warrants further investigation.

"A Tool, Not a Crutch": Patient Perspectives About IBM Watson for Oncology Trained by Memorial Sloan Kettering.

PURPOSE: IBM Watson for Oncology trained by Memorial Sloan Kettering (WFO) is a clinical decision support tool designed to assist physicians in choosing therapies for patients with cancer. Although substantial technical and clinical expertise has guided the development of WFO, patients' perspectives of this technology have not been examined. To facilitate the optimal delivery and implementation of this tool, we solicited patients' perceptions and preferences about WFO. METHODS: We conducted nine focus groups with 46 patients with breast, lung, or colorectal cancer with various treatment experiences: neoadjuvant/adjuvant chemotherapy, chemotherapy for metastatic disease, or systemic therapy through a clinical trial. In-depth qualitative and quantitative data were collected and analyzed to describe patients' attitudes and perspectives concerning WFO and how it may be used in clinical care. RESULTS: Analysis of the qualitative data identified three main themes: patient acceptance of WFO, physician competence and the physician-patient relationship, and practical and logistic aspects of WFO. Overall, participant feedback suggested high levels of patient interest, perceived value, and acceptance of WFO, as long as it was used as a supplementary tool to inform their physicians' decision making. Participants also described important concerns, including the need for strict processes to guarantee the integrity and completeness of the data presented and the possibility of physician overreliance on WFO. CONCLUSION: Participants generally reacted favorably to the prospect of WFO being integrated into the cancer treatment decision-making process, but with caveats regarding the comprehensiveness and accuracy of the data powering the system and the potential for giving WFO excessive emphasis in the decision-making process. Addressing patients' perspectives will be critical to ensuring the smooth integration of WFO into cancer care.

Summary of head-to-head comparisons of patient risk classifications by the 21-gene Recurrence Score® (RS) assay and other genomic assays for early breast cancer.

Many genomic assays that assess recurrence risk in early breast cancer (EBC) are prognostic, but they differ in risk group stratification, which can affect clinical utility. Prospective outcomes of >60 K patients treated based on the 21-gene assay results have shown that chemotherapy may be safely omitted in EBC patents with low Recurrence Score (RS) results (RS < 18). Because of its extensive validation and wide clinical use, the RS assay is a common comparator in head-to-head studies with other assays. Published/presented studies of the RS assay performed on the same tumor samples with Breast Cancer Index (BCI), EndoPredict (EP) or EP+ clinical features (EPclin), MammaPrint (MMP) and/or Prosigna (ROR) assays were reviewed. Study findings were summarized descriptively.

National Cancer Institute Breast Cancer Steering Committee Working Group Report on Meaningful and Appropriate End Points for Clinical Trials in Metastatic Breast Cancer.

PURPOSE: To provide evidence-based consensus recommendations on choice of end points for clinical trials in metastatic breast cancer, with a focus on biologic subtype and line of therapy. METHODS: The National Cancer Institute Breast Cancer Steering Committee convened a working group of breast medical oncologists, patient advocates, biostatisticians, and liaisons from the Food and Drug Administration to conduct a detailed curated systematic review of the literature, including original reports, reviews, and meta-analyses, to determine the current landscape of therapeutic options, recent clinical trial data, and natural history of four biologic subtypes of breast cancer. Ongoing clinical trials for metastatic breast cancer in each subtype also were reviewed from ClinicalTrials.gov for planned primary end points. External input was obtained from the pharmaceutic/biotechnology industry, real-world clinical data specialists, experts in quality of life and patient-reported outcomes, and combined metrics for assessing magnitude of clinical benefit. RESULTS: The literature search yielded 146 publications to inform the recommendations from the working group. CONCLUSION: Recommendations for appropriate end points for metastatic breast cancer clinical trials focus on biologic subtype and line of therapy and the magnitude of absolute and relative gains that would represent meaningful clinical benefit.