Trastuzumab deruxtecan (T-DXd) in patients with HER2+ metastatic breast cancer with brain metastases: A subgroup analysis of the DESTINY-Breast01 trial

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Background: Patients (pts) with HER2+ metastatic breast cancer (mBC) are at high risk of developing brain metastases (BMs), and treatment options are limited once BMs occur. T-DXd is an antibody-drug conjugate composed of an anti-HER2 antibody, a cleavable tetrapeptide-based linker, and a topoisomerase I inhibitor payload. On the basis of findings of the phase 2 DESTINY-Breast01 trial (NCT03248492), T-DXd was approved for the treatment of adult pts with HER2+ unresectable or mBC who have received ≥2 prior anti-HER2–based regimens (US and Europe) or had prior chemotherapy and are refractory to or intolerant of standard treatments (Japan). Here we describe a subgroup analysis from DESTINY-Breast01 in pts with a history of BMs. Methods: DESTINY-Breast01 is an ongoing, 2-part, multicenter, open-label, phase 2 trial of T-DXd in adult pts with HER2+ unresectable or mBC previously treated with trastuzumab emtansine. Pts with baseline BMs that were treated, asymptomatic, and did not require therapy to control symptoms were eligible for enrollment. All treatment to control symptoms had to be completed ≥60 days before randomization. An MRI of the brain every 6 wks was only required for pts with BMs at baseline. Brain lesions were considered non-target lesions, and thus collection of diameter measurements was not required. This analysis includes pts with a history of BMs at baseline who received T-DXd at the approved dose of 5.4 mg/kg every 3 wks. Results: Twenty-four pts with a history of BMs were included (data cutoff, August 1, 2019). In these pts, the objective response rate (ORR), median progression-free survival (mPFS), and median duration of response (mDoR) per independent central review with T-DXd 5.4 mg/kg were 58.3% (95% CI, 36.6%-77.9%), 18.1 mo (95% CI, 6.7-18.1 mo), and 16.9 mo (95% CI, 5.7-16.9 mo), respectively, and were comparable to those in the total pt population (N = 184) treated at 5.4 mg/kg in the DESTINY-Breast01 study (ORR, 60.9%; mPFS, 16.4 mo; mDoR, 14.8 mo; median follow-up, 11.1 mo). The pattern of disease progression was similar in pts with and without BMs with 8 of 24 pts having progressed (33%; 2 in the brain) in the BMs subgroup and 40 of 160 pts (25%; 2 in the brain) in the non-BMs subgroup, suggesting durable systemic disease control. Baseline diameters of BMs were available for 14 of 24 pts (radiotherapy prior to study enrollment was reported in 12 of 14). Among the pts with information available on baseline BM diameter, the central nervous system response rate per investigators was 50% (7 of 14 pts). Conclusions: T-DXd showed strong clinical activity in both the overall population of pts with HER2+ mBC and the subgroup of pts with BMs. The demonstrable response of BMs to treatment and durable clinical activity of T-DXd in pts with a history of BMs at baseline are promising and warrant further investigation. Clinical trial information: NCT03248492.

High-risk breast cancer genes at 8q22-24 and their role in over 5,000 patients evaluated with the 70-gene risk of recurrence assay

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Background: Previous studies have shown that CCNE2 expression is higher in patients’ cancers resistant to CDK4/6 inhibitors. Increased expression of CCNE2, MTDH, or TSPYL5, genes contained within the 70-gene risk of distant recurrence signature (70GS), has also been implicated in breast oncogenesis, poor prognosis, and chemoresistance. These genes are located on chromosome region 8q22.1, one of the most recurrently amplified regions out of all 70GS genes in breast tumors (Fatima et al. 2017). MYC, located on 8q24, is overexpressed in 40% of all breast cancers (BC). Here we examined the expression of CCNE2, MTDH, and TSPYL5 in relation to 70GS risk and the 80-gene molecular subtype signature (80GS), and their correlation with MYC expression in early stage BC patients. Methods: CCNE2, MTDH, TSPYL5, and MYC mRNA expression was measured in 5022 BC samples sent to Agendia (Irvine, CA) for 70GS and 80GS testing, which included FFPE microarray full-transcriptome data. 70GS was used to stratify patients into Ultra Low Risk (UL), Low Risk (LR), High Risk (HR), and Ultra High Risk (UH). Both 70GS and 80GS were used to classify patient samples into Luminal A, Luminal B, HER2, or Basal type. Wilcoxon rank sum test was used to assess expression differences. Results: The expression of CCNE2, MTDH, and TSPYL5 significantly correlated with each other and was higher in HR patients compared to LR patients (p < 0.001) and higher in UH patients compared to HR patients (p < 0.001). Expression of these genes was highest in Basal type tumors, 83% of which were UH, followed by Luminal B type tumors, and lowest in Luminal A type tumors. CCNE2 and MYC expression was elevated in LR compared to UL patients (p < 0.001 and p = 0.0043). There was no difference in MYC expression between HR vs. LR or UH vs. HR. Lastly, there was no association between the expression of 8q22.1 genes and MYC in any 70GS subgroup. Conclusions: Within the 70GS, CCNE2, MTDH, and TSPYL5 have similar expression patterns and when overexpressed may identify an UH cohort of BC. This observation, in addition to their physical proximity at 8q22.1 suggests a possible amplicon in this region. The highest expression of CCNE2, MTDH, and TSPYL5 associated with UH patients and is concordant with previous studies that support the role of these genes in BC metastasis. Furthermore, this analysis suggests MYC may not stratify patients based on metastatic potential. These data may be clinically relevant for stratifying patients in ongoing clinical trials evaluating response and resistance to targeted therapies in early stage BC.

Effect of exercise during adjuvant chemotherapy for breast cancer

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Background: In 2018, an estimated 266,120 women faced the challenge of living with breast cancer and approximately 40,920 died from their disease. Nearly 100% of these women experienced significant treatment related side effects that negatively impact quality of life (QOL). Exercise has repeatedly demonstrated to alleviate many of the side effects, improve QOL, and decrease cancer recurrence and mortality. In spite of this evidence, women do not maintain exercise during treatment for breast cancer. The purpose of this randomized controlled trial was to determine the effectiveness of exercising the day chemotherapy is administered on 1) the persistence with an exercise program, 2) side effects, and 3) QOL. Methods: Eligible women were randomly assigned to a control or experimental group. As part of their treatment plan, all participants were referred to one of 14 community-based exercise centers to exercise. Experimental group also exercised at one of two cancer centers each day chemotherapy was administered. Outcome measures include exercise retention and chemotherapy, completion; cancer-related fatigue, nausea/vomiting, peripheral neuropathy, weight gain, and QOL. Outcome measures were assessed prior to every second course of chemotherapy and 3- and 6-months post-chemotherapy. Results: 273 women with Stage I-III breast cancer receiving chemotherapy were enrolled in the study. The number of participants who withdrew from exercise was higher among those in the control group (n= 16; 12.4%) compared with those in the experimental group (n = 10; 6.9%). At cycle 5, those in the experimental group reported less motor peripheral neuropathy than those in the control group (p = .018) and higher physical well-being scores than those in the control group (p = .047). Conclusions: The highest impact of the intervention was on attrition from exercise. Since participants in both the control and experimental groups exercised throughout chemotherapy, it is not surprising that the groups performed comparably with regard to side effects and QOL. Given the positive effects exercise has demonstrated on persons receiving cancer treatment in numerous studies, having patients exercise in the cancer center on the day of chemotherapy is a significant step toward engaging persons receiving chemotherapy in an exercise program.

Giant malignant phyllodes tumor with metastasis to the brain

We present the case of a 32-year-old African American woman with a giant malignant phyllodes tumor that metastasized to the lungs and subsequently the brain. Her treatment included six cycles of adjuvant therapy with AIM (Adriamycin^®, ifosfamide, and mesna) followed by therapy with gemcitabine and docetaxel. A grand mal seizure led to discovery of a 6 × 5 × 5 cm brain mass which was resected. After resection, the patient developed pulmonary edema, repeat seizure activity, and massive intrathoracic progression before succumbing to her disease. This is an unpredictable and understudied neoplasm that can be aggressive and fatal in rare cases.

Scalp Cooling Alopecia Prevention trial (SCALP) for patients with early stage breast cancer

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Background: Adjuvant chemotherapy decreases the risk of recurrence. However, it has distressing side effects, including alopecia. There are no randomized trials assessing modern scalp cooling to prevent alopecia, and success rates in non-randomized trials have varied. Methods: We conducted a multi-center randomized trial to evaluate the safety and efficacy of the Orbis Paxman Hair Loss Prevention System (OPHLPS) in reducing chemotherapy-induced alopecia. Women with stage I-II breast cancer planned to receive anthracycline- or taxane- based chemotherapy for at least four cycles were eligible and randomized in a 2:1 ratio to scalp-cooling or control. Scalp-cooling was done with the OPHLPS 30 minutes prior to, during and 90 minutes after each chemotherapy. The primary efficacy endpoints were hair preservation and device safety. We planned to enroll 235 subjects to provide 85% power to detect a 20% difference in hair preservation. Secondary endpoints included wig/scarf use and quality of life assessed by the EORTC QLQ-30, HADS and BIS. Subjects will be followed for 5 years for recurrence, overall survival, and site of recurrence. One interim analysis was planned to allow the study to stop early for efficacy after 142 subjects were enrolled and evaluable for the primary endpoint. To maintain the overall type 1 error rate, an O’Brien-Fleming spending function was used (interim boundary p = 0.0061). Results: This is the first randomized trial with modern scalp cooling in the world. For the interim analysis, 142 subjects were evaluable. Among them, 48 (50.5%) out of 95 in the cooling group and 0 (0%) out of 47 in the control group had hair preservation. The one-tailed p-value from the Fisher’s exact test is < 0.0001, which crosses the superiority boundary (p = 0.0061). Thus on 9/26/2016 the DSMB stopped the study early. The interim analysis was presented at SABCS 2016. There are 195 subjects enrolled on this clinical trial, and the final subject will be evaluable for the primary outcome February 2017. The final analysis will be presented. Conclusions: Our trial showed that scalp cooling using OPHLPS is highly effective in hair retention. Paxman Coolers has applied for FDA clearance for the OPHLPS based on the results of the interim analysis. Clinical trial information: NCT01986140.

Pathologic complete response after preoperative anti-HER2 therapy correlates with alterations in PTEN, FOXO, phosphorylated Stat5, and autophagy protein signaling

BACKGROUND

To define protein molecular characteristics of tumor cells prior to, and immediately following, preoperative human epidermal growth factor receptor 2 (HER2)-targeted therapy that correlate with pathologic complete response (pCR) or non response (no pCR) to preoperative HER2-directed therapy and chemotherapy.

METHODS

This open-label, phase II study randomized patients with HER2-positive stage II or III invasive breast cancer to trastuzumab, lapatinib, or both, 2 weeks prior to and during chemotherapy with FEC75 for 4 courses; then paclitaxel 80 mg/m2 weekly for 12 courses, then surgery. Core needle biopsies were collected at baseline and after 2 weeks of anti-HER2 therapy prior to chemotherapy. Data were correlated with pCR, defined as absence of invasive tumor in breast and lymph nodes.

RESULTS

Of 100 enrolled patients, the analysis population included those who had surgery and received ≥75% chemotherapy (78% [n=78]). pCRs by arm are: trastuzumab (n=26), 54% [n=14]; lapatinib (n=29), 45% [n=13]; trastuzumab plus lapatinib (n=23), 74% [n=17]). Paired biopsy specimens were available for 49 patients (63%). Tumor cells of patients with pCR in the trastuzumab or lapatinib treatment arms showed nonphosphorylated FOXO, phosphorylated Stat5, and sparse signal-transduction protein network crosstalk representing different patterns of connections with PI3K and autophagy proteins compared with no pCR.

CONCLUSION

In this exploratory study, pCR with preoperative anti-HER2 therapy and chemotherapy correlated with the levels and phosphorylation status of specific baseline signal pathway proteins in tumor cells. These data may provide candidate biomarkers to stratify initial treatment and potential combination therapies for future study. Tissue preservation technology introduced here makes this procedure widely feasible.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00524303.

Abstract P5-20-03: A phase 2, double-blind, randomized, placebo-controlled, dose-finding study of sotatercept for the treatment of patients with chemotherapy-induced anemia and metastatic breast cancer

Background: Sotatercept is a recombinant activin receptor IIA (ActRIIA) ligand trap and is comprised of the extracellular domain of ActRIIA linked to the Fc domain of human IgG1 (ActRIIA-IgG1). Results of preclinical and early clinical studies provide evidence that sotatercept increases the concentration of hemoglobin (Hb) in blood and may constitute a novel treatment for chemotherapy-induced anemia (CIA), a condition that results in significant morbidity.

Methods: This study evaluated the safety of, and hematopoietic response to, sotatercept in patients with CIA and metastatic breast cancer (MBC). Response was defined as increase in Hb ≥1 g/dL for ≥28 consecutive days during treatment or ≤2 months following the last dose, in the absence of red blood cell (RBC) transfusion or treatment with an erythropoiesis stimulating agent (ESA). If RBC transfusion or treatment with an ESA was required, no Hb measurements within 28 days of the RBC transfusion or administration of ESA were used to determine the Hb response. Subjects were randomized to subcutaneous injection of sotatercept (0.1, 0.3, or 0.5 mg/kg) or placebo and were treated on day 1 of each of four 28-day cycles.

Results: Thirty (30) subjects were enrolled and treated (5 placebo, 25 sotatercept). Increases in mean Hb in the 0.3 and 0.5 mg/kg groups were greater than in 0.1 mg/kg and placebo groups. Increases peaked approximately 15 days following treatment and declined over the remaining interval between treatments. Among 23 subjects with confirmed CIA and administered ≥1 dose and followed for ≥57 days (per-protocol analysis), 5/18 (28%) administered sotatercept responded (0/5 [0%] at 0.1 mg/kg; 3/9 [33%] at 0.3 mg/kg; 2/4 [50%] at 0.5 mg/kg) vs 1/5 [20%] administered placebo. Among 13 nonresponders administered sotatercept, 5 (39%) experienced ≥1 dose interruption/reduction, as per protocol, due to elevated Hb. The incidence of adverse events (AEs) was consistent with that reported in patients with MBC. No dose-limiting or dose-related toxicity was observed.

Conclusions: Sotatercept demonstrated dose-dependent hematopoietic activity in subjects with CIA and MBC. The safety findings were generally consistent with the known safety profile of sotatercept. These data suggest that a greater dose of sotatercept or a dose interval &lt;28 days might result in a more sustained, and greater rate of, hematopoietic response.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-03.

Interim safety results of eribulin (E) combined with ramucirumab (RAM) in patients (pts) with advanced metastatic breast cancer (MBC)

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Background: VEGF-mediated angiogenesis contributes to breast cancer (BC) pathogenesis. RAM (IMC-1121B), a fully human IgG1 monoclonal antibody (MAb), targets VEGFR-2, blocking the interaction of VEGF ligands and VEGFR‑2. DC101 (murine anti-VEGFR-2 MAb) impairs vascular function and increases tumor hypoxia in xenograft BC models and inhibits tumor growth in cytotoxic-resistant models. E is a novel non-taxane microtubule inhibitor indicated in MBC pts who have received ≥2 prior chemotherapy regimens, including an anthracycline and a taxane. It is hypothesized that addition of RAM to E as 3rd-5th line therapy in MBC will result in an improvement of median PFS in this ongoing, multicenter, US study. A planned safety analysis of an initial cohort is reported. Methods: Pts with locally recurrent or MBC (HER2+ or HER2-) and 2-4 prior chemotherapy regimens are randomized 1:1 to receive RAM+E or E (E 1.4 mg/m2 Days 1, 8; RAM 10 mg/kg Day 1; q21 days). Pts are stratified by TNBC and prior antiangiogenic therapy status and must have ECOG PS 0-1 and normal LVEF. Planned accrual: 134 pts. Results: Evaluable pts (n=13, 8 RAM+E) received ≥1 dose of RAM+E or E and completed 2 cycles of therapy (or discontinued prior to completing the initial 2 cycles). Median age is 55 yrs. Assessment of adverse events (all cause) revealed nausea, fatigue, headache, and neutropenia were more frequent for RAM+E; anemia was more frequent for E. G1 sensory neuropathy was reported for 1 pt in each arm. One RAM+E pt experienced G3 febrile neutropenia and odynophagia, recovered within a week, and subsequently received reduced dosage (E = 1.1 mg/m2; RAM = 8 mg/kg). No deaths are reported. The safety assessment committee recommended to continue the trial unmodified. Conclusions: Based on preliminary data, the combination of RAM+E demonstrates an acceptable toxicity profile. Accrual continues, with planned updated safety and dose intensity data to be presented at the meeting. [Table: see text]

Final analysis of phase II study of EZN-2208 (PEG-SN38) in metastatic breast cancer (MBC)

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Background: EZN-2208 is a water-soluble PEGylated conjugate of SN38. EZN-2208 results in prolonged exposure of tumors to SN38 via preferential accumulation of EZN-2208 in the tumor and prolonged release of SN38. These data represent the final analysis of our study evaluating EZN-2208 in MBC. Methods: EZN-2208 9 mg/m2 (SN38 equivalents) was delivered as a 60-minute IV infusion, weekly for 3 wks in 4‑wk cycles. The primary objective was to determine the overall response rate (RR) in female patients with metastatic breast cancer (MBC) who had received prior adjuvant or metastatic therapy with either 1) anthracycline and taxane (AT) or 2) anthracycline, taxane, and capecitabine (ATX). Secondary objectives included evaluation of RR based on tumor receptor status, duration of response, progression-free survival (PFS), overall survival (OS), and safety. Results: Patients with MBC (n=164) were treated with a median (range) of 3.3 (0.3-22) cycles of EZN-2208. The objective response rate (RR) was 20% for AT and 9% for ATX. The clinical benefit rate (CBR=%CR + %PR + %SD ≥6 months) was 41% and 27% in patients in the AT and ATX cohorts, respectively. The RR and CBR among ER+ patients were 11% (10/91 pts) and 41.8% (38/91 pts). In patients who progressed during or within 30 days of prior platinum-containing regimens (Platinum Progressors), the CBR was 20% (8/40 pts). Among triple negative breast cancer (TNBC) patients, the RR and CBR were 22.5% (11/49 pts) and 36.7% (18/49 pts). For TNBC, Platinum Progressors, the CBR was 26.1% (6/23 pts). Overall, most common reported drug-related adverse events were diarrhea, nausea and neutropenia. Conclusions: EZN-2208 has notable activity in patients with previously treated MBC and appears to be an active agent for treatment of TNBC. Patients with TNBC, who had been previously treated with a platinum-based regimen, also derive clinical benefit from EZN-2208. The safety profile of EZN-2208 is acceptable with good tolerability in most patients. Further evaluation of EZN-2208 in MBC in general and TNBC in particular is warranted.

P3-16-18: Phase 2, Open-Label Study of EZN-2208 (PEG-SN38) in Patients with Previously Treated Metastatic Breast Cancer

Background

EZN-2208 is a water-soluble PEGylated conjugate of SN38 that results in parenteral delivery, increased solubility, higher exposure, and longer apparent half-life of SN38, as well as more profound deoxyribonucleic acid (DNA) damage and inhibition of angiogenesis. EZN-2208 results in prolonged exposure of tumors to SN38 via preferential accumulation of EZN-2208 in the tumor and prolonged release of SN38 in the blood.

Methods: This trial evaluated EZN-2208 delivered as a 1-h IV infusion weekly for 3 wks in 4-wk cycles. The primary objective was to determine the overall response rate (RR) in female patients with metastatic breast cancer (MBC) who had received prior adjuvant or metastatic therapy with either 1) anthracycline and taxane (AT) or 2) anthracycline, taxane, and capecitabine (Xeloda®) (ATX). Secondary objectives included evaluation of RR based on tumor receptor status, duration of response, progression-free survival (PFS), overall survival (OS), and safety and toxicity. Response was evaluated using RECIST (v1.1).

Results: 148 patients received EZN-2208 in the AT (n=65; median age = 56 y [31-84 y]) or ATX (n=83; median age = 55 y [36-83 y]) cohorts. All 65 patients in the AT cohort had received 0–2 lines of prior cytotoxic therapy for MBC; for the ATX cohort, 31 patients (37%) had received 0–2 prior lines of cytotoxic therapy for MBC, 50 patients (60%) had received 3–4 prior lines, and 2 patients (2%) had received 5 prior lines. Preliminary results follow; final data will be presented at the meeting. Median (range) cycles of EZN-2208 was 2.3 (0.3-14) for AT and 2 (0.3-15) for ATX. Best overall response is shown in the table. RR (PR+uPR) was 22% for AT and 10% for ATX.

Median (95% CI) time to progression was 3.8 mo (3.6−7.4) for AT and 3.3 mo (1.8−3.7) for ATX. Median (95% CI) duration of response was 4.0 mo (3.7−5.6) for AT and 5.2 mo (1.9-..) for ATX. 6-mo PFS (95% CI) was 34% (19%-50%) for AT and 19% (9%-29%) for ATX. Median PFS (95% CI) was 3.8 mo (2.7−5.6) for AT and 2.9 mo (1.83.7) for ATX. Median OS (95% CI) was 9.1 mo (6.1−12.7) for AT and 7.9 mo (6.4−12.9) for ATX. Grade 3 or 4 drug-related adverse events (&gt;10% of patients in either arm) included neutropenia (43%, 33%), diarrhea (11%, 8%), and leukopenia (11%, 6%).