Advancing the Care of Women With HER2-Positive Metastatic Breast Cancer.

HER2 is overexpressed and/or amplified in approximately 20% of breast cancers. It is a clinically aggressive subtype; however, the introduction of targeted therapies has greatly improved survival rates. At JADPRO Live 2022, presenters discussed recent updates to clinical practice for HER2-positive metastatic breast cancer, and how to interpret emerging evidence on HER2-low data. They also highlighted best practices for monitoring and managing side effects for patients on these therapies.

Phase II trial of eribulin in patients who do not achieve pathologic complete response (pCR) following neoadjuvant chemotherapy.

PURPOSE: Women with residual invasive breast cancer at the primary site or axillary lymph nodes following neoadjuvant chemotherapy have a high risk of recurrence. Eribulin improves survival in patients with metastatic breast cancer who progress after anthracycline and taxane therapy. This phase 2 trial assessed the efficacy of postoperative eribulin in breast cancer patients who did not achieve a pCR following standard neoadjuvant chemotherapy. METHODS: Women with localized breast cancer who had residual invasive cancer following ≥ 4 cycles of standard anthracycline and/or taxane-containing neoadjuvant chemotherapy received adjuvant eribulin treatment. HER2-positive patients also received trastuzumab for 1 year. Adjuvant hormonal therapy and locoregional radiotherapy were administered as per institutional guidelines. Primary endpoint was the 2-year DFS rate. Three patient cohorts were analyzed: TNBC (Cohort A), HR+/HER2- (Cohort B), and HER2+ (Cohort C). RESULTS: One hundred twenty-six patients (Cohort A-53, Cohort B-42, and Cohort C-31) were enrolled. Neoadjuvant chemotherapy included a taxane and an anthracycline in 70%. Eribulin was well tolerated; 84% of patients received the planned 6 cycles. After a median follow-up of 28 months, the 24-month DFS rates were 56% (95% CI 42, 69), 83% (95% CI 67, 91), and 73% (95% CI 53, 86) for Cohorts A, B, and C, respectively. The most common grade 3/4 treatment-related adverse events were neutropenia (26%), leukopenia (13%), and neuropathy (7%). CONCLUSION: Administration of adjuvant eribulin after neoadjuvant chemotherapy was feasible and well tolerated. The 24-month DFS rate did not reach the study target levels in any of the cohorts and was similar to DFS previously described in these cohorts following neoadjuvant chemotherapy alone.

TITAN: phase III study of doxorubicin/cyclophosphamide followed by ixabepilone or paclitaxel in early-stage triple-negative breast cancer.

PURPOSE: Ixabepilone is a microtubule stabilizer with activity in taxane-refractory metastatic breast cancer and low susceptibility to taxane-resistance mechanisms including multidrug-resistant phenotypes and high ß-III tubulin expression. Since these resistance mechanisms are common in triple-negative breast cancer (TNBC), ixabepilone may have particular advantages in this patient population. This study evaluated the substitution of ixabepilone for paclitaxel following doxorubicin/cyclophosphamide (AC) in the adjuvant treatment of early-stage TNBC. METHODS: Patients with operable TNBC were eligible following definitive breast surgery. Patients were randomized (1:1) to receive four cycles of AC followed by either four cycles (12 weeks) of ixabepilone or 12 weekly doses of paclitaxel. RESULTS: 614 patients were randomized: 306 to AC/ixabepilone and 308 to AC/paclitaxel. At a median follow-up of 48 months, 59 patients had relapsed (AC/ixabepilone, 29; AC/paclitaxel, 30). The median time from diagnosis to relapse was 20.8 months. The 5-year disease-free survival (DFS) rates of the two groups were similar [HR 0.92; ixabepilone 87.1% (95% CI 82.6-90.5) vs. paclitaxel 84.7% (95% CI 79.7-88.6)]. The estimated 5-year overall survival (OS) rates were also similar [HR 1.1; ixabepilone 89.7% (95% CI 85.5-92.7) vs. paclitaxel 89.6% (95% CI 85.0-92.9)]. Peripheral neuropathy was the most common grade 3/4 event. Dose reductions and treatment discontinuations occurred more frequently during paclitaxel treatment. CONCLUSIONS: Treatment with AC/ixabepilone provided similar DFS and OS in patients with operable TNBC when compared to treatment with AC/paclitaxel. The two regimens had similar toxicity, although treatment discontinuation, dose modifications, and overall peripheral neuropathy were more frequent with AC/paclitaxel. TRIAL REGISTRATION: Clinical Trials.gov Identifier, NCT00789581.

Use of a multiplexed immunoassay (PRO Onc assay) to detect HER2 abnormalities in circulating tumor cells of women with HER2-negative metastatic breast cancer: lack of response to HER2-targeted therapy.

PURPOSE: Determination of HER2 status by testing circulating tumor cells (CTCs), compared to sampling tumor biopsies, may improve patient management by allowing ongoing assessment of HER2 status during the disease course. The PRO Onc assay (Prometheus Laboratories; San Diego, CA) is a multiplexed immunoassay that measures the expression and activation of HER2 in CTCs. In this study, we screened patients with metastatic HER2-negative breast cancer with the PRO Onc assay; patients with HER2 overexpression or activation received a trial of HER2-targeted therapy. METHODS: In Part 1 of the trial, patients with HER2-negative breast cancer were screened with the PRO Onc assay to confirm the presence of a cohort that tested HER2-positive. After this finding was confirmed, patients in Part 2 of the study with HER2 abnormalities received a trial of treatment with trastuzumab/pertuzumab. RESULTS: In Part 1, 31 of 57 specimens contained CTCs; of these, 12 (38 %) showed HER2 abnormalities by PRO Onc assay. In Part 2, 129 of 226 patients (57 %) had CTCs; 24 of these patients (19 %) had HER2 abnormalities detected. Fourteen patients were treated with HER2-targeted therapy. Twelve of 14 patients progressed within 6 weeks, one patient had a brief (12 weeks) partial response, and one patient was stable for 12 weeks. CONCLUSIONS: HER2 overexpression or activation was detected by the PRO Onc assay in 22 % of HER2-negative patients with CTCs. However, HER2-targeted therapy was not effective in such patients. FISH and IHC staining remain the standards for HER2 determination.

Ramucirumab With Eribulin Versus Eribulin in Locally Recurrent or Metastatic Breast Cancer Previously Treated With Anthracycline and Taxane Therapy: A Multicenter, Randomized, Phase II Study.

BACKGROUND: Use of antiangiogenic agents in treatment of metastatic breast cancer (MBC) remains controversial. We evaluated the efficacy and safety of ramucirumab and eribulin versus eribulin alone as third- to fifth-line therapy in women with advanced breast cancer. PATIENTS AND METHODS: In this randomized (1:1), open-label, phase II study, US women aged 18 years or older with 2 to 4 previous chemotherapy regimens for locally recurrent or MBC, previous anthracycline and taxane treatment, and Eastern Cooperative Oncology Group performance status of 0 or 1 received ramucirumab with eribulin or eribulin alone in 21-day cycles (eribulin 1.4 mg/m2 intravenously on days 1 and 8; ramucirumab 10 mg/kg intravenously on day 1). Randomization was stratified according to previous antiangiogenic therapy and triple-negative status. The primary end point was progression-free survival (PFS) in the intention to treat population. RESULTS: One hundred forty-one women were randomized to ramucirumab with eribulin (n = 71) or eribulin alone (n = 70). Median PFS for ramucirumab with eribulin was 4.4 months (95% confidence interval [CI], 3.1-6.7) compared with 4.1 months (95% CI, 3.2-5.6) for eribulin (hazard ratio [HR], 0.83; 95% CI, 0.56-1.23; P = .35). Median overall survival in patients who received ramucirumab with eribulin was 13.5 months (95% CI, 10.4-17.9) compared with 11.5 months (95% CI, 9.0-17.3) in patients who received eribulin alone (HR, 0.91; 95% CI, 0.59-1.41; P = .68); objective response rate was 21% (13 of 62 patients) for the combination and 28% (17 of 60 patients) for eribulin alone. No unexpected toxicity was identified for the combination. CONCLUSION: Ramucirumab combined with eribulin did not significantly improve PFS in advanced MBC.

Panitumumab, Gemcitabine, and Carboplatin as Treatment for Women With Metastatic Triple-Negative Breast Cancer: A Sarah Cannon Research Institute Phase II Trial.

BACKGROUND: Triple-negative breast cancer (TNBC) is a subtype with poor prognosis, and treatment options are limited to chemotherapy. Because the epidermal growth factor receptor (EGFR) is overexpressed in up to 70% of these tumors, this phase II trial was designed to evaluate the efficacy and safety of panitumumab in combination with gemcitabine and carboplatin as first- or second-line treatment for metastatic TNBC. PATIENTS AND METHODS: Adult women with metastatic TNBC with a maximum of 1 previous chemotherapy regimen were eligible. Patients received gemcitabine intravenous (I.V.) 1500 mg/m2, carboplatin area under the concentration-time curve = 2.5 I.V., and panitumumab 6 mg/kg I.V. every 2 weeks. Treatment continued until disease progression or unacceptable toxicity, with disease evaluations every 6 weeks. The primary end point was progression-free survival (PFS). Archival tissue was collected for correlative analysis, to include phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha, p53, phosphatase and tensin homolog, EGFR, and status. RESULTS: Between May 2010 and August 2012, 71 women (median age, 54 years; 14% de novo stage IV) were treated. At a median follow-up of 11 months, the median PFS was 4.4 months (95% confidence interval, 3.2-5.5 months). The objective response rate was 42% (complete response, 1; partial response, 29). Treatment-related toxicity included: rash, 50 patients (70%), fatigue, 37 patients (52%), neutropenia, 32 patients (45%; 2 episodes of febrile neutropenia), and thrombocytopenia, 32 patients (45%). CONCLUSION: Although the addition of panitumumab was feasible, the results of this trial do not support combination of panitumumab with gemcitabine and carboplatin in the treatment of patients with TNBC.

Neoadjuvant Ixabepilone/Carboplatin/Trastuzumab in HER2-Positive Operable Breast Cancer: A Phase II Trial of the Sarah Cannon Research Institute.

BACKGROUND: Ixabepilone is a member of the epothilone class of antineoplastic agents with activity against taxane-resistant tumors, and low susceptibility to common mechanisms of tumor resistance. This study evaluated ixabepilone in lieu of a taxane in combination with carboplatin and trastuzumab as neoadjuvant treatment for operable HER2-positive breast cancer. PATIENTS AND METHODS: Patients ≥ 18 years of age with histologically-confirmed HER2-positive adenocarcinoma of the breast (clinical T1-T3, N0-N2, M0), normal left ventricular ejection fraction, and adequate organ function received trastuzumab 6 mg/kg intravenous (I.V.) (with 8 mg/kg loading dose cycle 1), ixabepilone 40 mg/m(2) I.V., and carboplatin area under the curve = 6.0 I.V. on day 1 of each 21-day cycle. Prophylactic growth factor support was permitted. After completing 6 cycles, patients underwent definitive surgery. After surgery, patients continued trastuzumab every 3 weeks for a total of 1 year. Locoregional radiation therapy and endocrine therapy was administered per institutional guidelines. The primary end point was the rate of pCR. RESULTS: Fifty-eight eligible women (median tumor size, 3.0 cm; clinical axillary lymph node involvement, 67%) initiated treatment between April 2009 and February 2010. Fifty-two patients (90%) underwent surgery, and pCR was observed in 27 patients (52%). Grade 3/4 neutropenia was the most common toxicity, occurring in 69% of patients and complicated by fever in 4 patients. CONCLUSION: The combination of ixabepilone, carboplatin, and trastuzumab was feasible and active as a neoadjuvant regimen. Although the pCR rate of 52% falls within the range reported with other taxane/trastuzumab-based regimens, the greater incidence of severe neutropenia is a disadvantage for this regimen.

Addition of bevacizumab to three docetaxel regimens as adjuvant therapy for early stage breast cancer.

Docetaxel-containing chemotherapy improves disease-free survival (DFS) and overall survival in patients with early stage breast cancer. Bevacizumab improves response rate and DFS in metastatic breast cancer. However, adding antivascular endothelial growth factor therapy to anthracycline-containing chemotherapy may increase cardiotoxicity. This trial evaluates the feasibility of adding bevacizumab to three standard adjuvant docetaxel regimens with a primary endpoint of grade ≥3 congestive heart failure (CHF). Phase IIb, randomized, non-comparative study of women with previously untreated node-positive or high-risk node-negative breast cancer. Human epidermal growth factor receptor 2 (HER2)-negative patients were randomized to: (arm A) doxorubicin + cyclophosphamide followed by docetaxel or (arm B) docetaxel + doxorubicin + cyclophosphamide. HER2-positive patients (arm C) received docetaxel + carboplatin + trastuzumab for 52 weeks. All patients received bevacizumab beginning on day 1 for 52 weeks. Safety data in 212 women (mean age = 53.1 years) show that 1 patient each in arm A (1.3 %) and arm C (1.7 %), and 3 patients in arm B (4.0 %) experienced clinical CHF grade ≥3. A decreased ejection fraction was observed in 1 patient each in arms A and C, and cardiac disorder was observed in 12.8, 22.7, and 8.5 % in arms A, B, and C, respectively. A grade 3/4 treatment-emergent adverse event was reported in 82.1, 84.0, and 52.5 % of participants in arms A, B, and C, respectively. Kaplan-Meier estimates of DFS show rates at 24 months of 85.5, 90.4, and 90.4 % in arms A, B, and C, respectively. Adding bevacizumab to three standard docetaxel-based chemotherapy regimens as adjuvant treatment in patients with node-positive and high-risk node-negative breast cancer resulted in a low rate of clinical CHF grade ≥3. Maintenance bevacizumab monotherapy did not identify any new safety signals. Breast cancer recurrence/relapse, secondary malignancies, and death were uncommon, although the follow-up time in this study was relatively short.

A phase II trial of dose-dense neoadjuvant gemcitabine, epirubicin, and albumin-bound paclitaxel with pegfilgrastim in the treatment of patients with locally advanced breast cancer.

BACKGROUND: Neoadjuvant anthracycline/taxane combinations, with or without gemcitabine, produce pathologic complete responses (pCRs) in 15%-25% of patients. In this multicenter phase II study, we attempted to increase efficacy and decrease toxicity of a 3-drug gemcitabine-containing neoadjuvant regimen by administering dose-dense therapy with pegfilgrastim, and including albumin-bound paclitaxel as the taxane. PATIENTS AND METHODS: A total of 123 patients with locally advanced breast cancer were enrolled. Patients were treated with 6 doses of neoadjuvant gemcitabine 2000 mg/m2, epirubicin 50 mg/m2, and albumin-bound paclitaxel 175 mg/m2 intravenously administered at 14-day intervals. Following neoadjuvant chemotherapy, patients underwent either mastectomy or breast conservation surgery; pathologic response to treatment was assessed. Postoperatively, patients received 4 doses of gemcitabine 2000 mg/m2 with albumin-bound paclitaxel 220 mg/m2 at 14-day intervals. Pegfilgrastim 6 mg was administered subcutaneously on day 2 following each dose of chemotherapy. RESULTS: A total of 116 patients (95%) completed neoadjuvant chemotherapy and had subsequent surgical resection. Twenty-three patients (20%) had a pCR. The estimated 3-year progression-free survival (PFS) and overall survival rates were 48% and 86%, respectively. Neoadjuvant treatment was well tolerated; only 11% of the patients had grade 3/4 neutropenia, with 1 episode of neutropenic fever. Other grade 3/4 toxicities occurred in < 10% of the patients. CONCLUSION: Neoadjuvant biweekly chemotherapy with gemcitabine/epirubicin/albumin-bound paclitaxel with pegfilgrastim is feasible and well tolerated. The pCR rate of 20% and the 3-year PFS rate of 48% are similar to results achieved with other commonly used neoadjuvant regimens.

Retinoic acid receptor-beta2 promoter methylation in random periareolar fine needle aspiration.

Methylation of the retinoic acid receptor-beta2 (RARbeta2) P2 promoter is hypothesized to be an important mechanism for loss of RARbeta2 function during early mammary carcinogenesis. The frequency of RARbeta2 P2 methylation was tested in (a) 16 early stage breast cancers and (b) 67 random periareolar fine needle aspiration (RPFNA) samples obtained from 38 asymptomatic women who were at increased risk for breast cancer. Risk was defined as either (a) 5-year Gail risk calculation > or = 1.7%; (b) prior biopsy exhibiting atypical hyperplasia, lobular carcinoma in situ, or ductal carcinoma in situ; or (c) known BRCA1/2 mutation carrier. RARbeta2 P2 promoter methylation was assessed at two regions, M3 (-51 to 162 bp) and M4 (104-251 bp). In early stage cancers, M4 methylation was observed in 11 of 16 (69%) cases; in RPFNA samples, methylation was present at M3 and M4 in 28 of 56 (50%) and 19 of 56 (38%) cases, respectively. RPFNAs were stratified for cytologic atypia using the Masood cytology index. The distribution of RARbeta2 P2 promoter methylation was reported as a function of increased cytologic abnormality. Methylation at both M3 and M4 was observed in (a) 0 of 10 (0%) of RPFNAs with Masood scores of < or = 10 (nonproliferative), (b) 3 of 20 (15%) with Masood scores of 11 to 12 (low-grade proliferative), (c) 3 of 10 (30%) with Masood scores of 13 (high-grade proliferative), and (d) 7 of 14 (50%) with Masood scores of 14 of 15 (atypia). Results from this study indicate that the RARbeta2 P2 promoter is frequently methylated (69%) in primary breast cancers and shows a positive association with increasing cytologic abnormality in RPFNA.