scholarly journals Single-cell profiling guided combinatorial immunotherapy for fast-evolving CDK4/6 inhibitor resistant HER2-positive breast cancer

2019 ◽  
Author(s):  
Qingfei Wang ◽  
Ian H. Guldner ◽  
Samantha M. Golomb ◽  
Longhua Sun ◽  
Jack Harris ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Single Cell ◽  
Kinase Inhibitor ◽  
Acquired Resistance ◽  
Tumor Evolution ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Therapy Regimen ◽  
Her2 Breast Cancer ◽  
Combinatorial Immunotherapy

AbstractDevelopment of acquired resistance to targeted cancer therapy is one of the most significant clinical challenges. Acquiring resistance under drug selection pressure is a result of evolutionary adaptation to a complex and dynamic tumor microenvironment (TME). New therapy regimens combining CDK4/6 inhibitor are under active investigation in clinical trials to treat HER2+ breast cancer patients. In parallel with clinical trial settings, in this study, we sought to prospectively model the tumor evolution in response to a targeted therapy regimen in vivo and identify a clinically actionable strategy to combat potential acquired resistance. Notably, despite a promising initial response, acquired resistance emerged rapidly to the anti-Her2/Neu antibody plus CDK4/6 inhibitor Palbociclib combination treatment. By leveraging high-throughput single-cell analyses of the evolving tumors over the course of treatments, we revealed a distinct immunosuppressive immature myeloid cell (IMC) population infiltrated in the resistant TME. Guided by single-cell transcriptome analysis, we demonstrated a combinatorial immunotherapy of IMC-targeting tyrosine kinase inhibitor cabozantinib and immune checkpoint blockades enhanced anti-tumor immunity, and overcame the resistance. Further, sequential combinatorial immunotherapy enabled a sustained control of the rapidly evolving CDK4/6 inhibitor-resistant tumors. Our study demonstrates a translational framework for treating rapidly evolving tumors through preclinical modeling and single-cell analyses. Our findings provide a rationale for an immediate clinical proposition of combinatorial immunotherapy for HER2+ breast cancer as a strategy to mitigate the emergence of resistance.

Pharmacokinetic (PK) analyses in CSF and plasma from TBCRC049, an ongoing trial to assess the safety and efficacy of the combination of tucatinib, trastuzumab and capecitabine for the treatment of leptomeningeal metastasis (LM) in HER2 positive breast cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1044-1044
Author(s):  
Erica Michelle Stringer-Reasor ◽  
Barbara Jane O'Brien ◽  
Ariel Topletz-Erickson ◽  
Jason B White ◽  
Mina Lobbous ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Kinase Inhibitor ◽  
Plasma Concentrations ◽  
Clinical Signs ◽  
Leptomeningeal Metastasis ◽  
Newly Diagnosed ◽  
Her2 Positive ◽  
Safety And Efficacy ◽  
Her2 Breast Cancer ◽  
Metastatic Setting

1044 Background: Tucatinib is a potent and highly selective HER2-targeted tyrosine kinase inhibitor approved for use in combination with trastuzumab and capecitabine for patients with metastatic HER2+ breast cancer (MBC) who have received ≥1 prior HER2-based regimen in the metastatic setting, including patients with brain metastases (BM). TBCRC049 (NCT03501979) is an investigator-initiated phase 2 single-arm study currently enrolling to evaluate the safety and efficacy of tucatinib, trastuzumab and capecitabine in HER2+ BC with newly diagnosed LM. Here, we report the pre-specified pharmacokinetic (PK) analysis for the first 15 patients to determine bioavailability of tucatinib and its predominant metabolite, ONT-993, in the CSF. Methods: Eligible patients included adults with HER2+ MBC, KPS > 50, and newly diagnosed, untreated LM (defined as positive CSF cytology and/or radiographic evidence of LM, plus clinical signs/symptoms). Patients with treated or concurrent/new BM were allowed. The primary endpoint is overall survival with an accrual goal of 30 pts. Parallel PK samples were collected in plasma and CSF via Ommaya reservoir on day 1 of cycles 1 and 2 at 0h (baseline), 2-3h, 5-7h and 24h (optional) following initiation of tucatinib 300 mg BID. Tucatinib and ONT-993 were quantified in plasma (n=15) and CSF (n=13) using validated liquid chromatography-mass spectrometry methods. Results: Tucatinib and ONT-993 plasma concentrations were consistent with previous studies and exhibited high interindividual variability. Tucatinib and ONT-993 were detectable in the CSF within 2 hours post tucatinib administration; concentrations ranged from 0.57 to 25 ng/mL for tucatinib (IC50 for tucatinib against HER2 is 3.3 ng/mL) and 0.28 to 4.7 ng/mL for ONT-993. Tucatinib concentrations in the CSF per timepoint were in a similar range to unbound plasma (plasmaub) tucatinib. CSF to plasmaub ratios were generally consistent over time; the steady-state (cycle 2) median tucatinib CSF to plasmaub ratio was 0.83 (0.19 to 2.1). ONT-993 CSF to plasmaub ratios were similar to tucatinib CSF to plasmaub ratios. Conclusions: In patients with LM from HER2+MBC who were treated with tucatinib, trastuzumab, and capecitabine, tucatinib and ONT-993 were detectable in the CSF of all patients at median levels similar to plasmaub tucatinib. This is the first documented evidence of tucatinib distributing into the CSF in patients with HER2+MBC. Efficacy and safety of tucatinib, trastuzumab, and capecitabine in patients with HER2+ LM will be reported upon completion of TBCRC 049 accrual. Clinical trial information: NCT03501979 .

Neratinib in HER2-Positive Breast Cancer Patients

2019 ◽  
Vol 53 (6) ◽  
pp. 612-620 ◽  
Author(s):  
Rutugandha Paranjpe ◽  
Dima Basatneh ◽  
Gabriel Tao ◽  
Carmine De Angelis ◽  
Sobia Noormohammed ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Disease Free Survival ◽  
Common Adverse Effect ◽  
Stage I ◽  
Phase Iii ◽  
Therapeutic Window ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Safety And Efficacy ◽  
Her2 Breast Cancer

Objective:To review the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of neratinib in human epidermal growth factor receptor (HER2)+ breast cancer (BC). Data Sources: A PubMed search was performed using the term neratinib between September 12, 2018, and November 21, 2018. References of published articles and reviews were also assessed for additional information. Study Selection and Data Extraction: English-language preclinical and clinical studies on the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of neratinib were evaluated. Data Synthesis: Neratinib, an irreversible inhibitor of HER1, HER2, and HER4, is Food and Drug Administration approved for the extended adjuvant treatment of stage I-III HER2+ BC to follow trastuzumab-based therapy. A phase III study has demonstrated statistically significant improvement in 5-year disease-free survival rate (90.2 vs 87.7; hazard ratio = 0.73, 95% CI = 0.57-0.92, P = 0.0083). Its most common adverse effect is diarrhea, observed in more than 90% of patients. The incidence of grade 3/4 diarrhea (~40%) is reduced by half with loperamide prophylaxis, which is recommended for the first 8 weeks of neratinib therapy. Other common adverse reactions are nausea and fatigue. The patients need to be monitored for liver function tests and drug interactions with acid-reducing agents, CYP3A4 inhibitors/inducers, and P-glycoprotein substrates with narrow therapeutic window. Relevance to Patient Care and Clinical Practice: American Society of Clinical Oncology and National Comprehensive Cancer Network clinical guidelines suggest the use of neratinib for extended adjuvant therapy following 1-year trastuzumab in stage I to III HER2+ BC. Diarrhea remains a clinically significant but manageable adverse event. Conclusion: Neratinib significantly improves treatment outcomes and has manageable toxicity in stage I to III HER2+ BC patients.

Correlation of quantitative p95HER2, HER2, and HER3 protein expression with pathologic complete response (pCR) in HER2-positive breast cancer patients (pts) treated with neoadjuvant chemotherapy and trastuzumab.

2012 ◽  
Vol 30 (27_suppl) ◽  
pp. 137-137 ◽  
Author(s):  
Jose Caetano Villasboas ◽  
Judith Hurley ◽  
Jodi Marie Weidler ◽  
Agnes Paquet ◽  
Carmen Gomez Fernandez ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Pathologic Complete Response ◽  
Metastatic Breast ◽  
Complete Response ◽  
Invasive Disease ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Additional Information ◽  
Her2 Breast Cancer ◽  
Poor Outcomes

137 Background: Elevated p95HER2 [HER2-M611-CTF (carboxy-terminal-fragment) also known as p95] expression has been correlated with poor outcomes in HER2+ pts with metastatic breast cancer treated with trastuzumab (T); however, limited data is available on the correlation between p95 and pCR to T in the neoadjuvant (NEO) setting, where p95 was measured by immunohistochemistry. The current study aims to determine whether quantitative p95, HER3 and HER2 expression correlated with pCR in pts treated with T + chemotherapy in the NEO setting. Methods: pCR data and quantitative HER2 (H2T), p95, and HER3 (H3T) results by HERmark/VeraTag assays were available in 45 patient cases with pre-therapy, formalin-fixed, paraffin-embedded breast tumors. pCR was defined as the absence of invasive disease in the breast. Quantitative biomarker data were correlated with pCR according to previously published or presented biomarker cutoffs. Results: The overall pCR rate was 46.7% (ER+: 14.3% vs. ER-: 75%; p<0.0001) and was significantly associated with higher H2T levels (p=0.02) and lower H3T levels (p=0.04). In ER- subjects (N=24), no difference in H2T levels was observed between pCR vs non-pCR groups (median H2T=111.5 vs 150.5, respectively; p=0.721). However, within the ER+ group (N=21), H2T levels were significantly higher in the pCR group vs non-pCR group (median H2T=254 vs 37.3; p=0.024). Using multivariate logistic regression, increasing log(H2T) (p = 0.012), ER-negativity (p = 0.027) and low p95 (p = 0.074) were found to correlate or trend with pCR. Conclusions: pCR was significantly associated with high H2T, particularly in ER+ HER2+ breast cancer pts who received NEO therapy with T + chemotherapy. Lower H3T was also associated with pCR. A trend towards pCR was seen in tumors with low p95. These data suggest that quantitative H2T, H3T and p95 may provide additional information on response to T-based regimens in breast cancer stratified by ER status. Additional investigation into the relationship between quantitative H2T, p95 and H3T expression and T response in the NEO setting in larger cohorts is warranted.

Rate of use of NCCN “preferred” chemotherapy regimens for the treatment of HER2 positive breast cancer.

2017 ◽  
Vol 35 (8_suppl) ◽  
pp. 163-163
Author(s):  
Eric J. Gratias ◽  
Margaret Rausa ◽  
Lee N. Newcomer ◽  
Kurt Andrews ◽  
Nick Andrews ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Adjuvant Chemotherapy ◽  
Neoadjuvant Chemotherapy ◽  
Cancer Patients ◽  
Treatment Options ◽  
Management Program ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Nccn Guidelines ◽  
Her2 Breast Cancer

163 Background: The National Comprehensive Cancer Network (NCCN) Guidelines represent a well-established standard of care for the treatment of HER2+ breast cancer patients. eviCore healthcare is a licensee of NCCN that uses the NCCN guidelines to support its proprietary chemotherapy management program. All regimens assigned NCCN Category of Evidence 1, 2A, or 2B are adherent treatments in the eviCore program. NCCN recommends many systemic treatment options for HER2+ breast cancer, and a limited group is designated by NCCN as “preferred” based on superior efficacy and/or safety. This study evaluated the frequency of NCCN-preferred regimen use by practicing oncologists in HER2+ breast cancer patients. Methods: Chemotherapy authorizations for all HER2+ breast cancer patients with ≥ 1 injectable drug from 4/1/2015-9/30/2016 for multiple payers were included; > 90% of authorizations occurred in United HealthCare members. Cases with incomplete data were excluded. 3685 fully evaluable cases were stratified by stage, ER/PR status, and NCCN-preferred vs. NCCN-recommended status. The frequency of NCCN-preferred regimen selection was calculated for each subgroup. Results: There were 2883 HER2+/ER+ and/or PR+ cases and 802 HER2+/ER-/PR- cases. The highest frequency of NCCN-preferred regimen use occurred in neoadjuvant chemotherapy for patients with Stage III HER2+/ER+ and/or PR+ disease, where 88% of 289 patients used an NCCN-preferred regimen. Metastatic HER2+ patients had a markedly lower rate of NCCN-preferred regimen use at 62% of 557 cases. Only 48% of 1096 patients with Stage I/II HER2+/ER+ and/or PR+ disease received NCCN-preferred regimens. Conclusions: Patients receiving neoadjuvant chemotherapy for HER2+ breast cancer receive NCCN-preferred regimens at significantly higher rates than patients receiving adjuvant chemotherapy or metastatic treatment. Less than half of patients receiving adjuvant chemotherapy are receiving NCCN-preferred regimens. Further study is needed to determine the reasons for low preferred regimen use and ways to optimize preferred regimen use in HER2+ breast cancer.

Phase II study of preoperative chemotherapy versus standard postoperative chemotherapy in HR-negative HER2-positive breast cancer patients.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e12118-e12118
Author(s):  
Meng Xiu ◽  
Pin Zhang
Keyword(s):  
Breast Cancer ◽  
Preoperative Chemotherapy ◽  
Postoperative Chemotherapy ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Her2 Breast Cancer ◽  
Kaplan Meier ◽  
Significant Difference ◽  
Risk Patients

e12118 Background: HR-/HER2+ breast cancer is a subtype with aggressive characteristic and poor survival. More clinical evidence are needed for choice of therapeutic strategies. Methods: Patients with T1-3N0-3M0 received preoperative chemotherapy (PTX 175 mg/m2, CBP AUC 4, q2w*6) combined with trastuzumab (2mg/kg qw) or standard postoperative chemotherapy such as ddAC-PH, AC-PH, TCH. The primary endpoint was RFS. Results: 86 patients were enrolled, 43 received preoperative chemotherapy (pre arm) and the other 43 received postoperative chemotherapy (post arm). There was no significant difference in baseline between the two arms. 22.1% of patients were stage IIA, 25.6% IIB, 34.9% IIIA, and 18.6% IIIC. At a median follow-up of 33.4 months, 16 patients had relapsed (pre arm 8, post arm 8). The median time from diagnosis to relapse was 22.8 months (7.1-49.2) and 23.8 months (11.4-37.4) in pre and post arm. Kaplan-Meier survival analysis estimated that the 3-year RFS were similar (pre vs post: 73.4% vs 75.4%, p= 0.631). Only 1 death occurred in post arm. Table showed that in subgroups, there was no statistical difference in risk of recurrence between pre and post arms. In pre arm, ORR was 97.7% clinically, and pCR (ypT0/TisN0) was 39.0%. No patients achieved pCR relapsed, and the residual invasive lesions indicated poor prognosis. Table showed that Neo-Bioscore 4-5 was related to recurrence event significantly ( p= 0.021). The rate of breast-conserving in pre arm was higher (19.5% vs 9.3%), and PCb regiments every 2 weeks had similar adverse effects with standard chemotherapy, and less patients had dose reductions (18.6% vs 25.6%). Conclusions: Preoperative chemotherapy versus standard postoperative chemotherapy results in similar RFS among HR-/HER2+ patients. Preoperative chemotherapy can identify prognosis of patients early by Neo-Bioscore and adjuvant therapy should be strengthened for high-risk patients. PCb every 2 weeks combined with trastuzumab can be an option of preoperative therapy for HER2+ breast cancer. Clinical trial information: NCT02934828. [Table: see text]

scholarly journals Pyrotinib in the treatment of women with advanced HER2 positive breast cancer: A multicenter, prospective, real-world study.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e13012-e13012
Author(s):  
Jifeng Feng ◽  
Lili Zhang ◽  
Xiaohong Wu ◽  
Jun Zhou ◽  
Mingzhen Zhu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Real World ◽  
Kinase Inhibitor ◽  
Objective Response ◽  
Progression Free Survival ◽  
Efficacy Evaluation ◽  
Her2 Positive ◽  
Her2 Positive Breast Cancer ◽  
Her2 Breast Cancer ◽  
Positive Breast Cancer

e13012 Background: Pyrotinib is a newly-developed irreversible pan-ErbB receptor tyrosine kinase inhibitor. The efficacy of pyrotinib in patients with different baseline characteristics in the actual clinical practice has been rarely reported. This study analyzed the efficacy and safety of pyrotinib in the real world. Methods: Patients with histologically confirmed advanced HER2 positive breast cancer were included in the analyses. All patients received pyrotinib-based therapy were given pyrotinib once a day in a 21-day cycle. The primary endpoint was progression-free survival (PFS). Secondary endpoints included adverse events (AE), objective response rate (ORR), disease control rate (DCR), and overall survival (OS). Results: A total of 132 patients (median age: 52 years [29-78]) were enrolled from February 2019 to March 2020. 94(71.21%) patients had visceral metastatic lesions and 20 (15.15%) had brain metastases. HR+, HR-, or unknown HR status for primary tumor accounted for 56.82%, 42.42%, 0.76%, respectively. 115(87.12%) patients were previously administered with trastuzumab. 96(72.73%) patients received pyrotinib-based therapy as a second or further line of treatment. 94(71.21%) patients initiated pyrotinib treatment at 400 mg. Treatment regimens were pyrotinib plus capecitabine (55.30%), pyrotinib combined with trastuzumab (18.18%), and pyrotinib monotherapy (8.33%), pyrotinib combined with endocrine therapy, radiotherapy or antiangiogenic drugs (3.79%). A total of 132 patients were included in PFS analysis. mPFS was 12.0 months (95%CI 8.1-18.8). mPFS for patients without primary trastuzumab-resistant breast cancer was 14.1 months (95%CI 8.7-23.3). Patients receiving pyrotinib-based therapy as their ≥3 lines treatment had lower mPFS than those receiving pyrotinib-based therapy as their < 3 lines treatment (8.8 vs. 15.1 months, P= 0.119). mPFS in patients receiving regimen with and without capecitabine were 15.1 months and 8.4 months, respectively ( P= 0.081). As of data cutoff, mOS has not yet been reached. Among the 65 patients available for efficacy evaluation, 1 (1.54%) patient achieved complete response (CR), 24 (36.92%) patients had partial response (PR), 30 (46.15%) patients achieved stable disease (SD), and 10 (15.38%) patients had progression disease (PD), resulting in an ORR of 38.46% and DCR of 84.62%. The most common AE was diarrhea (84.17%), but only 5 (4.17%) patients were reported grade ≥ 3 diarrhea which could be well controlled. Other AEs with an incidence higher than 20.00% were anemia (36.67%), leukopenia (25.83%), vomiting (25.00%), neutropenia (22.50%). No treatment-related death occurred. Conclusions: Pyrotinib demonstrated an encouraging efficacy and manageable safety in patients with advanced HER2+ breast cancer. More data would be analyzed and reported in the future. Clinical trial information: ChiCTR1900021819.

scholarly journals Modelling hypersensitivity to trastuzumab defines biomarkers of response in HER2 positive breast cancer

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Laura Díaz-Gil ◽  
Fara Brasó-Maristany ◽  
Claudriana Locatelli ◽  
Ariana Centa ◽  
Balász Győrffy ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Surface ◽  
Therapeutic Option ◽  
Cell Counting ◽  
Her2 Overexpression ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Cellular Models ◽  
Her2 Breast Cancer

Abstract Background Trastuzumab-based therapies are the therapeutic option for HER2 positive (HER2+) breast cancer. HER2 amplification is the only biomarker validated for trastuzumab-based therapies. However, a proportion of tumors become refractory during treatment course. For this reason, the finding of new biomarkers beyond HER2 overexpression to identify patients who would benefit most from trastuzumab regimens is of outstanding importance. Methods Models of trastuzumab-resistant or hypersensitive cells were generated by exposure to trastuzumab. Cell surface, total HER2, and analyses of proteins involved in cell cycle or apoptosis were analyzed by western blotting. Cell proliferation was analyzed by cell counting, cell cycle and apoptosis was evaluated by FACS. Transcriptomic characterization of the cellular models was performed using bioinformatic online tools, and clinico-genomic analyses were performed using the PAMELA clinical trial data. Results Besides differing in sensitivities to trastuzumab, the different cellular models also showed distinct response to other anti-HER2 drugs (lapatinib, neratinib, pertuzumab and T-DM1) used in the clinic. That differential effect was not due to changes in cell surface, total or activated HER2. Trastuzumab caused important induction of cell death in hypersensitive cells but not in parental or resistant cells. Transcriptomic analyses of these cellular models together with querying of online databases allowed the identification of individual genes and gene signatures that predicted prognosis and trastuzumab response in HER2+ breast cancer patients. Conclusion The identification of trastuzumab response biomarkers may be used to select patients particularly sensitive to facilitate the use of trastuzumab-based therapies and refine follow-up guidelines in patients with HER2+ tumors.

scholarly journals Prognostic factors of brain metastasis and survival among HER2-positive metastatic breast cancer patients: a systematic literature review

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Michelle D. Hackshaw ◽  
Heather E. Danysh ◽  
Mackenzie Henderson ◽  
Eric Wang ◽  
Nora Tu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Prognostic Factors ◽  
Brain Metastasis ◽  
Literature Review ◽  
Growth Factor Receptor ◽  
Metastatic Breast ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Two Phase ◽  
Her2 Breast Cancer

Abstract Background Patients with breast cancer who overexpress the human epidermal growth factor receptor 2 (HER2) and subsequently develop brain metastasis (BM) typically experience poor quality of life and low survival. We conducted a comprehensive literature review to identify prognostic factors for BM and predictors of survival after developing BM, and the effects of therapies with different mechanisms of action among patients with HER2+ breast cancer (BC). Methods A prespecified search strategy was used to identify research studies investigating BM in patients with HER2+ BC published in English during January 1, 2009–to June 25, 2021. Articles were screened using a two-phase process, and data from selected articles were extracted. Results We identified 25 published articles including 4097 patients with HER2+ BC and BM. Prognostic factors associated with shorter time to BM diagnosis after initial BC diagnosis included younger age, hormone receptor negative status, larger tumor size or higher tumor grade, and lack of treatment with anti-HER2 therapy. Factors predictive of longer survival after BM included having fewer brain lesions (< 3 or a single lesion) and receipt of any treatment after BM, including radiosurgery, neurosurgery and/or systemic therapy. Patients receiving combination trastuzumab and lapatinib therapy or trastuzumab and pertuzumab therapy had the longest median survival compared with other therapies assessed in this review. Conclusions More research is needed to better understand risk factors for BM and survival after BM in the context of HER2+ BC, as well as the assessment of new anti-HER2 therapy regimens that may provide additional therapeutic options for BM in these patients.

scholarly journals Randomized phase-II evaluation of letrozole plus dasatinib in hormone receptor positive metastatic breast cancer patients

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Devchand Paul ◽  
Svetislava J. Vukelja ◽  
Frankie Ann Holmes ◽  
Joanne L. Blum ◽  
Kristi J. McIntyre ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Phase Ii ◽  
Kinase Inhibitor ◽  
Acquired Resistance ◽  
Metastatic Breast ◽  
Progression Free Survival ◽  
Therapy Resistance ◽  
Breast Cancer Patients ◽  
Er Positive

Abstract The non-receptor tyrosine kinase Src activation plays a role in the malignant progression of breast cancer, including development of endocrine therapy resistance and survival of bone metastases. This study investigated whether adding Src kinase inhibitor dasatinib to aromatase inhibitor (AI) therapy improved outcomes in estrogen receptor (ER)-positive, HER2-negative metastatic breast cancer (MBC). Postmenopausal patients with ER-positive, HER2-negative MBC (0–1 prior chemotherapies and no prior AI for MBC) were eligible for this non-comparative, parallel group, phase-II study. Patients were randomized to letrozole (2.5 mg/day PO) alone or with dasatinib (100 mg/day PO). Patients with disease progression on letrozole alone could crossover to dasatinib plus continued letrozole. The primary endpoint was clinical-benefit-rate (CBR; complete response + partial response + stable disease ≥6 months). A total of 120 patients were randomized. The CBR of 71% (95% CI 58–83%) was observed with letrozole + dasatinib versus the projected CBR of the combination of 56%. The CBR of 66% (95% CI 52–77%) with letrozole alone also exceeded the projected CBR of 39% with letrozole alone. The CBR was 23% in the crossover arm of letrozole plus dasatinib in patients progressing on letrozole alone. Median progression-free survival with the combination was 20.1 months and 9.9 months with letrozole alone. Letrozole plus dasatinib was well tolerated, although 26% of patients required dasatinib dose reductions. In this non-comparative phase-II trial, the CBR of 71% and the median PFS of 20.1 months with letrozole + dasatinib are encouraging and suggest that dasatinib may inhibit the emergence of acquired resistance to AI therapy.

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