Can trastuzumab emtansine be replaced by additional chemotherapy plus targeted therapy for HER2-overexpressing breast cancer patients with residual disease after neoadjuvant chemotherapy?

A novel antibody-KSP inhibitor conjugate improves KSP inhibitor efficacy in vitro and in vivo

Many clinical trials of kinesin spindle protein (KSP) inhibitors have failed due to issues such as high toxicity and a short circulation half-life in vivo. To address the limitations of current KSP inhibitors and thus broad its use in antitumor therapy, this study applied antibody-drug conjugate (ADC) technology to the KSP inhibitor SB-743921, which was coupled with the HER2-specific antibody trastuzumab using a cathepsin B-dependent valine-alanine (Val-Ala, VA) dipeptide-type linker to generate H2-921. Ex vivo and in vivo analyses of H2-921 showed an increased half-life of SB-743921 and prolonged contact time with tumor cells. Furthermore, H2-921 induced apoptosis and incomplete autophagy in HER2-positive cells. In the in vivo analyses, H2-921 had significant tumor-targeting properties, and tumor inhibition by H2-921 was greater than that by traditional KSP inhibitors but similar to that by the positive control drug T-DM1. In conclusion, this study describes a novel application of ADC technology that enhances the antitumor effects of a KSP inhibitor and thus may effectively address the poor clinical efficacy of KSP inhibitors.

Axillary management in patients with breast cancer and positive axilla at diagnosis. Experience in a Spanish university hospital with a 5-year follow-up

Background

Axillary lymph node dissection (ALND) was the standard in breast cancer with axillary involvement until recently. Along with the number of metastatic nodes, axillary positivity was considered a main prognostic factor and scientific evidence shows that the administration of radiotherapy on ganglion areas decreases the risk of recurrence even in positive axilla. The objective of this study was to evaluate the axillary treatment in patients with positive axilla at diagnosis, the evolution of them over time, and to assess patient's follow-up with the aim of avoiding the morbidity associated with axillary dissection.

Methods

A retrospective observational study of breast cancer patients diagnosed between 2010 and 2017 was performed. In total, 1,100 patients were studied, out of which 168 were women with clinically and histologically positive axilla at diagnosis. Seventy-six percent received primary chemotherapy and subsequent treatment with sentinel node biopsy, axillary dissection, or both. Patients with positive sentinel lymph node biopsy received either radiotherapy or lymphadenectomy depending on the year time they were diagnosed.

Results

For 60 patients out of 168, neoadjuvant chemotherapy resulted in a complete pathological axillary response. Axillary recurrence was registered for six patients. No recurrence was detected in the biopsy group associated with radiotherapy. These results support the benefit of lymph node radiotherapy for patients with positive sentinel node biopsy after receiving primary chemotherapy.

Conclusion

Sentinel node biopsy provides useful and reliable information about cancer staging and might prevent lymphadenectomy, leading to a decrease in morbidity. Pathological response to systemic treatment came out as the most important predictive factor of disease-free survival of breast cancer.

An Elaborate New Linker System Significantly Enhances the Efficacy of an HER2-Antibody-Drug Conjugate against Refractory HER2-Positive Cancers

Human epidermal growth factor receptor 2 (HER2) is overexpressed in breast and gastric cancers and this causes poor clinical outcomes. Although both T-DM1 and Enhertu are approved as an HER2-targeting antibody-drug conjugate (ADC), the effects of these drugs are still not satisfactory to eradicate diverse tumors expressing HER2. To address this shortfall in HER2-targeted therapeutics, an elaborate cleavable linker is created and a novel HER2-targeting ADC composed with trastuzumab and monomethyl auristatin F, which is being investigated in a phase 1 clinical trial and is referred to as LegoChem Bisciences-ADC (LCB-ADC). LCB-ADC displays a higher cytotoxic potency than T-DM1 and it also has a higher G2/M arrest ratio. In animal studies, LCB-ADC produces noticeable tumor growth inhibition compared with trastuzumab or T-DM1 in an HER2 high-expressing N87 xenograft tumor. Especially, LCB-ADC shows good efficacy in terms of suppressing tumor growth in a patient-derived xenograft (PDX) model of HER2-positive gastric cancer as well as in T-DM1-resistant models such as HER2 low-expressing HER2 low expressing JIMT-1 xenograft tumor and PDX. Collectively, the results demonstrate that LCB-ADC with the elaborate linker has a higher efficacy and greater biostability than its ADC counterparts and may successfully treat cancers that are nonresponsive to previous therapeutics.

Effect of level of hormone-receptor expression on treatment outcomes of "triple-positive" early-stage breast cancer

PURPOSE

Breast cancer that overexpresses the human epidermal growth factor receptor-2 (HER2) and both estrogen (ER) and progesterone (PR) receptors is recently recognized as a subtype (triple-positive) with distinctive behavior and response to treatment. In this study, we investigate the treatment outcomes and the beneficial effect of anti-HER2 treatment in relation to level of hormone-receptor (HR) expression.

METHODS

Consecutive breast cancer patients with triple-positive disease, diagnosed, treated and followed at our institution between 2006 and 2016 were enrolled. Disease-free survival (DFS) was studied in relation to the level of HR-positivity.

RESULTS

During the study period, a total of 312 were enrolled; median age (range) was 47 (20-83) years. Fifty (16.0%) of the enrolled patients received adjuvant chemotherapy without trastuzumab (cohort A). All remaining patients were treated with both chemotherapy and trastuzumab and were divided into two groups: Cohort B with both ER and PR scores ≥ 50% (n = 130, 41.7%) and Cohort C with ER and/or PR < 50% (n = 132, 42.3%). After a median follow-up of 47 months, 14 (28.0%), 30 (23.1%) and 20 (15.2%) patients in cohorts A, B, and C had an event in a form of local/system relapse or death while disease-free. The estimated 5-year DFS was 56.2%, 75.4%, and 80.8%, respectively, and at 7 year was 56.2%, 67.1%, and 78.0%, respectively (p < 0.001).

CONCLUSIONS

HER2-positive tumors are not homogeneous; stronger ER/PR co-expression may weaken the beneficial effect of anti-HER2 therapy. Such findings may have potential implication on modifying anti-HER2 treatment based on the strength of HR expression.

Effect of level of hormone-receptor expression on treatment outcomes of "triple-positive" early-stage breast cancer

PURPOSE

Breast cancer that overexpresses the human epidermal growth factor receptor-2 (HER2) and both estrogen (ER) and progesterone (PR) receptors is recently recognized as a subtype (triple-positive) with distinctive behavior and response to treatment. In this study, we investigate the treatment outcomes and the beneficial effect of anti-HER2 treatment in relation to level of hormone-receptor (HR) expression.

METHODS

Consecutive breast cancer patients with triple-positive disease, diagnosed, treated and followed at our institution between 2006 and 2016 were enrolled. Disease-free survival (DFS) was studied in relation to the level of HR-positivity.

RESULTS

During the study period, a total of 312 were enrolled; median age (range) was 47 (20-83) years. Fifty (16.0%) of the enrolled patients received adjuvant chemotherapy without trastuzumab (cohort A). All remaining patients were treated with both chemotherapy and trastuzumab and were divided into two groups: Cohort B with both ER and PR scores ≥ 50% (n = 130, 41.7%) and Cohort C with ER and/or PR < 50% (n = 132, 42.3%). After a median follow-up of 47 months, 14 (28.0%), 30 (23.1%) and 20 (15.2%) patients in cohorts A, B, and C had an event in a form of local/system relapse or death while disease-free. The estimated 5-year DFS was 56.2%, 75.4%, and 80.8%, respectively, and at 7 year was 56.2%, 67.1%, and 78.0%, respectively (p < 0.001).

CONCLUSIONS

HER2-positive tumors are not homogeneous; stronger ER/PR co-expression may weaken the beneficial effect of anti-HER2 therapy. Such findings may have potential implication on modifying anti-HER2 treatment based on the strength of HR expression.