Association of HER-2/CEP17 Ratio and HER-2 Copy Number With pCR Rate in HER-2-Positive Breast Cancer After Dual-Target Neoadjuvant Therapy With Trastuzumab and Pertuzumab

A Phase II Study of Neoadjuvant PLD/Cyclophosphamide and Sequential nab-Paclitaxel Plus Dual HER2 Blockade in HER2-Positive Breast Cancer

BACKGROUND

Neoadjuvant trastuzumab/pertuzumab (HP) plus chemotherapy for HER2-positive breast cancer (BC) achieved promising efficacy. The additional cardiotoxicity still existed. Brecan study evaluated the efficacy and safety of neoadjuvant pegylated liposomal doxorubicin (PLD)/cyclophosphamide and sequential nab-paclitaxel based on HP (PLD/C/HP-nabP/HP).

PATIENTS AND METHODS

Brecan was a single-arm phase II study. Eligible patients with stages IIA-IIIC HER2-positive BC received 4 cycles of PLD, cyclophosphamide, and HP, followed by 4 cycles of nab-paclitaxel and HP. Definitive surgery was scheduled after 21 days for patients completing treatment or experiencing intolerable toxicity. The primary endpoint was the pathological complete response (pCR).

RESULTS

Between January 2020 and December 2021, 96 patients were enrolled. Ninety-five (99.0%) patients received 8 cycles of neoadjuvant therapy and all underwent surgery with 45 (46.9%) breast-conserving surgery and 51 (53.1%) mastectomy. The pCR was 80.2% (95%CI, 71.2%-87.0%). Four (4.2%) experienced left ventricular insufficiency with an absolute decline in LVEF (43%-49%). No congestive heart failure and ≥grade 3 cardiac toxicity occurred. The objective response rate was 85.4% (95%CI, 77.0%-91.1%), including 57 (59.4%) complete responses and 25 (26.0%) partial responses. The disease control rate was 99.0% (95%CI, 94.3%-99.8%). For overall safety, ≥grade 3 AEs occurred in 30 (31.3%) and mainly included neutropenia (30.2%) and asthenia (8.3%). No treatment-related deaths occurred. Notably, age of >30 (P = .01; OR = 5.086; 95%CI, 1.44-17.965) and HER2 IHC 3+ (P = .02; OR = 4.398; 95%CI, 1.286-15.002) were independent predictors for superior pCR (ClinicalTrials.gov Identifier NCT05346107).

CONCLUSION

Brecan study demonstrated the encouraging safety and efficacy of neoadjuvant PLD/C/HP-nabP/HP, suggesting a potential therapeutic option in HER2-positive BC.

Differential response of HER2-positive breast cancer to anti-HER2 therapy based on HER2 protein expression level

BACKGROUND

Increasing data indicate that HER2-positive (HER2 + ) breast cancer (BC) subtypes exhibit differential responses to targeted anti-HER2 therapy. This study aims to investigate these differences and the potential underlying molecular mechanisms.

METHODS

A large cohort of BC patients (n = 7390) was utilised. The clinicopathological characteristics and differential gene expression (DGE) of HER2+ immunohistochemical (IHC) subtypes, specifically HER2 IHC 3+ and IHC 2 + /Amplified, were assessed and correlated with pathological complete response (pCR) and survival in the neoadjuvant and adjuvant settings, respectively. The role of oestrogen receptor (ER) status was also investigated.

RESULTS

Compared to HER2 IHC 3+ tumours, BC patients with IHC 2 + /Amplified showed a significantly lower pCR rate (22% versus 57%, P < 0.001), shorter survival regardless of HER2 gene copy number, were less classified as HER2 enriched, and enriched for trastuzumab resistance and ER signalling pathway genes. ER positivity significantly decreased response to anti-HER2 therapy in IHC 2 + /Amplified, but not in IHC 3 + BC patients.

CONCLUSION

In HER2 + BC, overexpression of HER2 protein is the driver of the oncogenic pathway, and it is the main predictor of response to anti-HER2 therapy. ER signalling pathways are more dominant in BC with equivocal HER2 expression. personalised anti-HER2 therapy based on IHC classes should be considered.

Effect of the HER-2/CEP17 ratio in IHC 2+/FISH-amplified breast cancer on pathological complete response to neoadjuvant pertuzumab and trastuzumab treatment-a retrospective cohort study

Background

Human epidermal growth factor receptor-2 (HER-2) protein expression level could serve as a predictor of pathological complete response (pCR) to neoadjuvant trastuzumab-containing regimens. The aim of the present study was to evaluate whether pCR to neoadjuvant trastuzumab and pertuzumab treatment is dependent on the level of the HER-2/CEP17 (chromosome enumeration probe 17) ratio in immunohistochemistry (IHC) 2+/fluorescence in situ hybridization (FISH)-amplified breast cancer.

Methods

Patients with primary IHC 2+/FISH-amplified breast cancer who underwent neoadjuvant anti-HER-2 dual-targeted therapies were retrospectively included between January 1, 2020 and May 30, 2021. The primary predictive variable was HER-2/CEP17 ratio, and the primary outcome variable was pCR. Other variables consisted of age, menopausal status, tumor-node-metastasis (TNM) stage, estrogen receptor (ER), progesterone receptor (PgR), and Ki-67. Association between clinicopathologic variables and pCR was evaluated using the chi-square test and logistic regression analysis.

Results

The median age of the patients was 51.78 years (25-67 years), and 50.7% of the patients were in the premenopausal stage. The clinical stage at diagnosis was Stage III in 38 patients (55.1%). Of all patients, 40.6% patients were estrogen receptor positive, and 75.4% patients had a Ki-67 index of ≥30%. The overall pCR (ypN0/isypN0) rate was 31.9%. Patients with HER-2/CEP17 ratio ≥6.0 had a pCR rate of 55.0%, it was statistically higher than 22.4% in patients with HER-2/CEP17 ratio <6.0. Logistic regression analysis confirmed the independent association between HER-2/CEP17 ratio and pCR (P=0.020, OR: 5.203, 95% CI: 1.302-20.783).

Conclusions

A HER-2/CEP17 ratio ≥6.0 might be related to more achievement of pCR in the neoadjuvant anti-HER-2 dual-targeted therapies. Further studies are needed to validate the finding.