High Proliferation Predicts Pathological Complete Response to Neoadjuvant Chemotherapy in Early Breast Cancer.

BACKGROUND: In the neoadjuvant setting, changes in the proliferation marker Ki67 are associated with primary endocrine treatment efficacy, but its value as a predictor of response to chemotherapy is still controversial. PATIENTS AND METHODS: We analyzed 262 patients with centralized basal Ki67 immunohistochemical evaluation derived from 4 GEICAM (Spanish Breast Cancer Group) clinical trials of neoadjuvant chemotherapy for breast cancer. The objective was to identify the optimal threshold for Ki67 using the receiver-operating characteristic curve method to maximize its predictive value for chemotherapy benefit. We also evaluated the predictive role of the defined Ki67 cutoffs for molecular subtypes defined by estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2). RESULTS: A basal Ki67 cutpoint of 50% predicted pathological complete response (pCR). Patients with Ki67 >50% achieved a pCR rate of 40% (36 of 91) versus a pCR rate of 19% in patients with Ki67 ≤ 50% (33 of 171) (p = .0004). Ki67 predictive value was especially relevant in ER-HER2- and ER-HER2+ patients (pCR rates of 42% and 64%, respectively, in patients with Ki67 >50% versus 15% and 45%, respectively, in patients with Ki67 ≤ 50%; p = .0337 and .3238, respectively). Both multivariate analyses confirmed the independent predictive value of the Ki67 cutpoint of 50%. CONCLUSION: Basal Ki67 proliferation index >50% should be considered an independent predictive factor for pCR reached after neoadjuvant chemotherapy, suggesting that cell proliferation is a phenomenon closely related to chemosensitivity. These findings could help to identify a group of patients with a potentially favorable long-term prognosis. IMPLICATIONS FOR PRACTICE: The use of basal Ki67 status as a predictive factor of chemotherapy benefit could facilitate the identification of a patient subpopulation with high probability of achieving pathological complete response when treated with primary chemotherapy, and thus with a potentially favorable long-term prognosis.

Pembrolizumab plus eribulin in hormone-receptor-positive, HER2-negative, locally recurrent or metastatic breast cancer (KELLY): An open-label, multicentre, single-arm, phase â ¡ trial.

BACKGROUND: Pembrolizumab has modest activity if used in patients with hormone-receptor-positive (HR+), HER2-negative, previously treated metastatic breast cancer (BC). Our study investigated whether there would be any clinical benefit in combining chemotherapy with pembrolizumab in a similar patient population. METHODS: This single-arm, phase Ⅱ trial enrolled women aged ≥18 years with HR+, HER2-negative, inoperable, locally recurrent or metastatic BC. Patients were previously treated with hormonal therapy and 1-2 chemotherapy regimens for locally recurrent and/or metastatic BC. On each 21-day cycle, patients received intravenous pembrolizumab 200 mg on day 1 and eribulin 1∙23 mg/m2 on days 1 and 8. The primary endpoint was the clinical benefit rate. Analysis of safety and activity was carried out in all patients who met the screening criteria and received at least 1 dose of study treatment. The trial is registered at ClinicalTrials.gov, NCT03222856. RESULTS: Of the 44 patients enrolled between January 29 and October 17, 2018, clinical benefit was achieved in 25 (56∙8%, 95% confidence interval [CI]: 41∙0-71∙7), objective response in 18 (40∙9%, 95% CI: 26∙3-56∙8), median progression-free survival was 6∙0 months (95% CI: 3∙7-8∙4), and 1-year overall survival was 59∙1% (95% CI: 45∙8-76∙2). The most common treatment-emergent adverse events (AEs) of any grade were neutropenia (20 [45∙5%]), anaemia (17 [38∙6%]), alopecia (19 [43∙2%]), asthenia (19 [43∙2%]), diarrhoea (14 [31∙8%]), fatigue (14 [31∙8%]), and peripheral neuropathy (12 [27∙3%]). Serious AEs occurred in 14 (31∙8%) patients including febrile neutropenia (3 [6∙8%]), neutropenia (2 [4∙5%]), fever (2 [4∙5%]) and peripheral neuropathy (2 [4∙5%]). Immune-related AEs occurred in 11 (25∙0%) patients. One (2∙3%) patient died of cardiac arrest unrelated to study treatment. CONCLUSION: Pembrolizumab plus eribulin demonstrates encouraging antitumour activity in patients with heavily pre-treated, HR+, HER2-negative, locally recurrent or metastatic BC. The safety and tolerability of the combination is similar to eribulin or pembrolizumab monotherapy.