Purpose: Abiraterone may suppress androgens that stimulate breast cancer growth. We conducted a biomarker analysis of circulating tumor cells (CTCs), formalin-fixed paraffin-embedded tissues (FFPETs), and serum samples from postmenopausal estrogen receptor (ER) þ breast cancer patients to identify subgroups with differential abiraterone sensitivity. Methods: Patients (randomized 1:1:1) were treated with 1,000 mg/d abiraterone acetate þ 5 mg/d prednisone (AA), AA þ 25 mg/d exemestane (AAE), or exemestane. The biomarker population included treated patients (n ¼ 293). The CTC population included patients with !3 baseline CTCs (n ¼ 104). Biomarker [e.g., androgen receptor (AR), ER, Ki-67, CYP17] expression was evaluated. Cox regression stratified by prior therapies in the metastatic setting (0/1 vs. 2) and setting of letrozole/anastrozole (adjuvant vs. metastatic) was used to assess biomarker associations with progression-free survival (PFS).Results: Serum testosterone and estrogen levels were lowered and progesterone increased with AA. Baseline AR or ER expression was not associated with PFS in CTCs or FFPETs for AAE versus exemestane, but dual positivity of AR and ER expression was associated with improved PFS [HR, 0.41; 95% confidence interval (CI), 0.16-1.07; P ¼ 0.070]. For AR expression in FFPETs obtained <1 year prior to first dose (n ¼ 67), a trend for improved PFS was noted for AAE versus exemestane (HR, 0.56; 95% CI, 0.24-1.33; P ¼ 0.19).Conclusions: An AA pharmacodynamic effect was shown by decreased serum androgen and estrogen levels and increased progesterone. AR and ER dual expression in CTCs and newly obtained FFPETs may predict AA sensitivity.

11504 Background: Management of chemotherapy-induced nausea and vomiting (CINV) remains challenging. OLN might provide several benefits over APR which is current standard of care – particularly in terms of nausea control and cost effectiveness. However, sedation associated with recommended doses of olanzapine precludes its wide use in oncology practice. Methods: This was randomized phase II single center study aimed to compare OLN and APR in CINV prophylaxis. Key inclusion criteria were: chemo- and radio-therapy naïve patients, planned administration of high-emetogenic chemotherapy (cisplatin, carboplatin AUC≥4, doxorubicin etc). Patients were randomized 1:1 ratio in the following arms: olanzapine 5 QD day 0-4 or aprepitant 125 mg day 1, 80 mg day 2,3. All patients received ondansetron 16 mg day 1 and dexamethasone 8 mg day 1-3. Primary endpoint was complete nausea control (no nausea and no rescue medication) 0-120 hours after chemotherapy. Complete response (no emesis and no rescue medication) was a key secondary end point. Nausea was assessed using MASCC Antiemesis Tool. Sample size: 94 patients to increase nausea control rate from 40 to 70% (α = 0.05; β = 0.80; 10% of estimated data loss). Results: We included in the analysis 93 patients who could be evaluated. The groups were well balanced, median age was 49 years, vast majority of patients (95.6%) were females. The proportion of patients with complete nausea control in OLN and APR groups was 44.2% and 24.0% respectively (RR 2.5; 95% CI 1.04-6.08; p = 0.039). Complete response was achieved in 74.4% and 54.0% patients respectively (RR 2.48; 95% CI 1.026-5.99; p = 0.041). No differences in rates of undesired sedations were detected. Conclusions: Our data suggests superiority of OLN regimen in terms of nausea control. This regimen deserves further investigation. Clinical trial information: NCT03478605.

No abstract

.

Breast cancer (BC) is a malignant tumor originating from the epithelium of the breast tissue. There is no single etiological factor in the development of breast cancer. In 310% of patients with breast cancer, the development of the disease is associated with the presence of mutations in the breast cancer gene (BRCA) 1, BRCA2, CHEK, NBS1, TP53. In other patients, breast cancer is sporadic.