Neoadjuvant endocrine therapy with or without palbociclib in low-risk patients: a phase III randomized double-blind SAFIA trial.

BACKGROUND: The most prevalent subtype of breast cancer (BC) is luminal hormonal-positive breast cancer. The neoadjuvant chemotherapy regimens have side effects, emphasizing the need to identify new startegies. OBJECTIVE: Analyze the complete pathologic response (pCR) rate and overall response in a low-risk hormone-positive subset of patients receiving neoadjuvant hormone treatment (NAHT) with or without Palbociclib (a CDK4/CDK6 inhibitor) to boost NAHT effectiveness. MATERIALS AND METHODS: Based on the upfront 21-gene Oncotype DX or low-risk Breast Recurrence Score assay (RS™), the SAFIA trial is designed as a prospective multicenter international, double-blind neoadjuvant phase-III trial that selects operable with luminal BC patients that are HER2-negative for the induction hormonal therapy with Fulvestrant 500 mg ± Goserelin (F/G) followed by randomization of responding patients to palbociclib versus placebo. The pCR rate served as the study's main outcome, while the secondary endpoint was a clinical benefit. RESULTS: Of the 354 patients enrolled, 253 initially responded and were randomized to either F/G fulvestrant with palbociclib or placebo. Two hundred twenty-nine were eligible for the evaluation of the pathologic response. No statistically significant changes were observed in the pCR rates for the patients treated with the F/G therapy with placebo or palbociclib (7% versus 2%, respectively) per the Chevallier classification (Class1 + Class2) (p = 0.1464) and 3% versus 10% assessed per Sataloff Classification (TA, NA/NB) (p = 0.3108). Palbociclib did not increase the rate of complete pathological response. CONCLUSION: Neoadjuvant hormonal therapy is feasible in a selected population with a low RS score of < 31 CLINICAL TRIAL: NCT03447132.

Multicentric neoadjuvant pilot Phase II study of cetuximab combined with docetaxel in operable triple negative breast cancer.

Systemic therapy for triple negative breast cancer (TNBC) is mostly based upon chemotherapy. Epithelial Growth Factor Receptor (EGFR) is overexpressed in around 50% of TNBC and may play a role in its pathogenesis. Consequently, we performed a multicentric pilot Phase II neoadjuvant trial of cetuximab (anti-EGFR antibody) combined with docetaxel for patients with operable, Stage II-III TNBC. Therapy consisted of weekly cetuximab (first infusion: 400 mg/m(2), then 250 mg/m(2)) combined with six cycles of docetaxel (T: 100 mg/m(2)) q.3 weeks. Subsequently, all patients underwent surgery. The primary endpoint was pathological complete response (pCR) while clinical response, toxicity and ancillary studies were secondary endpoints. Paraffin-embedded and frozen tumor samples were systematically collected in order to identify predictive biomarkers of efficacy and resistance. From a total of 35 accrued patients, 25 were assessable for pathologic response. The pCR rate was 24% [95% CI: 7.3-40.7]. Complete clinical response rate (cCR) was observed in 22% of cases. Conservative surgery was performed in 75% of patients. Toxicity, mostly cutaneous and hematologic, was manageable. The pre-therapy ratio between CD8+ and FOXP3+ tumor-infiltrating lymphocytes equal or higher than 2.75 was predictive of pCR: 43% versus 0%, p = 0.047. Cetuximab in combination with docetaxel displays a modest activity, but acceptable toxicity as neoadjuvant therapy of operable TNBC. Similarly to previous observations using panitumumab, another anti-EGFR antibody, the immune component of the tumor microenvironment may play an important role in predicting TNBC response to the neoadjuvant therapy.

Multicentric neoadjuvant phase II study of panitumumab combined with an anthracycline/taxane-based chemotherapy in operable triple-negative breast cancer: identification of biologically defined signatures predicting treatment impact.

BACKGROUND: Triple-negative breast cancer (TNBC) is a heterogeneous group of tumors for some of which the epithelial growth factor receptor (EGFR) pathway may play an important role. We investigated the efficacy and toxicity of an anti-EGFR antibody (panitumumab) combined with a standard neoadjuvant anthracycline-taxane-based chemotherapy in patients with operable, stage II-III, TNBC. PATIENTS AND METHODS: Treatment in this multicentric neoadjuvant pilot study consisted of panitumumab (9 mg/kg) for eight cycles q.3 weeks combined with four cycles of 5-fluorouracil, epidoxorubicin and cyclophosphamide (FEC100: 500/100/500 mg/m(2)) q.3 weeks, followed by four cycles of docetaxel (T: 100 mg/m(2)) q.3 weeks. Following therapy, all patients underwent surgical resection. Pathologic complete response (pCR) in assessable patients was the main end point while clinical response, toxicity and ancillary studies were secondary end points. Paraffin-embedded and frozen tumor samples were systematically collected with the aim to identify predictive biomarkers of efficacy and resistance in order to select biologically defined subpopulations for potential further clinical development of the anti-EGFR antibody. RESULTS: Sixty patients were included with 47 assessable for pathologic response. The pCR rates were 46.8% [95% confidence interval (CI): 32.5% to 61.1%] and 55.3% [95% CI: 41.1% to 69.5%] according, respectively, to Chevallier and Sataloff classifications. The complete clinical response (cCR) rate was 37.5%. Conservative surgery was carried out in 87% of cases. Toxicity was manageable. The association of high EGFR and low cytokeratin 8/18 expression in tumor cells on one hand and high density of CD8+ tumor-infiltrating lymphocytes on the other hand were significantly predictive of pCR. CONCLUSIONS: Panitumumab in combination with FEC100 followed by docetaxel appears efficacious, with acceptable toxicity, as neoadjuvant therapy of operable TNBC. Several biomarkers could help define large subsets of patients with a high probability of pCR, suggesting a potential interest to further develop this combination in biologically defined subgroups of patients with TNBC. CLINICAL TRIAL NUMBER: NCT00933517.