Open-label randomised phase III trial of vinflunine versus an alkylating agent in patients with heavily pretreated metastatic breast cancer.

Background: There is no standard treatment after progression on second-line chemotherapy for metastatic breast cancer (MBC). We compared vinflunine with physician's choice of alkylating agent (AA) for patients with heavily pretreated MBC. Patients and methods: In this open-label phase III trial, patients with MBC were included if they had received at least two prior chemotherapy regimens for MBC and had received anthracycline, taxane, antimetabolite and vinca alkaloid therapy. Patients were no longer candidates for these chemotherapies because of resistance and/or intolerance. Patients were randomised to either vinflunine 280 mg/m2 intravenously every 3 weeks (q3w) or AA monotherapy q3w. Stratification factors were performance status, number of prior chemotherapy lines for MBC, disease measurability and study site. The primary end point was overall survival (OS). Results: A total of 594 patients were randomised (298 to vinflunine, 296 to AA). There was no difference between treatment arms in OS (hazard ratio 1.04, P = 0.67; median 9.1 months for vinflunine versus 9.3 months for AA), progression-free survival (hazard ratio 0.94, P = 0.49; median 2.5 versus 1.9 months, respectively) or overall response rate (6% versus 4%, respectively). However, the disease control rate was significantly higher with vinflunine than AA (44% versus 35%, respectively; P = 0.04). The most common adverse events (any grade) were haematological and gastrointestinal disorders and asthenia in both arms. The most common grade 3/4 adverse events were neutropenia (19% versus 11% with vinflunine versus AA, respectively) and asthenia (10% versus 4%). Conclusions: Vinflunine 280 mg/m2 q3w did not improve OS compared with the physician's choice of AA as third- or later-line therapy for MBC. Vinflunine demonstrated an acceptable safety profile, suggesting that vinflunine 320 mg/m2 merits evaluation. ClinicalTrials.gov: NCT01091168.

Ribociclib plus letrozole in early breast cancer: A presurgical, window-of-opportunity study.

OBJECTIVES: Cyclin D-cyclin-dependent kinase (CDK) 4/6-inhibitor of CDK4/6-retinoblastoma (Rb) pathway hyperactivation is associated with hormone receptor-positive (HR+) breast cancer (BC). This study assessed the biological activity of ribociclib (LEE011; CDK4/6 inhibitor) plus letrozole compared with single-agent letrozole in the presurgical setting. MATERIALS AND METHODS: Postmenopausal women (N = 14) with resectable, HR+, human epidermal growth factor receptor 2-negative (HER2-) early BC were randomized 1:1:1 to receive 2.5 mg/day letrozole alone (Arm 1), or with 400 or 600 mg/day ribociclib (Arm 2 or 3). Circulating tumor DNA and tumor biopsies were collected at baseline and, following 14 days of treatment, prior to or during surgery. The primary objective was to assess antiproliferative response per Ki67 levels in Arms 2 and 3 compared with Arm 1. Additional assessments included safety, pharmacokinetics, and genetic profiling. RESULTS: Mean decreases in the Ki67-positive cell fraction from baseline were: Arm 1 69% (range 38-100%; n = 2), Arm 2 96% (range 78-100%; n = 6), Arm 3 92% (range 75-100%; n = 3). Decreased phosphorylated Rb levels and CDK4, CDK6, CCND2, CCND3, and CCNE1 gene expression were observed following ribociclib treatment. Ribociclib and letrozole pharmacokinetic parameters were consistent with single-agent data. The ribociclib plus letrozole combination was well tolerated, with no Grade 3/4 adverse events over the treatment. CONCLUSION: The results suggest absence of a drug-drug interaction between ribociclib and letrozole and indicate ribociclib plus letrozole may reduce Ki67 expression in HR+, HER2- BC (NCT01919229).