ABSTRACT
Triple-negative breast cancer (TNBC) represents a heterogeneous breast cancer subtype with a poor prognosis. The optimal adjuvant chemotherapy regimen is still unknown. Although numerous large randomized trials have established the benefit of adjuvant anthracyclines and/or taxanes in TNBC, there is no preferred regimen for these patients. There is currently no guideline. Moreover, without knowing the optimal treatment backbone, it will not be possible to evaluate whether adding agents such as platinum or other novel therapies is beneficial for TNBC patients. Furthermore, the best duration of adjuvant treatment in TNBC is still unknown. This review will focus on results of clinical trials that analyzed the benefits of extending the duration of adjuvant treatment in TNBCs with maintenance treatments. We will further discuss promising results in favor of other new agents including capecitabine, metronomic treatment, and biological drugs.
ABSTRACT
BACKGROUND: The NOTCH signaling pathway may be involved in the survival of stem cell-like tumor-initiating cells and contribute to tumor growth. In this phase Ib, open-label, multicenter study (NCT01876251), we evaluated PF-03084014, a selective gamma-secretase inhibitor in patients with advanced triple-negative breast cancer. METHODS: The dose-finding part was based on a 2×3 matrix design using the modified toxicity probability interval method. Oral PF-03084014 was administered twice daily continuously in combination with intravenous docetaxel given on day 1 of each 21-day cycle. Primary endpoint was first-cycle dose-limiting toxicity (DLT) for the dose-finding part and 6-month progression-free survival (PFS) for the expansion cohort treated at the maximum tolerated dose (MTD). Secondary endpoints included safety, objective response, and pharmacokinetics of the combination. RESULTS AND CONCLUSIONS: The MTD was estimated to be PF-03084014 100 mg twice daily / docetaxel 75 mg/m2. At this dose level, combination treatment was generally well tolerated (one DLT, grade 3 diarrhea, among eight DLT-evaluable patients). The most common all-grade, treatment-related adverse events reported in all patients (N = 29) were neutropenia (90%), fatigue (79%), nausea (72%), leukopenia (69%), diarrhea (59%), alopecia (55%), anemia (55%), and vomiting (48%). No effect was observed on the pharmacokinetics of docetaxel when administered in combination with PF-03084014. Four (16%) of 25 response-evaluable patients achieved a confirmed partial response; nine (36%) patients had stable disease, including five patients with unconfirmed partial response. In the expansion cohort, median PFS was 4.1 (95% CI 1.3-8.1) months (6-month PFS rate 17.1% [95% CI 0.8-52.6%]).
