RESUMO
BACKGROUND: Dose-dense chemotherapy is one of the treatments of choice for neoadjuvant therapy in breast cancer (BC). Activating mutations in PIK3CA gene predict worse response to neoadjuvant chemotherapy for HER2-positive patients, while their role is less clearly defined for HER2-negative tumors. METHODS: We conducted a phase I/II study of neoadjuvant, sequential, dose-dense anthracycline/taxane chemotherapy, plus trastuzumab in HER2-positive patients and investigated the correlation of pre-treatment PIK3CA mutation status with pathologic complete response (pCR) and long-term outcome in a real-life setting. RESULTS: we established a dose-dense docetaxel recommended dose of 60 mg/m2 and 65 mg/m2, with or without trastuzumab, respectively, according to HER2-status, following dose-dense epirubicin-cyclophosphamide (90/600 mg/m2), every 2 weeks. The overall pCR rate was 21.4%; median disease-free survival (DFS) was 52 months and median overall survival (OS) was not yet reached. PIK3CA mutation status was not significantly associated with the pCR rate: 18% for both mutated and wild-type patients. The pCR rate was: 25% in the mutated and 24% in the wild-type (p 0.560) cohort of the HER2-positive subgroup; 33% both in the mutant and wild-type cohort of the triple-negative subgroup; no pCR neither in the mutant nor in the wild-type cohort of the HR-positive/HER2-negative subgroup. Among the HER2-positive population, a trend toward worse DFS was observed in case of mutation, as opposed to the triple negative population. CONCLUSIONS: This study proposes an effective and safe neoadjuvant dose-dense anthracycline/taxane schedule and suggests that PIK3CA mutation analysis can be usefully performed in real-life clinical practice.
RESUMO
BACKGROUND: Anthracyclines and taxanes are effective drugs in breast cancer (BC), but their toxicity profiles limit their use in combination. A dose-finding study was performed to determine maximum tolerated doses (MTDs) of nonpegylated liposomal doxorubicin (TLC-D99) and docetaxel (DTX) as a dose-dense schedule, to maintain dose intensity, and to limit toxicity, particularly cardiac. METHODS: Twenty-four patients were enrolled, 12 with metastatic BC, 5 with locally advanced BC, and 7 with early BC. An intra- and interpatient approach was planned in two sequential steps. In the first step, TLC-D99 was administered at dose levels of 40, 45, and 50 mg/m(2) plus DTX at a fixed dose of 50 mg/m(2). In the second step, TLC-D99 was administered at the dose established in the first step plus DTX at dose levels of 55, 60, and 65 mg/m(2). Every treatment cycle was delivered on day 1 every 14 days. Pegylated granulocyte colony-stimulating factor was scheduled on day 2. Dose-limiting toxicities (DLTs) were defined as G4 hematological; G3 nonhematological; ≥10% or ≥20% left ventricular ejection fraction (LVEF) reduction if the final value was <50% or ≥50%, respectively; severe arrhythmia; and symptomatic heart failure. LVEF was evaluated by echocardiography every two cycles, and precursor brain natriuretic peptide (pBNP) and cardiac troponin I (cTnI) were monitored on days 1 and 2. RESULTS: Five DLTs occurred (20.8%). No cardiac event of congestive heart failure was reported; 2 events of grade 3 cardiac dysfunction (8.3%), including a ≥20% LVEF reduction in 1 patient and symptomatic arrhythmia in another; 2 incidences of G4 neutropenia (8.3%); and 1 occurrence of G3 asthenia (4.2%) were reported. MTDs were not reached. The recommended doses were established as TLC-D99 50 mg/m(2) and DTX 65 mg/m(2). Cumulatively, mild (G1-G2) cardiac dysfunction was observed in 58.4% of patients: G1 cardiac arrhythmia was noted in 50%, G1-G2 general cardiac toxicity occurred in 25%, and concomitant toxicity was present in 17%. cTnI never increased. pBNP was increased in 25% and was associated with limiting arrhythmia in 4% and cardiac dysfunction in 16%. CONCLUSION: Dose-dense TLC-D99 50 mg/m(2) and DTX 65 mg/m(2) can be safely administered in combination every 2 weeks for breast cancer, with the highest projected dose intensity for each drug at 25 and 32.5 mg/m(2) per week, respectively.
