Ribociclib as First-Line Therapy for HR-Positive, Advanced Breast Cancer.

BACKGROUND: The inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) could potentially overcome or delay resistance to endocrine therapy in advanced breast cancer that is positive for hormone receptor (HR) and negative for human epidermal growth factor receptor 2 (HER2). METHODS: In this randomized, placebo-controlled, phase 3 trial, we evaluated the efficacy and safety of the selective CDK4/6 inhibitor ribociclib combined with letrozole for first-line treatment in 668 postmenopausal women with HR-positive, HER2-negative recurrent or metastatic breast cancer who had not received previous systemic therapy for advanced disease. We randomly assigned the patients to receive either ribociclib (600 mg per day on a 3-weeks-on, 1-week-off schedule) plus letrozole (2.5 mg per day) or placebo plus letrozole. The primary end point was investigator-assessed progression-free survival. Secondary end points included overall survival, overall response rate, and safety. A preplanned interim analysis was performed on January 29, 2016, after 243 patients had disease progression or died. Prespecified criteria for superiority required a hazard ratio of 0.56 or less with P<1.29×10-5. RESULTS: The duration of progression-free survival was significantly longer in the ribociclib group than in the placebo group (hazard ratio, 0.56; 95% CI, 0.43 to 0.72; P=3.29×10-6 for superiority). The median duration of follow-up was 15.3 months. After 18 months, the progression-free survival rate was 63.0% (95% confidence interval [CI], 54.6 to 70.3) in the ribociclib group and 42.2% (95% CI, 34.8 to 49.5) in the placebo group. In patients with measurable disease at baseline, the overall response rate was 52.7% and 37.1%, respectively (P<0.001). Common grade 3 or 4 adverse events that were reported in more than 10% of the patients in either group were neutropenia (59.3% in the ribociclib group vs. 0.9% in the placebo group) and leukopenia (21.0% vs. 0.6%); the rates of discontinuation because of adverse events were 7.5% and 2.1%, respectively. CONCLUSIONS: Among patients receiving initial systemic treatment for HR-positive, HER2-negative advanced breast cancer, the duration of progression-free survival was significantly longer among those receiving ribociclib plus letrozole than among those receiving placebo plus letrozole, with a higher rate of myelosuppression in the ribociclib group. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT01958021 .).

Ribociclib with letrozole vs letrozole alone in elderly patients with hormone receptor-positive, HER2-negative breast cancer in the randomized MONALEESA-2 trial.

PURPOSE: Determine the efficacy and safety of first-line ribociclib plus letrozole in elderly patients with HR+, HER2- advanced breast cancer. METHODS: 668 postmenopausal women with HR+, HER2- advanced breast cancer and no prior systemic therapy for advanced disease were enrolled in the Phase III MONALEESA-2 trial (NCT01958021); 295 patients were aged ≥ 65 years. Patients were randomized to ribociclib (600 mg/day; 3-weeks-on/1-week-off) plus letrozole (2.5 mg/day) or placebo plus letrozole until disease progression, unacceptable toxicity, death, or treatment discontinuation. The primary endpoint was PFS, which was evaluated in elderly (≥ 65 years) and younger (< 65 years) patients. Secondary endpoints included response rates and safety. RESULTS: Ribociclib plus letrozole significantly improved PFS vs placebo plus letrozole in elderly (hazard ratio: 0.608; 95% CI 0.394-0.937) and younger patients (hazard ratio: 0.523; 95% CI 0.378-0.723). Overall response rates were numerically higher in the ribociclib vs placebo arm, regardless of age. Ribociclib plus letrozole was well tolerated in elderly patients, with the safety profile similar to the overall study population. Nausea, vomiting, alopecia, and diarrhea were > 10% more frequent in the ribociclib plus letrozole vs placebo plus letrozole arm in both subgroups; most events were grade 1/2. In elderly patients, grade 1/2 anemia and fatigue were > 10% more frequent in the ribociclib plus letrozole vs placebo plus letrozole arm and discontinuation rates were similar in both arms. CONCLUSIONS: Addition of ribociclib to letrozole is a valid therapeutic option for elderly patients with HR+, HER2- advanced breast cancer in the first-line setting.

Dose Delays, Dose Reductions, and Relative Dose Intensity in Patients With Cancer Who Received Adjuvant or Neoadjuvant Chemotherapy in Community Oncology Practices.

BACKGROUND: A wide variety of myelosuppressive chemotherapy regimens are used for the treatment of cancer in clinical practice. Neutropenic complications, such as febrile neutropenia, are among the most common side effects of chemotherapy, and they often necessitate delays or reductions in doses of myelosuppressive agents. Reduced relative dose intensity (RDI) may lead to poorer disease-free and overall survival. METHODS: Using the McKesson Specialty Health/US Oncology iKnowMed electronic health record database, we retrospectively identified the first course of adjuvant or neoadjuvant chemotherapy received by patients without metastases who initiated treatment between January 1, 2007, and March 31, 2011. For each regimen, we estimated the incidences of dose delays (≥7 days in any cycle of the course), dose reductions (≥ 15% in any cycle of the course), and reduced RDI (<85% over the course) relative to the corresponding standard tumor regimens described in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines). RESULTS: This study included 16,233 patients with 6 different tumor types who received 1 of 20 chemotherapy regimens. Chemotherapy dose delays, dose reductions, and reduced RDI were common among patients treated in community oncology practices in the United States, but RDI was highly variable across patients, regimens, and tumor types (0.486-0.935 for standard tumor regimen cohorts). Reduced RDI was more common in older patients, obese patients, and patients whose daily activities were restricted. CONCLUSIONS: In this large evaluation of RDI in US clinical practice, physicians frequently administered myelosuppressive agents at dose intensities lower than those of standard regimens.

Adjuvant docetaxel and cyclophosphamide plus trastuzumab in patients with HER2-amplified early stage breast cancer: a single-group, open-label, phase 2 study.

BACKGROUND: Previous results suggest that docetaxel plus cyclophosphamide improves disease-free survival (DFS) and overall survival compared with doxorubicin plus cyclophosphamide in early stage breast cancer. We assessed the addition of 1 year of trastuzumab to a non-anthracycline regimen, docetaxel plus cyclophosphamide, in patients with HER2-amplified early stage breast cancer and examined whether this regimen was equally effective in patients with TOP2A-amplified and TOP2A-non-amplified disease. METHODS: This was an open-label, single-group, phase 2 study. Eligible patients were aged 18-75 years; had Eastern Cooperative Oncology Group performance status of 1 or less; HER2-amplified early stage breast cancer; operable, histologically confirmed, invasive carcinoma of the breast; adequate tumour specimen available for FISH analysis of TOP2A status; and adequate haematological, renal, hepatic, and cardiac function. Patients received four 21-day cycles of intravenous docetaxel 75 mg/m(2), plus intravenous cyclophosphamide 600 mg/m(2), plus intravenous trastuzumab 4 mg/kg (loading dose) on day 1 and 2 mg/kg on days 1, 8, and 15 during chemotherapy, followed by trastuzumab 6 mg/kg every three weeks for the remainder of 1 year. The primary endpoint was 2-year DFS in TOP2A-amplified and TOP2A-non-amplified patients; the primary analysis was done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00493649. FINDINGS: 493 patients were enrolled between June 15, 2007, and Aug 5, 2009. After a median follow-up of 36·1 months (IQR 35·5-36·7), 2-year DFS was 97·8% (95% CI 94·2-99·2) and 2-year overall survival was 99·5% (95% CI 96·2-99·9) for the 190 patients with TOP2A-amplified disease; 2-year DFS was 97·9% (95% CI 94·9-99·1) and 2-year overall survival was 98·8% (95% CI 96·2-99·6) for the 248 patients with TOP2A-non-amplified disease; 55 patients were not assessable for TOP2A status. In the 486 patients who received at least one dose of study drug, the most common adverse events of any grade were fatigue (284 patients, 58·4%), neutropenia (250, 51·4%), and nausea (217, 44·7%). The most common grade 3-4 toxic effects were neutropenia (229, 47·1%), febrile neutropenia (30, 6·2%), fatigue (21, 4·3%), and diarrhoea (16, 3·3%). Cardiac dysfunction occurred in 29 (6·0%) patients (12 [2·5%] grade 1, 15 [3·1%] grade 2, and two [0·4%] grade 3). 23 patients had at least one study-related serious adverse event. 16 patients stopped trastuzumab because of cardiac dysfunction. INTERPRETATION: A short, four-cycle regimen of docetaxel and cyclophosphamide combined with trastuzumab could be an option for adjuvant treatment of women with lower risk HER2-amplified early breast cancer, irrespective of TOP2A status. FUNDING: Sanofi.

HER2-positive advanced breast cancer.

It is important when treating a patient who has advanced breast cancer to establish the biologic characteristics of the tumor. In addition to knowing the hormone receptor status (estrogen and progesterone), human epidermal receptor 2 (HER2) should be evaluated. The measurement of this parameter is essential to optimizing the systemic management. This article reviews the biology of HER2, testing for HER2, clinical studies evaluating HER2-based therapies, side effects (specifically cardiotoxicity), and strategies for HER2-based therapies.

Multidisciplinary Management of Locally Advanced Breast Cancer.

The treatment of locally advanced breast cancer is aimed at achieving long-term local control with local surgery and/or radiation therapy and at improving disease-free and overall survival through the application of systemic cytotoxic chemotherapy and hormonal therapy. Studies of local therapy alone with surgery or radiotherapy have demonstrated high rates of local recurrence and low rates of long-term survival. The application of anthracycline-based neoadjuvant chemotherapy has resulted in rates of response ranging from 72% to 97%, clinical complete responses of 12-52%, and pathologic complete responses of 4-33%. Multidisciplinary treatment with neoadjuvant therapy, followed by local surgery and/or radiation therapy, followed by additional chemotherapy, has resulted in rates of local control that exceed 80%, and 5-year survival rates exceeding 50% are not unusual. The use of anthracycline-based neoadjuvant chemotherapy in the treatment of locally advanced breast cancer is thus now firmly established. Research in the treatment of locally advanced breast cancer is needed to further define the optimal method of local therapy and the role of new agents such as the taxanes.