Progression-Free Survival for Real-World Use of Palbociclib in Hormone Receptor-Positive Metastatic Breast Cancer.

BACKGROUND: Additional use of cyclin-dependent kinase 4/6 inhibitors with endocrine therapy improves progression-free survival (PFS) in advanced hormone receptor (HR)-positive HER2-negative breast cancer. However, neutropenia is a common reason for dose reductions, leading to concerns about palbociclib efficacy at lower doses. A safety analysis confirmed no PFS differences between palbociclib doses in the second-line setting, but to our knowledge, this has not been evaluated for first-line treatment. PATIENTS AND METHODS: In this retrospective, single-center cohort study we evaluated real-world use of first-line palbociclib with aromatase inhibitor (AI) treatment in HR-positive, HER2-negative metastatic breast cancer patients who received treatment between February 2015 and July 2017. The primary objective was to determine PFS of treatment with palbociclib and an AI in a real-world first-line setting. Secondary objectives included determining the PFS for patients treated with palbociclib on the basis of final doses, time to first dose reduction, time to treatment failure (TTF), and safety. RESULTS: Seventy patients were included in the final analysis. Median PFS was 26.4 months. No significant differences in PFS were observed on the basis of final doses of palbociclib (P = .77). Time to first dose reduction was 2.3 months. Median TTF was 26.1 months. Dose delays, reductions, and Grade 3/4 neutropenia were common (63%, n = 44; 57%, n = 40; and 62%, n = 43, respectively). CONCLUSION: Real-world first-line palbociclib treatment produced outcomes similar to those in PALOMA-2 (Palbociclib and Letrozole in Advanced Breast Cancer) (median PFS 26.4 months vs. 24.8 months) despite more dose reductions (57%, n = 40 vs. 36%, n = 160) and shorter time to first dose reduction (2.3 vs. 3.0 months). No significant differences in PFS were observed for the varying palbociclib doses. Palbociclib dose reductions might not significantly affect PFS in the first-line setting.

Pathological complete response rates with pertuzumab-based neoadjuvant chemotherapy in breast cancer: A single-center experience.

BACKGROUND: Pertuzumab-based neoadjuvant chemotherapy (NAC) has demonstrated successful pathologic complete response (pCR) rates when administered to patients with human epidermal growth factor receptor 2 (HER2)-positive, locally advanced breast cancer and has become standard of care. This study aimed to identify pCR rates in patients receiving a variety of pertuzumab-based NAC regimens. The effect of the addition of an anthracycline and impact of anthracycline and taxane sequencing on pCR was also assessed. METHODS: A retrospective, single-center review was conducted on patients with operable, human epidermal growth factor receptor 2 (HER2)-positive breast cancer that received one of five pertuzumab-containing NAC regimens followed by definitive surgery. RESULTS: Ninety-six patients were included in the analysis; overall, pCR was attained in 49 patients (51%). Of the 61 patients who received an anthracycline-containing NAC regimen, 30 (49%) attained a pCR. Of the 35 patients who received the non-anthracycline NAC regimen, 19 (54%) attained a pCR; difference in pCR was not statistically significant (p = 0.63). Anthracycline/taxane sequence analysis showed that of the patients attaining pCR with an anthracycline-containing NAC, 77% of patients received the taxane portion upfront (p = 0.17). Relative dose intensity of the anthracycline portion was similar irrespective of treatment sequence. However, relative dose intensity of the taxane portion was decreased with upfront anthracycline administration. CONCLUSION: These findings support current recommendations of adding pertuzumab to established regimens for treatment of locally advanced, HER2-positive, early stage breast cancer. The benefit of adding an anthracycline in the neoadjuvant setting remains unclear. Patients treated with the taxane portion of NAC upfront appeared to have a higher rate of pCR and better relative dose intensity than patients who received the anthracycline portion upfront, but differences were not statistically significant. These findings should be verified in a prospective clinical trial.

Time to treatment failure of palbociclib and letrozole as second-line therapy or beyond in hormone receptor-positive advanced breast cancer.

PURPOSE: The management of endocrine therapy resistance is one of the most challenging facets of advanced breast cancer treatment. Palbociclib is an inhibitor of cyclin-dependent kinases 4 and 6 approved for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced or metastatic breast cancer in combination with fulvestrant in postmenopausal women with disease progression following endocrine therapy. However, treatment responsiveness of tumors to palbociclib after multiple lines of endocrine therapy is not clearly established. The purpose of this study was to determine the efficacy of palbociclib and letrozole in patients pretreated with one or more lines of endocrine therapy. METHODS: This was a single-center, retrospective cohort study of all postmenopausal hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer patients who received palbociclib and letrozole as a second-line endocrine therapy or beyond (and no prior cyclin-dependent kinases 4 and 6 inhibitor therapy) between February 1, 2015, and July 31, 2016. The primary objective was to evaluate time to treatment failure of palbociclib in combination with letrozole as a second-line of therapy or beyond. RESULTS: Fifty-three patients meeting eligibility criteria were included in the analysis. For the primary outcome, the median time to treatment failure of palbociclib and letrozole was 6.3 months (95% CI 3.1-7.4 months). Progression-free survival of palbociclib and letrozole therapy was 6.4 months (95% CI 4.9-8.3 months). CONCLUSIONS: Palbociclib and letrozole therapy is a viable, effective treatment option for metastatic breast cancer patients who were not exposed to cyclin-dependent kinases 4 and 6 inhibitors as a first-line endocrine therapy. The benefits of palbociclib and letrozole therapy were seen without excessive toxicity, and although neutropenia was common, it may be managed with dose reduction.

Occurrence and characterization of everolimus adverse events during first and subsequent cycles in the treatment of metastatic breast cancer.

PURPOSE: Endocrine therapy remains the standard therapy for patients with metastatic hormone receptor (HR)-positive breast cancer. The novel combination of everolimus and exemestane has been shown to prolong progression-free survival but with increased adverse events compared to exemestane alone. In this study, we aimed to describe the frequency and timing of everolimus dose reductions and/or interruptions due to adverse events. METHODS: This is a single-center retrospective case series including all patients who received everolimus in combination with exemestane from May 1, 2012, through July 31, 2013. The primary objective was to determine the incidence of first-cycle interruptions or dose reductions with everolimus. RESULTS: Forty-six patients were included in the analysis. First-cycle dose reductions or interruptions were observed in 21 (45.6 %) patients. The most common adverse events leading to dose reduction or interruption was stomatitis (57.1 %), fatigue (14.3 %), and diarrhea (14.3 %). The median time to dose reduction was 14 days, and the median duration of the interruption was 14 days. The median progression-free survival was 6.2 months, and the median time to treatment failure was 4.4 months. CONCLUSIONS: In this case series, almost half of the patients treated with everolimus and exemestane required a dose reduction or interruption of everolimus during the first cycle of treatment. This early onset of adverse events requires thorough patient education and close clinical monitoring during the first 28 days of therapy.

An antimicrobial stewardship program's real-world experience with fidaxomicin for treatment of Clostridium difficile infection: a case series.

STUDY OBJECTIVE: To evaluate real-world clinical and economic outcomes in patients with Clostridium difficile infection (CDI) treated with fidaxomicin. DESIGN: Retrospective case series. SETTING: Academic medical center. PATIENTS: A total of 61 patients with CDI who were treated with fidaxomicin monotherapy or combination therapy from September 2011 to December 2012. MEASUREMENTS AND MAIN RESULTS: Data on demographics, infection characteristics, and clinical and economic outcomes were evaluated. Clinical cure was defined as resolution of diarrhea (less than or equal to three unformed stools for at least 2 consecutive days) maintained for the duration of therapy with no further requirement for CDI therapy and was achieved in 44 (72.1%) patients. Clinical cure was significantly higher for patients receiving fidaxomicin monotherapy compared with fidaxomicin combination therapy (25/29 [86.2%] patients vs 19/32 [59.4%] patients, p=0.04). Clinical cure was similar in patients with a first or prior CDI episode (65.5% vs 78.1%, p=0.27) and in patients with severe versus nonsevere disease (68.4% vs 73.8%, p=0.66). Recurrence occurred in 6 (13.6%) of the 44 patients who achieved clinical cure. Mortality attributable to CDI was 11.5%, and 30-day readmission rate was 4.9%. Median cost accrued during CDI was $19,483/patient. CONCLUSION: Our real-world experience with fidaxomicin significantly differs from the findings of phase III clinical trials. Fidaxomicin is also associated with substantial costs. Multicenter studies are needed to determine the optimal role of fidaxomicin in the treatment of CDI.

Possible correlation of sirolimus plasma concentration with sinusoidal obstructive syndrome of the liver in patients undergoing myeloablative allogeneic hematopoietic cell transplantation.

STUDY OBJECTIVES: To determine the frequency of sinusoidal obstructive syndrome (SOS) in patients undergoing allogeneic hematopoietic cell transplantation who received graft-versus-host disease (GVHD) prophylaxis with sirolimus and tacrolimus, and to assess whether the occurrence of SOS correlates with immunosuppressant levels. DESIGN: Retrospective cohort study. SETTING: Hematopoietic cell transplant unit at an academic medical center. PATIENTS: Fifty-nine adults who received myeloablative preparative regimens for transplantation of any hematologic malignancy and received sirolimus and tacrolimus for GVHD prophylaxis between January 1, 2007, and May 1, 2009; all donors and transplant recipients were human leukocyte antigen (HLA) matched for at least HLA-A, -B, -C, and -DRB1. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the occurrence of SOS after hematopoietic cell transplantation. Plasma concentrations of sirolimus and tacrolimus and the summative levels of sirolimus and tacrolimus were then compared in patients who developed SOS with those who did not develop SOS. Trough levels were measured from blood samples collected 30-60 minutes before the morning doses of sirolimus and tacrolimus on days 0-35, or until the development of SOS. Of the 59 patients, 12 (20%) developed SOS. The mean sirolimus level was significantly higher in patients who developed SOS relative to those who did not develop SOS (10.5 vs 8.7 ng/ml, p=0.003). The mean summative trough level of sirolimus and tacrolimus was also significantly higher in those who developed SOS compared with those who did not (19.7 vs 17.1 ng/ml, p=0.003). The mean ± SD time to the occurrence of SOS was 28 ± 8.7 days. The median time to death was 101 days for patients who developed SOS compared with 433 days for patients who did not develop SOS (p=0.002). CONCLUSION: Sirolimus plasma concentration may correlate with the development of delayed SOS; however, further research is needed to prospectively evaluate the role of sirolimus exposure in the pathogenesis of SOS.

The role of vascular endothelial growth factor SNPs as predictive and prognostic markers for major solid tumors.

Angiogenesis is crucial for development and metastasis of tumors, and vascular endothelial growth factor (VEGF) is a key mediator of this process. The importance of VEGF in tumorigenesis and tumor progression makes it an attractive target for the development of anticancer therapies. Inhibition of angiogenesis has shown promising clinical efficacy; however, not all patients treated with antiangiogenic agents derive benefit from them. Some patients are predisposed to refractory disease, whereas others develop resistance after initial response. Patients may also have different severity of drug-related adverse events. Optimization of drug administration based on disease status and individual responsiveness is important in limiting the treatment failure and minimization of side-effects. Single nucleotide polymorphisms (SNP) in VEGF may alter VEGF protein concentrations, influence the process of angiogenesis, and may relate to interindividual variation in the risk and progression of selected tumors, and their resistance to treatments. This review examines the role of SNPs in the VEGF gene as predictive and prognostic markers for major solid tumors, including the breast, non-small cell lung, colorectal, and prostate cancers. Selected VEGF SNPs seem to be associated with risk of these cancers; however, there is lack of unanimity in findings, in part influenced by differences in study design and analysis.