Leptin regulation of the p53-HIF1α/PKM2-aromatase axis in breast adipose stromal cells: a novel mechanism for the obesity-breast cancer link.

BACKGROUND/OBJECTIVES: Obesity (body mass index (BMI)⩾30 kg m-2) is associated with an increased risk of estrogen-dependent breast cancer after menopause. Levels of aromatase, the rate-limiting enzyme in estrogen biosynthesis, are elevated in breast tissue of obese women. Recently, the regulation of aromatase by the p53-hypoxia-inducible factor-1α (HIF1α)/pyruvate kinase M2 (PKM2) axis was characterized in adipose stromal cells (ASCs) of women with Li-Fraumeni Syndrome, a hereditary cancer syndrome that predisposes to estrogen-dependent breast cancer. The current study aimed to determine whether stimulation of aromatase by obesity-associated adipokine leptin involves the regulation of the p53-HIF1α/PKM2 axis. SUBJECTS/METHODS: Human breast ASCs were used to characterize the p53-HIF1α/PKM2-aromatase axis in response to leptin. The effect of pharmacological or genetic modulation of protein kinase C (PKC), mitogen-activated protein kinase (MAPK), p53, Aha1, Hsp90, HIF1α and PKM2 on aromatase promoter activity, expression and enzyme activity was examined. Semiquantitative immunofluorescence and confocal imaging were used to assess ASC-specific protein expression in formalin-fixed paraffin-embedded tissue sections of breast of women and mammary tissue of mice following a low-fat (LF) or high-fat (HF) diet for 17 weeks. RESULTS: Leptin-mediated induction of aromatase was dependent on PKC/MAPK signaling and the suppression of p53. This, in turn, was associated with an increase in Aha1 protein expression, activation of Hsp90 and the stabilization of HIF1α and PKM2, known stimulators of aromatase expression. Consistent with these findings, ASC-specific immunoreactivity for p53 was inversely associated with BMI in breast tissue, while HIF1α, PKM2 and aromatase were positively correlated with BMI. In mice, HF feeding was associated with significantly lower p53 ASC-specific immunoreactivity compared with LF feeding, while immunoreactivity for HIF1α, PKM2 and aromatase were significantly higher. CONCLUSIONS: Overall, findings demonstrate a novel mechanism for the obesity-associated increase in aromatase in ASCs of the breast and support the study of lifestyle interventions, including weight management, which may reduce breast cancer risk via effects on this pathway.

Research needs in breast cancer.

New research questions emerge as medical needs continue to evolve and as we improve our understanding of cancer biology and treatment of malignancies. Although significant advances have been made in some areas of breast cancer research resulting in improvements in therapies and outcomes over the last few decades, other areas have not benefited to the same degree and we continue to have many gaps in our knowledge. This article summarizes the 12 short and medium-term clinical research needs in breast cancer deemed as priorities in 2016 by a panel of experts, in an attempt to focus and accelerate future research in the most needed areas: (i) de-escalate breast cancer therapies in early breast cancer without sacrificing outcomes; (ii) explore optimal adjuvant treatment durations; (iii) develop better tools and strategies to identify patients with genetic predisposition; (iv) improve care in young patients with breast cancer; (v) develop tools to speed up drug development in biomarker-defined populations; (vi) identify and validate targets that mediate resistance to chemotherapy, endocrine therapy and anti-HER2 therapies; (vii) evaluate the efficacy of local-regional treatments for metastatic disease; (viii) better define the optimal sequence of treatments in the metastatic setting; (ix) evaluate the clinical impact of intra-patient heterogeneity (intra-tumor, inter-tumor and inter-lesion heterogeneity); (x) better understand the biology and identify new targets in triple-negative breast cancer; (xi) better understand immune surveillance in breast cancer and further develop immunotherapies; and (xii) increase survivorship research efforts including supportive care and quality of life.

Risk of acute myeloid leukemia and myelodysplastic syndrome among older women receiving anthracycline-based adjuvant chemotherapy for breast cancer on Modern Cooperative Group Trials (Alliance A151511).

PURPOSE: We examined acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) events among 9679 women treated for breast cancer on four adjuvant Alliance for Clinical Trials in Oncology trials with >90 months of follow-up in order to better characterize the risk for AML/MDS in older patients receiving anthracyclines. METHODS: We used multivariable Cox regression to examine factors associated with AML/MDS, adjusting for age (≥65 vs. <65 years; separately for ≥70 vs. <70 years), race/ethnicity, insurance, performance status, and anthracycline receipt. We also examined the effect of cyclophosphamide, the interaction of anthracycline and age, and outcomes for those developing AML/MDS. RESULTS: On Cancer and Leukemia Group B (CALGB) 40101, 49907, 9344, and 9741, 7290 received anthracyclines; 15% were in the age ≥65 and 7% were ≥70. Overall, 47 patients developed AML/MDS (30 AML [0.3%], 17 MDS [0.2%]); 83% of events occurred within 5 years of study registration. Among those age ≥65 and ≥70, 0.8 and 1.0% developed AML/MDS (vs. 0.4% for age <65), respectively. In adjusted analyses, older age and anthracycline receipt were significantly associated with AML/MDS (adjusted hazard ratio [HR] for age ≥65 [vs. <65] = 3.13, 95% confidence interval [CI] 1.18-8.33; HR for anthracycline receipt [vs. no anthracycline] = 5.16, 95% CI 1.47-18.19). There was no interaction between age and anthracycline use. Deaths occurred in 70% of those developing AML/MDS. CONCLUSIONS: We observed an increased risk for AML/MDS for older patients and those receiving anthracyclines, though these events were rare. Our results help inform discussions surrounding anticipated toxicities of adjuvant chemotherapy in older patients.

Weekly paclitaxel with trastuzumab and pertuzumab in patients with HER2-overexpressing metastatic breast cancer: overall survival and updated progression-free survival results from a phase II study.

We previously reported progression-free survival (PFS) results on a phase II trial of weekly paclitaxel, trastuzumab, and pertuzumab in patients with human epidermal growth factor receptor 2(HER2)-positive metastatic breast cancer (MBC) treated in the first- and second-line setting. Here, we report results for overall survival (OS) and updated PFS after an additional year of follow-up. Patients with HER2-positive MBC with 0-1 prior treatment were eligible. Treatment consisted of paclitaxel (80 mg/m(2)) weekly, and trastuzumab (loading dose 8 mg/kg â†’ 6 mg/kg) and pertuzumab (loading dose 840 mg â†’ 420 mg) every 3 weeks, all given intravenously. Primary endpoint was 6-month PFS. Secondary endpoints included median PFS, 6-month and median OS. Evaluable patients received at least one full dose of treatment. From January 2011 to December 2013, 69 patients were enrolled: 51 (74 %) and 18 (26 %) treated in first- and second-line metastatic settings, respectively. As of July 1, 2015, the median follow-up was 33 months (range 3-49 months; 67 patients were evaluable for efficacy). The median OS was 44 months (95 % CI 37.5-NR) overall and 44 months (95 % CI 38.3-NR) and 37.5 months (95 % CI 30.3-NR) for patients with 0 and 1 prior metastatic treatment, respectively; 6-month OS was 98 % (95 % CI 90-1). The 6-month PFS was 86 % (95 % CI 75-93) overall and 89 % (95 % CI 76-95) and 78 % (95 % CI 51-91) for patients with 0 and 1 prior therapy, respectively; and median PFS was 21.4 months (95 % CI 14.1-NR) overall and 25.7 months (95 % CI 14.1-NR) and 16.9 months (95 % CI 8.5-NR) for patients with 0-1 prior treatment, respectively. Treatment was well tolerated. Updated analysis demonstrates that weekly paclitaxel, when added to trastuzumab and pertuzumab, is associated with a favorable OS and PFS and offers an alternative to docetaxel-based therapy. http://www.ClinicalTrials.gov NCT0127604.

Predicting response and survival in chemotherapy-treated triple-negative breast cancer.

BACKGROUND: In this study, we evaluated the ability of gene expression profiles to predict chemotherapy response and survival in triple-negative breast cancer (TNBC). METHODS: Gene expression and clinical-pathological data were evaluated in five independent cohorts, including three randomised clinical trials for a total of 1055 patients with TNBC, basal-like disease (BLBC) or both. Previously defined intrinsic molecular subtype and a proliferation signature were determined and tested. Each signature was tested using multivariable logistic regression models (for pCR (pathological complete response)) and Cox models (for survival). Within TNBC, interactions between each signature and the basal-like subtype (vs other subtypes) for predicting either pCR or survival were investigated. RESULTS: Within TNBC, all intrinsic subtypes were identified but BLBC predominated (55-81%). Significant associations between genomic signatures and response and survival after chemotherapy were only identified within BLBC and not within TNBC as a whole. In particular, high expression of a previously identified proliferation signature, or low expression of the luminal A signature, was found independently associated with pCR and improved survival following chemotherapy across different cohorts. Significant interaction tests were only obtained between each signature and the BLBC subtype for prediction of chemotherapy response or survival. CONCLUSIONS: The proliferation signature predicts response and improved survival after chemotherapy, but only within BLBC. This highlights the clinical implications of TNBC heterogeneity, and suggests that future clinical trials focused on this phenotypic subtype should consider stratifying patients as having BLBC or not.

Phase III trial of nonpegylated liposomal doxorubicin in combination with trastuzumab and paclitaxel in HER2-positive metastatic breast cancer.

BACKGROUND: Nonpegylated liposomal doxorubicin liposomal doxorubicin, (Myocet™; Sopherion Therapeutics, Inc Canada, and Cephalon, Europe) (NPLD; Myocet(®)) in combination with trastuzumabHerceptin(®) (Hoffmann-La Roche) has shown promising activity and cardiac safety. We conducted a randomized phase III trial of first-line NPLD plus trastuzumab and paclitaxel (Pharmachemie B.V.) (MTP) versus trastuzumab plus paclitaxel (TP) in patients with human epidermal growth factor 2 receptor (HER2)-positive metastatic breast cancer. PATIENTS AND METHODS: Patients were randomly assigned to NPLD (M, 50 mg/m(2) every 3 weeks for six cycles), trastuzumab (T, 4 mg/kg loading dose followed by 2 mg/kg weekly), and paclitaxel (P, 80 mg/m(2) weekly) or T + P at the same doses until progression or toxicity. The primary efficacy outcome was progression-free survival (PFS). RESULTS: One hundred and eighty-one patients were allocated to receive MTP, and 183 to TP. Median PFS was 16.1 and 14.5 months with MTP and TP, respectively [hazard ratio (HR) 0.84; two-sided P = 0.174]. In patients with estrogen receptor (ER)- and progesterone receptor (PR)-negative tumors, PFS was 20.7 and 14.0 months, respectively [HR 0.68; 95% confidence interval (CI) 0.47-0.99]. Median overall survival (OS) was 33.6 and 28.9 months with MTP and TP, respectively (HR 0.79; two-sided P = 0.083). In ER- and PR-negative tumors, OS was 38.2 and 27.9 months, respectively (HR 0.63; 95% CI 0.42-0.93). The frequency of adverse events was higher with MTP, but there was no significant difference in cardiac toxicity between treatment arms. CONCLUSION(S): The trial failed to demonstrate a significant clinical improvement with the addition of M to TP regimen. The clinical benefit observed in an exploratory analysis in the ER- and PR-negative population deserves consideration for further clinical trials. CLINICAL TRIAL NUMBER: NCT00294996.

Polygenic inheritance of paclitaxel-induced sensory peripheral neuropathy driven by axon outgrowth gene sets in CALGB 40101 (Alliance).

Peripheral neuropathy is a common dose-limiting toxicity for patients treated with paclitaxel. For most individuals, there are no known risk factors that predispose patients to the adverse event, and pathogenesis for paclitaxel-induced peripheral neuropathy is unknown. Determining whether there is a heritable component to paclitaxel-induced peripheral neuropathy would be valuable in guiding clinical decisions and may provide insight into treatment of and mechanisms for the toxicity. Using genotype and patient information from the paclitaxel arm of CALGB 40101 (Alliance), a phase III clinical trial evaluating adjuvant therapies for breast cancer in women, we estimated the variance in maximum grade and dose at first instance of sensory peripheral neuropathy. Our results suggest that paclitaxel-induced neuropathy has a heritable component, driven in part by genes involved in axon outgrowth. Disruption of axon outgrowth may be one of the mechanisms by which paclitaxel treatment results in sensory peripheral neuropathy in susceptible patients.

Persistence, adherence, and toxicity with oral CMF in older women with early-stage breast cancer (Adherence Companion Study 60104 for CALGB 49907).

BACKGROUND: Cyclophosphamide-methotrexate-5-fluorouracil (CMF) is often selected as adjuvant chemotherapy for older patients with early-stage breast cancer due to perceived superior tolerability. We sought to measure persistence with CMF, adherence to oral cyclophosphamide, and the association of these with toxic effects. PATIENTS AND METHODS: CALGB 49907 was a randomized trial comparing standard chemotherapy (CMF or AC, provider/patient choice) with capecitabine in patients aged ≥65 with stage I-IIIB breast cancer. Those randomized to standard therapy and choosing CMF were prescribed oral cyclophosphamide 100 mg/m(2) for 14 consecutive days in six 28-day cycles. Persistence was defined as being prescribed six cycles of at least one of the three CMF drugs. Adherence was the number of cyclophosphamide doses that women reported they had taken divided by the number prescribed. Persistence and adherence were based on case report forms and medication calendars. RESULTS: Of 317 randomized to standard chemotherapy, 133 received CMF. Median age was 73 (range 65-88). Seventy-one percent submitted at least one medication calendar; 65% persisted with CMF. Non-persistence was associated with node negativity (P = 0.019), febrile neutropenia (P = 0.002), and fatigue (P = 0.044). Average adherence was 97% during prescribed cycles. CONCLUSIONS: Self-reported adherence to cyclophosphamide was high, but persistence was lower, which may be attributable to toxic effects.

A phase I study of dasatinib and weekly paclitaxel for metastatic breast cancer.

BACKGROUND: SRC plays an important role in the pathogenesis of metastatic breast cancer (MBC). In preclinical models, paclitaxel and the oral SRC inhibitor dasatinib showed greater antitumor activity than either agent. To determine the maximum tolerated dose of this combination, we conducted a phase I study. PATIENTS AND METHODS: Patients with MBC; Eastern Cooperative Oncology Group performance status of zero to one; normal hepatic, renal and marrow function were eligible. Paclitaxel 80 mg/m(2) was given 3 weeks of 4. The starting dasatinib dose was 70 mg and was increased, using a standard 3 + 3 dose-escalation scheme. RESULTS: Fifteen patients enrolled (median age 54 years, range 35-74). No dose-limiting toxic effects (DLTs) occurred at dasatinib doses of 70-120 mg. One DLT (grade 3 fatigue) occurred in the dasatinib 150-mg cohort, which was expanded (six patients) with no further DLTs. However, due to cumulative toxic effects (rash, fatigue, diarrhea), the recommended phase II dose is dasatinib 120 mg. Of 13 assessable patients, a partial response was seen in 4 patients (31%), including 2 patients previously treated with taxanes; all received ≥120 mg dasatinib. An additional five patients (29%) had stable disease. CONCLUSION: In combination with weekly paclitaxel, the recommended phase II dose of dasatinib is 120 mg daily and preliminary activity has been seen in patients with MBC.

Breast carcinoma with brain metastases: clinical analysis and immunoprofile on tissue microarrays.

BACKGROUND: Development of brain metastasis in patients with breast carcinoma correlates with poor outcome. Identification of tumor characteristics associated with breast cancer brain metastases (BCBM) could help identify patients at risk. PATIENTS AND METHODS: We studied 209 patients with BCBM. We evaluated a panel of proteins relevant to the biology of breast carcinoma on tissue microarrays of 133 primary tumors and 56 BCBM, including paired samples from 43 patients, and correlated the findings with the clinical outcome. RESULTS: The median survival after BCBM diagnosis was 19 months (95% confidence interval, 13-23 months). Patients presenting with solitary metastasis had a significantly longer median survival than those with multiple lesions (25 versus 11 months, P ≤ 0.0001). We found no significant discordance in the expression of tested markers, but identified a possible association between the expression of basal cytokeratin CK5/6 in the primary carcinoma and the development of multiple rather than solitary brain metastases. CONCLUSIONS: Expression of antigens commonly associated with breast carcinoma does not differ significantly between the primary tumor and the corresponding brain metastases. Although no specific immunoprofile identifies breast carcinomas that develop brain metastases, we observed a possible association between CK5/6 expression in the primary tumor and multiple versus solitary BCBM.

Periprostatic adipose inflammation is associated with high-grade prostate cancer.

BACKGROUND: Obesity, a cause of subclinical inflammation, is associated with increased risk of high-grade prostate cancer (PC) and poor outcomes. Whether inflammation occurs in periprostatic white adipose tissue (WAT), and contributes to the negative impact of obesity on PC aggressiveness, is unknown. METHODS: In a single-center, cross-sectional design, men with newly diagnosed PC undergoing radical prostatectomy were eligible for study participation. The primary objective was to examine the prevalence of periprostatic WAT inflammation defined by the presence of crown-like structures (CLS-P) as detected by CD68 immunohistochemistry. Secondary objectives were to explore the clinical and systemic correlates of periprostatic WAT inflammation. Tumor characteristics and host factors including BMI, adipocyte diameter, and circulating levels of lipids, adipokines, and other metabolic factors were measured. Wilcoxon rank-sum, Chi-square, or Fisher's exact tests, and generalized linear regression were used to examine the association between WAT inflammation and tumor and host characteristics. RESULTS: Periprostatic fat was collected from 169 men (median age 62 years; median BMI 28.3). Periprostatic WAT inflammation was identified in 49.7% of patients and associated with higher BMI (P=0.02), larger adipocyte size (P=0.004) and Gleason grade groups IV/V tumors (P=0.02). The relationship between WAT inflammation and high Gleason grade remained significant after adjusting for BMI (P=0.04). WAT inflammation correlated with higher circulating levels of insulin, triglycerides, and leptin/adiponectin ratio, and lower high density lipoprotein cholesterol, compared to those without WAT inflammation (P's <0.05). CONCLUSION: Periprostatic WAT inflammation is common in this cohort of men with PC and is associated with high-grade PC.

An on-site audit of the South African trial of high-dose chemotherapy for metastatic breast cancer and associated publications.

PURPOSE: The randomized study reported by Bezwoda et al of high-dose chemotherapy (HDC) for treatment of metastatic breast cancer was audited on site to verify the study results. Additional published studies were reviewed to determine whether they had been subject to the required institutional oversight. PATIENTS AND METHODS: Ninety patients were reported to have been randomized and treated on this trial. A log of the names, hospital numbers, entry dates, and regimen received had been provided by the principal investigator. A search of more than 15,000 sets of medical records available from two Johannesburg hospitals was performed to locate records for as many of these 90 patients as possible. Standard auditing techniques were used. Additional clinical trials published by Bezwoda were compared against the minutes of the University of the Witwatersrand Committee for Research on Human Subjects to verify review and approval. RESULTS: Records for only 61 of the 90 patients could be found. Of these 61, only 27 had sufficient records to verify eligibility for the trial by the published criteria. Of these 27, 18 did not meet one or more eligibility criteria. Only 25 patients appeared to have received their assigned therapy temporally associated with their enrollment date, and all but three of these 25 received HDC. The treatment details of individual patients were at great variance from the published data. Nine other trials reported by Bezwoda were not reviewed or approved by the appropriate institutional committee despite statements to the contrary in the publications. CONCLUSION: The multiple publications of this study do not report verifiable data, and nine other publications coauthored by the principal investigator contain at least one major untrue statement.

Paclitaxel and recombinant human granulocyte colony-stimulating factor as initial chemotherapy for metastatic breast cancer.

PURPOSE: A phase II study of Taxol (paclitaxel; Bristol-Myers Squibb Co, Princeton, NJ) as initial chemotherapy for metastatic breast cancer was conducted. Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was used to ameliorate myelosuppression, the anticipated dose-limiting toxicity. PATIENTS AND METHODS: Twenty-eight patients with bidimensionally measurable breast cancer who had not received prior chemotherapy for metastatic disease were treated. Taxol was administered at 250 mg/m2 as a continuous 24-hour intravenous (i.v.) infusion every 21 days. rhG-CSF was administered at 5 micrograms/kg/d subcutaneously on days 3 through 10. RESULTS: Objective responses were observed in 16 of 26 assessable patients (62%; 95% confidence interval, 41% to 80%). There were three (12%) complete responses (CRs) and 13 (50%) partial responses (PRs). Ten of 16 patients (63%) who had received prior adjuvant chemotherapy responded, which included one CR and four PRs among eight patients who had received prior doxorubicin-containing therapy. Responses were observed in all sites of metastatic disease. The median time to first objective response was 5 weeks (range, 1 to 14). Administration of rhG-CSF was associated with a short duration of neutropenia (median, 2 days with absolute neutrophil count < 500 cells/microL). Eight of 26 patients (31%) who received more than one course received subsequent therapy without dose reduction. One hundred seventy-eight cycles of treatment were administered, with a median of six cycles per patient (range, one to 19). Eight courses (4.5%) were associated with admissions for neutropenic fever. Twenty-two patients (79%) did not require admission for neutropenic fever. Treatment was well tolerated. Adverse effects included generalized alopecia in all patients. Myalgias, arthralgias, and peripheral neuropathy were mild. No hypersensitivity reactions and no cardiac toxicity were observed. CONCLUSION: Taxol is highly active as initial chemotherapy for metastatic breast cancer. Administration of rhG-CSF reduced the incidence, depth, and duration of neutropenia, compared with published prior experience. Further studies of Taxol in breast cancer, including combinations with other active agents, are clearly warranted.

Paclitaxel as second and subsequent therapy for metastatic breast cancer: activity independent of prior anthracycline response.

PURPOSE: Two phase II clinical trials were performed to determine efficacy and tolerability of paclitaxel (Taxol; Bristol-Myers Squibb Co, Wallingford, CT) and granulocyte colony-stimulating factor ([G-CSF] Neupogen; Amgen, Inc, Thousand Oaks, CA) as second or subsequent therapy for metastatic breast cancer. PATIENTS AND METHODS: Paclitaxel plus G-CSF was administered as a second stage IV regimen to 25 patients with metastatic breast cancer at a dose of 250 mg/m2 intravenously over 24 hours. Fifty-two patients received paclitoxel plus G-CSF at 200 mg/m2 as a third or subsequent regimen (no restriction on number of prior regimens or on prior high-dose chemotherapy). All patients had received prior anthracycline treatment, and ultimately had progressive bidimensionally measurable disease. RESULTS: Twenty-five of 76 patients (32.8%) had a major objective response (95% confidence interval [CI], 14% to 37%). The median duration of response was 7 months (range, 1 to 20+). Responses were as likely in patients with disease demonstrated to be unresponsive to anthracycline, ie, de novo resistance (11 of 37, or 30%) as in those with disease that once exhibited anthracycline sensitivity, ie, acquired resistance, (10 of 31, or 32%). G-CSF administration was associated with febrile neutropenic episodes in 36 of 402 cycles (9%) in 16 of 76 patients (21%). CONCLUSION: Paclitaxel's clinically significant activity against metastatic breast cancer extends to patients with many prior chemotherapy regimens. The lack of impact of prior doxorubicin therapy on the likelihood of subsequent response to paclitaxel suggests an important role for this agent in the treatment of refractory metastatic breast cancer.

Dose-dense therapy with weekly 1-hour paclitaxel infusions in the treatment of metastatic breast cancer.

PURPOSE: To evaluate the efficacy and toxicity of paclitaxel administered as a 1-hour infusion on weekly basis, without interruption, to patients with metastatic breast cancer who had received prior therapy. PATIENTS AND METHODS: Thirty patients with metastatic breast cancer received sustained weekly paclitaxel therapy at an initial dose of 100 mg/m2 until disease progression. Prior therapy included adjuvant only (n=17), metastatic only (n=7), or both (n=6). Eighteen patients had received prior anthracycline therapy, 12 of whom had demonstrated progression of disease within 12 months of it. All patients were assessable for efficacy; 29 patients were assessable for toxicity. Pharmacokinetic studies of paclitaxel were also performed. RESULTS: A total of 469 weekly paclitaxel infusions were administered to 30 patients (median, 14 infusions/patient). The median delivered dose-intensity was 91 mg/m2/wk (range, 80 to 108). The overall response rate was 53% (95% confidence interval [CI], 34% to 72%), with 10% complete responses (CRs) and 43% partial responses (PRs). Median response duration was 7.5 months (range, 2 to 11+). Responses were observed in nine of 18 (50%) patients with prior anthracycline therapy, including six of 12 (50%) with disease progression on anthracycline within 1 year (three of four within 6 months). Therapy was well tolerated and remarkable for a lack of overall and cumulative myelosuppression. Grade 3/4 neutropenia occurred in four patients; febrile neutropenia was not observed. Peripheral neuropathy prohibited dose escalation above 100 mg/m2, and grade 3 neuropathy was observed in two of 21 patients at < or = 100 mg/m2. CONCLUSION: Weekly paclitaxel therapy is active and well tolerated in patients with metastatic breast cancer. Weekly therapy should be considered as a current clinical option for these patients and should be incorporated into future comparative clinical trials.

Phase II study of weekly intravenous recombinant humanized anti-p185HER2 monoclonal antibody in patients with HER2/neu-overexpressing metastatic breast cancer.

PURPOSE: Breast cancer frequently overexpresses the product of the HER2 proto-oncogene, a 185-kd growth factor receptor (p185HER2). The recombinant humanized monoclonal antibody (rhuMAb) HER2 has high affinity for p185HER2 and inhibits the growth of breast cancer cells that overexpress HER2. We evaluated the efficacy and toxicity of weekly intravenous administration of rhuMAb HER2 in patients with HER2-overexpressing metastatic breast cancer. PATIENTS AND METHODS: We treated 46 patients with metastatic breast carcinomas that overexpressed HER2. Patients received a loading dose of 250 mg of intravenous rhuMAb HER2, then 10 weekly doses of 100 mg each. Patients with no disease progression at the completion of this treatment period were offered a maintenance phase of 100 mg/wk. RESULTS: Study patients had extensive metastatic disease, and most had received extensive prior anticancer therapy. Adequate pharmacokinetic levels of rhuMAb HER2 were obtained in 90% of the patients. Toxicity was minimal and no antibodies against rhuMAb HER2 were detected in any patients. Objective responses were seen in five of 43 assessable patients, and included one complete remission and four partial remissions (overall response rate, 11.6%; 95% confidence interval, 4.36 to 25.9). Responses were observed in liver, mediastinum, lymph nodes, and chest wall lesions. Minor responses, seen in two patients, and stable disease, which occurred in 14 patients, lasted for a median of 5.1 months. CONCLUSION: rhuMAb HER2 is well tolerated and clinically active in patients with HER2-overexpressing metastatic breast cancers that had received extensive prior therapy. This is evidence that targeting growth factor receptors can cause regression of human cancer and justifies further evaluation of this agent.

Phase II and pharmacologic study of docetaxel as initial chemotherapy for metastatic breast cancer.

PURPOSE: Because docetaxel (Taxotere, RP 56976; Rhone-Poulenc Rorer, Antony, France) appeared to be active against breast cancer in phase I trials, we performed this phase II study. PATIENTS AND METHODS: Thirty-seven patients with measurable disease were enrolled. Only prior hormone therapy was allowed, as was adjuvant chemotherapy completed > or = 12 months earlier. Docetaxel 100 mg/m2 was administered over 1 hour every 21 days. Diphenhydramine hydrochloride and/or corticosteroid premedication was added after hypersensitivity-like reactions (HSRs) were seen in two of the first six patients. Pharmacokinetic studies were performed during cycle 1 for correlation with toxicity. RESULTS: Thirty-seven patients were assessable. Nineteen (51%) required dose reductions, usually for neutropenic fever. The median nadir WBC count was 1.4 x 10(3)/microL. HSRs were noted in 20 patients (54%). At a median cumulative dose of 297 mg/m2 (range, 99.6 to 424.5 mg/m2), 30 patients (81%) developed fluid retention, for which 11 (30%) subsequently stopped treatment. The first-cycle plasma area under the concentration-time curve (AUC) did not correlate with toxicity, although an ineligible patient with hepatic metastases (pretreatment bilirubin level 1.8 mg/dL) had an elevated AUC and died of toxicity. Responses were seen at all sites. On an intent-to-treat basis, there were two (5%) complete responses (CRs) and 18 (49%) partial responses (PRs). The overall response proportion (CRs plus PRs) was 54% (95% confidence interval, 37% to 71%). The median time to response was 12 weeks (range, 3 to 15) and the median duration was 26 weeks (range, 10 to 58+). CONCLUSION: Docetaxel is active for metastatic breast cancer. Neutropenia and fluid retention are dose-limiting. The AUC did not predict toxicity, but caution is warranted when treating patients with liver dysfunction. An understanding of the pathophysiology of the fluid retention may facilitate prevention. Frequent HSR may warrant prophylactic premedication.

Ninety-six-hour paclitaxel infusion after progression during short taxane exposure: a phase II pharmacokinetic and pharmacodynamic study in metastatic breast cancer.

PURPOSE: A phase II trial of paclitaxel infused over 96 hours in patients with metastatic breast cancer with demonstrated disease progression (PD) during short-infusion taxane treatment was performed to evaluate schedule-dependent activity with prolonged drug exposure. The tolerability of this strategy and its pharmacokinetic profile and pharmacodynamic correlates were also investigated. PATIENTS AND METHODS: Paclitaxel was administered to 26 patients with metastatic breast cancer at 120 to 140 mg/m2 intravenously over 96 hours. Twenty-three patients had demonstrated PD while receiving prior 3-hour paclitaxel, two during 1-hour docetaxel, and one during infusions of docetaxel and then paclitaxel. Twenty-one patients (81%) had no prior response to the short taxane infusion (primary resistance) and five (19%) had prior partial responses (PRs) of brief duration before PD (secondary resistance). Plasma paclitaxel concentrations were assessed at 24, 48, 72, and 96 hours. RESULTS: After delivery of 195 cycles, seven of 26 assessable patients (26.9%; 95% confidence interval, 11.6% to 47.8%) had major objective responses, with a median response duration of 6 months (range, 1 to 13). The predominant toxicities were neutropenia (76% grade > or = 3) and stomatitis (15% grade > or = 3). Despite omission of premedications, no significant hypersensitivity reactions occurred. The median steady-state paclitaxel concentration (Css) in 23 assessable patients was 0.047 mumol/L (range, .023 to .176). Patients who experienced grade 4 neutropenia had significantly decreased paclitaxel clearance and higher Css than those with grade 1 to 3 neutropenia (P < .05). Pretreatment elevation of hepatic transaminases was associated with delayed clearance (P < .01) and increased myelo-suppression and mucosal toxicity. CONCLUSION: Paclitaxel demonstrates activity against metastatic breast cancer when administered over 96 hours to patients with disease that recently had progressed during short taxane exposure. Delayed paclitaxel clearance and consequent increased toxicity occurred in patients with hepatic dysfunction. The activity observed supports preclinical data that suggest variability in efficacy and resistance patterns to paclitaxel based on duration of exposure.