HER2-positive advanced breast cancer: optimizing patient outcomes and opportunities for drug development.

Effective targeting of the human epidermal growth factor receptor 2 (HER2) has changed the natural history of HER2 overexpressing (HER2+) metastatic breast cancer. The initial success of trastuzumab improving time to progression and survival rates led to the clinical development of pertuzumab, ado-trastuzumab emtansine and lapatinib. These biologic therapies represent significant additions to the breast medical oncology armamentarium. However, drug resistance ultimately develops and most tumours progress within 1 year. Ongoing studies are evaluating novel therapeutic approaches to overcome primary and secondary drug resistance in tumours, including inhibition of PI3K/TOR, HSP90, IGF-IR and angiogenesis. Mounting experimental data support the clinical testing of immune checkpoint modulators and vaccines. The central nervous system remains a sanctuary site for HER2+ breast cancer and further studies are needed for the prevention and treatment of brain metastases in this population. Despite efforts to identify predictors of preferential benefit from HER2-targeted therapies (e.g., truncated HER2, PTEN loss and SRC activation), HER2 protein overexpression and/or gene amplification remains the most important predictive factor of response to HER2-targeted therapies. In this article, we review the optimal sequence of HER2-targeted therapies and describe ongoing efforts to improve the outcome of HER2+ advanced breast cancer through rational drug development.

Clinical benefit from neoadjuvant chemotherapy in oestrogen receptor-positive invasive ductal and lobular carcinomas.

BACKGROUND: The aim of this study was to compare clinical and pathological outcomes after neoadjuvant chemotherapy between oestrogen receptor (ER)-positive invasive pure lobular carcinoma (ILC) and invasive ductal carcinoma (IDC). METHODS: This analysis included 1895 patients (n=177 ILC; n=1718 IDC), with stage I-III breast cancer, who received neoadjuvant chemotherapy. Clinical and pathological response rates, the frequency of positive surgical margins and rate of breast-conserving surgery were compared. RESULTS: There was a trend for fewer good clinical responses in ILC compared with IDC. Tumour downstaging was significantly less frequent in ILC. Positive or close surgical resection margins were more frequent in ILC, and breast-conserving surgery was less common (P<0.001). These outcome differences remained significant in multivariate analysis, including tumour size, nodal status, age, grade and type of chemotherapy. Invasive pure lobular carcinoma was also associated with a significantly lower pathological complete response (pCR) rate in univariate analysis, but this was no longer significant after adjusting for tumour size and grade. CONCLUSION: Neoadjuvant chemotherapy results in lower rates of clinical benefit, including less downstaging, more positive margins and fewer breast-conserving surgeries in ER-positive ILC compared with ER-positive IDC. Pathological complete responses are rare in both groups, but do not significantly differ after adjusting for other variables.

Metformin and thiazolidinediones are associated with improved breast cancer-specific survival of diabetic women with HER2+ breast cancer.

BACKGROUND: Insulin/insulin-like growth factor-I (IGF-I) signaling is a mechanism mediating the promoting effect of type 2 diabetes (DM2) on cancer. Human epidermal growth factor receptor (HER2), insulin receptor and IGF-I receptor involve the same PI3K/AKT/mTOR signaling, and different antidiabetic pharmacotherapy may differentially affect this pathway, leading to different prognoses of HER2+ breast cancer. METHODS: We reviewed 1983 consecutive patients with HER2+ breast cancer treated between 1 January 1998 and 30 September 2010. The overall survival, breast cancer-specific death rate, age, race, nuclear grade, stage, menopausal status, estrogen and progesterone receptor status, body mass index and classes of antidiabetic pharmacotherapy were analyzed. RESULTS: A Cox regression analysis showed that DM2 [P=0.026, hazard ratio (HR)=1.42, 95 % confidence interval (95 % CI) 1.04-1.94] predicted poor survival of stage≥2 HER2+ breast cancer. In Kaplan-Meier analysis, metformin predicted lengthened survival and so did thiazolidinediones. Analyzing only the diabetics, Cox regression showed that metformin (P=0.041, HR=0.52, 95 % CI 0.28-0.97) and thiazolidinediones (P=0.036; HR=0.41, 95% CI 0.18-0.93) predicted lengthened survival, and competing risk analysis showed that metformin and thiazolidinediones were associated with decreased breast cancer-specific mortality (P=0.023, HR=0.47, 95% CI 0.24-0.90 and P=0.044, HR=0.42, 95 % CI 0.18-0.98, respectively). CONCLUSIONS: Thiazolidinediones and metformin users are associated with better clinical outcomes than nonusers in diabetics with stage≥2 HER2+ breast cancer. The choice of antidiabetic pharmacotherapy may influence prognosis of this group.

Association between the nuclear to cytoplasmic ratio of p27 and the efficacy of adjuvant polychemotherapy in early breast cancer.

BACKGROUND: The purpose of this study was to evaluate the prognostic and predictive value of p27 expression in patients with early breast cancer. PATIENTS AND METHODS: Quantitative immunofluorescence assays for p27 were done on a tissue microarray that included 823 samples from patients randomized between anthracycline-based chemotherapy and no chemotherapy. Quantification of p27 was done using the AQUA® system (HistoRx, Inc., Branford, CT). Both p27 nuclear expression and the nuclear to cytoplasmic ratio were assessed. RESULTS: Nuclear p27 expression was not predictive for the efficacy of anthracycline-based chemotherapy [adjusted P=0.18 for disease-free survival (DFS)] nor prognostic [95% confidence interval (CI) 0.99-1.01, P=0.49]. However, p27 nuclear/cytoplasmic ratio was predictive for the efficacy of adjuvant chemotherapy (adjusted P=0.016 DFS). The adjusted hazard ratio (HR) for relapse associated with adjuvant chemotherapy was 0.56 (95% CI 0.37-0.84, P=0.005) and 1.06 (95% CI 0.76-1.47, P=0.74) for patients with high and low nuclear/cytoplasmic ratio, respectively. p27 N/C ratio was prognostic in patients treated with chemotherapy (HR for relapse or death for a 1 unit increase in p27 N/C ratio was 0.30, 95% CI 0.12-0.77) but not in the untreated arm (HR for relapse or death was 1.27, 95% CI 0.58-2.8). CONCLUSIONS: This study did not confirm the role of p27 nuclear expression as a prognostic parameter. However, the p27 nuclear/cytoplasmic ratio was predictive in patients treated with anthracycline-based chemotherapy.

LncRNA RP11-19E11 is an E2F1 target required for proliferation and survival of basal breast cancer.

Long non-coding RNAs (lncRNAs) play key roles in the regulation of breast cancer initiation and progression. LncRNAs are differentially expressed in breast cancer subtypes. Basal-like breast cancers are generally poorly differentiated tumors, are enriched in embryonic stem cell signatures, lack expression of estrogen receptor, progesterone receptor, and HER2 (triple-negative breast cancer), and show activation of proliferation-associated factors. We hypothesized that lncRNAs are key regulators of basal breast cancers. Using The Cancer Genome Atlas, we identified lncRNAs that are overexpressed in basal tumors compared to other breast cancer subtypes and expressed in at least 10% of patients. Remarkably, we identified lncRNAs whose expression correlated with patient prognosis. We then evaluated the function of a subset of lncRNA candidates in the oncogenic process in vitro. Here, we report the identification and characterization of the chromatin-associated lncRNA, RP11-19E11.1, which is upregulated in 40% of basal primary breast cancers. Gene set enrichment analysis in primary tumors and in cell lines uncovered a correlation between RP11-19E11.1 expression level and the E2F oncogenic pathway. We show that this lncRNA is chromatin-associated and an E2F1 target, and its expression is necessary for cancer cell proliferation and survival. Finally, we used lncRNA expression levels as a tool for drug discovery in vitro, identifying protein kinase C (PKC) as a potential therapeutic target for a subset of basal-like breast cancers. Our findings suggest that lncRNA overexpression is clinically relevant. Understanding deregulated lncRNA expression in basal-like breast cancer may lead to potential prognostic and therapeutic applications.

Survival among women with triple receptor-negative breast cancer and brain metastases.

BACKGROUND: The purpose of this study was to determine the incidence of and survival following brain metastases among women with triple receptor-negative breast cancer. PATIENTS AND METHODS: In all, 679 patients with nonmetastatic triple receptor-negative breast cancer diagnosed from 1980 to 2006 were identified. Cumulative incidence of brain metastases was computed. Cox proportional hazards models were fitted to explore factors that predict for development of brain metastases. Survival was computed using the Kaplan-Meier product limit method. RESULTS: Median follow-up was 26.9 months. In all, 42 (6.2%) patients developed brain metastases with a cumulative incidence at 2 and 5 years of 5.6% [95% confidence interval (CI) 3.8% to 7.9%] and 9.6% (95% CI 6.8% to 13%), respectively. A total of 24 (3.5%) patients developed brain metastases as the first site of recurrence with cumulative incidence at 2 and 5 years of 2.0% (95% CI 2.6% to 6.0%) and 4.9% (95% CI 3.2% to 7.0%), respectively. In the multivariable model, no specific factor was observed to be significantly associated with time to brain metastases. Median survival for all patients who developed brain metastases and those who developed brain metastases as the first site of recurrence was 2.9 months (95% CI 2.0-7.6 months) and 5.8 months (95% CI 1.7-11.0 months), respectively. CONCLUSION: In this single-institutional study, patients with nonmetastatic triple receptor-negative breast tumors have a high early incidence of brain metastases associated with poor survival and maybe an ideal cohort to target brain metastases preventive strategies.

Efficacy and safety of CT-P6 versus reference trastuzumab in HER2-positive early breast cancer: updated results of a randomised phase 3 trial.

PURPOSE: Neoadjuvant CT-P6, a trastuzumab biosimilar, demonstrated equivalent efficacy to reference trastuzumab in a phase 3 trial of HER2-positive early-stage breast cancer (EBC) (NCT02162667). We report post hoc analyses evaluating pathological complete response (pCR) and breast pCR alongside additional efficacy and safety measures. METHODS: Following neoadjuvant treatment and surgery, patients received adjuvant CT-P6 or trastuzumab (6 mg/kg) every 3 weeks for ≤ 1 year. RESULTS: In total, 271 and 278 patients received CT-P6 and trastuzumab, respectively. pCR and breast pCR rates were comparable between treatment groups regardless of age, region, or clinical stage. Overall, 47.6% (CT-P6) and 52.2% (trastuzumab) of patients experienced study drug-related treatment-emergent adverse events (TEAEs), including 17 patients reporting heart failure (CT-P6: 10; trastuzumab: 7). Two CT-P6 and three trastuzumab patients discontinued adjuvant treatment due to TEAEs. CONCLUSION: Adjuvant CT-P6 demonstrated comparable efficacy and safety to trastuzumab at 1 year in patients with HER2-positive EBC, supporting CT-P6 and trastuzumab comparability.

Trastuzumab: triumphs and tribulations.

The human epidermal growth factor receptor 2 (HER2) tyrosine kinase receptor is overexpressed in approximately 20-30% of human breast cancers, and is associated with reduced survival. Hence, numerous therapeutic strategies have been tested for their ability to target the HER2 protein. The humanized monoclonal antibody trastuzumab (Herceptin) was the first HER2-targeted agent approved for clinical use in breast cancer patients. Response rates to single-agent trastuzumab range from 12 to 34% for metastatic breast cancer (MBC), and significant improvements in survival rates are achieved in patients with early-stage HER2-overexpressing breast cancer in the adjuvant setting. Despite its initial efficacy, acquired resistance to trastuzumab develops in a majority of patients with MBC, and a large subset never responds, demonstrating primary resistance. Molecular mechanisms of trastuzumab antineoplastic activity and potential mechanisms contributing to its resistance will be discussed in this review. Novel agents that may enhance trastuzumab efficacy will also be discussed.

Defining prognosis for women with breast cancer and CNS metastases by HER2 status.

BACKGROUND: The purpose of this retrospective study was to determine, in a cohort of patients with breast cancer and central nervous system (CNS) metastases, the effect of trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive disease and to compare this with that of patients with HER2-negative disease. METHODS: Five hundred and ninety-eight patients with invasive breast cancer, CNS metastases and known HER2 status were identified. Time to CNS metastases and survival after CNS metastases were estimated by the Kaplan-Meier method, and Cox models were fitted to determine the association between HER2 status, trastuzumab treatment and outcomes after adjustment for other patient characteristics. RESULTS: In the multivariable model, patients with HER2-negative disease [Hazard ratio (HR) 1.50, 95% confidence interval (CI) 1.15-1.95, P = 0.003] and patients with HER2-positive disease who did not receive trastuzumab (HR 2.13, 95% CI 1.51-3.00, P < 0.0001) had shorter times to CNS metastases compared with patients with HER2-positive disease who had received trastuzumab as first-line therapy for metastases. Furthermore, patients with HER2-negative disease (HR 1.66, 95% CI 1.31-2.12, P < 0.0001) and patients with HER2-positive disease who had never received trastuzumab (HR 1.34, 95% CI 0.78-2.30, P = 0.28) had an increased hazard of death compared with patients with HER2-positive disease who had received trastuzumab before or at the time of CNS metastases diagnosis. CONCLUSION: In our cohort of patients with breast cancer and CNS metastases, patients with HER2-positive disease treated with trastuzumab had longer times to development of and better survival from CNS metastases compared with patients with HER2-positive disease who had never received trastuzumab and patients with HER2-negative breast cancer.

Expression patterns and predictive value of phosphorylated AKT in early-stage breast cancer.

BACKGROUND: AKT phosphorylation is a critical step in the activation of growth factor receptors and can mediate tumor resistance to anthracyclines. We evaluated the expression patterns and predictive value of phosphorylated AKT (pAKT) in breast cancer tissues. PATIENTS AND METHODS: pAKT expression was assessed by immunohistochemistry in 823 tumors from patients with early breast cancer enrolled in two randomized trials. The distribution of pAKT expression was correlated with HER2 and epidermal growth factor receptor (EGFR) expression. The predictive value of pAKT for the efficacy of adjuvant chemotherapy was determined by test for interaction. RESULTS: pAKT, EGFR, and HER2 were expressed in 119 of 781 (15%), 118 of 758 (16%), and 99 of 775 (13%) assessable tumors. Staining was positive for pAKT in 28 of 99 (28%) and 90 of 676 (13%) HER2+ and HER2- tumors (P < 0.001). pAKT was expressed in 15 of 94 (16%) and 75 of 563 (13%) HER2-/EGFR+ and HER2-/EGFR- tumors, respectively (P = 0.49). A positive staining for pAKT did not correlate with prognosis (P = 0.94), and did not predict the resistance to anthracyclines (test for interaction, P = 0.70). CONCLUSIONS: AKT phosphorylation is associated with HER2 expression but not EGFR expression in patients with early breast cancer. pAKT is not predictive for the efficacy of anthracycline-based adjuvant chemotherapy.

Hormone receptor status and pathologic response of HER2-positive breast cancer treated with neoadjuvant chemotherapy and trastuzumab.

BACKGROUND: The aim of this study was to compare the extent of pathologic response in patients with HER2-positive (HER2+) breast cancer treated with standard neoadjuvant chemotherapy, with or without trastuzumab (H), according to hormone receptor (HR) status. PATIENTS AND METHODS: We included 199 patients with HER2+ breast cancer from three successive cohorts of neo-adjuvant chemotherapy on the basis of paclitaxel (Taxol) (P) administered weekly (w) or three weekly (3-w), followed by 5-fluorouracil (F), doxorubicin (A) or epirubicin (E), and cyclophosphamide (C). Residual cancer burden (RCB) was determined from pathologic review of the primary tumor and lymph nodes and was classified as pathologic complete response (pCR) or minimal (RCB-I), moderate (RCB-II), or extensive (RCB-III) residual disease. RESULTS: In HR-positive (HR+) cancers, a higher rate of pathologic response (pCR/RCB-I) was observed with concurrent H + 3-wP/FEC (73%) than with 3-wP/FEC (34%, P = 0.002) or wP/FAC (47%; P = 0.02) chemotherapy alone. In HR-negative (HR-) cancers, there were no significant differences in the rate of pathologic response (pCR/RCB-I) from 3-wP/FAC (50%), wP/FAC (68%), or concurrent H + 3-wP/FEC (72%). CONCLUSIONS: Patients with HR+/HER2+ breast cancer obtained significant benefit from addition of trastuzumab to P/FEC chemotherapy; pathologic response rate was similar to that seen in HR-/HER2+ breast cancers.

Comparative assessment of lipid effects of endocrine therapy for breast cancer: implications for cardiovascular disease prevention in postmenopausal women.

Cardiovascular disease (CVD) is the leading cause of death in the developed world for both men and women. Women experience significant alterations in lipid profiles during the years following menopause, including a reduction in plasma high-density lipoprotein cholesterol and an elevation of plasma low-density lipoprotein cholesterol, and are at an increased risk of CVD. These changes are due in part to the reduction in estrogen production following the onset of the menopause. Therefore, agents that have anti-estrogenic effects, such as most endocrine therapies for breast cancer, may increase the risk of CVD. Tamoxifen, historically the standard endocrine therapy, has an overall beneficial effect on lipid profiles. However, long-term data from clinical trials have failed to demonstrate a cardioprotective effect and patients treated with tamoxifen did not experience fewer cardiovascular events compared with those receiving placebo. Indeed, a number of studies have shown that tamoxifen may have a detrimental effect, with a significantly increased risk of venous thromboembolic events, pulmonary embolism and stroke. The third-generation aromatase inhibitors (AIs) have demonstrated an improvement in efficacy and tolerability over previous treatments. Since they have a different mechanism of action to tamoxifen, they are not anticipated to exert the same impact on lipid profiles. Clinical trials with anastrozole demonstrated no clinically relevant impact on lipid profiles in postmenopausal patients with advanced breast cancer. However, as lipid profiles are surrogate endpoints, the most appropriate endpoint is the incidence of cardiovascular events in long-term studies. This is of particular relevance in the treatment of early breast cancer, where endocrine agents may be used in the adjuvant setting for periods of 5 years or more. Long-term adjuvant anastrozole treatment resulted in significantly fewer thromboembolic and cerebrovascular events and a similar incidence of ischemic cardiovascular events compared with tamoxifen. The effects of the other AIs on lipid levels are variable, and any correlation with cardiovascular events is currently unknown.

Safety and efficacy of bisphosphonates beyond 24 months in cancer patients.

PURPOSE: Bisphosphonate therapy has decreased the risk of skeletal complications associated with osteolytic bone lesions in patients with breast cancer and multiple myeloma. The large prospective studies have used 21 to 24 months of treatment. We studied the safety and efficacy of bisphosphonates in a subset of patients who received therapy for more than 24 months. PATIENTS AND METHODS: Patients who received bisphosphonates (pamidronate or zoledronic acid) were identified. Data on skeletal events and laboratory parameters were gathered by chart review. RESULTS: We studied 22 patients who received intravenous pamidronate or zoledronic acid for a duration of 3.6 years (range, 2.2 to 6.0 years). Prolonged therapy was well tolerated. No significant calcium, phosphorus, electrolyte, or WBC count abnormalities were encountered. There was a clinically insignificant decrease in hemoglobin and platelet count and an increase in creatinine in these patients. The fracture rate beyond 2 years was no greater than during the first 2 years of treatment. There were no stress fractures of long bones with prolonged therapy. CONCLUSION: Prolonged treatment with the potent bisphosphonates pamidronate and zoledronic acid seems to be well tolerated and should be studied in prospective, randomized studies to document prolonged skeletal efficacy.

Impact of systemic treatment on local control for patients with lymph node-negative breast cancer treated with breast-conservation therapy.

PURPOSE: To determine the impact of tamoxifen and chemotherapy on local control for breast cancer patients treated with breast-conservation therapy. PATIENTS AND METHODS: The data from 484 breast cancer patients who were treated with breast-conserving surgery and radiation were analyzed. Only patients with lymph node-negative disease were studied to provide comparative groups with a similar stage of disease and a similar competing risk for distant metastases. Actuarial local control rates of the 277 patients treated with systemic therapy (128, chemotherapy with or without tamoxifen; 149, tamoxifen alone) were compared with the rates for the 207 patients who received no systemic treatment. Only 10% of the patients had positive (2%), close (3%), or unknown margin status (5%). RESULTS: Patients treated with systemic therapy had improved 5-year (97.5% v 89.8%) and 8-year (95.6% v 85.2%) local control rates compared with those that did not receive systemic treatment (P =.004, log-rank test). There was no statistical difference in local control between patients treated with chemotherapy and patients treated with tamoxifen alone (P =.219). Systemic treatment, margin status, young patient age, estrogen and progesterone receptor status, and primary tumor size were analyzed in a Cox regression analysis. The use of systemic treatment was the most powerful predictor of local control: patients who did not receive systemic treatment had a relative risk of local recurrence of 3.3 (95% confidence interval, 1.5 to 7.5; P =.004). CONCLUSION: In this retrospective analysis, systemic therapy appears to contribute to long-term local control in patients with lymph node-negative breast cancer treated with breast-conservation therapy.

Phase I study of stealth liposomal doxorubicin in combination with gemcitabine in the treatment of patients with metastatic breast cancer.

PURPOSE: We conducted a single-institution phase I clinical trial to determine the maximum-tolerated dose (MTD) and define the toxic effects of stealth liposomal doxorubicin in combination with gemcitabine in patients with metastatic breast cancer. PATIENTS AND METHODS: Patients were eligible if they had disease progression with no limit on prior number of chemotherapy regimens. Prior treatment with liposomal doxorubicin and/or gemcitabine was not allowed. The starting dose of liposomal doxorubicin was 20 mg/m(2) on day 1 only with a 20% dose escalation of the previous mg/m(2) dose until MTD was reached. Gemcitabine was given as a fixed dose of 800 mg/m(2) on days 1 and 8 every 3 weeks. RESULTS: We treated 27 patients of whom six had never received chemotherapy for their disease. Most had had visceral involvement as their dominant site of disease. The dose-limiting toxicity was myelosuppression, which included neutropenia and thrombocytopenia. However, neither neutropenic fever nor episodes of bleeding were major occurrences. Significant antitumor activity was also observed with a total of two complete and seven partial responses. The recommended phase II dose is liposomal doxorubicin 24 mg/m(2) on day 1 and gemcitabine 800 mg/m(2) on days 1 and 8 every 21 days. CONCLUSION: The combination of liposomal doxorubicin and gemcitabine is an active and well tolerated regimen when administered on a 21-day schedule. Myelosuppression limited further dose escalation, however, it did not increase the incidence of neutropenic fever. Significant antitumor activity seen in heavily and minimally pretreated patients warrants further evaluation of this combination.

Weekly trastuzumab and paclitaxel therapy for metastatic breast cancer with analysis of efficacy by HER2 immunophenotype and gene amplification.

PURPOSE: This phase II study evaluated weekly trastuzumab and paclitaxel therapy in women with HER2-normal and HER2-overexpressing metastatic breast cancer. Efficacy was correlated with immunohistochemical and fluorescent in situ hybridization (FISH) assay results. PATIENTS AND METHODS: Eligible patients had bidimensionally measurable metastatic breast cancer. Up to three prior chemotherapy regimens, including prior anthracycline and taxane therapy, were allowed. Trastuzumab 4 mg/kg and paclitaxel 90 mg/m2 were administered on week 1, with trastuzumab 2 mg/kg and paclitaxel 90 mg/m2 administered on subsequent weeks. HER2 status was evaluated using four different immunohistochemical assays and FISH. RESULTS: Patients received a median of 25 weekly infusions (range, one to 85 infusions). Median delivered paclitaxel dose-intensity was 82 mg/m2/wk (range, 52 to 90 mg/m2/wk). The intent-to-treat response rate for all 95 patients enrolled was 56.8% (95% confidence interval, 47% to 67%). A response rate of 61.4% (4.5% complete response, 56.8% partial response) was observed in 88 fully assessable patients. In patients with HER2-overexpressing tumors, overall response rates ranged from 67% to 81% compared with 41% to 46% in patients with HER2-normal expression (ranges reflect the different assay methods used to assess HER2 status). Differences in response rates between patients with HER2-overexpressing tumors and those with normal HER2 expression were statistically significant for all assay methods, with CB11 and TAB250 antibodies and FISH having the strongest significance. Therapy was generally well tolerated, although three patients had serious cardiac complications. CONCLUSION: Weekly trastuzumab and paclitaxel therapy is active in women with metastatic breast cancer. Therapy was relatively well tolerated; however, attention to cardiac function is necessary.

Chemo-signal therapy, an emerging new approach to modify drug resistance in breast cancer.

Recent advances in understanding how response or resistance to cytotoxic drugs develops at the cellular level resulted in the development of novel, non-cytotoxic agents that modulate response the chemotherapy. 'Chemo-signal therapy', the combination of chemotherapy with cellular response modifiers, is a very promising new treatment modality that has entered the arena of clinical trials. Clinical experience with the anti-HER-2 antibody, trastuzumab, in breast cancer has demonstrated that manipulation of growth factor signalling can enhance sensitivity to cytotoxic drugs in a clinically meaningful way. Several other agents that were designed to modulate response to chemotherapy are currently in early phases of clinical drug development. It is likely that some of these new molecules will have a major impact on how chemotherapy will be given in the next decade. This paper will review current clinical research with a select group of chemotherapy response modifiers. We will focus on agents that modulate signal transduction, oncogene expression and apoptosis with an emphasis on breast cancer.

Trastuzumab in combination with chemotherapy for the treatment of metastatic breast cancer.

Metastatic breast carcinoma still remains an incurable condition. The relentless search for novel agents that might prove useful for management has evolved toward monoclonal antibodies, in part because of a rapidly expanding understanding of breast cancer biology. Trastuzumab (Herceptin; Genentech, Inc, South San Francisco, CA) is a recombinant humanized monoclonal antibody against the HER-2 receptor that has shown antitumor activity as a single agent in phase I and II trials of patients with metastatic breast cancer overexpressing HER-2. The observation of increased antitumor activity between trastuzumab and some chemotherapeutic agents in preclinical models has prompted its use in combination with several drugs. Of particular interest is the use of trastuzumab with paclitaxel. Two trials were presented at the 1999 meeting of the American Society of Clinical Oncology that evaluated this combination. One multicenter phase III trial showed clinical benefit and increased survival for patients with HER-2-overexpressing metastatic breast cancer treated with chemotherapy plus trastuzumab. A phase II trial, reviewed in this report, evaluated the efficacy and safety of weekly paclitaxel plus trastuzumab for patients with metastatic breast carcinoma, including those overexpressing and nonoverexpressing HER-2.

Phase II trial and pharmacokinetic evaluation of cytosine arabinoside for leptomeningeal metastases from breast cancer.

PURPOSE: To determine the efficacy and pharmacokinetics of intraventricular cytosine arabinoside (Ara-C) as front-line treatment for leptomeningeal metastases from breast cancer. METHODS: Ten patients newly diagnosed with leptomeningeal metastases (LMM) from breast cancer were treated with 100 mg intraventricular cytosine arabinoside (IVT Ara-C) via an Ommaya reservoir. Treatment was administered three times a week for 2 weeks, then once a week for 4 weeks, and then once every 6 weeks for four cycles to responding patients. Nine patients were evaluable clinically, and seven patients underwent testing to determine the pharmacokinetic profile of Ara-C in the cerebrospinal fluid (CSF). RESULTS: Two patients had partial responses lasting 9 and 40 weeks, respectively. Two other patients had stable disease. The median survival duration was 30 weeks (range: 5-58 weeks). Seven patients died from LMM. Acute toxic effects associated with IVT Ara-C included meningismus, nausea, vomiting, and myelosuppression. The median peak Ara-C level in CSF was 16.69+/-6.30 mM (SD). The half life for elimination was 1.45+/-0.61 h (SD) There was no drug accumulation between courses. Neuropsychological evaluations were completed in eight patients, six (75%) of whom had preexisting cognitive deficits. Their condition generally improved over the course of treatment until the LMM progressed. No neurotoxic side effects of IVT Ara-C were observed in the two patients who had normal baseline cognitive assessments. CONCLUSIONS: IVT Ara-C at this dose and schedule has minimal activity as initial treatment for LMM from breast cancer despite achievement of high peak levels of the drug in the cerebrospinal fluid. A liposomal Ara-C formulation is currently under investigation.

Locally advanced breast cancer.

The multidisciplinary management of patients with locally advanced breast cancer (LABC) has evolved over the last three decades. The introduction of chemotherapy (CT) and endocrine therapy in conjunction with surgery and radiation therapy (XRT) have changed the natural history of this disease. The authors discuss the role of the taxanes, novel endocrine therapy, and high-dose CT programs in the management of LABC. Indications for breast-conserving surgery are presented. The role of prognostic and predictive tumor markers in LABC is discussed.