Optimizing the management of HER2-positive early breast cancer: the clinical reality

Breast cancer positive for HER2 (human epidermal growth factor receptor 2) is associated with a poor prognosis for patients with both early-stage and metastatic breast cancer. Trastuzumab has been shown to be effective and is now considered the standard of care for early-stage patients with HER2-positive breast cancer. In that population, trastuzumab has been studied in six randomized clinical trials. Overall, use of this agent leads to a significant reduction in risk of disease recurrence and improvement in overall survival. Despite the strong evidence for the use of trastuzumab in managing HER2-positive early breast cancer (EBC), a number of clinical controversies remain. The authors of this paper undertook a review of the available scientific literature on adjuvant trastuzumab to produce practical considerations from Canadian oncologists. The panel focused their discussion on five key areas: Management of node-negative disease with tumours 1 cm or smaller in size. Management of HER2-positive EBC across the spectrum of the disease (that is, nodal and steroid hormone receptor status, tumour size) Timing of trastuzumab therapy with chemotherapy for early-stage disease: concurrent or sequential. Treatment duration of trastuzumab for EBC. The role of non-anthracycline trastuzumab-based regimens.

Population-based study of wake-up strokes

OBJECTIVE

Previous studies have estimated that wake-up strokes comprise 8%to 28% of all ischemic strokes, but these studies were either small or not population-based. We sought to establish the proportion and event rate of wake-up strokes in a large population-based study and to compare patients who awoke with stroke symptoms with those who were awake at time of onset.

METHODS

First-time and recurrent ischemic strokes among residents of the Greater Cincinnati/Northern Kentucky region (population 1.3 million) in 2005 were identified using International Classification of Diseases-9 codes 430-436 and verified via study physician review. Ischemic strokes in patients aged 18 years and older presenting to an emergency department were included. Baseline characteristics were ascertained, along with discharge modified Rankin Scale scores and 90-day mortality.

RESULTS

We identified 1,854 ischemic strokes presenting to an emergency department, of which 273 (14.3%) were wake-up strokes. There were no differences between wake-up strokes and all other strokes with regard to clinical features or outcomes except for minor differences in age and baseline retrospective NIH Stroke Scale score. The adjusted wake-up stroke event rate was 26.0/100,000. Of the wake-up strokes, at least 98 (35.9%) would have been eligible for thrombolysis if arrival time were not a factor.

CONCLUSIONS

Within our population, approximately 14% of ischemic strokes presenting to an emergency department were wake-up strokes. Wake-up strokes cannot be distinguished from other strokes by clinical features or outcome. We estimate that approximately 58,000 patients with wake-up strokes presented to an emergency department in the United States in 2005.

Canadian Initiatives for Locally Advanced Breast Cancer Research and Treatment: Inaugural Meeting of the Canadian Consortium for LABC

The inaugural Canadian Consortium for LABC (locally advanced breast cancer) conference was held at Langdon Hall, Cambridge, Ontario, April 11–12, 2010. The meeting focused on current and future directions in labc treatment and research, the specific benefits of labc as a model for clinical and translational research, strategies for increased national and international collaboration, and ongoing clinical trials. Exciting Canadian initiatives in labc research are underway, focusing on identifying molecular signatures that will allow for the development of new tailored therapies. The challenge of identifying patient subgroups for accrual is being addressed through strategies to foster and improve national collaboration. This meeting report includes highlights from each presentation at the conference.

The role of HER2-targeted therapies in women with HER2-overexpressing metastatic breast cancer

The role of targeted therapies in the treatment of women with breast cancer has been rapidly evolving. Trastuzumab, a monoclonal antibody against the human epidermal growth factor receptor 2 (HER2), was the first HER2-targeted therapy that clearly demonstrated a significant clinical benefit for women with HER2-overexpressing metastatic breast cancer (mbc). However, in recent years it has become increasingly apparent that, when trastuzumab is used in the first-line setting in combination with chemotherapy, most women eventually develop progressive disease. Determining the treatment options available to women who have progressed while on trastuzumab therapy has been hampered by a paucity of high-quality published data. In addition, with the standard use of trastuzumab in the adjuvant setting (for eligible HER2-positive patients), the role of anti-HER2 agents for patients who experience a breast cancer relapse has become a clinically relevant question. This manuscript reviews current available data and outlines suggestions from a panel of Canadian oncologists about the use of trastuzumab and other HER2-targeted agents in two key mbc indications:Treatment for women with HER2-positive mbc progressing on trastuzumab (that is, treatment beyond progression)Treatment for women with HER2-positive mbc recurring following adjuvant trastuzumab (that is, re-treatment)The suggestions set out here will continue to evolve as data and future trials with trastuzumab and other HER2-targeted agents emerge.

BCIRG 007: Serum HER2 levels in women with metastatic HER2-amplified breast cancer

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Background: BCIRG 007 is a multicenter, phase 3 randomized trial comparing docetaxel and trastuzumab (TH) with docetaxel, platinum salt (cisplatin or carboplatin) and trastuzumab (TCH) as first line chemotherapy in women with metastatic breast cancer (MBC). Women enrolled in the study had to have primary breast tumors with HER2 amplification as determined by centralized FISH analysis. Methods: We determined the percentage of subjects with HER2 amplification who had elevated (>15ng/mL) baseline levels of serum HER2 prior to the initiation of trastuzumab-based therapies. Baseline was considered to be the last available determination within 21 days prior to first treatment. Results: The median baseline serum HER2 levels was 75.8 ng/mL (range=8–3,280 ng/mL) for all subjects (n=123), with no statistical difference between subjects randomized to receive TH (median=65.9 ng/mL, n=64) and those randomized to receive TCH (median=89.9 ng/mL, n=59). Overall, 89% of the 123 subjects with HER2-amplified primary tumors had serum HER2 levels >15 ng/mL at the time of metastatic disease (86% in TH vs 92% in TCH). Conclusions: There was no statistical impact of baseline serum HER2 levels on any important clinical event: response to treatment, clinical benefit (response or stable disease for more than 24 weeks), disease progression or death. Conversely, when serum HER2 was measured over time, subjects with higher levels had an elevated risk of experiencing progressive disease (p=.003), even after adjustment for extent of disease (1 or 2 vs 3 or more organs involved) and presence of visceral disease. These analyses suggest that monitoring serum HER2 levels over the course of disease may be a means for detecting progressive disease in women with HER2 amplified breast cancer. Given the long intervals between the serum HER2 measurement and progression (up to 9 months), caution is required in interpreting these results.

No significant financial relationships to disclose.

Class III beta tubulin expression and benefit from adjuvant cisplatin/vinorelbine chemotherapy in operable non-small cell lung cancer: Analysis of the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) study JBR.10

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Background: Biomarkers may be useful to select patients who will benefit from a particular chemotherapy regimen. High class III beta tubulin (bTubIII) expression in advanced NSCLC is known to correlate with reduced response rates and inferior survival with the anti-microtubule agents vinorelbine or paclitaxel. JBR.10 demonstrated a 12% and 15% improvement in 5-year recurrence-free (RFS) and overall survival (OS) respectively with the addition of cisplatin and vinorelbine following resection of stage IB-II NSCLC. We sought to determine the impact of bTubIII on patient outcome and benefit from adjuvant chemotherapy in the JBR.10 trial. Methods: We performed an immunohistochemical assay for bTubIII on primary tumor tissue available from 265 of the 482 patients in JBR.10. A validated, numerical bTubIII score was assigned by two observers based on the intensity and frequency of tumour cell staining. Tumours were classified as bTubIII “low” or “high” based on the median score. We examined the prognostic impact of bTubIII in patients treated with or without chemotherapy, and the survival benefit from chemotherapy in low versus high bTubIII subgroups. Results: High bTubIII expression was associated with poorer RFS (HR = 1.9, p = 0.01) in patients treated with surgery alone, but not in patients treated with adjuvant chemotherapy (HR = 1.1, p = .75). In the low bTubIII subgroup, the improvement in RFS with chemotherapy was non-significant (HR = 0.78, p = 0.4), while the improvement in RFS with chemotherapy was significant in the high bTubIII subgroup (HR = 0.45, p = 0.002). With Cox regression, the interaction between bTubIII status and chemotherapy treatment in predicting RFS did not reach statistical significance (p = 0.15). Results for OS were similar. Conclusions: Chemotherapy appeared to overcome the negative prognostic impact of high bTubIII expression. Greater benefit from adjuvant chemotherapy was seen in patients with high bTubIII expression. This is contrary to what has been seen in the setting of advanced disease; possible reasons for this difference are being explored.

No significant financial relationships to disclose.

High expression of nucleoside transporter hENT1 predicts a worse event-free survival in relapsed/refractory Hodgkin lymphoma patients treated with gemcitabine, vinorelbine, and liposomal doxorubicin—A CALGB 59804 correlative study

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Background: CALGB 59804 was a phase I/II trial of gemcitabine, vinorelbine, and liposomal doxorubicin (GVD) for pts with relapsed Hodgkin lymphoma (HL). Overall response rate (RR) was 70% (manuscript in review). Plasma membrane nucleoside transporters such as hENT1 are important in transporting nucleoside analogs into cells to exert their pharmacologic effects. We hypothesized high hENT1 expression would predict better RR and outcome in pts treated with GVD. Methods: 58 of 91 pts enrolled in CALGB 59804 had sufficient tissue for study; 31 relapse biopsies and 27 initial diagnosis biopsies. Expression of hENT1 was evaluated by immunohistochemistry in formalin fixed tissue and scored independently by two hematopathologists (RL and EH) blinded to the clinical outcomes. Positivity for hENT1 was defined as >25% of Reed-Sternberg (RS) cells expressing hENT1. Expression was correlated with clinical factors, including IPS at relapse, as well as the overall (OS) and event-free survival (EFS). Results: Expression of hENT1 in RS cells was heterogeneous among cases. 28/58 cases (48%) were hENT1-positive. hENT1-expression was not associated with age, gender, stage, IPS (≤2 or >2), or maximum toxicity grade (≤2 or >2). Compared to hENT1-negative pts, hENT1-positive pts were less likely to have complete or partial response (19/30, 63% versus 22/28, 76%, P=0.20, chi square). hENT1 expression was not significantly associated with OS (P=0.18). Univariate log-rank analysis showed hENT1 positivity and IPS >2 correlated significantly with a lower EFS (P=0.05, and P=0.03, respectively). Multivariate Cox regression analysis confirmed that IPS >2 and hENT1 positivity were independent predictors of EFS (Hazard ratio 2.16, 95%CI 1.08–4.35, P=0.03; and Hazard ratio 2.10, 95% CI 1.06–4.19, P=0.03, respectively). P-values are two-sided. Conclusions: Contrary to our hypothesis, there is an inverse relationship between EFS and hENT1 expression in relapsed HL pts treated with GVD. High expression of hENT1 did not identify gemcitabine-sensitive disease, but may identify a biologically aggressive and/or treatment refractory subtype of HL.

No significant financial relationships to disclose.

Prognostic significance of HER-2/neu over-expression on the incidence of brain metastasis in newly diagnosed breast cancer

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Background: As systemic therapy improves, brain metastases (BM) from breast cancer are becoming increasingly evident. An increased risk of BM in HER-2/neu over-expressing metastatic breast cancer patients has been suggested. However, the relationship between HER-2/neu over-expression and the risk of BM in newly diagnosed breast cancer patients is unknown. Methods: To determine incidence of BM in HER-2/neu over-expressing breast cancer patients, a cohort of patients between 01/1998 and 12/2003 with uniform HER-2/neu testing were identified from a cancer registry. A total of 460 patients with HER-2/neu over-expression and 500 patients with HER-2/neu negative disease were reviewed. Patients were excluded if there was breast cancer diagnosed before 01/1998 or others cancer. A total of 301 HER-2/neu over-expressing and 363 HER-2/neu negative patients were included for this analysis. The association between histological features and the occurrence of BM were evaluated with univariate and multivariate analyses. Results: BM were identified in 8% (24 patients) of HER-2/neu over-expressing breast cancer patients compared to only 1.7% (6 patients) in the HER-2/neu negative patients (hazard ratio 5.15 [2.079–12.78], p=0.0001). In patients with recurrent disease, the proportion of BM for HER-2/neu over-expressing patients was 24% compared to 10% in HER-2/neu negative patients. HER-2/neu over-expression, tumor size >2cm, ≥ 4 nodes positive and grade 2/3 were predictors of BM in univariate analysis. In multivariate analysis, HER-2/neu over-expression and tumor size>2cm were an independent prognostic factors for the development of BM, while hormone receptors expressions was protective (p=0.02). Conclusions: Our population based study show that newly diagnosed HER-2/neu over-expressing breast cancer patients are at significantly increased risk for BM. As most BM occur in HER-2/neu over-expressing patients with systemic metastatic disease, these findings could prompt consideration of brain prophylaxis strategies and/or serial radiologic screening to detect asymptomatic BM.

No significant financial relationships to disclose.

ER+ PR- breast cancer defines a unique subtype of breast cancer that is driven by growth factor signaling and may be more likely to respond to EGFR targeted therapies

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Background: Hormonal based therapy has long been the mainstay for treatment of ER+ breast cancer. ER+ PR- disease is now known to exhibit different clinical behavior compared to ER+PR+ disease. Recent data indicate that ER+PR- disease is characterized by a lower response rate to estrogen deprivation, has a worse prognosis compared to ER+ PR+ disease, and may be dependent on other signaling pathways. To evaluate the role of the EGFR tyrosine kinase inhibitor gefitnib in the treatment of breast cancer, we conducted a pre-surgical study in women with operable disease. Methods: Frozen core biopsies were obtained at baseline. Patients then received a short-term exposure to gefitinib (at least 2 weeks) prior to definitive surgery when a frozen tumor specimen was obtained. Tissue integrity and composition was verified by H and E and RNA was isolated for microarray analysis. 59 women were enrolled in the study of which 43 were evaluable for molecular analysis. Baseline microarrays were performed on the initial biopsies to classify the ‘subtype‘ of breast cancer (e.g. basal, luminal, HER2 amplified). To analyze the genetic changes that occur in breast cancer tissue with exposure to gefitinib, a direct comparison of the baseline sample and post-treatment tumor was performed. In addition, ER and PR status were determined by immunohistochemistry and compared to the microarray findings. Changes in Ki67 and a set of cell cycle genes were used to define ‘molecular response” to gefitinib. Of the 43 samples evaluated by microarray, 11 patients were categorized as exhibiting molecular growth inhibition, 10 patients as molecular growth proliferation, and 22 did not have a significant change in Ki67 and the cell cycle gene set to assign a response. When grouped by subtype, ER+PR- and HER2 amplified tumors define a subgroup more likely to show molecular growth inhibition with gefitinib. Conversely, ER+PR+ tumors were more likely to show molecular growth proliferation. Conclusions: These results support the hypothesis that ER+PR- breast cancer is growth factor dependent and constitutes a unique subgroup of ER+ patients which may be more likely to benefit from EGFR inhibition.

[Table: see text]

High-dose mitoxantrone–vinblastine–cyclophosphamide and autologous stem cell transplantation for stage III breast cancer: final results of a prospective multicentre study

BACKGROUND

Stage III breast cancer patients continue to suffer high relapse and death rates despite standard chemotherapy regimens. High-dose alkylator chemotherapy does not further improve outcome. This phase II study evaluated a novel high-dose chemotherapy regimen which combined active breast cancer agents with differing mechanisms of action.

PATIENTS AND METHODS

Eligibility included at least seven involved axillary nodes (AxLNs) for tumours <5 cm, at least four AxLNs for tumours >5 cm or locally advanced breast cancer (LABC). Patients received four cycles of fluorouracil-adriamycin-cyclophosphamide (FAC) followed by one cycle of mitoxantrone 63 mg/m(2)-vinblastine 12.5 mg/m(2)-cyclophosphamide 6 g/m(2) (MVC) with autologous blood stem cell transplantation (ASCT).

RESULTS

Between April 1995 and December 1998, 92 patients aged 21-65 years (median 45 years) were enrolled, of whom 25 were treated preoperatively for LABC and 67 were treated postoperatively. Although there was no early treatment-related mortality, one late death occurred from secondary acute myeloid leukaemia. The 7-year event-free and overall survival rates were 53% (95% confidence interval 42-64%) and 62% (95% CI 52-73%), respectively, with no significant difference between pre- and postoperative groups.

CONCLUSION

FAC followed by MVC-ASCT is feasible and reasonably well tolerated, but does not result in improved survival rates compared with other conventional or high-dose regimens for stage III breast cancer.

Whole genomewide linkage screen for neural tube defects reveals regions of interest on chromosomes 7 and 10

Neural tube defects (NTDs) are the second most common birth defects (1 in 1000 live births) in the world. Periconceptional maternal folate supplementation reduces NTD risk by 50-70%; however, studies of folate related and other developmental genes in humans have failed to definitively identify a major causal gene for NTD. The aetiology of NTDs remains unknown and both genetic and environmental factors are implicated. We present findings from a microsatellite based screen of 44 multiplex pedigrees ascertained through the NTD Collaborative Group. For the linkage analysis, we defined our phenotype narrowly by considering individuals with a lumbosacral level myelomeningocele as affected, then we expanded the phenotype to include all types of NTDs. Two point parametric analyses were performed using VITESSE and HOMOG. Multipoint parametric and nonparametric analyses were performed using ALLEGRO. Initial results identified chromosomes 7 and 10, both with maximum parametric multipoint lod scores (Mlod) >2.0. Chromosome 7 produced the highest score in the 24 cM interval between D7S3056 and D7S3051 (parametric Mlod 2.45; nonparametric Mlod 1.89). Further investigation demonstrated that results on chromosome 7 were being primarily driven by a single large pedigree (parametric Mlod 2.40). When this family was removed from analysis, chromosome 10 was the most interesting region, with a peak Mlod of 2.25 at D10S1731. Based on mouse human synteny, two candidate genes (Meox2, Twist1) were identified on chromosome 7. A review of public databases revealed three biologically plausible candidates (FGFR2, GFRA1, Pax2) on chromosome 10. The results from this screen provide valuable positional data for prioritisation of candidate gene assessment in future studies of NTDs.

Dose rate calculations for a reconnaissance vehicle

A Chemical Nuclear Reconnaissance System (CNRS) has been developed by the British Ministry of Defence to make chemical and radiation measurements on contaminated terrain using appropriate sensors and recording equipment installed in a land rover. A research programme is under way to develop and validate a predictive capability to calculate the build-up of contamination on the vehicle, radiation detector performance and dose rates to the occupants of the vehicle. This paper describes the geometric model of the vehicle and the methodology used for calculations of detector response. Calculated dose rates obtained using the MCBEND Monte Carlo radiation transport computer code in adjoint mode are presented. These address the transient response of the detectors as the vehicle passes through a contaminated area. Calculated dose rates were found to agree with the measured data to be within the experimental uncertainties, thus giving confidence in the shielding model of the vehicle and its application to other scenarios.

Darbepoetin alfa administered every 3 weeks alleviates anaemia in patients with solid tumours receiving chemotherapy; results of a double-blind, placebo-controlled, randomised study

This dose-finding, placebo-controlled study evaluated the safety and efficacy of darbepoetin alfa administered every 3 weeks (Q3W) to anaemic patients receiving chemotherapy. In part A, patients (haemoglobin </=110 g/l) were randomised in a 1:4 ratio to receive 1 of 6 doses of darbepoetin alfa (4.5, 6.75, 9.0, 12.0, 13.5 and 15.0 microg/kg) or placebo Q3W for 12 weeks. In part B, patients received open-label darbepoetin alfa. Patients (n=249) were evaluated for safety, haemoglobin endpoints and red blood cell (RBC) transfusions. Darbepoetin alfa given at doses ranging from 4.5 to 15.0 microg/kg Q3W was well tolerated and comparable to placebo in terms of safety. No neutralising antibodies were detected. All doses (from 4.5 to 15 microg/kg) reduced transfusions compared with placebo, and resulted in >50% of patients achieving a haematopoietic response. Administration of darbepoetin alfa Q3W has a tolerable safety profile and effectively ameliorates anaemia due to chemotherapy.

Plasma and neutrophil fatty acid composition in advanced cancer patients and response to fish oil supplementation

Metabolic demand and altered supply of essential nutrients is poorly characterised in patients with advanced cancer. A possible imbalance or deficiency of essential fatty acids is suggested by reported beneficial effects of fish oil supplementation. To assess fatty acid status (composition of plasma and neutrophil phospholipids) in advanced cancer patients before and after 14 days of supplementation (12+/-1 g day(-1)) with fish (eicosapentaenoic acid, and docosahexaenoic acid) or placebo (olive) oil. Blood was drawn from cancer patients experiencing weight loss of >5% body weight (n=23). Fatty acid composition of plasma phospholipids and the major phospholipid classes of isolated neutrophils were determined using gas liquid chromatography. At baseline, patients with advanced cancer exhibited low levels (<30% of normal values) of plasma phospholipids and constituent fatty acids and elevated 20 : 4 n-6 content in neutrophil phospholipids. High n-6/n-3 fatty acid ratios in neutrophil and plasma phospholipids were inversely related to body mass index. Fish oil supplementation raised eicosapentaenoic acid and docosahexaenoic acid content in plasma but not neutrophil phospholipids. 20 : 4 n-6 content was reduced in neutrophil PI following supplementation with fish oil. Change in body weight during the supplementation period related directly to increases in eicosapentaenoic acid in plasma. Advanced cancer patients have alterations in lipid metabolism potentially due to nutritional status and/or chemotherapy. Potential obstacles in fatty acid utilisation must be addressed in future trials aiming to improve outcomes using nutritional intervention with fish oils.

Selective cytotoxicity of gemcitabine in bladder cancer cell lines

We have examined the cytotoxic effect of gemcitabine in intravesical therapy using an in vitro co-cultured spheroid model composed of transitional cell carcinoma (TCC) and fibroblasts from both human and rat species. Immunohistochemistry analysis of the co-cultured spheroids, using cytokeratin-13 and vimentin antibodies against TCC and fibroblasts, respectively, showed the central location of fibroblasts within the spheroid, whereas TCC formed the peripheral layers. Spheroids composed of human TCC and fibroblasts (MGH-U3/CRL-1120 or RT-112/CRL-1120) as well as rat TCC and their corresponding fibroblasts (AY-27/RF-Ed1) displayed the same drug tolerance profile after an exposure of 0, 1, 3, 5, 7 and 14 days. As confirmed by time-lapse photography, MTT essay and vital dye staining, gemcitabine selectively killed the human and rat bladder cancer cell lines, but did not affect un-transformed human and rat fibroblast lines.

Resistance to Scald (Rhynchosporium secalis) in Barley (Hordeum vulgare) Studied by Near-Isogenic Lines: I. Markers and Differential Isolates

ABSTRACT Near-isogenic lines (NILs) with resistance for scald in seventh generation backcross with 'Ingrid' as recurrent parent (RP) were tested with seven differential isolates of Rhynchosporium secalis in Norway and Canada. NILs of 'Turk', 'Brier', 'CI 8162', 'La Mesita', 'Hispont', 'Atlas 46', 'Modoc', 'Hudson', 'Abyssinian', 'Steudelli', and 'CI 2222' also were evaluated for field reactions. The genetic characterization of the NILs (degree of isogeneity with Ingrid) and with each other was carried out. The molecular marker pattern shows that the backcrossing program has resulted in from 86.3 to 100% RP genome in the NILs, depending on the marker system. On an average, 96% RP genome was found in the NILs. There were certain consistent (pairwise) differences between the NILs and RP on chromosomes 3H and 7H. Both chromosomes are known to contain loci conferring resistance to R. secalis, indicating successful introgression from the donors into the NILs. Approximately two-thirds of the observed RP-NIL polymorphisms were linked to the assumed resistance in the NIL. Based on the marker and phenotypic analyses of the NILs, suggestions for a more appropriate and updated terminology of genes for resistance to R. secalis in barley are made. The proposed changes in nomenclature also indicate the differentials that are available as NILs and those lacking.

Zoledronic acid versus pamidronate in the treatment of skeletal metastases in patients with breast cancer or osteolytic lesions of multiple myeloma: a phase III, double-blind, comparative trial

PURPOSE

Zoledronic acid, a new and more potent bisphosphonate, was compared with pamidronate, the current standard treatment for patients with osteolytic or mixed bone metastases/lesions.

PATIENTS AND METHODS

A total of 1,648 patients with either Durie-Salmon stage III multiple myeloma or advanced breast cancer and at least one bone lesion were randomly assigned to treatment with either 4 or 8 mg of zoledronic acid via 15-minute intravenous infusion or 90 mg of pamidronate via 2-hour intravenous infusion every 3 to 4 weeks for 12 months. The primary efficacy endpoint was the proportion of patients experiencing at least one skeletal-related event over 13 months.

RESULTS

The proportion of patients with at least one skeletal-related event was similar in all treatment groups. Median time to the first skeletal-related eventwas approximately 1 year in each treatment group. The skeletal morbidity rate was slightly lower in patients treated with zoledronic acid than in those treated with pamidronate, and zoledronic acid (4 mg) significantly decreased the incidence and event rate for radiation therapy to bone, both overall and in breast cancer patients receiving hormonal therapy. Pain scores decreased in all treatment groups in the presence of stable or decreased analgesic use. Zoledronic acid (4 mg) and pamidronate were equally well tolerated; the most common adverse events were bone pain, nausea, fatigue, and fever and < 5% of serious adverse events were related to the study drug. The incidence of renal impairment among patients treated with 4 mg of zoledronic acid via 15-minute infusion was similar to that among patients treated with pamidronate.

CONCLUSIONS

Zoledronic acid (4 mg) via 15-minute intravenous infusion was as effective and well tolerated as 90 mg of pamidronate in the treatment of osteolytic and mixed bone metastases/lesions in patients with advanced breast cancer or multiple myeloma. (Can-

Frequency of celiac disease in individuals with Down syndrome in the United States

Ninety-three individuals with Down syndrome (DS) were screened to investigate the prevalence of celiac disease (CD) in the United States. Five of the 93 individuals were antiendomysial antibody (EMA) positive. Of the 5 who tested positive for EMA, 4 were biopsied, 1 refused biopsy. Three of the 4 individuals biopsied manifested changes of CD on small bowel biopsy. This gives a frequency of 3.2% of confirmed CD in our DS individuals and suggests the need for periodic screening for celiac disease in this population.