Single-agent lapatinib for HER2-overexpressing advanced or metastatic breast cancer that progressed on first- or second-line trastuzumab-containing regimens

BACKGROUND

This phase II study evaluated the efficacy and safety of lapatinib in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer that progressed during prior trastuzumab therapy.

PATIENTS AND METHODS

Women with stage IIIB/IV HER2-overexpressing breast cancer were treated with single-agent lapatinib 1250 or 1500 mg once daily after protocol amendment. Tumor response according to RECIST was assessed every 8 weeks. HER2 expression was assessed in tumor tissue by immunohistochemistry and FISH.

RESULTS

Seventy-eight patients were enrolled in the study. Investigator and independent review response rates [complete response (CR) or partial response (PR)] were 7.7% and 5.1%, and clinical benefit rates (CR, PR, or stable disease for >or=24 weeks) were 14.1% and 9.0%, respectively. Median time to progression was 15.3 weeks by independent review, and median overall survival was 79 weeks. The most common treatment-related adverse events were rash (47%), diarrhea (46%), nausea (31%), and fatigue (18%).

CONCLUSIONS

Single-agent lapatinib has clinical activity with manageable toxic effects in HER2-overexpressing breast cancer that progressed on trastuzumab-containing therapy. Studies of lapatinib-based combination regimens with chemotherapy and other targeted therapies in metastatic and earlier stages of breast cancer are warranted.

A multi-center phase II study of three doses of TAS-108 in postmenopausal women with advanced breast carcinoma following first or second line endocrine therapy

Abstract #2131

Introduction: TAS-108 is an oral steroidal anti-estrogen agent that selectively inhibits ERα and is mainly metabolized by CYP3A4. The purpose of this study is to investigate the efficacy and safety of TAS-108 administrated orally in three dose levels in patients with locally advanced, locally recurrent inoperable or metastatic breast carcinoma (BC) in four countries (USA, Russia, Mexico and Chile).
 Methods: Postmenopausal women with confirmed ER and/or PgR positive BC who had previously responded to one or two standard endocrine therapies, with or without one prior chemotherapy were randomly assigned to three doses of TAS-108, 40 mg, 80 and 120 mg daily. Using a modified Panageas' optimal two-stage trinomial design, the enrollment of 60 evaluable patients (first-stage: 19) was required to each individual dose group. Tumor response was assessed every 8 weeks according to RECIST criteria. Adverse events (AEs) were graded by CTC-AE v3.0.
 Results: A total of 146 patients with mean age of 63 years old were enrolled with 61 patients in the 40 mg group and 66 in the 80 mg group. The 120 mg group was terminated at the end of stage 1 with 19 patients enrolled due to lack of efficacy. The mean duration of study treatment was 172 days for the 40 mg group and 160 days for the 80 mg group. Partial response (PR) was documented in 6 (10%) patients in the 40 mg group and 4 (6.7%) patients in the 80 mg group. The rate of disease stabilization (CR+PR+SD) reported by the investigators was 43% (95%CI, 31%,56%) in the 40 mg group and 45% (95%CI, 32%,58%) in the 80 mg group. Adjudicated clinical benefit (CR+PR+SD more than 24 wks) was observed in 22% of patients in the 40 mg group and 20% of patients in the 80 mg group. Clinical benefit was achieved in 25% of patients with 1 prior hormonal therapy and 15% of patients with more than one line of prior hormonal therapy. Median time to progression (TTP): 15 weeks for the 40 mg group and 15.9 weeks for the 80 mg group. Median duration of clinical benefit was 32 weeks in the 40 mg group and 64 weeks in the 80 mg group. In the 40/80/120 mg groups, the commonly reported treatment-related AEs included nausea (15%/11%/16%), fatigue (10%/11%/16%), headache (10%/6%/16%), hot flushes (10%/5%/32%), diarrhea (2%/6%/5%), constipation (3%/3%/5%), and arthralgia (2%/5%/11%). No endometrial cancer and treatment-related deaths occurred during the study.
 Conclusions: TAS-108 has demonstrated anti-tumor activity in this population and was generally well tolerated. The 40 mg dose was chosen as the recommended dose for future clinical evaluation in patients with advanced breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2131.

Survival of patients with HER2+ metastatic breast cancer and use of trastuzumab following progression: analysis of RegistHER

Abstract #3142

Background: Most HER2+ metastatic breast cancer (MBC) patients who initially respond to trastuzumab (T)-based therapies will experience disease progression (PD). Standard practice is to discontinue the cytotoxic agent on which disease progressed, however there is evidence that tumors may remain sensitive to HER2 targeting and that there may be a potentiating effect of T on chemotherapy. We examined the treatment history of a large population of HER2+ MBC patients to assess outcomes associated with continuation of T beyond PD.
 Methods: This analysis was carried out on patients enrolled in registHER, a prospective observational study of 1023 patients with newly diagnosed (within 6 months) HER2+ MBC. Median f/u from MBC diagnosis is 25 months at the time of data cut-off (12/31/07). For those treated with T prior to first PD, we compared demographics and baseline tumor characteristics for those patients treated with or without T following first PD. Treatment with T was defined as a minimum of 21 days of therapy prior to PD. In addition, we evaluated time to second PD, and overall survival post PD (both endpoints calculated from initial PD). Overall survival (OS) was also calculated from the date of treatment initiation to death for the entire treated cohort.
 Results: Of 1023 evaluable patients, 873 (85%) were treated with any T-based first-line therapy. 622 T-treated patients progressed and 500 were subsequently treated with T following first PD. Patients who received T post first PD tended to be younger (<50 years of age, 45.2% vs 29.5%) and have hormone receptor positive disease (51.4% vs 42.0%) compared with patients who did not receive T post first PD. Among all treated patients the median overall survival was 35.6 mo (25th-75th-ile:18.6-63.1 mo). Median survival post PD in the 500 patients treated with trastuzumab following first PD was 21.2 mo (25th-75th-ile:11.8-35.8mo).
 Conclusions: OS in patients on the prospective observational study registHER is longer than the OS of 25.1 months noted in the pivotal trial of first-line HER2+ MBC patients treated with T plus chemotherapy. We will present data on the association between various pre- and post-treatment factors, including the use of T beyond PD, and PFS and OS. This will include a multivariate analysis that specifically examines the association between T use in later lines and survival.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3142.

registHER: Patient characteristics, treatment patterns, and preliminary outcomes in patients with HER2-positive (HER2+), hormone receptor-positive (HR+) metastatic breast cancer (MBC)

21007

Background: Approximately 50% of HER2+ breast cancers are HR+, however, the interaction between HER2 and HR is not completely understood. Patients with HR+/HER2+ or HR-/HER2+ tumors treated with trastuzumab + chemotherapy (CT) achieve similar clinical benefit. Retrospective analyses suggest that HER2+ tumors are resistant to hormone therapy (HT), particularly anti-estrogens, possibly due to estrogen receptor /HER2 interactions and quantitatively lower HR expression in HER2+/HR+ tumors. Conducting randomized clinical trials in HER2+/HR+ MBC is challenging given the small patient population. Methods: registHER is a prospective observational study of approximately 1000 patients with newly diagnosed (<6 months) HER2+ MBC treated in community or academic settings. Baseline characteristics and treatment patterns in patients with HR+ vs HR-, HER2+ MBC receiving first-line therapy were studied in this analysis. The influence of adjuvant HT on disease-free intervals (DFI) from time of diagnosis and MBC treatment selection in patients with HR+/HER2+ tumors was examined. Results: Of 976 patients with HER2+ MBC and recorded tumor HR status, those with HR+ MBC (54.9%) tended to be white (81.7% vs 77.0%), were more likely to have bone only metastases (18.1% vs 6.4%), less likely to have CNS metastases (2.8% vs 8.2%), and have fewer metastatic sites at diagnosis (49.1% vs 43.2%) than those with HR- MBC. Of patients with HR+ MBC, who were stage I- III at initial diagnosis, 51.3% received adjuvant HT, of which 73.2% received tamoxifen. Median DFI was 48.8 vs 29.4 mo for patients receiving tamoxifen vs an aromatase inhibitor. First-line MBC treatment regimens included: HT only (13.8%); HT + trastuzumab (8.4%); HT + trastuzumab + CT (6.2%); trastuzumab only (6.0%); CT only (11.0%); trastuzumab + CT (53.5%). Analyses of progression-free survival by HR status and first-line treatments (HT only, trastuzumab ± HT or ± CT), are ongoing and will be described. Conclusions: registHER represents the largest dataset of patients with HER2+/HR+ MBC and provides a unique opportunity to characterize treatment patterns, efficacy and safety, and the natural history of this subset of breast cancer patients.

[Table: see text]

Zoledronic Acid Inhibits Adjuvant Letrozole–Induced Bone Loss in Postmenopausal Women With Early Breast Cancer

Purpose

Treatment with aromatase inhibitors decreases bone mineral density (BMD) and may increase the risk of fractures in postmenopausal women with early-stage breast cancer. The addition of zoledronic acid to adjuvant letrozole therapy may protect against bone loss.

Patients and Methods

Patients receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months). The delayed group received zoledronic acid when lumbar spine (LS) or total hip (TH) T score decreased to less than −2.0 or when a nontraumatic fracture occurred. The primary end point of this study was to compare the change in LS BMD at month 12 between the groups. Secondary end points included change in TH BMD and changes in serum bone turnover markers at month 12.

Results

The upfront and delayed groups each included 301 patients. At month 12, LS BMD was 4.4% higher in the upfront group than in the delayed group (95% CI, 3.7% to 5.0%; P < .0001), and TH BMD was 3.3% higher (95% CI, 2.8% to 3.8%; P < .0001). In the upfront group, mean serum N-telopeptide and bone-specific alkaline phosphatase concentrations decreased by 15.1% (P < .0001) and 8.8% (P = .0006), respectively, at month 12, whereas concentrations increased significantly in the delayed group by 19.9% (P = .013) and 24.3% (P < .0001), respectively.

Conclusion

With 1 year of follow-up, results of the primary end point of the Zometa-Femara Adjuvant Synergy Trial (Z-FAST) indicate that upfront zoledronic acid therapy prevents bone loss in the LS in postmenopausal women receiving adjuvant letrozole for early-stage breast cancer.

Updated results of a multicenter phase II trial of neoadjuvant docetaxel, carboplatin and capecitabine for inflammatory and locally advanced breast cancer (LABC)

10685

Background: Neoadjuvant chemotherapy for the treatment of LABC has become the standard of care but the best combination is not established. The combination of docetaxel and capecitabine demonstrates synergism in patients(pts) with metastatic breast cancer (MBC). Recent studies support the value of platinum salts in LABC and MBC. Methods: pts with stage IIA-IIIC or inflammatory BC, EGOG PS 0–1, are eligible.We are evaluating the combination of weekly docetaxel 30mg/m2, carboplatin AUC2 on D1, 8,15 of a 4-week cycle plus capecitabine 625 mg/m2 BID given on days 5–18 (based on the upregulation of thymidine phosphorylase) for 4 cycles prior to surgery. The primary objective of this phase II trial is pCR rate in breast. Results: 39 of 48 pts have been enrolled from 7 centers. Median age 46 (range 26–75), stage II 41%, stage III 59%. Median baseline tumor is 5.4cm (range 2.1–15); 1pt inflammatory BC; 10 pts N2 disease (36%); 12 tumors were ER+, 20 ER-, and 5 Her-2+. To date, 2,377 doses (including daily capecitabine doses) were administered out of a total of 2,560 (93% of intended doses) with only 10 dose delays and 8 dose reductions. 37 pts are evaluable for toxicities. No grade IV toxicities were seen, grade III neutropenia was seen in 3/37(8%) and grade III fatigue in 1/37(3%). There were no episodes of neutropenic fever.The most common grade I/II toxicities were nausea in 57%, diarrhea 38%, fatigue 43%, epiphora 24%, mucositis 24% and hand-foot syndrome 3%. No death related treatments have been reported. 32 pts have completed definitive surgery. Objective clinical response is 94% with 53% cCR. 5 patients had pCRs in breast(16%) and 5 pCR in breast and axilla(16%). 9 pts (28%) have microscopic residual disease in the breast (<3mm). 14 pts had complete axillary clearance (44%). Conclusions: The preoperative combination of docetaxel, carboplatin and capecitabine is feasible with very good response rate and a very acceptable toxicity profile. Accrual is ongoing.

No significant financial relationships to disclose.

Phase II study of gemcitabine (Gem) and trastuzumab (T) combination therapy in first line metastatic breast cancer (MBC) patients (pts) with HER2 overexpression

10591

Background: Phase III studies have demonstrated that the addition of T to chemo is associated with higher response rates (RR), improved time-to-progression (TTP) and improved overall survival in pts with metastatic HER2+ tumors. The greatest benefit from T-based therapy is found in women with pronounced HER2 overexpression (FISH+ or IHC 3+). Preclinical models suggest that Gem+T appear to be additive or synergistic. The present study was designed to determine overall RR (primary endpoint), TTP, OS and the toxicity profile of the combination of Gem+T as first-line therapy for MBC pts. Methods: Pts with measurable HER2-overexpressing (IHC 3+ or FISH+) MBC, no prior chemo in the metastatic setting (adjuvant was allowed), adequate end-organ function and PS 0–2, received Gem 1,250 mg/m2 on days 1 and 8 and T on day 1 (8 mg/kg over 90 min on cycle 1, then 6 mg/kg over 30 min on subsequent cycles) of a 21-day cycle, until progressive disease or undue toxicity. A Simon’s optimal two-stage design was used with a total sample size of 66 (25 patients treated in the first stage and 41 additional patients in the second stage). Results: Sixty-six patients have been treated and results are available for sixty-four patients. Median age: 53 years (range 34–83); Race: Caucasian/Other 88%/12%. ER status positive/negative: 53%/47%. HER2 status IHC 3+/FISH+: 58/20 pts.; ECOG PS 0/1/2: 66%/30%/3%; Prior adjuvant therapy: Chemo 39 pts (prior anthra 31, prior taxane 21), Hormonal 32 pts (6 adj, 18 met, 8 both). Total number of cycles = 396; median = 6 (range 1–21). Toxicity was generally modest. Grade 3/4 neutropenia occurred in 11 pts (17%)/7 pts (11%); thrombocytopenia 3pts (5%)/1pt (2%), anemia 3 pts (4.7%)/ 0 pts, and 2 pts with grade 4 transaminase elevation, grade 3 elevated ALT 6 pts (9.4%); no other grade 4 toxicities were recorded. One pt with prior anthra exposure had a grade 2 decrease in left ventricular ejection fraction; no symptomatic cardiac toxicity was recorded. Best Overall RR assessment (N = 64): CR 8 (12.5%), PR 26 (40.6%) for an overall RR of 53.1% (95% CI: 40%-66%). TTP median 6 mo (95% CI: 4.4 -9.7 mo). Survival data not mature at this time. Conclusions: The combination of Gem+T in front-line MBC shows a high response rate with modest toxicity.

[Table: see text]

Capecitabine plus docetaxel (XT): A first line, phase II clinical trial in metastatic breast cancer

10624

Background: The XT combination originally published at (X) dosed at 1250 mg/m2 bid po x 14 days and (T) at 75 mg/m2 q3 weeks I.V. respectively yielded good response rates and an overall survival advantage compared with single agent docetaxel at 100 mg/m2. However, the toxicity profile of this regimen has led to major dose and schedule modifications by most oncologists. Methods/Results: We initiated a Phase II trial at doses of X at 900 mg/m2 bid po x 14 days and T at 36 mg/m2 d 1 and 8. Three responded and the mean no. of cycles for these patients was 3.8. Since four of 6 went off study because of toxicity two additional dose levels were studied in 6 patients each. A second cohort received X at 650 mg/m2 bid and T at 30 mg/m2. With 6 evaluable patients, four of 6 responded but all 4 required further dose reductions. Mean no. of cycles received was 4.2. A third cohort of 6 patients received X at 825 mg/m2 plus the lower T at 30mg/m2 who received a mean no. of cycles of 6. While only 1/6 responded 3 additional patients had stable disease with marked decreases in CEA or CA 15–3 suggestive of anti-tumor response. Only 1/6 required a dose reduction. Among the 18 patients, epiphora was described by 5 (28%). Only 3 patients developed significant leukopenia, and thrombocytopenia was not seen. T-induced nail changes were uncommon but were severe in one patient. Two patients at the first dose level, but only one at lower levels developed mucositis. Grade 1 anemia was common but managed easily with growth factor support. Conclusions: The response rate of 44% is encouraging with these lower doses of XT. We recommend further studies using X at 825 mg/m2 and T at 30mg/m2 since these doses were associated with encouraging response rate and a better toxicity profile than higher doses. Even at this higher dose of X dose reductions may well be needed. (Supported by a grant from Roche Laboratories, Inc.)

No significant financial relationships to disclose.

registHER: Baseline characteristics of a cohort of HER2-positive metastatic breast cancer (MBC) patients

20095

Background: HER2 is amplified in 25% of breast cancers and is associated with poor survival. registHER captures the natural history, treatment patterns and outcomes in 1000 newly-diagnosed HER2-positive MBC patients (pts) throughout the U.S. This observational study recruits pts in both academic and community centers. Methods: This ongoing prospective cohort study collects clinical, pathologic and treatment data at enrollment, quarterly until death, loss to follow-up or 3 years after the last enrollment. We describe baseline pt and clinical characteristics in registHER compared with HER2-positive MBC pts in the phase III pivotal trial (Slamon DJ, et al. N Engl J Med. 2001;344:783–792). Results: Between December 2003 and September 2005, 813 eligible pts were enrolled at 280 study sites. Most pts were seen at community-based (76%) vs academic (18%) clinics; a few pts did not fall into either category (6%). A comparison of baseline characteristics is shown below. Conclusions: registHER pts tended to have a shorter disease-free interval and more estrogen receptor positive disease than pts in the pivotal trial. Reasons for these differences could reflect trial referral and/or diagnostic testing differences. Fewer registHER patients were white, but other characteristics were similar between the two groups. These findings support the hypothesis that observational studies describe a broad patient population which may not exactly duplicate clinical trials. Within registHER, there was some variation between academic vs community clinics (eg. nodal status and adjuvant therapy). Treatment pattern analyses are ongoing.

[Table: see text]

[Table: see text]

Evaluation of a recombinant HER2 vaccine: Induction of specific antibodies, T-cells and preliminary activity in metastatic breast cancer patients

631

Background: We designed a vaccine to induce T cells able to recognize epitopes from HER2 and to engender a polyclonal antibody reponse. Methods: The vaccine is a recombinant HER2 protein, including its extra and part of its intra-cellular domains (ECD/ICD), combined with a potent immunologic adjuvant. Cohorts of patients with Stage II/III breast cancer (BC) received 20, 100 or 500 μg in the adjuvant setting. Treatment comprised of six vaccinations over 14 weeks, for the 500-μg dose, recall injections were given on weeks 34 and 38. The trial was extended to include an alternative vaccination schedule: 500 μg on days 0, 28 and 98. In an on-going trial, patients with metastatic BC treated in the first line setting are receiving the 500-μg treatment and being assessed for clinical response. Results: The vaccine was well tolerated, with no symptomatic cardiotoxicity. Antibody (Ab) response against ECD was dose-dependent, with 2/12, 9/14 and 14/15 immune responders in the respective cohorts after four vaccinations. Response was dose-related. Ab isotypes were analyzed in the 500 μg cohort: in 50% of patients, high levels of IgM (30–60%) against ECD were found after four vaccinations. The switch towards IgG was complete in all patients after six vaccinations. The efficacy of booster vaccinations was observed mainly in patients with low IgM after eight weeks. After two vaccinations, Ab titers on the alternative 500 μg vaccination schedule were as high as after four vaccinations utilizing the initial schedule. The anti-ECD antibodies in 11/15 patients (500 μg level) bound HER2-overexpressing breast-cancer cell lines. In sera from 2 patients tested thus far, the gene-expression resembled that of trastuzumab. Assays show that specific T cells were obtained; detailed analysis is continuing. Among metastatic patients, two showed evidence of tumor regression after vaccination. Conclusions: The HER2 vaccine was well tolerated and induced (dose-dependently) anti-ECD Ab that bound the HER2 receptor. Data suggest that the vaccine also induced specific T-cell immunity. The alternative vaccination schedule may increase the Ab titers. This data justifies further evaluation of this vaccine in the phase II/III setting.

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Prognosis after ipsilateral breast tumor recurrence and locoregional recurrences in five National Surgical Adjuvant Breast and Bowel Project node-positive adjuvant breast cancer trials

PURPOSE

Locoregional failure after breast-conserving surgery is associated with increased risk of distant disease and death. The magnitude of this risk in patients receiving chemotherapy has not been adequately characterized.

PATIENTS AND METHODS

Our study population included 2,669 women randomly assigned onto five National Surgical Adjuvant Breast and Bowel Project node-positive protocols (B-15, B-16, B-18, B-22, and B-25), who were treated with lumpectomy, whole-breast irradiation, and adjuvant systemic therapy. Cumulative incidences of ipsilateral breast tumor recurrence (IBTR) and other locoregional recurrence (oLRR) were calculated. Kaplan-Meier curves were used to estimate distant-disease-free survival (DDFS) and overall survival (OS) after IBTR or oLRR. Cox models were used to model survival using clinical and pathologic factors jointly with IBTR or oLRR as time-varying predictors.

RESULTS

Four hundred twenty-four patients (15.9%) experienced locoregional failure; 259 (9.7%) experienced IBTR, and 165 (6.2%) experienced oLRR. The 10-year cumulative incidence of IBTR and oLRR was 8.7% and 6.0%, respectively. Most locoregional failures occurred within 5 years (62.2% for IBTR and 80.6% for oLRR). Age, tumor size, and estrogen receptor status were significantly associated with IBTR. Nodal status and estrogen and progesterone receptor status were significantly associated with oLRR. The 5-year DDFS rates after IBTR and oLRR were 51.4% and 18.8%, respectively. The 5-year OS rates after IBTR and oLRR were 59.9% and 24.1%, respectively. Hazard ratios for mortality associated with IBTR and oLRR were 2.58 (95% CI, 2.11 to 3.15) and 5.85 (95% CI, 4.80 to 7.13), respectively.

CONCLUSION

Node-positive breast cancer patients who developed IBTR or oLRR had significantly poorer prognoses than patients who did not experience these events.

Assessment of cardiac dysfunction in a randomized trial comparing doxorubicin and cyclophosphamide followed by paclitaxel, with or without trastuzumab as adjuvant therapy in node-positive, human epidermal growth factor receptor 2-overexpressing breast cancer: NSABP B-31

PURPOSE

Trastuzumab is effective in treating human epidermal growth factor receptor 2 (HER2) -positive breast cancer, but it increases frequency of cardiac dysfunction (CD) when used with or after anthracyclines.

PATIENTS AND METHODS

National Surgical Adjuvant Breast and Bowel Project trial B-31 compared doxorubicin and cyclophosphamide (AC) followed by paclitaxel with AC followed by paclitaxel plus 52 weeks of trastuzumab beginning concurrently with paclitaxel in patients with node-positive, HER2-positive breast cancer. Initiation of trastuzumab required normal post-AC left ventricular ejection fraction (LVEF) on multiple-gated acquisition scan. If symptoms suggestive of congestive heart failure (CHF) developed, source documents were blindly reviewed by an independent panel of cardiologists to determine whether criteria were met for a cardiac event (CE), which was defined as New York Heart Association class III or IV CHF or possible/probable cardiac death. Frequencies of CEs were compared between arms.

RESULTS

Among patients with normal post-AC LVEF who began post-AC treatment, five of 814 control patients subsequently had confirmed CEs (four CHFs and one cardiac death) compared with 31 of 850 trastuzumab-treated patients (31 CHFs and no cardiac deaths). The difference in cumulative incidence at 3 years was 3.3% (4.1% for trastuzumab-treated patients minus 0.8% for control patients; 95% CI, 1.7% to 4.9%). Twenty-seven of the 31 patients in the trastuzumab arm have been followed for > or = 6 months after diagnosis of a CE; 26 were asymptomatic at last assessment, and 18 remained on cardiac medication. CHFs were more frequent in older patients and patients with marginal post-AC LVEF. Fourteen percent of patients discontinued trastuzumab because of asymptomatic decreases in LVEF; 4% discontinued trastuzumab because of symptomatic cardiotoxicity.

CONCLUSION

Administering trastuzumab with paclitaxel after AC increases incidence of CHF and lesser CD. Potential cardiotoxicity should be carefully considered when discussing benefits and risks of this therapy.

Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer

BACKGROUND

We present the combined results of two trials that compared adjuvant chemotherapy with or without concurrent trastuzumab in women with surgically removed HER2-positive breast cancer.

METHODS

The National Surgical Adjuvant Breast and Bowel Project trial B-31 compared doxorubicin and cyclophosphamide followed by paclitaxel every 3 weeks (group 1) with the same regimen plus 52 weeks of trastuzumab beginning with the first dose of paclitaxel (group 2). The North Central Cancer Treatment Group trial N9831 compared three regimens: doxorubicin and cyclophosphamide followed by weekly paclitaxel (group A), the same regimen followed by 52 weeks of trastuzumab after paclitaxel (group B), and the same regimen plus 52 weeks of trastuzumab initiated concomitantly with paclitaxel (group C). The studies were amended to include a joint analysis comparing groups 1 and A (the control group) with groups 2 and C (the trastuzumab group). Group B was excluded because trastuzumab was not given concurrently with paclitaxel.

RESULTS

By March 15, 2005, 394 events (recurrent, second primary cancer, or death before recurrence) had been reported, triggering the first scheduled interim analysis. Of these, 133 were in the trastuzumab group and 261 in the control group (hazard ratio, 0.48; P<0.0001). This result crossed the early stopping boundary. The absolute difference in disease-free survival between the trastuzumab group and the control group was 12 percent at three years. Trastuzumab therapy was associated with a 33 percent reduction in the risk of death (P=0.015). The three-year cumulative incidence of class III or IV congestive heart failure or death from cardiac causes in the trastuzumab group was 4.1 percent in trial B-31 and 2.9 percent in trial N9831.

CONCLUSIONS

Trastuzumab combined with paclitaxel after doxorubicin and cyclophosphamide improves outcomes among women with surgically removed HER2-positive breast cancer. (ClinicalTrials.gov numbers, NCT00004067 and NCT00005970.)

Response to fulvestrant in heavily pretreated postmenopausal women:a single-center experience

Fulvestrant ('Faslodex') is a new estrogen receptor (ER) antagonist that has no agonist effects. It binds, blocks and accelerates degradation of the ER, leading to a complete abrogation of estrogen-sensitive gene transcription. In postmenopausal women with advanced breast cancer progressing on prior endocrine therapy, fulvestrant is at least as effective as the third-generation aromatase inhibitor (AI) anastrozole. In this single-center experience, 42 postmenopausal patients with metastatic breast cancer who had been heavily pretreated with prior endocrine therapy and chemotherapy were treated with fulvestrant. Prior endocrine therapies included selective ER modulators (including tamoxifen and toremifene), AIs, megestrol acetate, and high-dose estrogens. In total, eight patients (19%) achieved stable disease (SD) for > or =24 weeks, including two patients with SD for 2 years and one with SD for 14 months. Fulvestrant was well tolerated with the majority of adverse events related to the site of metastatic disease. These data demonstrate that fulvestrant is a well tolerated and effective endocrine therapy for postmenopausal women with metastatic breast cancer who have been heavily pretreated with prior therapies. The novel mechanism of action of fulvestrant reduces the likelihood of cross-resistance with other endocrine therapies and therefore this agent may be active in patients who have proved to be resistant to treatments such as tamoxifen or AIs. The use of fulvestrant earlier in the sequence of endocrine treatments may achieve better responses than observed in this heavily pretreated patient population.

Lower-Category Benign Breast Disease and the Risk of Invasive Breast Cancer

BACKGROUND

The risk of invasive breast cancer associated with benign breast disease (BBD) other than atypical hyperplasia and in situ breast cancer, especially with nonproliferative diagnosis, has not been explored extensively. This report evaluates the risk of breast cancer associated with this lower-category BBD (LC-BBD).

METHODS

11 307 women without prior history of atypical hyperplasia or in situ breast cancer at randomization (1992-1997) were identified from the cohort of the National Surgical Adjuvant Breast and Bowel Project's Breast Cancer Prevention Trial. Pathologic findings from breast biopsy reports through August 2002 were reviewed, and Cox proportional hazards models were used to determine the relative risks (RRs) of breast cancer with 95% confidence intervals (CIs). The relative risks of breast cancer for LC-BBD were adjusted for treatment and for breast cancer risk as determined by the modified Gail model.

RESULTS

Of the 11 307 women, 1376 had LC-BBD, of whom 47 developed breast cancer, and of the 9931 women without LC-BBD, 291 developed breast cancer. The RR of breast cancer for women with LC-BBD relative to women without LC-BBD was 1.60 (95% CI = 1.17 to 2.19). Among women 50 years of age and older, the RR of breast cancer for those with LC-BBD was 1.95 (95% CI = 1.29 to 2.93). After adjustment for treatment and breast cancer risk, the RR of breast cancer for women with LC-BBD was 1.41 (95% CI = 1.03 to 1.94).

CONCLUSIONS

Women with LC-BBD had a statistically significant increased risk of breast cancer. The elevation of breast cancer risk was especially evident in women 50 years of age and older. Furthermore, this risk was independent of that associated with key epidemiologic breast cancer risk factors.

Effects of tamoxifen on benign breast disease in women at high risk for breast cancer

BACKGROUND

In 1998 the National Surgical Adjuvant Breast and Bowel Project (NSABP) demonstrated that tamoxifen treatment reduced the incidence of both invasive and noninvasive breast cancer in women at high risk for the disease. We examined the effect of tamoxifen treatment on the incidence of benign breast disease and the number of breast biopsies in the same group of women.

METHODS

We examined the medical records of 13 203 women with follow-up who participated in the NSABP Breast Cancer Prevention Trial. Included in this analysis were women who had undergone a breast biopsy and who had histologic diagnoses of adenosis, cyst, duct ectasia, fibrocystic disease, fibroadenoma, fibrosis, hyperplasia, or metaplasia. The relative risk (RR) for each histologic diagnosis was estimated for women who received tamoxifen and for women who received placebo. We also tallied the number of biopsies that women in the placebo and tamoxifen groups underwent.

RESULTS

Overall, tamoxifen treatment reduced the risk of benign breast disease by 28% (RR = 0.72, 95% confidence interval [CI] = 0.65 to 0.79). Tamoxifen therapy resulted in statistically significant reductions in the risk of adenosis (RR = 0.59, 95% CI = 0.47 to 0.73), cyst (RR = 0.66, 95% CI = 0.58 to 0.75), duct ectasia (RR = 0.72, 95% CI = 0.53 to 0.97), fibrocystic disease (RR = 0.67, 95% CI = 0.58 to 0.77), hyperplasia (RR = 0.60, 95% CI = 0.50 to 0.71), and metaplasia (RR = 0.51, 95% CI = 0.41 to 0.62). Tamoxifen therapy also reduced the risk for fibroadenoma (RR = 0.77, 95% CI = 0.56 to 1.04) and fibrosis (RR = 0.86, 95% CI = 0.72 to 1.03). Compared with the placebo group, the tamoxifen group had 29% (95% CI = 23% to 34%) fewer biopsies (1048 versus 1469) and 19% fewer women who underwent a biopsy (811 versus 1019). This resulted in a 29% reduction in the risk of biopsy in women treated with tamoxifen (RR = 0.71, 95% CI = 0.66 to 0.77). This risk reduction occurred predominantly in women younger than 50 years.

CONCLUSION

Women in this study who received tamoxifen, especially younger women (i.e., <50 years), had a reduced incidence of clinically detected benign breast disease and underwent fewer breast biopsies.

Moving forward: Herceptin in the adjuvant setting

HER2 overexpression/amplification, which is an early event in breast cancer development, is associated with a poor prognosis and may predict response to therapy. Herceptin, an anti-HER2 monoclonal antibody, has shown significant efficacy in the treatment of HER2-positive metastatic breast cancer and appears to provide greater benefit the earlier the drug is given. Moreover, Herceptin also demonstrates a favorable safety profile and is associated with quality-of-life benefits. Taken together, these factors provide the rationale for moving this drug into the adjuvant setting, and four large-scale trials that will involve a total of more than 12,000 women with HER2-positive primary breast cancer have been undertaken to address this issue. In the United States, NSABP trial B31 and the Intergroup N9831 trial will investigate Herceptin in combination with the standard US regimen of anthracycline/cyclophosphamide followed by paclitaxel. Trial BCIRG 006, which is being conducted globally, will examine Herceptin in combination with platinum salts/docetaxel. The HERA Trial, involving countries outside the US, will examine q3-weekly Herceptin monotherapy given for 1 and 2 years after the completion of adjuvant chemo-/radiation therapy. The breadth of the ongoing Herceptin adjuvant trials will potentially allow the optimal treatment approach to be identified.

Real-world performance of HER2 testing--National Surgical Adjuvant Breast and Bowel Project experience

Trastuzumab (Herceptin) provides clinical benefits for patients diagnosed with advanced breast cancers that have overexpressed the HER2 protein or have amplified the HER2 gene. The National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-31 is designed to test the advantage of adding Herceptin to the adjuvant chemotherapeutic regimen of doxorubicin and cyclophosphamide followed by paclitaxel (Taxol) in the treatment of stage II breast cancer with HER2 overexpression or gene amplification. Eligibility is based on HER2 assay results submitted by the accruing institutions. We conducted a central review of the first 104 cases entered in this trial on the basis of immunohistochemistry (IHC) results. We found that 18% of the community-based assays, which were used to establish the eligibility of patients to participate in the B-31 study, could not be confirmed by HercepTest IHC or fluorescence in situ hybridization (FISH) by a central testing facility. This report provides a snapshot of the quality of HER2 assays performed in laboratories nationwide.

Breast cancer chemoprevention: current status and future directions

Cancer prevention is a relatively young concept. Perhaps the greatest strides in cancer research that have been made in the prevention arena have been in breast cancer. In this article we examine the meaning of "prevention" and discuss several of the trials under way or completed, including the National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial. Semin Oncol 28:253-259.