The antibody-drug conjugate trastuzumab-DM1 (T-DM1) combines the biologic activity of trastuzumab with targeted delivery of a potent antimicrotubule agent, DM1, to human epidermal growth factor ...receptor 2 (HER2)-overexpressing cancer cells. Based on results from a phase I study that showed T-DM1 was well tolerated at the maximum-tolerated dose of 3.6 mg/kg every 3 weeks, with evidence of efficacy, in patients with HER2-positive metastatic breast cancer (MBC) who were previously treated with trastuzumab, we conducted a phase II study to further define the safety and efficacy of T-DM1 in this patient population.
This report describes a single-arm phase II study (TDM4258g) that assessed efficacy and safety of intravenous T-DM1 (3.6 mg/kg every 3 weeks) in patients with HER2-positive MBC who had tumor progression after prior treatment with HER2-directed therapy and who had received prior chemotherapy.
With a follow-up of ≥ 12 months among 112 treated patients, the objective response rate by independent assessment was 25.9% (95% CI, 18.4% to 34.4%). Median duration of response was not reached as a result of insufficient events (lower limit of 95% CI, 6.2 months), and median progression-free survival time was 4.6 months (95% CI, 3.9 to 8.6 months). The response rates were higher among patients with confirmed HER2-positive tumors (immunohistochemistry 3+ or fluorescent in situ hybridization positive) by retrospective central testing (n = 74). Higher response rates were also observed in patients whose tumors expressed ≥ median HER2 levels by quantitative reverse transcriptase polymerase chain reaction for HER2 expression, compared with patients who had less than median HER2 levels. T-DM1 was well tolerated with no dose-limiting cardiotoxicity. Most adverse events (AEs) were grade 1 or 2; the most frequent grade ≥ 3 AEs were hypokalemia (8.9%), thrombocytopenia (8.0%), and fatigue (4.5%).
T-DM1 has robust single-agent activity in patients with heavily pretreated, HER2-positive MBC and is well tolerated at the recommended phase II dose.
Cardiac dysfunction (CD) is a recognized risk associated with the addition of trastuzumab to adjuvant chemotherapy for human epidermal growth factor receptor 2-positive breast cancer, especially when ...the treatment regimen includes anthracyclines. Given the demonstrated efficacy of trastuzumab, ongoing assessment of cardiac safety and identification of risk factors for CD are important for optimal patient care.
In National Surgical Adjuvant Breast and Bowel Project B-31, a phase III adjuvant trial, 1,830 patients who met eligibility criteria for initiation of trastuzumab were evaluated for CD. Recovery from CD was also assessed. A statistical model was developed to estimate the risk of severe congestive heart failure (CHF). Baseline patient characteristics associated with anthracycline-related decline in cardiac function were also identified.
At 7-year follow-up, 37 (4.0%) of 944 patients who received trastuzumab experienced a cardiac event (CE) versus 10 (1.3%) of 743 patients in the control arm. One cardiac-related death has occurred in each arm of the protocol. A Cardiac Risk Score, calculated using patient age and baseline left ventricular ejection fraction (LVEF) by multiple-gated acquisition scan, statistically correlates with the risk of a CE. After stopping trastuzumab, the majority of patients who experienced CD recovered LVEF in the normal range, although some decline from baseline often persists. Only two CEs occurred more than 2 years after initiation of trastuzumab.
The late development of CHF after the addition of trastuzumab to paclitaxel after doxorubicin/ cyclophosphamide chemotherapy is uncommon. The risk versus benefit of trastuzumab as given in this regimen remains strongly in favor of trastuzumab.
Botanical therapies are often used by breast cancer patients yet few clinical trials have evaluated their safety and efficacy. We studied mechanisms of activity and performed a phase I clinical trial ...in patients with advanced breast cancer to evaluate BZL101, an aqueous extract from Scutellaria barbata.
Preclinical studies were conducted in vitro to characterize cell death induced by BZL101. In a phase I trial, eligible patients had histologically confirmed, measurable metastatic breast cancer. Treatment consisted of 350 ml per day of oral BZL101, administered as sole cancer therapy until disease progression, toxicity or personal preference to discontinue. Primary endpoints were safety, toxicity and tumor response.
BZL101 extract induced strong growth inhibition and apoptosis of breast cancer cell lines. In the phase I trial, 21 patients received BZL101. Mean age was 54 years (30-77) and mean number of prior treatments for metastatic disease was 3.9 (0-10). There were no grade III or IV adverse events (AEs). The most frequently reported BZL101-related grade I and II AEs included: nausea (38%), diarrhea (24%), headache (19%) flatulence (14%), vomiting (10%), constipation (10%), and fatigue (10%). Sixteen patients were evaluable for response. Four patients had stable disease (SD) for >90 days (25%) and 3/16 had SD for >180 days (19%). Five patients had objective tumor regression, one of which was 1 mm short of a PR based on RECIST criteria.
BZL 101 inhibits breast cancer cell lines by inducing apoptosis. In a phase I clinical trial, BZL101 was safe and had a favorable toxicity profile. BZL101 demonstrated encouraging clinical activity in this heavily pretreated population.
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.
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.
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.
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.)
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.
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.
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.
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.
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.
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.
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.
Node-positive breast cancer patients who developed IBTR or oLRR had significantly poorer prognoses than patients who did not experience these events.
Eribulin mesylate (E7389), a nontaxane microtubule dynamics inhibitor, is a structurally simplified, synthetic analog of the marine natural product halichondrin B. This open-label, single-arm, phase ...II study evaluated efficacy and tolerability of eribulin in heavily pretreated patients with metastatic breast cancer (MBC).
MBC patients who were previously treated with an anthracycline and a taxane received eribulin mesylate (1.4 mg/m(2)) as a 2- to 5-minute intravenous (IV) infusion on days 1, 8, and 15 of a 28-day cycle. Because of neutropenia (at day 15), an alternative regimen of eribulin on days 1 and 8 of a 21-day cycle was administered. The primary end point was overall response rate.
Of the 103 patients treated, the median number of prior chemotherapy regimens was four (range, one to 11 regimens). In the per-protocol population (n = 87), eribulin achieved an independently reviewed objective response rate (all partial responses PRs) of 11.5% (95% CI, 5.7 to 20.1) and a clinical benefit rate (PR plus stable disease > or = 6 months) of 17.2% (95% CI, 10.0 to 26.8). The median duration of response was 171 days (5.6 months; range, 44 to 363 days), the median progression-free survival was 79 days (2.6 months; range, 1 to 453 days), and the median overall survival was 275 days (9.0 months; range, 15 to 826 days). The most common drug-related grades 3 to 4 toxicities were as follows: neutropenia, 64%; leukopenia, 18%; fatigue, 5%; peripheral neuropathy, 5%; and febrile neutropenia, 4%.
Eribulin demonstrated activity with manageable tolerability (including infrequent grade 3 and no grade 4 neuropathy) in heavily pretreated patients with MBC when dosed as a short IV infusion on days 1 and 8 of a 21-day cycle.
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 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.
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.
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.
Background: The finding of a decrease in contralateral breast cancer incidence following tamoxifen administration for adjuvant therapy led to the concept that the drug might play a role in breast ...cancer prevention. To test this hypothesis, the National Surgical Adjuvant Breast and Bowel Project initiated the Breast Cancer Prevention Trial (P-1) in 1992. Methods: Women (N = 13 388) at increased risk for breast cancer because they 1) were 60 years of age or older, 2) were 35–59 years of age with a 5-year predicted risk for breast cancer of at least 1.66%, or 3) had a history of lobular carcinoma in situ were randomly assigned to receive placebo (n = 6707) or 20 mg/day tamoxifen (n = 6681) for 5 years. Gail's algorithm, based on a multivariate logistic regression model using combinations of risk factors, was used to estimate the probability (risk) of occurrence of breast cancer over time. Results: Tamoxifen reduced the risk of invasive breast cancer by 49% (two-sided P<.00001), with cumulative incidence through 69 months of follow-up of 43.4 versus 22.0 per 1000 women in the placebo and tamoxifen groups, respectively. The decreased risk occurred in women aged 49 years or younger (44%), 50–59 years (51%), and 60 years or older (55%); risk was also reduced in women with a history of lobular carcinoma in situ (56%) or atypical hyperplasia (86%) and in those with any category of predicted 5-year risk. Tamoxifen reduced the risk of noninvasive breast cancer by 50% (two-sided P<.002). Tamoxifen reduced the occurrence of estrogen receptor-positive tumors by 69%, but no difference in the occurrence of estrogen receptor-negative tumors was seen. Tamoxifen administration did not alter the average annual rate of ischemic heart disease; however, a reduction in hip, radius (Colles'), and spine fractures was observed. The rate of endometrial cancer was increased in the tamoxifen group (risk ratio = 2.53; 95% confidence interval = 1.35–4.97); this increased risk occurred predominantly in women aged 50 years or older. All endometrial cancers in the tamoxifen group were stage I (localized disease); no endometrial cancer deaths have occurred in this group. No liver cancers or increase in colon, rectal, ovarian, or other tumors was observed in the tamoxifen group. The rates of stroke, pulmonary embolism, and deep-vein thrombosis were elevated in the tamoxifen group; these events occurred more frequently in women aged 50 years or older. Conclusions: Tamoxifen decreases the incidence of invasive and noninvasive breast cancer. Despite side effects resulting from administration of tamoxifen, its use as a breast cancer preventive agent is appropriate in many women at increased risk for the disease. J Natl Cancer Inst 1998;90:1371–88
Uncertainty about the relative worth of doxorubicin/cyclophosphamide (AC) and cyclophosphamide/methotrexate/fluorouracil (CMF), as well as doubt about the propriety of giving tamoxifen (TAM) with ...chemotherapy to patients with estrogen receptor-negative tumors and negative axillary nodes, prompted the National Surgical Adjuvant Breast and Bowel Project to initiate the B-23 study.
Patients (n = 2,008) were randomly assigned to CMF plus placebo, CMF plus TAM, AC plus placebo, or AC plus TAM. Six cycles of CMF were given for 6 months; four cycles of AC were administered for 63 days. TAM was given daily for 5 years. Relapse-free survival (RFS), event-free survival (EFS), and survival (S) were determined by using life-table estimates. Tests for heterogeneity of outcome used log-rank statistics and Cox proportional hazards models to detect differences across all groups and according to chemotherapy and hormonal therapy status.
No significant difference in RFS, EFS, or S was observed among the four groups through 5 years (P =.96,.8, and.8, respectively), for those aged < or = 49 years (P =.97,.5, and.9, respectively), or for those aged > or = 50 years (P =.7,.6, and.6, respectively). A comparison between all CMF- and all AC-treated patients demonstrated no significant differences in RFS (87% at 5 years in both groups, P =.9), EFS (83% and 82%, P =.6), or S (89% and 90%, P =.4). There were no significant differences in RFS, EFS, or S between CMF and AC in patients aged < or = 49 or > or = 50 years. No significant difference in any outcome was observed when chemotherapy-treated patients who received placebo were compared with those given TAM. RFS in both groups was 87% (P =.6), 87% in patients aged < or = 49 (P =.9), and 88% and 87%, respectively (P =.4), in those aged > or = 50 years.
There was no significant difference in the outcome of patients who received AC or CMF. TAM with either regimen resulted in no significant advantage over that achieved from chemotherapy alone.
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