Effects of neratinib on health-related quality of life in women with HER2-positive early-stage breast cancer: longitudinal analyses from the randomized phase III ExteNET trial

BACKGROUND

We report longitudinal health-related quality-of-life (HRQoL) data from the international, randomized, double-blind, placebo-controlled phase III ExteNET study, which demonstrated an invasive disease-free survival benefit of extended adjuvant therapy with neratinib over placebo in human epidermal growth factor receptor-2-positive early-stage breast cancer.

PATIENTS AND METHODS

Women (N  = 2840) with early-stage HER2-positive breast cancer who had completed trastuzumab-based adjuvant therapy were randomly assigned to neratinib 240  mg/day or placebo for 12  months. HRQoL was an exploratory end point. Patients completed the Functional Assessment of Cancer Therapy-Breast (FACT-B) and EuroQol 5-Dimensions (EQ-5D) questionnaires at baseline and months 1, 3, 6, 9, and 12. Changes from baseline were compared using analysis of covariance with no imputation for missing values. Sensitivity analyses used alternative methods. Changes in HRQoL scores were regarded as clinically meaningful if they exceeded previously reported important differences (IDs).

RESULTS

Of the 2840 patients (intention-to-treat population), 2407 patients were evaluable for FACT-B (neratinib, N  = 1171; placebo, N  = 1236) and 2427 patients for EQ-5D (neratinib, N  = 1186; placebo, N  = 1241). Questionnaire completion rates exceeded 85%. Neratinib was associated with a decrease in global HRQoL scores at month 1 compared with placebo (adjusted mean differences: FACT-B total, -2.9 points; EQ-5D index, -0.02), after which between-group differences diminished at later time-points. Except for the FACT-B physical well-being (PWB) subscale at month 1; all between-group differences were less than reported IDs. The FACT-B breast cancer-specific subscale showed small improvements with neratinib at months 3-9, but all were less than IDs. Sensitivity analyses exploring missing data did not change the results.

CONCLUSIONS

Extended adjuvant neratinib was associated with a transient, reversible decrease in HRQoL during the first month of treatment, possibly linked to treatment-related diarrhea. With the exception of the PWB subscale at month 1, all neratinib-related HRQoL changes did not reach clinically meaningful thresholds. ClinicalTrials.gov: NCT00878709.

Abstract P6-17-36: Consensus and disagreement among experts for treatment of patients with HER2+ early-stage breast cancer suggests unmet need for online decision support tool

Treatment (tx) choices for HER2+ early stage breast cancer (EBC) have become increasingly complex. Clinicians and patients must decide 1) which chemotherapy and HER2-targeted agents to use, 2) the sequence of surgery and chemotherapy: either neoadjuvant (neoadj) or adjuvant (adj) tx, and 3) whether to shorten or extend maintenance HER2-targeted tx.

As tx options expand, so does the need for online decision aids. One online decision support tool was developed in 2015 to provide specific tx recommendations for pts with EBC and showed that community healthcare providers (HCPs) did not consistently align with experts for neoadj or adj tx of many pts with EBC (SABCS 2015 Abs P5-09-04).

This study includes analysis of neoadj and adj tx practice patterns of 5 breast cancer experts based on their tx recommendations for 270 unique HER2+ EBC case scenarios made for development of a 2018 online decision tool. We aim to compare these recommendations with the intended treatment of clinicians using the tool.

Results

Experts agree on neoadj tx approaches: initial surgery, no neoadj tx for pts with cT1a/b N0 tumors; neoadj tx before surgery for pts with ≥cT2 or N+ tumors. There was disparity among experts for pts with cT1c N0 disease: 3 experts recommend neoadj TCH±P and 2 recommend proceeding directly to surgery.

Experts generally recommend adj TCHP for pts with stage II N+ or higher HER2+ EBC who did not receive neoadj tx. In addition, 5/5 experts would consider extended adj tx with neratinib for these pts if HR+ and 2/5 experts would also consider neratinib if HR–.

In pts who received neoadj chemo+HER2 tx, post-surgery management depends on response to neoadj tx. For pts with pCR, 5/5 experts generally agree on continuing H+P if both were given as neoadj tx or H alone if only H given as neoadj tx for a total of 1 yr of anti-HER2 Ab tx and 2/5 experts would consider extended adj tx with neratinib for HR+ disease. For pts with residual disease, experts would recommend continuing H+P if both were given as neoadj tx and most would add P for subsequent adj tx if H alone was given to complete a total of 1 yr of anti-HER2 Ab tx (Table1). All experts would consider extended adj tx with neratinib for HR+ disease and 3/5 experts would also consider neratinib for HR– disease. None of the experts recommended less than 12 mos of adj HER2-targeted tx.

We will present analyses of cases entered into our online tool and detailed comparisons of expert and the intended treatment of clinicians using the tool.

Conclusions

Practice patterns are changing rapidly and are more complex in response to the evolving treatment landscape for HER2+ EBC. This analysis highlights several areas of expert consensus; however, disparities remain for select cases. The current tool addresses an unmet medical need for expert-led evaluation of HER2+ EBC tx choices and warrants further investigation.

Expert Recommendations: Initial Adj HER2 Ab Tx After Neodj Tx With H Alone ExpertsResponse12345pCR (HR-)HHHHHpCR (HR+)HHHHHypT1a-c N0 (HR-)H + PHH + PH + PH + PypT1a-c N0 (HR+)H + PHHH + PHypT2 N0 (HR-)H + PH + PH + PH + PH + PypT2 N0 (HR+)H + PH + PHH + PH + PypTany N+ (HR+ or HR-)H + PH + PH + PH + PH + P

Citation Format: Holmes FA, Rosenthal KM, Hurvitz S, Pegram MD, Yardley DA, Obholz KL, O'Shaughnessy J. Consensus and disagreement among experts for treatment of patients with HER2+ early-stage breast cancer suggests unmet need for online decision support tool [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-36.

Syndrome of Inappropriate Antidiuretic Hormone Secretion Associated with Hepatic Arterial Infusion of Vinblastine in Three Patients with Breast Cancer

We report the occurrence of the syndrome of inappropriate antidiuretic hormone secretion in 3 patients with breast carcinoma metastatic to the liver who received hepatic arterial infusion of vinblastine at lower doses than those previously associated with this effect. Leukopenia was severe in all patients, who additionally experienced hypokalemia with excessive kaliuresis. The etiology of the observed hypokalemia is unclear. We suspect that vinblastine may induce renal tubular dysfunction. These toxicities appear dose-related.

Abstract P1-13-05: Timing of initiation of neratinib after completion of trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Exploratory analyses from the phase III ExteNET trial

Background: The international, randomized, placebo-controlled phase III ExteNET trial showed that 1 year of neratinib after trastuzumab-based adjuvant therapy significantly improved 2-year invasive disease-free survival (iDFS) in early-stage HER2+ breast cancer (HR 0.67; 95% CI 0.50–0.91; p=0.009) [Chan et al. Lancet Oncol 2016]. The significant iDFS benefit with neratinib was maintained after a median of 5 years' follow-up (HR 0.73; 95% CI 0.57-0.92; p=0.008) [Martin et al. ESMO 2017]. We present exploratory analyses from the ExteNET trial examining the effects of the interval between completion of trastuzumab and randomization to commence neratinib on iDFS.

Methods: Women with early-stage HER2+ breast cancer were randomly assigned to oral neratinib 240 mg/day or placebo for 1 year after standard primary therapy and trastuzumab-based adjuvant therapy. Under the original study protocol, (neo)adjuvant trastuzumab was to be completed ≤24 months before randomization; this was revised to ≤12 months before randomization after the NCCTG-N9831/NSABP B-31 4-year analysis showed that the risk of relapse is greatest during the first 12 months after completing trastuzumab. Disease recurrences were collected prospectively during 1 and 2 years post-randomization, and from medical records during 3–5 years post-randomization. Patients randomized ≤12 months after completion of adjuvant trastuzumab were further separated to look at those who initiated neratinib ≤6 months of completing adjuvant trastuzumab. Primary endpoint: iDFS. HR (95% CI) estimated using Cox proportional-hazards models. Data cut-off: March 1, 2017. Clinicaltrials.gov: NCT00878709.

Results:The intention-to-treat population comprised 2840 patients (neratinib, n=1420; placebo, n=1420). Median time from last trastuzumab dose to randomization was 4.4 and 4.6 months in the neratinib and placebo groups, respectively. 81% of patients were randomized ≤12 months of completing trastuzumab. The effects of the interval between the last dose of trastuzumab and randomization/initiation of neratinib on iDFS after a median follow-up of 5.2 years are shown in the table.

  Estimated 5-year iDFS rate, % P-valueInterval from last dose of trastuzumab to randomizationnNeratinibPlaceboHR (95% CI)a(2-sided)≤6 months164190.085.40.62 (0.46–0.84)0.002≤12 monthsb229789.786.50.70 (0.54–0.90)0.006>12 monthsb54392.392.61.00 (0.51–1.94)0.992a. Neratinib vs placebo; b. Protocol-defined subgroups

Conclusions: In ExteNET, patients who initiated neratinib within 12 months of completing trastuzumab-based adjuvant therapy appeared to derive greater benefit from treatment than those who started neratinib later. Further, exploratory analyses suggest that the magnitude of benefit with neratinib is greater if initiated sooner (i.e. within 6 months of completing trastuzumab). Given the benefits of neratinib overall in those initiating treatment ≤12 months from the end of adjuvant trastuzumab, extended adjuvant treatment with neratinib should be initiated early following completion of trastuzumab.

Citation Format: Ejlertsen B, Chan A, Gnant M, von Minckwitz G, Delaloge S, Buyse M, O'Shaughnessy J, Mansi J, Moy B, Iwata H, Wong A, Ye Y, Means-Powell J, Hui R, Ruiz-Borrego M, Ruiz Simon A, Shen Z-Z, Holmes FA, Lesniewski-Kmak K, Martin M. Timing of initiation of neratinib after completion of trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Exploratory analyses from the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-05.

Abstract P1-07-18: Clinicopathologic and molecular correlates of breast cancer index (BCI) results in patients with HR+, LN- breast cancer that are high risk of late distant recurrence (DR) / low likelihood of benefit from extended endocrine therapy (EET)

Background: BCI is a gene expression assay for patients with early stage HR+ breast cancer that provides 2 results: BCI Predictive, based on the HoxB13/IL17BR (H/I) ratio, reports a prediction of high vs low likelihood of benefit from EET; BCI Prognostic, based on the algorithmic combination of H/I and a set of proliferation-based genes, reports the risk of late distant recurrence (DR). Clinical actionability is distinct based on the 4 possible combinations of prognostic and predictive results. To better characterize patients classified by BCI as having a high risk of late DR but a low likelihood of benefit from EET, we assessed clinicopathologic and molecular correlates in this subset.

Methods: The BCI Clinical Database for Correlative Studies is a de-identified database containing >50 clinicopathologic and molecular variables from cases submitted for BCI in clinical practice (N=19,126). Clinicopathologic variables abstracted from pathology reports were available for a subset of these cases. Molecular proliferation status (molecular grade index [MGI]) and clinicopathologic parameters were examined in the 4 possible BCI result categories of BCI Prognostic (High vs Low risk) and BCI Predictive (High vs Low H/I). Chi-squared tests and ANOVA were used to compare BCI results within subsets.

Results: Analyses included 3843 LN- pts with clinicopathologic data: Median age was 59.1y (range 26-89y; 74% ≥50y); 30.9%, 51.7%, and 17.4% were Grade 1, 2, and 3, respectively; 27.8%, 48.9%, 21.7%, and 1.6% were T1a/b, T1c, T2, and T3, respectively. BCI categorized 41.4% of pts as having Low risk/Low likelihood of benefit, 31.3% with High risk/High benefit, 18.0% with High risk/Low benefit, and 9.3% with Low risk/High benefit. Patients with High Risk/Low Benefit had increased median proliferation scores (MGI), and a greater proportion of pts with grade 2/3 tumors and high Ki67 scores compared to pts with Low Risk/Low Benefit (P<.0001 for all). In contrast, there were only modest differences in clinicopathologic parameters between patients with High Risk/ Low Benefit and those with High Risk/High Benefit.

Conclusion: In characterizing the molecular and clinical correlates in BCI cases with a high risk of late DR but low likelihood of benefit from EET, we found that higher proliferative status was associated with classification of high risk of DR. Future studies might investigate whether patients with this molecular pattern might benefit from combinatorial therapy (e.g., CDK 4/6 inhibitors) with EET. This study highlights the importance of predictive biomarkers for individualized EET therapy recommendation.

Citation Format: Royce M, Poage G, Israel MA, Schnabel CA, Holmes FA. Clinicopathologic and molecular correlates of breast cancer index (BCI) results in patients with HR+, LN- breast cancer that are high risk of late distant recurrence (DR) / low likelihood of benefit from extended endocrine therapy (EET) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-18.

Abstract P1-13-03: Effects of neratinib after trastuzumab-based adjuvant therapy in hormone receptor-positive HER2+ early-stage breast cancer: Exploratory analyses from the phase III ExteNET trial

Background: The international, randomized, placebo-controlled phase III ExteNET trial showed that a 1-year course of neratinib after trastuzumab-based adjuvant therapy significantly improved 2-year invasive disease-free survival (iDFS) in patients with early-stage HER2+ breast cancer (BC) (hazard ratio 0.67; 95% CI 0.50–0.91; p=0.009) [Chan et al. Lancet Oncol 2016]. The significant iDFS benefit with neratinib was maintained after a median 5 years' follow-up (hazard ratio 0.73; 95% CI 0.57-0.92; p=0.008) [Martin et al. ESMO 2017]. At both time-points, marked benefit with neratinib was evident in patients with hormone receptor (HR)+ tumors, whereas in patients with HR– disease, initial improvements with neratinib diminished after completing treatment. We report exploratory analyses from the ExteNET trial done to better characterize the effects of neratinib in the HR+ subgroup.

Methods: Patients with early-stage HER2+ BC were randomly assigned to oral neratinib 240 mg/day or placebo for 1 year after standard primary therapy and trastuzumab-based adjuvant therapy. Randomization was stratified by HR status (locally assessed), nodal status, and trastuzumab regimen. Adjuvant endocrine therapy was recommended for patients with HR+ disease. Data concerning disease recurrences were collected prospectively during year 1-2 post-randomization, and from medical records during year 3–5 post-randomization. Primary endpoint: iDFS. Secondary endpoints: DFS including ductal carcinoma in situ (DFS-DCIS); time to distant recurrence (TTDR); distant DFS (DDFS); cumulative incidence of central nervous system (CNS) recurrences; overall survival (OS). Hazard ratios (95% CI) were estimated using Cox proportional-hazards models. Data cut-off: March 2017. Clinicaltrials.gov: NCT00878709.

Results: 2840 patients were randomized (neratinib, n=1420; placebo, n=1420); 1631 (57%) patients had HR+ tumors (neratinib, n=816; placebo, n=815). 93% and 94% of HR+ patients in the neratinib and placebo groups, respectively, were receiving adjuvant endocrine therapy at baseline. Efficacy outcomes in the HR+ cohort after a median follow-up of 5.2 years are shown in the table. In subgroup analyses of the HR+ cohort, hazard ratios for iDFS were 0.49 in centrally confirmed HER2+ patients (n=951), and 0.58 in patients who had completed prior trastuzumab ≤12 months before randomization (n=1334). CNS recurrence and OS data are not yet mature.

 Updated 2-year analysis5-year analysis  Hazard ratiobP-value Hazard ratiobP-value Δ, %a(95% CI)(2 sided)Δ, %a(95% CI)(2 sided)iDFS4.10.49 (0.31–0.75)0.0014.40.60 (0.43–0.83)0.002DFS-DCIS4.80.45 (0.29–0.69)<0.0015.10.57 (0.42–0.79)<0.001DDFS3.10.52 (0.32–0.84)0.0084.00.60 (0.42–0.85)0.004TTDR2.90.52 (0.31–0.85)0.013.80.61 (0.42–0.86)0.006a. Difference in event rates between neratinib vs placebo; b. Neratinib vs placebo

Conclusions: Neratinib was associated with an absolute iDFS benefit of 4.4% in patients with HR+/HER2+ BC after 5 years' follow-up. HR/HER2 receptor cross-talk may underpin the notable effect of neratinib in patients with HR+ tumors when given in combination with endocrine therapy.

Citation Format: Chia SKL, Martin M, Iwata H, Moy B, Lalani AS, Holmes FA, Mansi J, von Minckwitz G, Buyse M, Delaloge S, Ejlertsen B, Yao B, Murias Rosales A, Hellerstedt B, Cold S, Inoue K, Shen Z-Z, Galeano T, Barrios CH, Chan A. Effects of neratinib after trastuzumab-based adjuvant therapy in hormone receptor-positive HER2+ early-stage breast cancer: Exploratory analyses from the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-03.

Abstract PD3-12: PIK3CA alterations and benefit with neratinib after trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Correlative analyses of the phase III ExteNET trial

Background: Neratinib is a pan-HER tyrosine kinase inhibitor that blocks the PI3K/Akt and MAPK signaling pathways downstream from HER2. The international, randomized, placebo-controlled phase III ExteNET trial showed that a 1-year course of neratinib after trastuzumab-based adjuvant therapy significantly improved 2-year invasive disease-free survival (iDFS) in early-stage HER2+ breast cancer (HR 0.67; 95% CI 0.50–0.91; p=0.0091) [Chan et al. Lancet Oncol 2016]. Furthermore, the effects of neratinib on iDFS were shown to be durable at 5 years' follow-up (HR 0.73; 95% CI 0.57–0.92; p=0.008) [Martin et al. ESMO 2017]. PIK3CA alterations are common in HER2+ breast cancers, and in general are associated with a worse prognosis. We sought to assess the prognostic and predictive significance of PIK3CA alterations in an exploratory substudy of the ExteNET trial.

Methods: ExteNET is an international, multi-center, randomized, double-blind, placebo-controlled phase III trial (Clinicaltrials.gov: NCT00878709). Patients received oral neratinib 240 mg/day or placebo for 1 year. Of the intent-to-treat (ITT) population (n=2840), primary formalin-fixed paraffin-embedded (FFPE) tumor specimens were available from 991 patients for PIK3CA mutation testing by RT-PCR for two hot-spot mutations in exon 9 (E542K, E545K/D) and one hot-spot mutation in exon 20 (H1047R). 702 FFPE tumor slides underwent FISH analysis for PIK3CA amplification with a ratio of ≥2.2 considered as amplified. Primary endpoint: iDFS. iDFS events were tested by 2-sided log-rank tests, and HR (95% CI) were estimated using Cox proportional-hazards models. Data cut-off: March 2017.

Results: Baseline demographics and disease characteristics between treatment arms of the correlative cohort (n=1201) were balanced. Overall, 21.2% (n=210) of primary tumors harbored one of the specified PIK3CA mutations, and 8.7% (n=61) were PIK3CA FISH-amplified. Patients with PIK3CA-altered tumors (i.e. PIK3CA mutations or FISH-amplified) had fewer iDFS events with neratinib compared with placebo (HR 0.41; 95% CI 0.17-0.90, p=0.028). The interaction test was not significant (p=0.1842). Results of the various correlative analyses within treatment arms are shown in the table.

 NeratinibPlacebo   iDFS iDFS 2-sidedPopulationnevents, nnevents, nHR (95% CI)P valueaITT142011614201630.73 (0.57–0.92)b0.008bCorrelative cohort59345608700.67 (0.45–0.96)0.0317PIK3CA-mutation positive1047106170.43 (0.17–1.01)0.056PIK3CA-mutation negative38527396420.66 (0.40-1.06)0.089PIK3CA-amplified3312840.20 (0.01-1.33)0.106PIK3CA-non-amplified31629325360.85 (0.52-1.39)0.521PIK3CA-altered1308132200.41 (0.17-0.90)0.028a. Log-rank test; b. Stratified analysis

Conclusions: One year of neratinib treatment after trastuzumab-based adjuvant therapy significantly improves iDFS after 5 years in patients with early-stage HER2+ breast cancer. From this modest-sized exploratory cohort, it appears that PIK3CA may be a biomarker for differential sensitivity to neratinib after 1 year of trastuzumab in the adjuvant setting.These exploratory results should be validated in a larger subset.

Citation Format: Chia SKL, Martin M, Holmes FA, Ejlertsen B, Delaloge S, Moy B, Iwata H, von Minckwitz G, Mansi J, Barrios CH, Gnant M, Tomašević Z, Denduluri N, Šeparović R, Kim S-B, Hugger Jakobsen E, Harvey V, Robert N, Smith II J, Harker G, Lalani AS, Zhang B, Eli LD, Buyse M, Chan A. PIK3CA alterations and benefit with neratinib after trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Correlative analyses of the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD3-12.

Abstract P2-08-01: Results from a randomized placebo-controlled phase 2 trial evaluating exemestane ± enzalutamide in patients with hormone receptor–positive breast cancer

This abstract was withdrawn by the authors.

Abstract P6-09-01: Central Ki67 analysis as a predictor for adjuvant capecitabine efficacy in early breast cancer (EBC) subtypes in US oncology trial 01062

Background: USON 01062 (O’Shaughnessy J, et al. Proc SABCS, 2010, abst S4-2) showed no improvement in the primary endpoint of disease-free survival (DFS) (median FU 5 yrs: HR 0.84, 95% CI: 0.67-1.05; p = 0.125) with the addition of capecitabine (X) to standard adjuvant chemotherapy, but showed improvement in OS (HR 0.68, 95% CI: 0.51-0.92; p = 0.011). Exploratory analysis of local pathology-assessed Ki67 suggested benefit from adjuvant X in pts with more highly proliferative cancers with Ki67 ≥ 10% (Pippen J et al. Proc ASCO, 2011, abst 500). The objective of this study is to determine whether centrally-performed Ki67 IHC results corroborate or refute this finding.

Methods: 2610 pts with resected high risk EBC were randomized to receive 4 cycles of AC (doxorubicin 60mg/m2 and cyclophosphamide 600mg/m2) IV every 3 wks for 4 cycles followed by either docetaxel 100mg/m2 IV or docetaxel 75mg/m2 IV plus X 825mg/m2 PO bid for 14 days every 3 wks for 4 cycles. Archival primary breast cancer tissue was collected on 2000 pts for predictive biomarker analyses. Central Ki67 IHC was performed using the anti-Ki67 monoclonal antibody SP6 and was read by one pathologist (HK) according to published recommendations (Dowsett M, et al. JNCI 103:1-9, 2011).

Results: Central Ki67 IHC has been performed on 1440 pts who had centrally-validated informed consents. The distribution of% Ki67-positive cells by locally-assessed ER/HER2 subtype is shown below. 45% of HR+ HER2- BCs had a Ki67 ≤ 10%, while 24% had a Ki67 11% to 20%, and 31% had a Ki67 > 20%. The concordance between the local vs central Ki67 results was low at 46% for Ki67 <10%, 49% for Ki67 10%-20%, and 76% for Ki67 > 20%. The central Ki67 results tended to be higher than the local testing results. Central mRNA classifiers were developed for ER, PR, HER2 and Ki67 using Fluidigm Microfluidics Dynamic Arrays and correlate highly with central IHC assessment of these markers.

Conclusions: HR+ HER2- EBC is enriched for cancers with a low proliferative rate, a group of pts unlikely to benefit from the cell cycle-specific cytotoxic agent, capecitabine. Analyses of the impact of adjuvant X added to AC/T in EBC pts according to ER status, and according to Ki67 (analyzed as a binary and continuous variable) will be performed prior to SABCS, 2013.

Number of Patients% Ki67 Pos CellsTotal *HR+TNHER2+/HR+HER2+/ HR-0-104163622222711-151391066151016-20126871615821-3018411539201031-1005751403423555Total144081042510790*Totals do not equal sum of subtype categories due to missing HER2 information

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-09-01.

Abstract P3-06-12: Effect of TOP2A and cMYC gene copy number on outcome in a Phase II trial of adjuvant TC (Docetaxel/Cyclophosphamide) plus trastuzumab (HER TC) in HER2-positive early stage breast cancer

Introduction: Approximately one-third of HER2+ early stage breast cancer (ESBC) patients have TOP2A-amplified breast cancer, the subpopulation known to benefit from anthracycline use (Press et al, JCO 2011). Data are needed to evaluate whether outcomes in ESBC patients treated with nonanthracycline-based regimens like docetaxel and cyclophosphamide + trastuzumab (HER TC) are affected by TOP2A or cMYC gene copy number.

Methods: This was an open-label, phase II study of HER TC in HER2+ breast cancer patients. Outcome data have been previously reported (Jones et al, SABCS 2011, PD07-03). Tissue was collected to review HER2, cMYC, and TOP2A gene copy number at a central reference laboratory. HER2, cMYC, and TOP2A amplification was defined as FISH ratio >2, and deletion was defined as FISH ratio <1. Every 21 days, patients received T 75mg/m2 IV and C 600mg/m2 IV, plus weekly H 4mg/kg IV (loading dose) and 2mg/kg IV thereafter for a total of 4 cycles. After 4 cycles of TC+H, patients continued on H for 1 year on a 3-week schedule. The primary endpoint was disease-free survival (DFS) at 2 years with continued follow-up for 3 years. Secondary endpoints were overall survival (OS) and safety.

Results: 493 patients with HER2+ ESBC were enrolled. From the 493 patients, 438 (89%) tissue samples were available and analyzed at Caris Diagnostics (Phoenix, AZ) to test for TOP2A, cMYC, and HER2 gene copy number by FISH. HER2 status was confirmed as positive in 87% of samples. Results for TOP2A, cMYC, and HER2 were generated in 438, 436, and 438 samples, respectively. TOP2A was classified as amplified in 43%, normal in 30%, deleted in 27%. cMYC was classified as amplified in 99(23%), normal in 246(56%), and deleted in 91(21%). Three-year DFS and OS in TOP2A and cMYC status as well as ER and Nodal status are depicted in Table 1. Multivariate analyses of age, nodal status, ER status, and gene expression shown below in Table 2 indicate that neither cMYC nor TOP2A status had an effect on outcome. Only nodal and ER status affected outcome.

P3-16-18: Phase 2, Open-Label Study of EZN-2208 (PEG-SN38) in Patients with Previously Treated Metastatic Breast Cancer

Background

EZN-2208 is a water-soluble PEGylated conjugate of SN38 that results in parenteral delivery, increased solubility, higher exposure, and longer apparent half-life of SN38, as well as more profound deoxyribonucleic acid (DNA) damage and inhibition of angiogenesis. EZN-2208 results in prolonged exposure of tumors to SN38 via preferential accumulation of EZN-2208 in the tumor and prolonged release of SN38 in the blood.

Methods: This trial evaluated EZN-2208 delivered as a 1-h IV infusion weekly for 3 wks in 4-wk cycles. The primary objective was to determine the overall response rate (RR) in female patients with metastatic breast cancer (MBC) who had received prior adjuvant or metastatic therapy with either 1) anthracycline and taxane (AT) or 2) anthracycline, taxane, and capecitabine (Xeloda®) (ATX). Secondary objectives included evaluation of RR based on tumor receptor status, duration of response, progression-free survival (PFS), overall survival (OS), and safety and toxicity. Response was evaluated using RECIST (v1.1).

Results: 148 patients received EZN-2208 in the AT (n=65; median age = 56 y [31-84 y]) or ATX (n=83; median age = 55 y [36-83 y]) cohorts. All 65 patients in the AT cohort had received 0–2 lines of prior cytotoxic therapy for MBC; for the ATX cohort, 31 patients (37%) had received 0–2 prior lines of cytotoxic therapy for MBC, 50 patients (60%) had received 3–4 prior lines, and 2 patients (2%) had received 5 prior lines. Preliminary results follow; final data will be presented at the meeting. Median (range) cycles of EZN-2208 was 2.3 (0.3-14) for AT and 2 (0.3-15) for ATX. Best overall response is shown in the table. RR (PR+uPR) was 22% for AT and 10% for ATX.

Median (95% CI) time to progression was 3.8 mo (3.6−7.4) for AT and 3.3 mo (1.8−3.7) for ATX. Median (95% CI) duration of response was 4.0 mo (3.7−5.6) for AT and 5.2 mo (1.9-..) for ATX. 6-mo PFS (95% CI) was 34% (19%-50%) for AT and 19% (9%-29%) for ATX. Median PFS (95% CI) was 3.8 mo (2.7−5.6) for AT and 2.9 mo (1.83.7) for ATX. Median OS (95% CI) was 9.1 mo (6.1−12.7) for AT and 7.9 mo (6.4−12.9) for ATX. Grade 3 or 4 drug-related adverse events (>10% of patients in either arm) included neutropenia (43%, 33%), diarrhea (11%, 8%), and leukopenia (11%, 6%).

P5-18-09: The Incidence of Febrile Neutropenia in the First Course of Adjuvant Chemotherapy with Docetaxel/Cyclophosphamide with or without Pegfilgrastim

Background

In our original doxorubicin-cyclophosphamide/docetaxel-cyclophosphamide (AC/TC) adjuvant study (JCO 27: 1177–1183, 2009), we reported an incidence of febrile neutropenia (FN) of 5% (8% in women ≥65 years) with the TC regimen without prophylactic WBC growth factors but with a recommendation for prophylactic antibiotics. There is a paucity of data on the incidence of FN with the TC regimen aside from this clinical trial. Because we have been conducting a randomized adjuvant study of TC compared to other regimens, we used this opportunity to analyze the incidence of FN during the first course of chemotherapy with TC in the first cohort of randomized patients (US Oncology Network study 06090). The prophylactic use of WBC growth factors was at the investigator's discretion.

Patients and Methods

The study included 1298 patients entered between May 2007 and May 2009. Of these, 649 were included in the TC arm. Median age was 54 years (range 27–71), 75.5% were Caucasian, 561 (86.4%) were in PS 0 at baseline, and about half were node negative. Eight patients did not receive study treatment for various reasons. Among the 641 patients who received TC; 213 (33.3%) received pegfilgrastim, 48 (7.5%) received filgrastim and were not included in this analysis, and 380 (59.2%) patients did not receive either during the first cycle. Thus, this analysis focused on 593 women who did or did not receive prophylactic pegfilgrastim in cycle 1.

Results: All patients with a reported adverse event of FN or with a reported AE of fever with some degree of neutropenia (in order to capture all possible cases of FN) during the first cycle of TC were identified [Table 1]. FN and fever + neutropenia occurred in a total of 6 (2.8%) patients who received pegfilgrastim and 36 (9.5%) patients who did not. A comparison of age, race, performance status and stage of disease between these 2 groups revealed that they were similar. The 213 patients who received pegfilgrastim were slightly older (median 56 years, range 27–71) compared to those who did not (median 53 years, range 30–71).

Preliminary safety and activity results of trabectedin in a phase II trial dedicated to triple-negative (ER-, PR-, HER2-), HER2+++, or BRCA1/2 germ-line-mutated metastatic breast cancer (MBC) patients (pts)

1010

Background: Trabectedin ([T]; Yondelis) binds to the minor groove of DNA; its cytotoxicity is determined by the synergistic action of two DNA repair mechanisms, the efficient nucleotide excision repair (NER) and deficient homologous recombination repair (HRR) machinery. T has EMEA authorization in soft tissue sarcoma after failure of standard treatment. Preliminary data have shown activity of T as single agent in MBC. Clinical and preclinical data suggested T may display specific activity among certain NER-intact or HRR-deficient MBC, and prompted this phase II trial dedicated to 3 subgroups: triple-negative (TN), HER-2-overexpressed, and BRCA1/2 germline-mutated MBC. Methods: T was given at 1.3 mg/m2 as a 3- hour iv infusion every 3 weeks to pts with pretreated progressive MBC: Group A: TN; Group B: HER-2+++; Group C: BRCA1/2 mutation carriers. Endpoints were objective response (OR) rate by RECIST, duration of response, progression free survival (PFS), tumor volume changes, safety and exploratory pharmacogenomics (PGx). Results: A total of 95 women (median [med] age 52, ECOG 0/1 48/52%) have been enrolled (A:50, B:24, C:21) with data available for 72 pts. Med number of prior chemotherapy regimens: 4 (1–10). Med number of T cycles administered: 2 (1–12) for all groups. The most commonly reported grade 3/4 AEs are neutropenia (29/21%), ALT (28/2%) and AST (13/0). Alopecia/stomatitis, only G1, was reported in <2% each. Long-lasting disease stabilizations were described in all groups. While OR were rare among TN MBC pts (2PR/43 evaluable), preliminary analysis by investigator shows efficacy in group C (4PR/11 evaluable). Tissue samples from 36 pts were collected for RNA expression analysis (XPG + ERCC1 + BRCA1). Preliminary results show high XPG is associated with longer PFS: 4.1 months (95% CI 2.6-not reached) versus 1.3 months (95% CI 1.2–3.7), p = 0.01. Analyses are ongoing. Conclusions: Trabectedin shows a manageable safety profile in the 3 groups of MBC with promising efficacy in certain DNA-repair machinery sub-categories defined molecularly. TN group was closed due to low response. More mature PGx results will be discussed to help selecting the patients who are at highest chance for response.

[Table: see text]

Pharmacogenomic analysis of needle biopsies obtained before preoperative docetaxel/capecitabine/FEC (TX/FEC) chemotherapy for breast cancer

10595

Background: Our goal was to evaluate the feasibility of obtaining fine needle biopsies, for pharmacogenomic analysis, in community based oncology practices and develop gene expression-based predictors of pathologic complete response (pCR) to preoperative sequential docetaxel/capecitabine and 5-fluorouracil, epirubicin, cyclophosphamide chemotherapy. Methods: One hundred seventy-five patients were accrued at 29 sites in the US Oncology Research network. FNA specimens were mailed to a central laboratory (MDACC) and gene expression profiling was performed on Affymetrix U133A chips. Results: RNA extraction was started on 140 specimens, 112 of these (80%) yielded ≥1 μg total RNA, 69 were hybridized and 65 (94%) gene expression profiles have passed quality control as of abstract submission date. The analysis plan is to develop a multigene predictor of pCR from the first 80 cases and test its performance independently in the remaining cases. Conclusions: Collection of mandatory research FNA biopsies for pharmacogenomic research is feasible in community practice. Approximately 80% of biopsies yield sufficient RNA for gene expression profiling. In 20% of patients, either technical factors, which can be addressed, or tumor biology (necrotic, rapidly growing tumors) were limiting. Supported by Roche Laboratories, Inc., Nutley, NJ; Pfizer, New York, NY; and Precision Therapeutics, Pittsburgh, PA.

[Table: see text]

Comparable efficacy and safety profiles of once-per-cycle pegfilgrastim and daily injection filgrastim in chemotherapy-induced neutropenia: a multicenter dose-finding study in women with breast cancer

BACKGROUND

Neutropenia is common in patients receiving myelotoxic chemotherapy. Pegfilgrastim, a sustained-duration filgrastim is a once-per-cycle therapy for prophylactic neutrophil support.

PATIENTS AND METHODS

Women, treated with four cycles of doxorubicin/docetaxel chemotherapy every 21 days, received pegfilgrastim or filgrastim 24 h after chemotherapy as a single subcutaneous injection per chemotherapy cycle (pegfilgrastim 30, 60 or 100 microg/kg) or daily subcutaneous injections (filgrastim 5 microg/kg/day). Safety, efficacy and pharmacokinetics were analyzed.

RESULTS

The incidence of grade 4 neutropenia in cycle 1 was 95, 90 and 74%, in patients who received pegfilgrastim 30, 60 and 100 microg/kg, respectively, and 76% in patients who received filgrastim. Mean duration of grade 4 neutropenia in cycle 1 was 2.7,2 and 1.3 days for doses of pegfilgrastim, and 1.6 days for filgrastim. The pharmacokinetics of pegfilgrastim were non-linear and dependent on both dose and neutrophil count. Pegfilgrastim serum concentration was sustained until the neutrophil nadir occurred then declined rapidly as neutrophils started to recover, consistent with a self-regulating neutrophil-mediated clearance mechanism. The safety profiles of pegfilgrastim and filgrastim were similar.

CONCLUSIONS

A single subcutaneous injection of pegfilgrastim 100 microg/kg provided neutrophil support and a safety profile comparable to daily subcutaneous injections of filgrastim during multiple chemotherapy cycles.

Blinded, randomized, multicenter study to evaluate single administration pegfilgrastim once per cycle versus daily filgrastim as an adjunct to chemotherapy in patients with high-risk stage II or stage III/IV breast cancer

PURPOSE

This multicenter, randomized, double-blind, active-control study was designed to determine whether a single subcutaneous injection of pegfilgrastim (SD/01, sustained-duration filgrastim; 100 microg/kg) is as safe and effective as daily filgrastim (5 microg/kg/d) for reducing neutropenia in patients who received four cycles of myelosuppressive chemotherapy.

PATIENTS AND METHODS

Sixty-two centers enrolled 310 patients who received chemotherapy with docetaxel 75 mg/m(2) and doxorubicin 60 mg/m(2) on day 1 of each cycle for a maximum of four cycles. Patients were randomized to receive on day 2 either a single subcutaneous injection of pegfilgrastim 100 microg/kg per chemotherapy cycle (154 patients) or daily subcutaneous injections of filgrastim 5 microg/kg/d (156 patients). Absolute neutrophil count (ANC), duration of grade 4 neutropenia, and safety parameters were monitored.

RESULTS

One dose of pegfilgrastim per chemotherapy cycle was comparable to daily subcutaneous injections of filgrastim with regard to all efficacy end points, including the duration of severe neutropenia and the depth of ANC nadir in all cycles. Febrile neutropenia across all cycles occurred less often in patients who received pegfilgrastim. The difference in the mean duration of severe neutropenia between the pegfilgrastim and filgrastim treatment groups was less than 1 day. Pegfilgrastim was safe and well tolerated, and it was similar to filgrastim. Adverse event profiles in the pegfilgrastim and filgrastim groups were similar.

CONCLUSION

A single injection of pegfilgrastim 100 microg/kg per cycle was as safe and effective as daily injections of filgrastim 5 microg/kg/d in reducing neutropenia and its complications in patients who received four cycles of doxorubicin 60 mg/m(2) and docetaxel 75 mg/m(2).

Pharmacokinetic profiles of doxorubicin in combination with taxanes

Paclitaxel and docetaxel each possess unique chemical and pharmacologic characteristics that account for significant differences in their potencies, toxicologic and pharmacokinetic profiles, and propensity for drug-drug interactions. Results from phase I/II trials of paclitaxel in combination with doxorubicin showed excellent antitumor activity. However, the high incidence of congestive heart failure warranted further investigation. A sophisticated pharmacokinetic study showed that paclitaxel enhances the nonlinearity of doxorubicin pharmacokinetics and significantly decreases the systemic clearance of both doxorubicin and doxorubicinol. The paclitaxel/doxorubicin interaction was found to be paclitaxel-dose dependent, doxorubicin concentration-dependant, and may be the result of competition for elimination mechanisms, possibly competition for hepatic and biliary transporter proteins such as p-glycoprotein, as a result of the formulation vehicle polyethoxylated castor oil (cremophor EL). Phase I/II trials of the docetaxel/doxorubicin combination also show high antitumor activity, but without an increase in anthracycline-induced congestive heart failure. Subsequent pharmacokinetic investigations show minimal alterations in the pharmacokinetic profiles of doxorubicin or docetaxel when used in combination. While both paclitaxel and docetaxel may be effectively combined with doxorubicin in the treatment of metastatic breast cancer, the drug-drug interaction between paclitaxel and doxorubicin (but not of docetaxel and doxorubicin) warrants that certain restrictions be followed for safe use.

Phase I-II vinorelbine (Navelbine) by continuous infusion in patients with metastatic breast cancer: cumulative toxicities limit dose escalation

Vinorelbine (Navelbine) has significant activity against breast carcinoma and is less neurotoxic than vinblastine. Because vinblastine has improved activity when administered by continuous infusion, we conducted a Phase I-II study to determine the maximum tolerated dose (MTD) of vinorelbine when given by continuous infusion and the response rates to it in heavily pretreated metastatic breast cancer patients. Between April 1994 and August 1997, 87 patients were entered in the study. All were female and had proven metastatic breast cancer. Ninety-five percent of them had received prior doxorubicin treatment, and 74% had received prior paclitaxel treatment. In Phase I of the study, all patients received 8 mg of vinorelbine by intravenous (i.v.) bolus followed by a continuous infusion of vinorelbine over 96 hr. When the MTD was determined, patients were entered in the Phase II arm to assess treatment responses and cumulative toxic reactions. In the Phase I arm (43 patients, 182 cycles), we determined the MTD of vinorelbine to be 8 mg by i.v. bolus followed by a continuous infusion of 11 mg/m2/day over 4 days. The dose-limiting toxic reaction was grade 3-4 granulocytopenia in 35% of the cycles and neutropenic fever in 15% of the cycles. Forty-four patients (193 cycles) were treated at the MTD. Seven (16%) of them had a response (2 complete responses, 5 partial responses). The median durations of response and survival were 4.3 and 8.6 months, respectively. However, cumulative toxic reactions (neutropenic fever and stomatitis) in 22 patients (50%) required dose reductions. A continuous infusion of vinorelbine can be safely administered but with a narrow therapeutic index because of cumulative toxic reactions. We recommend a modified MTD of vinorelbine: 8 mg by i.v. bolus followed by a continuous infusion of 10 mg/m2/day over 4 days. However, this treatment schedule offers no apparent advantage over the commonly used weekly vinorelbine schedule.

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.

Phase II study of paclitaxel in patients with metastatic breast carcinoma refractory to standard chemotherapy

BACKGROUND

The authors conducted a single institution Phase II clinical trial to determine whether paclitaxel had antitumor activity in patients with metastatic breast carcinoma that was refractory to standard chemotherapy.

METHODS

Patients with metastatic breast carcinoma were eligible for the study if they had disease progression after at least 2 prior chemotherapy regimens. Patients who had received three prior regimens were treated in a separate cohort. All patients were required to have received doxorubicin in the past and were not eligible if they had received prior therapy with paclitaxel. The starting dose of paclitaxel for low risk patients was 175 mg/m2, administered as a 24-hour continuous infusion; the starting dose of paclitaxel was 150 mg/m2 for patients who had received > or = 3 prior regimens. Therapy was given every 3 weeks and continued for at least 2 courses unless there was evidence of rapidly progressing disease, for at least 3 courses if there was no change in disease and Grade 3 or 4 (based on National Cancer Institute toxicity criteria) toxicity was not noted, and for 6 courses beyond the maximum response in patients who demonstrated complete or partial responses and showed no evidence of disease progression.

RESULTS

Sixty-eight of 69 patients entered in the study were evaluable for response: 35 patients who had received 2 prior chemotherapy regimens for Stage IV disease and 33 patients who had received > or =3 prior regimens. A partial response was observed in 7 patients who had received 2 prior regimens, for an objective response rate of 20% (95% confidence interval [95% CI], 14-26%). In the group who had received > or = 3 prior regimens, a total of 6 partial responses were observed, for an objective response rate of 18% (95% CI, 12-23%). The median response duration was 8.2 months (range, 2.7-10.1 months) for the group who had received 2 prior regimens and 5.8 months (range, 2.1-9.5 months) for patients who received > or = 3 prior regimens. Responses were noted in patients with anthracycline-resistant tumors.

CONCLUSIONS

Paclitaxel was active in heavily pretreated patients with metastatic breast carcinoma, including anthracycline-resistant breast carcinoma.

Randomized trial of high-dose chemotherapy and blood cell autografts for high-risk primary breast carcinoma

BACKGROUND

Uncontrolled studies have reported encouraging outcomes for patients with high-risk primary breast cancer treated with high-dose chemotherapy and autologous hematopoietic stem cell support. We conducted a prospective randomized trial to compare standard-dose chemotherapy with the same therapy followed by high-dose chemotherapy.

PATIENTS AND METHODS

Patients with 10 or more positive axillary lymph nodes after primary breast surgery or patients with four or more positive lymph nodes after four cycles of primary (neoadjuvant) chemotherapy were eligible. All patients were to receive eight cycles of 5-fluorouracil, doxorubicin (Adriamycin), and cyclophosphamide (FAC). Patients were stratified by stage and randomly assigned to receive two cycles of high-dose cyclophosphamide, etoposide, and cisplatin with autologous hematopoietic stem cell support or no additional chemotherapy. Tamoxifen was planned for postmenopausal patients with estrogen receptor-positive tumors and chest wall radiotherapy was planned for all. All P values are from two-sided tests.

RESULTS

Seventy-eight patients (48 after primary surgery and 30 after primary chemotherapy) were registered. Thirty-nine patients were randomly assigned to FAC and 39 to FAC followed by high-dose chemotherapy. After a median follow-up of 6.5 years, there have been 41 relapses. In intention-to-treat analyses, estimated 3-year relapse-free survival rates were 62% and 48% for FAC and FAC/high-dose chemotherapy, respectively (P =.35), and 3-year survival rates were 77% and 58%, respectively (P =.23). Overall, there was greater and more frequent morbidity associated with high-dose chemotherapy than with FAC; there was one septic death associated with high-dose chemotherapy.

CONCLUSIONS

No relapse-free or overall survival advantage was associated with the use of high-dose chemotherapy, and morbidity was increased with its use. Thus, high-dose chemotherapy is not indicated outside a clinical trial.

Continuous-infusion high-dose leucovorin with 5-fluorouracil and cisplatin for relapsed metastatic breast cancer: a phase II study

Twelve women with metastatic breast cancer were treated with continuous infusion high dose leucovorin, 5-fluorouracil and cisplatin. Toxicity was severe although the dose was lower than previously described for the treatment of other cancers, and there was little anti-tumor activity. Many other regimens are more effective and less toxic.

Paclitaxel by 24-hour infusion with doxorubicin by 48-hour infusion as initial therapy for metastatic breast cancer: phase I results

PURPOSE

We and others have demonstrated the antineoplastic efficacy of paclitaxel as a single agent in metastatic breast cancer. We performed this phase I trial to evaluate the combination of paclitaxel with doxorubicin.

PATIENTS AND METHODS

Eligible patients had measurable or evaluable metastatic breast cancer for which this was the initial cytotoxic treatment. They may have received adjuvant chemotherapy with other drugs. The study had four parts. In part 1, the patients received paclitaxel by 24-hour infusion followed by doxorubicin by 48-hour infusion. The paclitaxel dose was to be escalated from a starting dose of 125 mg/m2, and the doxorubicin dose was to remain constant at 60 mg/m2 with treatment repeated every three weeks. The results of part 1 prompted part 2 which was a study of the reverse sequence. Part 3 was a formal study of pharmacology and has been reported (J Clin Oncol 14: 2713-21, 1996). In part 4, patients received doxorubicin 50 mg/m2 by bolus followed by paclitaxel 150 mg/m2 by 24-hour infusion for courses 1 and 2. In all subsequent courses doxorubicin was administered by 48-hour infusion. All patients in all four parts of the study had baseline cardiac scans. All patients received standard premedication for paclitaxel.

RESULTS

Forty-eight patients were treated in all four parts of the study. In part 1 (10 patients), the maximum tolerated dose (MTD) was paclitaxel 125 mg/m2/24 hours followed by doxorubicin 48 mg/m2/48 hours as defined by dose-limiting mucositis and neutropenic fever which occurred at the starting dose. For part 2 (21 patients), the MTD was doxorubicin 60 mg/m2/48 hours followed by paclitaxel 160 mg/m2/24 hours. In part 4 (seven patients), the MTD was doxorubicin 50 mg/m2/bolus followed by paclitaxel 135 mg/m2/24 hours. In parts 2 and 4, the dose-limiting toxic effect was neutropenia. Of the entire cohort of 48 patients, seven (15%) had a complete response (one persists at five years without intervening therapy), 26 (54%) had a partial response for an objective response rate of 69% (95% confidence interval (95% CI): 54%-81%). The median follow-up of all living patients is 38+ months (range 20+ to 62+); the median response duration is seven months (range 2-33.7+); the median overall survival is 20.5 months (range 5-54+). The median time to progression is 9.6 months (range 1-33.7+ months). Two patients developed congestive heart failure, one at 24 months after her final dose of doxorubicin which amounted to a cumulative lifetime total doxorubicin dose of 870 mg/m2, one after a total of 660 mg/m2. In both, cardiac symptoms were controlled with medications.

CONCLUSIONS

The combination of paclitaxel/24 hours with doxorubicin/48 hours is an effective antineoplastic treatment for metastatic breast cancer. However, the incidence of complete response, the median overall survival, and time to progression were not greater than for standard doxorubicin-based combinations. Additionally, a sequence-dependent interaction between paclitaxel and doxorubicin, given in the schedule described here, was defined. Other strategies and schedules should be evaluated to maximize the antineoplastic efficacy of these two potent agents.

Phase I/II trial of high dose mitoxantrone in metastatic breast cancer: the M.D. Anderson Cancer Center experience

Anthracyclines are among the most active agents in metastatic breast cancer. Mitoxantrone demonstrated a different toxicity profile when compared to doxorubicin. We performed a phase I/II study of single-agent high-dose mitoxantrone therapy for advanced breast cancer. Nineteen patients who had a diagnosis of metastatic breast cancer received treatment at the M.D. Anderson Cancer Center between June 1986 and December 1987. The patients received escalating doses of mitoxantrone until a maximum tolerated dose (MTD), defined as grade 3 or 4 nonhematologic toxicity or infection, was obtained. The starting dose of 25 mg/m2, given by short intravenous infusion, was escalated by 25% in each five-patient cohort if each patient in the previous cohort tolerated the initial course and 2 or fewer patients reached the MTD. The median cumulative dose of mitoxantrone was 93 mg/m2 (range, 25-205) and the maximum single dose was 39 mg/m2. Myelosuppression was the dose limiting toxicity. The median duration of granulocyte count < or = 250/microl was 5-7 days. Four patients (22%) had infections that required hospitalization, 3 patients (17%) had cardiac toxicity. One patient (6%) achieved a complete response, and 3 (17%) had a partial response, with an overall response rate of 22.3%. No apparent dose-response relationship was observed in our study. The mitoxantrone dosage recommended for phase II studies is 25 mg/m2 every 3-4 weeks. We conclude that high-dose mitoxantrone therapy for metastatic breast cancer was relatively well tolerated but was not associated with a higher response rate than that of standard dose mitoxantrone.

Management of breast cancer during pregnancy using a standardized protocol

PURPOSE

No standardized therapeutic interventions have been reported for patients diagnosed with breast cancer during pregnancy. Of the potential interventions, none have been prospectively evaluated for treatment efficacy in the mother or safety for the fetus. We present our experience with the use of combination chemotherapy for breast cancer during pregnancy.

PATIENTS AND METHODS

During the past 8 years, 24 pregnant patients with primary or recurrent cancer of the breast were managed by outpatient chemotherapy, surgery, or surgery plus radiation therapy, as clinically indicated. The chemotherapy included fluorouracil (1,000 mg/m2), doxorubicin (50 mg/m2), and cyclophosphamide (500 mg/m2), administered every 3 to 4 weeks after the first trimester of pregnancy. Care was provided by medical oncologists, breast surgeons, and perinatal obstetricians.

RESULTS

Modified radical mastectomy was performed in 18 of the 22 patients, and two patients were treated with segmental mastectomy with postpartum radiation therapy. This group included patients in all trimesters of pregnancy. The patients received a median of four cycles of combination chemotherapy during pregnancy. No antepartum complications temporally attributable to systemic therapy were noted. The mean gestational age at delivery was 38 weeks. Apgar scores, birthweights, and immediate postpartum health were reported to be normal for all of the children.

CONCLUSION

Breast cancer can be treated with chemotherapy during the second and third trimesters of pregnancy with minimal complications of labor and delivery.

Phase II study of mitoxantrone by 14-day continuous infusion with granulocyte colony-stimulating factor (GCSF) support in patients with metastatic breast cancer and limited prior therapy

PURPOSE

Early phase II evaluation of intravenous bolus mitoxantrone indicated objective response rates of 17 36% in patients with metastatic breast cancer. Subsequently, it has been suggested that continuous infusion may be the optimal way to administer this drug in order to achieve maximal cytotoxic effect with minimal toxicity. We present the results of a phase II study that evaluated the efficacy and side effects of mitoxantrone administered at the maximally tolerated dose by continuous infusion in patients with metastatic breast cancer.

METHODS

This study included 16 patients with metastatic breast cancer and limited previous therapy for their metastatic disease. Mitoxantrone, 1.5 mg/m2 per day, was given by continuous intravenous infusion for 14 consecutive days repeated every 21 days with concomitant granulocyte colony-stimulating factor support. Dose escalation was allowed.

RESULTS

No complete tumor response was seen. Two patients (13%, CI 0-29%) had a partial response, nine patients (56%) had progressive disease and the remaining five patients (31%) had stable disease on therapy. The major dose-limiting side effect was myelotoxicity. Two of the 16 patients (13%) experienced asymptomatic cardiotoxicity that required discontinuation of therapy.

CONCLUSIONS

Our results indicate limited antitumor activity and significant toxicity of mitoxantrone given by continuous infusion as second-line chemotherapy for metastatic breast cancer. The objective response rate documented in this study is inferior to response rates reported with other second-line regimens, particularly the taxanes, now available for this patient population.

A phase II study of docetaxel in patients with paclitaxel-resistant metastatic breast cancer

PURPOSE

To evaluate the efficacy and safety of docetaxel in patients with paclitaxel-resistant metastatic breast cancer (MBC).

PATIENTS AND METHODS

Docetaxel (100 mg/m2) was administered every 3 weeks to 46 patients registered at four centers. Patients had previously received < or = two chemotherapy regimens for MBC. All patients had progressive disease while receiving paclitaxel therapy. Treatment was repeated until there was evidence of disease progression or for a maximum of three cycles after best response.

RESULTS

Objective responses were seen in eight of 44 assessable patients (18.1%; 95% confidence interval [CI], 6.7% to 29.5%). Seven patients had partial responses and one patient responded completely. Response rates were not significantly different by previously received paclitaxel dose or resistance. No responses were seen in 12 patients who had previously received paclitaxel by 24-hour infusion, but the response rate in 32 patients who had received paclitaxel by 1- to 3-hour infusion was 25%. The median response duration was 29 weeks and the median time to disease progression was 10 weeks. Median survival was 10.5 months. Clinically significant (severe) adverse events included neutropenic fever (24% of patients), asthenia (22%), infection (13%), stomatitis (9%), neurosensory changes (7%), myalgia (7%), and diarrhea (7%).

CONCLUSION

Docetaxel is active in patients with paclitaxel-resistant breast cancer, particularly in those who failed to respond to brief infusions of paclitaxel. Response rates were comparable to or better than those seen with other therapies for patients with paclitaxel-resistant MBC. This confirms preclinical studies, which indicated only partial cross-resistance between paclitaxel and docetaxel.

Phase II study of ifosfamide and mesna in patients with metastatic breast cancer

The aim of this paper is to evaluate the activity of ifosfamide in previously treated patients with metastatic breast cancer. From June 1991 through November 1992, 29 patients with metastatic breast cancer were treated with single-agent ifosfamide, 2 g/m2 intravenously daily for 5 days, with mesna support. All patients had previously received chemotherapy; all but one had previously received cyclophosphamide. The ifosfamide-mesna regimen was the first-line metastatic regimen in 15 patients, the second-line metastatic regimen in 13 patients, and the third-line metastatic regimen in one patient. Two partial remissions (7%) were observed; both occurred in the first-line metastatic group. The partial remissions were noted in patients who had completed adjuvant cyclophosphamide therapy 60 and 91 months earlier. Both responses were seen in lung metastases. The response durations were 5 and 8 months on continued therapy. The main adverse effects were granulocytopenia, fatigue, nausea, vomiting, and stomatitis. At the dose used in this study, ifosfamide and mesna given without growth-factor support resulted in significant myelosuppression and produced only two partial remissions (7%) in 29 patients. Further study of ifosfamide as an isolated agent in previously treated patients is not warranted.

Secondary drug resistance in breast cancer: failure to reverse with oral nifedipine

We tested the efficacy of nifedipine to reverse acquired resistance to chemotherapy regimens containing doxorubicin or vinblastine or both in 12 patients with metastatic breast cancer. All patients had been receiving one or both of these drugs, had had a prior partial response (median duration 5 months, range 2-10) and subsequently progressed. Immediately after drug resistance was documented by tumor progression, eligible patients with measurable or evaluable disease were treated with nifedipine beginning 3 days before restarting the same chemotherapy. The initial dose of nifedipine was 20 mg TID, escalating daily to 40 mg TID on day 3 if the patient had no serious side effects. Nifedipine was continued at the highest tolerable dose during and for 2 days after completion of the chemotherapy. Most patients had < or = 2 prior chemotherapy regimens and a median Zubrod performance status of 1. Twelve patients received a total of 23 courses preceded by nifedipine. No objective tumor responses were observed. The expected toxic effects attributable to nifedipine occurred, but nifedipine did not increase the toxicity caused by the chemotherapy. Nifedipine, given in this dose and schedule, did not reverse acquired drug resistance in patients with breast cancer.

Prospective assessment of cardiac toxicity during a randomized phase II trial of doxorubicin and paclitaxel in metastatic breast cancer

Since both doxorubicin and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) have substantial antitumor activity in advanced breast cancer, the combination of these two agents was a logical extension of the clinical development of paclitaxel. Early attempts used long infusions of both drugs, limiting the dose of both agents because of limiting gastrointestinal and myelosuppressive toxicity. Bolus doxorubicin combined with 3-hour infusion paclitaxel was reported to have dramatic antitumor activity, but clinically relevant cardiac toxicity in up to 20% of patients in two recent reports. In our current study the same schedules and doses of administration were used, limiting the total doxorubicin dose of 360 mg/m2. In-depth monitoring of cardiac function with noninvasive tests and endomyocardial biopsy were performed. Preliminary results suggest that, at these doses and schedule, the two-drug combination is safe, without unexpected toxicity. Limiting doxorubicin dose to 360 mg/m2 limits cardiac toxicity to levels expected from single-agent doxorubicin at similar cumulative doses.

Combination chemotherapy with paclitaxel and doxorubicin for metastatic breast cancer

The development of anthracycline/paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) combinations has gone through several phases or generations. The first dose escalation studies used prolonged infusions of doxorubicin (48 to 72 hours) and paclitaxel (24 hours). Myelosuppression, mucositis, and neutropenic fever were dose limiting, and a sequence-dependent interaction was noted. In a second phase, doxorubicin was administered by bolus, without changing the schedule of the taxane. More recently, bolus doxorubicin was combined with 3-hour paclitaxel infusions. Higher doses of both agents were administered in this latter schedule, with higher overall response rates reported. Excessive cardiac toxicity was reported with the initial trials that used this schedule. Confirmatory studies are under way pursuing several alternatives to reduce the risk of cardiac toxicity; these include limiting the cumulative dose of doxorubicin, inserting an interval between the administration of the two drugs, and adding a cardioprotective agent to the combination. The high degree of antitumor activity of this combination is quite encouraging, and additional evaluation of this regimen in controlled trials is warranted in metastatic and high-risk primary breast cancer.

The University of Texas M.D. Anderson Cancer Center experience with paclitaxel in breast cancer

The first phase II study of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in breast cancer was completed at M.D. Anderson Cancer Center, and included 25 patients with metastatic breast cancer who had been previously treated with one chemotherapy regimen. Fourteen of these patients achieved a major objective response; the median response duration was 9 months, and the median survival time, 20 months. Additional trials showed that paclitaxel maintained its antitumor efficacy in patients with two and three prior chemotherapy regimens, including patients with anthracycline-resistant breast cancer. Combination therapy with doxorubicin showed that this combination was effective, although with the long infusion duration used for both agents, sequence-dependent toxic interactions were encountered. In combination with vinorelbine, dose-limiting toxicity included neutropenic fever and neuropathy. High-dose single-agent paclitaxel is currently being explored in the management of inflammatory breast cancer and as part of neoadjuvant chemotherapy for stages II and III operable disease.

Optimal dosing of paclitaxel and doxorubicin in metastatic breast cancer

The taxanes and the anthracyclines are clearly the most effective agents available to treat breast cancer. Developing combinations based on these two drug types is a logical direction in clinical investigation. The doxorubicin/paclitaxel doublet has been evaluated by several groups using a variety of doses and schedules of administration. Preliminary data from single-arm phase I/II trials suggest that when administered as consecutive short infusions, these two drugs produce a high overall response rate with tolerable toxicity. Whether the complete remission rates, response durations, and survival rates achieved with this combination are equally promising awaits additional confirmatory trials, including ongoing randomized trials that compare this doublet with doxorubicin/cyclophosphamide. The apparent increase in the incidence of clinical congestive heart failure (approximately 20%) observed in the Milan and Copenhagen trials is a potential limitation of the long-term administration of this combination. Limiting the cumulative dose of doxorubicin, adding cardioprotectors, and substituting less cardiotoxic anthracylines (ie, epirubicin) represent investigational efforts to minimize cardiac toxicity.

Combined-modality treatment of inflammatory breast carcinoma: twenty years of experience at M. D. Anderson Cancer Center

PURPOSE

To review the 20 years of experience at M. D. Anderson Cancer Center with a combined-modality approach against inflammatory breast carcinoma.

PATIENTS AND METHODS

A total of 178 patients with inflammatory breast carcinoma were treated in the past 20 years at M. D. Anderson Cancer Center by a combined-modality approach under four different protocols. Each protocol included induction chemotherapy, then local therapy (radiotherapy or mastectomy), then adjuvant chemotherapy, and, if mastectomy was performed, adjuvant radiotherapy. Chemotherapy consisted of 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) with or without vincristine and prednisone (VP). In protocol D, patients received an alternate adjuvant chemotherapy regimen, methotrexate and vinblastine (MV), if they did not have a complete response (CR) to induction chemotherapy.

RESULTS

The median follow-up of live patients in group A was 215 months, in group B 186 months, in group C 116 months, and in group D 45 months. An estimated 28% of patients were currently free of disease beyond 15 years. At the time of analysis, 50 patients were alive without any evidence of disease. A further 12 patients died of intercurrent illness, and 15 patients were followed beyond 10 years without recurrence of disease. Among initial recurrence, 20% of patients had local failure, 39% systemic failure, and 9% CNS recurrence. Initial response to induction chemotherapy was an important prognostic factor. Disease-free survival (DFS) at 15 years was 44% in patients who had a CR to induction chemotherapy, 31% in those who had a partial response (PR), and 7% in those who had less than a PR. There was no improvement in overall survival (OS) or DFS among patients who underwent alternate chemotherapy (MV) compared with those who did not. Using surgery and radiotherapy as opposed to radiotherapy alone as local therapy did not have an impact on the DFS or OS rate.

CONCLUSION

These long-term follow-up data show that with a combined-modality approach a significant fraction of patients (28%) remained free of disease beyond 15 years. In contrast, single-modality treatments yielded a DFS of less than 5%. Thus, using combined-modality treatment (chemotherapy, then mastectomy, then chemotherapy and radiotherapy) is recommended as a standard of care for inflammatory breast carcinoma.

Paclitaxel combination therapy in the treatment of metastatic breast cancer: a review

Combinations of active antineoplastic agents have been the most effective treatment for metastatic breast cancer. Criteria for an effective combination include use of drugs with different mechanisms of action, nonoverlapping toxic effects, and synergistic, or at least additive, antitumor activity. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), with its unique mechanism of action, offers an excellent opportunity for development of effective combination therapy against breast cancer. However, a number of problems have hindered the rapid development of effective combinations. The most obvious problem is the lack of a defined optimal dose and schedule of administration. The second problem has been the demonstration of unexpected interactions between paclitaxel and the other component(s) of the combination, often resulting in unusual and serious toxic effects. This review will focus on the phase I and II trials of paclitaxel in combination with established antineoplastic drugs (except doxorubicin and congeners, which is covered elsewhere in this issue) for breast cancer: cisplatin, 5-fluorouracil with or without folinic acid, cyclophosphamide, radiation therapy, as well as novel investigational agents or strategies, edatrexate, monoclonal antibodies to oncogenes, growth factors, and gene therapy with insertion of multidrug resistance gene into blood stem cells. Combination therapy offers exciting possibilities of enhanced antitumor efficacy. However, given the unexpected and serious toxic effects observed, only proven combinations should be used outside the context of a clinical trial. Additionally, the burden of proof will be to show that these combinations have increased antitumor activity, decreased toxicity, or both compared with single-agent paclitaxel.

Sequence-dependent alteration of doxorubicin pharmacokinetics by paclitaxel in a phase I study of paclitaxel and doxorubicin in patients with metastatic breast cancer

PURPOSE

To determine whether a schedule-dependent interaction occurs when paclitaxel and doxorubicin are administered sequentially.

PATIENTS AND METHODS

Ten patients with metastatic breast cancer received paclitaxel 125 mg/m2 over 24 hours either immediately before or after doxorubicin 48 mg/m2 over 48 hours as the initial chemotherapy treatment. Two such courses were given, and the sequence of administration was reversed after course 1. In cohort 1, paclitaxel preceded doxorubicin for course 1. In cohort 2, doxorubicin preceded paclitaxel for course 1. Doxorubicin levels were measured serially during the infusion and for 24 hours following it. Patients were assessed clinically for the occurrence of stomatitis and infection and granulocyte counts were measured twice weekly.

RESULTS

Eight patients had complete pharmacokinetic sampling for both courses. The mean end-of-infusion plasma doxorubicin concentrations (Cmax) were 70% higher in the paclitaxel-doxorubicin sequence compared with the reverse sequence (45 +/- 8 ng/mL v 26 +/- 5 ng/ mL). The mean doxorubicin clearance was 32% lower in the paclitaxel-doxorubicin sequence (34.3 +/- 10.3 L/h v 51.6 +/- 16.1 L/h, P < .01). Clinically, hematologic and mucosal toxic effects were worse in the paclitaxel-doxorubicin sequence. The median absolute granulocyte count was 0.2/microL in the paclitaxel-doxorubicin sequence and 1.3/microL in the doxorubicin-paclitaxel sequence. Seven of 10 patients who received the paclitaxel-doxorubicin sequence had grade 2 (n = 4) or 3 (n = 3) stomatitis, while only one of 10 patients who received the doxorubicin-paclitaxel sequence had grade 2 stomatitis and none had grade 3.

CONCLUSION

When paclitaxel by 24-hour infusion precedes doxorubicin by 48-hour infusion, doxorubicin clearance is reduced by nearly one third, which results in grade 2 and 3 stomatitis. To prevent this effect when paclitaxel (by 24-hour infusion) and doxorubicin are administered sequentially, doxorubicin should be given first. The mechanisms for this effect are under investigation.

Paclitaxel combination therapy in the treatment of metastatic breast cancer

After the single-agent activity of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) was confirmed, trials to develop a synergistic combination began. Doxorubicin, the most active agent for breast cancer, was studied first. As paclitaxel became more available, other combinations, including high-dose regimens and adjuvant therapies, have been studied. No optimal combination regimen has been defined. Recent and/or ongoing trials are looking at paclitaxel in combination with cisplatin, cyclophosphamide, 5-fluorouracil/ folinic acid, and mitoxantrone combinations, as well as with high-dose regimens and as adjuvant therapy. This review describes a plethora of combination studies finally under way to better define the optimal use of paclitaxel in breast cancer therapies, both as adjuvant treatment and for metastatic disease. Because of the unpredictable nature of drug interactions related to schedule and sequence, ad hoc combinations should not be undertaken outside the context of a well-designed trial.

A phase II study of CI-973 [SP-4-3(R)]-1,1-cyclobutane-dicarboxylato (2-)] (2-methyl-1,4-butanediamine-N, N') platinum in patients with refractory advanced breast cancer

CI-973 is a water-soluble platinum diamine complex whose antitumor activity is greater than that of cisplatin in some murine tumors. It has shown activity against cisplatin-resistant tumors. This phase II trial had the objectives of determining the therapeutic efficacy of CI-973 in patients with metastatic breast cancer who had been treated with one prior chemotherapy regimen, and of further defining the toxicity of the agent and the reversibility of its toxicity. CI-973 was administered as an intravenous infusion over 30 min with no prehydration or antiemetic programs. Treatment cycles were repeated at 21-day intervals. Patients with histologically confirmed metastatic breast cancer, measurable disease, and good performance status who had received only one prior chemotherapy regimen for metastatic disease were eligible for treatment. Adequate hematologic, renal, and hepatic function were required. A total of 26 patients received a median of two courses of CI-973 (range, 1-18 courses). Hematologic toxicity was severe: nearly all patients experienced granulocytopenia with granulocyte counts of 0 at all dose levels. Nevertheless, neutropenic fever and documented systemic infection were uncommon, and there were no hospitalizations for neutropenic fever or infection. Visceral disease dominated in this patient group. Of the 26 patients, 14 had visceral disease, 6 had bone or bone marrow disease, and 6 had skin, soft-tissue, or lymph-node disease. Of the 26 patients treated, 25 were evaluable for response. There were two partial remissions, one in liver and one in bone, and three minor responses, for a response rate of 8%. Nonhematologic toxic effects were mild and consisted of nausea and vomiting, fatigue, minimum peripheral paresthesia, and hypomagnesemia. Further study of CI-973 at the dose and schedule used in this study is not warranted. Because this agent had no significant extramedullary toxicity, intensification of the dose of CI-973 with concomitant administration of colony-stimulating factors has the potential to improve response in this patient population.

Single-agent paclitaxel for the treatment of breast cancer: an overview

Initial trials using a 24-hour intravenous infusion of 250 mg/m2 paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in the treatment of breast cancer yielded objective regression in 56% to 62% of patients with no or only one prior chemotherapy regimen. Tolerance to single-agent paclitaxel seemed acceptable, but after multiple cycles, peripheral neuropathy developed in a significant fraction of patients. Lower doses and, more recently, the 3-hour infusion schedule still produced objective responses, albeit lower, in the range of 20% to 35%. It became apparent that toxicity was dose and schedule dependent, and likely there was a dose-response correlation. A 96-hour infusion schedule yielded a maximum tolerated dose of 140 mg/m2, and no hypersensitivity reactions despite omission of the standard triple-drug premedication. More recently, a 1-hour infusion schedule (plus standard triple-drug premedication) was well tolerated, with activity in both lung and breast cancer similar to that observed after a 3-hour infusion treatment. Paclitaxel retained therapeutic activity, even among patients with anthracycline-refractory breast cancer, in clinical trials using the 3-, 24-, and 96-hour infusion of paclitaxel. Current ongoing trials will explore the range of paclitaxel activity of various doses and by alternative schedules, both as second-line therapy and in the adjuvant and neoadjuvant setting.

Phase II trial of docetaxel: a new, highly effective antineoplastic agent in the management of patients with anthracycline-resistant metastatic breast cancer

PURPOSE

To determine the efficacy (objective response rate and duration of response and survival) and toxicity of docetaxel in patients with strictly defined anthracycline-resistant metastatic breast cancer (MBC).

PATIENTS AND METHODS

Thirty-five patients with bidimensionally measurable MBC who had progressive disease while receiving anthracycline-containing chemotherapy were registered onto the phase II trial. Docetaxel was administered at a dose of 100 mg/m2 over 1 hour every 21 days.

RESULTS

Thirty-four patients were assessable for disease response; 18 (53%; 95% confidence interval [CI], 35% to 70%) achieved a partial response. The median times to disease progression and survival duration were 7.5 and 13.5 months, respectively, for responding patients. The median overall survival duration was 9 months. Two hundred eight cycles (median, five) of docetaxel were administered. Neutropenia with less than 500 cells/microL developed in 31 of 35 patients; it was complicated by fever in 30 (14%) of 208 cycles and in 18 (51%) of 35 patients, including one treatment-related death. Fluid retention was seen in 15 (43%) of 35 patients, including pleural effusions in 11 patients (31%). Moderate skin toxicity, asthenia, and myalgia were observed in 16%, 58%, and 37% of cycles, respectively.

CONCLUSION

Docetaxel has the highest reported antitumor activity in anthracycline-resistant MBC. High objective response rates were seen in patients with visceral-dominant involvement, multiple metastatic sites, or extensive previous therapy. Docetaxel is associated with severe but reversible neutropenia, asthenia, and cumulative dose-related fluid retention. Dexamethasone decreased the frequency and severity of skin toxicity and appeared to ameliorate fluid retention.

Update: the M.D. Anderson Cancer Center experience with paclitaxel in the management of breast carcinoma

The first of three trials at M.D. Anderson Cancer Center investigating paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in metastatic breast cancer was a phase II study involving 25 patients (297 courses) previously treated with only one chemotherapy regimen; the patients received paclitaxel 250 mg/m2 infused over 24 hours without granulocyte colony-stimulating factor (G-CSF). Complete (12%) and partial responses (44%) led to median durations of response and survival of 9 and 21 months, respectively. The median paclitaxel dose was 200 mg/m2. Despite profound neutropenia (median granulocyte count of 0.3 cells x 10(9)/L for the first three courses), infection occurred in 42% of patients but only 6% of courses. In a phase I trial of paclitaxel 125 mg/m2 over 24 hours followed by doxorubicin 60 mg/m2 using G-CSF at 5 micrograms/kg days 5 through 19, dose-limiting mucositis with neutropenic fever occurred at the starting dose, so the maximum tolerated dose was one dose lower: paclitaxel 125 mg/m2 (over 24 hours) followed by doxorubicin 48 mg/m2 over 48 hours. Among 10 patients, there was one complete response and seven partial responses (overall response, 80%). Suspecting a schedule-dependent interaction between drugs, a phase I trial of the reverse sequence yielded a maximum tolerated dose, defined by neutropenic fever without mucositis, of doxorubicin 60 mg/m2 (over 48 hours) followed by paclitaxel 150 mg/m2 (over 24 hours) in 21 patients. A pharmacokinetic study in which the sequence of administration of paclitaxel over 24 hours and doxorubicin over 48 hours was alternated in courses 1 and 2 indicated that when paclitaxel by 24-hour infusion is given first, doxorubicin plasma levels at the end of infusion were an average 70% higher and doxorubicin clearance was reduced approximately 30% compared with the reverse sequence. Similarly, the incidence of grade 2 or 3 mucositis was 70% with the paclitaxel/doxorubicin sequence versus only 10% with the reverse sequence. We concluded that paclitaxel slows doxorubicin metabolism and that when used together in this schedule, doxorubicin should precede paclitaxel. In the third trial paclitaxel without G-CSF was administered to two groups of heavily pretreated patients: (1) those with only two prior chemotherapy regimens (inclusive of adjuvant therapy) received paclitaxel 175 mg/m2 over 24 hours and (2) those with three or more prior regimens received paclitaxel 150 mg/m2 over 24 hours. Response rates in both regimens were approximately 20%. We conclude that paclitaxel has significant antitumor activity in metastatic breast cancer, especially in patients with limited prior therapy, without need for G-CSF.(ABSTRACT TRUNCATED AT 400 WORDS)