Phosphoproteomic analysis of neoadjuvant breast cancer suggests that increased sensitivity to paclitaxel is driven by CDK4 and filamin A

Precision oncology research is challenging outside the contexts of oncogenic addiction and/or targeted therapies. We previously showed that phosphoproteomics is a powerful approach to reveal patient subsets of interest characterized by the activity of a few kinases where the underlying genomics is complex. Here, we conduct a phosphoproteomic screening of samples from HER2-negative female breast cancer receiving neoadjuvant paclitaxel (N = 130), aiming to find candidate biomarkers of paclitaxel sensitivity. Filtering 11 candidate biomarkers through 2 independent patient sets (N = 218) allowed the identification of a subgroup of patients characterized by high levels of CDK4 and filamin-A who had a 90% chance of achieving a pCR in response to paclitaxel. Mechanistically, CDK4 regulates filamin-A transcription, which in turn forms a complex with tubulin and CLIP-170, which elicits increased binding of paclitaxel to microtubules, microtubule acetylation and stabilization, and mitotic catastrophe. Thus, phosphoproteomics allows the identification of explainable factors for predicting response to paclitaxel.

Evaluating the addition of bevacizumab to endocrine therapy as first-line treatment for hormone receptor-positive metastatic breast cancer: a pooled analysis from the LEA (GEICAM/2006-11_GBG51) and CALGB 40503 (Alliance) trials

BACKGROUND

Randomised trials comparing the efficacy of standard endocrine therapy (ET) versus experimental ET + bevacizumab (Bev) in 1st line hormone receptor-positive patients with metastatic breast cancer have thus far shown conflicting results.

PATIENTS AND METHODS

We pooled data from two similar phase III randomised trials of ET ± Bev (LEA and Cancer and Leukemia Group B 40503) to increase precision in estimating treatment effect. Primary end-point was progression-free survival (PFS). Secondary end-points were overall survival (OS), objective response rate (ORR), clinical benefit rate (CBR) and safety. Exploratory analyses were performed within subgroups defined by patients with recurrent disease, de novo disease, prior endocrine sensitivity or resistance and reported grades III-IV hypertension and proteinuria.

RESULTS

The pooled sample consisted of 749 patients randomised to ET or ET + Bev. Median PFS was 14.3 months for ET versus 19 months for ET + Bev (unadjusted hazard ratio [HR] 0.77; 95% confidence interval [CI] 0.66-0.91; p < 0.01). ORR and CBR with ET and ET + Bev were 40 versus 61% (p < 0.01) and 64 versus 77% (p < 0.01), respectively. There was no difference in OS (HR 0.96; 95% CI 0.77-1.18; p = 0.68). PFS was superior for ET + Bev for endocrine-sensitive patients (HR 0.68; 95% CI 0.53-0.89; p = 0.004). Grade III-IV hypertension (2.2 versus 20.1%), proteinuria (0 versus 9.3%), cardiovascular (0.5 versus 4.2%) and liver events (0 versus 2.9%) were significantly higher for ET + Bev (all p < 0.01). Hypertension and proteinuria were not predictors of efficacy (interaction test p = 0.33).

CONCLUSION

The addition of Bev to ET increased PFS overall and in endocrine-sensitive patients but not OS at the expense of significant additional toxicity.

TRIALS REGISTRATION

ClinicalTrial.Gov NCT00545077 and NCT00601900.

Abstract PD2-09: High-throughput phosphoproteomics (HTPS) in neoadjuvant (NEO) breast cancer (BC) reveals clusters of extreme sensitivity to paclitaxel (T)

Background: NGS has elucidated the mutational landscape in BC. However, the correlation between mutational landscapes and complex phenotypic traits such as drug response is yet unclear. The genomic and transcriptomic aberrations coalesce into a diverse number of phosphorylation-driven patterns of activation of the proteome. These patterns are and associated to clinical outcomes of interest. The specific nature of the phosphopeptides in a profile versus another can be driven by a small number of activated kinases. In the past we relied on mass-spectrometry-based HTPS to build a kinase-based classification of triple-negative breast cancer (TNBC, Nat. Comms, in press), which is more parsimonious than gene-centered classifications and uncovers new actionable targets. We implemented this methodology to find predictors of response to T in early BC.

Methods: Training set: fresh baseline and day+15 tumor biopsies form a trial in NEO HER2-negative BC (N=139) that randomized patients to T (80 mg/m2 weekly x12) plus placebo or nintedanib (150 mg b.i.d) were processed with a hybrid ion trap-orbitrap mass spectrometer after TiO2 phospho-enrichment. Phosphoprofiles were compared pair-wise according to the following factors: day 0 versus day + 15, standard versus experimental arm, pathologic response Symmans/Pusztai (Symmans) 0/1 vs 2/3. Kinases driving each phosphoprofile were solved by an in silico algorithm termed kinase-set enrichment analysis (KSEAS). Validation set: an in-house designed and previously validated mass-spectrometry-to-immunohistochemistry translation algorithm was used to validate the kinases enriched in the profiles from the baseline samples of patients achieving Symmans 0/1 (pCR) or Symmans=3 in the training set. Probes against those kinases were validated in an independent dataset of 160 HER2-negative patients receiving NEO T followed by AC. H-score of each activated kinase was divided in quartiles (Q1 to Q4), and upper-quartiles (Q1) of each kinase were tested in a multivariate logistic regression model to predict pCR adjusted by T, N, age, G, ER/PR and Ki67.

Results: &gt;2.5 millions of spectra were captured, identifying &gt;35000 unique phosphopeptides mapping to &gt;2500 unique proteins per sample. Training set: KSEAS revealed that a high activity of CDK4 and pP70S6K drove the baseline phosphoprofiles of the patients obtaining pCR in the T arm, whereas pSTAT3, pSrc and BARD drove that of the patients achieving Symmans= 3. In the validation set, H-score cut-offs for Q1 were 1.21, 0.69, 0.79, 1.64 and 1.54 for pP70S6K, CDK4, pSTAT3, pSrc and BARD. TNBC patients with Q1 pP70S6K or Q1 CDK4 achieved pCR in 100% of the cases (versus 45% in Q2-4). In the HR+ cases, the pCR rate for Q1 patients was 50% and 61% respectively. In the multivariate model (all patients), having Q1 pP70S6K or CDK4 multiplied by 2.3- and 3.6-fold, respectively, the probability of achieving pCR (P&lt;0.05). Regarding Symmans=3, BARD and pSTAT3 lost significance in the validation but not pSrc (2.5-fold less probability of pCR, P&lt;0.005).

Conclusions: HTPS is a useful tool to find associations with complex traits. TNBC and HR+ patients with high pP70S6K or CDK4 receiving NEO T-based chemotherapy achieve very high rates of pCR.

Citation Format: Quintela-Fandino M, Lluch A, Manso L, Calvo I, Cortes J, Garcia-Saenz JA, Zagorac I, Tapial-Martinez P, Gomez-Lopez G, Fustero C, Muñoz J, Gonzalez-Cortijo L, Mouron S. High-throughput phosphoproteomics (HTPS) in neoadjuvant (NEO) breast cancer (BC) reveals clusters of extreme sensitivity to paclitaxel (T) [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 PD2-09.

Metastatic or locally advanced breast cancer patients: towards an expert consensus on nab-paclitaxel treatment in HER2-negative tumours-the MACBETH project

INTRODUCTION

Despite the large use of nab-paclitaxel as a treatment option in metastatic breast cancer (MBC) across different countries, no definitive data are available in particular clinical situations.

AREAS COVERED

Efficacy, safety and schedule issues concerning available literature on nab-paclitaxel in advanced breast cancer and in specific subgroups of patients have been discussed and voted during an International Expert Meeting. Ten expert specialists in oncology, with extensive clinical experience on Nab-P and publications in the field of MBC have been identified. Six scientific areas of interest have been covered, generating 13 specific Statements for Nab-P, after literature review. For efficacy issues, a summary of research quality was performed adopting the GRADE algorithm for evidence scoring. The panel members were invited to express their opinion on the statements, in case of disagreement all the controversial opinions and the relative motivations have been made public.

EXPERT OPINION

Consensus was reached in 30.8% of the Nab-P statements, mainly those regarding safety issues, whereas ones regarding efficacy and schedule still remain controversial areas, requiring further data originated by the literature.

Abstract P4-21-05: Neoadjuvant non-pegylated liposomal doxorubicin plus paclitaxel, trastuzumab and pertuzumab in patients with HER2+ breast cancer – Final results of the SOLTI OPTI-HER HEART study

INTRODUCTION

Targeting HER2 by dual blockade with trastuzumab (T) and pertuzumab (P) in a taxane-based regimen is an active neoadjuvant treatment (NAT) of HER2+ early breast cancer (EBC). Addition of an anthracycline could further enhance this response, but potential cardiac toxicity is a concern. The Opti-HER HEART trial (NCT01669239) aims to optimize neoadjuvant treatment while minimizing cardiac risk, by combining T+P with a taxane and non-pegylated liposomal doxorubicin (NPLD).

MATERIAL AND METHODS

Phase II open-label, single-arm study of six 21-day cycles of NPLD (50mg/m2 D1), paclitaxel (80mg/m2 D1,8,15), T (4mg/kg C1D1, followed by 2mg/kg weekly), and P (840mg C1D1, followed by 420mg C2-6D1) as NAT for patients (pts) with stage II-IIIB HER2+ BC. Primary objective was to evaluate cardiac safety of the combination, measured by the incidence of type A (symptomatic congestive heart failure ) or type B [asymptomatic reduction of Left Ventricular Ejection Fraction (LVEF) value: ≥10% absolute decrease and LVEF&lt;50%, LVEF&lt;40% or any absolute decrease ≥20%] events, during NAT. Eighty-three pts were required to reject with 80% confidence the null hypothesis that the combination increases the incidence of cardiac events above the historical control of 18% (3% type A; 15% type B).

RESULTS

Between June 2013 and January 2015, 83 pts with HER2+ EBC (stage II 78%, stage III 22%) and adequate cardiac function (LVEF≥55%) were enrolled. Mean age was 50 years, N+ 47%, hormone receptor (HR) positive 71% and median baseline LVEF 66%. Eighty-five percent of pts completed 6 cycles of NAT, whereas 15% discontinued NAT due to toxicity. Adverse events (AEs) leading to dose adjustments/temporary interruptions and discontinuation of at least 1 drug occurred in 70% and 21% of pts, respectively. Primary objective was met with an incidence of cardiac events during NAT of 4% (95%CI 1-10, 3pts, all type B). Cardiac events until study completion (1 year) were 8% (all type B). All (but 2 cases with no follow-up data) were reversible and only 1 pt presented an asymptomatic LVEF&lt;40%. Neutropenia (45%) was the most frequent hematological toxicity (G3/4 34%; febrile neutropenia 6%), less frequent in the 71% of pts that received primary G-CSF prophylaxis (G3/4 25% vs. 67%). Common non-hematological toxicities were diarrhea (74%; G3 7%), asthenia (78%; G3 11%) and neurotoxicity (52%; G3/4 10%). Pathological complete response (pCR) in breast+axilla (ypT0/is ypN0) was 60% (87% in HR-) and 69% in breast (91% in HR-).

 TOTALHR-HR+% ypT0/is (95% CI)69 (58-79)91 (72-99)61 (47-74)% ypT0/is ypN0 (95% CI)60 (46-71)87 (66-97)50 (36-64)

CONCLUSIONS

The neoadjuvant combination of T+P, paclitaxel and NPLD does not increase the risk for cardiac events in HER2+ BC pts. Since cardiac toxicities may present later, long-term cardiac monitoring is essential. Efficacy in terms of pCR was remarkable, being higher to historical values of combinations with dual anti-HER2 blockade and one of the highest reported among HR-HER2+ BC. This regimen administered with primary G-CSF prophylaxis and cardiac function monitoring may be an effective and secure option for early and locally advanced HER2+ pts with good cardiac function.

Citation Format: Gavilá J, Perez-Garcia J, Calvo I, Ciruelos E, Muñoz M, Virizuela JA, Ruiz I, Andrés R, Morales S, Perelló A, Sánchez P, Garcia-Saenz JA, Quero Guillen JC, González-Santiago S, Garau Llinas I, González-Martín A, Cantos Sánchez de Ibargüen B, Zaragoza K, de la Peña L, Llombart-Cussac A, Oliveira M. Neoadjuvant non-pegylated liposomal doxorubicin plus paclitaxel, trastuzumab and pertuzumab in patients with HER2+ breast cancer – Final results of the SOLTI OPTI-HER HEART study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-05.

Abstract P2-08-08: Circulating tumor cells count-based nomograms to predict survival of metastatic breast cancer patients: Results from the European pooled analysis

Background: The European Pooled Analysis of CTC (EPAC) in metastatic breast cancer, based on 1,944 individual data from patients with various tumor types and clinical settings (Bidard et al, Lancet Oncol 2014), has established CTC count (CellSearch) at baseline and during therapy as a level of evidence 1 independent prognostic biomarker and demonstrated its superiority over serum blood markers. As part of the study pre-planned objectives, we sought to establish nomograms allowing accurate individual survival predictions.

Methods: Using individual data from 17 centers, we built simplified multivariate prognostic models taking into account the independent prognostic clinico-pathological (CP) characteristics including CTC count, dichotomized using the 5CTC/7.5ml threshold, at baseline and at 3-5 weeks after the start of a new treatment regimen, and derived nomograms for progression-free survival (PFS) and overall survival (OS) prediction at baseline and after 3-5 weeks of treatment. We report here the internal validation of these nomograms. Discrimination of the models was assessed using the c-index estimated by a jackknife procedure and the calibration was visually assessed through 10-fold crossvalidated calibration plots at 1,2,3 years for OS and 1,2 years for PFS.

Results: Multivariate models at baseline for PFS and OS were fitted on 1501 and 568 individual patient data with CTC count at baseline and CTC count at baseline and after 3-5 weeks, respectively. Models include tumor subtype, the number of previous chemotherapy lines (0/1/≥2), PS, age (&lt;=50/&gt;50-65/&gt;65 years), metastasis-free intervals (0/&gt;0-3/&gt;3 years), metastatic sites (liver and CNS) and CTC count at baseline and eventually at 3-5 weeks of treatment. The C-index increased from 0.722 to 0.755 (increase in C-index:0.033, 95% CI [0.019;0.045]) when adding baseline CTC to the CP only model for OS (n=1501). For those patients with CTC values at 3-5 weeks (n=568), there was an additional increase in the C-index when adding CTC at 3-5 weeks to a model with already CP and baseline CTC from 0.731 to 0.743 (increase in C-index 0.013, 95% CI [-0.004;0.025]). The model with CP and baseline CTC counts showed a good calibration for OS at 1,2,3 years and the model with CP, baseline CTC and CTC count at 3-5 weeks a moderately good calibration. Similar results were obtained for PFS.

Conclusion: From the largest database with individual CTC data, we were able to build PFS and OS survival nomograms, with satisfactory discrimination and calibration. Our planned next step is to validate the nomogram in an additional cohort.

Citation Format: Bidard F-C, Peeters D, Fehm T, Nole F, Gisbert-Criado R, Mavroudis D, Grisanti S, Generali D, Garcia-Saenz JA, Stebbing J, Caldas C, Gazzaniga P, Manso L, Zamarchi R, Fernandez de Lascoiti A, de Mattos-Arruda L, Ignatiadis M, van Laere SJ, Meier-Stiegen F, Sandri M-T, Vidal-Martinez J, Politaki E, Consoli F, Bottini A, Diaz-Rubio E, Krell J, Dawson S-J, Raimondi C, Rutten A, Janni W, Munzone E, Carañana V, Agelaki S, Almici C, Dirix L, Solomayer E, Zorzino L, Reis-Filho JS, Squifflet P, Pantel K, Beije N, Sleijfers S, Pierga J-Y, Michiels S. Circulating tumor cells count-based nomograms to predict survival of metastatic breast cancer patients: Results from the European pooled analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-08.

SEOM clinical guidelines in early-stage breast cancer 2015

Breast cancer is a major public health problem. Despite remarkable advances in early diagnosis and treatment, one in three women may have metastases since diagnosis. Better understanding of prognostic and predictive factors allows us to select the most appropriate adjuvant therapy in each patient. In these guidelines, we summarize current evidence for the medical management of early-stage breast cancer.

Abstract PD6-5: Pooled analysis of circulating tumor cells in metastatic breast cancer: Findings from 1944 individual patients data

Background: Clinical validity of CTCs (CellSearch®) in metastatic breast cancer (MBC) patients has previously been assessed in studies with limited statistical power. We aimed to pool all European studies to obtain high-level evidence on the prognostic value of CTCs, to investigate their effects across different clinico-pathological characteristics and therapies and to further validate the MD Anderson/Institut Curie/Fox Chase CTC-based prognostic nomogram established in first-line treated MBC patients (Giordano et al, Clin Cancer Res 2013).

Material and methods: Methods were predefined in a written protocol. In December 2012, we searched for eligible studies that accrued patients in 2003-2012. We contacted all European laboratories using CellSearch®. We used likelihood ratio tests (LR) in Cox regression models stratified by study to assess the independent prognostic value of CTC when added to a clinicopathological (CP) model for progression-free (PFS) and overall survival (OS). Landmark analyses were used to assess the prognostic effect of early changes in CTC. The CTC-based nomogram (http://cancernomograms.com/CTCOnline.html) score was retrieved for every patient; we calculated C-indices, drew calibration plots and Kaplan-Meier curves according to quintiles of the nomogram score.

Results: We collected individual data of 1944 MBC patients, from 20 different studies (some unpublished), from 17 centers in 7 European countries. We observed 1507 PFS events and 929 deaths. Baseline CTC count was significantly associated with several patient characteristics, such as performance status (PS, p&lt;10-4), synchronous metastasis (p&lt;10- 2) tumor subtype (p&lt;10-4), liver & bone metastases (p&lt;10-4), CEA & CA15-3 levels (p&lt;10-4). The CP model for OS included PS, MBC subtypes, number of previous lines of treatment, patient's age, metastasis-free interval, metastatic sites (p&lt;0.01 for all). In a multivariate analysis containing the CP model parameters and CTC count at baseline, elevated CTC count (≥5) was a significant independent predictor of OS (n = 1444, HR = 2.7, 95%CI [2.2-3.2], LR p&lt;10-4). Baseline serum markers added either no or marginal effect to the CP plus baseline CTC model for OS. In contrast, early changes in CTC status at week 3-5 significantly added prognostic information for OS to the model with CP factors and baseline CTC+ (n = 569, HR = 1.8 [2.2-3.2], LR p&lt;0.001). In the population of interest (MBC treated by first line chemotherapy, n = 402 patients, 176 deaths), the CTC-based nomogram exhibited a good C-index for OS (0.69), was well calibrated and showed clear separation of the survival curves. Additional results, including subgroup analyses by tumor subtype and treatments will be presented at the meeting.

Conclusions: This pooled analysis is the largest study ever reported on CTC in MBC, with a previously unreached statistical power. It provides a clear level-of-evidence 1 on the independent prognostic value of CTCs before and during treatment in MBC. Also, the CTC-based prognostic nomogram is independently validated.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD6-5.

P5-11-05: Measurement of Neoadjuvant Chemotherapy Tumor Response in Locally Advanced Breast Cancer by Three Methodologies. Correlation with Overall Survival

Background

Measurement of residual disease following neoadjuvant chemotherapy that accurate predicts long-term survival in locally advanced breast cancer (LABC) is an essential requirement for new drugs efficacy evaluation. Several methods to assess neoadjuvant chemotherapy tumor response have been described. However, to our knowledge, agreement between methods and correlation with survival in independent prospective cohorts has not been reported.

Patients & Methods: In this study we report neoadjuvant chemotherapy tumor response and survival in 151 consecutive LABC patients, included in a neoadjuvant clinical trial (http://www.clinicaltrials.gov; NCT00123929). Patients were randomized to either neoadjuvant docetaxel 100 mg/m2 every 21 days or neoadjuvant doxorubicin 75mg/m2, every 21 days, for 4 cycles. Following surgery, response was established according to three methodologies: the measurement of residual breast cancer burden (RBC) as described by Symman's (Symmans WF et al. J Clin Oncol. 2007;25:4414–22), Miller and Payne classification (Ogston KN et al. Breast. 2003;12:320–7) and RECIST criteria. Regarding to Symmans classification we have evaluate both RBC index, as a continuous variable, and RBC classes as a categorical variable (RBC-0,I,II,III). Kappa Cohen's coefficient (K) was used to test agreement between methods. We assessed the correlation between treatment outcome and overall survival (OS) by calculating the Harrell's C- statistic.

Results: Median of follow up was 51.9 months. All three methods showed a moderate capacity to classify patients according to OS. The C-statistic to predict OS was 0.76 (IC: 0.67- 0.84) for RBC index and 0.71 (IC: 0.64−0.78) for RBC classes, 0.68 (IC: 0.58−0.78) for RECIST criteria and 0.69 (0.60−0.78) for Miller and Payne classification. Interesting, we did not encountered any death events within RCB-0 class. No significant differences were found between C-statistic when patients were stratified according to therapy. In order to assess the agreement between techniques, we grouped categories 1 and 2 of Miller and Payne classification in 1 category. The agreement between Miller and Payne classification and Symmans method was very high (K=0.87). In contrast, we found a moderate-fair agreement between Miller and Payne classification and RECIST criteria (K=0.46) and Symmans method and RECIST criteria (K=0.27).

Conclusion: All three methods predicted fairly well OS. RCB-0 identified the best outcome group. The agreement between methodologies based in pathology analyses was very high. However, the agreement falls off when these methodologies were compared with RECIST criteria.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-11-05.

P1-12-09: Safety and Efficacy of Neratinib in Combination with Capecitabine in Patients with ErbB2-Positive Breast Cancer

Background: Neratinib (HKI-272) is an irreversible pan-ErbB receptor tyrosine kinase inhibitor that has shown antitumor activity in patients with ErbB2+ breast cancer. Capecitabine has demonstrated efficacy and tolerability in combination with lapatinib, a reversible dual ErbB1/ErbB2 kinase inhibitor, in patients with ErbB2+ advanced breast cancer. The current study evaluated the safety and clinical activity of neratinib in combination with capecitabine.

Methods: In part 1 of this open-label, phase 1/2 study, the maximum tolerated dose (MTD) of neratinib in combination with capecitabine was determined in adults with advanced solid tumors. Part 2 of the study further evaluated the safety and clinical activity of neratinib plus capecitabine at the MTD in adults with confirmed ErbB2+ metastatic or locally advanced breast cancer (ECOG Performance Status of 0–2). Eligible patients had received prior taxane treatment and ≥1 prior trastuzumab-containing regimen for ≥6 weeks for metastatic or locally advanced disease. The primary endpoint of part 2 was objective response rate (ORR); tumor responses were assessed by investigators using modified RECIST version 1.0 guidelines every 6 weeks.

Results: In part 1 (n = 33), the MTD was determined to be neratinib 240 mg/day plus capecitabine 750 mg/m2 twice daily on Days 1 to 14 of each 21-day cycle. In part 2, as of April 2011, 72 female patients (median age of 52 years [range, 33–79 years]) with ErbB2+ breast cancer were enrolled and treated at the MTD; 7 patients had prior lapatinib exposure and all had prior trastuzumab and taxane exposure. As of the snapshot date, 56% of patients at the MTD were still participating in the study. The most common drug-related adverse events (AEs) in part 2 were diarrhea (89%), palmar-plantar erythrodysesthesia (57%), nausea (33%), vomiting (26%), and decreased appetite (22%). Grade 3/4 drug-related AEs in ≥5% of patients were diarrhea (25%) and palmar-plantar erythrodysesthesia (13%). Eight patients withdrew from part 2 due to AEs, including 4 who withdrew due to diarrhea. Dose interruptions of neratinib and capecitabine, respectively, due to AEs were required by 19 and 29 patients; dose reductions due to AEs were required by 8 and 22 patients. As of June 2010 (interim analysis), 22 patients were evaluable for efficacy in part 2 of the study. Of these 22 patients, 11 achieved a partial response for an ORR of 50%. An additional 2 patients maintained stable disease for ≥24 weeks, resulting in a clinical benefit rate of 59%, and 8 patients had stable disease for &lt;24 weeks. One patient had progressive disease without achieving a response or stable disease. Updated efficacy data will be presented.

Conclusions: The results of this study indicate that neratinib combined with capecitabine is tolerable and has promising antitumor activity in patients with ErbB2+ metastatic or locally advanced breast cancer pretreated with trastuzumab. This study supports further evaluation of this combination in ErbB2+ breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-09.

Trastuzumab associated with successive cytotoxic therapies beyond disease progression in metastatic breast cancer

10617

Background: Whether trastuzumab should be continued after tumor progression remains unknown.We describe the activity of successive trastuzumab-containing regimens in patients with HER2-overexpressing metastatic breast cancer, as well as the response rate, time to progression and predictive factors for response. Methods: Descriptive retrospective study of trastuzumab activity in patients with HER2-overexpressing metastatic breast cancer treated at our hospital from 10/1999 to 07/2005. Results: 93 consecutive patients were evaluated obtaining an objective response rate (OR) for first-time administration of trastuzumab of 46.2%; stable disease (SD) 24.7%; clinical benefit (CB) 71%. Median time-to-progression (TTP) was 5 months (range: 1–39+). A total of 47 pts (50.5%) received a second trastuzumab-containing regimen with an OR of 29.8%; SD 21.3%; CB 51.1%; TTP 4 months (range: 1–31). A total of 21 pts (22.6%) received a third trastuzumab-containing regimen; OR 38.1%; SD 23.8%; CB 61.9%; TTP 4 months (range: 1–30+). A total of 10 pts (10.8%) received a fourth trastuzumab-containing regimen; OR 20%; SD 20%; CB 40%; TTP 4 months (range: 1–37). 5 pts (5.4%) received a fifth trastuzumab-containing regimen; OR 0%; SD 60%. Age < 45 years is a significant prognostic factor (p: 0.005, 95% CI, OR 5.6 (1.5–20.6)). A better response rate in the successive trastuzumab-containing regimens was observed, when there was a response in the first regimen: p = 0.04; 95% CI; OR 3.84 (1.07–14.65). With a follow-up of 16,5 months 45 pts (48,4%) are alive. Conclusions: Trastuzumab-containing therapies beyond disease progression in metastatic breast cancer show activity. There were more responses in younger pts. Those pts who had a previous response to trastuzumab therapy were more likely to respond to successive trastuzumab-containing regimens. Additional controlled studies are needed to test this approach.

No significant financial relationships to disclose.

Methotrexate, uracil and tegafur, and leucovorin chemotherapy for patients with breast cancer in progression after high-dose chemotherapy with peripheral blood progenitor cell transplant: a phase II study

Thirty-four patients with metastatic breast cancer (MBC) who had progression of disease after high-dose chemotherapy (HDCT) with peripheral blood progenitor cell support (PBPC) had methotrexate, uracil and tegafur (UFT), and leucovorin (MUL) therapy administered: methotrexate administered intramuscularly in combination with UFT given orally and leucovorin given orally. All patients had received extensive prior chemotherapy including a high-dose regimen with PBPC support. Two complete responses (CR) and 11 partial responses (PR) were observed (objective response rate: 13/34 or 38%, 95% confidence interval 22-56%). Seven additional patients had stable disease (SD), 4 of whom (12% of the total population) of 6 months or longer duration, with the clinical benefit rate (CR + PR + SD of at least 6-month duration) reaching 50%. Median follow-up was 38 months, and the median time to progression and the median overall survival time from the start of MUL were 5.5 and 11 months, respectively. Toxicity was mainly gastrointestinal. Eight patients (24%) had World Health Organization grade II or greater diarrhea and/or enteritis and, consequently, the UFT dose was reduced. Emesis was mild and easily manageable with thiethylperazine given orally. The regimen did not produce significant myelosuppression or alopecia. In conclusion, patients with MBC retain chemosensitivity even when they progress after HDCT/PBPC and can be treated again with chemotherapy. MUL is active and well tolerated in patients with MBC progressing after HDCT. Further studies with this regimen, as salvage chemotherapy or as maintenance chemotherapy after HDCT/PBPC, would appear to be warranted.