Unleashing NK- and CD8 T cells by combining monalizumab and trastuzumab for metastatic HER2-positive breast cancer: Results of the MIMOSA trial

The large majority of patients with HER2-positive metastatic breast cancer (MBC) will eventually develop resistance to anti-HER2 therapy and die of this disease. Despite, relatively high levels of stromal tumor infiltrating lymphocytes (sTILs), PD1-blockade has only shown modest responses. Monalizumab targets the inhibitory immune checkpoint NKG2A, thereby unleashing NK- and CD8 T cells. We hypothesized that monalizumab synergizes with trastuzumab by promoting antibody-dependent cell-mediated cytotoxicity. In the phase II MIMOSA-trial, HER2-positive MBC patients were treated with trastuzumab and 750 mg monalizumab every two weeks. Following a Simon's two-stage design, 11 patients were included in stage I of the trial. Treatment was well tolerated with no dose-limiting toxicities. No objective responses were observed. Therefore, the MIMOSA-trial did not meet its primary endpoint. In summary, despite the strong preclinical rationale, the novel combination of monalizumab and trastuzumab does not induce objective responses in heavily pre-treated HER2-positive MBC patients.

PD-L1 blockade in combination with carboplatin as immune induction in metastatic lobular breast cancer: the GELATO trial

Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, but ILC-specific trials are lacking. Translational research revealed an immune-related ILC subset, and in mouse ILC models, synergy between immune checkpoint blockade and platinum was observed. In the phase II GELATO trial ( NCT03147040 ), patients with metastatic ILC were treated with weekly carboplatin (area under the curve 1.5 mg ml-1 min-1) as immune induction for 12 weeks and atezolizumab (PD-L1 blockade; triweekly) from the third week until progression. Four of 23 evaluable patients had a partial response (17%), and 2 had stable disease, resulting in a clinical benefit rate of 26%. From these six patients, four had triple-negative ILC (TN-ILC). We observed higher CD8+ T cell infiltration, immune checkpoint expression and exhausted T cells after treatment. With this GELATO trial, we show that ILC-specific clinical trials are feasible and demonstrate promising antitumor activity of atezolizumab with carboplatin, particularly for TN-ILC, and provide insights for the design of highly needed ILC-specific trials.

Carboplatin-Cyclophosphamide or Paclitaxel without or with Bevacizumab as First-Line Treatment for Metastatic Triple-Negative Breast Cancer (BOOG 2013-01)

Background

The addition of bevacizumab to chemotherapy conferred a modest progression-free survival (PFS) benefit in metastatic triple-negative breast cancer (mTNBC). However, no overall survival (OS) benefit has been reported. Also, its combination with carboplatin-cyclophosphamide (CC) has never been investigated.

Methods

The Triple-B study is a multicenter, randomized phase IIb trial that aims to prospectively validate predictive biomarkers, including baseline plasma vascular endothelial growth factor receptor-2 (pVEGFR-2), for bevacizumab benefit. mTNBC patients were randomized between CC and paclitaxel (P) without or with bevacizumab (CC ± B or P ± B). Here we report on a preplanned safety and preliminary efficacy analysis after the first 12 patients had been treated with CC+B and on the predictive value of pVEGFR-2.

Results

In 58 patients, the median follow-up was 22.1 months. Toxicity was manageable and consistent with what was known for each agent separately. There was a trend toward a prolonged PFS with bevacizumab compared to chemotherapy only (7.0 vs. 5.2 months; adjusted HR = 0.60; 95% CI 0.33-1.08; p = 0.09), but there was no effect on OS. In this small study, pVEGFR-2 concentration did not predict a bevacizumab PFS benefit. Both the intention-to-treat analysis and the per-protocol analysis did not yield a significant treatment-by-biomarker test for interaction (p_interaction = 0.69).

Conclusions

CC and CC+B are safe first-line regimens for mTNBC and the side effects are consistent with those known for each individual agent. pVEGFR-2 concentration did not predict a bevacizumab PFS benefit.

IHC-based Ki67 as response biomarker to tamoxifen in breast cancer window trials enrolling premenopausal women

Window studies are gaining traction to assess (molecular) changes in short timeframes. Decreased tumor cell positivity for the proliferation marker Ki67 is often used as a proxy for treatment response. Immunohistochemistry (IHC)-based Ki67 on tissue from neo-adjuvant trials was previously reported to be predictive for long-term response to endocrine therapy for breast cancer in postmenopausal women, but none of these trials enrolled premenopausal women. Nonetheless, the marker is being used on this subpopulation. We compared pathologist assessed IHC-based Ki67 in samples from pre- and postmenopausal women in a neo-adjuvant, endocrine therapy focused trial (NCT00738777), randomized between tamoxifen, anastrozole, or fulvestrant. These results were compared with (1) IHC-based Ki67 scoring by AI, (2) mitotic figures, (3) mRNA-based Ki67, (4) five independent gene expression signatures capturing proliferation, and (5) blood levels for tamoxifen and its metabolites as well as estradiol. Upon tamoxifen, IHC-based Ki67 levels were decreased in both pre- and postmenopausal breast cancer patients, which was confirmed using mRNA-based cell proliferation markers. The magnitude of decrease of Ki67 IHC was smaller in pre- versus postmenopausal women. We found a direct relationship between post-treatment estradiol levels and the magnitude of the Ki67 decrease in tumors. These data suggest IHC-based Ki67 may be an appropriate biomarker for tamoxifen response in premenopausal breast cancer patients, but anti-proliferative effect size depends on estradiol levels.

POSEIDON Trial Phase 1b Results: Safety, Efficacy and Circulating Tumor DNA Response of the Beta Isoform-Sparing PI3K Inhibitor Taselisib (GDC-0032) Combined with Tamoxifen in Hormone Receptor Positive Metastatic Breast Cancer Patients

PURPOSE

The strategy of combining endocrine therapy with PI3K-mTOR inhibition has shown promise in estrogen receptor (ER)-positive breast cancer, but new agents and combinations with a better therapeutic index are urgently needed. Taselisib is a potent, selective, beta-isoform-sparing PI3 kinase inhibitor.

PATIENTS AND METHODS

30 patients with ER-positive, metastatic breast cancer who had failed prior endocrine therapy were treated with escalating doses of taselisib (2 or 4 mg in an intermittent or continuous schedule) combined with tamoxifen 20 mg once daily in this phase 1b study using a "rolling six" design.

RESULTS

Taselisib combined with tamoxifen was generally well tolerated, with treatment-emergent adverse events as expected for this class of drugs, including diarrhea (13 patients, 43%), mucositis (10 patients, 33%), and hyperglycemia (8 patients, 27%). No dose-limiting toxicities were observed. Objective responses were seen in 6 of 25 patients with RECIST-measurable disease (ORR 24%). Median time to disease progression was 3.7 months. Twelve of 30 patients (40%) had disease control for 6 months or more. Circulating tumor (ct)DNA studies using next-generation tagged amplicon sequencing identified early indications of treatment response and mechanistically relevant correlates of clinical drug resistance (e.g., mutations in KRAS, ERBB2) in some patients.

CONCLUSIONS

Taselisib can be safely combined with tamoxifen at the recommended phase 2 dose of 4 mg given once daily on a continuous schedule. Preliminary evidence of antitumor activity was seen in both PIK3CA mutant and wild-type cancers. The randomized phase 2 part of POSEIDON (testing tamoxifen plus taselisib or placebo) is currently recruiting.

Adjuvant dose-dense doxorubicin-cyclophosphamide versus docetaxel-doxorubicin-cyclophosphamide for high-risk breast cancer: First results of the randomised MATADOR trial (BOOG 2004-04)

BACKGROUND

Dose-dense administration of chemotherapy and the addition of taxanes to anthracycline-based adjuvant chemotherapy have improved breast cancer survival substantially. However, clinical trials directly comparing the additive value of taxanes with dose-dense anthracycline-based chemotherapy are lacking.

PATIENTS AND METHODS

In the multicentre, randomised, biomarker discovery Microarray Analysis in breast cancer to Tailor Adjuvant Drugs Or Regimens (MATADOR) trial, patients with pT1-3, pN0-3 breast cancer were randomised (1:1) between six adjuvant cycles of doxorubicin 60 mg/m² and cyclophosphamide 600 mg/m² every 2 weeks (ddAC) and six cycles of docetaxel 75 mg/m², doxorubicin 50 mg/m² and cyclophosphamide 500 mg/m² every 3 weeks (TAC). The primary objective was to discover a predictive gene expression profile for ddAC and TAC benefit. Here we report the preplanned secondary end-point recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Between 2004 and 2012, 664 patients were randomised. At 5 years, RFS was 87% (95% confidence interval [CI] 83%-91%) in the ddAC-treated patients and 88% (84-92%) in the TAC-treated subgroup (hazard ratio [HR] 0.89, 95% CI 0.62-1.28, P = 0.53). OS at 5 years was 93% (90%-96%) in the ddAC-treated and 94% (91%-97%) in the TAC-treated patients (HR 0.89, 95% CI 0.57-1.39, P = 0.61). Anaemia was more frequent in ddAC-treated patients (62/327 patients [18.9%] versus 15/319 patients [4.7%], P < 0.001) and diarrhoea (21 [6.4%] versus 53 [16.6%], P<0.001) and peripheral neuropathy (15 [4.6%] versus 46 [14.4%], P < 0.001) were observed more often in TAC-treated patients.

CONCLUSIONS

With a median follow-up of 7 years, no significant differences in RFS and OS were observed between six adjuvant cycles of ddAC and TAC in high-risk breast cancer patients.

TRIAL REGISTRATION NUMBERS

ISRCTN61893718 and BOOG 2004-04.

Independent replication of polymorphisms predicting toxicity in breast cancer patients randomized between dose-dense and docetaxel-containing adjuvant chemotherapy

Introduction

Although pharmacogenomics has evolved substantially, a predictive test for chemotherapy toxicity is still lacking. We compared the toxicity of adjuvant dose-dense doxorubicin-cyclophosphamide (ddAC) and docetaxel-doxorubicin-cyclophosphamide (TAC) in a randomized multicenter phase III trial and replicated previously reported associations between genotypes and toxicity.

Results

646 patients (97%) were evaluable for toxicity (grade 2 and higher). Whereas AN was more frequent after ddAC (P < 0.001), TAC treated patients more often had PNP (P < 0.001). We could replicate 2 previously reported associations: TECTA (rs1829; OR 4.18, 95% CI 1.84-9.51, P = 0.001) with PNP, and GSTP1 (rs1138272; OR 2.04, 95% CI 1.13-3.68, P = 0.018) with PNP.

Materials and methods

Patients with pT1-3, pN0-3 breast cancer were randomized between six cycles A60C600 every 2 weeks or T75A50C500 every 3 weeks. Associations of 13 previously reported single nucleotide polymorphisms (SNPs) with the most frequent toxicities: anemia (AN), febrile neutropenia (FN) and peripheral neuropathy (PNP) were analyzed using logistic regression models.

Conclusions

In this independent replication, we could replicate an association between 2 out of 13 SNPs and chemotherapy toxicities. These results warrant further validation in order to enable tailored treatment for breast cancer patients.

Abstract P5-14-03: Adjuvant dose dense doxorubicin-cyclophosphamide (ddAC) or docetaxel-AC (TAC) for high-risk breast cancer: First results of the randomized MATADOR trial (BOOG-2004-04)

Background: Anthracycline-based adjuvant chemotherapy has substantially improved breast cancer survival. Both the addition of taxanes as well as using a dose dense treatment schedule can further ameliorate outcome, but inter-individual differences exist. Here we present the efficacy and toxicity of dose dense scheduled doxorubicin/cyclophosphamide (ddAC) versus docetaxel/doxorubicin/cyclophosphamide (TAC), which is, to our knowledge, the first direct comparison of these treatment regimens.

Methods: In this Dutch, multicenter phase III trial (ISRCTN61893718), patients with pT1-3, pN0-3, M0 breast cancer were randomized between six cycles of either A60C600 every 2 weeks or T75A50C500 every 3 weeks. All patients received pegfilgrastim. Patients were evaluated for recurrence-free survival (RFS) and overall survival (OS). Survival was compared in a Cox regression analysis and adjusted for known prognostic factors. These factors include age, type of surgery, tumor size, histological grade, ER/PR status, HER2 status, and lymph node status. Adverse events were reported according to the common toxicity criteria (CTCAE version 3.0).

Results: Between 2004 and 2012, 664 patients were enrolled of whom 531 (80%) had node positive disease. At a median follow up of 5 years, OS was 92% in the ddAC treated subgroup and 93% in the TAC treated subgroup (adjusted hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.42-1.34, intention to treat population). Forty-two breast-cancer specific deaths were equally divided over both treatment arms. Similarly, no significant difference in RFS was observed between both treatment groups (adjusted HR 0.85, 95% CI 0.55-1.32). Molecular subtypes were defined by St. Gallen criteria: 548 patients (83%) had estrogen receptor positive disease and 102 patients (15%) triple negative disease. No heterogeneity regarding treatment efficacy was observed in these subtypes. In particular, there was no survival benefit for ddAC or TAC in the triple negative subtype. Both treatment regimens were well tolerated. Whereas anemia was more frequent in ddAC treated patients (19% vs 4.7%; p&lt;0.001), peripheral neuropathy occurred more frequently in TAC treated patients (4.6% vs 14.4%; p&lt;0.001). The frequency of febrile neutropenia was not significantly different between the treatment arms (11% vs 12.5%; n.s.). Six patients developed congestive heart failure: 2 ddAC treated patients, 4 TAC treated patients. One ddAC treated patient and one TAC treated patient were diagnosed with acute myeloid leukemia after study treatment; another patient in the ddAC treatment group developed myelodysplastic syndrome.

Conclusions: At a median follow up of 5 years no significant survival differences were observed between adjuvant ddAC and TAC, in all patients and in molecular subgroups, including triple negative. Our findings are in line with the Oxford overview, which reported no significant differences between taxane-based chemotherapy and more, non-taxane based chemotherapy given in a dose dense schedule. ddAC could be a reasonable alternative for patients with a contra-indication for TAC.

Citation Format: van Rossum AGH, Oosterkamp HM, van Werkhoven E, Opdam M, Mandjes IAM, van Leeuwen-Stok E, van Tinteren H, Kok M, Imholz ALT, Portielje JEA, Bos MMEM, van Bochove A, Wesseling J, Rutgers EJ, Rodenhuis S, Linn SC. Adjuvant dose dense doxorubicin-cyclophosphamide (ddAC) or docetaxel-AC (TAC) for high-risk breast cancer: First results of the randomized MATADOR trial (BOOG-2004-04) [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 P5-14-03.

Abstract OT2-01-11: Phase II of POSEIDON: A phase Ib / randomized phase II trial of tamoxifen plus taselisib or placebo in hormone receptor positive, HER2 negative, metastatic breast cancer patients with prior exposure to endocrine treatment

Background: The combination of PI3K-AKT-mTOR pathway inhibitors with endocrine therapy can improve clinical outcomes of hormone receptor positive (HR+) metastatic breast cancer (MBC) patients. Taselisib is a potent and selective PI3K inhibitor, with greater selectivity against mutant (MUT) PI3Kα isoforms than wild-type (WT) via a unique mechanism. Phase Ib data of POSEIDON with Taselisib + tamoxifen (TAM) demonstrated encouraging activity in patients with heavily pre-treated MBC, with an acceptable toxicity profile (Baird et al, ASCO 2016). The recommended phase II dose (RP2D) was Taselisib 4mg plus TAM 20mg, both administered on a daily continuous schedule. ctDNA monitoring may have value in drug development by (1) assessing predictive biomarkers to therapy, (2) providing an early indication of treatment response, and (3) shedding light on potential mechanisms of acquired drug resistance. In some patients included in phase Ib of POSEIDON, tumor response was preceded by a corresponding early change in plasma PIK3CA ctDNA levels. Methods: The phase II portion of the POSEIDON trial is a two-arm, randomized, double blind study of Taselisib plus TAM versus placebo (PLA) plus TAM in pre- and postmenopausal women with HR+/HER2- MBC. In the first part of the Phase II, 180 patients will be randomized (1:1) to receive continuous TAM with either Taselisib at the RP2D or PLA until disease progression, unacceptable toxicity or patient / physician decision. Crossover is allowed upon progressive disease in those patients receiving PLA plus TAM, after collection of tumor and blood samples for exploratory biomarker analysis. Stratification is based on menopausal status, histology [lobular breast cancer (LBC) vs. ductal/others], PIK3CA mutation (WT vs. exon 9 vs. exon 20), prior everolimus, timing of recurrence/progression after prior endocrine therapy, number of prior chemotherapy (CT) lines, and treatment center. After recruiting the initial 180 patients, trial will focus in LBC, until a total number of 110 patients with LBC are enrolled. Other key eligibility criteria include presence of measurable or evaluable disease (RECIST 1.1), prior progression to endocrine treatment, maximum of 5 prior CT lines in the metastatic setting, absence of diabetes under medical treatment, and absence of chronic inflammatory bowel disease. Primary endpoint is investigator-assessed PFS. Key secondary endpoints are PFS in LBC, objective response rate, clinical benefit rate, safety, and exploratory biomarker analysis (including ctDNA). The study has a 90% power at a two-sided log-rank test significance level of 0.2 to detect an HR of 0.64, which corresponds to an increase in median PFS from 4.5 months in the PLA plus TAM arm to 7 months in the Taselisib plus TAM arm. Enrollment to POSEIDON Phase II started in June 2016 (Clinicaltrials.gov NCT02285179).

Citation Format: Oliveira M, Baird RD, van Rossum AGJ, Beelen K, Garcia-Corbacho J, Mandjes IAM, Vallier AL, van Werkhoven E, Garrigós L, Kumar S, van Tinteren H, Muñoz S, Linossi C, Rosing H, Miquel JM, Schrier M, de Vries Schultink A, Saura C, Gallagher WM, Bernards R, Tabernero J, Cortés J, Caldas C, Linn SC. Phase II of POSEIDON: A phase Ib / randomized phase II trial of tamoxifen plus taselisib or placebo in hormone receptor positive, HER2 negative, metastatic breast cancer patients with prior exposure to endocrine treatment [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 OT2-01-11.

Trastuzumab in combination with weekly paclitaxel and carboplatin as neo-adjuvant treatment for HER2-positive breast cancer: The TRAIN-study

AIM

To determine the efficacy and safety of an anthracycline-free neo-adjuvant regimen consisting of weekly paclitaxel, carboplatin and trastuzumab in HER2-positive breast cancer.

PATIENTS AND METHODS

Patients with stage II or III HER2-positive breast cancer received weekly paclitaxel ([P], 70 mg/m²), trastuzumab ([T], 2 mg/kg, loading dose 4 mg/kg) and carboplatin ([C], AUC = 3 mg ml^-1 min) for 24 weeks. In weeks 7, 8, 15, 16, 23 and 24, trastuzumab was administered without chemotherapy. The primary end-point was pathologic complete response in the surgical resection specimen, defined as the absence of invasive tumour cells in breast and axilla.

RESULTS

One hundred and eleven patients were included in the study, and 108 were evaluable for the primary end-point. The pathologic complete response rate was 43% (95% confidence interval [CI]: 33-52). Median follow-up was 52 months, and the 3-year event-free survival was 88% (95% CI: 82-94), and the 3-year overall survival was 92% (95% CI: 88-98). The most common grade 3-4 adverse events were neutropenia (67%) and thrombocytopenia (43%). Less than five percent of patients experienced febrile neutropenia. No symptomatic left ventricular systolic dysfunction was observed during neo-adjuvant treatment.

CONCLUSION

An anthracycline-free neo-adjuvant regimen of weekly paclitaxel, trastuzumab and carboplatin is highly effective in HER2-positive breast cancer with manageable toxicity.

The prognostic value of the neoadjuvant response index in triple-negative breast cancer: validation and comparison with pathological complete response as outcome measure

The Neoadjuvant response index (NRI) has been proposed as a simple measure of downstaging by neoadjuvant treatment in breast cancer. It was previously found to predict recurrence-free survival (RFS) in triple-negative (TN) breast cancer. It was at least as accurate as the standard binary system, the absence or presence of a pathological complete remission (pCR), which is the commonly employed outcome measure. The NRI was evaluated in an independent consecutive series of patients to validate the previous findings. Univariable and multivariable analyses were done to assess the predictive value of clinical parameters and of the NRI for RFS. We combined the original and validation series of patients to build a multivariable predictive model for RFS after neoadjuvant chemotherapy in TN breast cancer. The validation set (N = 108) confirmed that patients with a higher-than-median NRI (>0.7) had excellent RFS (P = 0.002), similar to that of patients who had achieved a pCR. Multivariable analysis in 191 patients showed that the NRI was a strong independent predictor of RFS (P = 0.0002), with N-stage (P = 0.001) and T-stage (P = 0.014) ranking second and third, respectively. Importantly, among patients who did not achieve a pCR (NRI values below 1), higher NRI values were still associated with better RFS. The NRI is a simple method and a practical tool to predict RFS in TN breast cancer patients treated with neoadjuvant chemotherapy. It adds prognostic information to the presence or absence of pCR and could be useful to compare the efficacies of different chemotherapy regimens.

Neoadjuvant chemotherapy in ER+ HER2- breast cancer: response prediction based on immunohistochemical and molecular characteristics

A pathological complete remission (pCR) is rarely achieved by neoadjuvant chemotherapy in estrogen receptor-positive (ER+) HER2-negative (HER2-) tumors. Therefore, its use might be questionable in specific groups of this tumor type. To select which patients benefit and which could be spared neoadjuvant chemotherapy, we tested standard pathology and molecular markers in ER+ HER2- breast tumors. Pretreatment biopsies were available from 211 ER+ HER2- tumors, who had been treated with neoadjuvant chemotherapy (adriamycin/cyclophosphamide). mRNA expression data were available for 132 tumors. We determined progesterone receptor expression (PR), endocrine sensitivity, HER2 expression, histology, proliferation, and molecular subtypes. We correlated these data to chemotherapy response using pCR rates and the previously published neoadjuvant response index (NRI). PR-negative tumors (n = 65, 30.8%) and luminal B type tumors (n = 43, 20.4%) responded significantly better to chemotherapy than other tumors. These associations remained significant in multivariate analysis. However, even in the subgroup of patients with the lowest response rate, comprising tumors that had both a positive-PR expression and the luminal A subtype (n = 58, 44%), the majority of the patients had downstaging because of chemotherapy. For histology (lobular vs. ductal), endocrine sensitivity, and proliferation, no associations with chemotherapy response were observed. Gene expression array analysis resulted in 28 significant genes (FDR < 0.1). PR expression and luminal B status are associated with a better response to neoadjuvant chemotherapy. However, both markers had only weak response predictive power, and it was not possible to identify a subgroup with no or only minimal chemotherapy benefit. Therefore, the decision to refrain from neoadjuvant chemotherapy to ER+ HER2- breast tumors should not be based on predictive markers, but exclusively on estimates of prognosis.

Lapatinib: clinical benefit in patients with HER 2-positive advanced breast cancer

BACKGROUND

Lapatinib, a tyrosine kinase inhibitor of human epidermal growth factor receptor 2 (HER2), has shown activity in combination with capecitabine in patients with HER2-positive advanced breast cancer progressive on standard treatment regimens. We present results on preapproval drug access for this combination in such patients occurring in the general oncology practice in the Netherlands.

METHODS

Patients with HER2-positive advanced breast cancer progressive on schedules containing anthracyclines, taxanes, and trastuzumab were eligible. Brain metastases were allowed if stable. Lapatinib 1250 mg÷day was given continuously in combination with capecitabine 1000 mg÷m2 twice daily for two weeks in a three-week cycle. Efficacy was assessed by use of response evaluation criteria in solid tumours version 1.0. Progression-free survival (PFS) and overall survival (OS) were calculated.

RESULTS

Eighty-three patients were enrolled from January 2007 until July 2008. The combination was generally well tolerated and the most common drug-related serious adverse events were nausea and÷or vomiting (5%) and diarrhoea (2%). Seventy-eight patients were evaluable for response. Clinical benefit (response or stable disease for at least 12 weeks) was observed in 50 patients (64%) of whom 15 had a partial response and 35 stable disease. The median PFS and OS were 17 weeks (95% CI: 13 to 21) and 39 weeks (95% CI: 24 to 54), respectively. For OS, higher Eastern Cooperative Oncology Group (ECOG) status (p=0.016), brain metastases at study entry (p=0.010) and higher number of metastatic sites (p=0.012) were significantly negative predictive factors.

CONCLUSION

In a patient population with heavily pretreated HER2-positive advanced breast cancer lapatinib plus capecitabine was well tolerated and offered clinical benefit.