Dual neoadjuvant blockade plus chemotherapy versus monotherapy for the treatment of women with non-metastatic HER2-positive breast cancer: a systematic review and meta-analysis

BACKGROUND

We aimed to determine the effect of dual anti-HER2 blockade compared to monotherapy on clinically important outcomes.

METHODS

We carried out a systematic review updated until July 2022. The outcomes included pathological complete response (pCR), clinical response, event-free survival, and overall survival.

RESULTS

We identified eleven randomized clinical trials (2836 patients). When comparing paclitaxel plus dual treatment versus paclitaxel plus trastuzumab or lapatinib, dual treatment was associated with a higher probability of achieving a pathological complete response (OR 2.88, 95% CI 2.02-4.10). Addition of a taxane to an anthracycline plus cyclophosphamide and fluorouracil, plus lapatinib or trastuzumab, showed that the dual treatment was better than lapatinib alone (OR 2.47, 95% CI 1.41-4.34), or trastuzumab alone (OR 1.89, 95% CI 1.13-3.16). Dual treatment may result in an increase in survival outcomes and tumour clinical response, although such benefits are not consistent for all the combinations studied.

CONCLUSIONS

The use of dual blockade with combinations of trastuzumab and pertuzumab can be recommended for the neoadjuvant treatment of women with HER2-positive breast cancer. PROSPERO Registration number: CRD42018110273.

Trastuzumab deruxtecan versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer: updated results from DESTINY-Breast03, a randomised, open-label, phase 3 trial

BACKGROUND

An improvement in progression-free survival was shown with trastuzumab deruxtecan versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer in the progression-free survival interim analysis of the DESTINY-Breast03 trial. The aim of DESTINY-Breast03 was to compare the efficacy and safety of trastuzumab deruxtecan versus trastuzumab emtansine.

METHODS

This open-label, randomised, multicentre, phase 3 trial was done in 169 study centres in North America, Asia, Europe, Australia, and South America. Eligible patients were aged 18 or older, had HER2-positive unresectable or metastatic breast cancer previously treated with trastuzumab and a taxane, had an Eastern Cooperative Oncology Group performance status 0-1, and at least one measurable lesion per Response Evaluation Criteria in Solid Tumours version 1.1. Patients were randomly assigned (1:1) to receive trastuzumab deruxtecan 5·4 mg/kg or trastuzumab emtansine 3·6 mg/kg, both administered by intravenous infusion every 3 weeks. Randomisation was stratified by hormone receptor status, previous treatment with pertuzumab, and history of visceral disease, and was managed through an interactive web-based system. Within each stratum, balanced block randomisation was used with a block size of four. Patients and investigators were not masked to the treatment received. The primary endpoint was progression-free survival by blinded independent central review. The key secondary endpoint was overall survival and this prespecified second overall survival interim analysis reports updated overall survival, efficacy, and safety results. Efficacy analyses were performed using the full analysis set. Safety analyses included all randomly assigned patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03529110.

FINDINGS

Between July 20, 2018, and June 23, 2020, 699 patients were screened for eligibility, 524 of whom were enrolled and randomly assigned to receive trastuzumab deruxtecan (n=261) or trastuzumab emtansine (n=263). Median duration of study follow-up was 28·4 months (IQR 22·1-32·9) with trastuzumab deruxtecan and 26·5 months (14·5-31·3) with trastuzumab emtansine. Median progression-free survival by blinded independent central review was 28·8 months (95% CI 22·4-37·9) with trastuzumab deruxtecan and 6·8 months (5·6-8·2) with trastuzumab emtansine (hazard ratio [HR] 0·33 [95% CI 0·26-0·43]; nominal p<0·0001). Median overall survival was not reached (95% CI 40·5 months-not estimable), with 72 (28%) overall survival events, in the trastuzumab deruxtecan group and was not reached (34·0 months-not estimable), with 97 (37%) overall survival events, in the trastuzumab emtansine group (HR 0·64; 95% CI 0·47-0·87]; p=0·0037). The number of grade 3 or worse treatment-emergent adverse events was similar in patients who received trastuzumab deruxtecan versus trastuzumab emtansine (145 [56%] patients versus 135 [52%] patients). Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 39 (15%) patients treated with trastuzumab deruxtecan and eight (3%) patients treated with trastuzumab emtansine, with no grade 4 or 5 events in either group.

INTERPRETATION

Trastuzumab deruxtecan showed a significant improvement in overall survival versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer, as well as the longest reported median progression-free survival, reaffirming trastuzumab deruxtecan as the standard of care in the second-line setting. A manageable safety profile of trastuzumab deruxtecan was confirmed with longer treatment duration.

FUNDING

Daiichi Sankyo and AstraZeneca.

Correlation between HER2 amplification level and response to neoadjuvant treatment with trastuzumab and chemotherapy in HER2 positive breast cancer

e12641

Background: HER2 targeted therapy in combination with chemotherapy have changed the aggressive natural history of HER2-positive tumors. To select patients to be treated with this type of agents, determination of HER2 status is usually carried out by immunohistochemistry, followed by in situ hybridization in equivocal cases (2+). There are contradictory data in literature regarding correlation between level of HER2 amplification determined by FISH and early and long-term treatment benefits. Objectives: The aim of this study was to correlate quantitative results of FISH (ratio HER2/CEN17 and number of HER2 signals/nucleus) with the grade of response to neoadjuvant treatment with trastuzumab and chemotherapy. Methods: We analyzed 100 consecutive cases of stage I-III breast carcinomas treated with trastuzumab and chemotherapy in the neoadjuvant setting at A Coruña University Hospital between 2005 and 2016. At Santiago University Hospital, 4 tissue microarrays were prepared and the IQFISH (Dako-Agilent) technique was performed using pretreatment biopsies. Results: HER2 amplification was found in 92 of 100 cases studied. Pathological Complete Response (pCR) (Miller-Payne grading system) was obtained in 58% of the patients whose tumors showed amplification. No pCR was obtained in the 8 patients whose tumors were negative by FISH (not amplified). Analysis of the quantitative results demonstrated a statistical significant direct correlation between pCR and both HER2/CEN17 ratios and HER2 gene copies/nucleus (p = 0.002 and p= 0.004, respectively). We also demonstrated an association between the HER2 amplification level (both ratios and numbers of HER2 signals) and a trend toward improved disease free survival (DFS) (p = 0.451 and p= 0.619, respectively). Conclusions: HER2 amplification level determined by FISH it is a good and available predictive factor of response and must be included in pathologic reports because it can provide valuable information to oncologists on the possibilities of achieving pCR after neoadjuvant treatment in HER2-positive breast cancer. Key words: Breast cancer, FISH, HER2 amplification, trastuzumab, neoadjuvant therapy, pathological complete response.

Primary breast cancer and health related quality of life in Spanish women: The EpiGEICAM case-control study

This study evaluates the impact of breast cancer (BC) in health related quality of life (HRQL) and in psychological distress (PD) during the initial phases of the disease and looks for contributing factors. A multicentric case-control study, EpiGEICAM, was carried out. Incident BC cases and age- and residence- matched controls were included. Clinical, epidemiological, HRQL (SF-36) and PD information (GHQ-28) was collected. We used multivariable logistic regression models to estimate OR of low HRQL and of PD in cases compared to controls, and to identify factors associated with low HRQL and with PD. Among 896 BC cases and 890 control women, cases had poorer scores than both, the reference population and the control group, in all SF-36 scales. BC women with lower education, younger, active workers, never smokers, those with comorbidities, in stage IV and with surgical treatment had lower physical HRQL; factors associated with low mental HRQL were dissatisfaction with social support, being current smoker and having children. Cases had a fivefold increased odds of PD compared to controls. Managing comorbidities and trying to promote social support, especially in younger and less educated women, could improve well-being of BC patients.

Abstract P1-18-28: Myocet or carboplatin as part of chemotherapy in HER2-positive operable breast cancer treated with trastuzumab and pertuzumab in the neoadjuvant setting: Efficacy data and cardiotoxicity in 60 patients diagnosed from 2016-2019 at a single institution

Objectives: To evaluate the efficacy and cardiotoxicity profile of liposomal anthracycline or Carboplatin as part of neoadjuvant therapy added to taxanes and dual blockade in HER2-positive operable breast cancer patients.

Methods: A total of 60 patients diagnosed from August 2016 to May 2019 were included in the study. The treatment consisted of a sequential regimen of taxanes and non- pegilated liposomal anthracycline (Myocet) plus trastuzumab and pertuzumab, or taxanes in combination with carboplatin plus trastuzumab and pertuzumab. The clinical and pathologic responses were evaluated and correlated with clinical and biological factors. Pathologic complete response was defined as the total absence of invasive tumor in both breast and axillary nodes (ypT0/is ypN0).The cardiotoxicity profile was also analyzed.

Results: The median age was 52(26-77) years and 5%, 62% and 33% of patients had stage I, II and III breast cancer, respectively, while 7% had inflammatory breast cancer at diagnosis. Hormone receptor (HR) status was negative in 48%, and 65% and 50% had grade III and ki-67 value up to 35%, respectively breast cancer. 65% of patients received weekly paclitaxelx12-trastuzumab-pertuzumab followed by Myocet-cyclophosphamide with -trastuzumab x 4 cycles or this sequence but beginning with the anthracycline, 23% of patients the same regimen but with pertuzumab concurrently with all chemotherapy treatment. The remaining 12% received docetaxel-carboplatin x6 cycles plus trastuzumab and pertuzumab. All treatment was administered previous surgery.

The clinical complete response rate, was 57% and 63%, as assessed using ultrasound and MRI, respectively, and this allowed a high rate of conservative surgery (60%). The pathologic complete response (pCR) rate was 52%, and it was higher in HR-negative (61%) than in HR-positive (39%), in grade 3 (71%) than in grade 2(29%) tumors. There were not statistical significant differences in pCR between different chemotherapy treatments. Five patients showed a 10% decrease in left ventricular ejection fraction (LVEF) to below 50% at the end of neoadjuvant treatment. Asymptomatic drops in 2 patients and with heart failure symptoms in 3 of them. Myocet was part of chemotherapy in all of them. All patients recovered after discontinuation of adjuvant trastuzumab and heart medication. Two of these patients did not complete all preplanned adjuvant trastuzumab doses.

Conclusion: A sequential regimen of taxanes and non-pegilated liposomal anthracycline or carboplatin plus trastuzumab and pertuzumab was effective, with high pCR rates and a good cardiotoxicity profile.

Citation Format: Silvia Antolin, Cristina Reboredo, Rocío Lesta, Aurea Molina, Joaquin Mosquera, Patricia Cordeiro, Eva Pérez, Lourdes Calvo. Myocet or carboplatin as part of chemotherapy in HER2-positive operable breast cancer treated with trastuzumab and pertuzumab in the neoadjuvant setting: Efficacy data and cardiotoxicity in 60 patients diagnosed from 2016-2019 at a single institution [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-28.

BOMET-QoL-10 questionnaire for breast cancer patients with bone metastasis: the prospective MABOMET GEICAM study

Background

Bone metastasis (BM) is the most common site of disease in metastatic breast cancer (MBC) patients. BM impacts health-related quality of life (HRQoL). We tested prospectively the psychometric properties of the Bone Metastasis Quality of Life (BOMET-QoL-10) measure on MBC patients with BM.

Methods

Patients completed the BOMET-QoL-10 questionnaire, the Visual Analogue Scale (VAS) for pain, and a self-perceived health status item at baseline and at follow-up visits. We performed psychometric tests and calculated the effect size of specific BM treatment on patients´ HRQoL.

Results

Almost 70% of the 172 patients reported symptoms, 23.3% experienced irruptive pain, and over half were receiving chemotherapy. BOMET-QoL-10 proved to be a quick assessment tool performing well in readability and completion time (about 10 min) with 0–1.2% of missing/invalid data. Although BOMET-QoL-10 scores remained fairly stable during study visits, differences were observed for patient subgroups (e.g., with or without skeletal-related events or adverse effects). Scores were significantly correlated with physician-reported patient status, patient-reported pain, symptoms, and perceived health status. BOMET-QoL-10 scores also varied prospectively according to changes in pain intensity.

Conclusions

BOMET-QoL-10 performed well as a brief, easy-to-administer, useful, and sensitive HRQoL measure for potential use for clinical practice with MBC patients.

Trial registration

NCT03847220. Retrospectively registered on clinicaltrials.gov (February the 20th 2019).

Abstract P1-15-17: Liposomal-encapsulated doxorubicin (Myocet)as part of primary systemic therapy in HER2-positive operable breast cancer: Efficacy data, cardiotoxicity and long-term follow-up in 81 patients diagnosed from 2005-2016 at a single institution

Objectives

To evaluate the efficacy, cardiotoxicity profile and long-term benefits of liposomal doxorubicin (Myocet) as part of neoadjuvant therapy in HER2-positive operable breast cancer patients.

Methods

The treatment consisted of a sequential regimen of paclitaxel and liposomal doxorubicin (Myocet) plus trastuzumab. Clinical and pathologic response were evaluated and correlated with clinical and biological factors. Cardiotoxicity profile and long-term benefits were analyzed.

Results

Median age was 48 years and 4%, 69%, and 27% were stage I, II, and III, respectively, while 12% had inflammatory breast cancer at diagnosis. Hormone receptor (HR) status was negative in 43% and 70% were grade III.

Patients Characteristics Total number (%)Age, years Median (Range)48 (30-79)Tumor (cT)* Tx1 (1)T14 (5)T253 (66)T313 (16)T410 (12)Nodal Status N024 (30)N1-257 (70)Stage I3 (4)II56 (69)III22 (27)Hormone Receptor Status HR+35 (43)HR-46 (57)HER2 IHC 3+74 (91)IHC 2+7 (9)FISH/SISH21 (26)Grade I1(1)II22 (27)III57 (71)Unknown1 (1)Ki-67 &lt;20%6 (7)20-35%32 (40)&gt;35%43 (53)Surgical Indication at Diagnosis Mastectomy58 (72)Tumorectomy22 (27)Any surgery in breast*1 (1)* One patient had an occult carcinoma.

pCR by SubgroupsPathologic ResponsepCRNo pCR(n=81)n (%)n (%)Tumor Size (MRI)  &lt;/=5 cm26 (49)27 (51)&gt; 5 cm10 (67)5 (33)Nodes  Positive26 (46)31 (54)Negative18 (75)6 (25)Histological Subtype  Ductal43 (56)34 (44)Lobular0 (0)2 (100)Other1 (50)1 (50)Hormone Receptor  Negative23 (66)12 (34)Positive21 (46)25 (54)Ki-67  &lt;204 (67)2 (33)20-3512 (38)20 (62)&gt;3528 (65)15 (35)Grade  I0 (0)1 (100)II12 (55)10 (45)III31 (54)26 (46)

The clinical complete response rate by ultrasound and MRI were 47% and 65%, respectively, and allowed a high rate of conservative surgery (72%).

The pathologic complete response (pCR) rate in breast and axilla was 54%, higher in HR-negative (66%) than in HR-positive (46%),in ki-67&gt;35% (65%) than ki-67 between 20-35% (38%) and similar in grade III (54%) and grade II (55%).

Patients who achieved pCR had longer DFS and a trend to improve OS.

Four percent of patients showed a decrease in the left ventricular ejection fraction below 50% during treatment. All except one of them recovered after discontinuation of trastuzumab.

Conclusion: A sequential regimen of taxanes and liposomal doxorubicin (Myocet) plus trastuzumab was active with high pCR rates and long-term benefit with a very good cardiotoxicity profile.

Citation Format: Antolin S, Calvo L, Prato J, Molina A, Reboredo C, Mosquera J. Liposomal-encapsulated doxorubicin (Myocet)as part of primary systemic therapy in HER2-positive operable breast cancer: Efficacy data, cardiotoxicity and long-term follow-up in 81 patients diagnosed from 2005-2016 at a single institution [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 P1-15-17.

Multicenter Phase II Study of Lurbinectedin in BRCA-Mutated and Unselected Metastatic Advanced Breast Cancer and Biomarker Assessment Substudy

PURPOSE

This multicenter phase II trial evaluated lurbinectedin (PM01183), a selective inhibitor of active transcription of protein-coding genes, in patients with metastatic breast cancer. A unicenter translational substudy assessed potential mechanisms of lurbinectedin resistance.

PATIENTS AND METHODS

Two arms were evaluated according to germline BRCA1/2 status: BRCA1/2 mutated (arm A; n = 54) and unselected ( BRCA1/2 wild-type or unknown status; arm B; n = 35). Lurbinectedin starting dose was a 7-mg flat dose and later, 3.5 mg/m² in arm A. The primary end point was objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST). The translational substudy of resistance mechanisms included exome sequencing (n = 13) and in vivo experiments with patient-derived xenografts (n = 11) from BRCA1/2-mutated tumors.

RESULTS

ORR was 41% (95% CI, 28% to 55%) in arm A and 9% (95% CI, 2% to 24%) in arm B. In arm A, median progression-free survival was 4.6 months (95% CI, 3.0 to 6.0 months), and median overall survival was 20.0 months (95% CI, 11.8 to 26.6 months). Patients with BRCA2 mutations showed an ORR of 61%, median progression-free survival of 5.9 months, and median overall survival of 26.6 months. The safety profile improved with lurbinectedin dose adjustment to body surface area. The most common nonhematologic adverse events seen at 3.5 mg/m² were nausea (74%; grade 3, 5%) and fatigue (74%; grade 3, 21%). Neutropenia was the most common severe hematologic adverse event (grade 3, 47%; grade 4, 10%). Exome sequencing showed mutations in genes related to the nucleotide excision repair pathway in four of seven tumors at primary or acquired resistance and in one patient with short-term stable disease. In vivo, sensitivity to cisplatin and lurbinectedin was evidenced in lurbinectedin-resistant (one of two) and cisplatin-resistant (two of three) patient-derived xenografts.

CONCLUSION

Lurbinectedin showed noteworthy activity in patients with BRCA1/2 mutations. Response and survival was notable in those with BRCA2 mutations. Additional clinical development in this subset of patients with metastatic breast cancer is warranted.

Multicenter Phase II Study of Lurbinectedin in BRCA-Mutated and Unselected Metastatic Advanced Breast Cancer and Biomarker Assessment Substudy

Purpose

This multicenter phase II trial evaluated lurbinectedin (PM01183), a selective inhibitor of active transcription of protein-coding genes, in patients with metastatic breast cancer. A unicenter translational substudy assessed potential mechanisms of lurbinectedin resistance.

Patients and Methods

Two arms were evaluated according to germline BRCA1/2 status: BRCA1/2 mutated (arm A; n = 54) and unselected (BRCA1/2 wild-type or unknown status; arm B; n = 35). Lurbinectedin starting dose was a 7-mg flat dose and later, 3.5 mg/m² in arm A. The primary end point was objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST). The translational substudy of resistance mechanisms included exome sequencing (n = 13) and in vivo experiments with patient-derived xenografts (n = 11) from BRCA1/2-mutated tumors.

Results

ORR was 41% (95% CI, 28% to 55%) in arm A and 9% (95% CI, 2% to 24%) in arm B. In arm A, median progression-free survival was 4.6 months (95% CI, 3.0 to 6.0 months), and median overall survival was 20.0 months (95% CI, 11.8 to 26.6 months). Patients with BRCA2 mutations showed an ORR of 61%, median progression-free survival of 5.9 months, and median overall survival of 26.6 months. The safety profile improved with lurbinectedin dose adjustment to body surface area. The most common nonhematologic adverse events seen at 3.5 mg/m² were nausea (74%; grade 3, 5%) and fatigue (74%; grade 3, 21%). Neutropenia was the most common severe hematologic adverse event (grade 3, 47%; grade 4, 10%). Exome sequencing showed mutations in genes related to the nucleotide excision repair pathway in four of seven tumors at primary or acquired resistance and in one patient with short-term stable disease. In vivo, sensitivity to cisplatin and lurbinectedin was evidenced in lurbinectedin-resistant (one of two) and cisplatin-resistant (two of three) patient-derived xenografts.

Conclusion

Lurbinectedin showed noteworthy activity in patients with BRCA1/2 mutations. Response and survival was notable in those with BRCA2 mutations. Additional clinical development in this subset of patients with metastatic breast cancer is warranted.

Abstract P3-09-08: Overeating and breast cancer risk by pathologic subtypes: EpiGEICAM study

Introduction: It has been reported that overeating may be the greatest avoidable cause of cancer in nonsmokers and obesity increases postmenopausal breast cancer (BC) risk. Calorie restriction reduces BC incidence in experimental animals, but the evidence in humans is more limited. This study analyzes the association between female BC risk and excessive or restricted calorie consumption in Spain.

Methods: EpiGEICAM is a multicenter case-control study including 1017 matched pairs (age & town) of incident BC cases and healthy controls in 14 regions in Spain. Participants filled a structured questionnaire. Average calorie intake (cals) during the 5 years previous to diagnosis (cases) or interview (controls) was estimated using a validated 117-item semiquantitative food-frequency questionnaire. Expected calorie intake (cals_exp) was calculated from a linear regression model taking into account the basal metabolic rate (Sabounchi's meta-regression) and the amount of physical activity performed by each woman (5 categories). For each woman the prediction interval (99%) of cals_exp was used to consider her calorie intake as “normal” (NCI) (cals inside this interval –the reference group-), “excesive” (ECI) (cals&gt;upper limit of the interval) or “restricted” (RCI) (cals&lt;lower limit of the interval). The association of ECI and RCI with BC, overall and by pathologic subtype (luminal (ER+ and/or PR+ with HER2-), HER2+ and triple negative), was evaluated using conditional and multinomial logistic regression models, adjusted for age and region (multinomial models), education, body mass index (BMI), smoking, age at menarche & at first birth, menopausal status, previous history of benign breast disease, family history of BC, hormonal replacement therapy (HRT), physical activity and two scores reflecting the participant's adherence to Mediterranean and Western dietary patterns.

Results: After excluding participants with extreme calorie intake, 973 case-control pairs were considered. Average number of calories was higher in BC cases (1990 kcals) than controls (1897 kcals) P=0.001). Women with RCI (cals&lt;80% of the predicted limit) had lower BC risk (OR=0.52, P=0.001), being this effect more marked in premenopausal women (OR=0.36; Pheterogeneity=0.001). On the contrary, women with ECI (cals&gt;40% of the predicted limit) showed increased BC risk (OR=1.92; P=0.001), being this effect stronger in postmenopausal women (OR=2.81; Pheterogenity=0.001). By pathologic subtypes, no statistically significant differences were observed, but ECI (over 40%) was strongly associated with HER2+ tumors (OR=2.05, P=0.021). No differences in the effect of ECI or RCI were observed by levels of BMI, tobacco or HRT.

Conclusion: After taking BMI into account, excessive energy intake increases BC risk, while relative caloric restriction seems to have a protective effect. Moderate calorie restriction, in combination with regular physical activity, could be a good strategy for BC prevention.

Funding:Scientific Foundation of the Spanish Association Against Cancer (AECC), SEOM, FECMA, Cerveza y Salud Foundation, FIS CD110/00018

Citation Format: Pollán M, Castelló A, Martín M, Ruiz A, Casas AM, Baena JM, Antolin S, Ramos M, Garcia-Saénz JA, Muñoz M, Lluch A, de Juan A, Jara C, Sánchez Rovira P, Antón A, Chacón JI, Arcusa A, Jimeno MA, Bezares S, Carrasco E, Pérez-Gómez B, Lope V. Overeating and breast cancer risk by pathologic subtypes: EpiGEICAM study [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 P3-09-08.

Abstract PD3-6: ConvertHER: Evolution of genomic alterations from primary to metastatic breast cancer

Background: Changes in breast cancer receptor status over disease progression and treatment have been described to a point that could alter response to therapy. There is growing interest in delivering biomarker/genomically-based targeted therapies. We aimed to determine the concordance of genomic alterations between primary (P) and metastatic (M) breast cancer in a prospective collection study.

Methods: Targeted capture and next-generation sequencing was performed on formalin-fixed paraffin-embedded (FFPE) samples, profiling 202 cancer relevant genes in 61 pairs (primary and corresponding recurrence/metastasis). Tumors were classified at baseline as [hormone receptor (HR)+/HER2-, HR+/HER2+, HER-/HER2+, and triple negative breast cancer (TNBC)]. We aligned data to human reference assembly hg19 using Burrows-Wheeler Aligner's (BWA) and removed duplicated reads. We identified somatic mutations variants and called copy number alterations (CNA) using an algorithm which reports gain or loss status of each exon. Alterations potentially targetable with established or investigational therapeutics were considered "actionable."

Results: Of the 61 cases, 15% changed breast cancer subtype. Of 747 mutations detected in 156 genes, 309 (41%) were discordant. Median number of mutations were 10 (range 6-11) in P and 8 (range 6-10) in M. Most common mutations occurred at NOTCH2, PCLO, MAP3K1, MLL3, NOTCH4, CRIPAK, TP53, PIK3CACSMD1, and FLG. Mutations were less common in HR-/HER2+ tumors in both P and M. Mutation discordance was not different in cases of changed breast cancer subtype (P=.31). Of 986 CNA detected in 173 genes, 758 (77%) were discordant. There was an increased frequency of EGFR1, ERBB2, FGFR3, CRIPAK, MEN1 and WT1 amplifications in M. CNA were less common in HR-/HER2+ tumors in both P and M. CNA discordances were more common in cases of changed breast cancer subtype (P&lt;.0001) and driven by HER2- tumors. Fifty-eight (95%) patients had actionable alterations that could inform targeted treatment options.

Conclusion: Deep targeted exome sequencing of cancer-related genes revealed potentially targeted alterations. We found 41% and 77% mutation and CNA discordance between P and M. CNA were more common when breast cancer subtype changed.

Citation Format: Ana Maria Gonzalez-Angulo, Ana Lluch, Agda K Eterovic, Angel Guerrero, Xiaofeng Zheng, Ramon Perez, Shuying Liu, José I Chacón, Ken Chen, Silvia Antolin, Gordon B Mills, Jaime Ferrer, Octavio Burgues, Begona Bermejo, Elia Munoz, Rosalia Caballero, Eva Carrasco, Eduardo Martinez, Funda Meric-Bernstam. ConvertHER: Evolution of genomic alterations from primary to metastatic breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PD3-6.

Abstract OT1-1-06: A phase I study of LDE225 in combination with docetaxel in patients with triple negative (TN) advanced breast cancer (ABC): GEICAM/2012-12 (EDALINE study)

Background: LDE225 is a potent and selective oral inhibitor of Smo, a key component of the hedgehog (Hh) signaling pathway. Up-regulation of the Hh pathway is implicated in the genesis of a wide range of tumors including triple negative breast cancer. Here we report an ongoing phase I study exploring the combination of LDE225 with docetaxel in TN ABC patients to identify the Maximum Tolerated Dose (MTD) and the Recommended Phase II Dose (RP2D) (ClinicalTrials.gov Identifier: NCT02027376).

Trial Design: Eligibility criteria include patients with TN ABC candidates to receive treatment with docetaxel that have received a maximum of 3 prior chemotherapy regimens. Those patients with CNS involvement are also candidates if treated and clinically stable. Treatment consists of 21-day cycles with docetaxel 75mg/m2 on day 1, every 21 day and LDE225 once daily. We use a standard 3+3 design in sequential cohorts (3 dose levels (DL) of LDE225: 400mg once daily (DL1), 600mg once daily (DL2), 800mg once daily (DL3); and a DL-1: LDE225 400mg once daily and docetaxel 60mg/m2 every three weeks). The primary endpoint is the MTD and RP2D of the combination; secondary endpoints include evaluation of safety and tolerability, in addition to pharmacodynamic (PD) and pharmacokinetic (PK) studies. Patients are treated until radiologic or symptomatic progression or unacceptable toxicity occurs. PK will be performed to evaluate whether LDE225 influences the pharmacology of docetaxel. PD assessments include Hg gene expression signature associated to pathway activation in tumor samples and changes in Smo related biomarkers in skin and blood correlative samples. Efficacy will be measured in terms of time to progression and objective response rate. A minimum of 9 and a maximum of 18 patients will be included in this phase I. The study is approved by ERBs and Competent Authority and already recruiting patients (two patients included in DL1).

Citation Format: Miguel Martin, Manuel Ruiz-Borrego, José M Trigo, Silvia Antolin, Jose A Garcia-Saenz, Andres Hernando, Alberto Ocaña, Federico Rojo, Sara Lopez-Tarruella, Jesus Corral, Nuria Ribelles, Lourdes Calvo, Fernando Moreno, Rosalia Caballero, Eva Carrasco. A phase I study of LDE225 in combination with docetaxel in patients with triple negative (TN) advanced breast cancer (ABC): GEICAM/2012-12 (EDALINE study) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr OT1-1-06.

Abstract P3-13-01: Lurbinectedin (PM01183) activity in BRCA1/2-associated or unselected metastatic breast cancer. Interim results of an ongoing phase II trial

Background: Metastatic breast cancer (MBC) is a clinically heterogeneous disease in which selective approaches are needed to identify patients (pts) who will benefit the most from available therapies and avoid unnecessary toxicities.

Lurbinectedin (PM01183) is a new anticancer drug that binds to the DNA minor groove inducing double-strand breaks and blocking transcription. It has significant in vitro and in vivo antitumor activity, particularly in breast cancer models. PM01183 is more active against homologous recombination-deficient cell lines. Hence, MBC pts with deleterious germline BRCA mutations might be more sensitive to PM01183 than those with sporadic tumors.

PM1183 activity was shown in different tumor types in clinical trials, especially in pts with platinum-resistant ovarian cancer (objective response rate [ORR]: 30%).

Methods: MBC pts &lt; 75-years-old with ductal or lobular carcinoma pretreated with ≤ 3 chemotherapy regimens for MBC, measurable disease per RECIST v1.1, performance status (PS) ≤1 and adequate major organ function are being treated with PM01183 7.0 mg flat dose i.v. every 3 weeks.

The primary aim is to evaluate the clinical efficacy of PM01183 in two cohorts of MBC pts: cohort A: BRCA+ (known germline BRCA1/2 mutation) and cohort B: unselected (BRCA1/2 wild type or unknown mutation status).

The primary endpoint is confirmed ORR by RECIST v1.1. A futility analysis was planned when 20 and 30 pts were recruited in cohort A and B, respectively. If at least 4 pts in cohort A and 3 pts in cohort B, achieve a response, recruitment in that cohort will continue up to 53 and 64 total pts, respectively.

Results: As of June 2014, 56 pts had been enrolled. Cohort A/B (n: 21/35): Median age 40/52-years-old; Cohort A(%)/B(%): PS 0: 48/66; &gt;2 metastatic sites: 58/40; most common sites of metastasis: lymph node 79/33, liver 48/60 and bone 42/48; triple negative: 57/46; hormonal receptor +: 38/49; prior anthracyclines: 95/91, taxanes: 100/94, platinum: 52/26, PARPi: 29/0; cohort A: BRCA 1/2 (%): 52/48.

Cohort A-BRCA 1/2+ (n=21)Cohort B-unselected (n=35)Median cycles (range)4 (1-20)3 (1-14)Best overall response(n= 17 evaluable)(n= 34 evaluable)CR1 (6%)0PR6 (35%)3 (9%)SD6 (35%)16 (47%)PD4 (24%)15 (44%)ORR (95%CI)41% (18-67%)9% (1.9-23.7%)Median duration of response Monts (95%CI)5.0 (0.1-12.8)3.3 (1.4-5.1)

In an exploratory analysis, ORR in cohort A was higher in PARPi naïve pts: 64% (7/11 pts).

Grade (G) 3-4 related adverse events occurred in &gt;5% pts were myelosuppression (neutropenia 69%, febrile neutropenia 7%, thrombocytopenia 14%); G3 fatigue 7%, transient transaminase increase 19% (G4: 2%), nausea 6% and dyspnea 6% (3 pts, 2 of them due to pneumonitis). One patient with massive liver involvement and impaired function died on C1D4 due to multiorgan failure possibly related to the study drug.

Conclusions: PM01183 has promising activity in pretreated MBC pts with BRCA mutation. Safety profile appears to be mostly predictable and with non-cumulative toxicity. Treatment-related neutropenia was manageable with G-CSF and/or dose reduction.

After futility analysis, targeted activity has been met in cohort A (BRCA+), and recruitment will continue up to 53 evaluable BRCA+ pts.

Citation Format: Judit Balmaña, Cristina Cruz, Judy Garber, Jose A Perez Fidalgo, Ana Lluch, Nadine Tung, Silvia Antolin, Cristian Fernandez, Carmen Kahatt, Sergio Szyldergemajn, Arturo Soto Matos, Sonia Extremera, Jose Baselga, Steven J Isakoff. Lurbinectedin (PM01183) activity in BRCA1/2-associated or unselected metastatic breast cancer. Interim results of an ongoing phase II trial [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-13-01.

Abstract P3-14-15: Nabrax: Neoadjuvant therapy of breast cancer with weekly nab-paclitaxel: Final safety of GEICAM 2011-02

Aims: nab-paclitaxel is an innovative chemotherapy that consists of nano-particles of human serum albumin bound paclitaxel. It exploits the role of albumin as the natural carrier of hydrophobic molecules in human to increase paclitaxel delivery to tumor cells. Weekly nab-paclitaxel showed a superior efficacy compared to every 3-weeks docetaxel in a randomized phase II study in metastatic breast cancer (Gradishar JCO 2009, Clin. Breast Cancer 2012). This single arm phase II trial has been designed to evaluate the activity and safety of weekly nab-paclitaxel as neoadjuvant treatment of early stage breast cancer patients with positive estrogen receptors and negative HER2.

Methods: Stage II-III patients were included and treated with nab-paclitaxel weekly at a dose of 150 mg/m2 on days 1, 8 and 15 every 4 weeks for 4 cycles. Following chemotherapy, patients undergo surgery and adjuvant therapy (with radiation, chemo and endocrine therapy) under the investigator criteria. The primary objective is to determine the residual cancer burden class III as measured by the Symmans criteria (JCO 25:4422,2007). Secondary objectives include pathological complete response, overall response, invasive disease free survival, safety and potential correlative biomarkers.

Results: Eighty-three patients have been recruited in the study in 13 Spanish institutions. Here we report safety data from 77 patients. Median age was 48 years, 62% were postmenopausal and 94% had ECOG PS 0; most patients were stage II (23% IIa and 36% IIb). A total of 259 cycles have been administered to date; 47 patients completed 4 cycles as planned, 5 patients discontinued treatment early (due to grade 2-3 sensory neuropathy in 4 patients), the remaining patients are still under treatment. The treatment was delayed in 8.1% of patients; nab-paclitaxel doses were omitted and reduced in 3.9% and 9.7% of cycles respectively, for a relative dose intensity of nab-paclitaxel of 97.3%. The most frequent reasons for dose modifications were neutropenia (5.4%) and neuropathy (2.7%). The main grade 2/3 adverse events are described in table 1.

Table 1Related adverse events.Per patient (N = 74)Per Cycle (N = 259)NCI-CTCAE vs 4.0. (&gt;5% grade 2-4)Grade 2, N (%)Grade 3, N (%)Grade 2, N (%)Grade 3, N (%)Leukopenia6 (8.1)1 (1.4)11 (4.2)1 (0.4)Neutropenia17(23)7 (9.5)30 (11.6)9 (3.5)Alopecia47(63.5)—121 (46.7)—Fatigue11 (14.9)2 (2.7)17 (6.6)2 (0.8)Neuropathy: Sensory17 (23)2 (2.7)25(9.6)5 (1.9)Musculoskeletal Pain11 (14.9)0 (0)13 (5.0)0 (0)

Conclusions: Neoadjuvant therapy with weekly nab-paclitaxel at dose of 150 mg/m2 on days 1, 8 and 15 every 4 weeks was well tolerated. Final safety data for the entire treated patients will be mature and presented at the meeting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-14-15.

P2-12-17: Prospective Evaluation of the Conversion Rate of HER2, ER and PR between Primary Tumors and Corresponding Metastases. CONVERTHER/GEICAM 2009–03 Study

Introduction: A substantial number of small studies, most retrospective, have shown variable degrees of discordance in HER2, ER and PR expression between primary and metastatic breast cancer. This may have prognostic and therapeutic implications. These discordances could be triggered by tumor somatic mutations, intratumoral heterogeneity, or technical issues with receptor assayes. In this prospective study, we centrally analyzed and determined the changes in receptor status between primary tumor and corresponding metastases.

Methods: In 32 Spanish hospitals, patients where primary tumor sample was available, were prospectively included prior to the biopsy of the presumably metastatic lesion. Determinations of ER and PR status (assessed by immuhistochemistry [IHC]) and HER2 status (IHC and FISH) were centrally and blindly performed in both primary tumor and metastases. Concordance rate between local laboratories and central laboratory receptor determinations were analyzed. We also determined whether the biopsy results modified the oncologist initial treatment strategy.

Results: A total of 236 patients were included. To today, 183 paired cases were centrally evaluated. Patients in first recurrence were 65% and the mean age was 57.2 years. Biopsy samples were taken from locoregional recurrence (25%), liver metastases (28%), bone metastases (11%), lung metastases (7%) and other locations (29%). In 6.6% of the biopsies normal tissue, benign lesion or secondary malignant neoplasm were seen. The changes in HER2, ER and PR were 17%, 26% and 35% (local lab) and 4%, 12% and 26% (central lab), respectively; and were independent of treatment given or biopsy localization. Concordance rate in HER2, ER and PR between local and central determination were 83%, 92% and 78% (kappa index 0.58, 0.80 and 0.55), respectively. Changes in receptor status lead to a modification in medical management in 16% of patients.

Conclusions: A remarkable discordance in receptor status, especially in the hormonal receptors, was found between primary tumor and metastases that implies a change in medical management in 16% of patients. These discordances were reduced but remained after performing in a high-quality central laboratory, so that they could only be partly explained by technical discrepancies in receptor assessments.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-17.