Updated overall survival from the MONALEESA-3 trial in postmenopausal women with HR+/HER2- advanced breast cancer receiving first-line ribociclib plus fulvestrant

BACKGROUND

The phase III MONALEESA-3 trial included first- (1L) and second-line (2L) patients and demonstrated a significant overall survival (OS) benefit for ribociclib + fulvestrant in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) in the final protocol-specified and exploratory (longer follow-up) OS analyses. At the time of these analyses, the full OS benefit of 1L ribociclib was not completely characterized because the median OS (mOS) was not reached. As CDK4/6 inhibitor (CDK4/6i) + endocrine therapy (ET) is now a preferred option for 1L HR+/HER2- ABC, we report an exploratory analysis (median follow-up, 70.8 months; 14.5 months longer than the prior analysis) to fully elucidate the OS benefit in the MONALEESA-3 1L population.

METHODS

Postmenopausal patients with HR+/HER2- ABC were randomized 2:1 to 1L/2L fulvestrant + ribociclib or placebo. OS in 1L patients (de novo disease or relapse > 12 months from completion of [neo]adjuvant ET) was assessed by Cox proportional hazards model and Kaplan-Meier methods. Progression-free survival 2 (PFS2) and chemotherapy-free survival (CFS) were analyzed. MONALEESA-3 is registered with ClinicalTrials.gov (NCT02422615).

RESULTS

At data cutoff (January 12, 2022; median follow-up time, 70.8 months), mOS was 67.6 versus 51.8 months with 1L ribociclib versus placebo (hazard ratio (HR) 0.67; 95% CI 0.50-0.90); 16.5% and 8.6% of ribociclib and placebo patients, respectively, were still receiving treatment. PFS2 (HR 0.64) and CFS (HR 0.62) favored ribociclib versus placebo. Among those who discontinued treatment, 16.7% and 35.0% on ribociclib or placebo, respectively, received a subsequent CDK4/6i. No new safety signals were observed.

CONCLUSIONS

This analysis of MONALEESA-3 reports the longest mOS thus far (67.6 months) for 1L patients in a phase III ABC trial. These results in a 1L population show that the OS benefit of ribociclib was maintained through extended follow-up, further supporting its use in HR+/HER2- ABC.

The pan-immune-inflammation value is associated with clinical outcomes in patients with advanced TNBC treated with first-line, platinum-based chemotherapy: an institutional retrospective analysis

Background

Advanced triple-negative breast cancer (aTNBC) has a poor prognosis; thus, there is a need to identify novel biomarkers to guide future research and improve clinical outcomes.

Objectives

We tested the prognostic ability of an emerging, complete blood count (CBC)-based inflammatory biomarker, the pan-immune-inflammation value (PIV), in patients with aTNBC treated with first-line, platinum-based chemotherapy.

Design

This was a retrospective, monocentric, observational study.

Methods

We included consecutive aTNBC patients treated with platinum-based, first-line chemotherapy at our Institution, and for whom baseline (C1) CBC data were available. We collected CBC data early on-treatment, when available. PIV was calculated as: (neutrophil count × platelet count × monocyte count)/lymphocyte count. Patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (aBC) were included in a control, non-TNBC cohort.

Results

A total of 78 aTNBC patients were included. When evaluated as a continuous variable, PIV-C1 was associated with worse overall survival (OS; p < 0.001) and progression-free survival (PFS; p < 0.001). On the other hand, when PIV-C1 was assessed on the basis of its quantile distribution, patients with 'high PIV-C1' experienced worse OS [adjusted hazard ratio (HR): 4.46, 95% confidence interval (CI): 2.22-8.99; adjusted p < 0.001] and PFS (adjusted HR: 2.03, 95% CI: 1.08-3.80; adjusted p = 0.027) when compared to patients with 'low PIV-C1'. Higher PIV-C1 was also associated with primary resistance to chemotherapy. Similarly, a higher PIV calculated from CBC at C2D1 (PIV-C2) was associated with worse survival outcomes. We also created a PIV-based score combining information about both PIV-C1 and PIV-C2 and allowing the stratification of patients at low, intermediate, and high risk of death. No association was observed between PIV-C1 and clinical outcomes of HR+/HER2- aBC patients.

Conclusion

PIV has a promising prognostic discrimination ability in aTNBC patients treated with first-line, platinum-based chemotherapy. Both baseline and early on-treatment PIV are associated with clinical outcomes and may be exploited for creating PIV-based risk classifiers if further validated.

Circulating tumor DNA (ctDNA) and serum thymidine kinase 1 activity (TKa) matched dynamics in patients (pts) with hormone receptor–positive (HR+), human epidermal growth factor 2–negative (HER2-) advanced breast cancer (ABC) treated in first-line (1L) with ribociclib (RIB) and letrozole (LET) in the BioItaLEE trial

1012

Background: Independent early dynamic assessment (baseline [D0] and day 15 of first cycle [D15]) of both TKa and ctDNA was prognostic and predictive in pts with HR+, HER2− ABC treated with RIB+LET enrolled in the BioItaLEE trial (NCT03439046). Here we performed a combined analysis of these two biomarkers. Methods: 287 pts were enrolled in the study. Overall, early dynamics were assessable for both biomarkers in 241/287 pts (84.0%). Methods applied for ctDNA and TKa evaluation were previously reported. For ctDNA, samples were defined as wild type (WT) if no mutations were observed at D0 and D15, ctDNA positive (+) if with or negative (-) if without a primary target mutation at D15. Samples were TKa+ or TKa- if TKa levels were above or below the limit of detection at D15. According to ctDNA and TKa pts were classified as: WT/TKa-, WT/TKa+, ctDNA-/TKa-, ctDNA-/TKa+, ctDNA+/TKa- and ctDNA+/TKa+ and then divided into 3 main study groups (GRs) WT/TKa- (GR1, n = 126), WT/TKa+, ctDNA-/TKa-, ctDNA-/TKa+, ctDNA+/TKa- (GR2, n = 96) and ctDNA+/TKa+ (GR3, n = 19). The association between biomarkers and PFS (progression-free survival) was estimated using Kaplan-Meier analysis and multivariate Cox models with 95% confidence intervals (CIs) adjusted for clinical variables. Results: Median follow-up was 26.9 months. In multivariate Cox models both TKa dynamics and mutational tumor burden at D15 were independently predictive of PFS. Hazard ratios (HRs) were 0.37 (95% CI: 0.23-0.60; p < 0.0001) for WT vs ctDNA+ and 0.56 (95% CI: 0.32-1.00; p = 0.0506) for ctDNA- vs ctDNA+. For TKa, HR was 0.49 (95% CI: 0.30-0.80; p = 0.0040) in TKa- vs TKa+. Interestingly combining the two variables further improve prediction of outcome. HRs for TKa- vs TKa+ were 0.17 (95% CI: 0.09-0.32; p < 0.0001), 0.28 (95% CI: 0.13-0.59; p = 0.0009) and 0.44 (95% CI: 0.23-0.86; p = 0.0169) in WT, ctDNA- and ctDNA+ pts, respectively. Considering the 3 study GRs, median PFSs (95% CI) were not reached (27.89, NE), 19.58 (13.83, 23.39) and 6.65 (2.83, 12.16) months in GR1, GR2 and GR3, respectively, p < 0.001. At multivariate Cox models, HRs of GR1 and GR2 compared with GR3 were 0.17 (95% CI: 0.09-0.32; p < 0.0001) and 0.37 (95% CI: 0.20-0.67; p = 0.001) respectively. Conclusions: These findings suggest that combining the early dynamic assessment of both ctDNA and TKa may improve outcome prediction in pts treated with RIB+LET. Pts with ctDNA+/TKa+ are strongly enriched for non-responders. TKa and ctDNA capture different features of tumor biological activity and their combination warrants further evaluation in relation to other treatments, settings, and diseases. Clinical trial information: NCT03439046.

Early stage breast cancer follow-up in real-world clinical practice: the added value of cell free circulating tumor DNA

Purpose

Physical examinations and annual mammography (minimal follow-up) are as effective as laboratory/imaging tests (intensive follow-up) in detecting breast cancer (BC) recurrence. This statement is now challenged by the availability of new diagnostic tools for asymptomatic cases. Herein, we analyzed current practices and circulating tumor DNA (ctDNA) in monitoring high-risk BC patients treated with curative intent in a comprehensive cancer center.

Patients and methods

Forty-two consecutive triple negative BC patients undergoing neoadjuvant therapy and surgery were prospectively enrolled. Data from plasma samples and surveillance procedures were analyzed to report the diagnostic pattern of relapsed cases, i.e., by symptoms, follow-up procedures and ctDNA.

Results

Besides minimal follow-up, 97% and 79% of patients had at least 1 non-recommended imaging and laboratory tests for surveillance purposes. During a median follow-up of 5.1(IQR, 4.1–5.9) years, 13 events occurred (1 contralateral BC, 1 loco-regional recurrence, 10 metastases, and 1 death). Five recurrent cases were diagnosed by intensive follow-up, 5 by symptoms, and 2 incidentally. ctDNA antedated disseminated disease in all evaluable cases excepted two with bone-only and single liver metastases. The mean time from ctDNA detection to suspicious findings at follow-up imaging was 3.81(SD, 2.68), and to definitive recurrence diagnosis 8(SD, 2.98) months. ctDNA was undetectable in the absence of disease and in two suspected cases not subsequently confirmed.

Conclusions

Some relapses are still symptomatic despite the extensive use of intensive follow-up. ctDNA is a specific test, sensitive enough to detect recurrence before other methods, suitable for clarifying equivocal imaging, and exploitable for salvage therapy in asymptomatic BC survivors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-03990-7.

Gene signatures of circulating breast cancer cell models are a source of novel molecular determinants of metastasis and improve circulating tumor cell detection in patients

Background

Progression to stage IV disease remains the main cause of breast cancer-related deaths. Increasing knowledge on the hematogenous phase of metastasis is key for exploiting the entire window of opportunity to interfere with early dissemination and to achieve a more effective disease control. Recent evidence suggests that circulating tumor cells (CTCs) possess diverse adaptive mechanisms to survive in blood and eventually metastasize, encouraging research into CTC-directed therapies.

Methods

On the hypothesis that the distinguishing molecular features of CTCs reveal useful information on metastasis biology and disease outcome, we compared the transcriptome of CTCs, primary tumors, lymph-node and lung metastases of the MDA-MB-231 xenograft model, and assessed the biological role of a panel of selected genes, by in vitro and in vivo functional assays, and their clinical significance in M0 and M+ breast cancer patients.

Results

We found that hematogenous dissemination is governed by a transcriptional program and identified a CTC signature that includes 192 up-regulated genes, mainly related to cell plasticity and adaptation, and 282 down-regulated genes, involved in chromatin remodeling and transcription. Among genes up-regulated in CTCs, FADS3 was found to increases cell membrane fluidity and promote hematogenous diffusion and lung metastasis formation. TFF3 was observed to be associated with a subset of CTCs with epithelial-like features in the experimental model and in a cohort of 44 breast cancer patients, and to play a role in cell migration, invasion and blood-borne dissemination. The analysis of clinical samples with a panel of CTC-specific genes (ADPRHL1, ELF3, FCF1, TFF1 and TFF3) considerably improved CTC detection as compared with epithelial and tumor-associated markers both in M0 and stage IV patients, and CTC kinetics informed disease relapse in the neoadjuvant setting.

Conclusions

Our findings provide evidence on the potential of a CTC-specific molecular profile as source of metastasis-relevant genes in breast cancer experimental models and in patients. Thanks to transcriptome analysis we generated a novel CTC signature in the MDA-MB-231 xenograft model, adding a new piece to the current knowledge on the key players that orchestrate tumor cell hematogenous dissemination and breast cancer metastasis, and expanding the list of CTC-related biomarkers for future validation studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02259-8.

The TRAR gene classifier to predict response to neoadjuvant therapy in HER2-positive and ER-positive breast cancer patients: an explorative analysis from the NeoSphere trial

As most erb-b2 receptor tyrosine kinase 2 (HER2)-positive breast cancer (BC) patients currently receive dual HER2-targeting added to neoadjuvant chemotherapy, improved methods for identifying individual response, and assisting postsurgical salvage therapy, are needed. Herein, we evaluated the 41-gene classifier trastuzumab advantage risk model (TRAR) as a predictive marker for patients enrolled in the NeoSphere trial. TRAR scores were computed from RNA of 350 pre- and 166 post-treatment tumor specimens. Overall, TRAR score was significantly associated with pathological complete response (pCR) rate independently of other predictive clinico-pathological variables. Separate analyses according to estrogen receptor (ER) status showed a significant association between TRAR score and pCR in ER-positive specimens but not in ER-negative counterparts. Among ER-positive BC patients not achieving a pCR, those with TRAR-low scores in surgical specimens showed a trend for lower distant event-free survival. In conclusion, in HER2-positive/ER-positive BC, TRAR is an independent predictor of pCR and represents a promising tool to select patients responsive to anti-HER2-based neoadjuvant therapy and to assist treatment escalation and de-escalation strategies in this setting.

Fulvestrant and trastuzumab in patients with luminal HER2-positive advanced breast cancer (ABC): an Italian real-world experience (HERMIONE 9)

PURPOSE

The most appropriate therapy for HR + /HER2-positive (HER2 +) advanced breast cancer (ABC) is a matter of debate. Co-targeting of both receptors represents an attractive strategy to overcome the cross-talk between them.

METHODS

The HERMIONE 9 is an observational retrospective multicentric study which aimed to describe the clinical outcome of patients with HR + /HER2 + ABC who received the combination of Fulvestrant (F) and Trastuzumab (T) as part of their routine treatment at 10 Italian Institutions.

RESULTS

Eighty-seven patients were included. Median age was 63 (range, 35-87) years. The median number of previous treatments was 3 (range, 0-10) and F and T were administered as ≥ 3rd line in 67 patients. Among the 86 evaluable patients, 6 (6.9%) achieved CR, 18 (20.7%) PR, and 44 (50.6%) had SD ≥ 24 weeks with an overall CBR of 78.2%. At a median follow-up of 33.6 months, mPFS of the entire cohort was 12.9 months (range, 2.47-128.67). No difference was observed in mPFS between patients treated after progression or as maintenance therapy (mPFS 12.9 and 13.9 months in 64 and 23 patients, respectively), neither considering the number of previous treatment lines (≤ 3 or < 3).

CONCLUSION

The combination of F and T was active in this cohort at poor prognosis and deserves further investigations possibly in combination with pertuzumab in patients with high ER expression.

Updated overall survival (OS) results from the phase III MONALEESA-3 trial of postmenopausal patients (pts) with HR+/HER2- advanced breast cancer (ABC) treated with fulvestrant (FUL) ± ribociclib (RIB)

1001

Background: The Phase III MONALEESA-3 trial (NCT02422615) previously demonstrated a statistically significant improvement in OS with RIB, a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i), plus FUL compared with placebo (PBO) plus FUL as first-line (1L) or second-line (2L) treatment in postmenopausal pts with HR+/HER2− ABC (median, not reached vs 40.0 mo; hazard ratio [HR], 0.72; 95% CI, 0.57-0.92, P =.00455). This analysis was final per the protocol; following the unblinding of the study, pts still on study treatment in the PBO arm were allowed to cross over to the RIB arm. We report an exploratory analysis of OS after an additional median 16.9 mo of follow-up, allowing for further characterization of long-term survival benefits of RIB. Methods: Postmenopausal pts with HR+/HER2− ABC were randomized 2:1 to receive RIB + FUL or PBO + FUL in 1L and 2L settings. Updated OS was evaluated by Cox proportional hazards model and summarized using Kaplan-Meier methods. Additional postprogression endpoints such as progression-free survival 2 (PFS2), time to chemotherapy (CT), and CT-free survival were also evaluated and summarized. Results: At the data cutoff (Oct 30, 2020), the median follow-up was 56.3 mo (min, 52.7 mo) and 68 (14.0%) and 21 (8.7%) patients were still on treatment in the RIB vs PBO arms, respectively. With this extended follow-up, RIB + FUL continued to demonstrate an OS benefit vs PBO + FUL (median, 53.7 vs 41.5 mo; HR, 0.73; 95% CI, 0.59-0.90). RIB + FUL had prolonged OS vs PBO + FUL in the 1L (median, not reached vs 51.8 mo; HR, 0.64; 95% CI, 0.46-0.88) and 2L subgroups (median, 39.7 vs 33.7 mo; HR, 0.78; 95% CI, 0.59-1.04). Subgroup analyses also showed a consistent OS benefit compared with the intent-to-treat (ITT) population for most subgroups. PFS2, time to CT, and CT-free survival for the ITT population favored RIB + FUL (Table). Among pts who discontinued study treatment, 81.9% and 86.4% received a next-line subsequent antineoplastic therapy, while 14.0% and 30.0% received a CDK4/6i as any subsequent line in the RIB vs PBO arms, respectively. No new safety signals were observed. Conclusions: The previously demonstrated robust and clinically meaningful OS benefit with RIB + FUL compared with PBO + FUL was maintained after almost 5 years of follow-up in postmenopausal pts with HR+/HER2− ABC. The OS benefit of RIB was observed in the 1L and 2L subgroups, which further supports the use of RIB in these populations. The results also demonstrated a significant delay in the use of subsequent CT with RIB vs PBO. Clinical trial information: NCT02422615 .[Table: see text]

Blood-based genomics of triple-negative breast cancer progression in patients treated with neoadjuvant chemotherapy

Background

As neoadjuvant chemotherapy (NAC) is increasingly used in triple-negative breast cancer (TNBC), we investigated the value of circulating tumor DNA (ctDNA) for patient monitoring prior, during, and after NAC, and circulating tumor cells (CTCs) for disease characterization at clinical progression.

Materials and methods

Forty-two TNBC patients undergoing NAC were prospectively enrolled. Primary tumor mutations identified by targeted-gene sequencing were validated and tracked in 168 plasma samples longitudinally collected at multiple time-points by droplet digital polymerase chain reaction. At progression, plasma DNA underwent direct targeted-gene assay, and CTCs were collected and analyzed for copy number alterations (CNAs) by low-pass whole genome sequencing.

Results

ctDNA detection after NAC was associated with increased risk of relapse, with 2-year event-free survival estimates being 44.4% [95% confidence interval (CI) 21.4%-92.3%] versus 77.4% (95% CI 57.8%-100%). ctDNA prognostic value remained worthy even after adjusting for age, residual disease, systemic inflammatory indices, and Ki-67 [hazard ratio (HR) 1.91; 95% CI 0.51-7.08]. During follow-up, ctDNA was undetectable in non-recurrent cases with the unique exception of one showing a temporary peak over eight samples. Conversely, ctDNA was detected in 8/11 recurrent cases, and predated the clinical diagnosis up to 13 months. Notably, recurrent cases without ctDNA developed locoregional, contralateral, and bone-only disease. At clinical progression, CTCs presented chromosome 10 and 21q CNAs whose network analysis showed connected modules including HER/PI3K/Ras/JAK signaling and immune response.

Conclusion

ctDNA is not only associated with but is also predictive of prognosis in TNBC patients receiving NAC, and represents an exploitable tool, either alone or with CTCs, for personalized TNBC management.

•

ctDNA was detected in 77% of early-stage TNBC patients undergoing neoadjuvant chemotherapy.

•

Patients with still detectable ctDNA after NAC were more than twice as likely to relapse as those with undetectable levels.

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Detection of ctDNA during follow-up antedated clinical overt metastases up to 13 months.

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ctDNA was undetectable in all but one non-recurrent patient with a temporary peak in only 1 of 8 samples tested.

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CTCs of progressing cases lacked epithelial surface markers and showed therapeutically exploitable molecular features.

Early Changes of the Standardized Uptake Values (SUVmax) Predict the Efficacy of Everolimus-Exemestane in Patients with Hormone Receptor-Positive Metastatic Breast Cancer

Background: The mTORC1 inhibitor everolimus has been approved in combination with the aromatase inhibitor exemestane for the treatment of hormone receptor-positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (HR+ mBC) progressing on prior therapy with a non-steroidal aromatase inhibitor. To date, no predictive biomarkers of tumor sensitivity/resistance for everolimus-based treatments have been identified. We hypothesized that precocious changes in the Standardized Uptake Volume (∆SUV%), as assessed by ¹⁸F-Fluorodeoxyglucosepositron-emission tomography (¹⁸F-FDG PET/CT), may be a marker of everolimus efficacy. Methods: This was a retrospective study including 31 HR+ HER2- patients treated with everolimus and exemestane in two Italian centers between 2013 and 2018. The objective of the study was to investigate ∆SUV% as a predictive marker of everolimus antitumor efficacy. ¹⁸F-FDG PET/CT scans were performed at baseline and after three months of treatment. Patients were defined as long responders (LRs) if disease progression occurred at least 10 months after treatment initiation and long survivors (LSs) if death occurred later than 36 months after starting therapy. ROC analysis was used to determine the optimal cut-off values of ∆SUV% to distinguish LRs from non-LRs and LSs from non-LSs. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier method. Results: The SUVmax values decreased significantly from baseline to 3 months after therapy (p = 0.003). Dynamic changes of SUVmax (Delta SUV) had a higher accuracy in discriminating long-responders from non-long-responders (AUC = 0.67, Delta SUV cut-off = 28.8%) respects to its ability to identify long survivors from no-long survivors (AUC = 0.60, Delta SUV cut-off = 53.8%). Patients were divided into groups according to the Delta SUV cut-offs and survival outcomes were evaluated: patients with a decrease of ∆SUV% ≥ 28.8% had significantly better PFS (10 months-PFS: 63.2%, 95% CI: 37.9-80.4% and 16.7%, 95% CI: 2.7-41.3% respectively, p = 0.005). As regard as OS, patients with ∆SUV% ≥ 53.8% had longer OS when compared to patients with ∆SUV% < 53.8% (36 month-OS: 82.5% vs. 45.9% vs. p = 0.048). Conclusion: We found two precocious ∆SUV% thresholds capable of identifying HR+ HER2-mBC patients, which would achieve long-term benefit or long-term survival during everolimus-exemestane therapy. These results warrant further validation in prospective studies and should be integrated with molecular biomarkers related to tumor metabolism and mTORC1 signaling.

De-escalated therapy for HR+/HER2+ breast cancer patients with Ki67 response after 2-week letrozole: results of the PerELISA neoadjuvant study

BACKGROUND

In human epidermal growth factor receptor 2 (HER2+) breast cancers, neoadjuvant trials of chemotherapy plus anti-HER2 treatment consistently showed lower pathologic complete response (pCR) rates in hormone receptor (HR) positive versus negative tumors. The PerELISA study was aimed to evaluate the efficacy of a de-escalated, chemotherapy-free neoadjuvant regimen in HR+/HER2+ breast cancer patients selected on the basis of Ki67 inhibition after 2-week letrozole.

PATIENTS AND METHODS

PerELISA is a phase II, multicentric study for postmenopausal patients with HR+/HER2+ operable breast cancer. Patients received 2-week letrozole, and then underwent re-biopsy for Ki67 evaluation. Patients classified as molecular responders (Ki67 relative reduction >20% from baseline) continued letrozole and started trastuzumab-pertuzumab for five cycles. Patients classified as molecular non-responders started weekly paclitaxel for 13 weeks combined with trastuzumab-pertuzumab. Primary aim was breast and axillary pCR. According to a two-stage Simon's design, to reject the null hypothesis, at least 8/43 pCR had to be documented.

RESULTS

Sixty-four patients were enrolled, 44 were classified as molecular responders. All these patients completed the assigned treatment with letrozole-trastuzumab-pertuzumab and underwent surgery. A pCR was observed in 9/44 cases (20.5%, 95% confidence interval 11.1% to 34.5%). Among molecular non-responders, 16/17 completed treatment and underwent surgery, with pCR observed in 81.3% of the cases. PAM50 intrinsic subtype was significantly associated with Ki67 response and pCR. Among molecular responders, the pCR rate was significantly higher in HER2-enriched than in other subtypes (45.5% versus 13.8%, P = 0.042).

CONCLUSIONS

The primary end point of the study was met, by reaching the pre-specified pCRs. In patients selected using Ki67 reduction after short-term letrozole exposure, a meaningful pCR rate can be achieved without chemotherapy. PAM50 intrinsic subtyping further refines our ability to identify a subset of patients for whom chemotherapy might be spared.

EUDRACT NUMBER

2013-002662-40.

CLINICALTRIALS.GOV IDENTIFIER

NCT02411344.

The neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios predict efficacy of CDK 4/6 inhibitors in women with hormone receptor-positive/HER2-negative advanced breast cancer

e13032

Background: Cyclin-dependent kinase (CDK) 4/6 inhibitors combined with endocrine therapies (ETs) are a mainstay of treatment for patients (pts) with hormone receptor-positive advanced breast cancer (HR+ aBC). Preclinical evidence indicates that their ability to stimulate antitumor immunity may crucially contribute to their anticancer activity. The neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) reflect systemic inflammation and immune system functional status and could be associated with CDK 4/6 inhibitor efficacy in pts with HR+ aBC. Methods: A retrospective, monocentric study was performed to investigate the association between NLR or PLR, as measured at baseline and after the first three treatment cycles, and progression free survival (PFS) in HR+ aBC pts treated with CDK 4/6 inhibitors. The thresholds for NLR and PLR were defined using the maximally selected rank statistics. Cox proportional hazard model was used to evaluate the impact of these parameters on PFS at univariate and multivariable analysis. Results: We evaluated a total number of 162 pts. Of them 142 were treated with palbociclib, 17 with ribociclib and 3 with abemaciclib plus ETs between January 2017 and December 2019 at our Institution. NLR and PLR at baseline were not associated with PFS. Conversely, high NLR ( > 3) and high PLR ( > 323.6) after three treatment cycles were associated with significantly lower PFS (p = 0.011 and p = 0.013, respectively). Multivariable analysis confirmed an independent association between high NLR or PLR and lower PFS (aHR 3.66, 95% CI 1.44-9.33, p = 0.007 and aHR 2.79, 95% CI 1.36-5.70, p = 0.005, respectively). Conclusions: To the best of our knowledge this is the first study to show a significant association between high NLR or PLR values and lower PFS in HR+ aBC pts treated with CDK 4/6 inhibitors. The association was not present with baseline values but only when NLR or PLR were measured after three treatment cycles, suggesting potential immunomodulatory activity of CDK 4/6 inhibitors.

Is There Still a Role for Endocrine Therapy Alone in HR+/HER2- Advanced Breast Cancer Patients? Results from the Analysis of Two Data Sets of Patients Treated with High-Dose Fulvestrant as First-Line Therapy in the Real-World Setting: The EVA and GIM-13 AMBRA Studies

Background

Different studies suggest that fulvestrant 500 mg every 28 days (HD-FUL) could be an active treatment in HR+ advanced breast cancer (ABC) patients even treated with aromatase inhibitors in the adjuvant setting. The aim of this analysis is to describe the outcome of ABC patients treated with HD-FUL as first-line treatment in terms of median duration of treatment and the overall response rate in a real-world setting.

Methods

For the purpose of the present analysis, we considered two data sets of HR+ ABC patients collected in Italy between 2012 and 2015 (EVA and GIM-13 AMBRA studies).

Results

Eighty-one and 91 patients have been identified from the two data sets. The median age was 63 years (range 35-82) for the EVA and 57.8 years (range 35.0-82.3) for the AMBRA patients. ORRs were 23.5 and 24.3% in the whole population, 26.9% in the patients with bone only, and 21.8 and 21.4% in those with visceral metastases. The median duration of HD-FUL was 11.6 months (range 1-48) and 12.4 months (range 2.9-70.0) in the two data sets, respectively.

Conclusion

These data suggest that HD-FUL should still continue to play a significant role as first-line therapy in HR+ ABC patients.

Targeted-Gene Sequencing to Catch Triple Negative Breast Cancer Heterogeneity before and after Neoadjuvant Chemotherapy

Triple negative breast cancer (TNBC) patients not attaining pathological Complete Response (pCR) after neo-adjuvant chemotherapy (NAC) have poor prognosis. We characterized 19 patients for somatic mutations in primary tumor biopsy and residual disease (RD) at surgery by 409 cancer-related gene sequencing (IonAmpliSeqTM Comprehensive Cancer Panel). A median of four (range 1–66) genes was mutated in each primary tumor biopsy, and the most common mutated gene was TP53 followed by a long tail of low frequency mutations. There were no recurrent mutations significantly associated with pCR. However, half of patients with RD had primary tumor biopsy with mutations in genes related to the immune system compared with none of those achieving pCR. Overall, the number of mutations showed a downward trend in post- as compared to pre-NAC samples. PIK3CA was the most common altered gene after NAC. The mutational profile of TNBC during treatment as inferred from patterns of mutant allele frequencies in matched pre-and post-NAC samples showed that RD harbored alterations of cell cycle progression, PI3K/Akt/mTOR, and EGFR tyrosine kinase inhibitor-resistance pathways. Our findings support the use of targeted-gene sequencing for TNBC therapeutic development, as patients without pCR may present mutations of immune-related pathways in their primary tumor biopsy, or actionable targets in the RD.

Neoadjuvant eribulin mesylate following anthracycline and taxane in triple negative breast cancer: Results from the HOPE study

BACKGROUND

Eribulin mesylate (E) is indicated for metastatic breast cancer patients previously treated with anthracycline and taxane. We argued that E could also benefit patients eligible for neoadjuvant chemotherapy.

METHODS

Patients with primary triple negative breast cancer ≥2 cm received doxorubicin 60 mg/m2 and paclitaxel 200 mg/m2 x 4 cycles (AT) followed by E 1.4 mg/m2 x 4 cycles. Primary endpoint was pathological complete response (pCR) rate; secondary and explorative endpoints included clinical/metabolic response rates and safety, and biomarker analysis, respectively. Using a two-stage Simon design, 43 patients were to be included provided that 4 of 13 patients had achieved pCR in the first stage of the study.

RESULTS

In stage I of the study 13 women were enrolled, median age 43 years, tumor size 2-5 cm in 9/13 (69%), positive nodal status in 8/13 (61%). Main grade 3 adverse event was neutropenia (related to AT and E in 4 and 2 cases, respectively). AT followed by E induced clinical complete + partial responses in 11/13 patients (85%), pCR in 3/13 (23%). Median measurements of maximum standardized uptake value (SUVmax) resulted 13, 3, and 1.9 at baseline, after AT and E, respectively. Complete metabolic response (CMR) occurred after AT and after E in 2 and 3 cases, respectively. Notably, 2 of the 5 (40%) patients with CMR achieved pCR at surgery. Immunostaining of paired pre-/post-treatment tumor specimens showed a reduction of β-catenin, CyclinD1, Zeb-1, and c-myc expression, in the absence of N-cadherin modulation. The study was interrupted at stage I due to the lack of the required patients with pCR.

CONCLUSIONS

Despite the early study closure, preoperative E following AT showed clinical and biological activity in triple negative breast cancer patients. Furthermore, the modulation of β-catenin pathway core proteins, supposedly outside the domain of epithelial-mesenchymal transition, claims for further investigation.

TRIAL REGISTRATION

EU Clinical Trial Register, EudraCT number 2012-004956-12.

Alpelisib (ALP) + endocrine therapy (ET) in patients (pts) with PIK3CA-mutated hormone receptor-positive (HR+), human epidermal growth factor-2-negative (HER2-) advanced breast cancer (ABC): First interim BYLieve study results

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Background: In the phase 3 SOLAR-1 study, ALP + fulvestrant (FUL) improved PFS in pts with HR+, HER2– ABC with a PIK3CA mutation overall and in the small group of pts with prior cyclin-dependent kinase 4/6 inhibitor (CDKi) use. We report interim data from the BYLieve study in pts with PIK3CA-mutated ABC and prior CDKi exposure. Methods: BYLieve is an ongoing, phase 2, open-label, non-comparative study of ALP 300 mg QD + ET in men and women with PIK3CA-mutated HR+, HER2– ABC whose disease progressed on/after CDKi + ET. Pts are permitted ≤2 prior anticancer therapies and ≤1 prior chemotherapy regimen for ABC. Pts with prior CDKi and AI ( FUL cohort) receive ALP and FUL 500 mg Q28d + C1d15 IM. Pts with prior CDKi and FUL ( LET cohort) receive ALP and letrozole (LET) 2.5 mg PO QD. In this preplanned interim analysis, conducted after ≥20 pts in FUL had ≥6 mo of follow-up, descriptive data are reported for preliminary safety and efficacy in the FUL and LET cohorts. Results: At data cutoff, 64 and 36 pts were enrolled in the FUL and LET cohorts, respectively; 39 pts ( FUL, n = 21; LET, n = 18) have safety and efficacy data with ≥6 mo follow-up and are reported here. Data on 100 pts enrolled at the time of data cutoff will be presented. In the 39 pts with ≥6 mo follow-up, median ALP duration was 5.3 and 5.5 mo in FUL and LET, respectively; median duration of FUL and LET was 5.6 mo. Median relative ALP dose intensity was 93% ( FUL) and 87% ( LET). Most common grade ≥3 adverse events were hyperglycemia (38.1% ( FUL) and 27.8% ( LET)) and rash (4.8% ( FUL) and 27.8% ( LET)). Only 2 pts (5%; 1 pt per cohort) discontinued due to an AE. In pts with centrally confirmed PIK3CA mutation (n = 20 ( FUL); n = 17 ( LET)), ORR was 20% ( FUL) and 18% ( LET), CBR was 40% ( FUL) and 35% ( LET). Efficacy and safety data for the 100 enrolled pts will be presented at the meeting. Conclusions: Pending further readout of the ongoing BYLieve trial, safety and tolerability of ALP and hormonal therapy in pts with prior CDKi are consistent with those of SOLAR-1; discontinuation due to toxicity was rare. NCT03056755. Clinical trial information: NCT02437318.

Single Institution trial of anthracycline- and taxane-based chemotherapy for operable breast cancer: The ASTER study

The efficacy of anthracycline- and taxane-based chemotherapy for perioperative treatment of breast cancer (BC) has been established. No superiority of a cytotoxic regimen has been demonstrated, provided that administration of an anthracycline and a taxane is warranted. The ASTER study was designed to investigate the safety of 6 months of perioperative chemotherapy with Doxorubicin and Paclitaxel, followed by Cyclophosphamide, Methotrexate, and 5-Fluorouracil. ASTER enrolled patients with cT2-3 N0-1 or pT1-2 N1-3 BC, from November 2008 to August 2011. Treatment consisted of Doxorubicin 60 mg/sm, Paclitaxel 200 mg/sm q21 (AT) for three cycles followed by Cyclophosphamide 600 mg/sm, Methotrexate 40 mg/sm, 5-Fluorouracil 600 mg/sm d1,8 q28 (CMF) for three cycles, in either neo-adjuvant or adjuvant setting. All HER-positive patients received targeted therapy with Trastuzumab for 1 year. Disease-free and overall survival (DFS and OS, respectively) were estimated according to Kaplan-Meier method. Three hundred and thirty patients were enrolled, where 77.9% of cases were treated in an adjuvant setting; 65.5% received breast conservative surgery, 72.4% axillary dissection. 75.5% of cases presented estrogen receptor positivity, 66.7% progesterone receptor positivity; 18.5% of patients presented HER2-positive BC, 16.1% triple negative disease. Twenty-eight (8.5%) developed grade III-IV hematologic toxicity; nine patients (2.7%) developed grade III neurological toxicity. Loco-regional DFS was 99.6% at 1 year, 97.1% at 5 years, 95.9% at 7 years. Corresponding distant DFS was 98.4%, 90.2%, and 88.8%. One, 5, and 7-year OS was 99.6%, 94.9%, and 91.2%, respectively. Chemotherapy with ATx3→CMFx3 is confirmed safe and effective at 6.7 years follow-up. These results appear comparable to those reported in regulatory trials of most commonly prescribed anthracycline and taxane-based regimens.

Abstract P6-17-05: Independent validation of a combined biomarker based on the PAM50 HER2-enriched subtype and ERBB2 mRNA levels following HER2 blockade without chemotherapy in the PerELISA phase II trial

Background: A combined biomarker based on HER2-enriched subtype (HER2-E) and ERBB2 mRNA predicts response and survival in HER2+ breast cancer following trastuzumab +/- lapatinib in the absence of chemotherapy (Prat et al. ASCO 2018). Here, we tested the ability of the combined biomarker to predict pathological complete response (pCR) following neoadjuvant trastuzumab, pertuzumab and endocrine therapy.

Methods: RNA from 40 baseline tumor samples from the phase II PerELISA trial were evaluated. PerELISA evaluated the efficacy of a de-escalated, chemotherapy-free neoadjuvant regimen based on dual HER2 blockade with trastuzumab and pertuzumab in combination with letrozole in HER2+/hormone receptor-positive breast cancer selected on the basis of Ki67 response after short course letrozole-alone (Guarneri ASCO 2018). Ki67 response was defined by protocol as relative Ki67 reduction ≥20% from baseline at day 14. Gene-expression was measured using the nCounter platform. Intrinsic subtypes and ERBB2 levels were determined by the PAM50 gene expression predictor. A pre-specified ERBB2 cutoff was determined to define ERBB2-high. Univariate and multivariable logistic regression analyses were performed.

Results: The proportion of HER2-E disease within the ERBB2-high and ERBB2-low groups was 46.2% (6/13) and 18.5% (5/27), respectively. The discordance rate at the individual level was 30% (12/40). A total of 6 (15%) and 34 (85%) samples were HER2-E/ERBB2-high and others, respectively. The magnitude of Ki67 reduction of the HER2-E/ERBB2-high and others groups was 64.8% and 63.2%, respectively (p=0.88). The pCR rate of HER2-E/ERBB2-high was 66.7%. The pCR rate of the others group was 14.7%. The univariate odds ratio between HER2-E/ERBB2-high tumors and the others groups was 11.60 (95% CI 1.66-81.10; p=0.014). No other clinical-pathological variable was significantly associated with pCR.

Conclusion: The combined HER2-E/ERBB2-high biomarker can identify patients who might be good candidates to receive dual HER2 blockade alone without chemotherapy.

Citation Format: Prat A, Griguolo G, Dieci MV, Bisagni G, Frassoldati A, Bianchi GV, Pascual T, Pare L, Galvan P, Urso L, Conte P, Guarneri V. Independent validation of a combined biomarker based on the PAM50 HER2-enriched subtype and ERBB2 mRNA levels following HER2 blockade without chemotherapy in the PerELISA phase II trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-05.

Abstract P1-10-07: Efficacy and safety results from a randomized, phase II study of CC-486 in combination with fulvestrant in postmenopausal women with estrogen receptor–positive (ER+), human epidermal growth factor receptor 2–negative (HER2−) metastatic breast cancer (MBC)

Background: Most patients diagnosed with breast cancer have ER+ tumors. Treatment of ER+ MBC typically involves endocrine therapy, including aromatase inhibitors and selective ER modulators such as tamoxifen; however, many patients develop resistance. Fulvestrant, an ER antagonist, is a commonly prescribed second- or third-line therapy for postmenopausal patients who have progressed on endocrine therapy; although, most patients will eventually develop resistance to this drug as well. It was hypothesized that CC-486, an oral formulation of azacitidine, may resensitize patients to endocrine therapy and possibly delay resistance to fulvestrant through the epigenetic regulation of certain genes.

Methods: 97 postmenopausal female patients aged ≥ 18 years with ER+, HER2− MBC refractory to an aromatase inhibitor were randomized 1:1 to receive CC-486 300 mg on days 1 through 21 and fulvestrant 500 mg on days 1 and 15 of cycle 1 and day 1 of subsequent 28-day cycles or the same fulvestrant regimen alone. The primary endpoint was progression-free survival (PFS) based on investigator's assessment using RECIST version 1.1 and summarized by the Kaplan-Meier method. A Cox proportional hazards model was used to estimate the hazard ratio (HR; including a 2-sided 95% CI), and a log-rank test was used to calculate P values for comparisons between treatment arms. Key secondary endpoints included objective response rate (ORR), overall survival (OS), and safety.

Results: 48 patients were included in the CC-486 + fulvestrant arm and 49 in the fulvestrant-alone arm. Median age was 63 years. Baseline characteristics were generally balanced between treatment groups, with some exceptions. The CC-486 + fulvestrant treatment cohort had fewer patients aged ≥ 65 years (40% vs 49%), with an ECOG PS of 1 (25% vs 57%), or with liver metastases (29% vs 43%) than did the fulvestrant-alone cohort. At the time of this analysis, 36 patients (75%) in the CC-486 + fulvestrant arm and 40 patients (82%) in the fulvestrant-alone arm had discontinued treatment, mostly due to progressive disease (81% and 90%, respectively). Median PFS was 5.5 months in both treatment groups (HR 0.87; 95% CI, 0.54 - 1.42; P = 0.599). ORR was 8.3% vs 2.0% in patients receiving CC-486 + fulvestrant vs fulvestrant alone, respectively. Median OS has not been reached. In patients who received CC-486 + fulvestrant, the most common any-grade nonhematologic treatment-emergent adverse events (TEAEs) were nausea (78%), vomiting (78%), diarrhea (44%), and constipation (41%), and the most frequent any-grade hematologic TEAE was neutropenia (26%). Of patients who discontinued due to AEs, most patients receiving CC-486 + fulvestrant treatment discontinued due to gastrointestinal (GI) TEAEs.

Conclusion: The addition of CC-486 to fulvestrant did not improve PFS in patients with ER+, HER2− MBC compared with fulvestrant alone, and GI TEAEs were reported in a majority of patients. These results do not support further evaluation of this combination in this setting.

Citation Format: Campone M, Sachdev J, Bianchi GV, Beck JT, Martínez-Jáñez N, Cortes J, Schmidt M, Zamagni C, Chen P, Miller J, Fandi A, Gianni L. Efficacy and safety results from a randomized, phase II study of CC-486 in combination with fulvestrant in postmenopausal women with estrogen receptor–positive (ER+), human epidermal growth factor receptor 2–negative (HER2−) metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-10-07.

Abstract P2-02-19: Circulating tumor DNA detection anticipates disease recurrence in early stage breast cancer: A pilot study generating an observational confirmatory trial

Sensitive tumor biomarkers able to monitor disease progression would contribute to post-surgical treatment decision making in early breast cancer. We investigated the feasibility of using circulating tumor DNA (ctDNA) to early detect new disease manifestations in serial plasma samples collected during post-surgery follow-up from patients operated for stage I breast cancer from 1992 to 1993 at Istituto Nazionale Tumori in Milan. Forty patients that underwent radical or conservative surgery for T1/T2-N0-M0 breast cancer and that were followed for at least 15 years were included in a pilot study for the retrospective analysis of ctDNA on at least 3 plasma samples obtained during follow-up. To assess the feasibility of ctDNA analysis in archival plasma samples collected in heparin and stored from 10 to 25 years, preliminary experiments demonstrated that ctDNA was not affected by: 1) heparinase I digestion of extracted DNA and 2) DNA pre-amplification step to overcome limitations due to small plasma aliquots. Mutational analysis of breast cancer tissues was performed by Ion Torrent-targeted next generation sequencing and the identified Single Nucleotide Variations (SNV) were first validated and then tracked in plasma samples by using ad hoc digital polymerase chain reaction assays. One or more SNVs were identified in tumor tissue specimens and validated in 27/40 cases. Among those 27 breast cancers, 6 cases relapsed locally, 4 in distant sites, and 17 remained disease-free for the entire follow-up. ctDNA was undetectable during the post-surgical follow-up in 16/17 disease-free women up to 160 months of surgery, while it was detectable in 9/10 patients developing unfavorable events and anticipated the clinical diagnosis of relapse in 7/10 patients with a median lead time of 20 months. Our results are the first to associate mutation tracking to local recurrence and indicate that in patients with early breast cancer ctDNA monitoring during post-operative follow-up can anticipate the diagnosis of new disease manifestations, thus potentially allowing prompt treatments. These findings establish the rational to plan prospective studies to evaluate in the early breast cancer context the potential of ctDNA as a non-invasive and sensitive biomarker for monitoring tumor progression. Based on these results, we activated in 2016 a prospective observational study to confirm the predictive value of ctDNA on local and distant relapse in patients with early and localized triple negative breast cancer. As for May 2017, 145 patients with triple negative tumors were potentially enrolled for a ctDNA-based post-surgical follow-up: 111 cases at first diagnosis and 34 cases at surgery after neo-adjuvant treatment. One hundred-ten women accepted to participate in the study and signed a specific informed consent, whereas 22 patients refused to participate and 13 were lost to follow-up. For 94 patients (66 at initial diagnosis and 28 after neoadjuvant chemotherapy) plasma samples have been already longitudinally collected and DNA sequencing is currently in progress.

Citation Format: Daidone MG, Di Cosimo S, Veneroni S, Cascone F, De Cecco L, Dugo M, Folli S, Bianchi GV, Tamborini E, Busico A, Appierto V. Circulating tumor DNA detection anticipates disease recurrence in early stage breast cancer: A pilot study generating an observational confirmatory trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-19.

Trastuzumab and Hypofractionated Whole Breast Radiotherapy: A Victorious Combination?

INTRODUCTION

The purpose of this study was to examine the impact of trastuzumab on acute skin and cardiac toxicity in patients with breast cancer treated with chemotherapy with or without trastuzumab and adjuvant whole breast hypofractionated radiotherapy (hypo-RT).

MATERIALS AND METHODS

The study was conducted on 727 patients treated from April 2009 to October 2016. Patients received 42.4 Gy in 16 daily fractions (2.65 Gy per fraction). A boost was only administered in cases with grade (G) 3 primary tumor and close or positive margins. Acute and late toxicity was assessed prospectively during and after hypo-RT, based on the Radiation Therapy Oncology Group scale. Multivariable logistic regression models were used to examine the onset of acute skin toxicity (≥ G2) in the whole study population, and the impact of trastuzumab on the onset of acute skin (≥ G2) or cardiac toxicity in the subgroup of 176 patients given chemotherapy.

RESULTS

A total of 176 patients received chemotherapy with anthracycline and taxane, and 51 (29%) of them were also treated with trastuzumab. Acute G1, G2, and G3 skin toxicity occurred, respectively, in 56.8%, 27.3%, and 1.1% of the patients given chemotherapy alone, and in 64.7%, 19.6%, and 0% of those given trastuzumab as well. Among the patients given chemotherapy, left ventricular ejection fraction (LVEF) toxicity developed with a severity of G1 (LVEF < 60%-50%) in 12 (6.8%) patients, G2 (LVEF < 50%-40%) in 2 (1.1%) patients, and G3 (LVEF < 40%) in 1 (0.6%) patient. Among the patients also given trastuzumab, 7 (13.7%) patients had G1 LVEF toxicity, and 1 (2%) patient had G2 LVEF toxicity. We found that patients given trastuzumab were at higher risk of cardiac toxicity ≥ G1 (odds ratio, 4.3; P = .01), and at lower risk of acute skin toxicity ≥ G2 (odds ratio, 0.4; P = .03) than patients given chemotherapy alone.

CONCLUSIONS

This analysis showed that trastuzumab with adjuvant hypo-RT for patients with breast cancer was generally well-tolerated in routine clinical practice. A longer follow-up will be necessary to assess late cardiac toxicity.

Efficacy and safety of Everolimus and Exemestane in hormone-receptor positive (HR+) human-epidermal-growth-factor negative (HER2-) advanced breast cancer patients: New insights beyond clinical trials. The EVA study

BACKGROUND

The BOLERO-2 trial reported efficacy and safety of Everolimus (EVE) and Exemestane (EXE) combination in HR+ advanced breast cancer (ABC) patients. The BALLET trial further evaluated the safety of EVE-EXE in HR+ ABC patients, without reporting efficacy data. Aim of the EVA real-life study was to collect data of efficacy and safety of EVE-EXE combination in the clinical setting, as well as exploring efficacy according to EVE Dose-Intensity (DI) and to previous treatment with Fulvestrant.

PATIENTS AND METHODS

This study aimed to describe the outcome of ABC pts treated with EVE-EXE combination in terms of median duration of EVE treatment and ORR in a real-life setting.

RESULTS

From July 2013 to December 2015, the EVA study enrolled 404 pts. Median age was 61 years (33-83). Main metastatic sites were: bone (69.1%), soft tissue (34.7%) and viscera (33.2%). Median number of previous treatments was 2 (1-7). 43.3% of the pts had received Fulvestrant. Median exposure to EVE was 31.0 weeks (15.4-58.3) in the whole population. No difference was observed in terms of EVE exposure duration according to DI (p for trend = 0.27) or type of previous treatments (p = 0.33). ORR and Disease Control Rate (DCR) were observed in 31.6% and 60.7% of the patients, respectively, with the lowest ORRs confined in CHT pre-treated patients or in those who received the lowest DI of EVE. Grade 3-4 adverse events (AEs) were reported in 37.9% of the patients. Main AEs were: stomatitis (11.2%), non-infectious pneumonitis - NIP (3.8%), anaemia (3.8%) and fatigue (3.2%).

CONCLUSIONS

The EVA study provided new insights in the use of EVE-EVE combination in HR+ ABC pts many years after the publication of the pivotal trial. The combination is safe and the best response could be obtained in patients receiving the full dose of EVE and/or after hormone-therapy as Fulvestrant in ABC.

Safety and antitumor activity of weekly carboplatin plus paclitaxel in metastatic breast cancer: A ten years, single-institution, retrospective analysis

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Background: Safety and activity of weekly carboplatin plus paclitaxel in patients (pts) with metastatic breast cancer (mBC) are poorly known. Nevertheless, taxane-based chemotherapy (ChT) is the milestone in mBC treatment. In this retrospective analysis, we report the safety and clinical activity of this combination in a consecutive series of pts treated at IRCCS Fondazione Istituto Nazionale dei Tumori in Milan in the last decade. Methods: We collecteddata on mBC patients treated between January 2007 and December 2016 with carboplatin AUC 2 plus paclitaxel 80 mg/m2on days 1 and 8, every three weeks. Selection criteria were: ECOG 0-1; evaluable and/or measurable mBC; known estrogen and progesterone receptors (ER/PgR) status and HER2 expression levels. 274 pts fulfilled the selection criteria, and 265 pts were evaluable for response and survival. Response was assessed according to RECIST criteria. Results: The median number of administered cycles was 6 (range 1-17). 66.4% and 88.3% of pts had received taxanes or antracyclines, respectively, as an adjuvant treatment or in the metastatic setting. 97% of HER2+ pts received trastuzumab concomitant with ChT. Among patients with ER/PgR-positive tumors, 42.8% received different endocrine treatments as maintenance therapy after achieving the best response with ChT or due inacceptable toxicity. Hematological and gastrointestinal toxicities were the most frequent adverse events (AEs), and were severe in 19% and 1.2% of pts, respectively. In particular, G3-G4 neutropenia and febrile neutropenia occurred in 16.8 % and 1.9 % of pts, respectively. 10.2% of pts discontinued the treatment because of toxicity. The objective response rate was 44.8% in the overall population, with median progression free survival (mPFS) of 8.6 months and median overall survival (mOS) of 23.7 months. Conclusions: Weekly carboplatin plus paclitaxel is a well-tolerated and active regimen across all different molecular subgroups of mBC. [Table: see text]

Abstract P1-09-04: Proliferation and p21 refine risk of relapse in residual disease after HER2-directed therapies

Background: Patients (pts) with residual disease (RD) after neoadjuvant therapy are at higher risk of relapse. We investigated whether biomarkers assessed at surgery in patients pts with RD in the NeoSphere study were informative for risk of distant event free survival (DEFS)

Methods: In NeoSphere 417 HER2+ pts were randomized to neoadjuvant TD, TPD, TP or PD (T=trastuzumab, P=pertuzumab, D=docetaxel), and received FAC/FEC and trastuzumab after surgery. 296 pts had RD. Affymetrix derived gene expression profiles (GEPs) were available at surgery for 201 pts (67.9%). 176 pts (60.1%) had paired samples before and after treatment with available GEPs. We investigated the prognostic value of proliferation evaluated by Mitosis Kinase Score (MKS) (Bianchini G Cancer Res 2010), and performed a gene discovery for association between gene expression at surgery and DEFS.

Results: MKS as continuous marker was associated with significantly higher risk of relapse when assessed at surgery (HR 1.80 [1.23-2.65]; p=0.002), but not before treatment (HR 1.50 [0.80-2.78]; p=0.20). In paired samples, there was an average decrease (p=9.2E-11) of MKS after treatment, which was prominent in ER+ and chemotherapy-containing arms. In ER- and TP arm there were cases of increase and of decrease of MKS. In ER+ the 5 years DEFS was 94.3% in the Low/Int MKS tertiles group (pooled) vs 70.5% in the High MKS tertile group (HR 5.41 [1.87-15.6]; p=0.002). In ER-, the 5 years DEFS was 85.0% in the Low/Int vs 64.1% in the High group (HR 2.89 [1.08-7.76]; p=0.035). Notably, MKS at surgery after the two monoclonal alone was also prognostic.

In the gene discovery approach only the expression of CDKN1A (p21)at surgery was associated with DEFS after correction for false discovery rate (FDR=0.01). Pre-treatment p21 was not associated with DEFS. Paired comparison showed significant upregulation of p21 in all patients, treatment arms and ER groups. The Int/High p21 tertiles group (pooled) had lower risk of recurrence than the low tertile in ER+ (HR 4.31 [1.60-11.6]; p=0.004) and in ER- (HR 5.81 [1.87-18.1]; p=0.002) groups. p21 in TP arm was also prognostic. MKS and p21 expression provided independent prognostic information and remained significant after correction for clinico-pathological variables (nodes and T stage) and tumor-infiltrating lymphocytes. Combining the two markers, there was a group at very low risk (Low/Int MKS and Int/High p21) and one at high risk (High MKS and Low p21). The other tertiles combinations had intermediate risk. In ER+, the 5 yrs DEFS was 94.9% in the low risk group and 52.9% in the high risk (p=1.9E-05). In ER-, the 5 yrs DEFS was 96.5% in the low and 45.5% in the high risk group (p=0.001).The markers' combination was also prognostic in the two monoclonal only arm.

Conclusions: Proliferation (MKS) and p21 expression are modulated by trastuzumab and/or pertuzumab regimens. Tumors with high MKS and low p21 in RD after neoadjuvant therapy defined a group at very high risk of relapse. Tumors with low/int proliferation and int/high p21 had low risk of recurrence similar to that of patients achieving pCR. Whether the pharmacodynamic modulation of p21 could be used as surrogate marker of long term benefit in patients with RD deserves additional investigation.

Citation Format: Bianchini G, Pienkowski T, Im Y-H, Bianchi GV, Tseng L-M, Liu M-C, Lluch A, de la Haba-Rodríguez J, Semiglazov V, Oh D-Y, Poirier B, Pedrini JL, Valagussa P, Gianni L. Proliferation and p21 refine risk of relapse in residual disease after HER2-directed therapies [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 P1-09-04.

Taxanes enhance trastuzumab-mediated ADCC on tumor cells through NKG2D-mediated NK cell recognition

Recent clinical data indicate a synergistic therapeutic effect between trastuzumab and taxanes in neoadjuvantly treated HER2-positive breast cancer (BC) patients. In HER2+ BC experimental models and patients, we investigated whether this synergy depends on the ability of drug-induced stress to improve NK cell effectiveness and thus trastuzumab-mediated ADCC. HER2+ BC cell lines BT474 and MDAMB361 treated with docetaxel showed up-modulation of NK activator ligands both in vitro and in vivo, accompanied by a 15-40% increase in in vitro trastuzumab-mediated ADCC; antibodies blocking the NKG2D receptor significantly reduced this enhancement. NKG2D receptor expression was increased by docetaxel treatment in circulating and splenic NK cells from mice xenografted with tumor cells, an increase related to expansion of the CD11b+Ly6G+ cell population. Accordingly, NK cells derived from HER2+ BC patients after treatment with taxane-containing therapy expressed higher levels of NKG2D receptor than before treatment. Moreover, plasma obtained from these patients recapitulated the modulation of NKG2D on healthy donors' NK cells, improving their trastuzumab-mediated activity in vitro. This enhancement occurred mainly using plasma from patients with low NKG2D basal expression. Our results indicate that taxanes increase tumor susceptibility to ADCC by acting on tumor and NK cells, and suggest that taxanes concomitantly administered with trastuzumab could maximize the antibody effect, especially in patients with low basal immune effector cytotoxic activity.

Abstract 3940: Baseline molecular markers and risk of distant relapse in the NeoSphere study

Background We investigated the association between gene-expression (GEP) based markers and distant event free survival (DEFS) in HER2+ breast cancer patients (pts) in the NeoSphere study.

Methods In NeoSphere HER2+ pts were randomized to neoadjuvant HD, PHD, PH or PD (H = trastuzumab, P = pertuzumab, D = docetaxel). Affymetrix-based GEPs were generated in 367/417 pts (88%). We evaluated the association with DEFS of 10 biomarkers in all patients with arms pooled and by each arm, and separately by ER status: six immune-related metagenes (CD8, IGG and MHC2, related to T cells, plasma cells and antigen presenting cells, respectively; MHC1, STAT1 and IF.I related to HLA cass I genes, and to genes modulated by interferons), ESR1 and an ER-related score (ERS), a proliferation marker (MKS) and ERBB2 expression. We re-assessed findings in GEPs derived from ER-/HER2+ pts of the NOAH trial treated with neoadjuvant chemotherapy (CT) or CT and trastuzumab (CTH).

Results Median follow-up was 5 years. Overall none of the markers was significant, but an interaction test for biomarkers and ER status was significant for MHC1, MHC2, STAT1, and marginally for MKS.

In ER+/HER2+ tumors, immune markers were not significant, but higher proliferation (MKS; HR 2.12 [1.07-4.19], p = 0.03) was linked to higher risk, with a similar trend for low ERS (p = 0.097). In ER-/HER2+ tumors higher MHC2 (HR 0.53 [0.36-0.79]; p = 0.002), MHC1 (HR 0.41 [0.22-0.77], p = 0.005) and STAT1 (HR 0.69 [0.49-0.97], p = 0.036) were linked to better DEFS. Outcome for high MHC1 tertile was excellent and similar in all treatment arms. Low/int MHC1 pts treated with PHD had a trend for better DEFS compared to other treatments (HR 0.41 (0.14-1.21), p = 0.11). In cases reaching pCR higher MHC1 (p = 0.009), MHC2 (p = 0.006), IGG (p = 0.027) and STAT1 (p = 0.008) were linked to better DEFS. For instance, the 5 yrs DEFS for high and low MHC1 tertiles was 100% and 74.6%, respectively.

Similarly, in ER-/HER2+ pts from NOAH, the 5-yrs DEFS in high, int and low MHC1 tertiles was 88.1%, 68.4% and 48.1%, respectively (p = 0.015). Prognosis was similar and good in patients with high MHC1 receiving CT or CTH (p = 0.674). Instead, in low/int MHC1 groups, CTH compared to CT significantly improved DEFS (HR 0.39 [0.16-0.93], p = 0.035). Also in NOAH, the 5 yrs DEFS of pCR cases was influenced by baseline MCH1 (100% and 76.2% with high and low/int MHC1, respectively).

Conclusions In this exploratory analysis of NeoSphere, different biological functions were linked to DEFS in ER+ (proliferation and ER-related genes) and ER- (immune related) cases. In particular outcome of ER-/HER2+ with high MHC1 was good. However, in this group the benefit from adding trastuzumab to CT or pertuzumab in the PHD regimen was relatively small. Instead, the benefit seemed significant and large in cases of low/int MHC1, who had higher relapse risk. Of note, baseline immune markers of ER-/HER2+ tumors were linked to different DEFS also for cases achieving pCR.

Citation Format: Giampaolo Bianchini, Tadeusz Pienkowski, Young-Hyuck Im, Giulia Valeria Bianchi, Ling-Ming Tseng, Mei-Ching Liu, Ana Lluch, Vladimir Semiglazov, Juan de la Haba-Rodríguez, Do-Youn Oh, Brigitte Poirier, Jose Luiz Pedrini, Pinuccia Valagussa, Luca Gianni. Baseline molecular markers and risk of distant relapse in the NeoSphere study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3940.

Pitfalls in oncology: a unique case of thoracic splenosis mimicking malignancy in a patient with resected breast cancer

Thoracic splenosis (TS) is a condition of autotransplantation of splenic tissue into the pleural cavity after thoraco-abdominal trauma, with diaphragmatic and spleen injury. It is usually asymptomatic and discovered as an incidental finding at imaging performed for other reasons. Its differential diagnosis regards different benign and malignant conditions and should be discerned avoiding invasive procedures. We report a case of thoracic mass associated with pleural nodules mimicking malignancy in a patient with resected breast cancer for whom a diagnosis of TS was made early by using non-invasive methods. Briefly, we review the literature data on TS, comment concisely the possible implications of using invasive procedures and describe the current non-invasive techniques available. Furthermore, we highlight the importance of an accurate medical history collection, the role of the multidisciplinary board and their impact on treatment decision making. Finally, we conclude that clinical information and imaging would be the discriminating factors to avoid unnecessary invasive procedures.

Predictive biomarkers in the treatment of HER2-positive breast cancer: an ongoing challenge

The transmembrane tyrosine kinase receptor HER2 is overexpressed in 20% of invasive breast cancers and is associated with more aggressive disease. Until the advent of targeted agents, HER2 was associated with worse outcome. Trastuzumab, a recombinant humanized anti-HER2 monoclonal antibody, combined with chemotherapy improves disease-free and overall survival in both primary and metastatic tumors and represents a foundation of care for patients with HER2-positive breast cancers. However, a sizeable number of patients do not respond to this reagent, indicating the need for a biomarker able to recognize resistant tumors. Here, we review various studies on mechanisms of action and resistance to trastuzumab that have proven relevant in understanding how tumor care can be tailored to all HER2-positive patients.

Metastatic breast cancer treated with lapatinib with a prolonged benefit: a case report and a review of therapeutic options available

A 53-year-old woman was treated, after trastuzumab progression of HER2-positive metastatic disease, with capecitabine plus lapatinib and subsequently with lapatinib alone. To date, she has had persistent remission of disease since 2009.

Lapatinib and letrozole as first-line therapy for metastatic breast cancer: case report of bone metastasis 18 years later

We describe a 63-year-old woman with a diagnosis of breast cancer who relapsed with multiple bone lesions 18 years later. The biological characteristics were estrogen receptor positive, progesterone receptor positive, and HER2-positive cancer. Lapatinib and letrozole was the treatment of choice as a manageable and active first-line therapy for this patient.

Abstract P3-12-13: First analysis of ASTER study AT for 3 cycles followed by CMF for 3 cycles as neo or adjuvant chemotherapy in early stage breast cancer. A single institution experience

Background: The ECTO study demonstrated the efficacy of concurrent doxorubicin and paclitaxel (AT) for 4 cycles followed by cyclophosphamyde/ methotrexate/fluorouracil (CMF) for 4 cycles in the neoadjuvant and adjuvant treatment of operable breast cancer (Gianni L. et al. JCO 2009). With the purpose of ameliorating the tolerability of the regimen, we designed the ASTER study to reduce both the duration and the total dose of treatment with AT followed by CMF. Herein we report on the first data of efficacy of the study and the toxicity.

Methods: A total of 345 patients with operable breast cancer were enrolled between September 2008 and November 2011. Median age was 50 years (range 23-74); 74.5% of patients presented with hormonal receptor positive (HR +) and 23,5% of patients with both hormonal receptor negative (HR-PgR-); 19% of patients presented HER2 over expression/amplification; half patients had Ki67 &gt;14%, almost of patients had pT1 (66%) or pT2 (30%) with 27,5% of pN0. Patients were treated with Adriamycin (60 mg/mq) + Paclitaxel (200 mg/mq) q21 for 3 cycles followed by CMF i.v. 1, 8q28 for 3 cycles (73 as neo-adjuvant and 272 as adjuvant regimen). After chemotherapy in patients with HER2+ trastuzumab was delivered for 1 yr and in patients with HR+ tumors hormonal treatment was recommended for 5 yr. Breast irradiation was mandatory after conserving surgery (64% of cases).

Results: At a median follow-up of 36 months, the relapse free survival (RFS) and overall survival (OS) were 92% and 96% respectively. As expected in patients HR+/HER2- RFS were 95% and OS 99%, in patients HER2+ RFS were 90% and OS 97% and in those HR-/HER2- 83% and 79% respectively.

In the neoadjuvant subset tnpCR, defined as the absence of invasive cells in the primary tumor and in nodes, was obtained in 10% of cases. A tnpCR was achieved in 27% of patients with triple negative cancer and only in 5% of HR positive cancer.

Peripheral neuropathy toxicity was reported in 37% of cases and was essentially mild to moderate. Only 8,7% of patients experienced neutropenia G 3, 4,3% GI toxicity G3 and 2,3% mucositis G3. No cardiotoxicity was documented even in the 65 patients who received postoperative trastuzumab to date.

Conclusions: This results of Aster study AT for 3 cycles followed by CMF for 3 cycles showed similar efficacy and very favorable toxicity compared whit our previous experience of eighth cycle of sequential and non cross resistant chemotherapy in early stage breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-12-13.

Lapatinib and Letrozole as First-Line Therapy for Metastatic Breast Cancer: Case Report of Bone Metastasis 18 Years Later

We describe a 63-year-old woman with a diagnosis of breast cancer who relapsed with multiple bone lesions 18 years later. The biological characteristics were estrogen receptor positive, progesterone receptor positive, and HER2-positive cancer. Lapatinib and letrozole was the treatment of choice as a manageable and active first-line therapy for this patient.

Hepatic trans-arterial chemoembolization (TACE) in metastatic breast cancer

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Background: Liver metastasis is one of the most frequent cause of death in breast cancer patients. Among loco-regional approaches available for solid tumor liver metastasis, TACE allows a prolonged intra-lesion exposure to chemotherapeutic agents. Initial studies have highlighted a benefit in terms of response rate (RR) and overall survival (OS) in breast cancer patients treated with TACE versus systemic chemotherapy. Methods: We have retrospectively evaluated 14 patients affected by breast cancer with liver metastasis. Patients had been selected for liver TACE according to the presence of liver metastasis as only site of disease, or in the event of further sites of metastasis that were stable or in response from the previous treatment. All the patients received one or more TACE with DC-Bead (Biocompatibles UK) 100-300 micron, loaded with a chemotherapeutic agent (doxorubicin, paclitaxel).The systemic therapy received by patients before TACE could be confirmed or changed according to disease response. Objective of the study was to evaluate the response rate to TACE and its correlation with the response to the very last treatment performed before it. As surrogate of efficacy, time to progression (TTP) and OS were analyzed. Results: Among the 14 treated patients (5 heavily pretreated, with more than three lines of chemotherapy) only one obtained a complete remission (RC). Four patients presented a partial remission (PR). Three of them were progressing from previous treatment and one had a PR. Stable disease (SD) after TACE was obtained in four cases: two of them had a progressive disease (PD) before TACE and two had a responsive disease. Five patients did not respond to TACE (one with PR from the previous line of therapy). Median TTP observed in responsive patients (CR + PR) was 4.5 times higher than non-responders (PD) (13.2 vs. 2.9 months). Patients with SD had a median TTP of 4.3 months. Median OS of responsive patients was 25.6 months vs. 17.5 and 19.2 months of patients with SD or PD respectively. Conclusions: In our experience, chemoembolization can represent a valid therapeutic option in breast cancer patients with liver metastasis, independently from the response to the previous systemic therapy, and may prolong survival.

Primary results from EMILIA, a phase III study of trastuzumab emtansine (T-DM1) versus capecitabine (X) and lapatinib (L) in HER2-positive locally advanced or metastatic breast cancer (MBC) previously treated with trastuzumab (T) and a taxane

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Background: T-DM1 is an antibody-drug conjugate comprising T, a stable linker, and the potent cytotoxic agent DM1; it incorporates the antitumor activities of T and the HER2-targeted delivery of DM1. Methods: EMILIA is a randomized study of T-DM1 vs XL, the only approved combination for T-refractory HER2+ MBC. Patients (pts) received T-DM1 (3.6 mg/kg IV q3w) or X (1,000 mg/m2PO bid, days 1–14 q3w) + L (1,250 mg PO daily) until progressive disease (PD) or unmanageable toxicity. Pts had confirmed HER2+ MBC (IHC3+ and/or FISH+), and prior therapy with T and a taxane. Primary end points were PFS by independent review, OS and safety. An interim OS analysis was planned at the time of the final PFS analysis. Results: 991 pts were enrolled; 978 received treatment. Median (med) durations of follow-up were 12.9 (T-DM1) and 12.4 (XL) months (mo). Baseline demographics, prior therapy and disease characteristics were balanced. There was a significant improvement in PFS favoring T-DM1 (med 9.6 vs 6.4 mo; HR=0.650 [95% CI, 0.549–0.771]; p < .0001). The med T-DM1 OS was not reached vs 23.3 mo (HR=0.621 [95% CI, 0.475–0.813]; p =.0005); the interim efficacy boundary was not crossed (HR= 0.617; p =.0003). T-DM1 was well tolerated with no unexpected safety signals. The most common Grade ≥3 adverse events (AEs) per treatment were for T-DM1: thrombocytopenia (12.9% vs 0.2%), increased AST (4.3% vs 0.8%), and increased ALT (2.9% vs 1.4%); for XL: diarrhea (20.7% vs 1.6%), palmar plantar erythrodysesthesia (16.4% vs 0) and vomiting (4.5% vs 0.8%). The table lists other end points. Conclusions: T-DM1 conferred a significant and clinically meaningful improvement in PFS compared with XL. Other end points support T-DM1 as an active and well-tolerated novel therapy for HER2+ advanced BC. [Table: see text]

P1-12-02: Patient-Reported Outcomes (PROs) from a Randomized Phase II Study (TDM4450g/BO21976) of Trastuzumab Emtansine (T-DM1) vs Trastuzumab Plus Docetaxel (HT) in Previously Untreated HER2−Positive Metastatic Breast Cancer (MBC)

Background: T-DM1 is an antibody-drug conjugate in development for HER2−positive cancer. As a single-agent, it has demonstrated promising efficacy and safety when administered after multiple lines of HER2−directed therapy. In the current study, we compared the safety and efficacy of T-DM1 to standard first-line treatment for HER2−positive MBC. This abstract highlights the PRO results in the context of efficacy and safety.

Methods: Patients with HER2−positive MBC and no prior MBC therapy were randomized 1:1 to T-DM1 3.6 mg/kg IV q3w or H 6 mg/kg IV (8 mg/kg in cycle 1) + T 75 or 100 mg/m2 IV q3w. Primary objectives were investigator-assessed progression free survival (PFS) and safety. Key secondary end points included objective response rate and the FACT-B Trial Outcome Index (TOI). Patients completed the FACT-B on day 1 of each treatment cycle. The FACT-B TOI, the primary PRO end point, comprises a subset of the FACT-B and provides a summary measure of physical and functional well being and breast cancer specific symptoms. Time to FACT-B TOI worsening (ie, ≥5 point decrease in TOI) was assessed with Kaplan-Meier methods and a Cox model. A repeated measures mixed effects (RMME) model was used to evaluate potential treatment effects on TOI across cycles. Preliminary PRO results based on a data cutoff of November 15, 2010, are included here; final data will be presented.

Results: A total of 137 patients were randomized (67 T-DM1, 70 HT). Baseline patient and disease characteristics were similar in each arm. Patients treated with T-DM1 had longer PFS (14.2 vs 9.2 months, HR=0.59, P= 0.035) with less toxicity (eg, 46.4% grade 3/4 adverse events with T-DM1 vs 89.4% with HT) than those treated with HT. ORR was similar in both arms (64.2% T-DM1, 58.0% HT). A total of 132 patients (65 T-DM1, 67 HT) were evaluable for PRO analyses with a high compliance rate. In a preliminary analysis, FACT-B TOI worsening was significantly delayed in the T-DM1 arm compared with the control arm (7.5 vs 3.5 months, HR=0.58, P=0.022). The RMME model showed a mean difference of 3.65 in FACT-B TOI scores (P=0.023), mainly driven by physical well being (PWB) scores (mean difference 2.28, P=0.002), favoring T-DM1. In addition, 5 of 7 PWB items showed significantly better mean scores in the T-DM1 arm: “lack of energy” (P=0.011), “trouble meeting needs of family” (P=0.025), “bothered by side effects” (P&lt;0.001), “feeling ill” (P=0.016) and “forced to spend time in bed” (P=0.015); the 2 remaining items, “nausea” and “pain,” showed numerically better mean scores with T-DM1.

Conclusions: Compared to HT, T-DM1 as first-line treatment of HER2−positive MBC conferred longer PFS and a more favorable toxicity profile. The PRO data suggest that T-DM1 is also associated with meaningfully improved tolerability relative to HT, contributing to an overall clinical benefit and better health-related quality of life. Thus, T-DM1 may improve the standard of care for patients with previously untreated HER2−positive MBC.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-02.