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.

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.

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.

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

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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.

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.

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.

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.

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.

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 >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.

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<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.