Abemaciclib plus a nonsteroidal aromatase inhibitor as initial therapy for HR+, HER2- advanced breast cancer: Final overall survival results of MONARCH 3

BACKGROUND

In MONARCH 2, the addition of abemaciclib to fulvestrant significantly improved both progression-free survival (PFS) and overall survival (OS) in patients with HR+, HER2- advanced breast cancer (ABC) with disease progression on prior endocrine therapy (ET). In MONARCH 3, the addition of abemaciclib to a nonsteroidal aromatase inhibitor (NSAI) as initial therapy for HR+, HER2- ABC significantly improved PFS. Here, we present the prespecified final OS results for MONARCH 3.

PATIENTS AND METHODS

MONARCH 3 is a randomized, double-blind, phase 3 study of abemaciclib plus NSAI (anastrozole or letrozole) versus placebo plus NSAI in postmenopausal women with HR+, HER2- ABC without prior systemic therapy in the advanced setting. The primary objective was investigator-assessed PFS; OS was a gated secondary endpoint, and chemotherapy-free survival (CFS) was an exploratory endpoint.

RESULTS

A total of 493 women were randomized 2:1 to receive abemaciclib plus NSAI (n = 328) or placebo plus NSAI (n = 165). After a median follow-up of 8.1 years, there were 198 OS events (60.4%) in the abemaciclib arm and 116 (70.3%) in the placebo arm (hazard ratio, 0.804; 95% confidence interval [CI], 0.637-1.015; P = 0.0664, non-significant). Median OS was 66.8 versus 53.7 months for abemaciclib versus placebo. In the subgroup with visceral disease (sVD), there were 113 OS events (65.3%) in the abemaciclib arm and 65 (72.2%) in the placebo arm (hazard ratio, 0.758; 95% CI, 0.558-1.030; P = 0.0757, non-significant). Median OS was 63.7 months versus 48.8 months for abemaciclib versus placebo. The previously demonstrated PFS benefit was sustained, and CFS numerically improved with the addition of abemaciclib. No new safety signals were observed.

CONCLUSION

Abemaciclib combined with an NSAI resulted in clinically meaningful improvement in median OS (ITT: 13.1 months; sVD: 14.9 months) in patients with HR+ HER2- ABC; however, statistical significance was not reached.

Trastuzumab deruxtecan in previously treated patients with HER2-positive metastatic breast cancer: updated survival results from a phase II trial (DESTINY-Breast01)

BACKGROUND

Primary analysis of the multicenter, open-label, single-arm, phase II DESTINY-Breast01 trial (median follow-up 11.1 months) demonstrated durable antitumor activity with trastuzumab deruxtecan (T-DXd) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab emtansine (T-DM1). We report updated cumulative survival outcomes with a median follow-up of 26.5 months (data cut-off 26 March 2021).

PATIENTS AND METHODS

Patients with HER2-positive mBC resistant or refractory to T-DM1 received T-DXd 5.4 mg/kg intravenously every 3 weeks until disease progression, unacceptable adverse events, or withdrawal of consent. The primary endpoint was confirmed objective response rate (ORR) by independent central review (ICR). Secondary endpoints included overall survival (OS), duration of response (DoR), progression-free survival (PFS), and safety.

RESULTS

The ORR by ICR was 62.0% [95% confidence interval (CI) 54.5% to 69.0%] in patients who received T-DXd 5.4 mg/kg every 3 weeks (n = 184). Median OS was 29.1 months (95% CI 24.6-36.1 months). Median PFS and DoR were 19.4 months (95% CI 14.1-25.0 months) and 18.2 months (95% CI 15.0 months-not evaluable), respectively. Drug-related treatment-emergent adverse events (TEAEs) were observed in 183 patients (99.5%), and 99 patients (53.8%) had one or more grade ≥3 TEAEs. Adjudicated drug-related interstitial lung disease/pneumonitis occurred in 15.8% of patients (n = 29), of which 2.7% (n = 5) were grade 5.

CONCLUSIONS

These updated results provide further evidence of sustained antitumor activity of T-DXd with a consistent safety profile in heavily pretreated patients with HER2-positive mBC.

Validation of Electrocardiogram Based Photoplethysmogram Generated Using U-Net Based Generative Adversarial Networks

Photoplethysmogram (PPG) performs an important role in alarming atrial fibrillation (AF). While the importance of PPG is emphasized, there is insufficient amount of openly available atrial fibrillation PPG data. We propose a U-net-based generative adversarial network (GAN) which synthesize PPG from paired electrocardiogram (ECG). To measure the performance of the proposed GAN, we compared the generated PPG to reference PPG in terms of morphology similarity and also examined its influence on AF detection classifier performance. First, morphology was compared using two different metrics against the reference signal: percent root mean square difference (PRD) and Pearson correlation coefficient. The mean PRD and Pearson correlation coefficient were 27% and 0.94, respectively. Heart rate variability (HRV) of the reference AF ECG and the generated PPG were compared as well. The p-value of the paired t-test was 0.248, indicating that no significant difference was observed between the two HRV values. Second, to validate the generated AF PPG dataset, four different datasets were prepared combining the generated PPG and real AF PPG. Each dataset was used to optimize a classification model while maintaining the same architecture. A test dataset was prepared to test the performance of each optimized model. Subsequently, these datasets were used to test the hypothesis whether the generated data benefits the training of an AF classifier. Comparing the performance metrics of each optimized model, the training dataset consisting of generated and real AF PPG showed a test accuracy result of 0.962, which was close to that of the dataset consisting only of real AF PPG data at 0.961. Furthermore, both models yielded the same F1 score of 0.969. Lastly, using only the generated AF PPG dataset resulted in test accuracy of 0.945, indicating that the trained model was capable of generating valuable AF PPG. Therefore, it can be concluded that the generated AF PPG can be used to augment insufficient data. To summarize, this study proposes a GAN-based method to generate atrial fibrillation PPG that can be used for training atrial fibrillation PPG classification models.

Retrospective study to estimate the prevalence and describe the clinicopathological characteristics, treatments received, and outcomes of HER2-low breast cancer

BACKGROUND

Approximately 80% of all breast cancers (BCs) are currently categorized as human epidermal growth factor receptor 2 (HER2)-negative [immunohistochemistry (IHC) 0, 1+, or 2+/in situ hybridization (ISH) negative]; approximately 60% of BCs traditionally categorized as HER2-negative express low levels of HER2. HER2-low (IHC 1+ or IHC 2+/ISH-) status became clinically actionable with approval of trastuzumab deruxtecan to treat unresectable/metastatic HER2-low BC. Greater understanding of patients with HER2-low disease is urgently needed.

PATIENTS AND METHODS

This global, multicenter, retrospective study (NCT04807595) included tissue samples from patients with confirmed HER2-negative unresectable/metastatic BC [any hormone receptor (HR) status] diagnosed from 2014 to 2017. Pathologists rescored HER2 IHC-stained slides as HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2 IHC 0 after training on low-end expression scoring using Ventana 4B5 and other assays at local laboratories (13 sites; 10 countries) blinded to historical scores. HER2-low prevalence and concordance between historical scores and rescores were assessed. Demographics, clinicopathological characteristics, treatments, and outcomes were examined.

RESULTS

In rescored samples from 789 patients with HER2-negative unresectable/metastatic BC, the overall HER2-low prevalence was 67.2% (HR positive, 71.1%; HR negative, 52.8%). Concordance was moderate between historical and rescored HER2 statuses (81.3%; κ = 0.583); positive agreement was numerically higher for HER2-low (87.5%) than HER2 IHC 0 (69.9%). More than 30% of historical IHC 0 cases were rescored as HER2-low overall (all assays) and using Ventana 4B5. There were no notable differences between HER2-low and HER2 IHC 0 in patient characteristics, treatments received, or clinical outcomes.

CONCLUSIONS

Approximately two-thirds of patients with historically HER2-negative unresectable/metastatic BC may benefit from HER2-low-directed treatments. Our data suggest that HER2 reassessment in patients with historical IHC 0 scores may be considered to help optimize selection of patients for treatment. Further, accurate identification of patients with HER2-low BC may be achieved with standardized pathologist training.

Novel Preosteoclast Populations in Obesity-Associated Periodontal Disease

Although there is a clear relationship between the degree of obesity and periodontal disease incidence, the mechanisms that underpin the links between these conditions are not completely understood. Understanding that myeloid-derived suppressor cells (MDSCs) are expanded during obesity and operate in a context-defined manner, we addressed the potential role of MDSCs to contribute toward obesity-associated periodontal disease. Flow cytometry revealed that in the spleen of mice fed a high-fat diet (HFD), expansion in monocytic MDSCs (M-MDSCs) significantly increased when compared with mice fed a low-fat diet (LFD). In the osteoclast differentiation assay, M-MDSCs isolated from the bone marrow of HFD-fed mice showed a larger number and area of osteoclasts with a greater number of nuclei. In the M-MDSCs of HFD-fed mice, several osteoclast-related genes were significantly elevated when compared with LFD-fed mice according to a focused transcriptomic platform. In experimental periodontitis, the number and percentage of M-MDSCs were greater, with a significantly larger increase in HFD-fed mice versus LFD-fed mice. In the spleen, the percentage of M-MDSCs was significantly higher in HFD-fed periodontitis-induced (PI) mice than in LFD-PI mice. Alveolar bone volume fraction was significantly reduced in experimental periodontitis and was further decreased in HFD-PI mice as compared with LFD-PI mice. The inflammation score was significantly higher in HFD-PI mice versus LFD-PI mice, with a concomitant increase in TRAP staining for osteoclast number and area in HFD-PI mice over LFD-PI mice. These data support the concept that M-MDSC expansion during obesity to become osteoclasts during periodontitis is related to increased alveolar bone destruction, providing a more detailed mechanistic appreciation of the interconnection between obesity and periodontitis.

Long-term efficacy and safety of addition of carboplatin with or without veliparib to standard neoadjuvant chemotherapy in triple-negative breast cancer: 4-year follow-up data from BrighTNess, a randomized phase 3 trial

BACKGROUND

Primary analyses of the phase 3 BrighTNess trial showed addition of carboplatin with/without veliparib to neoadjuvant chemotherapy significantly improved pathological complete response (pCR) rates with manageable acute toxicity in patients with triple-negative breast cancer (TNBC). Here, we report 4.5-year follow-up data from the trial.

DESIGN

Women with untreated stage II-III TNBC were randomized (2:1:1) to paclitaxel (weekly for 12 doses) plus either: (a) carboplatin (every 3 weeks for four cycles) plus veliparib (twice daily); (b) carboplatin plus veliparib placebo; or (c) carboplatin placebo plus veliparib placebo. All patients then received doxorubicin and cyclophosphamide (AC) every 2‒3 weeks for four cycles. The primary endpoint was pCR. Secondary endpoints included event-free survival (EFS), overall survival (OS), and safety. Since the co-primary endpoint of increased pCR with carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel was not met, secondary analyses are descriptive.

RESULTS

Of 634 patients, 316 were randomized to carboplatin plus veliparib with paclitaxel, 160 to carboplatin with paclitaxel, and 158 to paclitaxel. With median follow-up of 4.5 years, the hazard ratio [HR] for EFS for carboplatin plus veliparib with paclitaxel versus paclitaxel was 0.63 (95% confidence interval [CI] 0.43‒0.92, P=0.02), but 1.12 (95% CI 0.72‒1.72, P=0.62) for carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel. In post hoc analysis, HR for EFS was 0.57 (95% CI 0.36‒0.91, P=0.02) for carboplatin with paclitaxel versus paclitaxel. OS did not differ significantly between treatment arms, nor did rates of myelodysplastic syndromes, acute myeloid leukemia, or other secondary malignancies.

CONCLUSION

Improvement in pCR with addition of carboplatin was associated with long-term EFS benefit with a manageable safety profile, and without increasing the risk of second malignancies, while adding veliparib did not impact EFS. These findings support the addition of carboplatin to weekly paclitaxel followed by AC neoadjuvant chemotherapy for early stage TNBC.

Adjuvant abemaciclib combined with endocrine therapy for high-risk early breast cancer: updated efficacy and Ki-67 analysis from the monarchE study

BACKGROUND

Adjuvant abemaciclib combined with endocrine therapy (ET) previously demonstrated clinically meaningful improvement in invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS) in hormone receptor-positive, human epidermal growth factor receptor 2-negative, node-positive, high-risk early breast cancer at the second interim analysis, however follow-up was limited. Here, we present results of the prespecified primary outcome analysis and an additional follow-up analysis.

PATIENTS AND METHODS

This global, phase III, open-label trial randomized (1 : 1) 5637 patients to adjuvant ET for ≥5 years ± abemaciclib for 2 years. Cohort 1 enrolled patients with ≥4 positive axillary lymph nodes (ALNs), or 1-3 positive ALNs and either grade 3 disease or tumor ≥5 cm. Cohort 2 enrolled patients with 1-3 positive ALNs and centrally determined high Ki-67 index (≥20%). The primary endpoint was IDFS in the intent-to-treat population (cohorts 1 and 2). Secondary endpoints were IDFS in patients with high Ki-67, DRFS, overall survival, and safety.

RESULTS

At the primary outcome analysis, with 19 months median follow-up time, abemaciclib + ET resulted in a 29% reduction in the risk of developing an IDFS event [hazard ratio (HR) = 0.71, 95% confidence interval (CI) 0.58-0.87; nominal P = 0.0009]. At the additional follow-up analysis, with 27 months median follow-up and 90% of patients off treatment, IDFS (HR = 0.70, 95% CI 0.59-0.82; nominal P < 0.0001) and DRFS (HR = 0.69, 95% CI 0.57-0.83; nominal P < 0.0001) benefit was maintained. The absolute improvements in 3-year IDFS and DRFS rates were 5.4% and 4.2%, respectively. Whereas Ki-67 index was prognostic, abemaciclib benefit was consistent regardless of Ki-67 index. Safety data were consistent with the known abemaciclib risk profile.

CONCLUSION

Abemaciclib + ET significantly improved IDFS in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative, node-positive, high-risk early breast cancer, with an acceptable safety profile. Ki-67 index was prognostic, but abemaciclib benefit was observed regardless of Ki-67 index. Overall, the robust treatment benefit of abemaciclib extended beyond the 2-year treatment period.

Machine-Learning-Based Rehabilitation Prognosis Prediction in Patients with Ischemic Stroke Using Brainstem Auditory Evoked Potential

To evaluate the feasibility of brainstem auditory evoked potential (BAEP) for rehabilitation prognosis prediction in patients with ischemic stroke, 181 patients were tested using the Korean version of the modified Barthel index (K-MBI) at admission (basal K-MBI) and discharge (follow-up K-MBI). The BAEP measurements were performed within two weeks of admission on average. The criterion between favorable and unfavorable outcomes was defined as a K-MBI score of 75 at discharge, which was the boundary between moderate and mild dependence in daily living activities. The changes in the K-MBI scores (discharge-admission) were analyzed by nonlinear regression models, including the artificial neural network (ANN) and support vector machine (SVM), with the basal K-MBI score, age, and interpeak latencies (IPLs) of the BAEP (waves I, I-III, and III-V). When including the BAEP features, the correlations of the ANN and SVM regression models increased to 0.70 and 0.64, respectively. In the outcome prediction, the ANN model with the basal K-MBI score, age, and BAEP IPLs exhibited a sensitivity of 92% and specificity of 90%. Our results suggest that the BAEP IPLs used with the basal K-MBI score and age can play an adjunctive role in the prediction of patient rehabilitation prognoses.

Estimation and Validation of Arterial Blood Pressure Using Photoplethysmogram Morphology Features in Conjunction With Pulse Arrival Time in Large Open Databases

Although various predictors and methods for BP estimation have been proposed, differences in study designs have led to difficulties in determining the optimal method. This study presents analyses of BP estimation methods using 2.4 million cardiac cycles of two commonly used non-invasive biosignals, electrocardiogram (ECG) and photoplethysmogram (PPG), from 1376 surgical patients. Feature selection methods were used to determine the best subset of predictors from a total of 42 including PAT, heart rate (HR), and various PPG morphology features, and BP estimation models constructed using linear regression (LR), random forest (RF), artificial neural network (ANN), and recurrent neural network (RNN) were evaluated. 28 features out of 42 were determined as suitable for BP estimation, in particular two PPG morphology features outperformed PAT, which has been conventionally seen as the best non-invasive indicator of BP. By modelling the low frequency component of BP using ANN and the high frequency component using RNN with the selected predictors, mean errors of 0.05 ± 6.92 mmHg for systolic BP, and -0.05 ± 3.99 mmHg for diastolic BP were achieved. External validation of the model using another biosignal database consisting of 334 intensive care unit patients led to similar results, satisfying three standards for accuracy of BP monitors. The results indicate that the proposed method can contribute to the realization of ubiquitous non-invasive continuous BP monitoring.

Reconstruction of 12-Lead Electrocardiogram from a Three-Lead Patch-Type Device Using a LSTM Network

Reconstructing a standard 12-lead electrocardiogram (ECG) from signals received from electrodes packed into a patch-type device is a challenging task in the field of medical instrumentation. All attempts to obtain a clinically valid 12-lead ECG using a patch-type device were not satisfactory. In this study, we designed the hardware for a three-lead patch-type ECG device and employed a long short-term memory (LSTM) network that can overcome the limitations of the linear regression algorithm used for ECG reconstruction. The LSTM network can overcome the issue of reduced horizontal components of the vector in the electric signal obtained from the patch-type device attached to the anterior chest. The reconstructed 12-lead ECG that uses the LSTM network was tested against a standard 12-lead ECG in 30 healthy subjects and ECGs of 30 patients with pathologic findings. The average correlation coefficient of the LSTM network was found to be 0.95. The ability of the reconstructed ECG to detect pathologic abnormalities was identical to that of the standard ECG. In conclusion, the reconstruction of a standard 12-lead ECG using a three-lead patch-type device is feasible, and such an ECG is an equivalent alternative to a standard 12-lead ECG.

Abstract OT3-02-02: PATHWAY: Asian, multicenter, phase 3 trial of tamoxifen with or without palbociclib ± goserelin in women with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer

BACKGROUND:

The incidence rates of breast cancer (BC) in Asian counties have been rising rapidly. The age-specific female BC incidence rates peak before menopause (around 40-50 years of age) in Asia, however treatment options for pre/perimenopausal patients are limited. Palbociclib (P) is an oral novel cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. The addition of P to endocrine therapy (ET) such as aromatase inhibitor or fulvestrant has been demonstrated improved progression-free survival (PFS) in phase 3 studies PALOMA-2 and PALOMA-3. This study is designed to evaluate efficacy and safety of P plus tamoxifen (TAM) in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic BC regardless of menopausal status. This study is conducted as a Clinical Research Collaboration by National Cancer Center Hospital with research funding from Pfizer.

TRIAL DESIGN:

PATHWAY/NCCH1607 is a double-blind, placebo-controlled, randomized, phase 3 study. Patients will be randomized 1:1 to receive either P (125 mg once daily, days1-21 of a 28-day cycle) or placebo in combination with TAM (20 mg once daily, continuously). Pre/perimenopausal women should receive concurrent ovarian function suppression with goserelin. Randomization will be stratified by prior ET for advanced/metastatic BC (1st line ET vs. 2nd line ET) and menopausal status (pre/perimenopausal vs. postmenopausal).

KEY ELIGIBILITY CRITERIA:

Eligible patients include women of any menopausal status with HR-positive, HER2-negative advanced or metastatic BC; candidates to receive TAM as 1st line or 2nd line ET for advanced/metastatic disease; ≥18 years of age; measurable or non-measurable disease (RECIST v.1.1); ECOG performance status 0-1; adequate organ function; have not received treatment with TAM (except for patients who have had more than 12 months from completion of adjuvant therapy with TAM); and have not received any CDK4/6 or phosphoinositide 3-kinase (PI3K) - mammalian target of rapamycin (mTOR) inhibitors.

SPECIFIC AIMS:

The primary endpoint is PFS as assessed by the investigator. Secondary endpoints include overall survival (OS), 1, 2, and 3-year survival probabilities, objective response (OR), duration of response, clinical benefit rate (CBR), pharmacokinetics, safety, and patient-reported outcomes.

STATISTICAL METHODS:

The sample size was determined to detect a 38% reduction in the hazard of disease progression or death in P plus TAM arm with a 1-sided significance level of 2.5% and power of 80%. A stratified log rank test will be used to compare PFS between the 2 treatment arms.

PRESENT ACCRUAL AND TARGET ACCRUAL:

Target accrual of 180 patients will be enrolled within 23 sites among Japan, Korea, Taiwan, and Singapore. As of June 2018, 46 patients have been enrolled.

CONTACT INFORMATION:

This trial is registered at ClinicalTrials.gov NCT03423199 and UMIN000030816. For more information, email NCCH1607_office@ml.res.ncc.go.jp

Citation Format: Noguchi E, Hata T, Nakamura K, Kuchiba A, Hayashi M, Hamada A, Yonemori K, Sohn J, Lu Y-S, Yap Y-S, Fujiwara Y, Tamura K. PATHWAY: Asian, multicenter, phase 3 trial of tamoxifen with or without palbociclib ± goserelin in women with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer [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 OT3-02-02.

Abstract P3-10-09: Relationship between tumor infiltrating lymphocytes (TILs) and response to pembrolizumab (Pembro)+chemotherapy (Chemo) as neoadjuvant treatment (NAT) for triple-negative breast cancer (TNBC): phase Ib KEYNOTE-173 trial

Background:Increasing quantities of stromal TILs (sTILs) are associated with higher pathologic complete response (pCR) rates with conventional chemo in early-stage TNBC. We evaluated the association between sTILs and PD-L1 expression with response to pembro+chemo as NAT for TNBC in the KEYNOTE-173 trial (NCT02622074).

Methods: sTILs were quantified using light microscopy of H&E-stained slides from pretreatment and on-treatment (during first 3 weeks of pembro monotherapy) tumor biopsies by a pathologist blind to response data. Pretreatment PD-L1 expression was assessed using the PD-L1 IHC 22C3 pharmDx assay and reported as combined positive score (CPS). Endpoints were pCR rate by ypT0 ypN0 and ypT0/Tis ypN0 and objective response rate (ORR; RECIST v1.1) after the first 4 cycles of NAT (taxane±carboplatin+pembro) by MRI. sTILs and PD-L1 CPS were evaluated as continuous variables. Association between sTILs and PD-L1 CPS with response was assessed using logistic regression and area under the reciever operating curve (AUROC) analyses, with a 1-sided alpha level of 0.10. Correlation between PD-L1 and sTILs was assessed by Spearman's rank correlation coefficient. Multivariate analysis included sTILs (pretreatment and on-treatment) and PD-L1 CPS. Likelihood ratio tests were used to evaluate the added value of factors in predicting pCR rate.

Results: Of 60 total pts, 34 had tumors evaluated for pretreatment sTILs, 52 for PD-L1 CPS, and 33 for both sTILs and CPS. On-treatment sTILs were evaluated in 31 pts. Overall pCR rates were 56.7% and 60% by ypT0 ypN0 and ypT0/Tis ypN0, respectively; ORR was 78.3%. In pts evaluated for sTILs and CPS (individually), pCR rates and ORR were comparable with overall pCR rates and ORR. There was a significant correlation between pretreatment sTILs and PD-L1 CPS (ρ=0.65, P&lt;0.001).Higher pretreatment sTILs were significantly associated with response: ypT0 ypN0 P= 0.011; ypT0/Tis ypN0 P=0.006; ORR P=0.061. On-treatment sTILs were also significantly associated with response: ypT0 ypN0 P=0.061; ypT0/Tis ypN0 P=0.041; ORR P=0.031. Pretreatment PD-L1 CPS was significantly associated with response: ypT0 ypN0 P=0.073; ypT0/is ypN0 P=0.030; and ORR P=0.021. AUROC of pretreatment sTIL association with pCR was numerically higher than with on-treatment sTILs and PD-L1 CPS (0.69 vs 0.61 vs 0.56 for ypT0ypN0 and 0.72 vs 0.67 vs 0.62 for ypT0/Tis ypN0). Responders had higher median pretreatment sTIL levels vs nonresponders: 45% [10, 75] vs 10% [5, 20] for pCR rate by ypT0 ypN0 and 52.5% [10, 73.8] vs 10% [5, 20] for pCR rate by ypT0/Tis ypN0; 25% [5, 70] vs 10% [6.3, 27.5] for ORR. In multivariate analysis, only pretreatment sTILs were significant for both pCR endpoints (ypT0 ypN0 P=0.031; ypT0/Tis ypN0 P=0.034). Likelihood ratio tests demonstrated that for both pCR endpoints, PD-L1 CPS (P=0.683/P=0.422) and on-treatment sTILs (P=0.984/P=0.568) did not add significantly more value to pretreatment sTILs when predicting pCR.

Conclusions:Higher quantities of pretreatment sTILs and PD-L1 CPS and on-treatment sTILs were significantly associated with higher pCR rates and ORR in primary TNBC treated with pembro and NAT.

Citation Format: Loi S, Schmid P, Cortés J, Park YH, Muñoz-Couselo E, Kim S-B, Sohn J, Im S-A, Holgado E, Foukakis T, Kuemmel S, Dent R, Wang A, Aktan G, Karantza V, Salgado R. Relationship between tumor infiltrating lymphocytes (TILs) and response to pembrolizumab (Pembro)+chemotherapy (Chemo) as neoadjuvant treatment (NAT) for triple-negative breast cancer (TNBC): phase Ib KEYNOTE-173 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 P3-10-09.

Abstract P6-18-06: Ribociclib treatment benefit in patients with advanced breast cancer with ≥1 dose reduction: Data from the MONALEESA-2, -3, and -7 trials

Background: In the MONALEESA (ML) trials, addition of ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor) to endocrine therapy (ET) prolonged progression-free survival (PFS) in patients (pts) with hormone receptor-positive (HR+), HER2-negative (HER2–) advanced breast cancer (ABC). RIB was generally well tolerated, with adverse events (AEs) managed effectively by dose modifications. Here we present efficacy data for RIB-based regimens of interest for the proposed indication (i.e. with a non-steroidal aromatase inhibitor [NSAI] or fulvestrant [FUL]) from ML-2, -3, and -7 in pts who received no prior ET for ABC and who had ≥1 RIB dose reduction, to explore the efficacy of RIB in pts who need to dose reduce.

Methods: Pts included in this analysis were: postmenopausal women with HR+, HER2– ABC and no prior ET for ABC who received RIB (600 mg; 3-weeks-on/1-week-off) with letrozole (2.5 mg/day; ML-2 [NCT01958021]), or FUL (500 mg per label; ML-3 [NCT02422615]); and premenopausal women with no prior ET and ≤1 line of chemotherapy for ABC who received RIB with an NSAI (anastrozole: 1 mg/day; letrozole: 2.5 mg/day; ML-7 [NCT02278120]) plus goserelin (3.6 mg every 28 days). Dose reductions for RIB (600 to 400 to 200 mg) were permitted. Primary endpoint was PFS. Secondary endpoints included overall response rate (ORR), clinical benefit rate (CBR), and safety.

Results: In ML-2, -3, and -7, ≥1 RIB dose reduction occurred (n/N) in 169/334 (51%), 92/238 (39%), and 91/246 (37%) pts assigned to RIB, respectively. AEs were the main reason for dose reduction, with all-grade neutropenia the most common AE leading to dose reduction (ML-2 69%, ML-3 80%, ML-7 82%). Median PFS (months) was prolonged with RIB vs placebo in pts without a RIB dose reduction (ML-2: 27.7 vs 16.0; ML-3: not reached [NR] vs 18.3; ML-7: 23.8 vs 13.8); median PFS in pts with ≥1 RIB dose reduction was: ML-2 25.3, ML-3 NR, and ML-7 27.5 months. In pts with measurable disease and without a RIB dose reduction, ORR was 46% (ML-2), 43% (ML-3), and 48% (ML-7); CBR was 70%, 68%, and 79%, respectively. In pts with measurable disease and ≥1 RIB dose reduction, ORR was 62% (ML-2), 57% (ML-3), and 55% (ML-7); CBR was 88%, 85%, and 88%, respectively. The most common Grade 3/4 AEs in the RIB vs placebo groups (≥5% of pts in either ML trial, irrespective of causality or dose reduction) were neutropenia (ML-2: 62% vs 1%; ML-3: 55% vs 0; ML-7: 65% vs 4%), leukopenia (ML-2: 21% vs 1%; ML-3: 12% vs 0; ML-7: 16% vs 1%), hypertension (ML-2: 13% vs 13%; ML-3: 5% vs 5%; ML-7: 2% vs 3%), increased alanine aminotransferase (ML-2: 10% vs 1%; ML-3: 10% vs 0; ML-7: 5% vs 1%), and increased aspartate aminotransferase (ML-2: 6% vs 1%; ML-3: 6% vs 0; ML-7: 4% vs 1%).

Conclusions: Results from the ML-2, -3, and -7 trials suggest that pts who start on 600 mg of RIB and require dose reduction for the management of their AEs, or for other reasons, continue to derive clinical benefit.

Citation Format: Beck JT, Neven P, Sohn J, Chan A, Sonke GS, Bachelot T, Campos-Gomez S, Martin M, Bardia A, Alam J, Miller M, Diaz-Padilla I, Kong O, Hart L. Ribociclib treatment benefit in patients with advanced breast cancer with ≥1 dose reduction: Data from the MONALEESA-2, -3, and -7 trials [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 P6-18-06.

Abstract P2-05-07: Whole exome sequencing of extreme responders reveals low mutation burden in metastatic breast cancer

Background: Extreme responders to anticancer therapy are rarely encountered in the treatment of advanced breast cancer patients, but their treatment response have not been investigated on the whole exome level. We performed whole exome analysis to characterize genomic landscape of extreme responders in metastatic breast cancer patients.

Methods: Clinical samples were obtained from patients who showed exceptional response to anti-HER2 therapy or hormonal therapy. Non-responders were selected among those who did not respond. Matched breast tumor tissue (somatic DNA) and blood samples (germline DNA) were collected from a total of 18 responders (12 ER+, 6 HER2+) and 8 non-responders (6 ER+, 1 HER2+, 1 TNBC). Whole exome sequencing using Illumina HiSeq2500 was performed on the 26 patients (52 samples). Somatic single nucleotide variants (SNVs), indels and copy number variants (CNVs) were identified for each patient genome. Group specific somatic variants and mutation burden were statistically analyzed.

Findings: Cancer exomes were characterized by 1,455 somatic single-nucleotide variants (1,327 missense, 80 nonsense, 36 splice-site, 12 start/stop-lost), 149 insertions/deletions (108 frameshift, 41 inframe), with a median of 1 mutations per Mb (0.2 to 2.7 mutations per Mb) in all patients. Responders harbored a significantly lower non-synonymous mutation burden than non-responders (median, 27 vs. 90.5, P=0.01), and copy number variation burden was also lower (median 23 vs. 31, P=0.14). Multivariate analyses of factors influencing progression-free survival showed that high mutation burden and visceral metastases were significantly related with progression.

Interpretation: Extreme responders of metastatic breast cancer are characterized by low nonsynonymous mutational burden.

Citation Format: Sohn J, Lim SM, Kim E, Kim S, Koo JS, Kim SI, Park S, Park HS, Kwon N-J, Kim GM, Kim S. Whole exome sequencing of extreme responders reveals low mutation burden in metastatic breast cancer [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 P2-05-07.

Abstract PD6-12: Withdrawn

This abstract was withdrawn by the authors.

Abstract P1-08-03: Withdrawn

This abstract was withdrawn by the authors.

Abstract P4-22-13: Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1

Background

Everolimus (EVE), an mTOR inhibitor has shown activity in HER2+ advanced breast cancer (ABC) in both preclinical and clinical studies. In the pivotal BOLERO-1 trial (NCT00876395), the progression-free survival (PFS) was not significantly different between the EVE + trastuzumab (TRAS) + paclitaxel (PAC) combination and placebo (PBO) + TRAS + PAC in the full HER2+ population (EVE, 15.0 mo vs PBO, 14.5 mo; HR=0.89; 95% CI: 0.73-1.08; p=0.1166). Although not reaching protocol defined level for statistical significance, the hormone receptor negative (HR-) subpopulation appeared to benefit from EVE, with a 7.2 mo PFS benefit vs PBO arm (EVE, 20.3 mo vs PBO, 13.1 mo; HR=0.66; 95% CI: 0.48-0.91; p=0.0049). The final exploratory overall survival (OS) analysis from the study is presented here.

Methods

In this phase 3 randomized trial, 719 women with HER2+ ABC without prior TRAS or chemotherapy in the metastatic setting were randomized 2:1 to receive either EVE (10 mg/d) or placebo (PBO) and weekly PAC+TRAS, stratified by visceral metastasis (lung, liver, peritoneal or pleural: yes vs no) and prior adjuvant or neo-adjuvant treatment with TRAS (yes vs no). As the primary objectives (PFS on full population and on HR- subpopulation) of BOLERO-1 were not met, the key secondary endpoint of OS was not formally statistically tested. However, given the results of PFS, in particular in the HR- subpopulation, a change to the OS analysis plan was made by introducing one final exploratory OS analysis at the time of study termination.

Results

At data cutoff (Dec 31, 2015), the median duration of exposure was 40.8 weeks (range: 0.6-320.4) in the EVE arm and 48.1 weeks (range: 1.1-308.0) in the PBO arm. After a median follow-up of 60.3 mo, 350 deaths were recorded in the full population, 238 (49.6%) in the EVE arm and 112 (46.9%) pts in the PBO arm. In the full population, the median OS was comparable in the EVE vs PBO arms (48.6 mo vs 50.0 mo respectively; HR = 1.13; 95% CI: 0.90-1.42). In the HR- subpopulation, 138 deaths were recorded; 88 (42.3%) pts in the EVE arm and 50 (48.5%) pts in the PBO arm. In the HR- subpopulation, the median OS in the EVE arm was longer compared to PBO arm (57.0 mo vs 41.6 mo respectively; HR = 0.83; 95% CI: 0.59-1.18). Stomatitis, diarrhea, alopecia, cough, rash, pyrexia, neutropenia, and fatigue were the most frequent adverse events (AEs) reported in EVE arm (≥35%). AEs leading to dose interruption and/or change were reported in 441 (93.4%) pts in EVE arm and 165 (69.3%) pts in the PBO arm respectively. Overall, AEs leading to treatment discontinuation were reported in 262 (55.5%) pts in EVE arm and 98 (41.2%) pts in PBO arm. Serious AEs were reported in 171 (36.2%) pts in the EVE arm and 40 (16.8%) pts in the PBO arm respectively. On treatment AE related deaths were reported for 3.6% pts in the EVE arm and 0% pts in the PBO arm.

Conclusions

The median OS was similar in the EVE vs PBO arms for overall population. However, a prolongation of 15.4 mo in median OS of HR- subpopulation was observed in the EVE arm vs PBO arm in this exploratory analysis. Pts in the EVE arm had a manageable safety, consistent with the safety profile of EVE and no new safety signals were identified.

Citation Format: Yardley D, Hurvitz S, Jiang Z-f, Toi M, Burris H, Buyse M, Slamon D, Makhson A, Elsaid A, Lerzo G, Hellerstedt B, Nuzzo F, Sohn J, Manzyuk L, Cabaribere D, Lincy J, Weimann A, Noel-Baron F, Pacaud L, Andre F. Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-13.