Abstract PD1-08: High-throughput genome analysis and therapeutic decision for patients with HER2-negative metastatic breast cancer: First feasibility and molecular results of the randomized phase II study SAFIR02 BREAST (UCBG-0105/1304)

Background A genomic-driven therapeutic strategy in metastatic breast cancer (MBC) was recently demonstrated as feasible in the clinical practice, but its actual impact on patient outcome remains elusive. SAFIR02 study is an ongoing national multicentric phase II randomized trial evaluating targeted therapies matching specific genomic alterations (GA) administered as maintenance after objective response and/or stable disease obtained with chemotherapy in HER2-negative MBC patients. This analysis reports on feasibility of the procedure and the rate of identified actionable targets.

Methods Eligible MBC patients (PS=0/1, first- or second-line of chemotherapy, HER2-negative/hormone receptor (HR)-negative or endocrine resistant HR-positive; measurable per RECIST 1.1; accessible to tumor biopsy; no bone metastases-only disease, no major organ dysfunction) were subjected to tumor biopsy for genomic analysis (CGH arrays, Affymetrix Cytoscan; NGS, Ion Torrent PGM, AmpliSeq, panel of around 50 genes). Actionable GA were identified and corresponding targeted therapies were proposed by a multidisciplinary tumor board (MTB). Patients received cytotoxic-based treatment at physician's choice and those with stable or responding disease after 6 to 8 cycles (or at least 4 if stopped for toxicity reason) and targetable GA, were offered randomization between targeted therapy or chemotherapy maintenance until progression or intolerance (main study). Since January 2016, an amendment was made to propose to patients without targetable alteration a randomization between anti-PD-L1 (MEDI4736) or standard chemotherapy maintenance (substudy).

Results Between March 2014 and May 2016, 457 patients have been enrolled at 21 centers. Genomic analyses could not be obtained in 107 cases (23%) due to either biopsy failure (n= 40; 9%) or low cellularity (n=67; 14%). Of the 307 patients reviewed by the MTB, 197 (64%) had an actionable GA, including PIK3CA-PIK3CB-PIK3R1 (n=51), FGF4 or FGFR1/2 (n= 42), BRCA1/2 (n=15), AKT1/2/3 (n=13), BRAF/KRAS/NRAS (n=13), HER2/3 (n=10), NF1-FRS2 (n=10), MTOR-RPTOR-TSC2 (n=8), PTEN (n=7), STK11 (n=7), IGF1R (n=7), EGFR (n=5). Therapeutic proposals by MTB included AZD5363 (n=71), AZD4547 (n=42), AZD2014 (n=23), selumetinib (n=23), olaparib (n=16), AZD8931 (n=15), vandetanib (n=5), bicalutamide (n=2). In an exploratory analysis involving 157 patients, the rate of targeted therapy proposal by MTB markedly differed between triple-negative patients (TNBC; 24 of 48, 50%) and HER2-negative/HR-positive patients (92 of 109, 84%; p=6.14. 10-6, Chi-2 test). At the time of the analysis, 85 patients have been randomized (main study, 68; substudy, 17). Causes of randomization failure (n=108) included disease progression (n=45) or death (n=25), non-eligibility criteria (n=27), patient/physician's decision (n=11).

Conclusion A large number of patients had identified targetable GA. Of note, the rate of targeted therapeutic proposal was significantly lower in TNBC than in HER2-negative/HR-positive patients. Rapidly progressing disease may impede ultimate randomization.

Citation Format: Gonçalves A, Bachelot T, Lusque A, Arnedos M, Campone M, Bièche I, Lacroix L, Pierron G, Dalenc F, Filleron T, Sablin M-P, Jimenez M, Ferrero J-M, Lefeuvre-Plesse C, Bonnefoi H, Attignon V, Soubeyran I, Jezequel P, Commo F, André F. High-throughput genome analysis and therapeutic decision for patients with HER2-negative metastatic breast cancer: First feasibility and molecular results of the randomized phase II study SAFIR02 BREAST (UCBG-0105/1304) [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 PD1-08.

Abstract P4-22-05: First-line ribociclib plus letrozole in patients with de novo HR+, HER2– advanced breast cancer (ABC): A subgroup analysis of the MONALEESA-2 trial

Background: Around 15,000 US patients per year are diagnosed with de novo ABC. Due to the absence of prior systemic treatment for breast cancer, tumors of patients with de novo ABC may exhibit a different disease biology, which could result in different tumor responses compared with patients who have relapsed breast cancer. Ribociclib is an orally bioavailable cyclin-dependent kinase (CDK) 4/6 inhibitor. Results from MONALEESA-2, a double-blind, placebo-controlled, randomized Phase 3 trial (NCT01958021), demonstrated that first-line therapy with ribociclib + letrozole significantly improved progression-free survival (PFS) vs placebo + letrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) ABC. Many patients with de novo ABC receive endocrine therapy in the first line and in subsequent lines; here we present results from the MONALEESA-2 study in a subpopulation of patients with de novo ABC.

Methods: Postmenopausal women (N=668) with HR+, HER2– ABC who had no prior systemic therapy for ABC were randomized 1:1 (stratified by liver and/or lung metastases) to receive ribociclib (600 mg/day; 3-weeks-on/1-week-off) + letrozole (2.5 mg/day; continuous) or placebo + letrozole. Patients with de novo ABC were eligible. Additional eligibility criteria included measurable disease or ≥1 predominantly lytic bone lesion, Eastern Cooperative Oncology Group performance status ≤1, and adequate bone marrow/organ function. Prior CDK4/6 inhibitors or systemic therapy for ABC were prohibited. Patients may have received ≤14 days of letrozole or anastrozole for ABC. The primary endpoint was locally assessed PFS; a predefined subgroup analysis evaluated PFS in patients with de novo ABC.

Results: In total, 227 patients with de novo ABC were enrolled. Patients with de novo ABC were equally distributed with 114 (34%) and 113 (34%) in the ribociclib + letrozole and placebo + letrozole arms, respectively. Median duration of exposure to study treatment in the ribociclib + letrozole vs placebo + letrozole arms was 14.1 vs 12.8 months. Treatment was discontinued in 84 (37%) patients with de novo ABC (ribociclib + letrozole vs placebo + letrozole, n [%]; 34 [30%] vs 50 [44%]). Reasons for treatment discontinuation (ribociclib + letrozole vs placebo + letrozole, n [%]) included disease progression (21 [18%] vs 41 [36%]), patient/physician decision (5 [4%] vs 6 [5%]), and adverse events (6 [5%] vs 3 [3%]). PFS was increased in patients with de novo ABC who received ribociclib + letrozole vs placebo + letrozole (hazard ratio=0.448 [95% confidence interval: 0.267–0.750]). The 12-month PFS event-free probability in patients with de novo ABC was 82% in the ribociclib + letrozole arm vs 66% in the placebo + letrozole arm.

Conclusions: The combination of ribociclib + letrozole significantly improved PFS compared with placebo + letrozole in postmenopausal women with HR+, HER2– de novo ABC at diagnosis and therefore may become an important treatment option in the de novo ABC setting.

Keywords: Advanced breast cancer; CDK4/6 inhibitor; Letrozole; Ribociclib

Citation Format: O'Shaughnessy J, Petrakova K, Sonke GS, André F, Conte P, Arteaga CL, Cameron DA, Hart LL, Villanueva C, Jakobsen EH, Lindquist D, Souami F, Li X, Germa C, Hirawat S, Hortobagyi GN. First-line ribociclib plus letrozole in patients with de novo HR+, HER2– advanced breast cancer (ABC): A subgroup analysis of the MONALEESA-2 trial [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 P4-22-05.

Consensus on precision medicine for metastatic cancers: a report from the MAP conference

Recent advances in biotechnologies have led to the development of multiplex genomic and proteomic analyses for clinical use. Nevertheless, guidelines are currently lacking to determine which molecular assays should be implemented in metastatic cancers. The first MAP conference was dedicated to exploring the use of genomics to better select therapies in the treatment of metastatic cancers. Sixteen consensus items were covered. There was a consensus that new technologies like next-generation sequencing of tumors and ddPCR on circulating free DNA have convincing analytical validity. Further work needs to be undertaken to establish the clinical utility of liquid biopsies and the added clinical value of expanding from individual gene tests into large gene panels. Experts agreed that standardized bioinformatics methods for biological interpretation of genomic data are needed and that precision medicine trials should be stratified based on the level of evidence available for the genomic alterations identified.

Quality of life with palbociclib plus fulvestrant in previously treated hormone receptor-positive, HER2-negative metastatic breast cancer: patient-reported outcomes from the PALOMA-3 trial

In treating HR+, HER2− metastatic breast cancer, novel agents that enhance endocrine therapy activity but do not worsen quality of life (QoL) are clinically desired. Patient-reported outcomes data from the PALOMA-3 study suggest palbociclib plus fulvestrant allow patients to maintain good QoL in the endocrine resistance setting while experiencing a substantially delayed disease progression.

Background

In the PALOMA-3 study, palbociclib plus fulvestrant demonstrated improved progression-free survival compared with fulvestrant plus placebo in hormone receptor-positive, HER2− endocrine-resistant metastatic breast cancer (MBC). This analysis compared patient-reported outcomes (PROs) between the two treatment groups.

Patients and methods

Patients were randomized 2 : 1 to receive palbociclib 125 mg/day orally for 3 weeks followed by 1 week off (n = 347) plus fulvestrant (500 mg i.m. per standard of care) or placebo plus fulvestrant (n = 174). PROs were assessed on day 1 of cycles 1–4 and of every other subsequent cycle starting with cycle 6 using the EORTC QLQ-C30 and its breast cancer module, QLQ-BR23. High scores (range 0–100) could indicate better functioning/quality of life (QoL) or worse symptom severity. Repeated-measures mixed-effect analyses were carried out to compare on-treatment overall scores and changes from baseline between treatment groups while controlling for baseline. Between-group comparisons of time to deterioration in global QoL and pain were made using an unstratified log-rank test and Cox proportional hazards model.

Results

Questionnaire completion rates were high at baseline and during treatment (from baseline to cycle 14, ≥95.8% in each group completed ≥1 question on the EORTC QLQ-C30). On treatment, estimated overall global QoL scores significantly favored the palbociclib plus fulvestrant group [66.1, 95% confidence interval (CI) 64.5–67.7 versus 63.0, 95% CI 60.6–65.3; P = 0.0313]. Significantly greater improvement from baseline in pain was also observed in this group (−3.3, 95% CI −5.1 to −1.5 versus 2.0, 95% CI −0.6 to 4.6; P = 0.0011). No significant differences were observed for other QLQ-BR23 functioning domains, breast or arm symptoms. Treatment with palbociclib plus fulvestrant significantly delayed deterioration in global QoL (P < 0.025) and pain (P < 0.001) compared with fulvestrant alone.

Conclusion

Palbociclib plus fulvestrant allowed patients to maintain good QoL in the endocrine resistance setting while experiencing substantially delayed disease progression.

Clinical Trial Registration

NCT01942135.

Abstract MS2-2: Genomics to personalize therapy of metastatic breast cancers

Genomic studies have shown that breast cancer includes large number of rare genomic segments. This led to the development of precision medicine where sequencing could be used to identify drivers in individuals, that would be treated accordingly. 10 to 20 molecular alterations are being investigated in the context of biomarker-driven therapeutic trials. This includes PIK3CA, AKT1, ERBB2, PTEN, BRCA1/2, ESR1 mutations, FGFR1, CCND1 amplifications, AR expression. Beyond the question of clinical utility of detecting these variants, there are several challenges that precision medicine is facing in breast cancer.

The first challenge will be to better define which genomic alterations are drivers in individuals and how to target them. The recent failures of prospective trials testing precision medicine (SAFIR01, SHIVA) highlights the need to better understand what defines a targetable alteration. These trials also pointed out the need to target the molecular alterations, rather than the pathway. Also, it's important to better understand the role that alterations on multiple drivers could play on resistance. As illustration, several reports suggest that PIK3CA mutations could be associated to a lower sensitivity to dual Her2 inhibition in neoadjuvant setting.

The second challenge will be to generate genomic tests that predict the sensitivity of therapies that target pathways, like mTOR or CDK4 inhibitors. To this regards, gene expression looks particularly attractive since it allows quantifying pathway activation.

The third challenge will be to predict earlier the resistance to targeted therapies. The development of circulating DNA as a diagnostic tool could be useful for early diagnosis of resistance. Clinical trials testing this technology are currently starting.

Finally, one of the major challenge will be to integrate immunotherapeutics in the application field of precision medicine. High mutational loads and neoantigen expression could predict efficacy of immunotherapeutics. Further combination with targeted therapies should be rationalized based on genomics.

Overall, while candidate biomarkers exist and technologies are available, precision medicine failed to deliver until now for patients with metastatic breast cancer. Nevertheless, ongoing randomized trials testing drugs according to genomic alterations should open the door of treatment decisions based on genomics for breast cancer patients.

Citation Format: André F. Genomics to personalize therapy of metastatic breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr MS2-2.

EGFR-independent mechanisms of acquired resistance to AZD9291 in EGFR T790M-positive NSCLC patients

BACKGROUND

AZD9291 is an oral, irreversible, mutant-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKI), which specifically targets both sensitizing and resistant T790M mutations. This compound has shown outstanding activity, in a phase I/II (AURA) trial. However, despite impressive tumor responses in T790M-positive patients, acquired resistance to this drug limits the benefit of this compound. Mutations at the EGFR C797 codon, located within the kinase-binding site, were very recently reported to be a potential mechanism of resistance to AZD9291 in T790M-positive patients.

PATIENTS AND METHODS

To identify potential mechanisms of resistance to AZD9291, we report here on two patients with resistant biopsy specimens that had been treated with AZD9291.

RESULTS

We identified in two distinct cases, HER2 and MET amplification by FISH and CGH as a potential mechanism of acquired resistance to third-generation EGFR-TKI. Interestingly, this event occurred with complete loss of the T790M mutation. In one case, we observed a different molecular status at two biopsy sites (the T790M mutation at the primary site and wild-type T790M at the metastatic site with different pathways of acquired resistance to AZD9291).

CONCLUSION

Our observations suggest that T790M-positive and wild-type T790M clones may coexist at baseline. AZD9291 efficiently suppresses the growth of T790M-positive cells, but a population of wild-type T790M cells at baseline will mediate the development of resistance, here via a by-pass pathway activating either HER2 or MET.

Impact of centralization on aCGH-based genomic profiles for precision medicine in oncology

BACKGROUND

Comparative genomic hybridization (CGH) arrays are increasingly used in personalized medicine programs to identify gene copy number aberrations (CNAs) that may be used to guide clinical decisions made during molecular tumor boards. However, analytical processes such as the centralization step may profoundly affect CGH array results and therefore may adversely affect outcomes in the precision medicine context.

PATIENTS AND METHODS

The effect of three different centralization methods: median, maximum peak, alternative peak, were evaluated on three datasets: (i) the NCI60 cell lines panel, (ii) the Cancer Cell Line Encyclopedia (CCLE) panel, and (iii) the patients enrolled in prospective molecular screening trials (SAFIR-01 n = 283, MOSCATO-01 n = 309), and compared with karyotyping, drug sensitivity, and patient-drug matching, respectively.

RESULTS

Using the NCI60 cell lines panel, the profiles generated by the alternative peak method were significantly closer to the cell karyotypes than those generated by the other centralization strategies (P < 0.05). Using the CCLE dataset, selected genes (ERBB2, EGFR) were better or equally correlated to the IC50 of their companion drug (lapatinib, erlotinib), when applying the alternative centralization. Finally, focusing on 24 actionable genes, we observed as many as 7.1% (SAFIR-01) and 6.8% (MOSCATO-01) of patients originally not oriented to a specific treatment, but who could have been proposed a treatment based on the alternative peak centralization method.

CONCLUSION

The centralization method substantially affects the call detection of CGH profiles and may thus impact precision medicine approaches. Among the three methods described, the alternative peak method addresses limitations associated with existing approaches.

Abstract P3-15-03: Safety analysis of BOLERO-3: A phase 3 trial of daily everolimus (EVE) vs placebo (PBO), both with weekly trastuzumab (TRAS) and vinorelbine in trastuzumab-resistant, advanced breast cancer

Background: Activation of the PI3K/mTOR pathway is thought to be involved in resistance to TRAS. BOLERO-3 is a randomized phase 3, double-blind, placebo-controlled, international, clinical trial evaluating the addition of the mTOR inhibitor EVE (5 mg/day) to TRAS plus vinorelbine (25 mg/m2) in patients with HER2+ advanced breast cancer resistant to TRAS and who were previously treated with a taxane. A total of 569 adult women were randomized 1:1 to receive EVE (n = 284) or PBO (n = 285). Study treatment represented the 2nd, 3rd, or 4th line of chemotherapy-containing regimen for 83% of patients in the metastatic setting. The primary endpoint, progression-free survival based on local radiologic assessment, was significantly longer in the EVE arm versus PBO (HR = 0.78; P = .0067) at a median follow-up of 20 months.

Methods: Study drugs were continued until disease progression or unacceptable toxicity. Incidences of adverse events (AEs) were monitored continuously. Dose modifications and discontinuations were recorded.

Results: The median duration of exposure to study treatment was similar across treatment groups: 24.8 weeks for EVE, 25.1 weeks for TRAS, and 24.0 weeks for vinorelbine (EVE arm); and 22.9 weeks for PBO, 24.0 weeks for TRAS, and 23.1 weeks for vinorelbine (PBO arm). The AEs were consistent with known drug-safety profiles. Class-effect AEs with mTOR inhibitors (including stomatitis, rash, noninfectious pneumonitis, and hyperglycemia) were higher in the EVE arm and were mainly grade 1/2. Grade 3 class-effect AEs each occurred in &lt;15% of patients (stomatitis [13%], hyperglycemia [2%], and noninfectious pneumonitis [&lt;1%]). Grade 4 noninfectious pneumonitis (&lt;1%) was uncommon; there were no grade 4 events of stomatitis or hyperglycemia, and no grade 3/4 events of rash. The incidence and grade of hematologic AEs were increased in the EVE arm vs the PBO arm, including all grade neutropenia (81% vs 70%), anemia (49% vs 29%), febrile neutropenia (17% vs 4%) and thrombocytopenia (14% vs 2%); grade 3/4 hematologic AEs included neutropenia (grade 3: 35% vs 32%; grade 4: 38% vs 30%), anemia (grade 3: 17% vs 6%; grade 4: 2% vs &lt;1%), febrile neutropenia (grade 3: 11% vs 3%; grade 4: 5% vs 1%), and thrombocytopenia (grade 3: 3% vs &lt;1%; grade 4: 1% vs 0). The incidences and grades of changes in liver enzymes and hyperlipidemia were similar between arms. Serious AEs were reported in 42% of patients in the EVE arm and 20% of patients in the PBO arm (26% and 6% were attributed to study treatments, respectively). A higher percentage of patients discontinued treatment because of AEs in the EVE arm versus PBO (10% vs 5%). In all, 83% of patients required at least 1 EVE dose interruption and/or reduction; 96% of these were attributed to AEs. There were fewer deaths in the EVE arm (37%) compared with PBO (41%).

Conclusions: The safety of the combination of EVE, TRAS, and vinorelbine was considered manageable in this heavily pretreated patient population. Overall, the results from BOLERO-3 demonstrate that EVE can be combined with TRAS and chemotherapy to improve efficacy in TRAS-resistant HER2+ advanced breast cancer previously treated with a taxane.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-15-03.