Abstract S3-03: PAM50 intrinsic subtype as a predictor of pathological complete response following neoadjuvant dual HER2 blockade without chemotherapy in HER2-positive breast cancer: First results of the PAMELA clinical trial

Background: Prior neoadjuvant studies in HER2+ breast cancer have shown that dual HER2 blockade without chemotherapy achieves pathological complete responses (pCR) rates of 6-36% (TBCRC006/TBCRC023/NeoSphere). However, a major challenge today is how to select prospectively patients who will derive the maximum benefit from dual anti-HER2 therapies without chemotherapy. In this context, we and others have previously shown that HER2+ disease is biologically heterogeneous and composed of all the intrinsic molecular subtypes (Luminal A, Luminal B, HER2-enriched [HER2-E] and Basal-like). Among them, the HER2-E subtype shows the highest activation of the EGFR/HER2 pathway.

Methods: PAMELA (NCT01973660) is a non-randomized, open-label, multicentric, prospective translational research study in stage I-IIIA HER2+ breast cancer designed to evaluate the ability of the PAM50 intrinsic subtypes to predict pCR in the breast (pCRB; in situ allowed) following 18 weeks of neoadjuvant lapatinib and trastuzumab). Patients with HR+ disease received letrozole (if postmenopausal) or tamoxifen (if pre-menopausal). The primary objective was to compare the pCRB rates of the HER2-E versus the non-HER2-E subtypes in the intent-to-treat population. The study was planned with a power of 95% at a significance level of 0.05 to detect an absolute relative difference in pCRB rates between the two groups of 27% (i.e. 35% in HER2E and 8% in non-HER2-E). Day-15 formalin-fixed, paraffin-embedded tissue samples were prospectively collected and gene expression profiled using the nCounter platform. The intrinsic subtypes were identified using the research-based PAM50 predictor (Parker JCO 2009).

Results: A total of 151 patients were recruited (n=77 HR+ and n=74 HR-). Patient characteristics were: mean age (55 years), mean tumor size (2.84 cm), negative axilla (63.5%) and postmenopausal (60.2%). At baseline, intrinsic subtype distribution was: HER2-E (n=101, 66.9%), Luminal A (n=22; 14.6%), Luminal B (n=16; 10.6%), Basal-like (n=9; 6%) and Normal-Like (n=3; 2%). The overall pCRB was 30.5% (46/151), 18.2% in HR+ disease and 43.2% in HR- disease. Five patients (3.3%) presented progressive disease. Rates of pCRB in HER2-E and non-HER2-E subtypes were 40.6% and 10.0% (p<0.0001), respectively. HER2-E subtype predicted pCRB independently of HR status. Within HR+ disease, pCRB rates were 31.6% in HER2-E subtype and 5.3% in non-HER2-E subtype (p=0.006). Within HR- disease, pCRB rates were 46.0% in HER2-E subtype and 27.3% in non-HER2-E subtypes (p=0.331). At Day-15, the majority of tumors became Normal-like (48.9%) or Luminal A (27.5%). Rates of pCRB were 46.9% in Normal-like tumors and 11.9% in non-Normal-like tumors when evaluated at day-15 (p<0.0001).

Conclusions: The PAMELA trial met its primary endpoint. PAM50 HER2-E subtype identifies patients with HER2+ disease likely to derive a large benefit from dual anti-HER2 therapies +/- endocrine therapy, especially in HER2+/HR+ disease. In addition, early changes in gene expression indicative of a reduction of tumor cellularity are predictive of pathological complete response at surgery.

Citation Format: Prat Aparicio A, Cortes Castan J, Pare L, Galvan P, Bermejo B, Martínez N, Vidal M, Pernas S, López R, Muñoz M, Nuciforo P, Fasani R, Morales S, Oliveira M, de La Peña L, Peláez A, Llombart A. PAM50 intrinsic subtype as a predictor of pathological complete response following neoadjuvant dual HER2 blockade without chemotherapy in HER2-positive breast cancer: First results of the PAMELA clinical 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 S3-03.

Relation between plasma trough concentration of abiraterone and prostate-specific antigen response in metastatic castration-resistant prostate cancer patients

BACKGROUND

Abiraterone (ABI) is a major oral agent for the treatment of metastatic castration-resistant prostate cancer (mCRPC) patients but its systemic exposure is subject to a large inter-individual variability. We aimed to explore the relationship between ABI trough plasma concentration and prostate-specific antigen (PSA) response in mCRPC patients and to identify the critical determinants for its activity.

PATIENTS AND METHODS

This is a monocentric prospective observational study in mCRPC patients treated with ABI. The plasmatic concentration of ABI at steady state was measured using liquid chromatography with fluorescence detection. The primary objective was to study the relationship between mean ABI plasma exposure (ABI C_min) and 3-month PSA response.

RESULTS

From 2012 to 2016, 61 mCRPC patients were eligible for pharmacokinetic/pharmacodynamic assessment. Thirty-eight patients experienced PSA response (62%, [confidence interval {CI} 95% 50-78]). In univariate analysis, ABI C_min was 1.5-fold higher in responders: 12.0 ng/mL (CI 95% 9.4-15.6) versus 8.0 ng/mL (CI 95% 5.8-11.6; P = 0.0015). In multivariate analysis, only ABI C_min was independently associated with PSA response (odds ratio = 1.12 [CI 95% 1.01-1.25], P = 0.004). By receiver operating characteristic analysis, the optimal threshold for ABI C_min was 8.4 ng/mL. Progression-free survival (PFS) was significantly higher in patients with ABI C_min above 8.4 ng/mL (hazard ratio 0.55, [CI 95% 0.31-0.99], 12.2 [CI 95% 9.2-19.5] versus 7.4 [CI 95% 5.5-14.7] months otherwise, P = 0.044).

CONCLUSIONS

We showed that ABI trough concentration correlates with PSA response and PFS. Moreover, we could determine a cut-off value of plasmatic concentration for PSA response. Altogether, ABI concentration monitoring appears as a new approach to improve clinical outcome in mCPRC patients.

Neuropsychological alterations and neuroradiological findings in patients with post-traumatic concussion: Results of a pilot study

INTRODUCTION

Mild traumatic brain injury (mTBI) has traditionally been considered to cause no significant brain damage since symptoms spontaneously remit after a few days. However, this idea is facing increasing scrutiny. The purpose of this study is to demonstrate the presence of early cognitive alterations in a series of patients with mTBI and to link these findings to different markers of brain damage.

METHODS

We conducted a prospective study of a consecutive series of patients with mTBI who were evaluated over a 12-month period. Forty-one (3.7%) of the 1144 included patients had experienced a concussion. Patients underwent a routine clinical evaluation and a brain computed tomography (CT) scan, and were also administered a standardised test for post-concussion symptoms within the first 24hours of mTBI and also 1 to 2 weeks later. The second assessment also included a neuropsychological test battery. The results of these studies were compared to those of a control group of 28 healthy volunteers with similar characteristics. Twenty patients underwent an MRI scan.

RESULTS

Verbal memory and learning were the cognitive functions most affected by mTBI. Seven out of the 20 patients with normal CT findings displayed structural alterations on MR images, which were compatible with diffuse axonal injury in 2 cases.

CONCLUSIONS

Results from this pilot study suggest that early cognitive alterations and structural brain lesions affect a considerable percentage of patients with post-concussion syndrome following mTBI.

Vemurafenib pharmacokinetics and its correlation with efficacy and safety in outpatients with advanced BRAF-mutated melanoma

Vemurafenib is a BRAF kinase inhibitor approved for first-line treatment of metastatic BRAF (V600) -mutant melanoma. However, data on the pharmacokinetic/pharmacodynamic (PK/PD) relationship are lacking. The aim of this prospective, multicenter study was to explore the PK/PD relationship for vemurafenib in outpatients with advanced BRAF-mutated melanoma. Fifty-nine patients treated with single-agent vemurafenib were prospectively analyzed. Vemurafenib plasma concentration (n = 159) was measured at days 15, 30, 60, and 90 after treatment initiation. Clinical and biological determinants (including plasma vemurafenib concentration) for efficacy and safety were assessed using Cox's model and multivariate stepwise logistic regression. Median progression-free survival (PFS) and overall survival were 5.0 (95 % confidence interval [95 % CI] 2.0-6.0) and 11.0 (95% CI 7.0-16.0) months, respectively. Twenty-nine patients (49 %) experienced any grade ≥3 toxicity and the most frequent grade ≥2 toxicity was skin rash (37 %). Severe toxicities led to definitive discontinuation in seven patients (12 %). Grade ≥2 skin rash was not statistically associated with better objective response at day 60 (p = 0.06) and longer PFS (hazard ratio 0.47; 95 % CI 0.21-1.08; p = 0.075). Grade ≥2 skin rash was statistically increased in patients with ECOG  ≥ 1 (odds ratio 4.67; 95 % CI 1.39-15.70; p = 0.012). Vemurafenib concentration below 40.4 mg/L at day 15 was significantly associated with a shorter PFS (1.5 [0.5-5.5] vs. 4.5 [2-undetermined] months, p = 0.029). Finally, vemurafenib concentration was significantly greater in patients developing grade ≥2 rash (61.7 ± 25.0 vs. 36.3 ± 17.9 mg/L, p < 0.0001). These results suggest that early plasma drug monitoring may help identify outpatients at high risk of non-response or grade ≥ 2 skin rash.

Long-term outcome of insulin pump therapy: reduction of hypoglycaemia and impact on glycaemic control

AIMS

To determine the long-term outcome of continuous subcutaneous insulin infusion (CSII) in Type 1 diabetes according to Catalan National Health Service indications.

METHODS

Retrospective observational study including 178 patients with Type 1 diabetes who started CSII treatment in our centre (2003-2008). All patients were followed in our CSII programme for outpatients for at least 5 years. Data on annual HbA1c levels were collected, and the main indication for starting CSII was analysed.

RESULTS

Twenty-seven of 178 patients were excluded because of loss to follow-up or withdrawal from CSII, thus 151 patients (aged 37.4 ± 10.5 years, 64% women) were analysed. The main indications for starting CSII were suboptimal metabolic control (60.9%), severe hypoglycaemia/hypoglycaemia unawareness (25.5%) and others (13.6%). HbA1c was 64 ± 13 mmol/mol (8.0 ± 1.2%) at the start of CSII and 62 ± 13 mmol/mol (7.8 ± 1.2%) after 5 years in the total cohort (P = 0.1). The severe hypoglycaemia rates were 0.66 ± 1.61 and 0.17 ± 0.42 episodes/patient/year (P < 0.001). In patients with suboptimal metabolic control, HbA1c decreased from 68 ± 12 mmol/mol (8.4 ± 1.1%) to 64 ± 14 mmol/mol (8.0 ± 1.3%) (P = 0.016), with 37.4% of those in this group having an HbA1c ≤ 58 mmol/mol (7.5%) after 5 years. In patients starting CSII due to severe hypoglycaemia the problem was considered resolved in 93%, and in 64% of those starting CSII because of suboptimal glycaemic control, HbA1c improved significantly.

CONCLUSIONS

CSII therapy achieves and maintains its efficacy mainly in terms of reducing severe hypoglycaemia. In the whole group of patients, the reduction in HbA1c is transient and disappears after 5 years.

Effect of ageing on the availability of heavy metals in soils amended with compost and biochar: evaluation of changes in soil and amendment properties

Remediation strategies using soil amendments should consider the time dependence of metal availability to identify amendments that can sustainably reduce available pollutant concentrations over time. Drying-wetting cycles were applied on amendments, soils and soil + amendment mixtures, to mimic ageing at field level and investigate its effect on extractable Cd, Cu, Ni, Pb and Zn concentrations from three contaminated soils. The amendments investigated were municipal waste organic compost and biochars. The amendments, soils and mixtures were characterised by their physicochemical properties at different ageing times. The amendments were also characterised in terms of sorption capacity for Cd and Cu. The sorption capacity and the physicochemical properties of the amendments remained constant over the period examined. When mixed with the soils, amendments, especially the compost, immediately reduced the extractable metals in the soils with low pH and acid neutralisation capacity, due to the increase in pH and buffering capacity of the mixtures. The amendments had a relatively minor impact on the metal availability concentrations for the soil with substantially high acid neutralisation capacity. The most important changes in extractable metal concentrations were observed at the beginning of the experiments, ageing having a minor effect on metal concentrations when compared with the initial effect of amendments.

Happy@feet application for the management of diabetic foot osteomyelitis

OBJECTIVE

We aimed to develop and implement an application that could improve the management of patients presenting with diabetic foot osteomyelitis.

PATIENTS AND METHODS

Physicians from the multidisciplinary diabetic foot infection team and a software engineer first assessed the needs required for the infection management and application. An experimental version was then designed and progressively improved. A final version was implemented in clinical practice in 2013 by the multidisciplinary diabetic foot infection team of our university hospital.

RESULTS

The application, known as Happy@feet, helps gather and allows access to all required data for patient management, dispenses prescriptions (antibiotics, nursing care, blood tests), and helps follow the evolution of the wound. At the end of the consultation, a customizable letter is generated and may be directly sent to the persons concerned. This application also facilitates clinical and economic research. In 2014, Happy@feet was used to follow 83 patients during 271 consultations, 88 of which were day care hospitalizations.

CONCLUSION

The Happy@feet application is useful to manage these complex patients. Once the learning period is over, the time required for data collection is compensated by the rapid dispense of prescriptions and letters. Happy@feet can be used for research projects and will be used in a remote patient management project.

[Indications and results for protontherapy in cancer treatments]

Purpose was to summarize results for proton therapy in cancer treatment. A systematic review has been done by selecting studies on the website www.pubmed.com (Medline) and using the following keywords: proton therapy, radiation therapy, cancer, chordoma, chondrosarcoma, uveal melanoma, retinoblastoma, meningioma, glioma, neurinoma, pituitary adenoma, medulloblastoma, ependymoma, craniopharyngioma and nasal cavity. There are several retrospective studies reporting results for proton therapy in cancer treatments in the following indications: ocular tumors, nasal tumors, skull-based tumors, pediatric tumors. There is no prospective study except one phase II trial in medulloblastoma. The use of proton therapy for these indications is due to dosimetric advantages offering better tumor coverage and organ at risk sparing in comparison with photon therapy. Clinical results are historically at least as efficient as photon therapy with a better toxicity profile in pediatric tumors (cognitive and endocrine functions, radiation-induced cancer) and a better tumoral control in tumors of the nasal cavity. Clinical advantages of proton therapy counterbalance its cost especially in pediatric tumors. Proton therapy could be used in other types of cancer. Proton therapy showed good outcome in ocular, nasal tumors, pediatric, skull-based and paraspinal tumors. Because of some dosimetric advantages, proton therapy could be proposed for other indications in cancer treatments.

Prevalence of aortic valve dystrophy and insufficiency in a cohort of 255 HIV-positive patients followed-up in a cardiology department between 2012 and 2014

OBJECTIVES

To study valve appearance and the presence of valve disease in a cohort of people living with HIV (PLHIV).

DESIGN

A prospective study of PLHIV examined at the cardiology department of the Clermont Ferrand university hospital group (CHU) between January 1, 2012, and December 31, 2014. Were excluded those with a history of infection associated with a possible endocarditis.

METHODS

Demographic, medical characteristics and cardiovascular disease risk factors at time of cardiovascular examination and Doppler-echocardiography were recorded and analyzed.

RESULTS

In total, 903 PLHIV were examined in the infectious diseases department, 255 of whom were included. These consisted of 67 women (26.3%) and 188 men, of a mean age of 51.2±9.7years, in whom coronary artery disease was diagnosed in 18 patients (7.0%), two women and 16 men, representing a prevalence of 3.0% in females and 8.5% in males. The appearance of the aortic cusps was considered dystrophic in 14.1% of cases (36/255), dysplastic in two cases (0.8%), exhibiting a bicuspid deformity in one case. The prevalence of aortic valve abnormality was therefore 6.0% in the women (4/67) and 17.0% in the men (32/188). On facing off this data with the Kora Monica study findings, an increase in prevalence appears only to truly manifest after 50years of age. We registered 35 aortic insufficiency cases (13.7%), representing a higher incidence than that of the Framingham cohort, with age and masculine gender being the determining factors.

CONCLUSION

Valve disease, along with coronary artery disease, should be closely monitored in PLHIV.

Abstract P6-05-02: Intrinsic subtype and gene expression changes between primary and metastatic breast cancer

Background: A better understanding of the biological changes occurring during metastatic progression of breast cancer is needed to identify new biomarkers, targets and novel treatment strategies. Here, we compared the intrinsic subtype and the expression of a gene panel across a large dataset of paired primary and metastatic tissues.

Methods: Expression profiling of 105 breast cancer-related genes was performed on 254 (127 pairs) formalin-fixed paraffin-embedded tumor tissues using the nCounter platform. Tumor samples were obtained from 3 independent sources (ConvertHER trial [BCRT 2014] and two in-house datasets). Tumors were classified into each intrinsic subtype using the research-based PAM50 classifier (Parker et al. J Clin Oncol 2009). Chi-square tests were performed to determine the differences in the distribution of variables. Paired two-class Significance of Microarrays (SAM) was performed to determine the genes differentially expressed between paired primary and metastatic tissues. In vitro stable transfection of FGFR4-GFP was performed on Luminal B MCF7 cell line. RNA was purified on control vs. transfected cell lines. 7-AAD cell viability was performed following estrogen deprivation for 6 days.

Results: Subtype distribution in primary vs. metastatic disease was 39.0% vs. 26.8% for Luminal A (p=0.012), 26.0% vs. 35.0% for Luminal B (p=0.322), 11.4% vs. 20.3% for HER2-enriched (p=0.115) and 10.6% vs. 13.0% for Basal-like tumors (p=0.843). The rate of subtype conversion was 7.7% in Basal-like, 23.1% in HER2-enriched, 30.0% in Luminal B and 54.3% in Luminal A disease. The majority of subtype conversions in Luminal A disease were to Luminal B (72.0%) and HER2-enriched (24.0%). Overall, 13.2% of primary Luminal A/B tumors progressed to a HER2-E subtype despite 70% of them being clinically HER2-negative. In a paired analysis using all samples, 10- and 12- genes were found up- and down- regulated in metastatic tissues (False Discovery Rate [FDR] &lt;5%). The up-regulated gene list in metastatic disease was composed of FGFR4 (top gene) and proliferation genes (CDC6, CCNB1, CEP55). The down-regulated gene list in metastatic disease was enriched for luminal-related genes (ESR1, PGR, NAT1 and MAPT). A similar paired analysis within Luminal A, Luminal B, HER2-enriched and Basal-like disease revealed 22, 8, 7 and 0 differentially expressed genes (FDR&lt;5%), respectively. Finally, MCF7 cell line transfected with FGFR4 showed a relative increase in the HER2-enriched profile compared with transfected control. In vitro, MCF7-FGFR4 cells showed estrogen independent growth compared to transfected controls.

Conclusions: Metastatic tissues are relatively more proliferative and less luminal compared to primary tumors. This is especially relevant in primary Luminal A disease. In contrast, metastatic tissues from Basal-like primary disease remain largely unchanged. In luminal disease, a significant increase in the HER2-enriched profile is observed in metastatic disease despite most tumors being clinically HER2-negative. A potential driver of the HER2-enriched profile and estrogen independence in clinically HER2-negative metastatic tissues might be FGFR4.

Citation Format: Prat A, Martínez de Dueñas E, Galván P, Garcia S, Burgués O, Paré L, Antolín S, Martinello R, Blancas I, Adamo B, Guerrero Á, Muñoz M, Nuciforo P, Vidal M, Pérez RM, Chacón JI, Caballero R, Gascón P, Carrasco E, Rojo F, Perou CM, Cortés J, Adamo V, Albanell J, Lluch A. Intrinsic subtype and gene expression changes between primary and metastatic breast cancer. [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 P6-05-02.

Abstract P4-07-04: PARP1/2 inhibition in a subset of triple negative breast cancer (TNBC) patient-derived tumor xenografts (PDX) identifies predictive biomarkers of response

Background: BRCA1/2 mutation carriers (gBRCA) have a higher risk of breast or ovarian cancer, since BRCA1/2 mutation results in impaired high-fidelity DNA repair by homologous recombination (HR) and subsequently genetic instability. In non-gBRCA TNBC, HR deficiency occurs at the somatic level, by means of BRCA1 mutation, BRCA1 epigenetic loss or mutation in other HR-associated genes. Because PARP1/2 inhibitors (PARPi) are well-tolerated and active anti-cancer agents in the advanced setting of gBRCA tumors, we sought to expand their applicability by identifying response biomarkers in TNBC.

Methods: We have assessed the antitumor response of the PARP1/2 inhibitor olaparib as single agent in a panel of 12 primary and advanced TNBC PDX models. On PDXs exhibiting primary sensitivity to olaparib, we have developed models of acquired resistance by continuous exposure to the drug and identifying progression on treatment. We have characterized the models through targeted sequencing and the analysis of the hypermethylation and expression levels of BRCA1 transcript to find potential correlates of drug-sensitivity.

Results: Three out of 12 PDXs (25%) treated with single agent olaparib, exhibit tumor regression or disease stabilization. BRCA1 is hypermethylated in two of these PARPi-sensitive TNBC PDX models and is associated with loss of BRCA1 mRNA expression. The third PARPi-sensitive TNBC PDX harbors a frameshift, heterozygous PALB2 mutation, which is no longer detected in the acquired resistance PDX model. Acquired resistance in the hypermethylated PDXs is under study as well as the duration of response compared to gBRCA PDX models.

Conclusions: Our study highlights that somatic HR-deficiency is frequent in TNBC and provides the basis of sensitivity to PARPi.

Citation Format: Serra V, Cruz C, Bruna A, Ibrahim YH, Vivancos A, Vivancos A, Nuciforo P, Bellet M, Gómez P, Pérez JM, Saura C, Vidal M, Serres X, Rueda OM, Peg V, Caldas C, O'Connor MJ, Baselga J, Cortés J. PARP1/2 inhibition in a subset of triple negative breast cancer (TNBC) patient-derived tumor xenografts (PDX) identifies predictive biomarkers of response. [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 P4-07-04.

Abstract P2-08-13: Integrating multiplex and next generation sequencing (NGS) platforms in routine molecular profiling of metastatic breast cancer (MBC) patients (pts): Trends for enrollment in genotype-directed clinical trials (GDTs)

Background/aims: Multiplex or NGS platforms increase the number of mutations (mut) detected in tumor samples respect to single-gene sequencing techniques. We aimed to assess the actionable molecular alteration (ActMA) detection rate and the enrollment in GDTs derived from the integration of these platforms in routine molecular profiling of MBC pts, in addition to FISH and IHC techniques already in use. Methods: Consecutive MBC pts screened for gene mut by Sequenom (Seq) or AmpliconSeq (ASeq) were identified. Data on FGFR1 amplification (amp), PTEN IHC, and enrollment in GDTs were collected. ActMA: any mut, PTENnull (IHC score=0), or FGFR1/HER2amp for which a matched targeted drug might be available. Targeted therapy: treatment with PI3K/mTOR, novel anti-HER2, FGFR, or AKT inhibitors (inh) irrespective of having ActMA. GDT: treatment matched to ActMA. Results: From Oct2010-Apr2015, 260 pts screened (Seq 207, ASeq 53). IHC subtype: HR+/HER2- (LUM) 65%, HER2+ 13.5%, TN 19.6%, unk 1.9%. 84 samples from a metastatic site (32.3%).

ActMA / n (%)LUMHER2+TNP value (Fisher's exact test)TotalTP53*11 (31.4)1 (50)9 (52.9)0.3421 (38.9)PIK3CA44 (26)10 (28.6)4 (7.8)0.158 (22.7)FGFR1amp21 (17.4)1 (5.3)6 (16.7)0.4728 (15.9)PTENnull12 (9.3)2 (7.7)9 (25)0.0323 (12)AKT110 (5.9)1 (2.9)-0.1511 (4.3)ERBB23 (1.8)---3 (1.2)EGFR1 (0.6)-2 (4.1)-3 (1.2)ESR1*1 (3)---1 (2)KRAS2 (1.2)---2 (0.8)Denominators vary according to platform. *Amplicon only

Proportion of PIK3CAmut was similar irrespective of the site of analysis (primary 25.5%, metastasis 21.4%; P=0.63) and platform (Seq 22.2%, ASeq 24.5%, P=0.72). ASeq detected more mutations in actionable genes than Seq (36% vs. 29%, P=0.01). At least 1 ActMA (range 0-3) was found in 53.5% of pts, with non-significant differences in HER2- subtypes (LUM 48.5% vs. TN 39.2%, P=0.32).

Subtype* / ActMA n (%)≥10123All139 (53.5)121 (46.5)111 (42.7)25 (9.6)3 (1.2)LUM82 (48.5)87 (51.5)71 (42)9 (5.3)2 (1.2)HER2+35 (100)-22 (62.9)12 (34.3)1 (28)TN20 (39.2)31 (60.8)16 (31.4)4 (7.8)-*5 pts with unk subtype not shown

Pts with ≥2 ActMA (excluding HER2amp): 11 LUM (interestingly, 3 pts with PIK3CAmut+FGFR1amp), 1 HER2+, and 4 TN. Overall, 56% of pts received ≥1 targeted therapy (range 0-4). From the 139 pts with ≥1 potential ActMA (including HER2amp if treated with a novel anti-HER2), 61.8% received a targeted therapy and 42.4% were enrolled in a GDT: PI3K/mTOR inhibitor (inh) 54 (64.3%), novel anti-HER2 16 (19.1%), FGFR inh 8 (9.5%), AKT inh 6 (7.1%). Of the 121 pts that did not have potentially ActMA, 50% received a targeted therapy. The OR for receiving targeted therapy if ActMA was present was 1.59 (95%CI 0.94-2.70, P=0.08). Conclusion: Integration of multiplex and NGS platforms in routine molecular profiling of MBC pts yields a detection rate of ActMA &gt;50%, which translates into higher probability of receiving a targeted agent and enrollment in a GDT. This suggests that physicians are pushing towards matched targeted therapies for pts that participate in molecular screening programs and have ActMA. Results on the outcome of these pts will be presented.

Citation Format: Oliveira M, Dienstmann R, Bellet M, Pérez-Garcia JM, Gómez P, Muñoz-Couselo E, Vidal M, Ortega V, Zamora E, Soberino J, Meire A, Nuciforo P, Vivancos A, Cortés J, Saura C. Integrating multiplex and next generation sequencing (NGS) platforms in routine molecular profiling of metastatic breast cancer (MBC) patients (pts): Trends for enrollment in genotype-directed clinical trials (GDTs). [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 P2-08-13.