Safety interim analysis (SIA) of atractib: A phase 2 trial of first-line (1L) atezolizumab (A) in combination with paclitaxel (P) and bevacizumab (B) in metastatic triple-negative breast cancer (mTNBC)

1084

Background: A substantial benefit from adding an immune checkpoint inhibitor to chemotherapy (CT) was reported in mTNBC patients (pts) with PD-L1+ tumors. However, many pts still have a poor outcome. ATRACTIB is exploring the synergism between A (anti-PD-L1 antibody) and B (a VEGF-targeted antibody) with P in mTNBC irrespective of PD-L1 status. We report results from protocol-specified SIA. Methods: ATRACTIB is an open-label, single-arm, phase 2 trial (NCT04408118). Pts aged ≥18 years, with unresectable locally advanced or mTNBC, ECOG performance status of 0–1, who had received no prior systemic therapy or ≥12 months since (neo)adjuvant taxane-based CT are eligible. Pts receive A (840 mg IV, days 1, 15) with P (90 mg/m2 IV, days 1, 8, 15), and B (10 mg/kg IV, days 1, 15) on each 28-day cycle until disease progression, unacceptable toxicity, or patient withdrawal. Primary endpoint is investigator-assessed progression-free survival (PFS) as per RECIST v.1.1. Secondary endpoints include objective response and clinical benefit rates, overall survival, and safety. The trial was designed to detect a treatment effect in terms of median PFS (H0: ≤7 months; H1: ≥9.5 months) and 100 pts are needed to attain 80% power at a nominal one-sided α level of 5%. One SIA was planned for evaluating safety as per CTCAE v.5.0 on the first 20 pts who had completed a 3-month follow-up or reached the end of study. Results: From Oct 5, 2020, through Nov 21, 2021, 34 pts were enrolled at 13 sites in Spain and Germany and received at least 1 dose of study treatment. Median age was 57.5 (range 40–84) years, 23 (67.6%) pts had received prior CT for early disease, and 19 (56.0%) had visceral disease. At data cutoff (Sep 30, 2021), 25 (71.4%) pts were still receiving the drug regimen. Adverse events (AEs) led to drug discontinuation in 3 (8.8%) pts. Mean relative dose intensity was 90.2% for A, 96.5% for P, and 95.7% for B. P dose reduction was reported in 7 (20.6%) pts. Five (14.7) pts required a dose delay due to AEs (11.8% for A, 11.8% for P, and 8.8% for B). The most common AEs of any grade (G) were fatigue (47.1%; 8.8% G≥3), diarrhea (38.2%; 0% G≥3), and neurotoxicity (35.3%; 8.8% G≥3). Anemia (20.6%; 0% G≥3) and neutropenia (17.6%; 8.8% G≥3) were the most frequent hematological AEs. AEs of clinical interest (AECI) for B were hypertension (17.6%; 5.9% G≥3) and pulmonary embolism (2.9%; 0% G≥3). AECI for A were pneumonitis (2.9%; 0% G≥3), autoimmune hepatitis (2.9%; 2.9% G≥3), and alanine aminotransferase increased (2.9%; 2.9% G≥3). No treatment-related deaths were reported. Conclusions: The addition of A to P and B as 1L therapy for mTNBC shows a tolerable safety profile which is consistent with known safety profile of each agent without a significant synergistic toxicity. Based on the independent data monitoring committee recommendation, patient recruitment is ongoing. Clinical trial information: NCT04408118.

SERENA-4: A phase 3 comparison of AZD9833 (camizestrant) plus palbociclib, versus anastrozole plus palbociclib, for patients with ER-positive, HER2-negative advanced breast cancer who have not previously received systemic treatment for advanced disease

TPS1101

Background: More than two thirds of patients with advanced breast cancer (ABC) have estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2−) tumors. Current standard-of-care first-line treatments include an aromatase inhibitor (AI) or fulvestrant, a selective ER degrader (SERD), combined with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. Concurrent use of luteinizing hormone-releasing hormone (LHRH) agonists is recommended for men and premenopausal women with ABC. Nevertheless, almost all ABCs eventually become resistant to endocrine therapy (ET) and the disease is incurable. New therapies are needed to combat ET resistance, maintain patient quality of life (QoL), and delay the need for chemotherapy. AZD9833 (camizestrant) is an orally bioavailable, highly potent, next-generation SERD that demonstrated anti-cancer properties across a range of preclinical models, including those with ER-activating mutations (Scott et al, 2020). A phase I study (SERENA-1) has demonstrated that AZD9833 is well tolerated and has a promising antitumor profile when administered alone or in combination with palbociclib, a CDK4/6 inhibitor (Baird et al, SABCS 2020). SERENA-4 (NCT04711252) is a randomized, multicenter, double-blind, phase III trial to evaluate the safety and efficacy of AZD9833 in combination with palbociclib for patients with ER+ HER2− ABC who have not received any systemic treatment in the advanced disease setting. Methods: SERENA-4 will enroll 1,342 patients with de novo or recurrent ER+ HER2– ABC who have not previously received systemic treatment for their locoregionally recurrent or metastatic disease. Patients with recurrent disease must have received adjuvant AI or tamoxifen therapy for at least 24 months without relapse. Patients will be randomized 1:1 to receive orally either (a) AZD9833 (75 mg, once daily), palbociclib (125 mg, once daily for 21 days followed by 7 days off treatment) and anastrozole-matching placebo (once daily) or (b) anastrozole (1 mg, once daily), palbociclib (same as active arm), and AZD9833-matching placebo (once daily). Premenopausal women and men will also receive LHRH agonists. The primary endpoint will be progression-free survival (PFS; up to 5 years). Secondary endpoints will include overall survival (up to 8 years), length of second PFS period, objective response, time to chemotherapy, and changes in QoL measures. Enrollment began in January 2021. Acknowledgments: We thank Rose Goodchild, PhD, of Oxford PharmaGenesis, UK, for providing medical writing assistance. Funding: The SERENA-4 trial is funded and overseen by AstraZeneca. Clinical trial information: NCT04711252 .

Serum phospholipids fatty acids and breast cancer risk by pathological subtype: EpiGEICAM study

e13604

Background: The role of fatty acids (FA) in breast cancer (BC) etiology is unclear. Most studies are based on self-reported dietary intake, without considering their internal transformation. This analysis tries to assess whether serum levels of 26 phospholipid FA (PL-FAs) and markers of their endogenous metabolism are associated with BC risk, both globally and by pathological BC subtype. Methods: EpiGEICAM-01 is a Spanish multicenter matched case-control study. BC cases and healthy women completed a lifestyle and a food frequency questionnaire, and serum samples were collected. Serum PL-FAs percentages were measured by gas chromatography-mass spectrometry (GC–MS). Conditional and multinomial logistic regression models were used to quantify the association of PL-FAs tertiles with BC risk, overall and by pathologic BC subtypes [luminal, HER2+ and triple negative]. Models were adjusted for age and region (multinomial models), education level, body mass index (BMI), menopausal status, age at menarche and at first birth, hormone replacement therapy, alcohol consumption, last year physical activity, history of benign breast disease, family history of BC and caloric intake, and were corrected for multiple testing. Stratified analyses by BMI and menopausal status were also performed. Results: Questionnaires and serum samples were collected from 795 case-control pairs. Women with high serum levels of stearic acid [odds ratio (OR)T3vsT1= 0.44; 95% confidence interval (CI) = 0.30-0.66], linoleic acid (ORT3vsT1= 0.66; 95% CI = 0.49-0.90) and arachidonic to dihomo-γ-linolenic acids ratio (OR T3vsT1= 0.64 95%; CI = 0.48-0.84; differences were remarkable in overweight/obese women) presented lower BC risk. Participants with high concentrations of palmitoleic acid (ORT3vsT1= 1.65; 95% CI = 1.20-2.26), trans-ruminant palmitelaidic acid (ORT3vsT1= 1.51; 95% CI = 1.12-2.02; differences observed were noticeable both in postmenopausal and in overweight/obese women), trans-industrial elaidic acid (ORT3vsT1= 1.52; 95% CI = 1.14-2.03; markedly both in premenopausal and in non-obese women), and high oleic to stearic acids ratio (ORT3vsT1= 2.04; 95% CI = 1.45-2.87) showed higher risk. These associations were similar in all BC pathological subtypes. Conclusions: Our results, which should be confirmed in future studies, emphasize the importance of analyzing fatty acids individually, as well as the desaturase activity indices. A decrease in the dietary intake of trans-monounsaturated fatty acids could be a good strategy for BC prevention.

Abstract GS2-06: Primary results of SOLTI-1402/CORALLEEN phase 2 trial of neoadjuvant ribociclib plus letrozole versus chemotherapy in PAM50 Luminal B early breast cancer: An open-label, multicenter, two-arm, randomized study

Background: Different approaches for treatment de-escalation are being investigated; however, the current ongoing phase III adjuvant trials with CDK4/6 inhibitors are not addressing the question if these drugs can replace multi-agent chemotherapy in high-risk early breast cancer. Here, we present the primary results of the CORALLEEN phase 2 trial, which evaluates the efficacy of ribociclib plus endocrine therapy (ET) as neoadjuvant treatment in patients with high-risk Luminal B disease. Methods: CORALLEEN is a parallel, multicenter, two-arm, randomized exploratory study in postmenopausal women with primary operable hormone receptor-positive (HR+)/HER2-negative breast cancer, Luminal B by Prosigna®. Other eligibility criteria include stage I-III operable breast cancer and ECOG 0-1. Patients were randomized 1:1 to receive either six 28-days cycles of ribociclib (600mg; 3-weeks-on/1-week-off) plus daily letrozole (2.5mg) or chemotherapy (CT): 4 cycles of AC (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 every 21 days) followed by weekly paclitaxel (80 mg/m2) during 12 weeks. Baseline, Day 15 on-treatment, and surgical specimens were collected for molecular characterization and evaluation of response. The primary endpoint is the rate of PAM50 Risk of Relapse (ROR)-low disease at surgery in each arm. PAM50 ROR score integrates gene expression data, tumor size, and nodal status to define a low-risk group in the adjuvant setting (i.e. >90% distant relapse-free survival at 10 years). ROR-low was defined using the standard cutpoints as <40 points if pathologically node-negative (at surgery) and <15 points if 1-3 positive nodes (at surgery). The trial was designed to estimate the rate of ROR-low disease at surgery in each arm without a formal comparison. A total of 47 evaluable patients per arm and an expected ROR-low rate of 25%, would allow a precision of the estimate between 11.5% and 12.4%. Secondary endpoints included safety, intrinsic subtype at surgery, residual cancer burden (RCB), and Preoperative Endocrine Prognostic Index (PEPI). Results: From July 2017 to November 2018, 198 patients were screened with Prosigna® across 21 sites in Spain. From these, 106 (54%) patients with Luminal B disease were recruited, and 96 (90.6%) completed treatment as planned. Main baseline patient characteristics were similar between both treatment arms: mean age 64, mean tumor size 3.8 cm, N+ 39%, mean Ki67 33.2%, and mean ROR score 72.9 (86.8% were ROR-high). A total of 101 (95.3%) surgical samples were analyzed. ROR-low rates at surgery in the ribociclib+ET and CT arms were 48% (95%CI 33.7-62.6) and 47.1% (95%CI 32.9-61.5), respectively. Intrinsic subtype conversion to Luminal A at surgery occurred in 88% of patients in the ribociclib+ET arm and in 84.3% in the CT arm. The rates of RCB0/1 and PEPI 0 in the ribociclib+ET arm were 8% (95%CI 2.2-19.2) and 24% (95%CI 13.1-38.2), respectively. The rates of RCB0/1 and PEPI 0 in the CT arm were 11.8% (95%CI 4.4-23.9) and 17.6% (95%CI 8.4-30.9). Grade 3-4 toxicities were observed in 54.9% of the patients in the ribociclib+ET arm and 69.2% in the CT arm. Additional correlative molecular analyses will be presented. Conclusions: Neoadjuvant ribociclib and letrozole in high-risk Luminal B breast cancer achieves similar rates of ROR-low disease at surgery as multi-agent chemotherapy. Future studies in high-risk early breast cancer evaluating the survival outcomes and quality of life of this combination in the absence of cytotoxic therapy are justified.

Citation Format: Joaquín Gavilá, Cristina Saura, Tomás Pascual, Cristina Hernando, Montserrat Muñoz, Laia Paré, Blanca González Farré, Pedro Fernandez, Patricia Galván, Xavier González Farré, Mafalda Oliveira, Miguel Gil Gil, Miriam Arumi, Neus Ferrer Tur, Alvaro Montaño, Yan Izarzugaza, Antonio Llombart Cussac, Raquel Bratos, Santiago González, Eduardo Martínez, Sergio Hoyos, Beatriz Rojas, Juan Antonio Virizuela, Vanesa Ortega, Rafael López, Pamela Céliz, Eva Ciruelos, Patricia Villagrasa, Aleix Prat. Primary results of SOLTI-1402/CORALLEEN phase 2 trial of neoadjuvant ribociclib plus letrozole versus chemotherapy in PAM50 Luminal B early breast cancer: An open-label, multicenter, two-arm, randomized study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr GS2-06.

Abstract CT219: Neoadjuvant letrozole and palbociclib in stage II-IIIB HR[+]/HER2[-] breast cancer with Oncotype DX Recurrence Score® (RS) 18-25 or 26-100. Analysis of RS changes at surgery (DxCARTES trial)

BACKGROUND: The combination of a CDK4/6 inhibitor (palbociclib, abemaciclib, or ribociclib) with an aromatase inhibitor (AI) significantly reduces Ki67 compared to single-agent AI in the neoadjuvant setting, but the rates of pathological complete response (pCR) or residual cancer burden (RCB) 0-I remain modest. Despite this inadequate pathological downstaging, to date, there is no data about the efficacy of this treatment in terms of molecular downstaging detected by a more refined genomic signature than Ki67, such as the Oncotype DX Breast Recurrence Score® (RS) test. The aim of this trial is to validate the ability of neoadjuvant palbociclib plus letrozole to modify two initial intermediate or high RS tumor cohorts.

TRIAL DESIGN: This is an international, multicenter, open-label, non-comparative, phase II trial. Main selection criteria include: (1) Pre- or post-menopausal women with treatment-naïve, centrally assessed, HR-positive/HER2-negative, Ki67 ≥ 20%, and stage II-IIIB breast cancer; (2) Pre-treatment RS result ≥ 18; (3) Patients agree to collect tissue samples at screening, at Cycle 1 Day 14 of treatment, and at surgery. Patients will be allocated, according to the pre-treatment RS result, either to Cohort A (RS 18-25) or Cohort B (RS 26-100) and will receive treatment with palbociclib (125 mg QD, 3/1 schedule) in combination with letrozole (2.5 mg QD, every 28-day cycle), ± LHRH analogs if pre-menopausal status, for 24 weeks. Definitive breast surgery will be performed within 7 days after completion of 6 treatment cycles. The primary objective of the study is to explore the ability of palbociclib in combination with letrozole to induce global molecular changes, measured by either the post-treatment RS result at surgery, or pCR. Secondary objectives include: (1) Concordance rate among post-treatment RS result and RCB, Ki67, and preoperative endocrine prognostic index (PEPI) score; (2) Overall response rate; (3) Safety-related outcome as per Common Terminology Criteria for Adverse Events v. 5.0. Patients will be accrued in a Simon’s two-stage design trial: optimal design in Cohort A and minimax design in Cohort B. With a unilateral type one error (alpha) set at 0.025 and a 0.8 power (type two error beta = 0.2), the required number of evaluable patients are 28. Considering a drop-out rate no lower than 10%, a sample size of 33 patients in each cohort will be needed. First Patient First Visit: Expected on April 2019.

Citation Format: Antonio Llombart Cussac, José Pérez-García, Ángel Guerrero, Begoña Bermejo, Miguel Gil, Vicente Carañana, Serafín Morales, Juan de la Haba, María Fernández, Emilio Alba, Ander Urruticoechea, Lourdes Calvo, Mireia Margeli, Antonio Antón, Manuel Ruíz Borrego, Joan Albanell, Pedro Sánchez Rovira, Meritxell Bellet, Sofia Braga, Passos Coelho, Miguel Abreu, Javier Cortés. Neoadjuvant letrozole and palbociclib in stage II-IIIB HR[+]/HER2[-] breast cancer with Oncotype DX Recurrence Score® (RS) 18-25 or 26-100. Analysis of RS changes at surgery (DxCARTES trial) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT219.

Genomic-based predictive biomarkers to anti-HER2 therapies: A combined analysis of CALGB 40601 (Alliance) and PAMELA clinical trials

571

Background: In HER2-positive breast cancer, new biomarkers of response are needed in order to direct multi-agent anti-HER2 combinations towards patients in whom they are truly needed. CALGB 40601 and PAMELA trials tested neoadjuvant dual HER2 blockade and included gene expression analysis aimed to evaluate different genomic biomarkers of trastuzumab and/or lapatinib benefit. Methods: Gene expression by mRNA sequencing (RNAseq) was performed on 265 and 142 pre-treatment tumors of the CALGB 40601 and the PAMELA clinical trials respectively. Intrinsic subtypes were determined by nCounter PAM50-predictor on the PAMELA samples. A new HER2-positive specific gene-centering method was trained on the PAMELA RNAseq data, and showed a higher concordance with PAM50 predictions obtained from nCounter platform. This method was then applied to CALGB 40601 samples. Results: In the combined cohort, the subtype distribution was 10% Luminal A, 8% Luminal B, 62% HER2-enriched (HER2-E), 10% Basal and 10% Normal-like. The pCR rate was significantly higher in HER2-E vs. not HER2-E subtypes (48.6% vs. 20.7%; P < 0.001). HER2-E subtype correlation, ERBB2 amplicon and B-cell genomic signatures were associated with pCR, while luminal signatures were associated with non-responders. In multivariate analysis HER2-E subtype, ERBB2 mRNA and IgG signature expression were independent predictors of response to paclitaxel + trastuzumab +/-lapatinib (OR = 1.98, OR = 1.51, OR = 1.48, respectively, P <0.05). The event free survival analysis at 5 years in the CALGB 40601 cohort showed a benefit of dual vs single anti-HER2-blockade (HR 0.35, P <0.05). Within the HER2-E, ERBB2-high and IgG–high subpopulations, there were also a benefit of dual vs. single anti-HER2 treatment (HR = 0.32, HR = 0.15, HR =0.15, respectively, P <0.05). Conclusions: Intrinsic subtype, ERBB2 mRNA levels, and IgG genomic signature are independent predictive biomarkers of response in the combined cohort. The clinical implementation of these biomarkers could help to design future escalation/de-escalation clinical trials in the HER2-positive neoadjuvant setting. Support: U10CA180821, U10CA180882, U24CA196171, P50-CA58223, GSK, SPORE, BCRF and SEOM. https://acknowledgments.alliancefound.org .

On-treatment changes in tumor-infiltrating lymphocytes (TIL) during neoadjuvant HER2 therapy (NAT) and clinical outcome

574

Background: Higher quantity of pretreatment TIL (PT) is associated with improved pCR and EFS in HER2+ early breast cancer (BC). The value of on-treatment TIL is unknown. Methods: The NeoALTTO trial randomized 455 women with HER2+ BC to 12 weeks NAT with trastuzumab, lapatinib or combination with paclitaxel, followed by FEC after surgery. In the PAMELA trial 151 women received 18 weeks NAT with lapatinib and trastuzumab (±hormonal therapy). TIL were quantified on PT and on-treatment (W2) biopsies using the published method on H&E slides, and tested for associations with pCR (logistic regression), EFS and OS (Cox models) in univariate (UV) and multivariate (MV) analyses. The likelihood ratio test assessed added prognostic value to clinicopathological (CP) variables. pCR associations were validated in PAMELA. We investigated enrichment of immune cell subsets using previously published RNAseq data from NeoALTTO. Results: In NeoALTTO, PT and W2 TIL were evaluable in 277/455 (61%). We defined two groups: immune-poor (L+F) and immune-enriched (II+P), see Table. Immune-enriched (41%; 134) vs poor (59%; 164) patients had significantly higher pCR rates (40% vs 21%; UV OR 2.24; 95%CI 1.31-3.85; P = .003; MV P = .009), and added significant value to CP + PT TIL for prediction of pCR (P = .003). This was further confirmed in PAMELA (N = 94/151) (26% vs 6%; UV P = .021; MV P = .028). In NeoALTTO, the immune-enriched vs poor patients had significantly improved EFS (5 yr est 85% vs 60%; UV HR 0.31; 95%CI 0.18-0.54; P < .001; MV P < .001) and OS (5 yr est 91% vs 77%; UV HR 0.40; 95%CI 0.20-0.82; P = .012; MV P = 0.026), and provided significant added prognostic value beyond CP + pCR + PT TIL (EFS P < .001) In NeoALTTO PT samples, II vs F patients had enrichment of DCs, NKs and CD8+ including tissue resident memory cells (P = .009) suggesting requirement of key immune subsets. Further validation by IHC is ongoing. Conclusions: On-treatment TIL identifies patients more likely to achieve pCR and have improved EFS in early-stage HER2+ BC, beyond CP + PT TIL. This information could aid future trial design. Clinical trial information: NCT00553358, NCT01973660. [Table: see text]

Bioluminescence Imaging to Monitor the Effects of the Hsp90 Inhibitor NVP-AUY922 on NF-κB Pathway in Endometrial Cancer

PURPOSE

In this study, we first aimed to evaluate the effects in vitro and in vivo, of the Hsp90 inhibitor NVP-AUY922, in endometrial cancer (EC). We also aimed to track nuclear factor kappa B (NF-κB) signalling, a key pathway involved in endometrial carcinogenesis and to check whether NVP-AUY922 treatment modulates it both in vitro and in vivo.

PROCEDURES

I n vitro effects of NVP-AUY922 on EC cell growth and the signalling pathways were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic assays, Western Blot and luciferase assay. NVP-AUY922 effect on Ishikawa (IK) xenograft growth was evaluated in vivo, and NF-κB activity was monitored using bioluminescence imaging.

RESULTS

NVP-AUY922 inhibited the growth of three endometrial cell lines tested in vitro. In vivo, NVP-AUY922 reduced tumour growth of 47 % (p = 0.042) compared to control condition. Moreover, the bioluminescence signal of the tumours harbouring IK NF-κB-LUC cells was significantly reduced in NVP-AUY922-treated animals compared to untreated ones.

CONCLUSIONS

NVP-AUY922 reduced EC tumour growth and NF-κB signalling both in vitro and in vivo. As therapeutic resistance of EC remains a challenge for oncologists nowadays, we think that NVP-AUY922 represents a valid alternative to conventional chemotherapy, and we believe that this approach for assessing and tracking the activation of NF-κB pathway may be of therapeutic benefit.

Activation of angiogenic pathway in the prediction of pathologic response to bevacizumab-based neoadjuvant therapy in breast cancer

10595

Background: To evaluate potential biomarkers of pathological response to bevacizumab-based neoadjuvant therapy in untreated breast cancers (BC) patients recruited in a phase II, multicenter clinical trial. Methods: Patients received a single infusion of bevacizumab (15 mg/ kg) (C1) 3 weeks prior to the beginning of neoadjuvant chemotherapy (NAC) consisting in 4 cycles of docetaxel (60 mg/mq), doxorubicin (50 mg/mq) and bevacizumab (15 mg/ kg) every 21 days (C2-C5) following by surgery. Biomarker expression was assessed by immunohistochemistry (Ki67, CD31, CD31/Ki67, VEGFR2, pVEGFR2 [Y951]) before and after bevacizumab infusion (C1). Gene expression was analyzed using Affimetrix Human Gene ST 1.0. Results: This analysis was performed on 73 patients (49 yr, range 29-70). Twenty (27%) patients obtained best response (G4-G5) whether 50 (68%) were considered as no responder (G1-G2-G3). Response was associated with negative estrogen receptors expression (p=0.02) and high Ki67 basal and after C1 expression (p=0.009 and p=0.01). Six (54%) of the triple negative tumors were responders (p=0.05). Interestingly, change in pVEGFR2 [Y951] staining induced by bevacizumab administration was found significantly associated with response (p=0.0). Decrease in the phosphorilation status of VEGFR2 (Y951) >70% yielded a receiver operating characteristic (ROC) curve area of 0.681 (95% CI: 0.536 - 0.825) with 84% sensitivity and 95% specificity. The positive and negative predictive values for this marker were 60% and 64%, respectively. The change in phosphorilation status of VEGFR2p remains a significant predictor biomarker of response in multivariate analysis (OR=0.9, IC%95 0.96-0.99, p=0.04) after adjusting for clinical-pathological characteristics. Conclusions: These findings suggest the role of the phosphorilation status of VEGFR2 as predictive biomarkers of pathological response to bevacizumab in neoadjuvant setting in breast cancer.

Efficacy and safety of weekly oral vinorelbine (NVBO) as single agent in first- or second-line metastatic breast cancer (MBC)

e11545

Background: NVBO has shown high activity and good safety profile when given as single agent chemotherapy (CT) for MBC. Oral CT formulations allow maintenance of quality of live and minimal interference with a normal lifestyle. Methods: Main inclusion criteria for this retrospective study were: Histologically or citologically confirmed MBC, no more than 1 prior CT line for MBC; prior (neo)adjuvant CT, hormonetherapy or radiotherapy allowed; adequate bone marrow, kidney and liver function. The study protocol was approved by an ethics committee. Data was collected from patients (p) treated between Apr/2006 and Dec/2010 with NVBO 60 mg/m2 weekly until progression or unacceptable toxicity. 70 patients fulfilled the inclusion criteria. Patient’s characteristics were: Median age, 65 years (range 38-82); >75 years old, 20%; ECOG PS 0-1 in 91% p and PS 2 in 9%; ER+ &/or PR+, 41 p (59%); >2 metastatic sites in 61%; prior (neo)adjuvant CT in 48 p (69%); prior hormonotherapy, 44 p (63%). Measurable disease in 68 p (97%). 1 p received trastuzumab concomitantly. Results: Median number of administrations (a) 11 (range 2-36). 1st/2nd line: 41%/59%. We analyzed 923 a. Dose delayed or reduced due to hematological toxicity in 2.7% a, related non-hematological toxicity in 0.3% a. Dose was reduced in 1% a. Hematological toxicities (%a): neutropenia grade (g) 3, 0.8%; febrile neutropenia 1 p who died due to septic shock after 9 a. Non-hematological toxicities (%a): pain g 3-4, 0.5%; constipation g 3-4, 0.3%; ileus paraliticus g 3, 0.1%; infection g 3, 0.1%; nausea/vomiting g4, 0.1% . 68 p were evaluable for response. 1 CR (1.5%), 19 PR (27.9%) and 16 SD (23.5%) were reported. Objective response (OR) rate 29.4% [CI 95%: 19%-41.7%]. Median progression free survival 4 m [CI 95%, 2.3-5.8]. Median survival has not been reached at the time of analysis. Conclusions: Our findings confirm the consistently produced clinically meaningful efficacy of single agent NVBO for MBC. We observed a favorable safety profile with a particular low incidence of myelosupression and alopecia. We consider that oral vinorelbine is a suitable 1st or 2nd-line treatment for convenient administration in an outpatient environment in selected p with MBC.

Dynamic contrast-enhanced MRI versus 18F-misonidazol-PET/CT to predict pathologic response in bevacizumab-based neoadjuvant therapy in breast cancer

10512

Background: To investigate the role of DCE-MRI versus 18F-Misonidazole (FMISO) positron emission tomography (PET/CT) in the prediction of pathological response to bevacizumab-based neodajuvant therapy. Methods: 73 chemotherapy naïve, stage II and III breast cancer (BC) patients (pts) were enrolled in a phase II, single-arm, multicenter, open-label and prospective clinical trial. Pts received single infusion of bevacizumab (15 mg/ kg) (C1) 3 weeks prior to the beginning of neoadjuvant chemotherapy (NAC) consisting of 4 cycles of docetaxel (60 mg/mq), doxorubicin (50 mg/mq) and bevacizumab (15 mg/ kg) every 21 days (C2-C5), followed by surgery. Tumor proliferation, hypoxia and perfusion were evaluated respectively using 18F-Fluorothymidine (FLT) and 18F-Misonidazole (FMISO) positron emission tomography (PET/CT) and dynamic contrast enhancement magnetic resonance (DCE-MR). Serial imaging studies were performed in parallel at several time points including baseline (BL) and 14-21 days after bevacizumab alone (C1). Results: After only one administration of bev, tumor proliferation and perfusion assessed using FLT-PET and DCE-MRI significantly decrease (-26% and -46%, p<0.001) but these changes were not found to be associated with final response. Most important, changes in tumor hypoxia induced by bevacizumab was significantly associated with pathological response (p= 0.004) and was an independent predictor of response in multivariate analysis (RR=0.95, IC 95% 0.92-0.99, p=0.02). Decrease in FMISO uptake >10% yielded a ROC curve area of 0.7 (95% CI: 0.56 - 0.85) with high specificity (94%). Conclusions: Our findings suggest a significant value of early changes in tumor hypoxia assessed by FMISO-PET as a biomarker of pathological response in bevacizumab-based neoadjuvant therapy in breast cancer.

Phase III Trial Evaluating the Addition of Paclitaxel to Doxorubicin Followed by Cyclophosphamide, Methotrexate, and Fluorouracil, As Adjuvant or Primary Systemic Therapy: European Cooperative Trial in Operable Breast Cancer

Purpose

To evaluate the addition of paclitaxel to an anthracycline-based adjuvant regimen and to compare this combination with the same regimen given as primary systemic (neoadjuvant) therapy.

Patients and Methods

A total of 1,355 women with operable breast cancer were randomly assigned to one of three treatments: surgery followed by adjuvant doxorubicin (75 mg/m2) followed by cyclophosphamide, methotrexate, and fluorouracil (CMF; arm A); surgery followed by adjuvant paclitaxel (200 mg/m2) plus doxorubicin (60 mg/m2), followed by CMF (arm B); or paclitaxel (200 mg/m2) plus doxorubicin (60 mg/m2) followed by CMF followed by surgery (arm C). The two coprimary objectives were to assess the effects on relapse-free survival (RFS) of the addition of paclitaxel to postoperative chemotherapy (arm B v arm A) and primary chemotherapy versus adjuvant chemotherapy (arm B v arm C).

Results

Doxorubicin plus paclitaxel followed by CMF was well-tolerated as adjuvant or as primary chemotherapy. The addition of paclitaxel to adjuvant doxorubicin followed by CMF significantly improved RFS compared with adjuvant doxorubicin alone followed by CMF (hazard ratio [HR], 0.73; P = .03). Distant RFS was similarly improved (HR, 0.70; P = .027). There was no significant difference in RFS when the paclitaxel/doxorubicin/CMF chemotherapy was given before surgery compared with the same regimen given after surgery (HR, 1.21; P = .18). However, the rate of breast-conserving surgery was significantly higher with preoperative chemotherapy (63% v 34%; P < .001).

Conclusion

Incorporating paclitaxel into anthracycline-based adjuvant therapy resulted in a significant improvement in RFS and distant RFS. When given as primary systemic therapy, the paclitaxel-containing regimen allowed breast-sparing surgery in a significant percentage of patients.

Relationship between quantitative estrogen and progesterone receptor expression and human epidermal growth factor receptor 2 (HER-2) status with recurrence in the Arimidex, Tamoxifen, Alone or in Combination trial

PURPOSE

To determine the relationship between quantitative estrogen-receptor (ER) and progesterone-receptor (PgR) expression and human epidermal growth factor 2 (HER-2) status with time to recurrence (TTR) in postmenopausal women with hormone receptor-positive primary breast cancer treated with anastrozole or tamoxifen as adjuvant therapy.

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded tumor blocks were retrospectively collected from patients in the monotherapy arms of the Arimidex, Tamoxifen Alone or in Combination (ATAC) trial and centrally tested for ER, PgR and HER-2. ER and PgR were scored using continuous scales and HER-2 was scored as 0 to 3+ with 2+ cases being analyzed by fluorescence in situ hybridization.

RESULTS

Blocks were collected from 2,006 of 5,880 eligible patients. Tissue was assessable and ER and/or PgR positivity confirmed centrally in 1,782 cases. In these, TTR was longer for anastrozole than for tamoxifen by a similar extent to that in the overall trial. None of the three biomarkers identified a set of patients with differential benefit from anastrozole over tamoxifen. Patients with low ER, low PgR, and high HER-2 expression had a poorer prognosis with either drug. Only 2.6% of patients in the highest quartile of PgR experienced recurrence after 5 years, compared with 13.2% in the lowest quartile.

CONCLUSION

Quantitative expression of ER and PgR and HER-2 status did not identify patients with differential relative benefit from anastrozole over tamoxifen: TTR was longer for anastrozole than for tamoxifen in all molecular subgroups. Low ER or PgR or high HER-2 expression are associated with a high risk of recurrence with either anastrozole or tamoxifen.

Feasibility and tolerability of sequential doxorubicin/paclitaxel followed by cyclophosphamide, methotrexate, and fluorouracil and its effects on tumor response as preoperative therapy

PURPOSE

The European Cooperative Trial in Operable breast cancer (ECTO) randomly tested whether efficacy of adjuvant doxorubicin followed by i.v. cyclophosphamide, methotrexate, and fluorouracil (CMF; doxorubicin-->CMF, arm A) could be improved by adding paclitaxel (doxorubicin/paclitaxel-->CMF) as adjuvant (arm B) or primary systemic therapy (PST, arm C). We report here feasibility, tolerability, locoregional antitumor activity, and breast conservation rate.

METHODS

A total of 1,355 women entered the study. Feasibility and safety were compared in arm A versus arms B plus C. Surgical findings were compared in arms A plus B versus arm C.

RESULTS

Grade 3 or 4 National Cancer Institute toxicities were low (<5%) in all arms. Neuropathy was more frequent in the paclitaxel-containing arms (grade 2, 20.5% versus 5.0%; grade 3, 1.3% versus 0.2%). At 31 months of follow-up, asymptomatic drop of left ventricular ejection fraction was similar in all arms, whereas symptomatic cardiotoxicity was recorded in three patients (0.5%) in A and in three patients (0.3%) in B plus C. PST induced clinical complete plus partial remission in 78%, with an in-breast pathologic complete response rate of 23% and an in-breast plus axilla pathologic complete response rate of 20%. In the multivariate analysis, only estrogen receptor (ER) status was significantly associated with pathologic complete response (odds ratio for ER negative, 5.77; 95% confidence interval, 3.49-9.52; P<0.0001). PTS induced a significant axillary downstaging (P<0.001), and breast sparing surgery was feasible in 65% versus 34% (P<0.001).

CONCLUSIONS

Doxorubicin/paclitaxel-->CMF is feasible, safe, and well tolerated. Given as PST, it is markedly active, allowing for breast-sparing surgery in a large fraction of patients.