Final results from a phase III randomized clinical trial of adjuvant endocrine therapy ± chemotherapy in women ≥ 70 years old with ER+ HER2- breast cancer and a high genomic grade index: The Unicancer ASTER 70s trial

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Background: Benefit of adjuvant chemotherapy (CT) in addition to endocrine therapy (ET) remains controversial for patients (pts) aged ≥ 70 years with oestrogen receptors-positive (ER+) HER2-negative (HER2-) breast cancer (BC). In a large prospective trial, we first assessed the tumour genomic grade index (GGI) in all pts, and second, randomized pts with a high GGI between CT + ET vs. ET alone. Methods: Eligible pts were women ≥ 70 years with ER+ HER2- primary BC or isolated local relapse, irrespective of other characteristics, for whom adjuvant systemic treatment was considered. G8 score, Charlson comorbidity index (CCI) and 4-year mortality Lee score were collected at baseline. GGI was centrally performed by RT-PCR on FFPE samples. Pts with low GGI were not recommended to receive CT and were followed in an observational cohort. Pts with high (+ equivocal) GGI were randomized 1:1 to CT + ET vs. ET alone, using G8, pN and centre for stratification. Investigators chose between 3 CT regimens: 4 cycles of doxorubicin/cyclophosphamide, non-pegylated liposomal doxorubicin/cyclophosphamide or docetaxel/cyclophosphamide, given q3w with G-CSF. Standard ET consisted of 5 years of aromatase inhibitor, tamoxifen or a sequence based on tolerance. Based on CALGB 49907 results, the primary objective was to demonstrate an overall survival (OS) benefit for CT (4-year assumptions 87.5 vs 80%, HR=0.60) in the intent to treat (ITT) population. With 171 events, the trial had 90% power to demonstrate a difference with a bilateral test α=0.05. Secondary objectives included BC specific survival (BCSS), invasive disease-free survival (iDFS), event-free survival (EFS), competing events, cost-effectiveness and Q-TWiST analysis, geriatric dimensions, willingness and quality of life. Results: Between 04/2012 and 05/2016, 1,969 pts from 61 French and 12 Belgian centres were enrolled. Of them, 1,089 (55%) were randomized between CT + ET and ET alone. Median follow-up was 5.8 years at the data cut-off (17/12/2021) with 180 OS events observed. Median age was 75 (70-92), G8 score, CCI and Lee score being >14, ≤ 2, and ≤ 8 in 60%, 62% and 84% of pts, respectively. Tumours were ≥ pT2, pN+, isolated local relapses, with histological grade III, in 56%, 46%, 11% and 39% of cases, respectively. No significant OS difference was observed between arms (HR 0.85 [0.64-1.13], p=0.2538); 4-year OS was 90.5% in the CT + ET arm and 89.7% in the ET alone arm. The forest plot could not identify any subgroup deriving significant benefit from CT. ITT and per protocol analysis of secondary objectives (BCSS, iDFS, EFS) showed similar results. Conclusions: In this large phase III trial, we did not find a statistically significant OS benefit with the addition of CT to ET after surgery for ER+ HER2- BC with a high GGI. Analysis of the other outcome measures will be presented. Clinical trial information: NCT0156405.

Real-life data of antiandrogens (AA) use in metastatic androgen receptor positive triple negative breast cancer (AR+ TNBC): The ATOVAT retrospective French cohort

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Background: AR+ TNBC account for around 25% of all TNBC. Identification of those patients is difficult since AR expression (IHC) testing is not routinely recommended. Published data of 3 trials using different antiandrogens (AA) found clinical benefit rates (CBR) at 6 months ranging from 19 to 29% with excellent toxicity profiles. The aim of this retrospective trial was to assess the clinical benefit of AA in real life. Methods: Patients with metastatic AR+ (IHC staining > 10% assessed by local laboratories) TNBC treated with an antiandrogen in metastatic setting were eligible. Patients should have received at least one dose of the following AA: abiraterone acetate, enzalutamide or bicalutamide. Antiandrogens had to be given after documented progression and must not be carried out as part of a clinical trial. Patients could be chemotherapy naïve for their metastatic disease or have received any number of previous line. 30 oncology centers involved in clinical research in France were screened by questionnaire and data were collected in each patient files. The aim was to describe the 6-months CBR and safety in real-life patients. Assessable patients received at least 4 weeks of AA and present at least one disease assessment. Results: 26 patients from 5 French sites were deemed eligible and 24 patients were assessable. Treatment were conducted between January 2002 and January 2021. Median age at initiation of AA was 70 years (range 50-90). 50 % (N = 13) presented liver and/or lung mets and 27% (N = 7) non progressing and non-symptomatic cerebral mets. Median number of previous line of chemotherapy was 3 (range 0-10). AA used were: abiraterone acetate (62%), enzalutamide (8%) and bicalutamide (30%). Median time from mets diagnosis to AA treatment initiation was 18 months (range 0-168). 6-months CBR were 29% (N = 7) with 5 objective responses (2 CR, 3 PR) and 2 SD. 4-months CBR were 33% (N = 8). PFS and OS were 3.2 months (0.8- 36.1) and 9.5 (1.3-63.8) months, respectively. 2 pts further received second line AA with 1 with SD as a best response. 57% (4/7) of patients presenting 6-months clinical benefit received AA in first line versus 18% (3/17).There were no grade 3 or more side effects reported. Conclusions: Real-life data of antiandrogens use in metastatic AR+ TNBC are in line with data from published clinical trials using the same drugs. There were no new safety signal in this retrospective cohort supporting the use of antiandrogens in AR+ (> 10%) TNBC in the absence of other therapeutic opportunity or available clinical trials.

Subgroup of post-neoadjuvant luminal-B tumors assessed by HTG in PENELOPE-B investigating palbociclib in high risk HER2-/HR+ breast cancer with residual disease

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Background: About one third of patients with hormone-receptor-positive (HR+), HER2‐ primary breast cancer with residual invasive disease after neoadjuvant chemotherapy will relapse despite adjuvant endocrine therapy. Therapeutic inhibition of cyclin-dependent kinase 4 and 6 (CDK 4/6) by palbociclib combined with endocrine therapy demonstrated highly relevant efficacy in metastatic breast cancer. The phase III PENELOPE-B (NCT01864746) study did not show a significant benefit from palbociclib in women with centrally confirmed HR+, HER2- primary breast cancer without a pathological complete response after taxane‐containing neoadjuvant chemotherapy and at high-risk of relapse (CPS‐EG score ≥3 or 2 and ypN+) for the primary endpoint (Loibl et al. JCO 2021). Methods: After completion of neoadjuvant chemotherapy and locoregional therapy, PENELOPE-B patients were randomized (1:1) to receive 13 cycles (1 year) of palbociclib 125mg daily or placebo on days 1-21 in a 28d cycle in addition to standard endocrine therapy. Analysis of the primary endpoint of invasive disease-free survival (iDFS) was planned after 290 events. Secondary objective included iDFS in luminal-B group by treatment. Gene expression in post-neoadjuvant surgical residual tumor tissue samples was profiled using the HTG EdgeSeq Oncology Biomarker Panel targeting 2559 genes (HTG Molecular Diagnostics Inc.). Based on 91 genes of this panel the AIMS subtype (Paquet & Hallett, JNCI 2014) was calculated. Results: Gene expressions were measured in tumors from 906 of 1250 (72%) PENELOPE-B patients; 663 had LumA subtype, 64 LumB, 135 NormL, 16 BasalL, and 28 HER2E. Compared to LumA the LumB patients were older, had higher post-neoadjuvant Ki-67, higher risk status (CPS-EG), and higher grade; no significant correlation was found for the region of participating sites, cT, ypT, and ypN. Patients with LumB tumors had an estimated 3-year iDFS of 71.9% with palbociclib vs 44.8% with placebo HR = 0.50 (0.24-1.05); outcome was similar in patients with LumA tumors (3-year iDFS 83.9% vs 79.5%, HR = 0.93 (0.68-1.28), interaction p = 0.132); this was confirmed in multivariable analyses. Ki-67 by IHC and proliferation biomarkers from the HTG panel also showed no significant interaction with treatment. Conclusions: PENELOPE-B did not show a benefit from the addition of 1 year palbociclib to endocrine therapy compared to placebo in the total enrolled high-risk primary breast cancer population. However, the small group of luminal-B tumors (n = 64) derived benefit from palbociclib, although without a statistically significant interaction. Further investigation is required in a larger cohort to validate a palbociclib benefit that might be confined to this group.

Palbociclib combined with endocrine treatment in breast cancer patients with high relapse risk after neoadjuvant chemotherapy: Subgroup analyses of premenopausal patients in PENELOPE-B

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Background: PENELOPE-B assessed efficacy of the CDK4/6 inhibitor 1-year palbociclib versus placebo added to endocrine therapy (ET) as post-neoadjuvant treatment in a high-risk breast cancer population. Palbociclib did not improve invasive disease-free survival (iDFS) compared to placebo (3-year iDFS 81.3% vs 77.7%) (Loibl et al. J Clin Oncol 2021). Here we report results from the subpopulation of premenopausal women. Methods: Patients with hormone receptor positive, HER2-negative breast cancer without pathological complete response after taxane‐containing neoadjuvant chemotherapy and at high risk of relapse (CPS‐EG score ≥3 or 2 and ypN+) were randomized (1:1) to receive 13 cycles of palbociclib 125mg daily or placebo on days 1-21 in a 28d cycle in addition to standard endocrine treatment including tamoxifen (TAM) +/- gonadotropin-releasing hormone analogue (GnRH) and aromatase inhibitor (AI) +/- GnRH. Randomization was stratified by nodal status at surgery, age ( < 50 vs ≥50 years), Ki-67, region, and CPS-EG score. Results: 616/1250 patients were premenopausal at the time of enrollment, 185 of these patients (30.0%) were younger than 40 years of age. 95.2% had ypN+ after surgery; 42.8% had ypT2 and 46.8% a CPS-EG score of 3. 23.1% of the premenopausal women had a Ki67 of > 15% in residual disease. 66.1% started with TAM alone; 19.3% with TAM and ovarian function suppression (OFS); and 13.6% received an AI+OFS. There was no difference in iDFS between palbociclib and placebo in the premenopausal women HR 0.948 (0.693-1.30). The 3-year iDFS was 80.6% and 78.3%, respectively. Palbociclib vs placebo in subgroups by endocrine treatment: TAM alone HR 1.05 (0.715-1.53) p = 0.817; TAM+GnRH HR 0.52 (0.267-1.02) p = 0.057 and AI+GnRH HR 1.58 (0.548-4.56) p = 0.397; pinteraction0.124. Hematologic toxicity was significantly more common with palbociclib. Non-hematological toxicity any grade palbociclib vs placebo were: fatigue 67.4% vs 51.3%; hot flushes 52.2% vs 54.8%; bone pain 15.6% vs 16.6%; and vaginal dryness 11.0% vs 11.5%. When receiving palbociclib fewer patients in the AI+GnRH group vs the TAM +/- GnRH cohort experienced anemia (54.1% vs 80.5%) and thrombocytopenia (37.8% vs 65.1%). Fatigue (75.7% vs 66.3%) and nausea (40.5% vs 24.9%) were more common with AI+GnRH than TAM +/-GnRH when palbociclib was added. Thromboembolic events were low with overall 9 events (4 vs 5; AI+GnRH 2.4% vs 1.3% TAM+/-GnRH). Conclusions: The addition of palbociclib to endocrine therapy did not improve iDFS in premenopausal women. These are the first safety results from a phase III study for the combination tamoxifen +/-GnRH and palbociclib. The addition of palbociclib to tamoxifen +/-GnRH in premenopausal women did not increase side effects compared to AI+GnRH and seems to be an alternative to AI+GnRH. Clinical trial information: NCT01864746.

Primary analysis of KAITLIN: A phase III study of trastuzumab emtansine (T-DM1) + pertuzumab versus trastuzumab + pertuzumab + taxane, after anthracyclines as adjuvant therapy for high-risk HER2-positive early breast cancer (EBC)

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Background: The standard of care for HER2-positive EBC is chemotherapy plus one year of HER2-directed therapy. However, recurrence—particularly in high-risk populations—remains a problem, as does systemic chemotherapy-associated toxicity. In KAITLIN, we aimed to improve efficacy and reduce toxicity by replacing taxanes and trastuzumab with T-DM1. Methods: KAITLIN (NCT01966471) is a phase 3, randomized, open-label study that enrolled 1846 patients with adequately excised, centrally confirmed HER2-positive EBC either node-positive (LN+); or node-negative, HR-negative, and tumor size > 2.0 cm. Within 9 weeks of surgery, patients were randomized 1:1 to 3-4 cycles of anthracycline-based chemotherapy followed by 18 cycles of T-DM1 3.6 mg/kg + pertuzumab 420 mg q3w (loading dose [LD] 840 mg) (AC-KP) or taxane (3-4 cycles) + concurrent trastuzumab 6 mg/kg (LD 8 mg/kg) + pertuzumab 420 mg q3w (LD 840 mg) (AC-THP). Patients were stratified by world region, nodal status, HR status, and anthracycline type. Adjuvant radiotherapy and/or endocrine therapy was administered after 4 cycles of HER2-targeted therapy when indicated. The co-primary endpoints were invasive disease-free survival (IDFS) in the LN+ and in the ITT populations applying a hierarchical testing procedure. Secondary endpoints included overall survival (OS), patient-reported outcomes (PROs), and safety. Results: KAITLIN did not meet its co-primary endpoints. In LN+ patients (n = 1658), there was no significant difference between arms in IDFS event risk (stratified hazard ratio = 0.97; 95%CI 0.71–1.32). Three-year IDFS was 94.1% with AC-THP and 92.7% with AC-KP. Results were similar in the ITT population (stratified hazard ratio = 0.98; 95%CI 0.72–1.32; 3-year IDFS: 94.2% vs 93.1%). OS data are immature with an event rate of ~4%–5% in each arm. During the study overall, there was a similar incidence of grade ≥3 AEs (55.4% vs 51.8%) and SAEs (23.3% vs 21.4%) with AC-THP and AC-KP, respectively. More patients receiving AC-KP than AC-THP discontinued T-DM1 or trastuzumab, respectively, because of AEs (26.8% vs 4.0%). PRO data will be presented. Conclusions: Replacing adjuvant taxane and trastuzumab with T-DM1 did not result in significantly improved efficacy or overall safety. Nonetheless, in this high-risk population, a favorable IDFS outcome was achieved in both study arms. HP + chemotherapy remains the standard of care for patients with high-risk HER2-positive EBC. Clinical trial information: NCT01966471 .

Patient-reported outcomes (PROs) from KATHERINE: A phase III study of adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab (H) in patients (pts) with residual invasive disease after neoadjuvant therapy for HER2-positive breast cancer

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Background: The phase 3 KATHERINE (NCT01772472) study, met its primary endpoint by demonstrating significantly improved invasive disease-free survival with adjuvant T-DM1 compared to H in pts with residual invasive disease after neoadjuvant chemotherapy plus HER2-targeted therapy. PROs are reported here. Methods: Eligible pts had HER2-positive early breast cancer, received taxane- and H-containing neoadjuvant therapy (with/without anthracyclines) followed by surgery, and had residual invasive disease in the breast and/or axillary nodes. Pts were randomized to 14 cycles of adjuvant T-DM1 (3.6 mg/kg IV q3w) or H (6 mg/kg IV q3w) and adjuvant endocrine and radiation therapy per standard of care. The EORTC Quality of Life Questionnaire–Core 30 (QLQ-C30) and QLQ–Breast Cancer (QLQ-BR23) were completed at screening, at day 1 of cycles 5 and 11, within 30 days after study drug completion, and at 6 and 12 months’ follow-up. Results: Of 1,486 pts randomized (T-DM1, n = 743; H, n = 743), 612 (82%) and 640 (86%), respectively, had valid baseline and ≥1 post-baseline PRO assessments. During the study, pts in both arms had similar mean scores on the QLQ-C30 and QLQ-BR23 function and symptom scales. There was no clinically meaningful change (≥10 points) from baseline in the mean scores in either arm, including on symptoms similar to AEs seen with T-DM1 (eg, fatigue). While more pts in the T-DM1 arm reported clinically meaningful deterioration in role functioning (49% vs 41%), appetite loss (38% vs 28%), constipation (47% vs 38%), fatigue (66% vs 61%), nausea/vomiting (39% vs. 30%), and systemic therapy side effects (49% vs 36%) at ≥1 assessment, the proportion reporting clinically meaningful change in functioning was similar between arms at any given assessment. Conclusions: Mean scores showed only small deterioration from baseline in patient-reported treatment-related symptoms in both study arms. While more pts in the T-DM1 arm reported deterioration at some point in several symptoms, baseline global health status and functioning were generally maintained in both arms over the treatment course. Clinical trial information: NCT01772472.

Abstract GS4-03: Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Update of the SOFT trial

Background: The primary results of SOFT at 5.6 years median follow-up found adding OFS to T did not provide a significant benefit in the overall study population of premenopausal women with HR+ BC (Francis et al, NEJM 2015). For those women at sufficient risk for recurrence to warrant adjuvant chemotherapy (CT) and who remained premenopausal, the addition of OFS improved disease outcomes. Follow-up was immature for overall survival (OS). We report a planned update with visit cut-off of 31Dec16 after 8 yrs median follow-up.

Methods: SOFT randomized premenopausal women with HR+ BC from Nov 2003 to Jan 2011 to 5 yrs of T vs T+OFS vs Exemestane(E)+OFS. OFS was by choice of GnRH agonist triptorelin, oophorectomy or ovarian irradiation. SOFT was stratified by the use of prior CT; 47% received no CT and 53% remained premenopausal after prior CT, determined by premenopausal estradiol level within 8 months of CT completion. The primary endpoint was invasive disease-free survival (DFS; randomization until invasive local, regional, distant recurrence or contralateral breast; invasive second malignancy; death). Secondary endpoints included invasive breast cancer-free interval (BCFI), distant recurrence-free interval (DRFI) and OS. NCT00066690.

Results: DFS for patients assigned T+OFS (n=1015) was significantly improved over T (n=1018; HR=0.76 [95%CI 0.62-0.93]) and 8yr DFS was 83.2% vs 78.9%, respectively; BCFI and DRFI results were supportive (see Table). Hazard ratios for these 3 endpoints showed no heterogeneity by use of prior CT. For patients with prior CT, 8yr DFS was 76.7% with T+OFS vs 71.4% with T (Δ=5.3%); in those without CT, 8yr DFS was 90.6% vs 87.4% (Δ=3.2%). E+OFS (n=1014) improved outcomes relative to T (Table); 8yr DFS for E+OFS was 85.9% (80.4% with use of prior CT and 92.5% for those without CT). OS was improved with T+OFS vs T (8yr OS 93.3% vs 91.5%). 8yr OS was 92.1% with E+OFS. 201/225 deaths occurred in women with prior CT. For women without CT there have been 10, 5 and 9 deaths in the T+OFS, T and E+OFS groups (total n=1419), respectively, only half of these deaths after breast cancer event.

N. EventsHazard Ratio (95% CI)Endpoint(3 arms)T+OFS vs TE+OFS vs TDFS5180.76 (0.62-0.93) P=0.0090.65 (0.53-0.81)BCFI4370.76 (0.61-0.95)0.64 (0.51-0.81)DRFI3060.86 (0.66-1.13)0.73 (0.55-0.96)OS2250.67 (0.48-0.92)0.85 (0.62-1.15)

Overall toxicity was worse with T+ OFS than with T, including 32% vs 25% grade 3+ targeted AEs. Early cessation of tamoxifen occurred for 19% assigned T+OFS and 22% of women assigned T; the cumulative incidence of early cessation of triptorelin on the T+OFS arm was 23% by 4yrs. Early cessation of exemestane occurred for 28% and of triptorelin for 21% by 4yrs on the E+OFS arm.

Conclusions: With additional follow-up to a median of 8yrs, SOFT further supports the value of OFS for some premenopausal women. Follow-up continues, which will further clarify the safety and the benefit of OFS for late recurrence and overall survival. Oncologists appear to be able to select a low risk group (no chemotherapy) for whom treatment escalation is unlikely to improve survival.

Citation Format: Fleming G, Francis PA, Láng I, Ciruelos EM, Bellet M, Bonnefoi HR, Climent MA, Pavesi L, Burstein HJ, Martino S, Davidson NE, Geyer Jr CE, Walley BA, Coleman RE, Kerbrat P, Buchholz S, Ingle JN, Rabaglio-Poretti M, Colleoni M, Regan MM. Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Update of the SOFT trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS4-03.

A gene signature of chemo-immunization to predict outcome in patients with triple negative breast cancer treated with neoadjuvant chemotherapy

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Background: In patients with triple-negative breast cancer (TNBC), the extent of tumor-infiltrating lymphocytes (TILs) in the residual disease after anthracycline-based neoadjuvant chemotherapy (NACT) is associated with a better prognosis. We aimed to develop a genomic signature from pre-treatment samples to predict the extent of TILs after NACT, and then to test its prognostic value on survival. Methods: Using 99 pre-treatment samples (training set), we generated a four-gene signature that predicts post-NACT TILs using the LASSO technique. Prognostic value of the signature on survival was assessed on the training set (n=99) and then evaluated on an independent validation set including 185 patients with TNBC treated with NACT. Results: A four-gene signature, assessed on pre-treatment samples and combining the expression levels of HLF, CXCL13, SULT1E1, and GBP1 predicted the extent of lymphocytic infiltration after NACT. In a multivariate analysis performed on the training set, a one-unit increase in the signature value was associated with distant-relapse free survival (DRFS) (HR: 0.28, 95%CI: 0.13-0.63, p=0.002). For the validation set, the four-gene signature was significantly associated with DRFS in the entire set (HR: 0.26, 95%CI: 0.11-0.59, p=0.001) and in the subset of patients with residual disease (HR: 0.23, 95%CI: 0.10-0.55, p< 0·001). Conclusions: We developed a four-gene signature of chemotherapy-induced immune-activation, which predicts outcome in patients with TNBC treated with NACT. [Table: see text]

Locoregional recurrence (LRR) after neoadjuvant chemotherapy (NAC): Pooled-analysis results from the Collaborative Trials in Neoadjuvant Breast Cancer (CTNeoBC)

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Background: There is limited information on LRR rates in pts treated with NAC. Methods: 12 large NAC BC trials (11,955 pts) with pCR information and long-term F/U for LRR, EFS and OS were included. Primary aims were to assess LRR rates by pCR, tumor subtype, surgery type and other clinico-pathologic factors. Main definition of pCR was ypT0/is ypN0. Results: Median F/U: 5.4 years. Median age: 49, T2 tumors: 61%, Inflammatory BC: 4%; Clinically(+) nodes: 47%. Overall LRR: 6.8% (95% CI: 6.3, 7.2). LRR was 5.5% with pCR (ypT0/isypN0) vs. 7.1% without. After lumpectomy, LRR rates were similar with pCR (6.0%) vs. without (6.3%). After mastectomy, LRR rates were lower with pCR (3.8%) vs. without (8.1%), irrespective of XRT use. In HR(+)/HER2(-) BC, LRR rates were low with pCR (1.9%) or without (3.3%) with similarly low LRR rates in grade 1/2 tumors (pCR: 2%, no-pCR: 2.6%). In HR(+)/HER2(-)/grade 3 BC LRR rates were lower with pCR (1%) vs. without (5.3%). In HER2(+) BC LRR rates were similar with pCR (5.1%) or without (7.3%), mainly seen in HER2(+)/HR(+) BC (5.7% vs. 5.5%). In contrast, in HER2(+)/HR(-) BC LRR rates were lower with pCR (4.9%) vs. without (9.8%). Also, in HR(-) /HER2(-) BC LRR rates were lower with pCR (4.9%) vs. without (8.6%). LRR varied with path nodal status and TNM stage at surgery: node(-): 5.6% vs. node(+) 8.9%; stage 0: 5.3%; stage 1: 5.2%; stage 2: 7.3%; stage 3: 10.1%. Conclusions: LRR rates after NAC are low and vary by pCR status, tumor subtype, type of surgery, stage and path nodal status. This information may have clinical implications on selecting appropriate candidates for XRT. [Table: see text]

Randomized comparison of adjuvant aromatase inhibitor (AI) exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Joint analysis of IBCSG TEXT and SOFT trials

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Background: Adjuvant endocrine therapy with AI vs T improves outcomes in postmenopausal HR+ BC. TEXT and SOFT were designed to test whether adjuvant AI improves outcomes in premenopausal women with HR+ BC treated with OFS (AI question) and to determine the value of OFS in women who remain premenopausal and are suitable for adjuvant T (OFS question). Methods: TEXT and SOFT, randomized phase 3 trials, enrolled 5,738 premenopausal women with HR+ early BC from Nov03 to Apr11 (2672 TEXT; 3066 SOFT). TEXT randomized women within 12wk of surgery to 5y E+OFS vs T+OFS; chemotherapy (CT) was optional and concurrent with OFS. SOFT randomized women to 5y E+OFS vs T+OFS vs T alone, either within 12wk of surgery if no CT planned, or within 8mo of completing (neo)adjuvant CT. OFS was by choice of 5y triptorelin, oophorectomy, or ovarian irradiation. The primary endpoint is disease-free survival (DFS: randomization until invasive local, regional, distant recurrence, or contralateral breast; 2nd malignancy; death). Due to low event rates, protocol amendments in 2011 changed the analysis plans to answer the AI question (E+OFS vs T+OFS) by joint analysis of TEXT and SOFT. By Q3’2013 with >5y median follow-up, 436 DFS events were projected, providing 84% power for HR=0.75 with E+OFS vs T+OFS (stratified logrank 2-sided α=0.05). Results: At 5.7y median follow-up, 514 (11%) DFS events were reported in the ITT population comparing E+OFS (n=2346) vs T+OFS (n=2344). Patients assigned E+OFS had significantly reduced DFS hazard (HR=0.72; 95% CI, 0.60-0.86; P=0.0002) vs T+OFS; 5y DFS was 91.1% vs 87.3%. Reductions were similar for secondary endpoints of BC-free interval (HR=0.66 (0.55-0.80) 5y BCFI 92.8% vs 88.8%) and distant recurrence-free interval (HR=0.78 (0.62-0.97)), though not overall survival (HR=1.14 (0.86-1.51)) at this early follow-up (194 (4%) deaths). Grade 3-4 targeted AEs were reported in 31% E+OFS vs 29% T+OFS patients. Conclusion: In premenopausal women with HR+ BC, adjuvant treatment with E+OFS significantly reduced the risk of recurrence compared to T+OFS. Clinical trial information: NCT00066703 / NCT00066690 .

Array CGH and DNA sequencing to personalize targeted treatment of metastatic breast cancer (MBC) patients (pts): A prospective multicentric trial (SAFIR01)

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Background: The aim of the present study was to profile the metastatic lesion of pts using high throughput technologies, and to treat them accordingly. Methods: SAFIR01 trial aimed to include 400 pts with MBC, selected for not presenting a progressive disease at the time of biopsy. A biopsy was done in a metastatic site. DNA was extracted if the tumor contained >50% cancer cells, and sent to one of the 5 genomic centers who performed array CGH (copy number changes) and sanger sequencing on PIK3CA (exon 10/21) and AKT1 (exon 3). A targeted therapy matched to the genomic alteration was expected to be proposed at the time of progressive disease. The primary endpoint was the % of pts who received a targeted therapy according to the genomic alteration. Results: A biopsy of metastatic site was done successfully in 408 out of the 423 included pts. Biopsy was complicated by a serious adverse event in 9 pts. A discrepancy between primary and metastatic lesion was observed in 8% and 19% of pts for Her2 and HR. Array CGH and sequencing were successfully obtained in 277 (68%) and 295 (72%) pts. The main reason for failure of genomic test was the low cellularity (n=93). A targetable genomic alteration was identified in 204 pts. The most frequent genomic alterations were PIK3CA mutations, CCND1, FGF4 and FGFR1 amplifications. 76 pts presented a rare targetable genomic alteration (<5%), including AKT1 mutations, EGFR, FGFR2, PIK3CA, MDM2 amplifications. Early Feb 2013, 4 6 out of 277 pts with genomic analyses (17%) had received a targeted therapy matched to the genomic alteration, covering twelve different targets. Updated results on number of pts treated, together with efficacy data will be presented. Next generation sequencing on metastatic lesions is ongoing and results will be presented. Conclusions: This trial evaluated the concept of personalized medicine for MBC and provided a large scale genomic analysis of metastatic tissue. This study suggests that assessing the biology of metastatic tissue could allow driving pts to targeted therapy. A randomized trial (SAFIR02) testing this approach is expected to start during summer 2013. Clinical trial information: NCT01414933.

SOLTI NeoPARP: A phase II, randomized study of two schedules of iniparib plus paclitaxel and paclitaxel alone as neoadjuvant therapy in patients with triple-negative breast cancer (TNBC)

1011

Background: Iniparib is an anticancer agent with a mechanism of action still under investigation. A phase 2 randomized neoadjuvant study in patients (pts) with TNBC was designed to explore the activity and tolerability of two schedules of iniparib with weekly paclitaxel (PTX). Here we report the efficacy and safety results from a planned interim analysis (IA). Methods: The trial accrued a total of 141 pts in October 2011, of whom, 74 are included in this IA. All were chemo-naive, histologicallyconfirmed Stage II-IIIA TNBC (IIA 47%; IIB 35%; IIIA 16%) with a median age of 50 yr. Triple negative status was centrally confirmed [ER/PR <10%, HER2 IHC (0+, 1+) or FISH negative]. Pts were randomized (1:1:1) to receive weekly PTX (80 mg/m2, IV, d 1; N=25) alone or in combination with iniparib, either on a once weekly (QW) (11.2 mg/kg, IV, d 1; N=25) or twice weekly (BIW) (5.6 mg/kg, IV, d 1, 4; N=24) schedule. The total planned treatment duration was 12 wks. The IA endpoint is pathological complete response in the breast (pCR) as assessed by independent pathologists. Results: Two/2/3 pts in the PTX/QW/BIW arms, respectively, discontinued due to progressive disease per RECIST. Another 3/2/2 pts, respectively, discontinued due to investigator decision or an adverse event (AE). Thirteen pts presented with Grade 3/4 Treatment Emergent AE: 3 pts in PTX arm (1 neutropenia, 1 presyncope, 1 ALT elevation), 3 in QW arm (1 lymphopenia, 1 hyperkalemia, 1 pulmonary embolism), and 8 in the BIW arm (1 febrile neutropenia, 3 neutropenia, 1 aphonia, 1 syncope, 1 radius fracture and 1 vertigo). Laboratory Grade 3/4 neutropenia occurred in 4% of pts in PTX, 0% in QW and 21% of BIW arms, with 1/2/3 pts, respectively, requiring G-CSF usage. There were 4/7/6 pts in the PTX/QW/BIW arms with PTX dose modifications. Four pts (16%) in PTX arm, 4 pts (16%) in the QW arm and 6 pts (25%) in the BIW arm had confirmed pCR in the breast. Conclusions: In this IA population, the addition of iniparib regardless of the schedule to weekly PTX did not seem to add clinically significant toxicity. pCR rate in the breast is similar across treatment arms at this IA. NCT01204125.

ASTER 70s: Benefit of adjuvant chemotherapy for estrogen receptor-positive HER2-negative breast cancer in women over 70 according to genomic grade—A French GERICO/UCBG UNICANCER multicenter phase III trial

TPS667

Background: The benefit of adjuvant chemotherapy (CT) is highly controversial for elderly breast cancer (BC) women presenting with an oestrogen receptor-positive (ER+) HER2-negative (HER2-) phenotype. Conversely to hormonal treatment (HT) that remains the cornerstone of adjuvant treatment for such luminal tumours, CT may severely decompensate comorbidities and alter quality of life in elderly patients. As disappointing as it is in drug development, elderly have been constantly excluded from trials evaluating new modern prognosis classifiers. This prospective multicentre trial funded by a French national grant (PHRC 2011) is the first phase III trial to investigate the impact on overall survival (OS) of adjuvant CT in elderly ER+ HER2- BC patients selected with a modern prognosis classifier and taking into account competing risks for mortality (EudraCT 2011-004744-22). Methods: Following surgery, 2,000 women 70+ with ER+ HER2- BC (any pT/pN), will have a genomic grade (GG, derived from frozen MapQuantDx™, Ipsogen) centrally assessed on formalin-fixed paraffin-embedded samples. Only those with a high GG (estimation~700) will be randomized between HT alone vs CT followed by HT. CT regimen is left to the choice of investigators amongst 3 regimen of same duration [4 q3w cycles, docetaxel+cyclophosphamide, doxorubicin or non pegylated liposomal doxorubicin (Myocet)+cyclophosphamide, all with G-CSF], as well as HT (aromatase inhibitor±tamoxifen). Those with low GG or not included for other reasons (estimation~1,300) will be followed as an observational parallel cohort with HT alone. Sample size is based on 4-year OS as primary endpoint (87.5 vs 80%), bilateral α=0.05, β=0.20 and HR= 0.60. Secondary endpoints include assessment of competing risks for mortality, cost-effectiveness and Q-TWiST analysis, geriatric items (e.g. Lee’s 4-year mortality score and G8 screening tool), acceptability, quality of life (QLQ-C30 and specific elderly scale ELD15), and translational research on ageing/prognostic biomarkers and pharmacogenetic. The trial has been just opened to inclusion in February 2012.

Therapeutic effects of the aromatase inhibitor fadrozole hydrochloride in advanced breast cancer

The endocrine and therapeutic effects of the aromatase inhibitor fadrozole hydrochloride have been assessed in 80 post-menopausal patients with recurrent breast cancer after tamoxifen failure. Treatment allocation was randomly 0.5, 1.0 or 2.0 mg orally b.d. Eight patients were not assessable for response. All patients were evaluated for toxicity (intent-to-treat analysis). In general, the patients' characteristics were well balanced between the three randomised groups. The endocrine data from this study previously reported suggest a dose-related suppression of oestrone, but not oestradiol or oestrone sulphate. The objective response rate was 17% (95% CI 8.9-27.3%) with no complete responders. Fifteen patients (21%) had stable disease (NC) and 45 patients (63%) had progressive disease (PD). The median duration of objective response was 36 weeks. The median time to treatment failure was 12.7 weeks. The log-rank test showed no statistical difference between the dosage groups. The main adverse events reported were mild to moderate severity: nausea in 11 patients (15%), hot flashes in four (5%) and somnolence in three (4%). No serious adverse events were reported. In conclusion, fadrozole is a clinically active aromatase inhibitor with a low incidence of side-effects and phase III clinical trials in post-menopausal women are currently under way.