Abstract P4-22-09: A phase 2 open label study of everolimus in combination with endocrine therapy in resistant hormone receptor-positive HER2-negative advanced breast cancer

Background: Therapies targeting estrogen receptor (ER) signaling are standard for patients (pts) with hormone receptor positive (HR+) (ER and/or progesterone receptor [PR] positive) metastatic breast cancer (MBC). Dysregulation of the mammalian target of rapamycin (mTOR) pathway has been associated with endocrine therapy (ET) resistance. BOLERO-2 demonstrated that the addition of the mTOR inhibitor, everolimus (EVE), to exemestane doubled the PFS in HR+ HER2- MBC pts who previously progressed on nonsteroidal aromatase inhibitor therapy.The premise of this phase 2 trial in HR+ MBC is that the addition of EVE to the last ET on which the disease progressed may restore sensitivity to ET and extend the benefit of the anti-estrogen therapy.

Methods: Pts ≥18 yrs with HR+, HER2- unresectable, locally recurrent, or MBC refractory to ET in either the adjuvant or advanced/metastatic setting. 0-1 chemotherapy (chemo) regimens for MBC were permitted. Post-/ pre-/peri-menopausal women were eligible with ovarian function suppression permitted. Additional eligibility requirements include: no prior mTOR inhibitor therapy, measurable or evaluable disease, ECOG ≤2, adequate bone marrow and organ function. EVE (10 mg PO daily) was administered on a 4-wk cycle in combination with the same dose and schedule of the last ET to which their disease became resistant. Disease assessments were performed every 2 cycles and treatment continued until disease progression or unacceptable toxicity. Blood samples and archival tumor were collected respectively for the VeriStrat Assay and for the Foundation One molecular profiling platform.

Results: 48 pts were enrolled; data from 26 pts is presented. Median age 63.5 yrs (range, 36-81) with 46% ≥ 65 yrs. 14 (54%) pts had received chemo in the adjuvant setting, 9 pts (35%) received chemo for MBC, and 4 pts (15%) received chemo in both settings. All pts had at least 1 prior hormonal therapy; 9 pts received ≥ 3 hormonal agents. EVE was combined with tamoxifen (27%), AIs (61%), and fulvestrant (12%). Median time on treatment was 18.6 wks (range 1-48.9 weeks). 5 pts (19%) remain on treatment and 21 (81%) have discontinued therapy due to: disease progression - 17, toxicity -2, and other causes - 2. 23 pts were evaluable for response. 1 pt on fulvestrant plus EVE had a PR and 18 pts (78%) had SD as best response, with SD > 6 mos in 7 pts, for a clinical benefit rate (CR+PR+ SD ≥ 6 months) of 35%. With a median follow up of 11 mos (range 2-16 mos), the median PFS was 6.6 months (range 3.6-9.4); the median OS has not been reached. Treatment-related adverse events consisted mostly of stomatitis, rash and fatigue with few G3 events: stomatitis 3 pts, rash 2 pts, and 1 each of fatigue, edema, and neutropenia. G1 pneumonitis was present in 2 pts. There were no G4 events or treatment related deaths.

Conclusions: In HR+ HER2- advanced/MBC patients who progressed on prior ET, the addition of EVE to the ET to which their disease became resistant, resulted in 1 PR and 7 pts with SD > 6 mos. The results of the full study population will be presented. Modulation of the mTOR/AKT/PI3K pathway with EVE may extend the benefit of ET, even after tumor progression on ET alone.

Citation Format: Yardley DA, Blakely L, Hemphill B, Joseph M, Liggett W, Daniel B, Castrellon A, Shastry M, Finney L, DeBusk L, Hainsworth JD, Burris III HA. A phase 2 open label study of everolimus in combination with endocrine therapy in resistant hormone receptor-positive HER2-negative advanced breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-09.

Abstract P1-14-06: A phase II randomized study with eribulin/cyclophosphamide (ErC) and docetaxel/cyclophosphamide (TC) as neoadjuvant therapy in HER2-negative breast cancer- Final analysis of primary endpoint and correlative analysis results

Background: Eribulin mesylate (Er) is a non-taxane inhibitor of microtubule growth that results in G2-M cell cycle arrest, disruption of normal mitotic spindles and apoptosis. Er demonstrated an overall survival (OS) but not progression free survival (PFS) advantage in anthracycline and taxane refractory breast cancer pts. This OS rather than PFS benefit has been attributed to Er's potential to suppress new metastases through its effects on the epithelial mesenchymal transition (EMT) pathway, even in the absence of an effect on the primary tumor or established metastases. In this study ErC was compared to TC, a standard regimen for (neo) adjuvant treatment. A companion exploratory analysis examined the EMT markers E-cadherin and vimentin, as well as the endothelial marker CD-31 assessing tumor vasculature. Final assessments of the primary endpoint of pathological complete response (pCR) and results of the correlative studies will be presented.

Methods: Women with histologically confirmed invasive HER2-negative (IHC 0-1+ or FISH/SISH negative), cT1-3, cN0-2, M0 (pN3a disease allowed) adenocarcinoma of the breast were eligible. Following a 10 pt lead-in to confirm the safety/feasibility of ErC, pts were randomized 2:1. Arm 1, Er 1.4 mg/m2 IV (Days 1 & 8) and C 600 mg/m2 IV (Day 1); Arm 2, T 75 mg/m2 IV and C 600 mg/m2 IV on Day 1, both regimens administered q 21 days x 6 cycles followed by surgery. Tumor samples were collected at baseline and from residual breast cancer at the time of surgery. Samples were assayed for E-cadherin, vimentin, and CD-31 expression by immunohistochemistry.

Results: Enrollment was completed 4/2014 (76 pts); 10 pts in lead-in phase, 66 pts were randomized (Arm 1, 44; Arm 2, 22). In the randomized population, 77% had invasive ductal adenocarcinoma; median tumor size 3.1 cm (range, 0.4-10cm; 29.5% were T3); axillary nodes clinically positive in 52%. 34% of pts were triple negative (TN). 59 pts (89%) underwent surgery after receiving neoadjuvant chemotherapy (NAC) on study. pCR rates were 9% and 18% on the TC and ErC arms respectively. 4/7 pts with pCR on the ErC arm were TN. tumor samples were analyzed from 69 pts (including lead-in pts) for expression of the EMT biomarkers. Of these, 40 pts had paired pre- and post-treatment samples, and 29 pts had either a pre- or post-treatment sample (including 8 pre-treatment samples from pts who achieved pCR). In pre-treatment tumor specimens (61 samples), E-cadherin levels were modest-high in 80%, vimentin expression was seen in 39%, and CD-31 expression observed in 21% of the samples. Analysis of pre- and post-treatment paired specimens and differential effects according to treatment regimen will be presented.

Conclusion: The observed pCR rate of 18% with ErC in this HER2- pt population was comparable with other NAC regimens. Correlative evaluation of EMT markers and tumor vascular density with response is ongoing and will be presented.

Citation Format: Yardley DA, Chandra P, Hart L, Wright GS, Ward P, Mani A, Shastry M, Finney L, Guo S, DeBusk LM, Hainsworth JD, Burris III HA. A phase II randomized study with eribulin/cyclophosphamide (ErC) and docetaxel/cyclophosphamide (TC) as neoadjuvant therapy in HER2-negative breast cancer- Final analysis of primary endpoint and correlative analysis results. [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 P1-14-06.

The Bionanoprobe: hard X-ray fluorescence nanoprobe with cryogenic capabilities

Hard X-ray fluorescence microscopy is one of the most sensitive techniques for performing trace elemental analysis of biological samples such as whole cells and tissues. Conventional sample preparation methods usually involve dehydration, which removes cellular water and may consequently cause structural collapse, or invasive processes such as embedding. Radiation-induced artifacts may also become an issue, particularly as the spatial resolution increases beyond the sub-micrometer scale. To allow imaging under hydrated conditions, close to the `natural state', as well as to reduce structural radiation damage, the Bionanoprobe (BNP) has been developed, a hard X-ray fluorescence nanoprobe with cryogenic sample environment and cryo transfer capabilities, dedicated to studying trace elements in frozen-hydrated biological systems. The BNP is installed at an undulator beamline at sector 21 of the Advanced Photon Source. It provides a spatial resolution of 30 nm for two-dimensional fluorescence imaging. In this first demonstration the instrument design and motion control principles are described, the instrument performance is quantified, and the first results obtained with the BNP on frozen-hydrated whole cells are reported.

Abstract OT1-1-13: A phase II study with lead-in safety cohort of cabazitaxel plus lapatinib as therapy for patients with HER2-positive metastatic breast cancer (MBC) and intracranial metastases

Background: HER2-targeted therapy has improved the progress of patients (pts) with HER2-positive breast cancer; however, CNS metastases remain a significant source of morbidity and mortality. It is hypothesized that the inability of drugs like trastuzumab to cross the intact blood-brain barrier (BBB) may render the CNS as a sanctuary site for metastases. Lapatinib is an oral small molecule tyrosine kinase EGFR1/HER2 inhibitor that crosses the BBB and has activity against CNS metastases. Cabazitaxel is a new taxoid that is active in docetaxel- or paclitaxel-resistant breast cancer, and differs from other taxanes in its ability to cross the BBB. The promising systemic activity shown by cabazitaxel in taxane-resistant MBC coupled with the CNS penetrance of both cabazitaxel and lapatinib make this an attractive combination to evaluate in HER2-positive MBC pts with CNS metastases.

Study Objectives: The primary objectives of the study are to determine the safety and CNS objective response rate (ORR = CR+PR) in HER2-positive MBC pts with CNS metastases when treated with cabazitaxel and lapatinib. The secondary objectives include evaluation of the clinical benefit rate (CBR), 3- and 6-month PFS rate for CNS metastases, and response rate and CBR for extra-cranial metastases.

Key eligibility: Pts >18 yrs with HER2-positive (IHC 3+ or FISH/SISH-positive) MBC and unequivocal evidence of brain metastases are eligible. Additional eligibility criteria include: at least one measurable brain lesion >1.0cm in longest dimension on MRI; pts with brain lesions previously treated with WBRT and/or SRS must have at least one intra-cranial lesion >1.0cm not treated with SRS and must have evidence of intra-cranial progressive disease. Pts must have received at least 1 prior HER2-directed therapy in the adjuvant or metastatic setting; pts without prior chemotherapy for MBC are eligible if they progressed during or within 6 months of adjuvant therapy. Otherwise, there is no specific minimum or maximum number of previous chemotherapy regimens for MBC. ECOG performance status 0-2, adequate renal, bone marrow, and hepatic function are required; prior treatment with cabazitaxel or lapatinib (for MBC) not permitted.

Trial design: This is an open-label, non-randomized, phase II study with a lead-in safety cohort. During the lead-in phase, 6-15 pts will be treated in cohorts of 3 with increasing doses of cabazitaxel and lapatinib to determine the tolerability and optimal dose. Once the safety and dose is confirmed, subsequent pts will be treated at the optimal dose of the 2 agents. Each treatment cycle is 3 weeks and restaging will occur systemically and intra-cranially every 2 cycles for the first 8 cycles and every 3 cycles thereafter until progressive disease or unacceptable toxicity.

Statistical methods: We hypothesize that the addition of cabazitaxel will increase the CNS ORR from 6% (expected with single agent lapatinib) to ≥20% in this pt population. Treatment of 27 evaluable pts with the identified phase II doses will detect this difference with a power of 80% and alpha = 10% (one-sided test). Accounting for a 10% inevaluable rate and lead-in pts, a total of 45 pts will be enrolled on the study.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT1-1-13.

Abstract P4-16-04: Amrubicin as second- or third-line treatment for patients with HER2-negative metastatic breast cancer (MBC): Final results from a phase II trial of the Sarah Cannon Research Institute (SCRI)

Background: Anthracyclines are among the most effective agents in the treatment of breast cancer; however, dose-dependent cumulative cardiotoxicity limits their use. Amrubicin is a synthetic anthracycline topoisomerase II inhibitor demonstrating potent antitumor effects coupled with little potential for cardiotoxicity. We report the final results from a phase I/II trial of amrubicin as second- or third-line therapy for HER2-negative MBC.

Methods: Eligible patients (pts) included women with measurable HER2-negative MBC who had received 1 or 2 prior chemotherapy regimens for MBC. Previous anthracyclines were permitted if ≥ 6 months prior to study entry. Normal LVEF was required. Amrubicin 110 mg/m2 IV (dose established from phase I portion) was administered every 3 weeks until disease progression or intolerable toxicity; growth factor use was permitted. Disease evaluations were performed every 6 weeks and LVEF assessments every 12 weeks. Progression-free survival (PFS) was the primary endpoint; a median PFS ≥ 4.5 months would merit further evaluation of amrubicin in MBC. Toxicity, overall survival, and overall response rate (ORR) were secondary endpoints.

Results: Between 1/2010 and 3/2012, 78 pts were enrolled, and 66 pts are included in this analysis (ph I: 3 pts; ph II 63 pts). Baseline characteristics included: median age 59 years; hepatic metastases in 50%; ≥ 3 sites of metastatic disease in 32%. Triple-negative histology was noted in 27%; prior adjuvant chemotherapy in 50%; prior anthracyclines in 32%; and 2 prior cytotoxic regimens for MBC in 35%. Median treatment duration was 18 weeks (6 cycles), range 1- 24 cycles. The ORR was 21% in evaluable pts (2 CR, 10 PR); 5 of these 12 pts had prior anthracyclines. 14% were not evaluable. The clinical benefit rate (CBR) was 42% (CBR = CR+PR+SD≥ 4 months); 35% of these responders received ≥12 cycles of amrubicin. Median PFS for all pts was 4.0 months (95% CI 2.5- 5.8 months) and did not significantly differ by line of therapy administered (4.0 months as 2nd line vs 4.7 as 3rd line therapy). 36% of pts were free of progression at 6 months. Neutropenia was the most common grade 3/4 toxicity present in 42% and accompanied by fever in 7%. No grade 3/4 non-hematologic toxicity occurred in > 5% pts. One pt previously treated with anthracyclines experienced a transient 20% LVEF decline to 44% at cycle 4. This recovered to baseline within 2 weeks and pt continued to receive 2 additional cycles of amrubicin before experiencing PD. No other grade 3/4 cardiac events were noted. In 3 pts, amrubicin was discontinued due to toxicity (G4 neutropenia, G2 thrombocytopenia, G2 nausea/vomiting/vertigo).

Conclusions: Amrubicin was active and well tolerated in the second- or third-line MBC setting with manageable toxicity. The ORR of 21% and median PFS of 4 months are comparable to other single agents in this setting. The observed CBR of 42%, and the fact that nearly 1/3 of these responders received ≥12 cycles of amrubicin with no cardiotoxicity, suggests that future evaluations of amrubicin in breast cancer are warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-04.

Abstract P5-17-05: Sorafenib plus Ixabepilone as First-Line Treatment for Patients with HER2-Negative Metastatic Breast Cancer: Preliminary Results of the Phase II Trial of the Sarah Cannon Research Institute

Background: Sorafenib (S) is an oral multi-kinase inhibitor with effects on tumor proliferation and angiogenesis, targeting VEGFR1 and VEGFR2. It has modest activity as a single agent in breast cancer. In combination with capecitabine, S demonstrated a significant improvement of 2.3 months in progression free survival (PFS) in patients (pts) with metastatic breast cancer (MBC) and added benefit when combined with paclitaxel. Ixabepilone (Ixa) is a semi-synthetic analog of epothilone B with excellent single agent activity in MBC. The phase I portion of this trial identified the MTD of the Ixa and S combination. We now report the initial results of the phase II trial with this novel combination.

Methods: Eligibility criteria included: HER2-negative MBC previously untreated with chemotherapy; measurable disease; ECOG PS 0–2; normal LVEF; and adequate bone marrow and organ function. Prior hormonal therapy for MBC was permitted. Pts received Ixa 32mg/m2 IV on day 1 of each 21-day cycle and S 400mg PO BID. Following a minimum of 4 cycles of the combination, responding pts could discontinue Ixa and remain on study treatment with S monotherapy. Granulocyte-stimulating growth factors were permitted after cycle one. Tumor assessments were performed every 9 weeks. Pts continued study treatment until disease progression or unacceptable toxicity. The primary endpoint of this trial was PFS; the addition of S to Ixa was hypothesized to improve PFS from 4.2 month to 6.2 months in this patient population. The total enrollment goal is 85 pts, and the trial is currently open to accrual.

Results: Between 5/2010 and 4/2012, 76 pts have been enrolled, and 57 pts (56 females, 1 male) are included in this analysis. Baseline characteristics included: median age 58; 61% were ER and/or PR positive; 39% were triple-negative; 39% received neoadjuvant therapy. Anthracycline exposure was noted in 34 pts and prior taxane exposure in 39 pts. 29 pts received prior hormonal therapy, 7 of these for MBC. Sites of metastatic disease included lymph nodes 42%, lung 35%, liver 30%, bone 30%, and 23% other. 19 pts (33%) had 3 or more sites of metastatic disease. Median treatment duration was 3 cycles (9 weeks), range 1–11+ cycles with 9 pts discontinuing Ixa after a median of 6 cycles and continuing on S monotherapy. 12 pts (21%) had objective responses (1 CR, 11 PR); 3 of the 22 (14%) triple-negative patients had responses (1 CR, 2 PR). An additional 24 patients (42%) had stable disease at first reevaluation. Neutropenia was the most common grade 3/4 toxicity (26%) with growth factor use reported in 35%. Grade 3/4 non-hematologic toxicity occurring in > 5% of patients consisted of: rash (12%), fatigue (11%), hypersensitivity reaction (7%, Ixa= 3 pts and S= 1 pt), and neuropathy (7%). Discontinuation due to adverse events occurred in 11%.

Conclusion: The combination of Ixa and full dose S was well tolerated with no new observed toxicities. Adverse events were manageable and consisted primarily of G3/4 neutropenia and rash. Study is ongoing and updated results will be presented.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-17-05.

Abstract OT3-3-08: Eribulin/Cyclophosphamide versus Docetaxel/Cyclophosphamide as Neoadjuvant Therapy in Locally Advanced HER2-Negative Breast Cancer: A Randomized Phase II Trial of the Sarah Cannon Research Institute

Background: Neoadjuvant chemotherapy for locally advanced breast cancer improves survival and rates of breast-conserving surgery. Pathologic complete response (pCR) after neoadjuvant therapy strongly correlates with improved disease free survival (DFS) and provides an early indicator of treatment efficacy. The expected pCR rate with a standard taxane-containing combination is approximately 18%. Eribulin is a non-taxane synthetic analogue of halichondrin B that inhibits microtubule dynamics by a novel mechanism of action distinct from other tubulin-targeting agents. Eribulin is active against taxane and anthracycline pretreated metastatic breast cancer (MBC) and is well tolerated with a predictable toxicity profile. Substitution of eribulin for docetaxel in a neoadjuvant combination regimen may therefore improve efficacy. This study will evaluate the non-anthracycline eribulin/cyclophosphamide (ErC) and docetaxel/cyclophosphamide (TC) combinations as neoadjuvant therapy. The first ten patients (pts) will be evaluated for tolerability and feasibility of standard prescribed eribulin monotherapy dosing in combination with standard dose cyclophosphamide.

Study Objectives: This randomized phase II trial is designed to determine the pCR rate of locally advanced, HER2-negative breast cancer treated with 6 cycles of ErC or TC. The secondary objectives are to evaluate the clinical response rate of ErC as neoadjuvant therapy and to determine the 2 year DFS of pts treated with ErC and TC.

Eligibility: Females ≥ 18 years with untreated, locally advanced, HER2-negative breast cancer appropriate for neoadjuvant chemotherapy are eligible. Eligibility criteria include: adenocarcinoma histology; clinical T1-3, N0-2, M0 breast tumors; ECOG PS 0–2; known hormone receptor status at study entry; adequate bone marrow and organ function; willingness to provide archived biopsy specimen for correlative testing. Clinical N3, T1N0M0, and T4 tumors are excluded. Upfront axillary lymph node sampling and/or definitive nodal surgery is permitted, and demonstrated pN3a disease is allowed.

Trial Design: A lead-in phase of the trial will enroll 10 pts to be treated with ErC to determine safety and feasibility of the combination. If the safety is confirmed, subsequent pts will be stratified by hormone receptor status (positive vs. triple- negative) and will be randomized in a 2:1 ratio to Arm 1: ErC or Arm 2: TC. Pts on Arm 1 will receive eribulin 1.4 mg/m2 IV (Days 1 & 8) and cyclophosphamide 600 mg/m2 IV (Day 1). Pts on Arm 2 will receive docetaxel 75 mg/m2 IV (Day 1) and cyclophosphamide 600 mg/m2 IV (Day 1). Both regimens are repeated every 21 days for a total of 6 cycles. After completion of neoadjuvant chemotherapy, pts will undergo definitive local surgery, as determined by the treating surgeon. Archival tumor samples and residual tumor tissue at surgery will be collected for biomarker evaluations. A total of 66 pts (Arm 1: 44; Arm 2: 22) will be enrolled to this study. A pCR rate ≥ 18% in patients treated with ErC is considered a study result that merits further evaluation. This trial is pending activation and has a total accrual goal of 76 pts.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT3-3-08.

X-ray fluorescence microscopy for investigation of archival tissues

Several recent efforts in the radiation biology community worldwide have amassed records and archival tissues from animals exposed to different radionuclides and external beam irradiation. In most cases, these samples come from lifelong studies on large animal populations conducted in national laboratories and equivalent institutions throughout Europe, North America, and Japan. While many of these tissues were used for histopathological analyses, much more information may still be obtained from these samples. A new technique suitable for imaging of these tissues is x-ray fluorescence microscopy (XFM). Following development of third generation synchrotrons, XFM has emerged as an ideal technique for the study of metal content, speciation, and localization in cells, tissues, and organs. Here the authors review some of the recent XFM literature pertinent to tissue sample studies and present examples of XFM data obtained from tissue sections of beagle dog samples, which show that the quality of archival tissues allows XFM investigation.

Performance evaluation and testing of digital intra-oral radiographic systems

Four digital intra-oral radiographic systems were tested and evaluated; three charge-coupled device (CCD) based systems from RVG, Visualix and Sidexis and a photostimulable phosphor (PSP) system from DenOptix. Image quality was assessed using three purpose-built phantoms to measure uniformity, low contrast detail detectability and signal-to-noise ratio (SNR). Limiting resolution was measured using a 20 lp mm(-1) bar pattern. Radiation output inaccuracies caused difficulties in achieving optimum doses for CCD systems. However, the accuracy was improved by using K-edge filters. SNR measurements proved to be a useful tool in assessing system performance. Each system has specific attributes: resolution was highest for the RVG system, the Visualix system measured the highest SNR and the lowest exposure settings were on the Sidexis system. Test methods and phantoms developed are suitable for acceptance testing and commissioning digital dental X-ray systems and for programming each system to produce an optimum level of image quality.