Pharmacogenomic analysis of needle biopsies obtained before preoperative docetaxel/capecitabine/FEC (TX/FEC) chemotherapy for breast cancer

10595

Background: Our goal was to evaluate the feasibility of obtaining fine needle biopsies, for pharmacogenomic analysis, in community based oncology practices and develop gene expression-based predictors of pathologic complete response (pCR) to preoperative sequential docetaxel/capecitabine and 5-fluorouracil, epirubicin, cyclophosphamide chemotherapy. Methods: One hundred seventy-five patients were accrued at 29 sites in the US Oncology Research network. FNA specimens were mailed to a central laboratory (MDACC) and gene expression profiling was performed on Affymetrix U133A chips. Results: RNA extraction was started on 140 specimens, 112 of these (80%) yielded ≥1 μg total RNA, 69 were hybridized and 65 (94%) gene expression profiles have passed quality control as of abstract submission date. The analysis plan is to develop a multigene predictor of pCR from the first 80 cases and test its performance independently in the remaining cases. Conclusions: Collection of mandatory research FNA biopsies for pharmacogenomic research is feasible in community practice. Approximately 80% of biopsies yield sufficient RNA for gene expression profiling. In 20% of patients, either technical factors, which can be addressed, or tumor biology (necrotic, rapidly growing tumors) were limiting. Supported by Roche Laboratories, Inc., Nutley, NJ; Pfizer, New York, NY; and Precision Therapeutics, Pittsburgh, PA.

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Phase II breast cancer chemoprevention trial of the third generation selective estrogen receptor modulator arzoxifene

1001

Background: Arzoxifene (ARZ) is a third generation SERM with efficacy in metastatic breast cancer but lacking uterine agonist activity. Methods: We conducted a randomized, double-blind, placebo-controlled Phase II prevention trial in 199 high risk women assessing the effects of ARZ 20 mg/day on several risk biomarkers. Biomarkers, including cytomorphology of breast epithelial cells obtained by random periareolar FNA (RPFNA) were assessed at baseline and following 6 months of placebo or ARZ. Subjects were stratified by presence or absence of atypia, ER expression, BRCA1/2 mutation, as well as menopause status. Results: At entry, mean age was 47, 52% were premenopausal and 47% of postmenopausal women were taking HRT. Mean 10 year Gail was 6.8% and mean Masood cytology index score was 14.3. The ARZ and placebo groups were well matched. The protocol defined primary endpoint was a decrease in RPFNA cytology Masood index score by ≥3 points at 6 months and required 160 evaluable subjects for 81% power to detect a change from 30% to 52% of subjects showing improvement. For the 181 evaluable subjects, there was no significant difference in the proportion of women achieving ≥3 point improvement (19% placebo vs. 24% ARZ, p=0.46); or in change in mean index score (0.6 placebo vs. 0.9 ARZ, p=0.53). There was also no difference in grade 3 or 4 side effects or dropout prior to 6 months. However, comparing ARZ to placebo, there was favorable modulation of the two risk biomarkers, mammographic breast density (p=0.001) and IGF-1:IGFBP-3 ratio (p=0.001), and reduction in bone turnover biomarker osteocalcin (p= 0.002), but without an increase in endometrial thickness. Conclusions: Although improvement in cytomorphology after 6 months of ARZ was not shown, the acceptable side effect profile and favorable modulation of other biomarkers (breast density, IGF-1:IGFBP-3, osteocalcin) provides support for continued evaluation of ARZ as a breast cancer prevention agent.

No significant financial relationships to disclose.

The Head to Head trial: Letrozole vs anastrozole as adjuvant treatment of postmenopausal patients with node positive breast cancer

10672

Introduction: Aromatase Inhibitors (AIs) have demonstrated both efficacy and safety advantages over tamoxifen (T) in all treatment settings in breast cancer (BC) and are becoming the new standard of care as endocrine therapy for postmenopausal patients (PM) with BC. Rationale: Cumulative evidence suggests that all AIs may not be the same, raising the question of whether there is a superior AI, and whether any specific patient populations derive differing degrees of benefit from a particular AI. In the ATAC trial, evaluating anastrozole (A) in PM patients with early breast cancer (EBC), at 33 months median follow up the risk of recurrence in the hormone receptor positive (HR+) population was reduced by 22%.The BIG 1–98 Trial, evaluating letrozole (L) in PM women with EBC, showed a significant benefit in favor of L over T at a median follow up of 26 months, with a 19% reduction in the risk of recurrence; in subgroup analyses, L significantly decreased the risk of recurrence in LN+ patients and in patients who received adjuvant chemotherapy. This study is a head to head comparison of L and A in HR+, LN+ PM patients with EBC and aims to compare L vs A in the adjuvant treatment of these patients. Design and Methods: This is a Phase IIIb open-label, randomized, multicentre study including 4000 PM patients from up to 250 international sites. PM patients with HR+, LN+ BC who have recently undergone surgery for primary BC will be randomized to either receive L 2.5 mg or A 1 mg daily. Treatment will commence following completion of standard chemotherapy (if given) and concurrently with radiotherapy (if given)Patients will receive treatment until disease recurrence/relapse for up to 5 years. Patients will be stratified by number of LN and HER2 status. The primary objective is disease free survival at 5 years for L and A. Secondary objectives include safety, overall survival, time to distant metastases and time to contralateral breast cancer. Data analysis will be conducted by an independent group of investigators. Summary: Updated patient accrual figures, including any available early safety data, will be presented at the meeting.

No significant financial relationships to disclose.

Effect of the third generation selective estrogen receptor modulator arzoxifene on mammographic breast density

562

Background: Arzoxifene (ARZ) is currently being studied for treatment of breast cancer patients in a Phase II trial because of tamoxifen-like efficacy but lack of uterine agonist effect. We conducted a Phase II chemoprevention trial in women at high risk for development of breast cancer on the basis of personal or family history. Methods: Potential subjects had multiple biomarkers assessed, including random periareolar fine needle aspiration (RPFNA) with breast epithelial cells processed for cytomorphology and immunocytochemistry. Women who exhibited cytologic hyperplasia ± atypia were eligible for enrollment. Subjects were stratified on the basis of atypia, estrogen receptor expression, menopause status, germline BrCa1/2 mutation status, and accrual site. Subjects were randomized (double-blind) between placebo and ARZ (LY353381.HCI, 20 mg daily) for 6 mo, with an option to continue on study for another 6 mo while receiving open-label ARZ. Assessments conducted at baseline, 6 mo, and 12 mo included mammographic breast density. Mammograms were digitized to image files which were cropped to remove labels and dates, and then identified by a study subject ID number and a random coding for baseline, 6 or 12 mo. This allowed the reader (GU) to view the three files for a subject, but to remain blinded as to the sequence of the films or the study agent. The files were assessed for mammographic density using the Madena computer-assisted system. Results: Of 199 subjects enrolled on the study, 52% were pre-menopausal; with 101 women randomized to placebo and 98 to ARZ. At baseline, mean values were comparable for placebo and ARZ groups for breast area (∼244 cm2), total dense area (∼100 cm2), and the percent of the breast at increased density (41.3% vs 46.2%). After 6 mo, there were minimal changes in total breast area (P=0.13); but statistically significant decreases (P<0.001) for the comparison of placebo vs ARZ (2-sided T-test) for change in both dense area (+3.8 vs −12.9 cm2) and percent breast density (+0.8% vs −4.6%). Conclusions: The 3rd generation SERM arzoxifene administered for 6 mo produces statistically significant decreases in mammographic breast density relative to placebo in women at high risk for development of breast cancer.

No significant financial relationships to disclose.

Feasibility of testing core needle biopsies ex vivo in the ChemoFx assay

20073

Background: Multiple chemotherapy options exist for the treatment of primary breast cancer. While response rates are good, many patients are treated with unnecessary or ineffective chemotherapy. Inadequate treatments are partly due to the lack of accurate predictors of response in individual patients. To predict an individual’s response to therapy, ex vivo chemosensitivity and resistance assays (CSRAs) have long been evaluated, but have been limited by technical difficulties, including the need for large (1–2 gm) amounts of fresh tissue. However, these problems have largely been overcome with new technology. Novel methods used in Precision Therapeutics’ ChemoFx assay allow for testing smaller amounts of tissue (35 mg). The reduced tissue requirement is crucial in the breast cancer setting, as the diagnosis is often made by percutaneous biopsy. The goals of the study were to determine the growth success rate of culturing epithelial cells from breast tissue core needle biopsies and the feasibility of testing the cells in the assay. Methods: A prospective feasibility study involving women with invasive primary breast cancer. One to four core needle biopsy specimens were collected using a 14 gauge needle (est. per patient yield <50 mg) and submitted to Precision Therapeutics. A primary culture of each specimen was established and the ex vivo chemoresponse profiles of each culture were evaluated. Drugs tested included capecitabine, cisplatin, cyclophosphamide, docetaxel, doxorubicin, epirubicin, etoposide, 5-fluorouracil, gemcitabine, irinotecan, paclitaxel, and vinorelbine. Results: 21 of 25 (84%, 95% CI: 68% to 97%) specimens grew successfully; all 21 were tested for chemoresponsiveness with the assay. Of the 4 subjects with unsuccessful ex vivo cultures, 2 had no growth, 1 failed plating for culture, and 1 failed IHC testing due to overgrowth of non-epithelial cells. The average number of drugs tested for each specimen was 7 (range: 1–15). Conclusions: This study demonstrates that core needle biopsies from primary breast tumors can be successfully cultured and tested for chemoresponsiveness using the ChemoFx assay. The ability to perform ex vivo chemoresponse testing on core needle biopsies greatly increases the utility of the assay in adjuvant or neoadjuvant primary breast cancer settings.

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