Abstract P6-09-01: Central Ki67 analysis as a predictor for adjuvant capecitabine efficacy in early breast cancer (EBC) subtypes in US oncology trial 01062

Background: USON 01062 (O’Shaughnessy J, et al. Proc SABCS, 2010, abst S4-2) showed no improvement in the primary endpoint of disease-free survival (DFS) (median FU 5 yrs: HR 0.84, 95% CI: 0.67-1.05; p = 0.125) with the addition of capecitabine (X) to standard adjuvant chemotherapy, but showed improvement in OS (HR 0.68, 95% CI: 0.51-0.92; p = 0.011). Exploratory analysis of local pathology-assessed Ki67 suggested benefit from adjuvant X in pts with more highly proliferative cancers with Ki67 ≥ 10% (Pippen J et al. Proc ASCO, 2011, abst 500). The objective of this study is to determine whether centrally-performed Ki67 IHC results corroborate or refute this finding.

Methods: 2610 pts with resected high risk EBC were randomized to receive 4 cycles of AC (doxorubicin 60mg/m2 and cyclophosphamide 600mg/m2) IV every 3 wks for 4 cycles followed by either docetaxel 100mg/m2 IV or docetaxel 75mg/m2 IV plus X 825mg/m2 PO bid for 14 days every 3 wks for 4 cycles. Archival primary breast cancer tissue was collected on 2000 pts for predictive biomarker analyses. Central Ki67 IHC was performed using the anti-Ki67 monoclonal antibody SP6 and was read by one pathologist (HK) according to published recommendations (Dowsett M, et al. JNCI 103:1-9, 2011).

Results: Central Ki67 IHC has been performed on 1440 pts who had centrally-validated informed consents. The distribution of% Ki67-positive cells by locally-assessed ER/HER2 subtype is shown below. 45% of HR+ HER2- BCs had a Ki67 ≤ 10%, while 24% had a Ki67 11% to 20%, and 31% had a Ki67 > 20%. The concordance between the local vs central Ki67 results was low at 46% for Ki67 <10%, 49% for Ki67 10%-20%, and 76% for Ki67 > 20%. The central Ki67 results tended to be higher than the local testing results. Central mRNA classifiers were developed for ER, PR, HER2 and Ki67 using Fluidigm Microfluidics Dynamic Arrays and correlate highly with central IHC assessment of these markers.

Conclusions: HR+ HER2- EBC is enriched for cancers with a low proliferative rate, a group of pts unlikely to benefit from the cell cycle-specific cytotoxic agent, capecitabine. Analyses of the impact of adjuvant X added to AC/T in EBC pts according to ER status, and according to Ki67 (analyzed as a binary and continuous variable) will be performed prior to SABCS, 2013.

Number of Patients% Ki67 Pos CellsTotal *HR+TNHER2+/HR+HER2+/ HR-0-104163622222711-151391066151016-20126871615821-3018411539201031-1005751403423555Total144081042510790*Totals do not equal sum of subtype categories due to missing HER2 information

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-09-01.

Analysis of Topoisomerase IIa and HER2 Status in 126 Patients from the US Oncology 9735 Trial of Adjuvant Chemotherapy with Docetaxel/Cyclophosphamide (TC) vs Doxorubicin/Cyclophosphamide (AC) in Early Breast Cancer

Background: HER2/neu (HER2) positive breast cancers are associated with worse survival, resistance to cyclophosphamide/methotrexate/fluorouracil, and hypothesized to be sensitive to anthracyclines. It has been postulated that only a subset of HER2 positive breast cancers are sensitive to anthracyclines. Investigators have been working on how to identify this subset of patients, thus sparing patients from anthracyclines that have potential cardiac and bone marrow toxicities. Overexpression of the topoisomerase IIa gene (TOP2A) is the putative biomarker for sensitivity to anthracyclines. Testing tumors for overexpression of this gene may help identify patients who will not benefit from anthracylines. TOP2A is located in the same amplicon as the HER2 gene and can be assessed for overexpression by a FISH assay.Materials and Methods: Paraffin tissue blocks were obtained in 126 patients entered on US Oncology trial 9735 which recruited patients between 1997 and 2000. Data on HER2 status and outcome was previously reported (JCO 27:1177-1183, 2009). TOP2A status was then assessed by fluorescent in situ hybridization (FISH) using the LSI TOP2A Spectrum Orange Probe (Vysis). A total of 20 cells were counted and a gene ratio of greater than 2.0 was considered positive. Clinical data and outcome were available for statistical analysis.Results: We found that none of the 97 HER2 negative cases demonstrated overexpression of TOP2A by FISH analysis. TOP2A was overexpressed in 43% of the 29 HER2 positive cases. An analysis of outcome will be presented at the meeting, although the number of cases limits this observation.Discussion: Our study supports the observation that TOP2A is not overexpressed in HER2 negative disease and is only observed in a subset of cancers overexpressing HER2. Clinical correlation of outcome will be necessary to confirm whether or not TOP2A is a reliable biomarker of sensitivity to anthracyclines. The ongoing US Oncology trial of TC vs. TAC in HER2 negative breast cancer (USOR Trial 06-090) should provide that evidence.Supported in part by a grant from sanofi-aventis.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2134.

Efficacy of BSI-201, a poly (ADP-ribose) polymerase-1 (PARP1) inhibitor, in combination with gemcitabine/carboplatin (G/C) in patients with metastatic triple-negative breast cancer (TNBC): Results of a randomized phase II trial

3

Background: TNBC is an aggressive breast cancer subtype that shares molecular and pathologic features with BRCA1-related breast cancers. BRCA-deficient cells are sensitive to inhibition of PARP1, a critical enzyme of cell proliferation and DNA repair, and thus represent a rational target of PARP inhibitor-based cancer therapy. The objectives of this study were to evaluate BSI-201, a potent PARP1 inhibitor, in combination with gemcitabine/carboplatin (G/C) in subjects with metastatic TNBC. Methods: Eligible subjects had measurable disease and had ≤2 prior cytotoxic regimens for ER-, PR-, and HER2-negative metastatic breast cancer. Patients were randomized (1:1) to G/C alone or G/C + BSI-201. Gemcitabine (1000 mg/m2) and carboplatin (AUC=2) were given on days 1 and 8, and BSI-201 (5.6 mg/kg; iv; biweekly) on days 1, 4, 8, and 11 every 21 days. Endpoints were clinical benefit rate (CBR = CR + PR + SD ≥6 months), progression-free survival (PFS) and overall survival (OS). Results: Analyses of the first 86 of a planned 120 patients showed that BSI-201 + G/C had improved CBR, median PFS, and median OS, compared with G/C alone. The frequency and nature of adverse events (AEs) did not differ between arms. Conclusions: This preliminary analysis demonstrates that BSI-201 + G/C significantly improves CBR, PFS, and OS, compared with G/C alone. BSI-201 + G/C was well tolerated, with BSI-201 adding no significant toxicity to G/C. Updated CBR, PFS, and OS for all 120 patients and exploratory correlative analyses of PARP expression and clinical response will be presented.

[Table: see text] [Table: see text]

First-line lapatinib combined with letrozole versus letrozole alone for hormone receptor positive (HR+) metastatic breast cancer (MBC): Subgroup analyses of borderline FISH+, IHC 2+, HER2 unknown (UNK), and treatment-naive (TN) populations from EGF30008

1062

Background: This double-blind, placebo-controlled, phase III trial assessed the benefit of adding lapatinib, an oral EGFR/HER2 tyrosine-kinase inhibitor, to letrozole alone in patients (pts) with HR+ MBC. The previously reported primary endpoint, investigator (INV) assessed PFS in HER2+ tumors, showed a significant benefit from dual therapy. Median PFS in the HR+ HER2+ population increased from 3 months (mo) in the letrozole/placebo group to 8.2 mo in the letrozole/lapatinib group [Hazard Ratio (95% CI)=0.71 (0.53,0.96), stratified log rank p = 0.019]. The HER-2-ve population did not derive benefit from the combination. Benefit from combined treatment was evaluated in a number of pre-planned exploratory subsets, including a noted trend in the HER2-ve population who progressed within 6 mo of receiving prior tamoxifen. Methods: 1286 pts were randomized to letrozole/lapatinib or letrozole/placebo. HER2 positivity was defined by a positive FISH ratio or by immunohistochemistry (IHC) 3+ in a central laboratory. INV assessed PFS in the sub-populations were analyzed using Kaplan-Meier with stratified log rank to compare treatment arms. These included tumor samples that were FISH borderline1.8–2.2 (n = 52), IHC 2+ (n = 215), HER2 status UNK (n = 115), and neo/adjuvant TN (n = 656). Results: INV assessed PFS demonstrated no significant prolongation for dual therapy for any of the exploratory populations [Hazard Ratio: (95%CI), p-value]; FISH 1.8–2.2 [1.03 (0.55, 1.95), p = 0.918]; IHC 2+ [1.13 (0.82, 1.57), p = 0.441]; HER2 UNK [0.71 (0.45,1.11), p = 0.126]; TN [0.88 (0.73, 1.07), [p = 0.199]. Conclusions: The combination of letrozole and lapatinib did not significantly improve PFS in any of the pts with lower levels of HER2 expression (borderline FISH, IHC 2+, or HER2 UNK) or in TN pts. These data confirm the HER2-ve result previously reported and substantiate that only tumors with the target benefit from the addition of a targeted therapy.

[Table: see text]

Cardiac safety of the lapatinib/letrozole combination as first-line therapy in patients (pts) with metastatic breast cancer (MBC)

1095

Background: Cardiotoxicity of traztuzumab therapy increases in pts pretreated with anthracyclines (A), radiotherapy to left breast, hypertension, or low baseline ejection fraction (EF). We report the cardiac safety profile of lapatinib, an oral, dual EGFR/HER-2 tyrosine kinase inhibitor, in a chemotherapy naïve or A-exposed pts with MBC. Methods: Women (n = 1286) with endocrine sensitive, previously untreated MBC received lapatinib and letrozole (L+L) or letrozole and placebo (L+P): 33% received previous A; 48% previous tamoxifen; <1% previous trastuzumab (T); <2% previous aromatase inhibitor. EF was evaluated by MUGA or echocardiogram at baseline, every 8 wk and at study withdrawal. Rate of cardiac events (NCI CTCAE grading), median time to onset, and duration of EF depression were assessed. Results: Cardiac events (CE; MEDRA terms: ejection fraction decreased, left ventricular dysfunction, ventricular dysfunction and cardiac failure) were infrequent in both arms. Grade 3/4 and 1/2 CE were reported in 0.9% and 4.0% of pts, respectively, in the L+L arm, and in 0.3% and 2.1%, respectively, in the L+P arm. The only symptomatic CE was a grade 4 event in the L+L arm. There was no apparent relationship between previous A exposure and CE frequency and severity. Median L exposure was 40 wk on L+L, 38 wk on L+P. Median time to onset and duration of EF decrease were 21.8 and 8.1 wk, respectively, on L+L, and 34.6 and 5.4 wk, respectively on L+ P. On the L+L arm, the dose was adjusted/interupted for 8 CE cases, discontinued for 6, and unchanged for 22. On the L+P arm, interuption of L was reported for 2 CE cases, discontinuation for 5, and in 7 CE events there was no change in therapy. Eight CE on L+L and 1 CE on L+P had not resolved as of the last report. Conclusions: This is the first long-term evaluation of lapatinib cardiac signals in a controlled trial in a trastuzumab-naïve MBC pt population. The frequency of cardiac events and degree of absolute EF decrease was low and occurred at similar rates in pts with or without anthracycline exposure. These encouraging cardiac safety data in first line metastatic BC study are promising for the ongoing study of lapatinib in patients with early HER-2+ BC treated on ALTTO trial.

[Table: see text]

Efficacy of BSI-201, a poly (ADP-ribose) polymerase-1 (PARP1) inhibitor, in combination with gemcitabine/carboplatin (G/C) in patients with metastatic triple-negative breast cancer (TNBC): Results of a randomized phase II trial

3

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]

Quantitative assessment of HER2 status and correlation with efficacy for patients (pts) with metastatic breast cancer (MBC) in a phase II study of trastuzumab-DM1 (T-DM1)

1003

Background: The antibody-drug conjugate T-DM1 combines the biological activity of trastuzumab with targeted delivery of an anti-microtubule agent (DM1) to HER-2-expressing cancer cells. This analysis examines correlation of response to T-DM1 with HER-2 status, as assessed by fluorescent in situ hybridization (FISH), immunohistochemistry (IHC), mRNA quantitative real-time polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA) (HER-2 extracellular domain [ECD]), for pts enrolled in TDM4258g, a phase II study of T-DM1 in pts with MBC. Methods: TDM4258g is an open-label, single-arm study of T-DM1 administered at 3.6 mg/kg IV q3w. Pts had progressed on HER-2-directed therapy and received chemotherapy in the metastatic setting and were HER-2 + based on local testing. Archival tissue (paraffin block or >7 unstained tumor slides) was collected for retrospective central laboratory testing. HER-2 DNA amplification was determined by FISH, and protein levels by IHC. qRT-PCR for HER-2 was performed on extracted RNA; baseline HER-2 ECD ELISA was performed on pt sera. HER-2 data for each pt were compared with pt's best response. Results: As of August 29, 2008, 112 pts had enrolled; 107 were efficacy-evaluable pts with median 4.4 mos follow-up. There were 42/107 (39.3%) partial responses (PR) (investigator assessment). Of 86 pts centrally tested, 64 (74.4%) were confirmed HER-2+ (FISH+ and/or IHC 3+), with 32/64 (50%) PR. Of 76 pts tested by both FISH and IHC, 15/76 (19.7%) were confirmed HER-2- (FISH- and IHC 2+/1/0), with 2/15 (13.3%) PR. In HER-2+ pts, response rates did not correlate with high versus low FISH+ counts, nor with HER-2 ECD levels. Among 39 HER-2+ (FISH+ and/or IHC3+) efficacy-evaluable pts with qRT-PCR data, there were 13/19 (68.4%) PR for pts with qRT-PCR above median levels, and 7/20 (35.0%) PR for pts with qRT-PCR below median. Conclusions: HER-2+ pts (by central retesting) had better responses to T-DM1 than HER-2- pts, although a small number of PR were observed in HER-2- pts. Assessment of HER-2 expression by qRT-PCR may identify pts more likely to respond to T-DM1 therapy. Updated data, including additional diagnostic markers, will be presented at the meeting.

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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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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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Double-blind, randomized trial comparing the efficacy and tolerability of fulvestrant versus anastrozole in postmenopausal women with advanced breast cancer progressing on prior endocrine therapy: results of a North American trial

PURPOSE

To compare the efficacy and tolerability of fulvestrant (formerly ICI 182,780) with anastrozole in the treatment of advanced breast cancer in patients whose disease progresses on prior endocrine treatment.

PATIENTS AND METHODS

In this double-blind, double-dummy, parallel-group study, postmenopausal patients were randomized to receive either an intramuscular injection of fulvestrant 250 mg once monthly or a daily oral dose of anastrozole 1 mg. The primary end point was time to progression (TTP). Secondary end points included objective response (OR) rate, duration of response (DOR), and tolerability.

RESULTS

Patients (n = 400) were followed for a median period of 16.8 months. Fulvestrant was as effective as anastrozole in terms of TTP (hazard ratio, 0.92; 95.14% confidence interval [CI], 0.74 to 1.14; P =.43); median TTP was 5.4 months with fulvestrant and 3.4 months with anastrozole. OR rates were 17.5% with both treatments. Clinical benefit rates (complete response + partial response + stable disease > or = 24 weeks) were 42.2% for fulvestrant and 36.1% for anastrozole (95% CI, -4.00% to 16.41%; P =.26). In responding patients, median DOR (from randomization to progression) was 19.0 months for fulvestrant and 10.8 months for anastrozole. Using all patients, DOR was significantly greater for fulvestrant compared with anastrozole; the ratio of average response durations was 1.35 (95% CI, 1.10 to 1.67; P < 0.01). Both treatments were well tolerated.

CONCLUSION

Fulvestrant was at least as effective as anastrozole, with efficacy end points slightly favoring fulvestrant. Fulvestrant represents an additional treatment option for postmenopausal women with advanced breast cancer whose disease progresses on tamoxifen therapy.

Low proliferative rate of invasive node-negative breast cancer predicts for a favorable outcome: a prospective evaluation of 669 patients

This study was designed to compare outcome in terms of disease-free survival (DFS) in women with histologically negative axillary lymph nodes and documented low proliferative rate cancer to other well-defined prognostic factors including type of adjuvant treatment. Between 1988 and 1998, we studied 669 patients with invasive node-negative breast cancer up to 5 cm in size and low proliferative rate measured by flow cytometry to determine S-phase fraction (SPF) or by histochemistry (Ki67/MIB1). At a median follow-up of 53 months, 5-year DFS for the entire group was 94% and did not differ significantly by type of systemic adjuvant treatment: none (133 patients, 95% DFS), tamoxifen (441 patients, 94% DFS), or chemotherapy with doxorubicin and cyclophosphamide (95 patients, 92% DFS). In a multivariate prognostic factor analysis, only tumor size was significant; 5-year DFS was 96% for T1N0 cancer versus 89% for T2N0 cancer (P = 0.01). We have prospectively confirmed that a low rate of proliferation as measured by SPF or MIB1 determination confers an excellent prognosis in invasive node-negative breast cancer up to 5 cm in size, regardless of adjuvant treatment.

Induction of TGF-beta1 by the matricellular protein SPARC in a rat model of glomerulonephritis

Induction of TGF-beta1 by the matricellular protein SPARC in a rat model of glomerulonephritis.

BACKGROUND

SPARC has been implicated as a counteradhesive and antiproliferative protein associated with deposits of extracellular matrix in renal disease.

METHOD

We have examined the effect of recombinant SPARC containing a C-terminal His tag (rSPARC) in an acute model of mesangial cell injury that is induced in the rat by an antibody against the Thy1 antigen on the mesangial cell membrane. The recombinant protein was administered 24 hours after the induction of nephritis and was infused through day 4.

RESULTS

rSPARC was localized to the renal glomeruli of rats treated with anti-Thy1 antibody. Type I collagen and fibronectin, as well as transforming growth factor-beta1 (TGF-beta1), were increased at day 5 in rats treated with rSPARC (N = 4, P < 0.05 vs. delivery buffer), but only minimal effects were seen on mesangial cell and endothelial cell proliferation. In primary cultures of rat mesangial cells, infusion of rSPARC was associated with increases in TGF-beta1 mRNA and in total, secreted TGF-beta1 protein.

CONCLUSIONS

rSPARC stimulates expression of TGF-beta1 both in vitro and in vivo. Given the closely regulated expression of SPARC, TGF-beta1, and type I collagen in several animal models of glomerulonephritis, we propose that SPARC could be one of the major mediators of the induction of TGF-beta1 in renal disease.

Phase I trial of interferon gamma retroviral vector administered intratumorally with multiple courses in patients with metastatic melanoma

The purpose of this study was to determine the safety and antitumor activity of IFN-gamma retroviral vector in patients with advanced melanoma. Seventeen patients (9 single courses, 8 multiple courses) received a total of 363 intratumor injections of IFN-gamma retroviral vector (1 x 10(7) PFU/ml administered at 0.3, 0.5, and 1.0 ml per cohort). No grade III/IV adverse events were attributed to study medication. Replication-competent retrovirus was not detected in any of the 17 patients by polymerase chain reaction studies. Eight patients showed elevated anti-tumor antibody responses in comparison with baseline by ELISA. One of nine patients treated with a single course had an optimal response of stable disease, compared with eight of eight multiple-injected patients. Median survival of single-injected patients was 150 days, and patients who received multiple injections have still not achieved median survival duration, with four of eight still living (p = 0.0462, Wilcoxon; p = 0.0273, log rank). We conclude that intratumor injection of IFN-gamma is safe and well tolerated. Evidence of antitumor activity is suggested in patients with advanced malignancy that received multiple injections.