The pattern of metastatic spread among breast cancer sub-types

Abstract #2025

Background: Although breast cancer subtypes are associated with differing relapse risks, the patterns of metastatic spread are less well defined, particularly for more than the first site of metastasis. We describe the sites of all diagnosed metastases among breast cancer subtypes in a large series of women diagnosed with breast cancer to further define patterns of spread.
 Methods: Subjects with early stage breast cancer referred to the British Columbia Cancer Agency from 1986 to 1992 were included. Archival paraffin tissue blocks were used to construct a tissue microarray. Breast cancer subtypes were defined as Luminal A (ER/PR+ and HER2- and Ki67 <19%), Luminal B (ER/PR+, and HER2- and Ki67 >19%), LuminalHer2 (Her2+ and ER/PR+), HER2 (HER2+ and ER- and PR-), and Basal (HER2-ER-PR- and CK 5/6+and/orEGFR+). All documented sites of distant metastasis were abstracted by chart review according to predefined categories.
 Results: 3526 eligible women were classified according to Luminal A (2109), Luminal B (514), LuminalHER2 (252), HER2 (276) and Basal (375) and 30%,47%, 48%, 50% and 42% in each subgroup were diagnosed with distant metastasis. Median Survival with metastatic disease was 2.2, 1.6 and 1.3 years in Luminal A, B and LuminalHER2 groups and 0.7 and 0.5 years in the HER2 and Basal types, respectively. Bone was the predominant site of metastasis for luminal groups A (76%), B (73%) and LuminalHER2 (70%). The distribution was more heterogeneous in HER and Basal groups. High rates of brain metastasis were observed in the HER2 (30%) and Basal (27%) and less frequently in the LuminalHER2 (17%) and other groups (p <0001).
 
 Conclusion: Molecular breast cancer subtypes are associated with specific distributions of metastasis which may lead to specific prophylactic therapies to modify this risk. New systemic therapies, including trastuzumab, may impact these patterns and survival after recurrence.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2025.

A new enrichment model for high sensitivity detection and downstream analyses of circulating tumor cells in breast cancer patients

Abstract #4162

The detection of circulating tumor cells (CTCs) in breast cancer patients have the potential to improve prognostication and the monitoring of response to treatment. Most CTC enrichment technologies are based on binding to anti-EpCAM antibodies. The sensitivity of such assays is limited by tumors that express no or undetectable levels of EpCAM. Improvements in CTC detection coupled with the development of systems to interrogate CTCs for therapeutic target expression could lead to novel applications for patient monitoring, clinical diagnosis and treatment. In this study, we describe a sensitive and reproducible enrichment method for CTCs. We defined cells as circulating tumor cells with three criteria: Positive for cytokeratin (CK+) and DAPI (nuclear) (DAPI+) and negative staining for CD45 (CD45-). We have previously reported that this system has a higher sensitivity for circulating tumor cell detection and provides a better platform for CTC downstream analyses compare to the methods currently available in the market. Herein, we describe the use of this platform for the evaluation of breast cancer biomarkers in CTCs. Blood samples from patients with metastatic breast cancer were used for CellSearch™ assay (Veridex , LLC ) and our CTC assay (A1000 CTC enrichment and detection kit, Genetix). We performed the CTC enrichment assay using the combination of anti-CK and anti-EpCAM antibodies. CTCs were identified with brightfield and fluorescence labeled anti-CK, anti-CD45 and DAPI (nuclear stain) images. The Ariol® system (Applied Imaging Corporation) was employed for automated cell image capture and analysis of CTCs on glass slides. CTCs enriched on the glass slides were used for CTC downstream analysis. Our CTC enrichment model is designed to have the capability to enrich all the three types of CTCs including CK+ & EpCAM+, CK+ & EpCAM-/low and CK-/low & EpCAM+ cells. Compared to the enrichment methods using anti-EpCAM or anti-cytokeratin antibody alone, a higher CTC detection rate and a larger dynamic CTC detected range were obtained with our new enrichment model. Interestingly there were clear CTC number differences with enrichment methods in the higher CTC count patient samples which indicate that the different enrichment methods may enrich different types of CTCs from patient blood samples.
 Results of DNA and RNA FISH analyses on enriched CTCs indicate that the CTCs on glass slides can be used for its downstream analyses directly or indirectly. Our method may have better performance on enrichment of heterogeneous CTCs and provide a better platform for CTCs profiling for biomarker evaluations and CTC downstream analyses.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4162.

Decline in pulmonary function in patients with breast cancer receiving dose-dense chemotherapy: a prospective study

BACKGROUND

Prompted by complaints of dyspnea in breast cancer patients receiving adjuvant dose-dense chemotherapy (DDC), we sought to evaluate the possible association of DDC with pulmonary dysfunction.

PATIENTS AND METHODS

A total of 34 consecutive patients receiving adjuvant DDC were enrolled. The chemotherapy regimen consisted of i.v. doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) (AC) every 14 days x4 with growth factor support followed by weekly i.v. paclitaxel 80 mg/m(2) x12. The following parameters were prospectively measured before and after the AC protocol (P1, P2) and at completion of paclitaxel treatment (P3): presence of dyspnea, blood pressure, pulse rate, hemoglobin, erythrocyte sedimentation rate, C-reactive protein level, cardiac ejection fraction, and pulmonary function. Repeated measures analysis was used to evaluate differences among the time points, and paired t-test was used to evaluate differences between consecutive time points.

RESULTS

Although only five patients (15%) complained of dyspnea, there was a significant decrease in mean carbon monoxide diffusing capacity (DLCO), in all patients from P1 (22.09 ml/min/mmHg) to P3 (15 ml/min/mmHg) and in 29 of 32 patients (90.6%) from P1 to P2 (15.96 ml/min/mmHg) (P<0.001).

CONCLUSIONS

DDC is associated with a statistical significant reduction in DLCO. Awareness of this potential toxicity may be important in women with preexisting lung disease.

Prescribing extended adjuvant letrozole

The efficacy of 5 years of adjuvant tamoxifen in preventing disease recurrence in patients with breast cancer has been well established. Once patients have completed tamoxifen therapy, however, recurrence risk remains but treatment options are limited. Aromatase inhibitors such as letrozole are emerging as potential alternatives to tamoxifen therapy and as an option after tamoxifen. The pioneering MA-17 trial was designed to evaluate the efficacy and safety of letrozole in the extended adjuvant setting in postmenopausal women who remained disease-free after about 5 years of tamoxifen. The trial was unblinded at first interim analysis after letrozole proved more effective than placebo in improving disease-free survival. As such, the optimal duration of extended adjuvant letrozole was left in question. However, recent results from cohort analysis in MA-17 have shown an ongoing and increasing benefit of letrozole for up to 4 years after tamoxifen, suggesting that longer periods of extended adjuvant letrozole are safe and clinically beneficial.

Objective response rate in a phase II multicenter trial of pertuzumab (P), a HER2 dimerization inhibiting monoclonal antibody, in combination with trastuzumab (T) in patients (pts) with HER2-positive metastatic breast cancer (MBC) which has progressed during treatment with T

1004

Background: T and P bind to different epitopes on the extra cellular domain of HER2. Unlike T, P binds to the dimerization domain and blocks homo- and hetero-dimerization of HER2 with other HER kinase family members. Xenograft models support the hypothesis that the complementary mechanisms of action could result in augmented efficacy when T and P are combined. Methods: Two-stage design, criteria to proceed to the 2nd stage were: ≥ 2 partial responses (PR) or 1 PR and 12 stable disease (SDs) or 13 SDs. Eligibility included: measurable, centrally-tested HER2 positive breast cancer; up to 3 lines of prior chemotherapy plus T (including adjuvant chemotherapy plus T); disease progression during T as most recent treatment for metastatic disease; baseline left ventricular ejection fraction (LVEF) ≥ 55% and no decrease of LVEF to below 50% during prior T treatment. Consenting Pts received T i.v. weekly or every 3 weeks at 2 mg/kg or 6 mg/kg respectively (with re-loading dose if required) plus 420mg fixed dose of P i.v. every 3 weeks following loading dose 840mg. Study treatment was initiated within 9 weeks of the last dose of T given as most recent therapy. An independent data safety monitoring board has overseen the 1st stage safety data. Results: Recruitment into 1st stage is complete. The main adverse events were diarrhea (71%), fatigue (46%), nausea/vomiting (38%) and rash (25%). Most AE’s were mild to moderate (there was 1 case of Grade 3 diarrhea) and none was treatment-limiting. There were no clinical cardiac events, and central review revealed no case of fall in LVEF of ≥10% and to ≤50%. Response status: 5 confirmed PR (21%); 12 SD (50%). Responses have been observed in lymph node and liver metastases. Recruitment into the 2nd stage of the trial has commenced. Conclusions: The combination of the P and T is active and well tolerated in patients with pre-treated HER2 positive breast cancer which has progressed during treatment with T.

No significant financial relationships to disclose.

Identifying patients at high risk for neutropenic complications during chemotherapy for metastatic breast cancer (MBC) with doxorubicin or pegylated liposomal doxorubicin: Development of a prediction model

6598

Background: Despite the effectiveness of anthracycline (ACH) therapy in the adjuvant and MBC settings, neutropenic complications (NC) remain a common and often unpredictable problem. Consequences may include dose reductions or delays in chemotherapy, or hospitalization for fever or infection. This study describes the development of a cycle-based risk prediction model for NC during chemotherapy with traditional doxorubicin (DOX) or a pegylated liposomal formulation (PLD) for MBC. Methods: Data analyzed was from a randomized clinical trial of MBC patients (n=509), who received chemotherapy with DOX (60 mg/m2 every 3 wks) or PLD (50 mg/m2 every 4 wks) [O'Brien, 2004]. NC were defined as an absolute neutrophil count (ANC) = 1.5 x106 cells/L, febrile neutropenia or neutropenia with infection. Patient, treatment and hematological factors potentially associated with NC were evaluated. Factors with a p-value of ≤ 0.25 within a cycle were included in a generalized estimating equations (GEE) regression model. Using backward elimination, we derived a risk scoring algorithm (range 0–63) from the final reduced model. Results: Risk factors retained in the model included poor performance status, ANC = 2.0 × 106 cells/L at some point in the previous cycle, the first cycle of chemotherapy, DOX vs. PLD and older age. A precycle risk score from = 25 to < 40 for a given patient was identified as being the optimal threshold for sensitivity (58.0%) and specificity (78.7%). Patients with a score at or beyond this threshold would be considered at high risk for developing NC in later cycles. Risk scores below, within, or above this threshold predict a 0.3%–2%, 3%–8% and a 9%–45% probability risk of NC, respectively. Conclusion: This risk prediction tool demonstrated acceptable internal validity and can be readily applied by the clinician prior to a given cycle of chemotherapy. The application of this prediction tool may allow for identification and targeted intervention (such as growth factor support or the use of PLD) for those most likely to experience NC during anthracycline-based chemotherapy for MBC.

No significant financial relationships to disclose.

Ratiometric dosing of irinotecan (IRI) and floxuridine (FLOX) in a phase I trial: A new approach for enhancing the activity of combination chemotherapy

2549

Background: Like many pairs of chemotherapy agents, the combination of IRI and FLOX displays ratio-dependent activity in vitro. CPX-1, a liposome formulation of IRI:FLOX, was developed to maintain a synergistic 1:1 molar ratio in vivo, was highly active in preclinical models, and was evaluated in a phase 1 trial (CLTR0104–101). Methods: Doses were escalated from 30U/m2 (1U= 1 mg IRI + 0.36 mg FLOX) to 270 U/m2 given on day 1 and 15 of each 28 day cycle. Adult patients (pts) with advanced solid tumors, ECOG PS<2, adequate bone marrow, liver, and renal function were eligible; 4 pts per cohort. After defining the MTD, additional pts with CRC were enrolled (extension phase). IRI completed greater than 12 months prior to this trial was allowed in the absence of resistance to IRI. PK was done on day 1 and 15 of the 1st cycle. Results: Safety: The dose escalation phase enrolled 24 pts in 6 cohorts and added 2 pts in the 5th cohort (210U/m2; the MTD) after noting dose limiting diarrhea (3 pts) and neutropenia (1 pt) including one death from dehydration and renal failure due to prolonged diarrhea (gr3) & vomiting (gr2) at 270U/m2. An additional 7 pts with CRC received 210U/m2 in the extension phase. Grade 3/4 adverse events included diarrhea, nausea, vomiting, neutropenia and thrombocytopenia with most occurring at 270U/m2. No new toxicities were observed for this combination. Response: 30/33 pts were evaluable with 2 confirmed PRs (NSCLC and CRC), 21 SD and 7 PD. Median PFS was 5.4 mos. (0.3–11.8 mos.) in 15 pts w/CRC. PK: All pts maintained synergistic plasma IRI:FLOX ratios for 24h. IRI and FLOX AUCs (0-inf) were greater for CPX-1 than expected for conventional drugs. AUCs for SN-38 and 5FU at 210U/m2 were 0.8 ± 0.1 and 10 ± 8.7 μg-hr/mL, respectively, indicating bioavailability for both drugs. Conclusion: CPX-1 was well tolerated in the outpatient setting and evidence of anti-tumor activity was obtained. This is the first clinical evaluation of ratiometric dosing in which a synergistic drug ratio, pre-selected in vitro based on optimal anti-tumor activity, was maintained systemically to enhance therapeutic benefit.

[Table: see text]

Identification of cancer care and protocol characteristics associated with recruitment rate in breast cancer clinical trials in Ontario

17042

Background: Recruitment rate (RR) in clinical trials (CT) has been recognized to be low. Poor accrual may lead to premature closing of CT or decrease of the planned power to detect an effect if present. Methods: Objectives were primarily to identify characteristics of cancer care settings and clinical trials protocols associated with low RR and secondarily (1) to determine the RR and (2) to compare the RR between years. A cross-sectional design was used. Poisson regression was used for multivariate analysis. RR was calculated by CT, hospital and year in Ontario between 1997 and 2002. Number of patients recruited in each CT was obtained from cooperative groups and pharmaceutical companies. Number of patients with breast cancer (BC) was obtained from the Ontario Cancer Registry. Prevalence of women with metastatic BC was calculated from the British Columbia Breast Cancer Outcome Unit database. Characteristics of cancer care and protocols were collected. Results: Response rates were 84% (66/79) for hospitals, 69% (9/13) for cooperative groups and 80% (8/10) for pharmaceutical companies. Recruitment rates varied between 1.3% and 5.5% (median, p=0.0003). Characteristics of cancer care were not associated with RR (number of oncologists, breast oncologists, breast surgeons, investigators, clinical research associates and being a cancer centre or an academic centre). Among protocol characteristics, the following were associated with RR in univariate analysis: phase, randomization, type of intervention, placebo, extent of the trials (local vs. national vs. international), number of sites, population (adjuvant vs. metastatic), menopausal status, premature closing of the trial, time frame for enrolment, extra baseline and follow-up testing. In multivariate analysis, type of control arm and time frame for enrolment were significant. CT using placebo compared to an active control arm were less likely to recruit patients (relative risk 0.57, p=0.0144). CT with a time frame for enrolment greater than 9 weeks were more likely to enrol patients (relative risk 1.43, p=0.0020). Conclusions: RR is very low. No easily modifiable factors have been identified. This project was funded by the Canadian Breast Cancer Foundation, Ontario Chapter.

[Table: see text]

A phase I dose escalation pharmacokinetic (PK) and pharmacodynamic (PD) study of weekly and twice weekly erlotinib in advanced stage solid malignancies

3594

Background: Erlotinib is a potent oral TKI of the epidermal growth factor receptor (EGFR). At the current recommended daily dose of 150 mg/day there is activity in advanced stage NSCLC, but with frequent grade 1/2 rash and diarrhea. We performed a phase I dose escalation study of erlotinib with a once and twice weekly schedule to assess the PKs, PDs, and to determine if toxicities would be less on an intermittent but high dose schedule. Methods: A standard dose escalation schedule starting at 1,400 mg once/week and 600 mg twice/week with increments of 200 mg to 4 dose cohorts/schedule was utilized with three patients per cohort. A cycle consisted of 3 weeks of therapy. PKs were performed on cycle 1 and 2. PDs on normal skin punch biopsies were performed at baseline and after cycle 1. Tumour evaluation was done following every 2nd cycle. Subjects were treated until progression or unacceptable toxicity. Results: 32 patients were enrolled from Oct 2004-April 2006. Median age 58 years (28–74 years); median PS 1 (0–2); and median prior palliative systemic regimens 2 (0–6). In the once weekly schedule the maximum tolerated dose (MTD) was not reached with the top dose of 2,000 mg/week. A median of 2 cycles were delivered (1–14), with 3/13 patients achieving stable disease = 3 months. 4/13 patients had G1 rash and 6/13 patients G1 diarrhea during the first 2 cycles. In the twice weekly schedule the MTD was reached at 1,200 mg twice/week with 2/6 subjects experiencing G3 rash. The recommended dose level is 1,000 mg twice/week. A median of 4 cycles were delivered (1–28) with 2 partial responses, 1 minor response and 6 stable disease = 3 months out of 19 patients in total. G1/2 rash or diarrhea occurred in 13 and 9 patients respectively. No corneal toxicity was seen. The PK data demonstrated a variable but linear pattern. At 1,000 mg twice/week the median Cmax, Tmax and AUC0–24 hr was 6.28 μg/ml, 2 hours and 135 μg.h/ml respectively. PD analysis is ongoing. Conclusions: A once weekly and twice weekly high dose schedule of erlotinib is feasible, with MTD not reached in the once weekly schedule. A recommended dose of 1,000 mg twice/week has clinical activity, is generally well tolerated, and results in significantly higher systemic exposure than the 150 mg once daily dose.

No significant financial relationships to disclose.

Phase 1 study of CPX-1, a fixed ratio formulation of irinotecan (IRI) and floxuridine (FLOX), in patients with advanced solid tumors

2014

Background: In vitro studies have shown that varying the ratio of individual agents in drug combinations can result in synergistic, additive or antagonistic activity against tumor cells. CPX-1 is a liposomal formulation of IRI and FLOX in a fixed 1:1 molar ratio which was selected as optimal in vitro and confirmed to be synergistic in vivo in preclinical tumor models. CPX-1 overcomes the dissimilar pharmacokinetics (PK) of the individual drugs, enables sustained maintenance of this ratio after IV administration, and was evaluated in a Phase I open-label, dose-escalation study. Methods: Starting dose was 30 U/m2 (1 Unit of CPX-1 contains 1 mg IRI + 0.36 mg FLOX) given on day 1 and 15 of each 28-day cycle. Dose escalation was by modified Fibonacci with 4 subjects/cohort. Eligibility included: ≥ 18 yo; advanced solid tumor; ECOG PS ≤ 2; adequate bone marrow/liver/renal function. PK analysis was done on day 1 and 15 of the first cycle. Results: 26 subjects (16M:10F), median age 54.5 y (21–72), all with prior therapy, enrolled in 6 cohorts with the 5th cohort expanded to 6 subjects. Diagnoses: 8 colorectal, 3 pancreatic, 3 ovarian, 2 breast, 2 gastric, 2 esophageal, 2 sarcomas, 1 renal cell, 1 prostate, 1 NSCLC and 1 sphenoid sinus. Response: 20 subjects evaluable: 2 confirmed PRs (NSCLC 8+ wks; Colon 13+ wks, in a patient with prior IRI exposure) and 13 with SD (8–24+wks). Safety: DLTs were observed at the 6th dose level: 4 subjects with DLTs: 3 diarrhea (one resulting in death due to dehydration/ARF) and one neutropenia. Other possibly related grade 3 and 4 events included one each of: grade 3 diarrhea, grade 3 vomiting, grade 3 neutropenia, grade 3 fatigue, grade 3 compression fracture and arthralgia and pulmonary embolism grade 4. PK: In all 14 subjects analyzed to date the 1:1 molar ratio of IRI to FLOX was maintained for 24 hours and metabolites 5-FU and SN-38 were present in the plasma. Conclusions: CPX-1 represents a new approach to developing drug combinations in which drug ratios are pre-selected in vitro based on optimal antitumor activity and maintained systemically through pharmacokinetic control. Phase 2 studies are planned with a recommended dose of 210U/m2 of CPX-1.

[Table: see text]

A phase 1 study of OSI-211 given as an intravenous infusion days 1, 2, and 3 every three weeks in patients with solid cancers

PURPOSE

To define the maximum tolerated dose (MTD), recommended phase II dose (RD) and dose limiting toxicity (DLT) of liposomal lurtotecan, OSI-211 (formerly known as NX211), given as a short intravenous infusion on days 1, 2, and 3 every three weeks.

EXPERIMENTAL DESIGN

Thirty-seven patients were enrolled and treated in a dose escalation study from a starting dose of 0.15 mg/m(2) daily x 3 to 2.1 mg/m(2) daily x 3. Detailed pharmacokinetic analyses of blood were done on both days 1 and 3 of the first cycle and toxicity was monitored.

RESULTS

Two MTDs were defined; one for patients defined as minimally pretreated and one for those heavily pretreated. Dose limiting toxicity was myelosuppression: primarily thrombocytopenia although neutropenia was also noted. The MTD was 2.1 mg/m(2)/d (total dose of 6.3 mg/m(2)) in minimally pretreated patients and 1.8 mg/m(2)/d (5.4 mg/m(2) total dose) in heavily pretreated patients. Pharmacokinetics revealed that AUC and C (max) increased with dose and were significantly higher than that of free lurtotecan (AUC approx. 100 fold higher). The half life and duration of the active lactone form were also significantly longer than historical data on free drug. Two partial responses were seen, one each in a patient with breast and ovarian cancer.

CONCLUSIONS

Two Phase II recommended doses were established for OSI-211 given as a daily x 3 schedule every three weeks. The recommended phase II dose is 1.8 mg/m(2) daily x 3 for minimally pretreated patients and 1.5 mg/m(2) for those heavily pretreated. Phase II studies should be initiated in sensitive tumours.

A phase I study of OSI-211 and cisplatin as intravenous infusions given on days 1, 2 and 3 every 3 weeks in patients with solid cancers

BACKGROUND

OSI-211 (also known as NX211) is a liposomal preparation of the topoisomerase I inhibitor, lurtotecan, which has shown antitumor activity in phase I and II clinical trials. Cisplatin is a widely used antineoplastic agent with activity in a broad range of tumor types. This phase I trial was conducted to determine the recommended doses of these agents, and their pharmacokinetic properties and toxicities in patients with advanced solid malignancies.

PATIENTS AND METHODS

Fourteen patients with advanced and/or metastatic solid malignancies were enrolled in this trial. The first planned dose level was OSI-211 0.9 mg/m(2) with cisplatin 25 mg/m(2) administered intravenously daily for the first three consecutive days of a 21-day cycle. Patients were evaluated for hematological and non-hematological toxicities, and pharmacokinetic studies were performed on both agents.

RESULTS

The recommended phase II dose was determined to be 0.7 mg/m(2) OSI-211 given with 25 mg/m(2) cisplatin. Dose-limiting neutropenia was seen in two of three patients at the starting dose level. Three of 11 patients at the second (lower) dose level experienced dose-limiting thrombocytopenia; febrile neutropenia was also seen in one patient. Non-hematological toxicities were generally manageable and included fatigue, nausea and vomiting. Considerable variability was seen in both hematological toxicities and pharmacokinetics. One complete response and three partial responses were seen.

CONCLUSIONS

The recommended phase II dose for this combination is 0.7 mg/m(2) OSI-211 with 25 mg/m(2) cisplatin given as an intravenous infusion on days 1, 2 and 3 of a 21-day cycle. The main toxicity was myelosuppression. Preliminary evidence of antitumor activity was seen.