Lasofoxifene versus fulvestrant for ER+/HER2- metastatic breast cancer with an ESR1 mutation: results from the randomized, phase II ELAINE 1 trial

BACKGROUND

Acquired estrogen receptor alpha (ER/ESR1) mutations commonly cause endocrine resistance in ER+ metastatic breast cancer (mBC). Lasofoxifene, a novel selective ER modulator, stabilizes an antagonist conformation of wild-type and ESR1-mutated ER-ligand binding domains, and has antitumor activity in ESR1-mutated xenografts.

PATIENTS AND METHODS

In this open-label, randomized, phase II, multicenter, ELAINE 1 study (NCT03781063), we randomized women with ESR1-mutated, ER+/human epidermal growth factor receptor 2 negative (HER2-) mBC that had progressed on an aromatase inhibitor (AI) plus a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) to oral lasofoxifene 5 mg daily or IM fulvestrant 500 mg (days 1, 15, and 29, and then every 4 weeks) until disease progression/toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were safety/tolerability.

RESULTS

A total of 103 patients received lasofoxifene (n = 52) or fulvestrant (n = 51). The most current efficacy analysis showed that lasofoxifene did not significantly prolong median PFS compared with fulvestrant: 24.2 weeks (∼5.6 months) versus 16.2 weeks (∼3.7 months; P = 0.138); hazard ratio 0.699 (95% confidence interval 0.434-1.125). However, PFS and other clinical endpoints numerically favored lasofoxifene: clinical benefit rate (36.5% versus 21.6%; P = 0.117), objective response rate [13.2% (including a complete response in one lasofoxifene-treated patient) versus 2.9%; P = 0.124], and 6-month (53.4% versus 37.9%) and 12-month (30.7% versus 14.1%) PFS rates. Most common treatment-emergent adverse events with lasofoxifene were nausea, fatigue, arthralgia, and hot flushes. One death occurred in the fulvestrant arm. Circulating tumor DNA ESR1 mutant allele fraction (MAF) decreased from baseline to week 8 in 82.9% of evaluable lasofoxifene-treated versus 61.5% of fulvestrant-treated patients.

CONCLUSIONS

Lasofoxifene demonstrated encouraging antitumor activity versus fulvestrant and was well tolerated in patients with ESR1-mutated, endocrine-resistant mBC following progression on AI plus CDK4/6i. Consistent with target engagement, lasofoxifene reduced ESR1 MAF, and to a greater extent than fulvestrant. Lasofoxifene may be a promising targeted treatment for patients with ESR1-mutated mBC and warrants further investigation.

Abstract OT1-01-02: An open-label, randomized, multi-center phase 2 study evaluating the activity of lasofoxifene relative to fulvestrant for the treatment of postmenopausal women with locally advanced or metastatic ER+/HER2 - breast cancer (MBC) with an ESR1 mutation

Endocrine based therapy is the standard treatment for estrogen receptor positive (ER+) MBC. Agents targeting the ER pathway including aromatase inhibitors (AIs), fulvestrant and tamoxifen along with CDK 4/6 inhibitors are considered standard for first and 2nd line treatment. However, endocrine resistance develops in nearly all patients and the optimal systemic therapy after progression on a CDK 4/6 inhibitor is unknown.

Lasofoxifene is a third generation SERM previously investigated for the treatment of osteoporosis and vulvo-vaginal atrophy (VVA). In a large phase 3 trial evaluating the efficacy of lasofoxifene for the postmenopausal treatment of osteoporosis, lasofoxifene significantly reduced the incidence of ER+ breast cancer. Further unpublished preclinical data have demonstrated significant in vitro and in vivo efficacy in non-clinical breast cancer models including models with and without ESR1 mutants. Moreover, lasofoxifene significantly reduced metastases in ESR1 mutated models. These non-clinical and clinical data provide a strong rationale to pursue a phase 2 clinical trial in women with ER+, ESR1 mutated MBC.

This open-label, multi-center study will compare the efficacy and tolerability of lasofoxifene (5 mg orally daily) to fulvestrant (IM 500 mg D1,15,29 and then q30 D) in a 1:1 randomization. Inclusion criteria include postmenopausal women with ER+ advanced breast cancer; progression on a non-steroidal AI in combination with a CDK 4/6 inhibitor; and a known ESR1 mutation. Approximately 90 patients with measurable or evaluable disease (i.e. bone only) will be recruited to have at least 40 patients per treatment arm. The primary endpoint will be progression free survival (PFS) with secondary endpoints of objective response rate (ORR), clinical benefit rate (CBR), duration of response (DoR) and time to response (TTR). It is assumed that lasofoxifene will double the median PFS compared to fulvestrant in this ESR1 mutation patient population for a hazard ratio 0.5 and a power of 89% to reach a 1-sided p of <0.05.

The study will commence in 4Q2018 and will complete recruitment in 1 year. It is anticipated that 25-30 centers in the US will be participating.

Citation Format: Plourde PV, Schwartzberg LS, Greene GL, Portman DJ, Komm BS, Jenkins SN, Liu P-Y, Portman MD, Goetz MP. An open-label, randomized, multi-center phase 2 study evaluating the activity of lasofoxifene relative to fulvestrant for the treatment of postmenopausal women with locally advanced or metastatic ER+/HER2 - breast cancer (MBC) with an ESR1 mutation [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT1-01-02.

Abstract P2-08-66: Outcomes among metastatic breast cancer patients with characteristics that confer a less favorable prognosis

Background: Recent advances in the treatment of hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) have contributed to increased overall survival (OS). Despite advances, MBC remains incurable and there is a subset of patients with clinical features that are associated with poorer prognosis. This study described the patient characteristics, treatment patterns, and outcomes of a cohort of US patients with HR+, HER2- MBC as a function of various factors associated with poor prognosis, including presence (vs. absence) of liver metastases (LM).

Methods: This retrospective study used US community oncology electronic health record data from the Vector Oncology Data Warehouse. Eligible women who received systemic treatment for MBC, had a diagnosis of MBC in 2008 or later, and had completed at least three Patient Care Monitor (PCM) surveys, (a patient-reported outcomes survey collected as a part of clinical care), were included. OS was measured from the start of the first three regimen-based lines (1L, 2L and 3L) of treatment; patients without evidence of death were censored at the last observed visit. The statistical significance of differences in categorical and continuous variables between LM positive (LM+) and LM negative (LM-) were evaluated with chi-square (X2) tests, and t-tests, respectively. Kaplan-Meier and Cox analyses were applied to evaluate differences in OS by LM status and by line of therapy at the start of MBC treatment (unadjusted for treatment).

Results: A total of 378 women, 98.4% residing in the South and 40.5% African-American, were included; 295 (78.0%) were LM- at the time of diagnosis. Following 1L, approximately 82.8% and 60.8% of patients received 2L and 3L, respectively. Patients with a LM+ status had a lower mean age (mean: 57.2, SD: 13.8 vs. 61.2, 13.1; p=0.016) and a higher percentage had a grade 3 tumor (36.1 vs. 24.7%; p=0.039) compared to patients with LM-status. Table 1 shows the OS results for 1L-3L. For all 3 lines, median OS for LM+ was shorter than the LM- median OS. LM+ patients had a poorer prognosis as they were more likely to have an OS event across 1L-3L compared to LM- patients.

Conclusions: Among this community oncology cohort, median OS in 1L was 14 months shorter in LM+ patients compared to LM- patients. It is important to note that the sample size and selection criteria may limit generalizability of these results. Despite progress in treating women with MBC, treatment options are lacking for patients with less favorable prognosis, including those with LM. Other potential indicators of poor prognosis, such as high tumor grade, are being explored.

Table 1.OS (months) by regimen-based line of therapy Measure Liver Mets (LM+) No Liver Mets (LM-) HR p-value 1L, # of Events/ # of Patients55/83168/295  Median (95% CI)23.9 (15.5-28.6)35.2 (30.1-42.3) <0.0001* Cox Hazard Ratio  1.93<0.0001 2L, # of Events/ # of Patients48/72149/241  Median (95% CI)16.6 (12.0-22.6)24.2 (21.3-29.0) 0.002* Cox Hazard Ratio  1.490.040 3L, # of Events/ # of Patients35/52118/178  Median (95% CI)11.5 (7.0-21.0)17.4 (14.7-20.0) 0.038* Cox Hazard Ratio  1.540.060CI=Confidence Interval; *p-value was derived using log rank test.

Citation Format: Saverno K, Cuyun Carter G, Dufour R, Price G, Li L, DeLuca A, Nash Smyth E, Battiato L, Gable J, Walker MS, Huang Y-J, Hannas S, Schwartzberg LS. Outcomes among metastatic breast cancer patients with characteristics that confer a less favorable prognosis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-66.

Abstract P2-09-09: Polyligand profiling differentiates cancer patients according to their benefit of treatment

Introduction: Deconvolution of multi-nodal perturbations in cancer network architecture demands highly multiplexed profiling assays. We demonstrate the value of polyligand profiling of tumor systems states using libraries of single stranded oligodeoxynucleotides (ssODN) to distinguish between tumor tissue from breast cancer patients who did or did not derive benefit from treatment regimens containing trastuzumab.

Methods: This study included cases from women with invasive breast cancer who received chemotherapy+ trastuzumab (C+T) or trastuzumab monotherapy with available retrospective data on the time to next treatment (TTNT). A library of 2x1012 unique ssODN was exposed to FFPE tissues from patients who benefited (B) or not (NB) from trastuzumab-based regimens in several rounds of positive and negative selection. Two enriched libraries were screened on independent set of 42 B and 19 NB cases using a modified IHC protocol for detection of bound ssODNs. Poly-Ligand Profiles (PLP) were scored by a blinded pathologist. Two libraries, EL-NB and EL-B, showed significant p-values between groups of responders and non-responders. A Cox-PH model was fitted using either tumors' HER2 status or PLP test results as the independent variable. Median survival time was calculated from the Kaplan-Meier estimate. A separate group of 63 cases with TTNT data from chemotherapy without trastuzumab was used as a control to distinguish prognostic from predictive performance.

Results: The PLP scores of EL-NB and EL-B were assessed by receiver operating characteristic (ROC) curves and resulted in a combined AUC value of 0.81. EL-NB and EL-B were able to effectively classify B and NB patients with either HER2-negative/equivocal (AUC = 0.73) or HER2-positive cancers (AUC = 0.84). In contrast, HER2 status alone yielded an AUC value of 0.47. The combined PLP scores for the independent set of 63 patients treated with C excluding trastuzumab resulted in an AUC value of 0.53, indicating that the assay was predictive and not simply prognostic. Kaplan-Meier curves analysis shows that PLP+ cases have 429 days median TTNT, while PLP- cases have 129 days (HR = 0.38, log-rank p = 0.001). Analysis based on HER2 status showed no significant difference in TTNT between patients that were HER2+ (280 days) or HER2-negative/equivocal (336 days, HR = 1.27, log-rank p =0.45).

Summary: Performance of the PLP assay in differentiating patients who did or did not benefit from trastuzumab therapy outperforms the standard IHC assay for HER2 status. These results represent a promising step towards the development of a CDx to identify the 50-70% of HER2+ patients who will not benefit from trastuzumab. In addition, PLP also has the potential to identify the HER2-negative/equivocal patients who may benefit from trastuzumab-containing regimens.

Citation Format: Domenyuk V, Gatalica Z, Santhanam R, Wei X, Stark A, Kennedy P, Toussaint B, Levenberg S, Wang R, Xiao N, Greil R, Rinnerthaler G, Gampenrieder S, Heimberger AB, Berry DJ, Barker A, Demetri GD, Quackenbush J, Marshall JL, Poste G, Vacirca JL, Vidal GA, Schwartzberg LS, Halbert DD, Voss A, Miglarese MR, Famulok M, Mayer G, Spetzler D. Polyligand profiling differentiates cancer patients according to their benefit of treatment [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 P2-09-09.

Abstract P5-11-09: Sustained efficacy of eflapegrastim in breast cancer patients in a phase 2, open-label, dose-ranging study

Background: Eflapegrastim is a distinct biologic that uses the innovative proprietary long-acting protein/peptide discovery technology (LAPSCOVERY™) and consists of a novel, modified recombinant human G-CSF conjugated to the Fc fragment of IgG4 via a polyethylene glycol linker. A Phase 2 study of 3 doses of eflapegrastim vs pegfilgrastim was conducted in breast cancer patients receiving docetaxel + cyclophosphamide (TC) chemotherapy.

Methods: This was an open-label, global, multicenter, dose-ranging study designed to compare the safety and efficacy of eflapegrastim relative to a fixed dose of pegfilgrastim as a concurrent active control. The study included 4 treatment arms: 3 dose levels of eflapegrastim (45 μg/kg, 135 μg/kg, and 270 μg/kg) vs pegfilgrastim (6 mg). The primary objective of the study was the Duration of Severe Neutropenia (DSN) during Cycle 1. The results for the primary objective, along with demographics and safety, were described in a previous presentation (SABCS 2015 P1-10-05). The secondary endpoints included DSN in Cycles 2-4, absolute neutrophil count (ANC) in Cycles 1-4, the overall incidences of febrile neutropenia (FN) and hospitalization rates.

Results: A total of 147 evaluable patients were enrolled. Patient and tumor characteristics were comparable across all 4 treatment arms. Median age was 59.0 years (range 32 to 77 years); most patients were <65 years (68%), Female (98%), and White (95%). The DSN for the 135 µg/kg and 270 µg/kg was non-inferior to pegfilgrastim during all cycles and the DSN for patients treated with 45 µg/kg was non-inferior during Cycles 2 and 3 (Table 1). The ANC was dose proportional across all 4 cycles. The incidence of FN and hospitalization rates was low in all arms and there were no significant differences between the Eflapegrastim and Pegfilgrastim Arms (Table 2).

Table 1. Duration of Severe Neutropenia in Cycles 2 to 4 of TC Chemotherapy by Treatment ArmDSN (Days)Eflapegrastim 45 μg/kg (N=39)Eflapegrastim 135 μg/kg (N=36)Eflapegrastim 270 μg/kg (N=36)Pegfilgrastim 6 mg (N=36)Cycle 2Difference with pegfilgrastim0.380.04-0.05NANon-Inferiority p-value0.001<0.001<0.001NACycle 3Difference with pegfilgrastim0.310.020.01NANon-Inferiority p-value0.002<0.001<0.001NACycle 4Difference with pegfilgrastim0.940.07-0.02NANon-Inferiority p-value0.781<0.001<0.001NADSN = Duration of Severe Neutropenia; NA = Not Applicable

Table 2. Incidence of Febrile Neutropenia and Hospitalizations Eflapegrastim 45 μg/kg (N=39)Eflapegrastim 135 μg/kg (N=36)Eflapegrastim 270 μg/kg (N=36)Pegfilgrastim 6 mg (N=36)Febrile NeutropeniaIncidence (%)3 (7.7%)1 (2.8%)1 (2.8%)2 (5.6%)Difference with Pegfilgrastim2.1 %-2.8%-2.8%NAp-value1.0001.0001.000NAHospitalizationsIncidence (%)3 (7.7%)3 (8.3%)1 (2.8%)5 (13.9%)Difference with Pegfilgrastim-6.2%-5.6%-11.1%NAp-value0.4690.7100.199NA

Conclusions: In breast cancer patients treated with TC, the non-inferiority of DSN of 135 µg/kg and 270 µg/kg eflapegrastim, compared to pegfilgrastim in Cycle 1, was sustained through Cycles 2-4 and the ANC profiles were comparable in Cycles 1-4. In addition, the overall incidence of FN and hospitalizations was comparable between the eflapegrastim arms and the pegfilgrastim arm.

Citation Format: Vacirca JL, Agajanian R, Papai Z, Horvath Z, Makharadze R, Ibrahim EN, Choi MR, Song T, Tedesco KL, McGregor K, Schwartzberg LS. Sustained efficacy of eflapegrastim in breast cancer patients in a phase 2, open-label, dose-ranging study [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 P5-11-09.

Abstract P5-11-07: Pharmacokinetics of eflapegrastim in a phase 2 open-label dose-ranging study in breast cancer patients receiving TC regimen

Background: Eflapegrastim (SPI-2012/HM10460A) is a novel, long acting recombinant human granulocyte colony-stimulating factor (rhG-CSF). Eflapegrastim consists of an rhG-CSF conjugated to the recombinant E coli derived Fc fragment of IgG4 via a polyethylene glycol linker. Eflapegrastim is in clinical development for the treatment of chemotherapy induced neutropenia in cancer patients.

Methods: Pharmacokinetics (PK) of eflapegrastim was investigated in an open label, dose-ranging Phase 2 study in breast cancer patients receiving docetaxel + cyclophosphamide (TC) chemotherapy. The study consisted of 4 arms. Patients in Arms 1 through 3 received subcutaneous doses of 45, 135, or 270 µg /kg of eflapegrastim and patients in Arm 4 received 6 mg pegfilgrastim (Neulasta®) on Day 2 of each 21-day chemotherapy cycle. Serum samples were collected from a subset of eflapegrastim patients at pre-specified time-points and analyzed for eflapegrastim by a validated enzyme-linked immunosorption assay (ELISA). Pharmacokinetic analyses were conducted on serum concentration-time profiles after dosing in Cycle 1. The serum concentrations for samples collected in Cycle 3 were compared with the corresponding concentrations in Cycle 1. Pharmacokinetic analyses were not conducted for pegfilgrastim patients.

Results: The PK profile of eflapegrastim was investigated in 11 patients, including 3 patients in the 45 µg/kg treatment arm, 4 patients in the 135 µg/kg treatment arm, and 4 patients in the 270 µg/kg treatment arm. Following single eflapegrastim doses of 45, 135, or 270 µg/kg, peak serum concentrations increased in a dose proportional manner. The summary of pharmacokinetics of eflapegrastim is presented in the Table below.

Pharmacokinetic Parameters of Eflapegrastim in Patients Following Single Subcutaneous Doses in Cycle 1ParameterEflapegrastim 45 μg/kg/Eflapegrastim 135μg/kgEflapegrastim 270 μg/kgCmax, ng/mLN = 3; Mean = 7.00; SD = 6.08N = 4; Mean = 247; SD = 276N =3; Mean = 299; SD = 329Tmax, haN =2; Mean = 58.7; SD = 46.9 - 70.5N = 4; Mean =9.00; SD = 8 - 48.1N = 3; Mean = 24.00; SD = 24 - 24.1AUC0-312, ng•hr/mLN = 0; Mean = NC; SD = NCN = 2; Mean = 16000; SD = 5850N = 3; Mean = 22900; SD = 25100t1/2, hbN = 0; Mean = NC; SD = NCN = 2; Mean = 81.0; SD = 88.4N = 1; Mean = 31.5; SD = NCAUC = area under the concentration-time curve; Cmax = maximum serum concentration; h = hour; NC = not calculated; SD = standard deviation; t1/2 = half-life; Tmax = time to maximum serum concentration; a) Expressed as median and range; b) Expressed as harmonic mean and pseudo SD

The maximum serum concentrations of eflapegrastim in Cycle 3 increased with the dose of eflapegrastim. The serum concentrations of eflapegrastim in Cycle 3 were generally lower than those in Cycle 1, but the profile was similar to Cycle 1.

Conclusions: The Cmax and AUC(0-312) of eflapegrastim increased in a dose proportional manner following subcutaneous administration. The half-life of eflapegrastim ranged from 31.5 to 81.0 hours, which is consistent with the half-life of other long-acting myeloid growth factors.

Citation Format: Vacirca JL, Papai Z, Horvath Z, Makharadze R, Reddy G, Song T, Koli P, Schwartzberg LS. Pharmacokinetics of eflapegrastim in a phase 2 open-label dose-ranging study in breast cancer patients receiving TC regimen [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 P5-11-07.

Abstract P4-12-08: Use of an aptamer library based next generation omics platform for the development of a novel trastuzumab predictive assay

Introduction: Previous attempts to use individual aptamers as diagnostic reagents have failed to consistently achieve performance comparable to antibodies. Here we report a novel systems biology approach using poly-ligand aptamer libraries to identify responders and non-responders to traztuzumab-based regimens in metastatic breast cancer.

Methods: To overcome the fundamental limitation of the individual aptamer binding affinities, large libraries (106 species) were created so that potentially thousands of aptamers could bind to each of a multitude of targets related to the whole cellular changes in response to trastuzumab therapy. A set of breast cancer patients, which received trastuzumab mono- or combined therapy for at least 7 months were classified as “Responders” (R); cases with particular regimen discontinued in the period not exceeding 5 months were classified as “Non-Responders”(NR). A library of 2x1012 unique 90-mer ssDNA oligodeoxynucleotides (ssODN) was trained on FFPE tissue of both R and NR patients. Partitioning of aptamer libraries was done by microdissection of the tumor tissue, after incubation of aptamer library with the entire tissue section, to drive selection pressure toward cancer cells. A total of 10 cases of R and NR, 6 Her2+ cases each, were used to train separate aptamer libraries, with 1 positive and 2 counter selection cases per enrichment. Enriched libraries were screened on 20 R and 20 NR cases (11 Her2+ cases each) by adopting modified immunohistochemistry protocol. Each library was used as an independent reagent (similar to an antibody in IHC) across all 40 cases to evaluate the efficacy of the aptamer library to distinguish differences between the R and NR groups. Staining (DAB chromogen) profiles were scored from 0 to 3+ (nuclear and cytoplasmic staining) by a pathologist without any knowledge of the clinical outcomes. Initial validation was done by t-test using raw histological scores. Four libraries showed significant p-values between groups of responders and non-responders, a classification algorithm was constructed and evaluated using area under the receiver-operator characteristic curve (AUC). The datasets of two best-performing libraries were combined into one model using logistic regression to further improved the classifier performance.

Results: Of seventeen trained libraries, eight were evaluated and four showed significant correlation to clinical benefit with a minimum accuracy of 75% for each library when evaluated independently. Furthermore, two libraries showed exceptional performance (ROC curve AUC of 0.86 and 0.77). Combination of the profiling data from these two libraries using logistic regression resulted in an AUC of 0.985. A prospective validation of aptamer histochemical theranostic testing has been initiated.

Summary: Enriched aptamer libraries appear to distinguish trastuzumab responsiveness in metastatic breast cancer. This technology could be used as an additional technique beyond FISH testing to determine sensitivity to anti-HER2 agents. The demonstrated platform is applicable to virtually any disease where the safe and effective use of corresponding drug is yet to be improved.

Citation Format: Spetzler D, Domenyuk V, Santhanam R, Wei X, Stark A, Wang J, Gatalica Z, Miglarese M, Vidal G, Schwartzberg LS. Use of an aptamer library based next generation omics platform for the development of a novel trastuzumab predictive assay [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 P4-12-08.

Abstract OT1-01-11: Randomized phase 3 study of a novel, long-acting G-CSF (eflapegrastim) versus pegfilgrastim in the management of chemotherapy-induced neutropenia in early-stage breast cancer patients receiving docetaxel and cyclophosphamide (TC) (ADVANCE study)

Background: Eflapegrastim is a distinct biologic that uses an innovative, proprietary long-acting protein/peptide discovery technology (LAPSCOVERY™). Eflapegrastim consists of a novel, modified recombinant human G-CSF conjugated to the Fc fragment of IgG4 via a polyethylene glycol linker to produce a new, longer-acting G-CSF with a potentially unique distribution to areas rich in Fc receptors including its site of action in the bone marrow. A successful dose-finding Phase 2 trial including a pegfilgrastim control arm established the dose for a Phase 3 non-inferiority trial.

Trial Design: This is a randomized, open-label, active-controlled, multinational, multicenter, Phase 3 study comparing the efficacy and safety of eflapegrastim to pegfilgrastim. Patients (n=580) will be randomized in a 1:1 ratio to receive either eflapegrastim (equivalent to 3.6 mg G-CSF) or pegfilgrastim (equivalent to 6.0 mg G-CSF) once per chemotherapy cycle (up to 4 cycles), approximately 24 hours after chemotherapy. The primary endpoint is to compare the efficacy of a single dose of eflapegrastim with pegfilgrastim in patients with ESBC receiving TC, as measured by the Duration of Severe Neutropenia (DSN) in Cycle 1. Key secondary objectives include Time to Absolute Neutrophil Count (ANC) Recovery in Cycle 1; Depth of ANC Nadir in Cycle 1; incidence of Febrile Neutropenia. Safety and pharmacokinetics will also be assessed.

Eligibility Criteria: This study is enrolling histologically confirmed ESBC patients who are: eligible to receive adjuvant or neoadjuvant TC chemotherapy; at least 18 years of age, with adequate hematologic, renal and hepatic function. Patients will be excluded if they have: active concurrent malignancy or life-threatening disease; a known sensitivity or previous reaction to E. coli derived products or any of the products to be administered during study participation; concurrent adjuvant cancer therapy; locally recurrent/metastatic or contralateral breast cancer; previous exposure to filgrastim, pegfilgrastim, or other G-CSF products in clinical development prior to the administration of study drug; bone marrow or hematopoietic stem cell transplant or radiation therapy prior to enrollment, or are pregnant or breast-feeding.

Statistical Methods: The goal of this study is to demonstrate non-inferiority. For the Primary Efficacy Analysis, the mean DSN in Cycle 1 will be compared between the eflapegrastim and pegfilgrastim treatment arms. A 2-sided 95% confidence interval (CI) of the difference between the mean DSN of the eflapegrastim arm and the mean DSN of the pegfilgrastim arm will be calculated using bootstrap resampling with treatment as the only stratification factor. For the Secondary Efficacy Analyses, the results will each be summarized by treatment arm and cycle. The two-sided 95% CI for the difference between the treatment arms will be calculated.

Target Accrual: Approximately 580 patients. Enrollment began January 2016.

Contact Information: Spectrum Pharmaceuticals. advance@sppirx.com.

Citation Format: Schwartzberg LS, Bharadwaj J, Peguero JA, Vacirca JL, Ibrahim EN, Bhat G, Choi MR, McGregor K, Agajanian R. Randomized phase 3 study of a novel, long-acting G-CSF (eflapegrastim) versus pegfilgrastim in the management of chemotherapy-induced neutropenia in early-stage breast cancer patients receiving docetaxel and cyclophosphamide (TC) (ADVANCE study) [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 OT1-01-11.

Abstract P5-11-08: Immunogenicity of eflapegrastim in a phase 2 open-label dose-ranging study of eflapegrastim in breast cancer patients receiving TC regimen

Background: Eflapegrastim (SPI-2012/HM10460A) is a novel, long-acting recombinant human granulocyte colony-stimulating factor (rhG-CSF). Eflapegrastim consists of an rhG-CSF conjugated to a recombinant E. coli derived Fc fragment of IgG4 via a polyethylene glycol linker. Eflapegrastim is in clinical development for the treatment of chemotherapy induced neutropenia in cancer patients.

Methods: Immunogenicity of eflapegrastim was investigated in an open label, dose-ranging Phase 2 study in breast cancer patients receiving docetaxel + cyclophosphamide (TC) chemotherapy. The study consisted of 4 arms. Patients in Arms 1 through 3 received subcutaneous doses of 45, 135, or 270 µg/kg eflapegrastim and Arm 4 received 6 mg pegfilgrastim (Neulasta®) on Day 2 of each 21-day chemotherapy cycle. Blood samples for immunogenicity analysis were collected before the start of each chemotherapy cycle (Day 1) and at the End-of-Study Visit. Samples were tested in a screening assay for Anti-Drug Antibodies (ADA) to eflapegrastim by a validated enzyme linked immunosorption assay (ELISA). Positive samples from the screening assay were further tested in a confirmatory assay for antibodies binding to eflapegrastim or G-CSF. Samples found positive in the confirmatory assay were further tested in a validated cell based neutralizing antibody assay.

Results: Serum samples from 143 patients in the study were tested for ADA to eflapegrastim and G-CSF. Preexisting antibodies binding to eflapegrastim or G-CSF were detected in 9 out of 143 (6.3%) patients. One out of the 27 patients (3.7%) in the Pegfilgrastim Arm who was negative prior to dosing was positive for ADA in the G-CSF confirmatory assay. Two out of 100 patients (2.0%) treated with eflapegrastim, who were negative prior to dosing, demonstrated treatment-induced formation of ADA in the G-CSF confirmatory assay. However, the responses in these patients were transient (ie, not consistently positive at all the sampling times) and the assay response values were low and only slightly above the plate-specific cut points. None of the patients tested were positive for G-CSF neutralizing antibodies. A formal assessment of the impact of serum ADA on the PK of eflapegrastim was not performed since PK was examined in only a limited number of patients and all of those patients were negative for ADA both at study initiation and post-dose.

Conclusion: No neutralizing antibodies against eflapegrastim or G-CSF were detected in patients administered eflapegrastim in this study.

Citation Format: Vacirca JL, Papai Z, Agajanian R, Horvath Z, Makharadze R, Ibrahim E, Koli P, Reddy G, Tedesco KL, McGregor K, Schwartzberg LS. Immunogenicity of eflapegrastim in a phase 2 open-label dose-ranging study of eflapegrastim in breast cancer patients receiving TC regimen [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 P5-11-08.

Abstract P6-12-06: Nonsteroidal, tissue selective androgen receptor modulator (SARM), enobosarm, reduces growth of androgen receptor-positive breast cancer in patient-derived preclinical models

Introduction: In breast cancer the androgen receptor (AR) is the most abundantly expressed steroid receptor with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing the AR. Historically, advanced breast cancer has been treated with androgens, resulting in significant clinical response. However, the use of steroidal androgens fell from favor as a result of their virilizing side effects. Nonsteroidal, tissue selective androgen receptor modulators (SARMs) will provide a novel targeted approach to exploit the therapeutic benefits of androgens in breast cancer.

Aims: To test the effects of enobosarm (a first-in-class SARM) and enzalutamide (AR antagonist) on the growth of patient-derived breast cancer xenografts (PDX) and to discern the mechanism of action of AR-targeted therapies in AR-positive breast cancer.

Materials and Methods: AR-positive PDXs with varying receptor expression (ER, progesterone receptor (PR), and HER2) were implanted in immunecompromised mice. Mice carrying PDXs were treated with vehicle, 10 mg/kg/day (mpk) enobosarm (GTx, Inc., Memphis, TN), or 20 mpk enzalutamide (Medivation Inc.), orally. Tumor volume was measured twice or thrice weekly. Tumors that received enobosarm were further analyzed to determine the mechanism of action.

Results: Enobosarm significantly (p<0.01) inhibited the growth of ER-, PR-, and HER2- positive HCI-7 and ER- and PR- negative and HER2-positive HCI-12 PDX. While enobosarm inhibited the growth of HCI-12 by ~80% and HCI-7 by ~60%, enzalutamide failed to inhibit the growth of the HCI-7 PDX. In contrast, neither enobosarm nor enzalutamide inhibited the growth of ER- and PR-negative and HER2-positive HCI-9 PDX, consistent with the heterogeneity of AR-positive breast cancers. Growth of two triple-negative breast cancer (TNBC) PDXs were inhibited by 30-40% by enobosarm, but not by enzalutamide. These results were reproduced in xenografts developed with breast cancer cell lines, MCF-7 and MDA-MB-231 expressing the AR. Gene expression studies conducted with the HCI-12 tumors indicated that enobosarm inhibited the expression of various proliferative genes (MUC2, IL10RA, IGSF1, SLC6A4, and others) and increased the expression of growth inhibitory genes (CYP4F8, MYBPC1, and others). Ingenuity pathway analysis demonstrated that enobosarm inhibited genes that are downstream of HER2 signaling. Interestingly, miR-21-3p, which has been implicated in chemo-resistance, was consistently expressed at approximately 10-50-fold higher than miR-21-5p in PDXs. This imbalance was partially reversed by enobosarm.

Conclusion: These results indicate that AR-positive breast cancers are highly heterogeneous and that enobosarm has promise as novel targeted therapy to treat AR-positive breast cancer. Enobosarm is currently in phase II clinical trial in both ER-positive breast cancer and in TNBC patients.

Citation Format: Narayanan R, Ponnusamy S, Fan M, Yang CH, Grimes BL, Fleming MD, Pritchard EF, Berry MP, Oswaks RM, Fine RE, Loiseau J-C, Schwartzberg LS, Pfeffer LM. Nonsteroidal, tissue selective androgen receptor modulator (SARM), enobosarm, reduces growth of androgen receptor-positive breast cancer in patient-derived preclinical models [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 P6-12-06.

Abstract P5-20-08: Phase II trial of ixabepilone (Ixa) and dasatinib (D) for treatment of metastatic breast cancer (MBC)

Background: Ixa is a novel semi-synthetic epothilone microtubule blocking agent with activity in taxane and anthracycline-resistant MBC. D is a potent small molecule tyrosine kinase inhibitor with substantial activity against SRC family non-receptor kinases, known to play multiple roles in promoting tumor growth and metastases. D inhibits cellular SRC autophosphorylation in cell lines that highly express SRC and inhibits in vivo activation in a broad array of tumors in nude mice. Ixa and D have synergistic effects in preclinical models suggesting this strategy would be of clinical benefit as combination therapy. A phase I trial of the combination determined the maximally tolerated doses of ixabepilone at 20 mg/m2 weekly and dasatinib 100 mg po daily with objective responses seen. Neutropenia was the dose limiting toxicity.

Methods: Multicenter single arm phase II trial. Eligibility: Measurable or evaluable disease by RECIST 1.0, ECOG PS 0–2, HER2− or HER2 refractory, no CYP 3A4 inducers or inhibitors, no H2 blockers or PPIs, no pleural/pericardial effusion, exposure to 1 or 2 prior lines of chemotherapy in the metastatic setting, peripheral neuropathy ≤ grade 1. The primary endpoint was progression-free survival (PFS). Assessment for response was performed every 8 weeks. The treatment schedule was D at 100 mg po daily starting day 1, and Ixa 20 mg/m2 Day 1, 8, 15 every 28 days (1 cycle).

Results: The study met its accrual goal with 50 patients (pts) enrolled on the phase II dosing, including six from the phase I portion. As of May 21, 2012, 47 pts are evaluable. The median age was 55 (range, 34–70), 19 African-American, 46 ECOG PS 0–1, median number of metastatic sites, three. Forty pts had prior taxanes, 24 prior anthracyclines. Median PFS was 6.0 months (95% CI, 2.9–8.0), achieving pre-specified value of interest for further study of the combination. The overall unconfirmed response rate was 14.9% with a clinical benefit rate (CR+PR + stable at 24 weeks) of 25.5%. Six pts continued D monotherapy after eight cycles of Ixa + D. All-grade adverse events (AEs) occurring in >15% of pts included anemia (45%), neutropenia (32%), nausea (51%), vomiting (32%) diarrhea (51%), fatigue (53%), anorexia (25%) dysgeusia (32%), headache (28%), peripheral neuropathy (34%) cough (28%) alopecia (21%) and hypokalemia (19%). Grade 3/4 adverse events occurred in 30 patients, with only four experiencing grade 4 AEs, three neutropenia and one chest pain. No grade 3/4 febrile neutropenia occurred. Grade 3 AEs of interest included two pts with peripheral neuropathy and 1 with pleural effusion.

Conclusions: The combination of Ixabepilone weekly + Dasatinib orally daily is an active and well tolerated regimen in pretreated MBC with manageable toxicity. Updated results will be reported.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-08.

Abstract P2-05-06: Quantitative measurement of HER2 expression in breast cancers: comparison with “real world” HER2 testing in a multi-center Collaborative Biomarker Study (CBS) and correlation with clinicopathological features

Background: Accurate determination of HER2 status is critical in determining appropriate therapy for breast cancer patients. The HERmark® assay is a novel method to quantitatively measure HER2 total protein expression (H2T) in breast cancer. In this study, we compared HERmark H2T with central laboratory HER2 retesting and local (site reported) HER2 testing of formalin-fixed, paraffin-embedded (FFPE) breast cancer tissues. The quantitative total HER2 measurements (H2T) by HERmark and results of local HER2 tests were correlated with tumor pathohistological characteristics and overall survival of breast cancer patients.

Methods: 232 FFPE breast cancer tissues were provided by 11 CBS study sites for HER2 testing by the HERmark assay and central laboratory IHC re-testing performed in blinded fashion. Local HER2 immunohistochemistry and/or fluorescence in situ hybridization (FISH) results and valid HERmark H2T and central HER2 IHC results were obtained in 192 cases for analysis.

Results: H2T showed a significant correlation with central HER2 IHC staining intensity (P < 0.0001). The concordance rates of positive and negative HERmark status (excluding equivocal) with those of local HER2 status determined by the CBS sites, and with those of central HER2 IHC status were 84% (Kappa = 0.68) and 96% (Kappa = 0.91), respectively. Higher H2T levels significantly correlated with higher tumor grade (p = 0.007) and negative ER/PR status (p = 0.002). Twenty-six (14%) cases showed discordant (conversion of negative and positive) results between local HER2 status and HERmark status. Of the discordant cases, HERmark significantly agreed with H-score of central HER2 IHC retesting (p = 0.014), as compared with local HER2 status. The concordant negative group (local HER2 negative/H2T low) demonstrated better overall survival (OS) (HR = 0.198, p = 0.0001), compared to that of concordant positive group (local HER2 positive/H2T high). The concordant negative group also showed better OS than that of discordant local HER2 negative/H2T high group (HR = 0.065, p = 0.0003), but showed no significant difference in OS as compared to that of discordant local HER2 positive/H2T low group (HR = 1.774, p = 0.499).). In 24 cases (13%) considered to be “triple negative” by local HER2, ER and PR testing, HERmark re-classified 4 cases (17%) as HER2 positive.

Conclusions: H2T by HERmark yields a continuum of quantitative HER2 protein measurements that shows an excellent correlation with central HER2 IHC retesting and confirms the known correlations between HER2 expression with tumor grade and ER/PR status. OS results of concordant HER2 positive or negative groups (between local HER2 testing and HERmark H2T) confirmed that HER2 positive patients (excluding adjuvant trastuzumab therapy) have worse OS than patients with HER2 negative disease. However, in the HERmark and local HER2 discordant groups, OS appeared to track better with H2T by HERmark and not with the local HER2 status. Novel quantitative HER2 measurements may identify patients with false (+) and (−) HER2 status by local HER2 testing and may provide added clinical value to routine “real world” HER2 testing.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-05-06.

OT3-01-09: Phase 3 Trial Comparing Capecitabine in Combination with SorafenIb or Placebo for Treatment of Locally Advanced or Metastatic HER2−Negative Breast Cancer (RESILIENCE)

Sorafenib (SOR) is an oral multikinase inhibitor with antiangiogenic and antiproliferative activity. SOR is currently indicated for renal cell and hepatocellular carcinoma, with indications in other tumor types being explored. In a double-blind, randomized phase 2b screening trial (SOLTI-0701) in patients with advanced HER2−negative breast cancer (BC), the addition of SOR to capecitabine (CAP) showed a statistically significant improvement in the primary endpoint of progression-free survival (PFS) compared with placebo (PL)+CAP (median 6.4 vs 4.1 mo; hazard ratio=0.58; 1-sided P=0.0006). The combination was tolerable. Grade 3/4 adverse events were comparable between treatment arms with the exception of grade 3 hand-foot skin reaction/syndrome (HFSR/HFS) (44% in SOR+CAP vs 14% in PL+CAP). The SOLTI-0701 results indicate a potential role for the oral combination of SOR+CAP in the treatment of BC and support a phase 3 trial.

Design: RESILIENCE is an ongoing multinational, double-blind, PL-controlled, randomized phase 3 trial designed to assess SOR+CAP as a first- or second-line therapy in advanced HER2−negative BC. Eligibility criteria include: ≥18 years of age; ≤1 prior chemotherapy regimen for advanced BC; and resistant to/failed taxane and anthracycline or no indication for further anthracycline treatment. Prior hormonal or radiation therapy is allowed, but prior use of VEGF inhibitors is not. Patients with significant cardiovascular disease or active brain metastases are not eligible. Patients are stratified by hormone receptor status, geographic region, and prior chemotherapy for advanced BC and randomized (1:1) to CAP (1000 mg/m2 po twice daily [BID], days 1–14 of a 21-day cycle) in combination with SOR (po BID, days 1–21, total dose 600 mg/day) or matching PL. CAP and SOR/PL doses can be escalated to 2500 mg/m2 per day and 800 mg/day, respectively, as tolerated. The protocol outlines strategies to manage toxicities with dose interruption and reduction. Dose re-escalation after reduction is allowed for SOR/PL (per protocol guidance) but not for capecitabine. Guidelines are provided for prophylactic and symptomatic treatment of HFSR/HFS. Radiographic assessment is every 6 wk for the first 36 wk, and every 9 wk thereafter. The primary endpoint is PFS. Assuming a 1-sided alpha of 0.005 and a power of 98.9%, the sample size is estimated at ∼519 patients, with primary analysis planned after 363 events. Secondary endpoints include overall survival, time to progression, overall response rate (RECIST 1.1 criteria), duration of response, and safety. In addition, patient reported outcomes will be assessed, and the trial will include an exploratory analysis of biomarkers. Enrollment began in Nov 2010. The trial is registered at ClinicalTrials.gov (NCT01234337).

Conclusions: RESILIENCE will provide definitive PFS data for SOR+CAP as a first- or second-line therapy in HER2−negative locally advanced or metastatic BC. The phase 3 design and improved dosing guidance since SOLTI-0701 will better characterize the benefit-to-risk profile of this regimen.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT3-01-09.

Phase III trial of gemcitabine plus docetaxel versus capecitabine plus docetaxel with planned crossover to the alternate single agent in metastatic breast cancer

BACKGROUND

Safety and efficacy of gemcitabine plus docetaxel (GD) and capecitabine plus docetaxel (CD) were compared in patients with metastatic breast cancer, where the alternate crossover monotherapy (GD→C or CD→G) was predetermined.

PATIENTS AND METHODS

Patients were randomly assigned to 3-week cycles of either gemcitabine 1000 mg/m(2) on days 1 and 8 plus docetaxel 75 mg/m(2) on day 1 or capecitabine 1000 mg/m(2) twice daily on days 1-14 plus docetaxel 75 mg/m(2) day 1. Upon progression, patients received crossover monotherapy. Primary end point was time to progression (TtP). Secondary end points evaluated overall response rate (ORR), overall survival (OS), and adverse events (AEs).

RESULTS

Despite over-accrual of 475 patients, the trial matured with only 324 of 385 planned TtP events due to patient discontinuations. Human epidermal growth factor receptor 2 status was not captured in this study. More CD patients (28%) discontinued due to AEs than GD patients (18.0%, P = 0.009). TtP [hazard ratio (HR) = 1.101, 95% confidence interval (CI) 0.885-1.370, P = 0.387] and OS (HR = 1.031, 95% CI 0.830-1.280, P = 0.785) were not significantly different comparing GD and CD. ORR was not statistically different (P = 0.239) comparing GD (72 of 207, 34.8%) and CD (78 of 191, 40.8%). TtP, OS, and ORR were not significantly different comparing crossover groups. GD caused greater fatigue, hepatotoxicity, neutropenia, and thrombocytopenia but not febrile neutropenia; CD caused more hand-foot syndrome, gastrointestinal toxicity, and mucositis.

CONCLUSIONS

GD and CD produced similar efficacy and toxicity profiles consistent with prior clinical experience.

Phase IIb double-blind, randomized, placebo-controlled trials for the efficacy and safety of sorafenib in patients (pts) with metastatic or locally advanced breast cancer (BC): Review of the Trials to Investigate the Effects of Sorafenib in BC (TIES) program

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Sorafenib is a potent multikinase inhibitor approved by the FDA and EMEA for the treatment of advanced renal cell carcinoma and hepatocellular carcinoma. As a single agent, sorafenib has been shown to have activity in pts with BC. Here, we review the TIES program, a compilation of currently ongoing investigator-sponsored phase IIb multinational, randomized, double-blind, placebo-controlled studies that aim to determine the optimal sequencing of pharmacologic agents for the treatment of BC. All studies will combine sorafenib with first- and/or second-line chemotherapy and/or hormonal therapy in pts with HER2-negative metastatic or locally advanced BC, enroll 220 pts, stratify pts by visceral vs nonvisceral disease, allow pts with evaluable and measurable disease, and include pts with treated brain metastases. The primary endpoint of all trials will be progression-free survival. Secondary endpoints will be safety, overall survival, objective response rate, duration of response, and time to progression. Some studies will also assess quality of life, pharmacokinetic sampling, and biomarkers. Additional information on four of the trials is shown below (Table). Patient characteristics and accruals will be reported.

[Table: see text]

No significant financial relationships to disclose.

An observational study of the impact of ethnicity on patients treated for non-small cell lung cancer (NSCLC) in the second-line setting with pemetrexed: Preliminary results in African Americans

e20624

Background: African-Americans are more likely to develop and die from lung cancer than persons of any other ethnic group. Historically, African-Americans have been under-represented in oncology clinical research. This prospective, single-arm, observational study evaluates the impact of ethnicity on disease control rate (DCR) (CR + PR + SD)) in patients (pts) with non-small lung cancer (NSCLC) being treated with pemetrexed (Pem) in the second-line setting. Methods: Eligibility criteria include stage IIIB or IV NSCLC pts receiving Pem for second-line therapy with no restrictions on performance status. An accrual of 200 African-Americans, 200 Hispanics, 200 Asian-Americans, and 400 Caucasians is planned to test the hypothesis that subjects from these minority populations with advanced NSCLC will have DCRs that are not inferior to Caucasian subjects during second-line treatment with Pem in routine clinical practice. This report describes observations from an early examination of the data of the Caucasian and African-American pts enrolled. Results: 293 pts have been enrolled in this study including 243 Caucasians and 34 African-Americans. Demographics of Caucasians: M/F (136:107); median age 66 (range 37–88); histology adenocarcinoma/squamous/other/unknown (141:67:33:2). Demographics of African-Americans: M/F (21:13); median age 64 (range 43–80); histology adenocarcinoma/squamous/other/unknown (22:9:3:0). DCR in Caucasians: 38% (CI= 28–47%: 3 CR, 8 PR, and 34 SD in 120 of the 243 pts). DCR in African-Americans: 61% (CI=36–86%: 0 CR, 0 PR, and 11 SD in 18 of the 34 pts). Updated safety and efficacy data will be available. Conclusions: Preliminary results based on limited data do not indicate an inferior response for African-American pts compared to Caucasian pts being treated with Pem for NSCLC in the second-line setting. Additional data are needed to establish a definitive conclusion.

[Table: see text]

The importance of histology when evaluating the cost-effectiveness of pemetrexed plus cisplatin as first-line therapy for advanced non-small cell lung cancer

e17533

Background: A recent randomized phase III study was the first to report survival differences between first-line platinum doublets based on non-small cell lung cancer (NSCLC) histology (Scagliotti et al, J Clin Oncol. 2008). Here, we estimate the cost-effectiveness of cisplatin/pemetrexed (Cis/Pem) compared to other common regimens in an overall NSCLC population and in histology subgroups. Methods: A semi-Markov model was developed to compare the two-year impact of Cis/Pem to cisplatin/gemcitabine (Cis/Gem), carboplatin/paclitaxel (Carb/Pac) and carboplatin/paclitaxel/bevacizumab (Carb/Pac/Bev) from the US payer perspective. Data from the randomized controlled clinical trial and a mixed treatment comparison model (Vansteenkiste et al, Proc. ITOC 2008) provided clinical inputs. Medicare reimbursement rates were used to determine drug costs. A retrospective claims database analysis was used to obtain estimates of other direct NSCLC-related costs, including drug administration and toxicity management. Nonsquamous histology subgroups explored were adenocarcinoma, large cell and not otherwise specified (NOS). Comparisons with Carb/Pac/Bev were limited to the nonsquamous histology subgroup. Results: In all patients regardless of histology, using Cis/Pem led to an incremental cost per life-year gained (LYG) of $104,577 vs. Cis/Gem and $231,291 vs. Carb/Pac. In the subset of patients with nonsquamous NSCLC (adenocarcinoma, large cell, or NOS), the incremental cost per LYG was $83,537 vs. Cis/Gem and $178,613 vs. Carb/Pac. Further specifying the population to include only those with adenocarcinoma or large cell NSCLC yielded an incremental cost per LYG of $72,325 vs. Cis/Gem and $132,547 vs. Carb/Pac. The incremental cost per LYG for Carb/Pac/Bev vs. Cis/Pem was more than $300,000. Conclusions: In an unselected advanced NSCLC population, Cis/Pem may not be considered cost-effective for first-line therapy; however, in its licensed indication of nonsquamous NSCLC, it can be considered cost-effective and even more so for patients with adenocarcinoma or large cell carcinoma. This analysis emphasizes the importance of histology in identifying the appropriate patient for Cis/Pem first-line chemotherapy.

[Table: see text]

Phase III trial of gemcitabine plus docetaxel (GD) compared to capecitabine plus docetaxel (CD) with planned crossover to the alternate single agent in metastatic breast cancer (MBC)

1000

Background: GD and CD are efficacious in patients (pts) with MBC. This study compared safety and efficacy of GD and CD induction regimens, where the alternate, single-agent, crossover therapy (GD to C or CD to G) was predetermined. Primary endpoint was time to progressive disease (TTP). Secondary endpoints included toxicities, overall response (ORR), and overall survival (OS). Methods: This multicenter, open-label, phase III study enrolled MBC pts with possible prior anthracycline therapy, adjuvant or neoadjuvant taxane therapy, but no taxane therapy for MBC ≤6 months prior to entry. Enrollment of 442 pts (221 per arm) was planned with 385 progressions required to achieve 80% power for a 2-month observed difference in median TTP between arms. Pts were randomized to: GD: G 1,000mg/m2 Days 1, 8 plus D 75 mg/m2 Day 1, q21 days; or CD: C 1,000 mg/m2 BID, Days 1–14 plus D 75 mg/m2 Day 1, q 21 days. Upon disease progression, pts were given crossover C or G at doses and schedules identical to induction. ORR was assessed by RECIST. Results: Demographics of 472 enrolled pts were balanced between arms; 57% had prior anthracycline. GD caused greater myelosuppression than CD, but without greater febrile neutropenia. Gastrointestinal toxicities, mucositis, and hand-foot syndrome were greater with CD. More pts in the CD arm (n=61, 26.2%) versus the GD arm (n=41, 17.2%) discontinued due to toxicity (p=0.023). ORR, TTP, and OS were not significantly different comparing GD and CD. However, ORR and TTP were significantly greater for the GD to C crossover monotherapy compared to CD to G. Post-hoc analysis of crossover pts showed that the TTP sum from induction through crossover was 6.1 months greater for GD to C. Conclusions: GD and CD had similar efficacy with toxicity profiles consistent with prior clinical experience. Results suggest that the GD to C crossover sequence may provide a clinical benefit over CD to G.

[Table: see text]

[Table: see text]

An open-label, dose-escalating study of Maxy-G34, a novel potent, long-acting Pegylated G-CSF, compared with pegfilgrastim (PF) for the treatment of chemotherapy induced neutropenia (CIN)

e14500

Background: rhG-CSF reduces the incidence and duration of CIN in patients (pts) receiving myelosuppressive chemotherapy. Maxy-G34 is a recombinant, modified human G-CSF, containing three 5 kD PEG groups. These modifications alter both renal and receptor mediated clearance, leading to a longer half-life and the potential for enhanced activity. Phase I studies demonstrated safety of Maxy-G34 in normal volunteers with a dose dependent rapidly reversible increase in the absolute neutrophil count (ANC). The effect of Maxy-G34 on CIN was evaluated in an open-label, active-comparator controlled, dose-ranging study. Methods: The primary efficacy endpoint was duration of severe, Grade 4 neutropenia (G4N) in treatment cycle 1. Adults with high-risk Stage I-IIIa breast cancer eligible for TAC chemotherapy received Maxy-G34 at 10, 30, 45, 60 or 100 μg/kg or the active control PF 6 mg, given sub- cutaneously 24-hours after each dose of TAC for 6 cycles. Blood samples were collected daily and analyzed at a central laboratory throughout each of the 21-day chemotherapy cycles to determine ANC and evaluate PK profile of Maxy-G34. Results: All dose groups of Maxy-G34 enrolled 6 pts each, except the 100 μg/kg group (3 pts), and the PF group (8 pts). The mean durations of G4N in cycle 1 were 2.2 days for 10 μg/kg, 1.8 days for 30 μg/kg, 0.8 days for 45 μg/kg, 2.2 days for 60 μg/kg, and 1.7 days for 100 μg/kg Maxy-G34 groups vs. 2.0 days for PF. The rate of FN was 2.6% across all Maxy-G34 doses vs. 4.2% for PF. CD34+ cell counts increased across Maxy-G34 groups following recovery from nadir with maximum concentration in treatment cycle 1 ranging from 25.8 to 133.3 cells/mL versus 49.6 cells/mL for PF. The average half-life and Cmax obtained after Maxy-G34 were approximately 2-fold higher than PF. Adverse events were consistent with those reported for G-CSF and TAC with no serious unexpected adverse events. Grade 3/4 AEs for Maxy-G34 was 9.5% vs. 8.5% for PF. No neutralizing antibodies related to Maxy-G34 were observed. Conclusion: Once-per-cycle Maxy-G34 appears to be effective in reducing CIN with no new safety signals. Further Phase II studies are planned.

[Table: see text]

Single-agent lapatinib for HER2-overexpressing advanced or metastatic breast cancer that progressed on first- or second-line trastuzumab-containing regimens

BACKGROUND

This phase II study evaluated the efficacy and safety of lapatinib in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer that progressed during prior trastuzumab therapy.

PATIENTS AND METHODS

Women with stage IIIB/IV HER2-overexpressing breast cancer were treated with single-agent lapatinib 1250 or 1500 mg once daily after protocol amendment. Tumor response according to RECIST was assessed every 8 weeks. HER2 expression was assessed in tumor tissue by immunohistochemistry and FISH.

RESULTS

Seventy-eight patients were enrolled in the study. Investigator and independent review response rates [complete response (CR) or partial response (PR)] were 7.7% and 5.1%, and clinical benefit rates (CR, PR, or stable disease for >or=24 weeks) were 14.1% and 9.0%, respectively. Median time to progression was 15.3 weeks by independent review, and median overall survival was 79 weeks. The most common treatment-related adverse events were rash (47%), diarrhea (46%), nausea (31%), and fatigue (18%).

CONCLUSIONS

Single-agent lapatinib has clinical activity with manageable toxic effects in HER2-overexpressing breast cancer that progressed on trastuzumab-containing therapy. Studies of lapatinib-based combination regimens with chemotherapy and other targeted therapies in metastatic and earlier stages of breast cancer are warranted.

Safety and pharmacokinetics (PK) of AMG 706 with panitumumab plus FOLFIRI or FOLFOX for the treatment of patients (pts) with metastatic colorectal cancer (mCRC)

4081

Background: AMG 706 is an oral, investigational multikinase (MKI) inhibitor with antiangiogenic and direct antitumor activity, selectively targeting VEGF, PDGF and Kit receptors. Methods: This is an ongoing phase 1b, open-label, dose-finding study of AMG 706 with panitumumab plus FOLFIRI or FOLFOX in pts with mCRC. Objectives are to establish safety, PK, and the maximum tolerated dose of AMG 706 with this regimen. Pts =18 yrs with mCRC, ECOG 0–1, =1 prior chemotherapy for advanced disease and no prior oral VEGFr MKIs or anti-EGFR therapy, received either FOLFIRI or FOLFOX (based on prior therapy) plus panitumumab (6mg/kg IV day 1 of each 2-wk cycle), and escalating doses of AMG 706 (50, 75, 125mg QD; 75mg BID) given continuously from day 3 of cycle 1. Assessments included dose-limiting toxicities (DLT) during the first 2 cycles and tumor response (every 6–8 wks from wk 6). Results: As of Nov 2006, 45 pts were enrolled and received at least 1 dose of AMG 706 (FOLFIRI/FOLFOX n=33/12); 64% had prior chemotherapy. There were 6 DLTs: FOLFIRI n=4, all grade 3 (diarrhea n=2: 50mg QD, 75mg BID; deep vein thrombosis n=1: 75mg QD; high GI output n=1: 75mg BID); FOLFOX n=2 (all fatigue, grade 3: 50mg QD). Treatment-related adverse events (AE) occurring in =10% of pts included: any AE, FOLFIRI/FOLFOX 88/92% of pts (grade 3, 21/58%); fatigue 55/58% (12/33%), anorexia 24/50% (0/0%), diarrhea 24/33% (0/8%), epistaxis 27/0% (0/0%) and hypertension 15/8% (0/0%). There were no grade 4/5 AEs. 2 cases of cholecystitis (grade 3, n=1) occurred. Preliminary data showed that AMG 706 PK at 50mg QD (FOLFOX) and 50–125mg QD (FOLFIRI) was comparable to data from monotherapy studies at the same dose levels. AMG 706 did not markedly alter the PK profiles of irinotecan or its metabolites. Objective tumor response per RECIST is shown in the table . Conclusions: In this study of pts with mCRC, AMG 706 was tolerable when combined with panitumumab and FOLFIRI or FOLFOX, with little effect on AMG 706 PK.

[Table: see text]

No significant financial relationships to disclose.

Prevalence of insomnia and associated symptoms in patients with cancer

9098

Background: High rates of insomnia have been reported in patients undergoing treatment for cancer. The etiology of insomnia in these patients is unknown, but may be related to psychological factors (anxiety or depression), pain, treatment-related toxicity, or other co-morbid medical conditions. Insomnia has been linked with increased rates of depression, decreased quality of life, and increased fatigue in other patient populations, and is therefore important to understand in the context of cancer. Methods: The Patient Care Monitor (PCM; Supportive Oncology Services, Memphis, TN) is a validated software package assessing oncology-related patient symptoms using a 11- point Likert scale. This instrument is administered routinely to patients at each office visit at most community oncology clinics within the Accelerated Community Oncology Research Network (ACORN). Cross-sectional patient-reported data from 11,445 consecutive patients evaluated at ACORN sites are presented here. Results: The mean age of the sample was 61.5 (±14.2; range 18–95), and 74.3% was female. 25% had received chemotherapy within the prior month. The sample size by tumor site was as follows: breast- 3,316; GU- 2,966; GI- 1,634; hematologic- 1,373; lung- 1,224; head and neck- 501; skin- 321. 55% of the pts reported trouble sleeping, with 26% describing this trouble as moderate or severe. Mean values from patient reported symptoms on the PCM are reported below. 21.9% of patients without insomnia had recent chemotherapy, compared with 27.5% of patients with insomnia who had recent therapy (p<.001). Conclusions: Insomnia occurs commonly in patients with cancer, and is associated with significantly increased fatigue, pain, and depressed mood. Additional research will explore changes in insomnia over the course of treatment, and relate these to possible etiological factors.

[Table: see text]

No significant financial relationships to disclose.