Abstract PD6-03: Distribution of microsatellite instability, tumor mutational load, and PD-L1 status in molecularly profiled invasive breast cancer

Background: Recent data indicate a promising response to immune check point blockade (ICB) in patients with breast cancer. Pembrolizumab, a humanized monoclonal antibody against programmed death 1 (PD-1) receptor and one of several ICB agents in development, was given an FDA approval for all MSI (microsatellite instability)-high solid tumors. MSI incidence in breast cancer is not fully elucidated. Other biomarkers being explored in possible relationship to ICB activity include PD-1 ligand (PD-L1) status and tumor mutational load (TML). In this study, we aimed to explore the incidence of these biomarkers in invasive breast cancers.

Methods: A retrospective data analysis of patients profiled by commercial next-generation sequencing (NGS) at Caris Life Sciences was performed. MSI results were either high, stable, or equivocal. MSI was calculated by comparing repeat-insertions or deletions across over 7,000 microsatellite sequences in the patient sample to the hg19 reference genome. Samples with repeat variances in more than 45 microsatellites were classified as MSI-High PD-L1 expression was evaluated using immunohistochemical analysis (IHC), with clone SP-142 (Roche Diagnostics). A sample was considered positive if there was >5% membranous staining of tumor cells. Tumor mutational load was calculated as a total number of non-synonymous somatic mutations identified per megabase of the genome coding area with high being greater than or equal to 17.

Results: A total of 9,627 breast cancer cases were queried from the Caris Life Sciences database. The mean age (±SD) was 56.8 ± 12.4 years (range 20-90). The tumor distribution was 60.7% hormone receptor (HR) positive (ER and/or PR) and HER2 negative, 9.5% HER2 positive (with HR negative or positive), and 29.8% triple negative (negative for ER, PR and HER2). Of all cases, there were 5,203 tested for PD-L1 status, 354 (6.8%, 95% CI 6.2-7.5%) were positive. Of 1,440 tumors tested for MSI status, 15 (1.04%, 95% CI 0.58-1.71%) were either high (8) or equivocal (7), the rest were MSI-low. Tumor mutational load (TML) was available on 1,766 tumors, of which 55 (3.1%, 95% CI 2.4-4.0%) were high. Seven out of the 8 MSI-high tumors were also TML-high. Four out of the 8 MSI-high breast cancers were triple negative.

Conclusion: In this large dataset of molecularly profiled breast cancer, MSI was observed in about 1% of the breast tumors tested. Overall, modest positivity of TML, PD-L1, and MSI of all invasive breast cancers was observed. The percentage of patients that had at least one of these biomarkers that may confer responsiveness to ICB is planned and will be further stratified by subtype. MSI-high breast cancers mostly overlapped with those that were TML-high. Future research is needed to show the clinical utility of these biomarkers in response to ICB. Updated data will be presented.

Citation Format: Obeid E, Ellerbrock A, Handorf E, Goldstein L, Gatalica Z, Arguello D, Swain SM, Isaacs C, Vacirca J, Tan A, Schwartzberg L. Distribution of microsatellite instability, tumor mutational load, and PD-L1 status in molecularly profiled invasive breast cancer [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 PD6-03.

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 OT1-02-10: A phase 2 study of poziotinib in patients with HER2-positive metastatic breast cancer (MBC) who have received prior HER2 regimens for MBC

Background: Poziotinib is a novel, oral, quinazoline-based pan-HER inhibitor that irreversibly blocks signaling through the epidermal growth factor receptor (EGFR) family of tyrosine-kinase receptors, including EGFR (HER1/ErbB1/EGFR), HER2 (ErbB2), and HER4 (ErbB4), as well as HER receptor mutations. This, in turn, leads to inhibition of the proliferation of tumor cells that overexpress these receptors. It is well established that breast cancers are associated with a mutation in, or overexpression of, members of the EGFR receptor family. The primary objective of this Phase 2 study is to evaluate the Objective Response Rate (ORR) of poziotinib in patients with human epidermal growth factor receptor 2 (HER2)-positive MBC. The secondary efficacy variables are Progression-Free Survival (PFS), Disease Control Rate (DCR), Overall Survival (OS), and Time to Progression (TTP).

Trial Design: This is a Phase 2, open-label, multicenter study to evaluate the efficacy, safety and tolerability of poziotinib in patients with HER2-positive MBC who have received at least 2 prior HER2- directed treatment regimens. Each treatment cycle is 21 days in duration. During each cycle, eligible patients receive 24 mg of poziotinib orally (as three 8-mg tablets) once daily for 14 days, followed by a 7 day treatment-free period.

Eligibility Criteria: Eligible patients are at least 18 years of age, have confirmed HER2 overexpression, adequate hematologic, renal and hepatic function, and have received at least 2 prior HER2-directed therapy regimens, including trastuzumab and trastuzumab emtansine (TDM-1). Patients are excluded if they have prior exposure to poziotinib, a history of congestive heart failure, left ventricular ejection fraction <50%, unable to take oral medications, or have conditions that cause malabsorption. A 30 day wash out period from previous chemotherapeutic or radiation therapies is required.

Statistical Methods: The purpose of this study is to evaluate the efficacy of poziotinib compared to the efficacy of other standard HER2-positive breast cancer treatments as reported in the literature. The ORR will be analyzed descriptively along with the 95% CI. The secondary efficacy variables will be analyzed descriptively.

Target Accrual: Approximately 70 patients. Enrollment began February 2016.

Contact Information: For more information or to refer a patient,

email: spi-poz-201@sppirx.com or fax: 1-949-398-9711.

Citation Format: Lathrop K, Lucas J, Vacirca JL, Bhat G, Choi MR, Naughton M. A phase 2 study of poziotinib in patients with HER2-positive metastatic breast cancer (MBC) who have received prior HER2 regimens for MBC [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 OT1-02-10.

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 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 OT3-02-13: Randomized phase 3 study of a novel, long-acting G-CSF (SPI-2012) versus pegfilgrastim in the management of chemotherapy-induced neutropenia in early-stage breast cancer patients receiving docetaxel and cyclophosphamide (TC) (ADVANCE study)

Background: SPI-2012 is a distinct biologic that uses the innovative, proprietary long-acting protein/peptide discovery technology (LAPSCOVERY™) to enhance the activity of G-CSF. SPI-2012 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, more potent, longer-acting G-CSF with a potentially unique distribution to areas rich in Fc receptors. The primary endpoint of this Phase 3 study is to compare the efficacy of a single dose of SPI-2012 with pegfilgrastim in patients with early-stage breast cancer (ESBC) receiving TC chemotherapy, as measured by the Duration of Severe Neutropenia (DSN) in Cycle 1. Key secondary objectives include the comparison of SPI-2012 with pegfilgrastim during Cycle 1 in: Time to Absolute Neutrophil Count (ANC) Recovery; Depth of ANC Nadir and Incidence of Febrile Neutropenia. Safety and pharmacokinetics will also be assessed.

Trial Design: This is a randomized, open-label, active-controlled, multicenter study comparing the efficacy and safety of SPI-2012 to pegfilgrastim. Patients (n=506) will be randomized in a 1:1 ratio to receive either SPI-2012 (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 hrs after chemotherapy.

Eligibility Criteria: This study will enroll histologically confirmed ESBC patients who are eligible to receive adjuvant or neoadjuvant TC chemotherapy and 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 the study is to demonstrate non-inferiority of SPI-2012 to pegfilgrastim. For the Primary Efficacy Analysis, the mean DSN in Cycle 1 will be compared between the SPI-2012 and pegfilgrastim treatment arms. A 2-sided 95% confidence interval (CI) of the difference between the mean DSN of the SPI-2012 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 506 pts.

Citation Format: Schwartzberg L, Vacirca JL, Hager SJ, Adoo CS, Ibrahim EN, Bhat G, Choi MR, Allen LF, Tedesco KL, Agajanian R. Randomized phase 3 study of a novel, long-acting G-CSF (SPI-2012) 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 Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-02-13.

Abstract P1-10-07: Phase 3 comparison of APF530 versus ondansetron, each in a guideline-recommended 3-drug regimen for prevention of chemotherapy-induced nausea and vomiting due to anthracycline + cyclophosphamide (AC)–based highly emetogenic chemotherapy (HEC) regimens: A post hoc subgroup analysis of the MAGIC trial

Background:Managing delayed chemotherapy-induced nausea and vomiting (CINV) associated with HEC is an unmet need. AC-based HEC is often administered to breast cancer patients (pts), a mostly female, high-CINV-risk population. APF530, an extended-release formulation of granisetron, demonstrated superior complete response (CR; no emesis [vomiting, retching] + no rescue medication use) in delayed-phase (>24-120 h) CINV with HEC (ASCO criteria) vs ondansetron (Ond) (65% vs 57%, P=0.014), each combined with a neurokinin-1 antagonist and dexamethasone (Dex) (NCT02106494). This post hoc analysis evaluated efficacy and safety of APF530 in pts receiving AC-based therapy.

Methods: In this randomized, double-blind, multicenter trial, pts scheduled to receive single-day HEC were stratified by cisplatin ≥50 mg/m2 yes/no and randomized 1:1 to APF530 500 mg SC (granisetron 10 mg) or Ond 0.15 mg/kg IV. Pts received concomitant Dex 12 mg IV and fosaprepitant 150 mg IV on day 1 and oral Dex on days 2-4. The primary end point was CR in the delayed phase. Secondary and other end points included CR in acute (0-24 h) and overall (0-120 h) phases, and complete control (CC; CR and no more than mild nausea) and total response (TR; CR and no nausea) in acute, delayed, and overall phases. Rates were compared using 95% confidence intervals (CIs) for treatment differences; post hoc analysis was not powered to detect treatment differences in the AC subgroup. Safety assessments included adverse events (AEs), injection-site reactions (ISRs), laboratory parameters, and vital signs.

Results: A total of 589/902 pts (65%) in the modified intent-to-treat population received AC-based HEC (APF530 291, Ond 298). Baseline demographics were balanced between treatment arms. The majority of pts in the AC subgroup were female (APF530 99%, Ond 98%). Delayed-phase CR was higher with APF530 vs Ond, approaching statistical significance (APF530 64%, Ond 56%; P=0.062) in the AC subgroup, similar to the benefit seen in the larger study. No appreciable benefit of APF530 vs Ond was observed in the acute phase, and trends favorable to APF530 were observed in the overall phase (Table). APF530 was well tolerated. Most AEs were ISRs, generally mild or moderate, and resolved by end of study.

Phase, n (%)APF530OndansetronTreatment DifferenceN=291N=298(95% CI), %Complete responseDelayed185 (64)167 (56)8 (-0.4, 15.4)Overall163 (56)153 (51)5 (-3.4, 12.7)Acute205 (70)204 (69)1 (-5.4, 9.4)Complete controlDelayed171 (59)156 (52)7 (-1.6, 14.4)Overall149 (51)143 (48)3 (-4.9, 11.3 )Acute193 (66)191 (64)2 (-5.5, 9.9)Total responseDelayed119 (41)107 (36)5 (-2.9, 12.8)Overall100 (34)94 (32)2 (-4.8, 10.4)Acute164 (56)173 (58)-2 (-9.7, 6.3)

Conclusions: APF530 demonstrated an apparent clinical benefit in delayed-phase CR in pts receiving AC-based HEC, concordant with the statistically significant benefit seen in the overall study population. Prevention of CINV in this patient population continues to be a treatment challenge and further investigation is needed.

Citation Format: Schnadig I, Agajanian R, Dakhil S, Taylor C, Wilks S, Cooper W, Mosier M, Payne Y, Klepper M, Vacirca J. Phase 3 comparison of APF530 versus ondansetron, each in a guideline-recommended 3-drug regimen for prevention of chemotherapy-induced nausea and vomiting due to anthracycline + cyclophosphamide (AC)–based highly emetogenic chemotherapy (HEC) regimens: A post hoc subgroup analysis of the MAGIC trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-07.

Abstract P1-10-05: Randomized phase 2, open-label, dose-ranging study of a novel, long-acting G-CSF (SPI-2012) or pegfilgrastim for the management of neutropenia in patients with breast cancer (BC) treated with (Neo) adjuvant chemotherapy with docetaxel + cyclophosphamide (TC)

Background: SPI-2012 is a distinct biologic that uses the innovative proprietary long-acting protein/peptide discovery technology (LAPSCOVERY™) to enhance the activity of G-CSF. SPI-2012 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, more potent, longer-acting G-CSF with a potentially unique distribution to areas rich in Fc receptors. To assess the effect of SPI-2012 in supporting patients with breast cancer receiving myelosuppressive chemotherapy with TC, we conducted a randomized Phase 2 study of 3 SPI-2012 doses versus pegfilgrastim.

Methods: This was an open-label, global, multicenter, dose-ranging study designed to compare the safety and efficacy of SPI-2012 relative to a fixed, standard dose of pegfilgrastim as a concurrent active control. The study included 4 treatment arms: 3 dose levels of SPI-2012 (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 in patients with BC who received adjuvant or neoadjuvant TC chemotherapy.

Results: A total of 147 evaluable patients were enrolled. Patient and tumor characteristics were comparable across all 4 treatment arms. Mean age was 58.2 years (range 32 to 77 years); most patients were <65 years (68%), female (98%) and white (95%). The study met its primary endpoint with DSN in patients treated in the 135 µg/kg and 270 µg/kg SPI-2012 treatment arms in Cycle 1 showing non-inferiority to the DSN in patients treated with pegfilgrastim (p=0.002 and p<0.001, respectively). In addition, superiority was demonstrated in patients treated with 270 µg/kg SPI-2012 compared to pegfilgrastim (p=0.023). Non-inferiority in DSN was also observed in Cycles 2 to 4 in both the 135 µg/kg and 270 µg/kg SPI-2012 treatment arms compared to pegfilgrastim.

Duration of Severe Neutropenia in Cycle 1 of TC chemotherapy by Treatment Arm  45 μg/kg SPI-2012 (N=39) 135 μg/kg SPI-2012 (N=36) 270 μg/kg SPI-2012 (N=36)Pegfilgrastim (N=36)DSN Mean (SD)(days)1.03 (1.5)0.44 (1.3)0.03 (0.2)0.31 (0.8)Difference with pegfilgrastim0.720.14-0.28NANon-inferiority p-value0.2960.002<0.001NASuperiority p-value0.0060.5280.023NASD=Standard Deviation; NA=Not Applicable

The common treatment-emergent adverse events observed in ≥20% of patients were similar across all 4 study arms with similar or lower incidence in the SPI-2012 treatment arms, and included fatigue, nausea, alopecia, diarrhea, and bone pain.

Conclusions: All doses of SPI-2012 administered in this Phase 2 study were well tolerated, and no new or significant dose-related toxicities were observed. Most reported adverse events were mild and similar to those previously reported in clinical trials with filgrastim and pegfilgrastim in patients receiving myelosuppressive chemotherapy. In Cycle 1, the 135 µg/kg dose of SPI-2012 was non-inferior compared to pegfilgrastim, and the 270 µg/kg dose was superior in terms of DSN. Additional efficacy and safety data for SPI-2012 will be collected in planned Phase 3 clinical trials.

Citation Format: Vacirca JL, Chan A, Mezei K, Adoo CS, Papai Z, McGregor K, Okera M, Horvath Z, Landherr L, Hanslik J, Hager SJ, Ibrahim EN, Ghazal H, Rostom M, Bhat G, Choi MR, Allen LF, Tedesco KL, Agajanian R, Lang I. Randomized phase 2, open-label, dose-ranging study of a novel, long-acting G-CSF (SPI-2012) or pegfilgrastim for the management of neutropenia in patients with breast cancer (BC) treated with (Neo) adjuvant chemotherapy with docetaxel + cyclophosphamide (TC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-05.

Intra-carotid chemo (ICC) followed by radiation (RT) with concomitant temozolamide (TMZ) and subsequent maintenance TMZ therapy in patients (pts) with glioblastoma multiforme (GBM)

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Background: Glioblastoma multiforme is one of the most resistant malignant tumors. Surgery provides only temporary, palliative relief. Radiation therapy affords additional, though short, benefit. Systemic, intravenous and/or oral chemotherapy with nitrosoureas and TMZ, increases survival only slightly. Median survival (MS) after all these modalities incorporated remains unimpressive, less than 14 months. Intracarotid chemotherapy with cisplatin and VP-16, a standard treatment at Stony Brook University Hospital since 1999, prior to RT, results in MS of 20 months. A year later we added TMZ as a part of standard treatment with or without ICC in patients with GBM. Provided here is a retrospective analysis of the treatment consisting of surgery, ICC, RT with concomitant TMZ followed by 2 years of TMZ maintenance. Methods: Fifteen patients with pathologically confirmed, newly diagnosed GBM were treated from year 2000 to 2005; 11 men; median age 53 (range 25-68); 80% with PS over 70. They underwent a surgical procedure (5 near total) followed by ICC with cisplatin 60 mg/m2 and VP-16 40 mg/m2 every 3 weeks for total of 3 cycles. Subsequently they received TMZ 75 mg/m2/day orally, concomitantly with RT 6120–6300 cGY, followed a month later by maintenance therapy with TMZ 200 mg/m2/ daily for 5 days out of each month for 2 years or until progression. Results: Fourteen pts.are being evaluated (one too early), all have survived at least 12 months.One-year PFS is 79%. Median time to progression is 19.5 months; MS is 25 months with a range of 12-48 months. Toxicity is limited to nausea and vomiting mainly grade 1-2; only 1 patient experienced grade 3 vomiting with subsequent TMZ maintenance dose reduction by about 10%. Conclusions: Surgery followed by ICC, then combination of RT + TMZ followed by maintenance TMZ therapy seems to be more effective in improving patient survival than surgery, ICC and RT as reported previously by us in pts with GBM (Cancer 2000; 10:2350–6). This treatment has been well tolerated.

No significant financial relationships to disclose.