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 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.