Source: FDA, National Drug Code (US) Revision Year: 2023
Efbemalenograstim alfa-vuxw is a colony-stimulating factor that acts on hematopoietic cells by binding to specific cell surface receptors, thereby stimulating proliferation, differentiation, commitment, and end cell functional activation.
Over the tested dose range of 30 to 360 μg/kg in healthy adult males, neutrophils generally increased in a dose-dependent manner; however, the effect on neutrophils plateaued at the top two doses of 240 and 360 μg/kg.
In patients with breast cancer given EC chemotherapy, in cycle 1, median ANC peaked on Day 4 (about 24 hours after efbemalenograstim alfa-vuxw administration) for the 240 and 320 μg/kg doses, declined to nadir on Days 8–9, and then recovered to a count of 2.0 × 109/L and higher by Day 11. The ANC levels in cycles 2, 3, and 4 tended to be higher than those observed in cycle 1.
In patients with breast cancer given TAC chemotherapy, in cycle 1, median ANC peaked on Day 3 (about 24 hours after efbemalenograstim alfa-vuxw administration) in cycle 1 and 3, reached nadir on Day 8, and recovered to 2.0 × 109/L on Days 9 and 10 for the 320 μg/kg and 240 μg/kg doses, respectively. Mean ANC nadir was higher with 320 μg/kg compared to 240 μg/kg in both cycle 1 (0.75 × 109/L and 0.29 × 109/L, respectively), and cycle 3 (1.19 × 109/L and 0.57 × 109/L, respectively).
The pharmacokinetics of efbemalenograstim alfa-vuxw was studied in female patients with breast cancer and healthy male subjects. Efbemalenograstim alfa-vuxw exhibited nonlinear and time-dependent pharmacokinetics over the dose range of 30 to 360 μg/kg. At the approved recommended dose in healthy subjects, the mean (CV) Cmax was 1202 ng/mL (56), and the AUC0-inf was 76357 h*ng/mL (65%). At the approved recommended dose in patients with breast cancer, the geometric mean (CV%) Cmax was 1085 ng/mL (92%) in Cycle 1 and 525 ng/mL (163%) in Cycle 3; the geometric mean (CV%) AUC0-inf was 54858 h*ng/mL (110%) in Cycle 1 and 26217 h*ng/mL (167%) in Cycle 3.
The median tmax of efbemalenograstim alfa-vuxw administered as 80 to 320 μg/kg in female patients with breast cancer receiving EC chemotherapy ranged from 24 hours to 48 hours in Cycle 1 and 9 to 30 hours in Cycle 3. The median tmax of efbemalenograstim alfa-vuxw administered as 240 to 320 μg/kg in female participants with breast cancer receiving TAC chemotherapy was 36 hours in Cycle 1 and ranged from 24 to 30 hours in Cycle 3.
The geometric mean (CV%) apparent volume of distribution of efbemalenograstim alfa-vuxw was 18.8 L (257%) in Cycle 1 and 40.7 L (387%) in Cycle 3 in female patients with breast cancer.
The geometric mean (CV%) apparent clearance of efbemalenograstim alfa-vuxw was 0.36 L/h (110%) in Cycle 1 and 0.76 L/h (167%) in Cycle 3. The geometric mean (CV%) elimination half-life of efbemalenograstim alfa-vuxw was 35.6 h (108%) in Cycle 1 and 36.9 h (120%) in Cycle 3. Neutrophil receptor binding is an important component of the clearance of efbemalenograstim alfa-vuxw, and serum clearance is directly related to the number of neutrophils.
Efbemalenograstim alfa-vuxw is expected to be metabolized into small peptides by catabolic pathways.
No clinically significant differences were observed based on age (20 to 83 years) or body weight (40 to 137 kg) [see Use in Specific Populations (8.5)]. The impact of sex, race/ethnicity, renal impairment, hepatic impairment, and pregnancy on the pharmacokinetics of efbemalenograstim alfa-vuxw are unknown.
No carcinogenicity or mutagenesis studies have been conducted with efbemalenograstim alfa-vuxw.
Efbemalenograstim alfa did not affect reproductive performance or fertility in male or female rats at cumulative weekly doses approximately 2.2 times higher than the recommended human dose (based on body surface area).
The efficacy of RYZNEUTA to decrease the incidence of infection, as manifested by febrile neutropenia, in patients with nonmyeloid malignancies receiving myelosuppressive anti-cancer drugs was evaluated in two randomized, controlled studies.
Study GC-627-04 [NCT02872103] was a randomized, double-blind, placebo-controlled study that employed doxorubicin 60 mg/m² and docetaxel 75 mg/m² administered every 21 days for up to 4 cycles for the treatment of metastatic or non-metastatic breast cancer. In this study, 122 patients were randomized to receive a single subcutaneous injection of RYZNEUTA (20 mg) or placebo on day 2 of chemotherapy cycle 1. All patients received RYZNEUTA (20 mg) on day 2 of chemotherapy cycles 2-4. The patients were 30 to 69 years of age and all female. The race was 99% Caucasian, and 1% Black. The ethnicity was 2% Hispanic or Latino.
Efficacy was based upon the mean duration of severe (Grade 4) neutropenia in cycle 1 which was lower for RYZNEUTA-treated patients as compared to placebo-treated patients (LS mean: 1.4 days versus 4.3 days, respectively, p<0.001 [95% CI: 2.4, 3.5]). The incidence of febrile neutropenia (defined as temperature ≥38.3℃, or >38.0℃ sustained for at least 1 hour, and ANC < 0.5 × 109) was also lower for RYZNEUTA-treated patients compared to placebo-treated patients in cycle 1 (4.8% versus 25.6%, respectively, p=0.0016; 20.8% difference [95% CI: 1.8%, 38.8%].
Study GC-627-05 [NCT03252431] was a randomized, active-controlled study that compared RYZNEUTA to pegfilgrastim. Study GC-627-05 employed docetaxel 75 mg/m² and cyclophosphamide 600 mg/m² administered every 21 days for up to 4 cycles for the treatment of non-metastatic breast cancer. In this study, 393 patients were randomized to receive a single subcutaneous injection of RYZNEUTA (20 mg) or pegfilgrastim (6 mg) on day 2 of each chemotherapy cycle. The patients were 26 to 83 years of age and all female and Caucasian. The ethnicity was 0.3% Hispanic or Latino.
The study demonstrated that the mean days of severe (Grade 4) neutropenia of RYZNEUTA-treated patients did not exceed that of pegfilgrastim-treated patients by more than 0.6 days in cycle 1 of chemotherapy. The mean days of severe neutropenia in cycle 1 were 0.2 days in both the RYZNEUTA and pegfilgrastim arms (difference in means 0.0 days [95% CI -0.1, 0.1]).
Subgroup analyses of treatment effect were not useful due to small subgroup sizes.
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