As with all therapeutic proteins, there is a potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.
In patients with various cancers across 15 studies, 1.4% (41/2862) of patients tested positive for antiproduct antibody (APA) at baseline. The incidence of APA development was 3.1% (53/1687) in patients receiving intravenous ziv-aflibercept and 1.7% (19/1134) in patients receiving placebo. Among patients who tested positive for APA and had sufficient samples for further testing, neutralizing antibodies were detected in 17 of 48 ziv-aflibercept-treated patients and in 2 of 40 patients receiving placebo.
The mean free ziv-aflibercept trough concentrations were lower in patients with positive neutralizing antibodies than in the overall population. The impact of neutralizing antibodies on efficacy and safety could not be assessed based on limited available data.
The following adverse reactions have been identified during postapproval use of ZALTRAP. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Musculoskeletal and connective tissue disorders: Osteonecrosis of the jaw
Cardiac disorders: Cardiac failure, ejection fraction decreased
No dedicated drug-drug interaction studies have been conducted for ZALTRAP. No clinically important pharmacokinetic interactions were found between ziv-aflibercept and irinotecan/SN-38 or fluorouracil [see Clinical Pharmacology (12.3)].
Based on findings from animal reproduction studies and its mechanism of action [see Clinical Pharmacology (12.1)] , ZALTRAP can cause fetal harm when administered to pregnant women. There is insufficient data in pregnant women exposed to ZALTRAP to assess the risks. Administration of ziv-aflibercept during the period of organogenesis was embryotoxic and teratogenic in rabbits at exposure levels approximately 0.3 times the human exposure at the 4 mg per kg dose (see Data). Advise pregnant women of the potential risk to a fetus.
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
In pregnant rabbits, administration of ziv-aflibercept during the period of organogenesis resulted in an increase in postimplantation loss and external (including anasarca, umbilical hernia, diaphragmatic hernia and gastroschisis, cleft palate, ectrodactyly, and anal atresia), visceral (heart, great vessels, and arteries), and skeletal fetal malformations (including fused vertebrae, sternebrae, and ribs, supernumerary arches and ribs, and incomplete ossification) at doses greater than or equal to 3 mg per kg, administered once every 3 days (approximately 0.3 times the human exposure at the 4 mg per kg dose based on AUC).
There are no data on the presence of ziv-aflibercept in human milk, or the effects of ziv-aflibercept on the breastfed infant or on milk production. Because of the potential for serious adverse reactions in breastfed infants, advise women not to breastfeed during treatment with ZALTRAP and for 1 month following the last dose.
Verify the pregnancy status in females of reproductive potential prior to initiating ZALTRAP.
Based on data from animal studies and its mechanism of action, ZALTRAP can cause fetal harm when administered to pregnant women [see Use in Specific Populations (8.1)].
Advise female patients of reproductive potential to use effective contraception during treatment with ZALTRAP and for 1 month following the last dose.
Advise female and male patients of reproductive potential that ZALTRAP may impair reproductive function and fertility [see Nonclinical Toxicology (13.1)].
The safety and effectiveness in pediatric patients have not been established. Safety and efficacy were assessed, but not established in a dose-escalation, safety, and tolerability study (NCT00622414) in 21 patients with solid tumors 2 to 21 years of age (median age 12.9). The mean elimination half-life of free ziv-aflibercept determined after the first dose in 8 pediatric patients aged 5 to 17 years was within the range of values previously observed in adults. The maximum tolerated dose based on body weight in these pediatric patients was lower than the dose known to be safe and effective in adults with mCRC.
Juvenile Animal Toxicity Data
Weekly/every-two-weeks intravenous administration of ziv-aflibercept at dose of 3 mg per kg (approximately 0.6 times the human exposure at the 4 mg per kg dose based on AUC) to growing young adult (sexually mature) cynomolgus monkeys for up to 6 months resulted in changes in the bone (effects on growth plate and the axial and appendicular skeleton), nasal cavity (atrophy/loss of the septum and/or turbinates), kidney (glomerulopathy with inflammation), ovary (decreased number of maturing follicles, granulosa cells, and/or theca cells), and adrenal gland (decreased vacuolation with inflammation). In another study in sexually immature cynomolgus monkeys (treated intravenously for 3 months), there were similar effects. The skeletal and nasal cavity effects were not reversible after a post-dosing recovery period.
Of the 611 patients with mCRC, patients treated with ZALTRAP/FOLFIRI, 205 (34%) were 65 years or older, and 33 (5%) were 75 years or older. Elderly patients (≥65 years of age) experienced higher incidences (≥5%) of diarrhea, dizziness, asthenia, weight decrease, and dehydration when compared to younger patients. Monitor elderly patients more closely for diarrhea and dehydration [see Warnings and Precautions (5.9)].
The effect of ZALTRAP on overall survival was similar in patients <65 years old and ≥65 years old who received ZALTRAP/FOLFIRI.
No dosage modification is recommended for patients with renal impairment [see Clinical Pharmacology (12.3)].
No dosage modification is recommended for patients with mild (total bilirubin >1 to 1.5 times upper limit normal [ULN] and any aspartate transaminase [AST]) and moderate (total bilirubin >1.5 to 3 times ULN and any AST) hepatic impairment [see Clinical Pharmacology (12.3)]. ZALTRAP has not been studied in patients with severe hepatic impairment (total bilirubin >3 times ULN and any AST).
Ziv-aflibercept is a vascular endothelial growth factor inhibitor. It is a recombinant fusion protein consisting of Vascular Endothelial Growth Factor (VEGF)-binding portions from the extracellular domains of human VEGF Receptors 1 and 2 fused to the Fc portion of the human IgG1. Ziv-aflibercept is produced by recombinant DNA technology in a Chinese hamster ovary (CHO) K-1 mammalian expression system. Ziv-aflibercept is a dimeric glycoprotein with a protein molecular weight of 97 kilodaltons (kDa) and contains glycosylation, constituting an additional 15% of the total molecular mass, resulting in a total molecular weight of 115 kDa.
ZALTRAP (ziv-aflibercept) injection is a sterile, clear, colorless to pale-yellow, non-pyrogenic, preservative-free, solution for intravenous use. ZALTRAP is supplied in single-dose vials of 100 mg/4 mL and 200 mg/8 mL formulated as 25 mg/mL ziv-aflibercept in polysorbate 20 (1 mg/mL), sodium chloride (5.84 mg/mL), sodium citrate (1.45 mg/mL), sodium phosphate (0.8 mg/mL), and sucrose (200 mg/mL), in Water for Injection, USP, at a pH of 6.2.
Ziv-aflibercept acts as a soluble receptor that binds to human VEGF-A (equilibrium dissociation constant KD of 0.5 pM for VEGF-A165 and 0.36 pM for VEGF-A121 ), to human VEGF-B (KD of 1.92 pM), and to human PlGF (KD of 39 pM for PlGF-2). By binding to these endogenous ligands, ziv-aflibercept can inhibit the binding and activation of their cognate receptors. This inhibition can result in decreased neovascularization and decreased vascular permeability.
In animals, ziv-aflibercept was shown to inhibit the proliferation of endothelial cells, thereby inhibiting the growth of new blood vessels. Ziv-aflibercept inhibited the growth of xenotransplanted colon tumors in mice.
The effect of 6 mg per kg intravenous ZALTRAP every three weeks on QTc interval was evaluated in 87 patients with solid tumors in a randomized, placebo-controlled study. No large changes in the mean QT interval from baseline (i.e., greater than 20 ms as corrected for placebo) based on Fridericia correction method were detected in the study. However, a small increase in the mean QTc interval (i.e., less than 10 ms) cannot be excluded due to limitations of the study design.
Plasma concentrations of free and VEGF-bound ziv-aflibercept were measured using specific enzyme-linked immunosorbent assays (ELISA). Free ziv-aflibercept concentrations appear to exhibit linear pharmacokinetics in the dose range of 2 mg per kg to 9 mg per kg. Steady state concentrations of free ziv-aflibercept were reached by the second dose. The accumulation ratio for free ziv-aflibercept was approximately 1.2 after administration of 4 mg per kg every two weeks.
Following a dose of 4 mg per kg every two weeks administered intravenously, the elimination half-life of free ziv-aflibercept was approximately 6 days (range 4–7 days).
Based on a population pharmacokinetic analysis, age, race, and sex did not have a clinically important effect on the exposure of free ziv-aflibercept. Patients weighing ≥100 kg had a 29% increase in systemic exposure compared to patients weighing 50 to 100 kg.
Patients with hepatic impairment
Based on a population pharmacokinetic analysis which included patients with mild (total bilirubin >1 to 1.5 times ULN and any AST, n=63) and moderate (total bilirubin >1.5 to 3 times ULN and any AST, n=5) hepatic impairment, there was no effect of total bilirubin, AST, and alanine aminotransferase on the clearance of free ziv-aflibercept. There are no data available for patients with severe hepatic impairment (total bilirubin >3 times ULN and any AST).
Patients with renal impairment
Based on a population pharmacokinetic analysis which included patients with mild (CLCR 50–80 mL/min, n=549), moderate (CLCR 30–50 mL/min, n=96), and severe renal impairment (CLCR <30 mL/min, n=5), there was no clinically important effect of creatinine clearance on the clearance of free ziv-aflibercept.
Drug Interaction Studies
No clinically meaningful interaction was found between ziv-aflibercept and irinotecan or fluorouracil based on cross-study comparisons and population pharmacokinetic analyses.
No studies have been conducted to evaluate carcinogenicity or mutagenicity of ziv-aflibercept.
Ziv-aflibercept impaired reproductive function and fertility in monkeys. In a 6-month repeat-dose toxicology study in sexually mature monkeys, ziv-aflibercept inhibited ovarian function and follicular development, as evidenced by: decreased ovary weight, decreased amount of luteal tissue, decreased number of maturing follicles, atrophy of uterine endometrium and myometrium, vaginal atrophy, abrogation of progesterone peaks and menstrual bleeding. Alterations in sperm morphology and decreased sperm motility were present in male monkeys. These effects were observed at all doses tested including the lowest dose tested, 3 mg per kg. Reversibility was observed within 18 weeks after cessation of treatment. Systemic exposure (AUC) with a 3 mg per kg per dose in monkeys was approximately 0.6 times the AUC in patients at the 4 mg per kg dose.
Repeated administration of ziv-aflibercept resulted in a delay in wound healing in rabbits. In full-thickness excisional and incisional skin wound models, ziv-aflibercept administration reduced fibrous response, neovascularization, epidermal hyperplasia/re-epithelialization, and tensile strength.
The efficacy of ZALTRAP was evaluated in VELOUR (NCT00561470), a randomized (1:1), double-blind, placebo-controlled study in patients with mCRC who are resistant to or have progressed during or within 6 months of receiving oxaliplatin-based combination chemotherapy, with or without prior bevacizumab. Patients were randomized to receive either ZALTRAP 4 mg per kg intravenously over 1 hour on day 1 or placebo in combination with FOLFIRI (irinotecan 180 mg/m2 intravenously over 90 minutes and leucovorin [dl racemic] 400 mg/m2 intravenously over 2 hours at the same time on day 1 using a Y-line, followed by fluorouracil 400 mg/m2 as an intravenous bolus and then by fluorouracil 2400 mg/m2 as a continuous intravenous infusion over 46 hours). The treatment cycles on both arms were repeated every 2 weeks. Patients were treated until disease progression or unacceptable toxicity. Randomization was stratified by the Eastern Cooperative Oncology Group performance status (PS) (0 versus 1 versus 2) and according to prior therapy with bevacizumab (yes or no). The major efficacy outcome measure was overall survival (OS). Additional efficacy outcome measures were progression-free survival (PFS) and overall response rate (ORR).
Demographics characteristics were similar between treatment arms. A total of 1226 patients were randomized, 612 to the ZALTRAP arm and 614 to the placebo arm. The median age was 61 years, 59% were men, 87% were White, 7% were Asian, 3.5% were Black, and 98% had a baseline ECOG PS of 0 or 1. Among the 1226 randomized patients, 89% and 90% of patients treated with placebo/FOLFIRI and ZALTRAP/FOLFIRI, respectively, received prior oxaliplatin-based combination chemotherapy in the metastatic/advanced setting. A total of 346 patients (28%) received bevacizumab in combination with the prior oxaliplatin-based treatment.
Efficacy results are summarized in Figure 1 and Table 2.
Figure 1: Kaplan-Meier Curves of Overall Survival for VELOUR
|Number of deaths, n (%)||403 (65.8%)||460 (74.9%)|
|Median overall survival (95% CI) (months)||13.50 (12.52, 14.95)||12.06 (11.07, 13.08)|
|Stratified Hazard ratio (95% CI)||0.817 (0.714, 0.935)|
|Stratified Log-Rank test p-value||0.0032|
|Progression Free Survival (PFS)*|
|Number of events, n (%)||393 (64.2%)||454 (73.9%)|
|Median PFS (95% CI) (months)||6.90 (6.51, 7.20)||4.67 (4.21, 5.36)|
|Stratified Hazard ratio (95% CI)||0.758 (0.661, 0.869)|
|Stratified Log-Rank test p-value †||0.00007|
|Overall Response Rate (ORR)|
|ORR (CR+PR) (95% CI)‡||19.8% (16.4%, 23.2%)||11.1% (8.5%, 13.8%)|
|Stratified Cochran-Mantel-Haenszel test p-value||0.0001|
Planned subgroup analyses for overall survival based on stratification factors at randomization yielded an HR of 0.86 (95% CI: 0.68, 1.1) in patients who received prior bevacizumab and an HR of 0.79 (95% CI: 0.67, 0.93) in patients without prior bevacizumab exposure.
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