AKYNZEO

The recommended dosages of AKYNZEO and dexamethasone in adults for the prevention of nausea and vomiting associated with administration of emetogenic chemotherapy are shown in Table 1.

AKYNZEO capsules can be taken with or without food.

AKYNZEO injection is supplied as either a Ready-to-Use (with hanger) vial or a To-be-Diluted vial.

AKYNZEO injection (Ready-to-Use; with hanger)
See Table 2 for preparation instructions of AKYNZEO injection (Ready-to-Use) for intravenous infusion. AKYNZEO injection (Ready-to-Use) does not require dilution prior to administration.

AKYNZEO injection (Ready-to-Use) contains no antimicrobial preservatives and is intended for single use only.

Compatibility
AKYNZEO injection (Ready-to-Use) is compatible with intravenous dexamethasone sodium phosphate which can be infused simultaneously. Do not add dexamethasone sodium phosphate to the AKYNZEO injection (Ready-to-Use) vial.

Stability and Storage
Use immediately once the stopper is punctured.

AKYNZEO Injection (To-be-Diluted)
See Table 3 for preparation instructions of AKYNZEO injection (To-be-Diluted) for intravenous infusion with dilution.

AKYNZEO injection (To-be-Diluted) contains no antimicrobial preservatives and is intended for single use only.

Compatibility

AKYNZEO injection (To-be-Diluted) is compatible with intravenous dexamethasone sodium phosphate which can be added to the infusion bag containing AKYNZEO solution or infused simultaneously.

Stability and Storage

The total time from dilution to the start of the infusion, with or without intravenous dexamethasone sodium phosphate, should not exceed 24 hours.

Store the final diluted solution at room temperature, 20ºC to 25ºC (68Fº to 77ºF).

See Table 4 for preparation instructions of AKYZNEO for injection. AKYNZEO for injection requires dilution prior to administration.

AKYNZEO for injection contains no antimicrobial preservatives, is intended for single use only.

Compatibility

AKYNZEO for injection is compatible with intravenous dexamethasone sodium phosphate which can be added to the infusion bag containing AKYNZEO solution or infused simultaneously.

Stability and Storage

The total time from reconstitution to the start of the infusion, with or without intravenous dexamethasone sodium phosphate, should not exceed 24 hours.

Store the reconstituted solution and the final diluted solution at room temperature, 20ºC to 25ºC (68ºF to 77ºF).

AKYNZEO for injection, AKYNZEO injection (Ready-to-Use) and AKYNZEO injection (To-be-Diluted) are incompatible with any solution containing divalent cations (e.g., calcium, magnesium), including Lactated Ringer’s injection and Hartmann's Solution.

Limited data are available on the compatibility of AKYNZEO for injection, AKYNZEO injection (Ready-to-Use), and AKYNZEO injection (To-be-Diluted) with other intravenous substances, additives, or other medications with the exception of intravenous dexamethasone sodium phosphate [see Dosage and Administration ( 2.2 , 2.3 ) ] and they should not be added to the AKYNZEO solution or infused simultaneously. If the same intravenous line is used for sequential infusion of several different drugs, flush the line before and after infusion of AKYNZEO solution with 0.9% Sodium Chloride Injection, USP.

Hypersensitivity reactions, including anaphylaxis, have been reported in patients treated with palonosetron, one of the components of AKYNZEO, with or without known hypersensitivity to other 5-HT₃ receptor antagonists.

The development of serotonin syndrome has been reported with 5-HT₃ receptor antagonists. Most reports have been associated with concomitant use of serotonergic drugs (e.g., selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors, mirtazapine, fentanyl, lithium, tramadol, and intravenous methylene blue). Some of the reported cases were fatal. Serotonin syndrome occurring with overdose of another 5-HT₃ receptor antagonist alone has also been reported. The majority of reports of serotonin syndrome related to 5-HT₃ receptor antagonist use occurred in a post-anesthesia care unit or an infusion center. 

Symptoms associated with serotonin syndrome may include the following combination of signs and symptoms: mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, and hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, and incoordination), seizures, with or without gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).  Patients should be monitored for the emergence of serotonin syndrome, especially with concomitant use of AKYNZEO and other serotonergic drugs. If symptoms of serotonin syndrome occur, discontinue AKYNZEO and initiate supportive treatment. Patients should be informed of the increased risk of serotonin syndrome, especially if AKYNZEO is used concomitantly with other serotonergic drugs [see Drug Interactions ( 7.3)].

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

AKYNZEO Capsules

The overall safety of AKYNZEO capsules was evaluated in 1538 cancer patients and healthy subjects in clinical trials. The data described below reflect exposure to AKYNZEO in 1169 cancer patients, receiving at least one cycle of cancer chemotherapy in 3 active-controlled trials [see Clinical Studies ( 14 .1)], including 782 exposed to AKYNZEO for at least 4 cycles and 321 exposed for at least 6 cycles, up to a maximum of 12 cycles of chemotherapy. The median age was 55, 79% were female, 83% were White, 13% were Asian, and 4% were Hispanic. All patients received a single oral dose of AKYNZEO 1 hour prior to the start of each chemotherapy cycle. In all studies, dexamethasone was co-administered with AKYNZEO [see Clinical Studies ( 14.1), Table 16 and Table 18 ].

Cisplatin Based Highly Emetogenic Chemotherapy

In a single-cycle study of patients receiving cisplatin based highly emetogenic chemotherapy, 136 patients were treated with AKYNZEO. Table 5 shows adverse reactions reported at an incidence of at least 3% and for which the AKYNZEO rate exceeded palonosetron alone.

Anthracyclines and Cyclophosphamide Based Chemotherapy

In a study of patients receiving anthracycline and cyclophosphamide based chemotherapy, 725 patients were treated with AKYNZEO capsules during Cycle 1, and 635 of these patients continued for up to 8 cycles in a multiple-cycle extension. Table 6 shows adverse reactions reported at an incidence of at least 3% and for which the AKYNZEO capsules rate exceeded palonosetron alone during Cycle 1. The adverse reaction profile in subsequent cycles was similar to that observed in Cycle 1.

In addition to the adverse reactions shown above, there were reports of concomitant elevations of transaminases greater than 3 times the upper limit of normal and total bilirubin in both arms of the two trials that compared AKYNZEO capsules to oral palonosetron, and the frequency of these elevations was comparable between treatment groups. See Table 7.

In a multi-cycle safety study of 412 patients, the safety profile of AKYNZEO capsules (n = 308) was comparable to aprepitant and palonosetron (n = 104) in patients undergoing initial and repeat cycles (median 5 cycles, range of 1-14 cycles) of chemotherapy, including carboplatin, cisplatin, oxaliplatin, and doxorubicin regimens. There were no reports of concomitant elevations of transaminases greater than 3 times the upper limit of normal and total bilirubin in this study in either arm.

In a randomized, clinical non-inferiority study, that compared oral palonosetron 0.5 mg to intravenous palonosetron 0.25 mg in cancer patients scheduled to receive highly emetogenic cisplatin (greater than or equal to 70 mg/m²) based chemotherapy, there were two patients (0.5%; 2/369) in the intravenous palonosetron arm who had concomitant elevations of transaminases and total bilirubin. Neither experienced transaminase elevations greater than 10 times the upper limit of normal. 

AKYNZEO for Injection

The safety of AKYNZEO for injection was evaluated in 203 patients in an active-controlled multi-cycle (median 4 cycles, range of 1-4 cycles) safety clinical study in patients receiving HEC regimens, not including anthracycline plus cyclophosphamide, (e.g., cisplatin, cyclophosphamide, carmustine, dacarbazine and mechlorethamine) compared to 201 patients receiving AKYNZEO capsules (NCT02517021). The median age was 60 years, 46% were female, 99.5 % were White, 0.3% were Asian, and 0.3% were Hispanic. All patients received a single dose of AKYNZEO for injection 30 minutes prior to the start of each chemotherapy cycle; dexamethasone was co-administered with AKYNZEO. The safety profile of AKYNZEO for injection was generally similar to that seen with AKYNZEO capsules.

Interaction with CYP3A4 Substrates

Netupitant is a moderate inhibitor of CYP3A4. 

AKYNZEO should be used with caution in patients receiving concomitant medications that are primarily metabolized through CYP3A4. A single oral dose of netupitant 300 mg significantly inhibits CYP3A4 for 6 days. Avoid concomitant use of drugs that are CYP3A4 substrates for one week, if feasible.  If not avoidable, consider dose reduction of CYP3A4 substrates.

Dexamethasone

A single oral dose of netupitant 300 mg or a single fosnetupitant infusion of 235 mg increased the systemic exposure of concomitant dexamethasone more than 2-fold on Days 2 and 4. Administer a reduced dose of dexamethasone with AKYNZEO [see Dosage and Administration ( 2.1), Clinical Pharmacology ( 12.3 )].

Midazolam

When administered with netupitant, the systemic exposure to midazolam was significantly increased. Consider the potential effects of increased plasma concentrations of midazolam or other benzodiazepines metabolized via CYP3A4 (alprazolam, triazolam) when administering these drugs with AKYNZEO [see Clinical Pharmacology ( 12.3 )].

Chemotherapeutic Agents

The systemic exposure of chemotherapy agents metabolized by CYP3A4 can increase when administered with AKYNZEO. Chemotherapy agents that are known to be metabolized by CYP3A4 include docetaxel, paclitaxel, etoposide, irinotecan, cyclophosphamide, ifosfamide, imatinib, vinorelbine, vinblastine, and vincristine [see Clinical Pharmacology ( 12.3 )]. Caution and monitoring for chemotherapeutic related adverse reactions are advised in patients receiving chemotherapy agents metabolized primarily by CYP3A4.

Oral Contraceptives

There is no clinically significant effect of AKYNZEO on the efficacy of oral contraceptives containing levonorgestrel and ethinyl estradiol [see Clinical Pharmacology ( 12.3 )].

Warfarin

Although it was predicted that co-administration of intravenous AKYNZEO with warfarin would not substantially increase the systemic exposure to S-warfarin (CYP2C9 substrate), the active enantiomer, the effects of AKYNZEO for injection and AKYNZEO capsules on INR and prothrombin time have not been studied. Monitor INR and adjust the dosage of warfarin, as needed with concomitant use of AKYNZEO, to maintain the target INR range.

Netupitant is mainly metabolized by CYP3A4.

Palonosetron is mainly metabolized by CYP2D6 and to a lesser extent by CYP3A4 and CYP1A2. 

CYP3A4 Inducers

Avoid concomitant use of AKYNZEO in patients who are chronically using a strong CYP3A4 inducer such as rifampin. A strong CYP3A inducer can decrease the efficacy of AKYNZEO by substantially reducing plasma concentrations of the netupitant component [see Clinical Pharmacology ( 12.3 )].

CYP3A4 Inhibitors

Concomitant use of AKYNZEO with a strong CYP3A4 inhibitor (e.g., ketoconazole) can increase the systemic exposure to the netupitant component of AKYNZEO. However, no dosage adjustment is necessary for single dose administration of AKYNZEO [see Clinical Pharmacology ( 12.3 )].

Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT₃ receptor antagonists and other serotonergic drugs, including selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs). If symptoms occur, discontinue AKYNZEO and initiate supportive treatment [see Warnings and Precautions (5.2)].

Risk Summary

Limited available data with AKYNZEO use in pregnant women are insufficient to inform a drug- associated risk of adverse developmental outcomes. In animal reproduction studies with netupitant, no effects on embryo-fetal development were observed following daily oral administration in pregnant rats during the period of organogenesis at doses up to 3.7 times the human AUC (area under the plasma concentration-time curve) at the recommended single dose to be given with each cycle of chemotherapy. However, a dose-dependent increase in adverse effects on embryo-fetal development was observed following daily oral administration of netupitant in pregnant rabbits during the period of organogenesis with doses at least 0.2 times the human AUC at the recommended single dose to be given with each cycle of chemotherapy. Daily oral administration of netupitant in rats up to 3.7 times the human AUC at the recommended dose during organogenesis through lactation produced no adverse effects in the offspring (see Data).

In animal reproduction studies with fosnetupitant, delayed ossification of pubis occurred after intravenous administration in rats during the period of organogenesis at a dose 3 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy. In pregnant rabbits, an increase in resorptions was observed with daily intravenous administration of fosnetupitant during the period of organogenesis at doses up to 9 times the human AUC for fosnetupitant and 0.4 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy. Daily intravenous administration of fosnetupitant (3 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy) in rats during organogenesis through lactation produced lower bodyweight in offspring at birth through maturation, and delayed physical development (see Data).

In animal reproduction studies with palonosetron, no effects on embryo-fetal development were observed following oral administration during the period of organogenesis at doses up to 921 and 1841 times the recommended oral dose in rats and rabbits, respectively (see Data).
Based on animal data from netupitant studies, advise pregnant women of the potential risk to a fetus.

The estimated background risk of major birth defects and miscarriage for the indicated populations are unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. 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.

Data

Animal Data

Netupitant

Daily oral administration of up to 30 mg/kg netupitant in rats (3.7 times the human AUC at the recommended single dose to be given with each cycle of chemotherapy) during the period of organogenesis produced no effects on embryo-fetal development. However, an increased incidence of external and skeletal abnormalities in rabbit fetuses was observed following daily oral administration of netupitant in rabbits at 10 mg/kg/day and higher (0.2 times the human AUC at the recommended single dose to be given with each cycle of chemotherapy) during the period of organogenesis. These abnormalities included positional abnormalities in the limbs and paws, and fused sternebrae. Reduction in fetal rabbit weight occurred at 30 mg/kg/day. Maternal toxicity in rabbits (i.e., loss of bodyweight during the treatment period) was also observed at 30 mg/kg/day. Daily oral administration of up to 30 mg/kg netupitant (3.7 times the human AUC at the recommended dose) in rats during organogenesis through lactation produced no adverse effects in the offspring.

Fosnetupitant

Daily intravenous administration of 39 mg/kg/day fosnetupitant in rats (3 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy) during the period of organogenesis produced delayed ossification of pubis.  No effects on embryo-fetal development were observed with daily administration of up to 13 mg/kg fosnetupitant in rats (2 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy).  Due to the limited systemic exposure to fosnetupitant in pregnant rats, it is not possible to provide an AUC-based comparison of fosnetupitant exposure in rats and humans.  An increase in resorptions was observed with daily intravenous administration of fosnetupitant at 6 mg/kg/day and higher in rabbits (9 times the human AUC for fosnetupitant and 0.4 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy) during the period of organogenesis.  No effects were observed in rabbits at 3 mg/kg/day (5.4 times the human AUC for fosnetupitant and 0.4 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy).  Daily intravenous administration of 39 mg/kg fosnetupitant in rats (3 times the AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy) during organogenesis through lactation produced lower bodyweight in offspring at birth through maturation, and delayed physical development (pinna detachment, eye opening, and preputial separation).  These effects were associated with maternal toxicity (reduced weight gain and food consumption).  No effects occurred in offspring or dams at 13 mg/kg/day (2 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy).

Palonosetron

In animal reproduction studies with palonosetron, no effects on embryo-fetal development were observed in pregnant rats given oral doses up to 60 mg/kg/day (921 times the recommended oral dose based on body surface area) or pregnant rabbits given oral doses up to 60 mg/kg/day (1841 times the recommended oral dose based on body surface area) during the period of organogenesis.

Risk Summary

There are no data on the presence of netupitant (or fosnetupitant) or palonosetron in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for AKYNZEO and any potential adverse effect on the breastfed child from AKYNZEO or from the underlying maternal condition.

The safety and effectiveness of AKYNZEO in patients below the age of 18 years have not been established.

Of the 1169 adult cancer patients treated with AKYNZEO capsules in clinical studies, 18% were aged 65 and over, while 2% were aged 75 years and over. The nature and frequency of adverse reactions were similar in elderly and younger patients. Exploratory analyses of the impact of age on efficacy were performed in the two trials that compared AKYNZEO to palonosetron [see Clinical Studies ( 14 )]. In Study 1 in patients treated with cisplatin chemotherapy, among the patients less than age 65 years, 115 were treated with AKYNZEO and 116 were treated with palonosetron alone.  Among the patients 65 years or older, 20 were treated with AKYNZEO and 20 were treated with palonosetron alone. The difference in Complete Response (CR) rates between AKYNZEO and palonosetron alone was similar between the two age groups in both the acute and delayed phases. In Study 2 in patients treated with anthracyclines plus cyclophosphamide chemotherapy, among the patients less than age 65 years, 608 were treated with AKYNZEO and 602 were treated with palonosetron alone. Among the patients 65 years or older, 116 were treated with AKYNZEO and 123 were treated with palonosetron alone. The difference in CR rates between AKYNZEO and palonosetron alone (4% in <65 years and 2% in >65 years) was similar between the two age groups in the acute phase. In the delayed phase, the difference in CR rates between AKYNZEO and palonosetron alone (9% in <65 years and 1% in ≥ 65 years) was numerically higher in patients <65 years. This difference between age groups in the delayed phase of Study 2 may be explained, in part, by higher CR in the delayed phase associated with palonosetron alone in the older age group (81%) relative to the younger patients treated with palonosetron alone (67%).

Of the 239 adult cancer patients treated with AKYNZEO for injection in clinical studies, 36% were aged 65 and over, while 4% were aged 75 years and over. The nature and frequency of adverse reactions were similar in elderly and younger patients.

In general, use caution when dosing elderly patients as they have a greater frequency of decreased hepatic, renal or cardiac function and concomitant disease or other drug therapy.

No dosage adjustment for AKYNZEO is necessary for patients with mild to moderate hepatic impairment (Child-Pugh score 5 to 8). Limited data are available with AKYNZEO in patients with severe hepatic impairment (Child-Pugh score greater than 9). Avoid use of AKYNZEO in patients with severe hepatic impairment [see Overdosage (10), Clinical Pharmacology (12.3)].

No dosage adjustment for AKYNZEO is necessary in patients with mild to moderate renal impairment (creatinine clearance of 30 to 60 mL/min). The pharmacokinetics and safety of netupitant have not been studied in patients with severe renal impairment.  Severe renal impairment (creatinine clearance < 30 mL/min) did not substantially affect pharmacokinetics of palonosetron. The pharmacokinetics for netupitant and palonosetron were not studied in patients with end-stage renal disease requiring hemodialysis. Avoid use of AKYNZEO in patients with severe renal impairment or end-stage renal disease [see Clinical Pharmacology (12.3)].

Netupitant is a selective antagonist of human substance P/neurokinin 1 (NK-1) receptors.

Palonosetron is a 5-HT₃ receptor antagonist with a strong binding affinity for this receptor and little or no affinity for other receptors. Cancer chemotherapy may be associated with a high incidence of nausea and vomiting, particularly when certain agents, such as cisplatin, are used. 5-HT₃ receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema. Chemotherapeutic agents produce nausea and vomiting by stimulating the release of serotonin from the enterochromaffin cells of the small intestine. Serotonin then activates 5-HT₃ receptors located on vagal afferents to initiate the vomiting reflex. The development of acute emesis is known to depend on serotonin and its 5-HT₃ receptors have been demonstrated to selectively stimulate the emetic response.

Delayed emesis has been largely associated with the activation of tachykinin family neurokinin 1 (NK-1) receptors (broadly distributed in the central and peripheral nervous systems) by substance P. As shown in in vitro and in vivo studies, netupitant inhibits substance P mediated responses.

NK-1 Receptor Occupancy

The receptor occupancy of netupitant was measured in a human Positron Emission Tomography (PET) study. Netupitant was shown to cross the blood brain barrier with a NK-1 receptor occupancy of 92.5%, 86.5%, 85.0%, 78.0%, and 76.0% in striatum at 6, 24, 48, 72, and 96 hours, respectively, after oral administration of 300 mg netupitant.

Cardiac Electrophysiology

An AKYNZEO oral dose of 600 mg netupitant (2 times the recommended dose) and 1.5 mg palonosetron (3 times the recommended dose) did not prolong the QT interval to any clinically relevant extent. 

The recommended dose of AKYNZEO for injection (235 mg fosnetupitant and 0.25 mg palonosetron) did not prolong the QT interval to any clinically relevant extent. 

Netupitant and Palonosetron

Absorption

Upon single oral administration of AKYNZEO capsules to healthy subjects and patients, netupitant and palonosetron were measurable within 1 hour after administration and reached the maximum concentration (Cmax) in approximately 4 to 5 hours (Table 8). 

Following oral administration, the absolute bioavailability of palonosetron was approximately 97%.

When AKYNZEO capsules were administered under fed conditions, the systemic exposure to netupitant and palonosetron was similar to the exposure under fasting conditions.

In cancer patients who received a single dose of AKYNZEO capsules 1 hour prior to chemotherapy (docetaxel, etoposide, or cyclophosphamide), the C_max and the area under the concentration-time curve from time zero to infinity (AUC_inf ) of netupitant and its metabolites were similar to those in healthy subjects. The mean C_max and AUC_inf of palonosetron in cancer patients were similar to those in healthy subjects.

No changes in pharmacokinetics of netupitant and palonosetron were observed when 450 mg oral netupitant and 0.75 mg oral palonosetron were given alone or co-administered (1.5 times the recommended dose of AKYNZEO capsules).

Dose Proportionality

Netupitant

There was a greater than dose-proportional increase in the systemic exposure (108-fold AUC_inf increase for a 30-fold dose increase) when the oral netupitant dose was increased from 10 mg (approximately 3% the recommended dose in AKYNZEO capsules) to 300 mg of netupitant and a dose-proportional increase in the systemic exposure when the netupitant dose was increased from 300 mg to 450 mg of netupitant (1.5 times the recommended dose in AKYNZEO capsules).

Palonosetron

After single oral doses of palonosetron ranging from 0.25 to 6.8 mg (0.5 to 13.6 times the recommended dose in AKYNZEO capsules) using a buffered solution, the mean C_max and AUC_inf were dose proportional in healthy subjects.

Following single intravenous doses of AKYNZEO for injection in patients or fosnetupitant in healthy subjects, C_max of netupitant and palonosetron were achieved at the end of the 30-minute infusion (Table 9).

Distribution

After single oral administration of AKYNZEO capsules, netupitant and palonosetron were widely distributed throughout the body (Table 10).

After administration of single dose of AKYNZEO for injection in patients, the mean ± SD of volume of distribution (Vz) of netupitant and palonosetron were 2627 ± 990 L and 594 ± 239 L, respectively, consistent with previous estimates after single oral administration of AKYNZEO capsules in healthy subjects and cancer patients (Table 10). 

Elimination – Netupitant

After a single dose of AKYNZEO capsules, netupitant is eliminated from the body in a multi-exponential fashion and the mean ± SD of apparent elimination half-life was of 96 ± 59 hours in healthy subjects and 80 ± 29 hours in cancer patients. The mean ± SD of estimated systemic clearance (CL/F) was 26.3 ± 12.5 L/h in healthy subjects and 20.3 ± 9.2 L/h in patients.

In patients, following intravenous infusion of AKYNZEO for injection, the mean ± SD total body clearance (CL) and terminal half-life (t_1/2) of netupitant were 14.1 ± 5.3 L/h and 144 ± 73 hours, respectively.

Metabolism

Once absorbed, netupitant is extensively metabolized to form three major metabolites: desmethyl derivative, M1; N-oxide derivative, M2; and OH-methyl derivative, M3. Metabolism is mediated primarily by CYP3A4 and to a lesser extent by CYP2C9 and CYP2D6. Metabolites M1, M2 and M3 were shown to bind to the substance P/neurokinin 1 (NK-1) receptor.

The mean AUC_inf for metabolites M1, M2 and M3 was 29%, 14% and 33% of netupitant, respectively. The median t_max for metabolite M2 was 5 hours and was about 17 to 32 hours for metabolites M1 and M3, respectively. 

Excretion

After a single oral administration of [¹⁴C]­netupitant, approximately half the administered radioactivity was recovered from urine and feces within 120 hours of dosing. The total of 3.95% and 70.7% of the radioactive dose was recovered in the urine and feces collected over 336 hours, respectively, and the mean fraction of an oral dose of netupitant excreted unchanged in urine is less than 1% suggesting renal clearance is not a significant elimination route for the netupitant-related entities. About 86.5% and 4.7% of administered radioactivity was estimated to be excreted via the feces and urine within 30 days post-dose.

Elimination - Palonosetron

Following oral administration of AKYNZEO capsules in healthy subjects and cancer patients, the mean ( ± SD) of half-life of palonosetron was 44 ± 15 hours and 50 ± 16 hours, respectively, whereas the mean ± SD of total body clearance (CL/F) was 9.6 ± 2.7 L/h and 10.0 ± 3.4 L/h, respectively.

After a single intravenous palonosetron dose of 10 mcg/kg (approximately 3 times the recommended dose in AKYNZEO for injection), the mean ± SD of total body clearance (CL) of palonosetron in healthy subjects was 12.1 ± 3.7 L/h, and renal clearance (CL_R) was 5.1 ± 2.1 L/h.

In patients, following intravenous infusion of AKYNZEO for injection, the mean ± SD total body clearance (CL) and terminal half-life (t_1/2) of palonosetron were 7.6 ± 2.6 L/h and 58 ± 27 h, respectively.

Metabolism

Palonosetron is eliminated by multiple routes with approximately 50% metabolized to form two primary metabolites: N-oxide-palonosetron and 6-S­hydroxy-palonosetron. These metabolites each have less than 1% of the 5-HT₃ receptor antagonist activity of palonosetron. In vitro metabolism studies have suggested that CYP2D6 and to a lesser extent CYP3A4 and CYP1A2 are involved in the metabolism of palonosetron.  However, clinical pharmacokinetic parameters such as C_max, AUC_inf, CL, CL_R, V_z and t_1/2 are not significantly different between poor and extensive metabolizers of CYP2D6 substrates.

Excretion

Following administration of a single oral 0.75 mg dose of [¹⁴C]­palonosetron (1.5 times the recommended dose in AZKYNZEO capsules) to six healthy subjects, 85% to 93% of the total radioactivity was excreted in urine, and 5% to 8% was eliminated in feces. The amount of unchanged palonosetron excreted in the urine represented approximately 40% of the administered dose.

Fosnetupitant

Absorption

Following single intravenous doses of AKYNZEO for injection in patients (235 mg fosnetupitant and 0.25 mg palonosetron infused in 30 minutes) or fosnetupitant in healthy subjects (235 mg fosnetupitant infused in 30 minutes), maximum concentrations of fosnetupitant were achieved at the end of the 30-minute infusion (Table 11).

In cross-study comparisons, the mean C_max and AUC_inf of fosnetupitant were lower in patients than in healthy subjects.  Similarly, AUC_0-120 and C_max of netupitant in patients were 26% and 30% lower than in healthy subjects, respectively (Table 9).  The differences in systemic exposures to netupitant are clinically insignificant.

In healthy subjects, there was a dose-proportional increase in the systemic exposure when the dose of fosnetupitant was increased from 17.6 mg (7.5% of recommended dose in AKYNZEO for injection) to 353 mg (150% of recommended dose in AKYNZEO for injection).

Distribution

The mean ± SD volume of distribution (V_z) of fosnetupitant in healthy subjects and in patients was 124 ± 76 L and 296 ±535 L, respectively. The human plasma protein binding of fosnetupitant was 92% at 1 micromolar and 95% at 10 micromolar.

Elimination

After intravenous administration of AKYNZEO for injection, fosnetupitant plasma concentrations declined in a biexponential manner. Thirty minutes after the end of the infusion, the mean plasma concentration of fosnetupitant was less than 1% of C_max. 

The mean ± SD of terminal elimination half-life and systemic plasma clearance (CL) of fosnetupitant were respectively 0.75 ± 0.40 hours and 249 ± 270 L/h in cancer patients after a single IV dose of AKYNZEO.  They were 0.96 ± 0.55 hours (mean ± SD) and 90 ± 13 L/h in healthy subjects after a single intravenous dose of fosnetupitant.

Metabolism

Fosnetupitant is converted in vivo to netupitant by metabolic hydrolysis. In patients receiving AKYNZEO intravenously, netupitant exposure was 17-fold fosnetupitant exposure, as determined by their AUC_inf ratio. Netupitant metabolites M1, M2 and M3 were generated from the released netupitant. In patients, metabolite M1, M2 and M3 exposures were 32%, 21% and 28% of netupitant exposure. The median t_max for M1, M2, and M3 were 12, 2 and 12 hours, respectively.

Specific Populations

Geriatric Patients

In cancer patients receiving AKYNZEO capsules, population pharmacokinetic analysis indicated that age (within the range of 29 to 75 years) did not influence the pharmacokinetics of netupitant or palonosetron.  In healthy elderly subjects (greater than 65 years of age) the mean AUC_inf and C_max was 25% and 36% higher, respectively, for netupitant, and 37% and 10% higher, respectively, for palonosetron compared to those in healthy younger adults (22 to 45 years of age).  The increase in the systemic exposure to netupitant in the elderly subjects is not considered to be clinically significant. 

Male and Female Patients

In a pooled analysis of data following AKYNZEO capsules, the C_max for netupitant was 35% higher in females than in males while the AUC_inf was similar between males and females.  In female subjects, the mean AUC_inf for palonosetron was 35% higher and the mean C_max was 26% higher than in male subjects.  Sex did not affect the pharmacokinetics of fosnetupitant, netupitant, netupitant metabolites and palonosetron after a single intravenous dose of AKYNZEO in patients.  In healthy subjects, no effect of sex was observed on the pharmacokinetics of fosnetupitant, netupitant and its metabolites after a single intravenous dose of fosnetupitant alone.  The mean ± SD of netupitant AUC_inf and C_max in patients were 15672 ±  5496 ng×h/mL and 567 ± 174 ng/mL, respectively in males and 15518 ± 4814 ng×h/mL and 609 ± 161 ng/mL, respectively in females.

Patients with Renal Impairment

Population pharmacokinetic analysis showed that mild and moderate renal impairment (creatinine clearance 30 to 60 mL/min) did not significantly affect the pharmacokinetics of netupitant in cancer patients. Netupitant has not been studied in patients with severe renal impairment (creatinine clearance less than 30 mL/min).

Mild to moderate renal impairment does not significantly affect palonosetron pharmacokinetic parameters. In a study with intravenous palonosetron, total systemic exposure to palonosetron increased by approximately 28% in patients with severe renal impairment relative to healthy subjects.

The pharmacokinetics of palonosetron and netupitant have not been studied in subjects with end-stage renal disease (creatinine clearance < 15 mL/min not on dialysis) [see Use in Specific Populations (8.7)].

Patients with Hepatic Impairment

The effects of hepatic impairment on the pharmacokinetics of netupitant and palonosetron were studied following administration of a single oral dose of AKYNZEO to patients with mild (Child-Pugh score 5 to 6), moderate (Child-Pugh score 7 to 9), or severe (Child-Pugh score >9) hepatic impairment.

In patients with mild or moderate hepatic impairment, the mean AUC_inf of netupitant was 67% and 86% higher, respectively, than in healthy subjects and the mean C_max for netupitant was about 40% and 41% higher, respectively, than in healthy subjects.

In patients with mild or moderate hepatic impairment, the mean AUC_inf of palonosetron was 33% and 62% higher, respectively, than in healthy subjects and the mean C_max for palonosetron was about 14% higher and unchanged, respectively, than in healthy subjects.

The pharmacokinetics of netupitant and palonosetron were available from only two patients with severe hepatic impairment. As such the data are too limited to draw a conclusion [see Use in Specific Populations (8.6)]. 

Drug Interaction Studies

Effect of Netupitant/Fosnetupitant and/or Palonosetron on Other Drugs

CYP3A4

In vitro studies have shown that netupitant and its metabolite M1 are inhibitors of CYP3A4. An in vivo study has confirmed that netupitant is a moderate inhibitor of CYP3A4.

Dexamethasone

In healthy subjects, the oral administration of a single AKYNZEO capsule with the CYP3A4 substrate dexamethasone (12 mg on day 1 followed by once-a-day administrations of 8 mg on days 2, 3, 4, 6, 8 and 10), increased the plasma concentrations of dexamethasone for 6 days (Table 12).

In healthy subjects, co-administration of a single intravenous fosnetupitant dose (235 mg) with a 20 mg oral dexamethasone on day 1 followed by twice-a-day administrations of 8 mg dexamethasone on days 2, 3, and 4, increased dexamethasone exposure 2.4-fold on day 4 (Table 13).

Considering the limited fosnetupitant exposure in human plasma and its conversion to netupitant within 30 minutes after completion of infusion, the effects are ascribed to netupitant [see Drug Interactions (7.1)]. 

Midazolam

When co-administered with netupitant 300 mg the mean C_max and AUC_inf of midazolam after single dose oral administration of 7.5 mg midazolam was 36% and 126% higher, respectively [see Drug Interactions (7.1)].

Chemotherapeutic Agents (docetaxel, etoposide, cyclophosphamide)

Systemic exposure to intravenously administered chemotherapeutic agents that are metabolized by CYP3A4 was higher when AKYNZEO capsules was co-administered in cancer patients than when palonosetron alone was co-administered (see Table 14).

The mean AUC_inf of palonosetron was about 65% higher when AKYNZEO capsules was co-administered with docetaxel than with etoposide or cyclophosphamide, while the mean AUC_inf of netupitant was similar among groups that received docetaxel, etoposide, or cyclophosphamide [see Drug Interactions (7.1)].

Erythromycin

When 500 mg erythromycin was co-administered with netupitant 300 mg, the systemic exposure of erythromycin was highly variable and the mean Cmax and AUCinf of erythromycin were increased by 92% and 56%, respectively. The change in exposure is not clinically significant.

Oral Contraceptives

A single dose of AKYNZEO capsules, when given with a single oral dose of 60 mcg ethinyl estradiol and 300 mcg levonorgestrel, showed no effect on C_max and increased the AUC_0-t of levonorgestrel by 46%. The C_max and AUC_0-t of ethinyl estradiol increased by 5% and 16% respectively.  The change in exposure is not clinically significant [see Drug Interactions (7.1)].

Other CYP P450 enzymes

Based on the in vitro studies, netupitant, and its metabolites are unlikely to have in vivo drug-drug interaction via inhibition of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, and CYP2D6 at the clinical dose of oral AKYNZEO. 

Netupitant and its metabolites, M1, M2 and M3, are not inducers of CYP1A2, CYP2B6, CYP2C9, CYP2C19 and CYP3A4.

In in vitro studies, palonosetron did not inhibit CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1 and CYP3A4/5 or induce CYP1A2, CYP2D6 or CYP3A4/5. CYP2C19 was not investigated.

Transporters P-gp and BCRP

Based on in vitro studies, netupitant is an inhibitor of P-glycoprotein (P-gp) and breast cancer resistant protein (BCRP) transporters. In vitro studies indicated that fosnetupitant is an inhibitor of P-gp.  However, an in vivo  interaction between AKYNZEO for injection and P-gp substrates is considered unlikely.

In vitro, palonosetron was an inhibitor of MATE1, MATE2-K, OCT1, OCT2 and OAT3 transporters. An in vivo interaction between AKYNZEO capsules or injection and transporter substrates is considered unlikely.

Digoxin P-gp Substrate

Co-administration of oral netupitant 450 mg (1.5 times the recommended dose in AKYNZEO capsules) did not significantly affect the systemic exposure (4% increase of AUC_0-24 at steady state) and urinary excretion (2% increase) of oral digoxin, a substrate of P-gp, at steady-state. Concurrent administration of AKYNZEO capsules or AKYNZEO for injection with digoxin is not expected to affect the systemic exposure to digoxin.

Other Transporters

In vitro studies indicate that netupitant and its three major metabolites are unlikely to have in vivo drug-drug interactions with human efflux transporters BSEP, MRP2, and human uptake transporters OATP1B1, OATP1B3, OAT1, OAT3, OCT1, and OCT2 at the clinical dose of 300 mg.

In vitro studies indicated that fosnetupitant is an inhibitor of OATP1B1 and OATP1B3 transporters. However, an in vivo interaction between AKYNZEO for injection and OATP1B1, OATP1B3, and P-gp substrates is considered unlikely.

In vitro studies indicated that fosnetupitant is not an inhibitor of MATE2-K transporter.

Effects of Other Drugs on Netupitant/Fosnetupitant and/or Palonosetron

Based on in vitro studies, fosnetupitant is not a substrate of BCRP, BSEP, MDR1 and MATE1, MATE2-K, OAT1, OAT3, OATP2B1, OCT1 and OCT2.

Netupitant is not a substrate for P-gp. However, metabolite M2 is a substrate for P-gp.

Netupitant and palonosetron are CYP3A4 substrates. Co-administration of strong CYP3A4 inhibitors, such as ketoconazole, or strong CYP3A4 inducers, such as rifampin, with a single oral administration of AKYNZEO capsules affects with clinical significance the exposure to netupitant but not to palonosetron (Table 15).

Netupitant

Long-term studies in animals to evaluate carcinogenic potential have not been performed with netupitant. Netupitant was not genotoxic in the Ames test, the mouse lymphoma cell mutation test, or the in vivo rat micronucleus test.

Daily oral administration of netupitant in rats at doses up to 30 mg/kg (1.9 times the human AUC in male rats and 3.7 times the human AUC in female rats at the recommended dose) had no effects on fertility or reproductive performance.

Fosnetupitant

Long-term studies in animals to evaluate carcinogenic potential have not been performed with fosnetupitant.

Fosnetupitant was not genotoxic in the Ames test and in vivo rat micronucleus test. In human lymphocytes, fosnetupitant did not induce structural chromosomal aberrations.

Daily intravenous administration of fosnetupitant in rats at doses up to 39 mg/kg (1.3 times the human AUC for fosnetupitant and 4.3 times the human AUC for netupitant at the recommended single dose to be given with each cycle of chemotherapy) had no effects on fertility or reproductive performance.

Palonosetron

In a 104-week carcinogenicity study in CD-1 mice, animals were treated with oral doses of palonosetron at 10, 30, and 60 mg/kg/day. Treatment with palonosetron was not tumorigenic. The highest tested dose produced a systemic exposure to palonosetron (plasma AUC) of about 90 to 173 times the human exposure (AUC=49.7 ng•h/mL) at the recommended oral dose of 0.5 mg. In a 104-week carcinogenicity study in Sprague-Dawley rats, male and female rats were treated with oral doses of 15, 30, and 60 mg/kg/day and 15, 45, and 90 mg/kg/day, respectively. The highest doses produced a systemic exposure to palonosetron (plasma AUC) of 82 and 185 times the human exposure at the recommended dose. Treatment with palonosetron produced increased incidences of adrenal benign pheochromocytoma and combined benign and malignant pheochromocytoma, increased incidences of pancreatic Islet cell adenoma and combined adenoma and carcinoma and pituitary adenoma in male rats. In female rats, it produced hepatocellular adenoma and carcinoma and increased the incidences of thyroid C-cell adenoma and combined adenoma and carcinoma.

Palonosetron was not genotoxic in the Ames test, the Chinese hamster ovarian cell (CHO/HGPRT) forward mutation test, the ex vivo hepatocyte unscheduled DNA synthesis (UDS) test, or the mouse micronucleus test. It was, however, positive for clastogenic effects in the Chinese hamster ovarian (CHO) cell chromosomal aberration test. Palonosetron at oral doses up to 60 mg/kg/day (about 921 times the recommended oral dose based on body surface area) was found to have no effect on fertility and reproductive performance of male and female rats.