Fosaprepitant Dimeglumine Injection, Powder, Lyophilized, For Solution
FDA Label NDC 0143-9384

Fosaprepitant  for Injection, in combination with other antiemetic agents, is indicated in adults for the prevention of:

• acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin.
• delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (MEC).

Limitations of Use

• Fosaprepitant for Injection has not been studied for the treatment of established nausea and vomiting.

The recommended dosage of fosaprepitant for injection, dexamethasone, and a 5-HT₃ antagonist for the prevention of nausea and vomiting associated with administration of HEC or MEC in adults is shown in Table 1 or Table 2, respectively. Administer fosaprepitant for injection as an intravenous infusion on Day 1 over 20 to 30 minutes, completing the infusion approximately 30 minutes prior to chemotherapy.

Caution: Do not mix or reconstitute fosaprepitant for injection with solutions for which physical and chemical compatibility have not been established. Fosaprepitant for Injection is incompatible with any solutions containing divalent cations (e.g., Ca²⁺, Mg²⁺), including Lactated Ringer's Solution and Hartmann's Solution.

Fosaprepitant for Injection: 150 mg fosaprepitant, white to off-white lyophilized powder in single-dose glass vial for reconstitution

Fosaprepitant for Injection is contraindicated in patients:

• who are hypersensitive to any component of the product. Hypersensitivity reactions including anaphylactic reactions, flushing, erythema, and dyspnea have been reported [see Warnings and Precautions (5.2), Adverse Reactions (6.2)].
• taking pimozide. Inhibition of CYP3A4 by aprepitant, the active moiety, could result in elevated plasma concentrations of this drug, which is a CYP3A4 substrate, potentially causing serious or life-threatening reactions, such as QT prolongation, a known adverse reaction of pimozide [see Warnings and Precautions (5.1)].

Fosaprepitant, a prodrug of aprepitant, is a weak inhibitor of CYP3A4, and aprepitant is a substrate, inhibitor, and inducer of CYP3A4.

• Use of fosaprepitant for injection with other drugs that are CYP3A4 substrates, may result in increased plasma concentration of the concomitant drug.
  • Use of pimozide with fosaprepitant for injection is contraindicated due to the risk of significantly increased plasma concentrations of pimozide, potentially resulting in prolongation of the QT interval, a known adverse reaction of pimozide [see Contraindications (4)].
  • Use of fosaprepitant for injection with strong or moderate CYP3A4 inhibitors (e.g., ketoconazole, diltiazem) may increase plasma concentrations of aprepitant and result in an increased risk of adverse reactions related to fosaprepitant for injection.
  • Use of fosaprepitant for injection with strong CYP3A4 inducers (e.g., rifampin) may result in a reduction in aprepitant plasma concentrations and decreased efficacy of fosaprepitant for injection.

  See Table 7 and Table 8 for a listing of potentially significant drug interactions [see Drug Interactions (7.1, 7.2)].

Serious hypersensitivity reactions, including anaphylaxis and anaphylactic shock, during or soon after infusion of fosaprepitant for injection have occurred. Symptoms including flushing, erythema, dyspnea, hypotension and syncope have been reported [see Adverse Reactions (6.2)].

Monitor patients during and after infusion. If hypersensitivity reactions occur, discontinue the infusion and administer appropriate medical therapy. Do not reinitiate fosaprepitant for injection in patients who experience these symptoms with previous use [see Contraindications (4)].

Infusion site reactions (ISRs) have been reported with the use of fosaprepitant for injection [see Adverse Reactions (6.1)]. The majority of severe ISRs, including thrombophlebitis and vasculitis, were reported with concomitant vesicant (anthracycline-based) chemotherapy administration, particularly when associated with extravasation. Necrosis was also reported in some patients with concomitant vesicant chemotherapy. Most ISRs occurred with the first, second or third exposure to single doses of fosaprepitant for injection and in some cases, reactions persisted for two weeks or longer. Treatment of severe ISRs consisted of medical, and in some cases surgical, intervention.

Avoid infusion of fosaprepitant for injection into small veins or through a butterfly catheter. If a severe ISR develops during infusion, discontinue the infusion and administer appropriate medical treatment.

Coadministration of fosaprepitant for injection with warfarin, a CYP2C9 substrate, may result in a clinically significant decrease in the International Normalized Ratio (INR) of prothrombin time [see Clinical Pharmacology (12.3)]. Monitor the INR in patients on chronic warfarin therapy in the 2-week period, particularly at 7 to 10 days, following initiation of fosaprepitant for injection with each chemotherapy cycle [see Drug Interactions (7.1)].

Upon coadministration with fosaprepitant for injection, the efficacy of hormonal contraceptives may be reduced during administration of and for 28 days following the last dose of fosaprepitant for injection [see Clinical Pharmacology (12.3)]. Advise patients to use effective alternative or back-up methods of contraception during treatment with fosaprepitant for injection and for 1 month following administration of fosaprepitant for injection [see Drug Interactions (7.1), Use in Specific Populations (8.3)].

The following clinically significant adverse reactions are described elsewhere in the labeling:

• Hypersensitivity Reactions [see Warnings and Precautions (5.2)]
• Infusion Site Reactions [see Warnings and Precautions (5.3)]

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 clinical practice.

The overall safety of fosaprepitant for injection was evaluated in approximately 1600 adult patients.

The following adverse reactions have been identified during post-approval use of fosaprepitant. 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.

Skin and subcutaneous tissue disorders: pruritus, rash, urticaria, Stevens-Johnson syndrome/toxic epidermal necrolysis [see Warnings and Precautions (5.2)].

Immune system disorders: hypersensitivity reactions including anaphylaxis and anaphylactic shock [see Contraindications (4), Warnings and Precautions (5.2)].

Nervous system disorders: ifosfamide-induced neurotoxicity reported after fosaprepitant for injection and ifosfamide coadministration.

When administered intravenously, fosaprepitant, a prodrug of aprepitant, is converted to aprepitant within 30 minutes. Therefore, drug interactions following administration of fosaprepitant for injection are likely to occur with drugs that interact with oral aprepitant.

Fosaprepitant, given as a single 150-mg dose, is a weak inhibitor of CYP3A4, and the weak inhibition of CYP3A4 continues for 2 days after single dose administration. Single dose fosaprepitant does not induce CYP3A4. Aprepitant is a substrate, an inhibitor, and an inducer of CYP3A4. Aprepitant is also an inducer of CYP2C9 [see Clinical Pharmacology (12.3)].

Some substrates of CYP3A4 are contraindicated with fosaprepitant for injection [see Contraindications (4)]. Dosage adjustment of some CYP3A4 and CYP2C9 substrates may be warranted, as shown in Table 7.

Aprepitant is a CYP3A4 substrate [see Clinical Pharmacology (12.3)]. Co-administration of fosaprepitant for injection with drugs that are inhibitors or inducers of CYP3A4 may result in increased or decreased plasma concentrations of aprepitant, respectively, as shown in Table 8.

The safety and effectiveness of fosaprepitant for injection for the prevention of nausea and vomiting associated with HEC or MEC have not been established in patients less than 6 months of age.

Juvenile Animal Toxicity Data
In juvenile dogs treated with fosaprepitant, changes in reproductive organs were observed. In juvenile rats treated with aprepitant, slight changes in sexual maturation were observed without an effect on reproduction. No effects on neurobehavior, sensory and motor function, or learning and memory were observed in rats.

In a toxicity study in juvenile dogs treated with fosaprepitant from postnatal day 14 (equivalent to a newborn human) to day 42 (approximately equivalent to a 2 year old human), decreased testicular weight and Leydig cell size were seen in the males at 6 mg/kg/day and increased uterine weight, hypertrophy of the uterus and cervix, and edema of vaginal tissues were seen in females from 4 mg/kg/day. A study was also conducted in young rats to evaluate the effects of aprepitant on growth and on neurobehavioral and sexual development. Rats were treated at oral doses up to the maximum feasible dose of 1000 mg/kg twice daily from the early postnatal period (Postnatal Day 10 (equivalent to a newborn human) through Postnatal Day 58 (approximately equivalent to a 15 year old human)). Slight changes in the onset of sexual maturation were observed in female and male rats; however, there were no effects on mating, fertility, embryonic-fetal survival, or histomorphology of the reproductive organs. There were no effects in neurobehavioral tests of sensory function, motor function, and learning and memory.

Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.

Of the 1649 adult cancer patients treated with intravenous fosaprepitant for injection in HEC and MEC clinical studies, 27% were aged 65 and over, while 5% were aged 75 and over. Other reported clinical experience with fosaprepitant for injection has not identified differences in responses between 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 [see Clinical Pharmacology (12.3)].

The pharmacokinetics of aprepitant in patients with mild and moderate hepatic impairment were similar to those of healthy subjects with normal hepatic function. No dosage adjustment is necessary for patients with mild to moderate hepatic impairment (Child-Pugh score 5 to 9). There are no clinical or pharmacokinetic data in patients with severe hepatic impairment (Child-Pugh score greater than 9). Therefore, additional monitoring for adverse reactions in these patients may be warranted when fosaprepitant for injection is administered [see Clinical Pharmacology (12.3)].

There is no specific information on the treatment of overdosage with fosaprepitant or aprepitant.

In the event of overdose, fosaprepitant for injection should be discontinued and general supportive treatment and monitoring should be provided. Because of the antiemetic activity of fosaprepitant for injection, drug-induced emesis may not be effective in cases of fosaprepitant for injection overdosage.

Aprepitant is not removed by hemodialysis.

Fosaprepitant for Injection is a sterile, lyophilized formulation containing fosaprepitant dimeglumine, a prodrug of aprepitant, a substance P/neurokinin-1 (NK₁) receptor antagonist, an antiemetic agent, chemically described as 1-Deoxy-1-(methylamino)-D-glucitol[3-[[(2R,3S)-2-[(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethoxy]-3-(4-fluorophenyl)-4-morpholinyl]methyl]-2,5-dihydro-5-oxo-1H-1,2,4-triazol-1-yl]phosphonate (2:1) (salt).

Its empirical formula is C₂₃H₂₂F₇N₄O₆P ∙ 2(C₇H₁₇NO₅) and its structural formula is:

Chemical Structure (Fosaprepitant For Injection 1)

Fosaprepitant dimeglumine is a white or off-white amorphous powder with a molecular weight of 1004.83. It is freely soluble in water.

Each vial of fosaprepitant for injection for administration as an intravenous infusion contains 150 mg of fosaprepitant (equivalent to 245.3 mg of fosaprepitant dimeglumine) and the following inactive ingredients: edetate disodium (5.4 mg), polysorbate 80 (75 mg), lactose anhydrous (375 mg), sodium hydroxide and/or hydrochloric acid (for pH adjustment).

Fosaprepitant is a prodrug of aprepitant and accordingly, its antiemetic effects are attributable to aprepitant.

Aprepitant is a selective high-affinity antagonist of human substance P/neurokinin 1 (NK₁) receptors. Aprepitant has little or no affinity for serotonin (5-HT₃), dopamine, and corticosteroid receptors, the targets of existing therapies for chemotherapy-induced nausea and vomiting (CINV). Aprepitant has been shown in animal models to inhibit emesis induced by cytotoxic chemotherapeutic agents, such as cisplatin, via central actions. Animal and human Positron Emission Tomography (PET) studies with aprepitant have shown that it crosses the blood brain barrier and occupies brain NK₁ receptors. Animal and human studies have shown that aprepitant augments the antiemetic activity of the 5-HT₃-receptor antagonist ondansetron and the corticosteroid dexamethasone and inhibits both the acute and delayed phases of cisplatin-induced emesis.

In a randomized, parallel, double-blind, active-controlled study, fosaprepitant for injection 150 mg as a single intravenous infusion (N=1147) was compared to a 3-day oral aprepitant regimen (N=1175) in patients receiving a HEC regimen that included cisplatin (≥70 mg/m²). All patients in both groups received dexamethasone and ondansetron (see Table 11). Patient demographics were similar between the two treatment groups. Of the total 2322 patients, 63% were men, 56% White, 26% Asian, 3% American Indian/Alaska Native, 2% Black, 13% Multi-Racial, and 33% Hispanic/Latino ethnicity. Patient ages ranged from 19 to 86 years of age, with a mean age of 56 years. Other concomitant chemotherapy agents commonly administered were fluorouracil (17%), gemcitabine (16%), paclitaxel (15%), and etoposide (12%).

The efficacy of fosaprepitant for injection was evaluated based on the primary and secondary endpoints listed in Table 12 and was shown to be non-inferior to that of the 3-day oral aprepitant regimen with regard to complete response in each of the evaluated phases. The pre-specified non-inferiority margin for complete response in the overall phase was 7%. The pre-specified non-inferiority margin for complete response in the delayed phase was 7.3%. The pre-specified non-inferiority margin for no vomiting in the overall phase was 8.2%.

In a randomized, parallel, double-blind, active comparator-controlled study, fosaprepitant for injection 150 mg as a single intravenous infusion (N=502) in combination with ondansetron and dexamethasone (fosaprepitant for injection regimen) was compared with ondansetron and dexamethasone alone (standard therapy) (N=498) (see Table 13) in patients receiving a MEC regimen. Patient demographics were similar between the two treatment groups. Of the total 1,000 patients included in the efficacy analysis, 41% were men, 84% White, 4% Asian, 1% American Indian/Alaska Native, 2% Black, 10% Multi-Racial, and 19% Hispanic/Latino ethnicity. Patient ages ranged from 23 to 88 years of age, with a mean age of 60 years. The most commonly administered MEC chemotherapeutic agents were carboplatin (51%), oxaliplatin (24%), and cyclophosphamide (12%).

The primary endpoint was complete response (defined as no vomiting and no rescue therapy) in the delayed phase (25 to 120 hours) of chemotherapy-induced nausea and vomiting. The results by treatment group are shown in Table 14.

Single-dose glass vial containing 150 mg of fosaprepitant as a white to off-white lyophilized powder for reconstitution. Supplied as follows:

Advise the patient to read the FDA-approved patient labeling (Patient Information).

NDC 0143-9384-01     Rx only

Fosaprepitant
for Injection

150 mg per vial

Single Dose Vial
Discard unused portion

Label (Fosaprepitant For Injection 2)

NDC 0143-9384-01         Rx only

Fosaprepitant
for Injection

150 mg per vial

Reconstitute with 5 mL 0.9%
Sodium Chloride for Injection

STERILE LYOPHILIZED POWDER
FOR INTRAVENOUS USE ONLY AFTER
RECONSTITUTION AND DILUTION

DO NOT USE WITH SOLUTIONS
CONTAINING DIVALENT CATIONS
(e.g., Ca²⁺, Mg²⁺) INCLUDING
LACTATED RINGER'S SOLUTION
AND HARTMANN'S SOLUTION.

Single Dose Vial
Discard unused portion

Carton (Fosaprepitant For Injection 3)