2.1 Recommended Dosage

The recommended dosage is 16 mg/m2 intravenously over 15 to 20 minutes at 2-week intervals for 4 doses, then at 4-week intervals until unacceptable toxicity.

Administer prophylactic antiemetics [see Warnings and Precautions (5.2)].

2.2 Dosage Modifications for Adverse Reactions

See Table 1 for dosage modifications for adverse reactions related to bone marrow suppression [see Warnings and Precautions (5.1)].

Table 1. Dosage Modifications for Adverse Reaction: Bone Marrow Suppression

2.3 Dosage Modifications for Renal Impairment

Consider a dosage reduction of up to 50% in patients with renal insufficiency (BUN ≥30 mg/dL) [see Use in Specific Populations (8.6)].

2.4 Preparation and Administration

Preparation

• IVRA is a hazardous drug. Follow applicable special handling and disposal procedures1.
• Parenteral drug products should be visually inspected for particulate matter and discoloration prior to administration whenever solution and container permit. If either occurs, do not use this product.
• IVRA is light sensitive. After first use, store the partially used vial refrigerated at 2°C to 8°C [36°F to 46°F] in the original carton for use within 28 days and then discard the remaining contents. Retain vial in original carton until contents are used.
• Do not mix IVRA with other melphalan hydrochloride drug products.

Dilution

• Calculate the required volume of IVRA needed for a patient’s dose and withdraw that volume from the vial(s).
• Add the required volume of IVRA to the appropriate volume of 0.9% Sodium Chloride Injection to obtain a solution with a concentration not greater than 0.45 mg/mL. Immediately mix the contents of infusion vigorously by manual rotation. The diluted product is stable for 1 hour at room temperature.

Administration

• Infuse over 15 to 20 minutes via an injection port or central venous catheter. Complete administration within 60 minutes of dilution.
• IVRA may cause local tissue damage should extravasation occur. Administer IVRA only by injecting slowly into a fast-running intravenous infusion via an injection port or, central venous access line.

5.1 Bone Marrow Suppression

IVRA causes bone marrow suppression in most patients.

Obtain complete blood counts with differential at the start of therapy and prior to each subsequent dose of IVRA. Withhold treatment for grade 3 thrombocytopenia and/ or leukopenia until blood counts have returned to grade 2 [see Dosage and Administration (2.2)]. Consider dose adjustment on the basis of blood counts at the nadir and day of treatment.

5.2 Gastrointestinal Toxicity

Gastrointestinal disturbances such as nausea and vomiting, diarrhea, and oral ulceration can occur with melphalan treatment.

Severe mucositis, stomatitis, colitis, diarrhea, and hemorrhage of the gastrointestinal tract occur at high doses (greater than 100 mg/m2 6 times the recommended approved dose).

Use prophylactic antiemetics [see Dosage and Administration (2.1)]. Provide supportive care for nausea, vomiting, diarrhea, and mucositis.

5.3 Hepatotoxicity

Hepatic disorders ranging from abnormal liver function tests to clinical manifestations such as hepatitis and jaundice have been reported during treatment with melphalan. Hepatic veno-occlusive disease has been reported. Monitor liver enzymes as clinically indicated.

5.4 Hypersensitivity

Acute hypersensitivity reactions including anaphylaxis were reported in 2.4% of 425 patients receiving melphalan injection for myeloma. These reactions were characterized by urticaria, pruritus, edema, skin rashes, and in some patients, tachycardia, bronchospasm, dyspnea, and hypotension. These patients appeared to respond to antihistamine and corticosteroid therapy. If a hypersensitivity reaction occurs, intravenous or oral melphalan should not be readministered since hypersensitivity reactions have also been reported with oral melphalan. Cardiac arrest has also been reported in association with such reports.

Discontinue treatment with IVRA for serious hypersensitivity reactions.

5.5 Secondary Malignancies

Melphalan has been shown to cause chromatid or chromosome damage in humans. Secondary malignancies, including acute nonlymphocytic leukemia, myeloproliferative syndrome, and carcinoma, have been reported in patients with cancer treated with alkylating agents (including melphalan). Some patients also received other chemotherapeutic agents or radiation therapy. The potential benefits from melphalan therapy must be weighed on an individual basis against the possible risk of the induction of a second malignancy.

5.6 Embryo-Fetal Toxicity

Based on its mechanism of action, IVRA can cause fetal harm when administered to a pregnant woman. Melphalan is genotoxic, targets actively dividing cells, and was embryolethal and teratogenic in rats. While adequate animal studies have not been conducted with intravenous melphalan, oral (6 to 18 mg/m2/day for 10 days) and IP (18 mg/m2) administration in rats was embryolethal and teratogenic. Malformations resulting from melphalan included alterations of the brain (underdevelopment, deformation, meningocele, and encephalocele) and eye (anophthalmia and microphthalmos), reduction of the mandible and tail, as well as hepatocele (exomphaly).

If this drug is used during pregnancy or if the patient becomes pregnant while taking this drug, advise a pregnant woman of the of potential risk to the fetus. Advise females of reproductive potential to use effective contraception during treatment with IVRA and for 6 months after the last dose. Advise males with female partners of reproductive potential to use effective contraception during treatment with IVRA and for 3 months after the last dose [see Use in Specific Populations (8.1, 8.3)].

5.7 Infertility

Melphalan causes suppression of ovarian function in premenopausal women, resulting in amenorrhea in a significant number of patients. Reversible and irreversible testicular suppression have also been reported [see Use in Specific Populations (8.3)].

6.1 Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of melphalan may not reflect the rates observed in practice.

The most common adverse reactions observed in at least 50% of patients with multiple myeloma treated with melphalan were neutrophil count decreased, white blood cell count decreased, lymphocyte count decreased, platelet count decreased, diarrhea, nausea, fatigue, hypokalemia, anemia, and vomiting.

Palliative Treatment of Patients with Multiple Myeloma

The safety of melphalan was evaluated in 295 patients with multiple myeloma in the randomized clinical trial [see Clinical Studies (14)]. One hundred and ninety-five patients were administered intravenous melphalan at a dosage of 16 mg/m2

q 2 weeks x 4 (over 6 weeks) followed by the same dose every 4 weeks. One hundred patients were administered oral melphalan at a dosage of 0.15 mg/kg/day x 7 followed by 0.05 mg/kg/day when WBC counts began to rise.

Severe myelotoxicity (WBC ≤1,000 and/or platelets ≤25,000) was more common in the intravenous melphalan arm (28%) than in the oral melphalan arm (11%).

7.1 Effect of Other Drugs on IVRA

Cisplatin

Concomitant use with cisplatin may alter melphalan clearance by inducing renal dysfunction. Consider intravenous IVRA dosage reduction in patients with renal insufficiency following concomitant use with cisplatin [see Dosage and Administration (2.2)].

7.2 Effect of IVRA on Other Drugs

BCNU

Concomitant use with BCNU may reduce the threshold for lung toxicity. Monitor for increased lung toxicity.

7.3 Cyclosporine

Concomitant use with cyclosporine may increase the risk of developing severe renal failure [see Clinical Pharmacology (12.3)]. Consider intravenous IVRA dosage reduction in patients with renal insufficiency following concomitant use with cyclosporine [see Dosage and Administration (2.2)].

8.1 Pregnancy

Risk Summary

Based on its mechanism of action and findings from animal studies, IVRA can cause fetal harm when administered to a pregnant woman. There are no available data on IVRA use in pregnant women to evaluate for a drug-associated risk. In rats, melphalan was embryolethal and teratogenic at doses lower than the highest recommended clinical dose (see Data). If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential risk to the fetus.

The background risk in the U.S. general population of major birth defects is 2 to 4% and of miscarriage is 15 to 20% of clinically recognized pregnancies.

Data

Animal Data

Adequate animal studies have not been conducted with intravenous melphalan. Melphalan was embryolethal and teratogenic in rats following oral administration of 6 to 18 mg/m2/day for 10 days (0.06 to 0.18 times the highest recommended clinical dose of 100 mg/m2/day) and intraperitoneal administration of 18 mg/m2 (0.18 times the highest recommended clinical dose). Malformations resulting from melphalan administration included alterations of the brain (underdevelopment, deformation, meningocele, and encephalocele) and eye (anophthalmia and microphthalmos), reduction of the mandible and tail, and hepatocele (exomphaly).

8.2 Lactation

Risk Summary

There are no data on the presence of melphalan in human milk, the effects on the breastfed child, or the effects on milk production. Because of the potential for serious adverse reactions in a breastfed child, advise women not to breastfeed during treatment with IVRA and for 1 week following the last dose.

8.3 Females and Males of Reproductive Potential

IVRA can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)].

Contraception

Females

Advise females of reproductive potential to use effective contraception during treatment with IVRA and for 6 months after the last dose.

Males

Melphalan may damage spermatozoa and testicular tissue, resulting in possible genetic fetal abnormalities. Advise males with female partners of reproductive potential to use effective contraception during treatment with IVRA and for 3 months after the last dose [see Nonclinical Toxicology (13.1)].

Infertility

Females

Melphalan causes suppression of ovarian function in premenopausal women, resulting in amenorrhea in a significant number of patients.

Males

Reversible and irreversible testicular suppression has been reported in male patients after administration of melphalan.

8.4 Pediatric Use

The safety and effectiveness of IVRA in pediatric patients have not been established.

8.5 Geriatric Use

Clinical studies of melphalan did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

8.6 Renal Impairment

Consider a dosage reduction in patients with renal insufficiency receiving intravenous IVRA [see Dosage and Administration (2.2)]. In one trial, increased bone marrow suppression was observed in patients with elevated BUN [see Clinical Pharmacology (12.3)].

12.1 Mechanism of Action

Melphalan is an alkylating agent of the bischloroethylamine type. As a result, its cytotoxicity appears to be related to the extent of its interstrand cross-linking with DNA, probably by binding at the N7 position of guanine. Like other bifunctional alkylating agents, it is active against both resting and rapidly dividing tumor cells.

12.2 Pharmacodynamics

Due to lack of information, melphalan exposure-response relationships and the time course of pharmacodynamic response are unknown.

12.3 Pharmacokinetics

The mean ±SD melphalan peak plasma concentration is 1.2 ± 0.4 following an intravenous dosage of 10 mg/m2 (0.62 times the approved recommended dosage) and 2.8 ± 1.9 mcg/mL following an intravenous dosage of 20 mg/m2 (1.25 times the approved recommended dosage) in myeloma patients.

Distribution

The melphalan steady-state volume of distribution is 0.5 L/kg. Melphalan penetration into cerebrospinal fluid (CSF) is low.

The mean melphalan plasma protein binding ranges from 53% to 92% with approximately 30% irreversible (covalent). Serum albumin accounts for approximately 40% to 60% and α1-acid glycoprotein approximately 20% of the plasma protein binding.

Elimination

The melphalan elimination half-life is approximately 75 minutes. Mean total body melphalan clearance varied among studies, but typical values of approximately 7 to 9 mL/min/kg (250 to 325 mL/min/m2) were observed.

Metabolism

Melphalan primarily metabolized by hydrolysis to monohydroxymelphalan and dihydroxymelphalan, which are inactive.

Excretion

Following a radiolabeled dose of intravenous melphalan in 9 patients with cancer, the mean (± SD) excretion of melphalan over 24 hours was 13% ± 5.4% of the total dose.  

Specific Populations

Patients with renal Impairment

Although melphalan renal clearance appears to be low, one study reported an increase in the occurrence of severe leukopenia in patients with BUN levels ≥30 mg/dL after 10 weeks of therapy. A 50% reduction in the IV melphalan dosage decreased the incidence of severe bone marrow suppression in the latter portion of this study.

Drug Interaction Studies

Cyclosporine

Patients treated with a single dose of intravenous melphalan followed by standard oral doses of cyclosporine were reported to develop severe renal failure.

Immunoglobulins

Interactions between melphalan and immunoglobulins are negligible.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Adequate and well-controlled carcinogenicity studies with melphalan have not been conducted in animals. However, intraperitoneal (IP) administration of melphalan in rats (5.4 to 10.8 mg/m2) and in mice (2.25 to 4.5 mg/m2) 3 times per week for 6 months followed by 12 months post-dose observation produced peritoneal sarcoma and lung tumors, respectively.

Intramuscular administration of melphalan at 6 and 60 mg/m2 produced structural aberrations of the chromatid and chromosomes in bone marrow cells of Wistar rats.