Rezafungin (Monograph)

Brand name: Rezzayo
Drug class: Echinocandins

Introduction

Antifungal; echinocandin.

Uses for Rezafungin

Candidemia and Invasive Candidemia

Treatment of candidemia and invasive candidiasis in adults ≥18 years of age who have limited or no alternative treatment options. Approval is based on limited clinical safety and efficacy data.

Designated an orphan drug for the treatment of candidemia and invasive candidiasis caused by susceptible Candida species.

Not studied in patients with endocarditis, osteomyelitis, and meningitis due to Candida.

Echinocandins (e.g., anidulafungin, caspofungin, micafungin) are recommended as first-line drugs for most types of invasive candidiasis.

Rezafungin has been shown to be noninferior to IV caspofungin in the management of candidemia and/or invasive candidiasis. The extended half-life of rezafungin and broad spectrum of activity may provide some advantages over other currently available echinocandins; however, place of therapy is not yet discussed in clinical practice guidelines.

Rezafungin Dosage and Administration

General

Pretreatment Screening

Obtain specimens for culture and other laboratory data (e.g., histopathology, non-culture diagnostics) prior to initiating antifungal therapy.
Therapy may be initiated before the results of cultures and other laboratory tests are known but should be adjusted once these results become available.

Patient Monitoring

Monitor patients who develop abnormal liver tests during therapy and evaluate patients for the risk/benefit of continuing therapy.
Monitor for infusion-related reactions, including flushing, sensation of warmth, urticaria, nausea, or chest tightness.
Monitor for photosensitivity reactions and advise patients to use protection against sun exposure and other sources of UV radiation during treatment.

Administration

IV Administration

Administer by IV infusion.

Do not administer by rapid IV injection.

Reconstitution and Dilution

Must reconstitute and further dilute commercially available lyophilized powder prior to administration.

For a dose of 400 mg, reconstitute two vials each with 9.5 mL of sterile water for injection. For a dose of 200 mg, reconstitute one vial with 9.5 mL of sterile water for injection.

Gently swirl vial(s) to dissolve powder; do not shake. The solution should be clear to pale yellow after dissolution; do not use if cloudy or precipitated.

To prepare the IV infusion solution, withdraw and discard the appropriate volume of diluent from an IV bag containing 250 mL of 0.9% sodium chloride injection, 0.45% sodium chloride injection, or 5% dextrose injection; then transfer the required volume of reconstituted solution (10 mL for a dose of 200 mg and 20 mL for a dose of 400 mg) into the IV bag to provide an infusion concentration of 0.8 mg/mL for a dose of 200 mg or 1.6 mg/mL for a dose of 400 mg.

Rate of Administration

Infuse IV rezafungin over approximately 1 hour (approximately 250 mL/h).

If an infusion-related reaction occurs, the infusion may be slowed, or paused and restarted at a lower rate.

Dosage

Adults

Candidemia and Invasive Candidemia

IV

Initial 400 mg loading dose followed by 200 mg once weekly thereafter.

Safety not established beyond 4 weekly doses.

If a dose is missed, administer missed dose as soon as possible. If missed dose is administered within 3 days of assigned day, administer next weekly dose on schedule. However, if missed dose is administered more than 3 days after assigned day, revise dosing schedule to ensure that there is at least 4 days before next dose. A 400 mg loading dose is required if rezafungin is restarted after at least 2 weeks of missed doses.

Special Populations

Hepatic Impairment

No specific dosage recommendations.

Renal Impairment

No specific dosage recommendations.

Geriatric Patients

No specific dosage recommendations.

Cautions for Rezafungin

Contraindications

Known hypersensitivity to rezafungin or other echinocandins.

Warnings/Precautions

Infusion-related Reactions

Infusion-related reactions, including flushing, sensation of warmth, urticaria, nausea, and chest tightness observed. If these reactions occur, slow or pause the infusion and restart at a lower rate.

Photosensitivity

May cause photosensitivity. Advise patients to use protection from sun exposure and other sources of UV radiation during treatment.

Hepatic Effects

Abnormalities in liver tests reported and in some cases were clinically significant. Monitor patients who develop abnormal liver tests during therapy and evaluate risk/benefit of continuing therapy.

Specific Populations

Pregnancy

No data on use during pregnancy to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes.

Lactation

No data on presence of rezafungin or its metabolite in human milk; distributes into milk in rats.

Consider developmental and health benefits of breastfeeding along with mother’s clinical need for rezafungin and any potential adverse effects of the drug on breastfed infant.

Females and Males of Reproductive Potential

In animal studies, decreased sperm motility, decreased sperm numbers, and abnormal sperm morphology observed. Effect on human fertility is unknown.

Pediatric Use

Safety and effectiveness not established.

Geriatric Use

Insufficient numbers of older adults in clinical studies to determine if patients ≥65 years respond differently than younger adult patients.

No clinically relevant effects of age (ranging from 20 to 89 years) observed on the pharmacokinetics of rezafungin.

Hepatic Impairment

No clinically relevant effects of hepatic impairment (Child Pugh Class B or C) observed on pharmacokinetics of rezafungin.

Renal Impairment

No clinically relevant effects of renal impairment (Cl_cr 9.3 to >120 mL/minute) on pharmacokinetics of rezafungin.

Common Adverse Effects

Adverse events (≥5%): hypokalemia, pyrexia, diarrhea, anemia, vomiting, nausea, hypomagnesemia, abdominal pain, constipation, hypophosphatemia.

Drug Interactions

Does not undergo hepatic metabolism.

Not a substrate for CYP isoenzymes or drug transporter systems.

Not an inhibitor or inducer of common CYP isoenzymes or drug transporters.

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

Pharmacokinetic interactions unlikely with drugs metabolized by CYP2C8 (e.g., repaglinide), CYP3A (e.g., cyclosporine, tacrolimus, midazolam), and CYP1A2 (e.g., caffeine).

Drugs Affecting or Affected by Transport Systems

Pharmacokinetic interactions unlikely with drugs affected by P-glycoprotein (P-gp; e.g., cyclosporine, tacrolimus, digoxin), organic cation transporter (OCT-1, OCT-2; e.g., metformin), multidrug and toxin extrusion (MATE-1, MATE-2; e.g., metformin), organic anion transporter peptide (OATP; e.g., pitavastatin, rosuvastatin), and Breast Cancer Resistance Protein (BCRP; e.g., rosuvastatin).

Other Commonly Co-administered Drugs

No clinically significant effects of rezafungin on pharmacokinetics of other drugs likely to be co-administered (e.g., ibrutinib, venetoclax, efavirenz, mycophenolate mofetil).

Rezafungin Pharmacokinetics

Absorption

Plasma Concentrations

Following single and multiple IV dosing, peak plasma concentrations increase in a dose-proportional manner over dose range of 50 to 400 mg.

Distribution

Plasma Protein Binding

Ranges from 87.5 to 93.6%.

Elimination

Metabolism

Not hepatically metabolized.

Elimination Route

Mainly eliminated via feces (approximately 74.3% of parent drug); remainder (25.7%) is eliminated in the urine primarily as inactive metabolites.

Half-life

Terminal half-life approximately 152 hours.

Stability

Storage

Parenteral

Single-dose Vials For Injection

Store vials at 20–25°C (brief exposure to 15–30°C permitted).

Store reconstituted solution at 5–25°C for up to 24 hours.

Store IV infusion solution between 5–25°C for up to 48 hours; do not freeze.

Actions

Echinocandin antifungal. Semisynthetic lipopeptide synthesized from a fermentation product of Aspergillus nidulans.
Inhibits 1,3-β-D-glucan synthase enzyme complex, which is present in fungal cell walls but not in mammalian cells.
Inhibition of 1,3-β-D-glucan synthesis results in concentration-dependent in vitro fungicidal activity against Candida spp.; however, clinical significance of this activity is unknown.
Echinocandins (e.g., anidulafungin, caspofungin, micafungin) differ structurally and pharmacologically from other available antifungals.
Exhibits concentration-dependent fungicidal activity in vitro. Fungicidal killing is correlated to AUC relative to MIC.
Active against most isolates of C. albicans, C. glabrata, C. parapsilosis, and C. tropicalis.
Also exhibits in vitro activity against C. krusei, C. auris, C. dubliniensis, C. fabianii, C. guilliermondii, C. inconspicua, C. kefyr, C. lusitaniae, C. metapsilosis, C. orthopsilosis, C. pulcherrima, C.rugosa, and C. sojae , although clinical significance not known.
Reduced susceptibility to echinocandins has been associated with specific mutations in FKS subunits of the glucan synthase enzyme. These mutations are associated with higher MICs and poor response to therapy.

Advice to Patients

Advise patients to use protection against sun exposure and other sources of UV radiation during treatment because rezafungin may cause photosensitivity.
Advise patients to inform their clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as any concomitant illnesses.
Advise patients to inform their clinician if they are or plan to become pregnant or plan to breast-feed.
Inform patients of other important precautionary information.

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer’s labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Rezafungin is obtained through designated specialty pharmacies. Contact the manufacturer or consult the Rezzayo website ([Web]) for specific availability information.