FDA Approves Merck’s NOXAFIL® (posaconazole) Injection (18 mg/mL) for Intravenous Use

Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the U.S. Food and Drug Administration has approved NOXAFIL® (posaconazole) injection (18 mg/ mL), a new formulation of NOXAFIL for intravenous (IV) use. Merck’s antifungal agent is also marketed as NOXAFIL (100 mg) delayed-release tablets and NOXAFIL (40 mg/mL) oral suspension. NOXAFIL injection, delayed-release tablets and oral suspension are indicated for prophylaxis of invasive Aspergillus and Candida infections in patients who are at high risk of developing these infections due to being severely immunocompromised, such as hematopoietic stem cell transplant (HSCT) recipients with graft-versus-host disease (GVHD) or those with hematologic malignancies with prolonged neutropenia (low white blood cell counts) from chemotherapy. NOXAFIL injection is indicated in patients 18 years of age and older. NOXAFIL delayed-release tablets and oral suspension are indicated in patients 13 years of age and older. With this approval, Merck now provides an IV formulation and two oral formulations of NOXAFIL for prophylaxis against invasive Aspergillus and Candida infections in high-risk patients.

NOXAFIL should not be administered to persons allergic to posaconazole or other azole antifungal medicines. The administration of NOXAFIL with sirolimus, pimozide, quinidine, atorvastatin, lovastatin, simvastatin and ergot alkaloids must be avoided. When administered with NOXAFIL, some drugs such as cyclosporine and tacrolimus required dosage adjustments and frequent monitoring of their levels in the blood as serious side effects in the kidney (nephrotoxicity) or brain (leukoencephalopathy) including deaths have been reported in patients with increased cyclosporine or tacrolimus blood levels. NOXAFIL should be administered with caution to patients who may develop an irregular heart rhythm as NOXAFIL has been shown to prolong the QT interval and cases of potentially fatal irregular heart rhythm (torsades de pointes) have been reported in patients taking NOXAFIL (posaconazole). (See Selected Safety Information below.)

“Merck is pleased to add NOXAFIL injection to the NOXAFIL family of products. The availability of a NOXAFIL formulation for intravenous administration is particularly important for those patients who may benefit from or require intravenous therapy, or who, for a variety of reasons, might not be able to take an oral formulation. In addition, patients have the possibility to start on NOXAFIL injection and transition to oral NOXAFIL,” said Dr. Nicholas Kartsonis, executive director, Infectious Disease, Merck Research Laboratories.

NOXAFIL injection offers patients once-daily maintenance dosing following a twice-daily loading dose on the first day of NOXAFIL therapy. NOXAFIL injection is administered with a loading dose of 300 mg (one 300 mg vial) twice a day on the first day of NOXAFIL therapy, then 300 mg (one 300 mg vial) once a day thereafter. Once combined with a mixture of intravenous solution (150 mL of 5% dextrose in water or sodium chloride 0.9%), NOXAFIL injection should be immediately administered through an in-line filter. Administer NOXAFIL through a central venous line by slow IV infusion over approximately 90 minutes. If not used immediately, the solution can be stored up to 24 hours refrigerated at 2-8 degrees C (36-46 degrees F). Coadministration of drugs that can decrease the plasma concentration of posaconazole should generally be avoided unless the benefit outweighs the risk. If such drugs are necessary, patients should be monitored closely for breakthrough fungal infections.

In clinical trials, the adverse reactions reported for NOXAFIL IV injection were generally similar in type to that reported in trials of NOXAFIL oral suspension. The most frequently reported adverse reactions with an onset during the posaconazole intravenous phase of dosing 300 mg once-daily therapy were diarrhea (32%), hypokalemia (22%), fever (21%) and nausea (19%).

NOXAFIL injection is expected to be available at wholesalers in mid-April.

Selected Safety Information

NOXAFIL is contraindicated in persons with known hypersensitivity to posaconazole or other azole antifungal agents.

NOXAFIL is contraindicated with sirolimus. Concomitant administration of NOXAFIL with sirolimus increases the sirolimus blood concentrations by approximately 9-fold and can result in sirolimus toxicity.

NOXAFIL is contraindicated with CYP3A4 substrates that prolong the QT interval. Concomitant administration of NOXAFIL with the CYP3A4 substrates, pimozide and quinidine may result in increased plasma concentrations of these drugs, leading to QT prolongation and cases of torsades de pointes.

NOXAFIL (posaconazole) is contraindicated with HMG-CoA reductase inhibitors that are primarily metabolized through CYP3A4 (e.g., atorvastatin, lovastatin and simvastatin) as increased plasma concentration of these drugs can lead to rhabdomyolysis.

NOXAFIL is contraindicated with ergot alkaloids. NOXAFIL may increase the plasma concentrations of ergot alkaloids (ergotamine and dihydroergotamine) which may lead to ergotism.

Concomitant administration of NOXAFIL with cyclosporine or tacrolimus increases the whole blood trough concentrations of these calcineurin inhibitors. Nephrotoxicity and leukoencephalopathy (including deaths) have been reported in clinical efficacy studies in patients with elevated cyclosporine or tacrolimus concentrations. Frequent monitoring of cyclosporine or tacrolimus whole blood trough concentrations should be performed during and at discontinuation of NOXAFIL treatment and the tacrolimus or cyclosporine dose adjusted accordingly.

Some azoles, including NOXAFIL, have been associated with prolongation of the QT interval on the electrocardiogram. In addition, cases of torsades de pointes have been reported in patients taking NOXAFIL. NOXAFIL should be administered with caution to patients with potentially proarrhythmic conditions. Do not administer with drugs that are known to prolong the QT interval and are metabolized through CYP3A4. Rigorous attempts to correct potassium, magnesium and calcium should be made in these patients before starting NOXAFIL.

Hepatic reactions (e.g., mild to moderate elevations in ALT, AST, alkaline phosphatase, total bilirubin and/or clinical hepatitis) have been reported in clinical trials. The elevations in liver function tests were generally reversible on discontinuation of therapy, and in some instances these tests normalized without drug interruption. Cases of more severe hepatic reactions including cholestasis or hepatic failure including deaths have been reported in patients with serious underlying medical conditions (e.g., hematologic malignancy) during treatment with NOXAFIL. Liver function tests should be evaluated at the start of and during the course of therapy. Patients who develop abnormal liver function tests during posaconazole therapy should be monitored for the development of more severe hepatic injury. Consider discontinuation of NOXAFIL if clinical signs and symptoms consistent with liver disease develop that may be attributable to NOXAFIL.

Due to the variability in exposure with NOXAFIL delayed-release tablets and oral suspension, patients with severe renal impairment should be monitored closely for breakthrough fungal infections. NOXAFIL (posaconazole) injection should be avoided in patients with moderate or severe renal impairment (estimated glomerular filtration rate [eGFR] <50 mL/min), unless an assessment of the benefit/risk to the patient justifies the use of NOXAFIL injection. In patients with moderate or severe renal impairment (eGFR <50 mL/min), receiving the NOXAFIL injection, accumulation of the intravenous vehicle, Betadex Sulfobutyl Ether Sodium (SBECD), is expected to occur. Serum creatinine levels should be closely monitored in these patients, and, if increases occur, consideration should be given to changing to oral NOXAFIL therapy.

Concomitant administration of NOXAFIL with midazolam increases the midazolam plasma concentrations by approximately 5-fold which could potentiate and prolong hypnotic and sedative effects. Concomitant use of NOXAFIL and other benzodiazepines metabolized by CYP3A4 (e.g., alprazolam, triazolam) could result in increased plasma concentrations of these benzodiazepines. Patients must be monitored closely for adverse effects associated with high plasma concentrations of midazolam and other benzodiazepines metabolized by CYP3A4. In addition, benzodiazepine receptor antagonists must be available to reverse these effects.

Posaconazole is primarily metabolized via UDP glucuronosyltransferase and is a substrate of p-glycoprotein (P-gp) efflux. Therefore, inhibitors or inducers of these clearance pathways may affect posaconazole plasma concentrations. Coadministration of drugs that can decrease the plasma concentrations of posaconazole should generally be avoided unless the benefit outweighs the risk. If such drugs are necessary, patients should be monitored closely for breakthrough fungal infections. Posaconazole is also a strong inhibitor of CYP3A4. Therefore, plasma concentrations of drugs predominantly metabolized by CYP3A4 may be increased by posaconazole.

Coadministration of NOXAFIL with rifabutin, phenytoin and efavirenz should be avoided unless the benefit outweighs the risk. Monitoring for toxicity and/or adverse events is recommended when tacrolimus, cyclosporine, benzodiazepines, ritonavir, atazanavir, vinca alkaloids and calcium channel blockers and rifabutin are coadministered with NOXAFIL. Dosage adjustments should also be considered when tacrolimus, cyclosporine, vinca alkaloids, calcium channel blockers and phenytoin are administered with NOXAFIL. Monitor plasma concentrations when coadministering digoxin, phenytoin, tacrolimus and cyclosporine with NOXAFIL. Although no dosage adjustment of glipizide is required, it is recommended to monitor glucose concentrations when coadministering glipizide with NOXAFIL. Monitor for breakthrough fungal infections when coadministering fosamprenavir, rifabutin and phenytoin with NOXAFIL.

Coadministration of NOXAFIL oral suspension with cimetidine (an H2-receptor antagonist) and esomeprazole (a proton pump inhibitor) results in lower posaconazole plasma concentrations and should be avoided unless the benefit outweighs the risk. No clinically relevant effects were observed when posaconazole oral suspension is concomitantly used with antacids and H2-receptor antagonists other than cimetidine.

Coadministration of NOXAFIL (posaconazole) oral suspension with metoclopramide decreases posaconazole plasma concentrations; however loperamide does not affect posaconazole plasma concentrations. Monitor for breakthrough fungal infections when coadministering cimetidine, esomeprazole and metoclopramide with NOXAFIL oral suspension.

No clinically relevant effects on the pharmacokinetics of posaconazole delayed-release tablets were observed when concomitantly administered with drugs affecting gastric pH (i.e., antacids, H2-receptor antagonists, proton pump inhibitors). Concomitant administration of metoclopramide with posaconazole delayed-release tablets did not affect the pharmacokinetics of posaconazole.

The safety and effectiveness of NOXAFIL injection in patients below the age of 18 years old have not been established. NOXAFIL injection should not be used in pediatric patients because of non-clinical safety concerns.

The safety and effectiveness of NOXAFIL delayed-release tablets and oral suspension in pediatric patients below the age of 13 years old have not been established.

No dose adjustment in NOXAFIL is needed in patients with mild to severe hepatic insufficiency (Child-Pugh Class A, B, and C). Discontinuation of NOXAFIL must be considered in patients who experience clinical signs and symptoms consistent with liver disease that may be attributable to NOXAFIL.

Patients weighing greater than 120 kg may have lower posaconazole plasma drug exposures. It is therefore, suggested to closely monitor for breakthrough fungal infections.

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Please see Prescribing Information for NOXAFIL (posaconazole) IV injection, delayed-release tablets and oral suspension at http://www.spfiles.com/pinoxafil.pdf and Patient Information for NOXAFIL at http://www.spfiles.com/ppinoxafil.pdf.

NOXAFIL® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Whitehouse Station, N.J., USA.