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Virenza

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Virenza uses


1 INDICATIONS AND USAGE

Virenza, an influenza neuraminidase inhibitor, is indicated for:

Treatment of influenza in patients aged 7 years and older who have been symptomatic for no more than 2 days. (1.1)

Prophylaxis of influenza in patients aged 5 years and older. (1.2)

Important Limitations on Use of Virenza:

Not recommended for treatment or prophylaxis of influenza in:


Not proven effective for:


Not a substitute for annual influenza vaccination. (1.3)

Consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use Virenza. (1.3)

1.1 Treatment of Influenza

Virenza® (zanamivir) inhalation powder is indicated for treatment of uncomplicated acute illness due to influenza A and B virus in adults and pediatric patients aged 7 years and older who have been symptomatic for no more than 2 days.

1.2 Prophylaxis of Influenza

Virenza is indicated for prophylaxis of influenza in adults and pediatric patients aged 5 years and older.

1.3 Important Limitations on Use of Virenza

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2 DOSAGE AND ADMINISTRATION


Indication


Dose


Treatment of Influenza


10 mg twice daily for 5 days

Prophylaxis: (2.3)

Household Setting

10 mg once daily for 10 days

Community Outbreaks

10 mg once daily for 28 days

Note: The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation). (2.1)

2.1 Dosing Considerations

2.2 Treatment of Influenza

2.3 Prophylaxis of Influenza

Household Setting


Community Outbreaks

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3 DOSAGE FORMS AND STRENGTHS

Blister for oral inhalation: 5 mg. Four 5-mg blisters of powder on a ROTADISK® for oral inhalation via DISKHALER. Packaged in carton containing 5 ROTADISKs (total of 10 doses) and 1 DISKHALER inhalation device .

Blister for oral inhalation: 5 mg. Four 5-mg blisters of powder on a ROTADISK for oral inhalation via DISKHALER. Packaged in carton containing 5 ROTADISKs (total of 10 doses) and 1 DISKHALER inhalation device. (3)

4 CONTRAINDICATIONS

Do not use in patients with history of allergic reaction to any ingredient of Virenza including milk proteins .

Do not use in patients with history of allergic reaction to any ingredient of Virenza, including milk proteins. (4)

5 WARNINGS AND PRECAUTIONS

5.1 Bronchospasm

Virenza is not recommended for treatment or prophylaxis of influenza in individuals with underlying airways disease (such as asthma or chronic obstructive pulmonary disease).

Serious cases of bronchospasm, including fatalities, have been reported during treatment with Virenza in patients with and without underlying airways disease. Many of these cases were reported during postmarketing and causality was difficult to assess.

Virenza should be discontinued in any patient who develops bronchospasm or decline in respiratory function; immediate treatment and hospitalization may be required.

Some patients without prior pulmonary disease may also have respiratory abnormalities from acute respiratory infection that could resemble adverse drug reactions or increase patient vulnerability to adverse drug reactions.

Bronchospasm was documented following administration of Virenza in 1 of 13 subjects with mild or moderate asthma (but without acute influenza-like illness) in a Phase I trial. In a Phase III trial in subjects with acute influenza-like illness superimposed on underlying asthma or chronic obstructive pulmonary disease, 10% (24 of 244) of subjects on Virenza and 9% (22 of 237) on placebo experienced a greater than 20% decline in FEV1 following treatment for 5 days.

If use of Virenza is considered for a patient with underlying airways disease, the potential risks and benefits should be carefully weighed. If a decision is made to prescribe Virenza for such a patient, this should be done only under conditions of careful monitoring of respiratory function, close observation, and appropriate supportive care including availability of fast-acting bronchodilators.

5.2 Allergic Reactions

Allergic-like reactions, including oropharyngeal edema, serious skin rashes, and anaphylaxis have been reported in postmarketing experience with Virenza. Virenza should be stopped and appropriate treatment instituted if an allergic reaction occurs or is suspected.

5.3 Neuropsychiatric Events

Influenza can be associated with a variety of neurologic and behavioral symptoms which can include events such as seizures, hallucinations, delirium, and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease.

There have been postmarketing reports of delirium and abnormal behavior leading to injury in patients with influenza who were receiving NAIs, including Virenza. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made, but they appear to be uncommon based on usage data for Virenza. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of Virenza to these events has not been established. Patients with influenza should be closely monitored for signs of abnormal behavior. If neuropsychiatric symptoms occur, the risks and benefits of continuing treatment should be evaluated for each patient.

5.4 Limitations of Populations Studied

Safety and efficacy have not been demonstrated in patients with high-risk underlying medical conditions. No information is available regarding treatment of influenza in patients with any medical condition sufficiently severe or unstable to be considered at imminent risk of requiring inpatient management.

5.5 Bacterial Infections

Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza. Virenza has not been shown to prevent such complications.

5.6 Importance of Proper Route of Administration

Virenza inhalation powder must not be made into an extemporaneous solution for administration by nebulization or mechanical ventilation. There have been reports of hospitalized patients with influenza who received a solution made with Virenza inhalation powder administered by nebulization or mechanical ventilation, including a fatal case where it was reported that the lactose in this formulation obstructed the proper functioning of the equipment. Virenza inhalation powder must only be administered using the device provided .

5.7 Importance of Proper Use of DISKHALER

Effective and safe use of Virenza requires proper use of the DISKHALER to inhale the drug. Prescribers should carefully evaluate the ability of young children to use the delivery system if use of Virenza is considered .

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6 ADVERSE REACTIONS

See Warnings and Precautions for information about risk of serious adverse events such as bronchospasm and allergic-like reactions (5.2), and for safety information in patients with underlying airways disease (5.1).

The most common adverse events reported in greater than 1.5% of subjects treated with Virenza and more commonly than in subjects treated with placebo are:

6.1 Clinical Trials Experience

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

The placebo used in clinical trials consisted of inhaled lactose powder, which is also the vehicle for the active drug; therefore, some adverse events occurring at similar frequencies in different treatment groups could be related to lactose vehicle inhalation.

Treatment of Influenza

Clinical Trials in Adults and Adolescents: Adverse events that occurred with an incidence greater than or equal to 1.5% in treatment trials are listed in Table 1. This table shows adverse events occurring in subjects aged 12 years and older receiving Virenza 10 mg inhaled twice daily, Virenza in all inhalation regimens, and placebo inhaled twice daily (where placebo consisted of the same lactose vehicle used in Virenza).


Adverse Event


Virenza


Placebo

(Lactose Vehicle)

(n = 1,520)


10 mg b.i.d. Inhaled

(n = 1,132)


All Dosing Regimensa

(n = 2,289)


Body as a whole


Headaches

2%

2%

3%

Digestive


Diarrhea

3%

3%

4%

Nausea

3%

3%

3%

Vomiting

1%

1%

2%

Respiratory


Nasal signs and symptoms

2%

3%

3%

Bronchitis

2%

2%

3%

Cough

2%

2%

3%

Sinusitis

3%

2%

2%

Ear, nose, and throat infections

2%

1%

2%

Nervous system


Dizziness

2%

1%

<1%

a Includes trials where Virenza was administered intranasally (6.4 mg 2 to 4 times per day in addition to inhaled preparation) and/or inhaled more frequently (q.i.d.) than the currently recommended dose.

Additional adverse reactions occurring in less than 1.5% of subjects receiving Virenza included malaise, fatigue, fever, abdominal pain, myalgia, arthralgia, and urticaria.

The most frequent laboratory abnormalities in Phase III treatment trials included elevations of liver enzymes and CPK, lymphopenia, and neutropenia. These were reported in similar proportions of Virenza and lactose vehicle placebo recipients with acute influenza-like illness.

Clinical Trials in Pediatric Subjects: Adverse events that occurred with an incidence greater than or equal to 1.5% in children receiving treatment doses of Virenza in 2 Phase III trials are listed in Table 2. This table shows adverse events occurring in pediatric subjects aged 5 to 12 years receiving Virenza 10 mg inhaled twice daily and placebo inhaled twice daily (where placebo consisted of the same lactose vehicle used in Virenza).


Adverse Event


Virenza

10 mg b.i.d. Inhaled

(n = 291)


Placebo

(Lactose Vehicle)

(n = 318)


Respiratory


Ear, nose, and throat infections

5%

5%

Ear, nose, and throat hemorrhage

<1%

2%

Asthma

<1%

2%

Cough

<1%

2%

Digestive


Vomiting

2%

3%

Diarrhea

2%

2%

Nausea

<1%

2%

a Includes a subset of subjects receiving Virenza for treatment of influenza in a prophylaxis trial.

In 1 of the 2 trials described in Table 2, some additional information is available from children (aged 5 to 12 years) without acute influenza-like illness who received an investigational prophylaxis regimen of Virenza; 132 children received Virenza and 145 children received placebo. Among these children, nasal signs and symptoms (zanamivir 20%, placebo 9%), cough (zanamivir 16%, placebo 8%), and throat/tonsil discomfort and pain (zanamivir 11%, placebo 6%) were reported more frequently with Virenza than placebo. In a subset with chronic pulmonary disease, lower respiratory adverse events (described as asthma, cough, or viral respiratory infections which could include influenza-like symptoms) were reported in 7 of 7 Virenza recipients and 5 of 12 placebo recipients.

Prophylaxis of Influenza

Family/Household Prophylaxis Studies: Adverse events that occurred with an incidence of greater than or equal to 1.5% in the 2 prophylaxis trials are listed in Table 3. This table shows adverse events occurring in subjects aged 5 years and older receiving Virenza 10 mg inhaled once daily for 10 days.


Adverse Event


Contact Cases


Virenza

(n = 1,068)


Placebo

(n = 1,059)


Lower respiratory


Viral respiratory infections

13%

19%

Cough

7%

9%

Neurologic


Headaches

13%

14%

Ear, nose, and throat


Nasal signs and symptoms

12%

12%

Throat and tonsil discomfort and pain

8%

9%

Nasal inflammation

1%

2%

Musculoskeletal


Muscle pain

3%

3%

Endocrine and metabolic


Feeding problems (decreased or increased appetite and anorexia)

2%

2%

Gastrointestinal


Nausea and vomiting

1%

2%

Non-site specific


Malaise and fatigue

5%

5%

Temperature regulation disturbances (fever and/or chills)

5%

4%

a In prophylaxis trials, symptoms associated with influenza-like illness were captured as adverse events; subjects were enrolled during a winter respiratory season during which time any symptoms that occurred were captured as adverse events.

Community Prophylaxis Trials: Adverse events that occurred with an incidence of greater than or equal to 1.5% in 2 prophylaxis trials are listed in Table 4. This table shows adverse events occurring in subjects aged 5 years and older receiving Virenza 10 mg inhaled once daily for 28 days.


Adverse Event


Virenza

(n = 2,231)


Placebo

(n = 2,239)


Neurologic


Headaches

24%

26%

Ear, nose, and throat


Throat and tonsil discomfort and pain

19%

20%

Nasal signs and symptoms

12%

13%

Ear, nose, and throat infections

2%

2%

Lower respiratory


Cough

17%

18%

Viral respiratory infections

3%

4%

Musculoskeletal


Muscle pain

8%

8%

Musculoskeletal pain

6%

6%

Arthralgia and articular rheumatism

2%

<1%

Endocrine and metabolic


Feeding problems (decreased or increased appetite and anorexia)

4%

4%

Gastrointestinal


Nausea and vomiting

2%

3%

Diarrhea

2%

2%

Non-site specific


Temperature regulation disturbances (fever and/or chills)

9%

10%

Malaise and fatigue

8%

8%

a In prophylaxis trials, symptoms associated with influenza-like illness were captured as adverse events; subjects were enrolled during a winter respiratory season during which time any symptoms that occurred were captured as adverse events.

6.2 Postmarketing Experience

In addition to adverse events reported from clinical trials, the following events have been identified during postmarketing use of Virenza (RELENZA). Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to Virenza (RELENZA).

Allergic Reactions

Allergic or allergic-like reaction, including oropharyngeal edema .

Psychiatric

Delirium, including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares.

Cardiac

Arrhythmias, syncope.

Neurologic

Seizures. Vasovagal-like episodes have been reported shortly following inhalation of Virenza.

Respiratory

Bronchospasm, dyspnea .

Skin

Facial edema; rash, including serious cutaneous reactions (e.g., erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis); urticaria .

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7 DRUG INTERACTIONS

Virenza is not a substrate nor does it affect cytochrome P450 (CYP) isoenzymes (CYP1A1/2, 2A6, 2C9, 2C18, 2D6, 2E1, and 3A4) in human liver microsomes. No clinically significant pharmacokinetic drug interactions are predicted based on data from in vitro studies.

The concurrent use of Virenza with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of potential interference between these products, LAIV should not be administered within 2 weeks before or 48 hours after administration of Virenza, unless medically indicated. The concern about possible interference arises from the potential for antiviral drugs to inhibit replication of live vaccine virus.

Trivalent inactivated influenza vaccine can be administered at any time relative to use of Virenza .

Live attenuated influenza vaccine, intranasal (7):

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Pregnancy Category C. There are no adequate and well-controlled studies of Virenza in pregnant women. Virenza should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Embryo/fetal development studies were conducted in rats and rabbits (dosed from Days 7 to 19 of pregnancy) using the same IV doses (1, 9, and 90 mg per kg per day). Pre- and post-natal developmental studies were performed in rats (dosed from Day 16 of pregnancy until litter Day 21 to 23). No malformations, maternal toxicity, or embryotoxicity were observed in pregnant rats or rabbits and their fetuses. Because of insufficient blood sampling timepoints in rat and rabbit reproductive toxicity studies, AUC values were not available. In a subchronic study in rats at the 90-mg-per-kg-per-day IV dose, the AUC values were greater than 300 times the human exposure at the proposed clinical dose.

An additional embryo/fetal study, in a different strain of rat, was conducted using subcutaneous administration of Virenza, 3 times daily, at doses of 1, 9, or 80 mg per kg during Days 7 to 17 of pregnancy. There was an increase in the incidence rates of a variety of minor skeleton alterations and variants in the exposed offspring in this study. Based on AUC measurements, the 80 mg-per-kg dose produced an exposure greater than 1,000 times the human exposure at the proposed clinical dose. However, in most instances, the individual incidence rate of each skeletal alteration or variant remained within the background rates of the historical occurrence in the strain studied.

Virenza has been shown to cross the placenta in rats and rabbits. In these animals, fetal blood concentrations of Virenza were significantly lower than Virenza concentrations in the maternal blood.

8.3 Nursing Mothers

Studies in rats have demonstrated that Virenza is excreted in milk. However, nursing mothers should be instructed that it is not known whether Virenza is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Virenza is administered to a nursing mother.

8.4 Pediatric Use

Treatment of Influenza

Safety and effectiveness of Virenza for treatment of influenza have not been assessed in pediatric patients younger than 7 years, but were studied in a Phase III treatment trial in pediatric subjects, where 471 children aged 5 to 12 years received Virenza or placebo . Adolescents were included in the 3 principal Phase III adult treatment trials. In these trials, 67 patients were aged 12 to 16 years. No definite differences in safety and efficacy were observed between these adolescent patients and young adults.

In a Phase I trial of 16 children aged 6 to 12 years with signs and symptoms of respiratory disease, 4 did not produce a measurable peak inspiratory flow rate (PIFR) through the DISKHALER (3 with no adequate inhalation on request, 1 with missing data), 9 had measurable PIFR on each of 2 inhalations, and 3 achieved measurable PIFR on only 1 of 2 inhalations. Neither of two 6-year-olds and one of two 7-year-olds produced measurable PIFR. Overall, 8 of the 16 children (including all those younger than 8 years) either did not produce measurable inspiratory flow through the DISKHALER or produced peak inspiratory flow rates below the 60 L per min considered optimal for the device under standardized in vitro testing; lack of measurable flow rate was related to low or undetectable serum concentrations . Prescribers should carefully evaluate the ability of young children to use the delivery system if prescription of Virenza is considered.

Prophylaxis of Influenza

The safety and effectiveness of Virenza for prophylaxis of influenza have been studied in 4 Phase III trials where 273 children aged 5 to 11 years and 239 adolescents aged 12 to 16 years received Virenza. No differences in safety and effectiveness were observed between pediatric and adult subjects .

8.5 Geriatric Use

Of the total number of subjects in 6 clinical trials of Virenza for treatment of influenza, 59 subjects were aged 65 years and older, while 24 subjects were aged 75 years and older. Of the total number of subjects in 4 clinical trials of Virenza for prophylaxis of influenza in households and community settings, 954 subjects were aged 65 years and older, while 347 subjects were aged 75 years and older. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger subjects, but greater sensitivity of some older individuals cannot be ruled out. Elderly patients may need assistance with use of the device.

In 2 additional trials of Virenza for prophylaxis of influenza in the nursing home setting, efficacy was not demonstrated .

10 OVERDOSAGE

There have been no reports of overdosage from administration of Virenza.

11 DESCRIPTION

The active component of Virenza is Virenza. The chemical name of Virenza is 5-(acetylamino)-4-[(aminoiminomethyl)-amino]-2,6-anhydro-3,4,5-trideoxy-D-glycero-D-galacto-non-2-enonic acid. It has a molecular formula of C12H20N4O7 and a molecular weight of 332.3. It has the following structural formula:

Virenza is a white to off-white powder for oral inhalation with a solubility of approximately 18 mg per mL in water at 20°C.

Virenza is for administration to the respiratory tract by oral inhalation only. Each Virenza ROTADISK contains 4 regularly spaced double-foil blisters with each blister containing a powder mixture of 5 mg of Virenza and 20 mg of lactose (which contains milk proteins). The contents of each blister are inhaled using a specially designed breath-activated plastic device for inhaling powder called the DISKHALER. After a Virenza ROTADISK is loaded into the DISKHALER, a blister that contains medication is pierced and the Virenza is dispersed into the air stream created when the patient inhales through the mouthpiece. The amount of drug delivered to the respiratory tract will depend on patient factors such as inspiratory flow. Under standardized in vitro testing, Virenza ROTADISK delivers 4 mg of Virenza from the DISKHALER device when tested at a pressure drop of 3 kPa (corresponding to a flow rate of about 62 to 65 L per min) for 3 seconds.

Virenza structural formula

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Virenza is an antiviral drug .

12.3 Pharmacokinetics

Absorption and Bioavailability

Pharmacokinetic studies of orally inhaled Virenza indicate that approximately 4% to 17% of the inhaled dose is systemically absorbed. The peak serum concentrations ranged from 17 to 142 ng per mL within 1 to 2 hours following a 10 mg dose. The area under the serum concentration versus time curve (AUC∞) ranged from 111 to 1,364 ng-hour per mL.

Distribution

Virenza has limited plasma protein binding (less than 10%).

Metabolism

Virenza is renally excreted as unchanged drug. No metabolites have been detected in humans.

Elimination

The serum half-life of Virenza following administration by oral inhalation ranges from 2.5 to 5.1 hours. It is excreted unchanged in the urine with excretion of a single dose completed within 24 hours. Total clearance ranges from 2.5 to 10.9 L per hour. Unabsorbed drug is excreted in the feces.

Impaired Hepatic Function

The pharmacokinetics of Virenza have not been studied in patients with impaired hepatic function.

Impaired Renal Function

After a single intravenous dose of 4 mg or 2 mg of Virenza in volunteers with mild/moderate or severe renal impairment, respectively, significant decreases in renal clearance (and hence total clearance: normals 5.3 L per hour, mild/moderate 2.7 L per hour, and severe 0.8 L per hour; median values) and significant increases in half-life (normals 3.1 hours, mild/moderate 4.7 hours, and severe 18.5 hours; median values) and systemic exposure were observed. Safety and efficacy have not been documented in the presence of severe renal insufficiency. Due to the low systemic bioavailability of Virenza following oral inhalation, no dosage adjustments are necessary in patients with renal impairment. However, the potential for drug accumulation should be considered.

Pediatric Patients

The pharmacokinetics of Virenza were evaluated in pediatric subjects with signs and symptoms of respiratory illness. Sixteen subjects, aged 6 to 12 years, received a single dose of 10 mg Virenza dry powder via DISKHALER. Five subjects had either undetectable Virenza serum concentrations or had low drug concentrations (8.32 to 10.38 ng per mL) that were not detectable after 1.5 hours. Eleven subjects had Cmax median values of 43 ng per mL (range: 15 to 74) and AUC∞ median values of 167 ng-hour per mL (range: 58 to 279). Low or undetectable serum concentrations were related to lack of measurable PIFR in individual subjects .

Geriatric Patients

The pharmacokinetics of Virenza have not been studied in subjects older than 65 years .

Gender, Race, and Weight

In a population pharmacokinetic analysis in patient trials, no clinically significant differences in serum concentrations and/or pharmacokinetic parameters (V/F, CL/F, ka, AUC0-3, Cmax, Tmax, CLr, and % excreted in urine) were observed when demographic variables (gender, age, race, and weight) and indices of infection (laboratory evidence of infection, overall symptoms, symptoms of upper respiratory illness, and viral titers) were considered. There were no significant correlations between measures of systemic exposure and safety parameters.

12.4 Microbiology

Mechanism of Action

Virenza is an inhibitor of influenza virus neuraminidase affecting release of viral particles.

Antiviral Activity

The antiviral activity of Virenza against laboratory and clinical isolates of influenza virus was determined in cell culture assays. The concentrations of Virenza required for inhibition of influenza virus were highly variable depending on the assay method used and virus isolate tested. The 50% and 90% effective concentrations (EC50 and EC90) of Virenza were in the range of 0.005 to 16.0 microM and 0.05 to greater than 100 microM, respectively (1 microM = 0.33 mcg per mL). The relationship between the cell culture inhibition of influenza virus by Virenza and the inhibition of influenza virus replication in humans has not been established.

Resistance

Influenza viruses with reduced susceptibility to Virenza have been selected in cell culture by multiple passages of the virus in the presence of increasing concentrations of the drug. Genetic analysis of these viruses showed that the reduced susceptibility in cell culture to Virenza is associated with mutations that result in amino acid changes in the viral neuraminidase or viral hemagglutinin or both. Resistance mutations selected in cell culture which result in neuraminidase amino acid substitutions include E119G/A/D and R292K. Mutations selected in cell culture in hemagglutinin include: K68R, G75E, E114K, N145S, S165N, S186F, N199S, and K222T.

In an immunocompromised patient infected with influenza B virus, a variant virus emerged after treatment with an investigational nebulized solution of Virenza for 2 weeks. Analysis of this variant showed a hemagglutinin substitution (T198I) which resulted in a reduced affinity for human cell receptors, and a substitution in the neuraminidase active site (R152K) which reduced the enzyme’s activity to Virenza by 1,000-fold. Insufficient information is available to characterize the risk of emergence of Virenza resistance in clinical use.

Cross-Resistance

Cross-resistance has been observed between some zanamivir-resistant and some oseltamivir-resistant influenza virus mutants generated in cell culture. However, some of the in cell culture zanamivir-induced resistance mutations, E119G/A/D and R292K, occurred at the same neuraminidase amino acid positions as in the clinical isolates resistant to oseltamivir, E119V and R292K. No trials have been performed to assess risk of emergence of cross-resistance during clinical use.

Influenza Vaccine Interaction Trial

An interaction trial (n = 138) was conducted to evaluate the effects of Virenza (10 mg once daily) on the serological response to a single dose of trivalent inactivated influenza vaccine, as measured by hemagglutination inhibition titers. There was no difference in hemagglutination inhibition antibody titers at 2 weeks and 4 weeks after vaccine administration between Virenza and placebo recipients.

Influenza Challenge Trials

Antiviral activity of Virenza was supported for infection with influenza A virus, and to a more limited extent for infection with influenza B virus, by Phase I trials in volunteers who received intranasal inoculations of challenge strains of influenza virus, and received an intranasal formulation of Virenza or placebo starting before or shortly after viral inoculation.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

In 2-year carcinogenicity studies conducted in rats and mice using a powder formulation administered through inhalation, Virenza induced no statistically significant increases in tumors over controls. The maximum daily exposures in rats and mice were approximately 23 to 25 and 20 to 22 times, respectively, greater than those in humans at the proposed clinical dose based on AUC comparisons.

Mutagenesis

Virenza was not mutagenic in in vitro and in vivo genotoxicity assays which included bacterial mutation assays in S. typhimurium and E. coli, mammalian mutation assays in mouse lymphoma, chromosomal aberration assays in human peripheral blood lymphocytes, and the in vivo mouse bone marrow micronucleus assay.

Impairment of Fertility

The effects of Virenza on fertility and general reproductive performance were investigated in male (dosed for 10 weeks prior to mating, and throughout mating, gestation/lactation, and shortly after weaning) and female rats (dosed for 3 weeks prior to mating through Day 19 of pregnancy, or Day 21 post partum) at IV doses 1, 9, and 90 mg per kg per day. Virenza did not impair mating or fertility of male or female rats, and did not affect the sperm of treated male rats. The reproductive performance of the F1 generation born to female rats given Virenza was not affected. Based on a subchronic study in rats at a 90-mg-per-kg-per-day IV dose, AUC values ranged between 142 and 199 mcg-hour per mL (greater than 300 times the human exposure at the proposed clinical dose).

14 CLINICAL STUDIES

14.1 Treatment of Influenza

Adults and Adolescents

The efficacy of Virenza 10 mg inhaled twice daily for 5 days in the treatment of influenza has been evaluated in placebo-controlled trials conducted in North America, the Southern Hemisphere, and Europe during their respective influenza seasons. The magnitude of treatment effect varied between trials, with possible relationships to population-related factors including amount of symptomatic relief medication used.

Populations Studied: The principal Phase III trials enrolled 1,588 subjects aged 12 years and older, with uncomplicated influenza-like illness within 2 days of symptom onset. Influenza was confirmed by culture, hemagglutination inhibition antibodies, or investigational direct tests. Of 1,164 subjects with confirmed influenza, 89% had influenza A and 11% had influenza B. These trials served as the principal basis for efficacy evaluation, with more limited Phase II studies providing supporting information where necessary. Following randomization to either Virenza or placebo (inhaled lactose vehicle), all subjects received instruction and supervision by a healthcare professional for the initial dose.

Principal Results: The definition of time to improvement in major symptoms of influenza included no fever and self-assessment of “none” or “mild” for headache, myalgia, cough, and sore throat. A Phase II and a Phase III trial conducted in North America (total of over 600 influenza-positive subjects) suggested up to 1 day of shortening of median time to this defined improvement in symptoms in subjects receiving Virenza compared with placebo, although statistical significance was not reached in either of these trials. In a trial conducted in the Southern Hemisphere (321 influenza-positive subjects), a 1.5-day difference in median time to symptom improvement was observed. Additional evidence of efficacy was provided by the European trial.

Other Findings: There was no consistent difference in treatment effect in subjects with influenza A compared with influenza B; however, these trials enrolled smaller numbers of subjects with influenza B and thus provided less evidence in support of efficacy in influenza B.

In general, subjects with lower temperature (e.g., 38.2°C or less) or investigator-rated as having less severe symptoms at entry derived less benefit from therapy.

No consistent treatment effect was demonstrated in subjects with underlying chronic medical conditions, including respiratory or cardiovascular disease .

No consistent differences in rate of development of complications were observed between treatment groups.

Some fluctuation of symptoms was observed after the primary trial endpoint in both treatment groups.

Pediatric Patients

The efficacy of Virenza 10 mg inhaled twice daily for 5 days in the treatment of influenza in pediatric patients has been evaluated in a placebo-controlled trial conducted in North America and Europe, enrolling 471 subjects, aged 5 to 12 years (55% male, 90% Caucasian), within 36 hours of symptom onset. Of 346 subjects with confirmed influenza, 65% had influenza A and 35% had influenza B. The definition of time to improvement included no fever and parental assessment of no or mild cough and absent/minimal muscle and joint aches or pains, sore throat, chills/feverishness, and headache. Median time to symptom improvement was 1 day shorter in subjects receiving Virenza compared with placebo. No consistent differences in rate of development of complications were observed between treatment groups. Some fluctuation of symptoms was observed after the primary trial endpoint in both treatment groups.

Although this trial was designed to enroll children aged 5 to 12 years, the product is indicated only for children aged 7 years and older. This evaluation is based on the combination of lower estimates of treatment effect in 5- and 6-year-olds compared with the overall trial population, and evidence of inadequate inhalation through the DISKHALER in a pharmacokinetic trial .

14.2 Prophylaxis of Influenza

The efficacy of Virenza in preventing naturally occurring influenza illness has been demonstrated in 2 post-exposure prophylaxis trials in households and 2 seasonal prophylaxis trials during community outbreaks of influenza. The primary efficacy endpoint in these trials was the incidence of symptomatic, laboratory-confirmed influenza, defined as the presence of 2 or more of the following symptoms: oral temperature greater than or equal to 100°F/37.8°C or feverishness, cough, headache, sore throat, and myalgia; and laboratory confirmation of influenza A or B by culture, PCR, or seroconversion (defined as a 4-fold increase in convalescent antibody titer from baseline).

Household Prophylaxis Trials

Two trials assessed post-exposure prophylaxis in household contacts of an index case. Within 1.5 days of onset of symptoms in an index case, each household (including all family members aged 5 years and older) was randomized to Virenza 10 mg inhaled once daily or placebo inhaled once daily for 10 days. In the first trial only, each index case was randomized to Virenza 10 mg inhaled twice daily for 5 days or inhaled placebo twice daily for 5 days. In this trial, the proportion of households with at least 1 new case of symptomatic laboratory-confirmed influenza was reduced from 19.0% (32 of 168 households) for the placebo group to 4.1% (7 of 169 households) for the group receiving Virenza.

In the second trial, index cases were not treated. The incidence of symptomatic laboratory-confirmed influenza was reduced from 19.0% (46 of 242 households) for the placebo group to 4.1% (10 of 245 households) for the group receiving Virenza.

Seasonal Prophylaxis Trials

Two seasonal prophylaxis trials assessed Virenza 10 mg inhaled once daily versus placebo inhaled once daily for 28 days during community outbreaks. The first trial enrolled subjects aged 18 years or older (mean age: 29 years) from 2 university communities. The majority of subjects were unvaccinated (86%). In this trial, the incidence of symptomatic laboratory-confirmed influenza was reduced from 6.1% (34 of 554) for the placebo group to 2.0% (11 of 553) for the group receiving Virenza.

The second seasonal prophylaxis trial enrolled subjects aged 12 to 94 years (mean age 60 years) with 56% of them older than 65 years. Sixty-seven percent of the subjects were vaccinated. In this trial, the incidence of symptomatic laboratory-confirmed influenza was reduced from 1.4% (23 of 1,685) for the placebo group to 0.2% (4 of 1,678) for the group receiving Virenza.

16 HOW SUPPLIED/STORAGE AND HANDLING

Virenza is supplied in a circular double-foil pack (a ROTADISK) containing 4 blisters of the drug. Five ROTADISKs are packaged in a white polypropylene tube. The tube is packaged in a carton with 1 blue and gray DISKHALER inhalation device (NDC 0173-0681-01).

Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F). Keep out of reach of children. Do not puncture any Virenza ROTADISK blister until taking a dose using the DISKHALER.

17 PATIENT COUNSELING INFORMATION

Advise the patient to read the FDA-approved patient labeling (Patient Information and Instructions for Use).

Bronchospasm

Inform patients of the risk of bronchospasm, especially in the setting of underlying airways disease, and advise patients to stop Virenza and contact their healthcare provider if they experience increased respiratory symptoms during treatment such as worsening wheezing, shortness of breath, or other signs or symptoms of bronchospasm. If a decision is made to prescribe Virenza for a patient with asthma or chronic obstructive pulmonary disease, the patient should be made aware of the risks and should have a fast-acting bronchodilator available.

Concomitant Bronchodilator Use

Patients scheduled to take inhaled bronchodilators at the same time as Virenza should be advised to use their bronchodilators before taking Virenza.

Neuropsychiatric Events

Inform patients with influenza (the flu), particularly children and adolescents, they may be at an increased risk of seizures, confusion, or abnormal behavior early in their illness. These events may occur after beginning Virenza or may occur when flu is not treated. These events are uncommon but may result in accidental injury to the patient. Therefore, patients should be observed for signs of unusual behavior and a healthcare professional should be contacted immediately if the patient shows any signs of unusual behavior .

Instructions for Use

Instruct patients in use of the delivery system. Instructions should include a demonstration whenever possible. For the proper use of Virenza, the patient should read and follow carefully the accompanying Instructions for Use.

If Virenza is prescribed for children, it should be used only under adult supervision and instruction, and the supervising adult should first be instructed by a healthcare professional .

Risk of Influenza Transmission to Others

Inform patients that the use of Virenza for treatment of influenza has not been shown to reduce the risk of transmission of influenza to others.

Virenza, DISKHALER, and ROTADISK are registered trademarks of the GSK group of companies.

GlaxoSmithKline

Research Triangle Park, NC 27709

©2016 the GSK group of companies. All rights reserved.

RLZ:11PI

Patient Information

Virenza® (ruh-LENS-uh)

(zanamivir)

Inhalation Powder

This leaflet contains important patient information about Virenza (zanamivir) Inhalation Powder, and should be read completely before beginning treatment. It does not, however, take the place of discussions with your healthcare provider about your medical condition or your treatment. This summary does not list all benefits and risks of Virenza. The medication described here can only be prescribed and dispensed by a licensed healthcare provider, who has information about your medical condition and more information about the drug, including how to take it, what to expect, and potential side effects. If you have any questions about Virenza, talk with your healthcare provider.

What is Virenza?

Virenza is a medicine for the treatment of influenza (flu, infection caused by influenza virus) and for reducing the chance of getting the flu in community and household settings. It belongs to a group of medicines called neuraminidase inhibitors. These medications attack the influenza virus and prevent it from spreading inside your body. Virenza treats the cause of influenza at its source, rather than simply masking the symptoms.

Important Safety Information About Virenza

Some patients have had bronchospasm (wheezing) or serious breathing problems when they used Virenza. Many but not all of these patients had previous asthma or chronic obstructive pulmonary disease. Virenza has not been shown to shorten the duration of influenza in people with these diseases. Because of the risk of side effects and because it has not been shown to help them, Virenza is not recommended for people with chronic respiratory disease such as asthma or chronic obstructive pulmonary disease.

If you develop worsening respiratory symptoms such as wheezing or shortness of breath, stop using Virenza and contact your healthcare provider right away.

If you have chronic respiratory disease such as asthma and chronic obstructive pulmonary disease and your healthcare provider has prescribed Virenza, you should have a fast-acting, inhaled bronchodilator available for your use. If you are scheduled to use an inhaled bronchodilator at the same time as Virenza, use the inhaled bronchodilator before using Virenza.

Read the rest of this leaflet for more information about side effects and risks.

Other kinds of infections can appear like influenza or occur along with influenza, and need different kinds of treatment. Contact your healthcare provider if you feel worse or develop new symptoms during or after treatment, or if your influenza symptoms do not start to get better.

Who should not take Virenza?

Virenza is not recommended for people who have chronic lung disease such as asthma or chronic obstructive pulmonary disease. Virenza has not been shown to shorten the duration of influenza in people with these diseases, and some people have had serious side effects of bronchospasm and worsening lung function. (See the section of this Patient Information entitled “Important Safety Information About Virenza.”)

You should not take Virenza if you are allergic to Virenza or any other ingredient of Virenza. Also tell your healthcare provider if you have any type of chronic condition including lung or heart disease, if you are allergic to any other medicines, milk proteins or other food products, or if you are pregnant.

Virenza was not effective in reducing the chance of getting the flu in 2 studies in nursing home patients.

Virenza does not treat flu-like illness that is not caused by influenza virus.

Who should consider taking Virenza?

Adult and pediatric patients at least 7 years of age who have influenza symptoms that appeared within the previous day or two. Typical symptoms of influenza include sudden onset of fever, cough, headache, fatigue, muscular weakness, and sore throat.

Virenza can also help reduce the chance of getting the flu in adults and children at least 5 years of age who have a higher chance of getting the flu because they spend time with someone who has the flu. Virenza can also reduce the chance of getting the flu if there is a flu outbreak in the community.

The use of Virenza for the treatment of flu has not been shown to reduce the risk of spreading the virus to others.

Can I take other medications with Virenza?

Virenza has been shown to have an acceptable safety profile when used as labeled, with minimal risk of drug interactions. Your healthcare provider may recommend taking other medications, including over-the-counter medications, to reduce fever or other symptoms while you are taking Virenza. Before starting treatment, make sure that your healthcare provider knows if you are taking other medicines. If you are scheduled to use an inhaled bronchodilator at the same time as Virenza, you should use the inhaled bronchodilator before using Virenza.

Before taking Virenza, please let your healthcare provider know if you received live attenuated influenza vaccine (FLUMIST®) intranasal in the past 2 weeks.

How and when should I take Virenza?

Virenza is packaged in medicine disks called ROTADISKS® and is inhaled by mouth using a delivery device called a DISKHALER®. Each ROTADISK contains 4 blisters. Each blister contains 5 mg of active drug and 20 mg of lactose powder (which contains milk proteins).

You should receive a demonstration on how to use Virenza in the DISKHALER from a healthcare provider. Before taking Virenza, read the “Patient Instructions for Use.” Make sure that you understand these instructions and talk to your healthcare provider if you have any questions. Children who use Virenza should always be supervised by an adult who understands how to use Virenza. Proper use of the DISKHALER to inhale the drug is necessary for safe and effective use of Virenza.

If you have the flu the usual dose for treatment is 2 inhalations of Virenza (1 blister per inhalation) twice daily (in the morning and evening) for 5 days. It is important that you begin your treatment with Virenza as soon as possible from the first appearance of your flu symptoms. Take 2 doses on the first day of treatment whenever possible if there are at least 2 hours between doses.

To reduce the chance of getting the flu, the usual dose is 2 inhalations of Virenza (1 blister per inhalation) once daily for 10 or 28 days as prescribed by your healthcare provider.

Never share Virenza with anyone, even if they have the same symptoms. If you feel worse or develop new symptoms during treatment with Virenza, or if your flu symptoms do not start to get better, stop using the medicine and contact your healthcare provider.

What if I miss a dose?

If you forget to take your medicine at any time, take the missed dose as soon as you remember, except if it is near the next dose (within 2 hours). Then continue to take Virenza at the usual times. You do not need to take a double dose. If you have missed several doses, inform your healthcare provider and follow the advice given to you.

What are important or common possible side effects of taking Virenza?

Some patients have had breathing problems while taking Virenza. This can be very serious and need treatment right away. Most of the patients who had this problem had asthma or chronic obstructive pulmonary disease, but some did not. If you have trouble breathing or have wheezing after your dose of Virenza, stop taking Virenza and get medical attention.

In studies, the most common side effects with Virenza have been headaches; diarrhea; nausea; vomiting; nasal irritation; bronchitis; cough; sinusitis; ear, nose, and throat infections; and dizziness. Other side effects that have been reported, but were not as common, include rashes and allergic reactions, some of which were severe.

People with influenza (the flu), particularly children and adolescents, may be at an increased risk of seizures, confusion, or abnormal behavior early in their illness. These events may occur after beginning Virenza or may occur when flu is not treated. These events are uncommon but may result in accidental injury to the patient. Therefore, patients should be observed for signs of unusual behavior and a healthcare professional should be contacted immediately if the patient shows any signs of unusual behavior.

If you are not feeling well when you take Virenza, you may faint or become lightheaded after inhaling Virenza. You should sit down in a relaxed position before inhaling the dose of Virenza, and you should only hold your breath for as long as is comfortable after inhaling the dose.

If you are not feeling well, you are advised to have someone with you while you are inhaling the dose of Virenza.

This list of side effects is not complete. Your healthcare provider or pharmacist can discuss with you a more complete list of possible side effects with Virenza. Talk to your healthcare provider promptly about any side effects you have.

Call your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Please refer to the section entitled “Important Safety Information About RELENZA” for additional information.

Should I get a flu shot?

Virenza is not a substitute for a flu shot. You should receive an annual flu shot according to guidelines on immunization practices that your healthcare provider can share with you.

What if I am pregnant or nursing?

If you are pregnant or planning to become pregnant while taking Virenza, talk to your healthcare provider before taking this medication. Virenza is normally not recommended for use during pregnancy or nursing, as the effects on the unborn child or nursing infant are unknown.

How and where should I store Virenza?

Virenza should be stored at room temperature below 77°F (25°C). Virenza is not in a childproof container. Keep Virenza out of the reach of children. Discard the DISKHALER after finishing your treatment.

INSTRUCTIONS FOR USE

IMPORTANT: Read Step-by-Step Instructions before using the DISKHALER®.

Be sure to take the dose your healthcare provider has prescribed.

BEFORE YOU START:

Please read the entire Patient Information leaflet for important information about the effects of Virenza including the section “Important Safety Information About Virenza” for information about the risk of breathing difficulties.

If Virenza is prescribed for a child, dosing should be supervised by an adult who understands how to use Virenza and has been instructed in its use by a healthcare provider.

Step-by-step instructions for using the DISKHALER®

Step A: Load the medicine into the DISKHALER


Step B: Puncture the blister

Be sure to keep the DISKHALER level.

The DISKHALER punctures one blister of medicine at a time so you can inhale the right amount. It does not matter which blister you start with. Check to make sure that the silver foil is unbroken.


Step C: Inhale


To take another inhalation, move to the next blister by following Step D below.

Once you’ve inhaled the number of blisters prescribed by your healthcare provider, replace the cover until your next dose.

Step D: Move the medicine disk to the next blister


If all 4 blisters in the medicine disk have been used, you are ready to start a new medicine disk. Check to make sure that the silver foil is unbroken each time you are ready to puncture the next blister.



IMPORTANT INSTRUCTIONS

Read this entire leaflet before using Virenza. Even if you have had a previous prescription for Virenza, read this leaflet to see if any information has changed.

If you have the flu, the usual dose is 2 inhalations twice daily. To reduce the chance of getting the flu, the usual dose is 2 inhalations once daily. However, you must take the number of inhalations your healthcare provider has prescribed.

If you feel worse or develop new symptoms during or after treatment, or if your flu symptoms do not start to improve, stop using the medicine and contact your healthcare provider.

Keep out of reach of children.

Always check inside the mouthpiece to make sure it is clear before each use. If foreign objects are in the mouthpiece, they could be inhaled and cause serious harm.

Always replace the cover after each use.

Throw away the DISKHALER after treatment is completed.

This DISKHALER is for use only with Virenza. Do not use the Virenza DISKHALER device with FLOVENT® (fluticasone propionate) and do not use Virenza with the FLOVENT DISKHALER device.

Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F).

REMEMBER: This medicine has been prescribed for you by your healthcare provider. DO NOT give this medicine to anyone else.

Virenza, FLOVENT, ROTADISK, and DISKHALER are registered trademarks of the GSK group of companies.

FLUMIST is a registered trademark of MedImmune, Inc.

GlaxoSmithKline

Research Triangle Park, NC 27709

©2016 the GSK group of companies. All rights reserved.

August 2016

RLZ:7PIL

Virenza logo Parts of the DISKHALER Step A: Load the medicine in DISKHALER Step B: Steps 1, 2, 3, and 4 Step C: Steps 1 and 2 Step D: Steps 1 and 2

Virenza pharmaceutical active ingredients containing related brand and generic drugs:


Virenza available forms, composition, doses:


Virenza destination | category:


Virenza Anatomical Therapeutic Chemical codes:


Virenza pharmaceutical companies:


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References

  1. Dailymed."RELENZA (ZANAMIVIR) POWDER [GLAXOSMITHKLINE LLC]". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  2. Dailymed."ZANAMIVIR: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailym... (accessed August 28, 2018).
  3. "zanamivir". https://pubchem.ncbi.nlm.nih.gov/co... (accessed August 28, 2018).

Frequently asked Questions

Can i drive or operate heavy machine after consuming Virenza?

Depending on the reaction of the Virenza after taken, if you are feeling dizziness, drowsiness or any weakness as a reaction on your body, Then consider Virenza not safe to drive or operate heavy machine after consumption. Meaning that, do not drive or operate heavy duty machines after taking the capsule if the capsule has a strange reaction on your body like dizziness, drowsiness. As prescribed by a pharmacist, it is dangerous to take alcohol while taking medicines as it exposed patients to drowsiness and health risk. Please take note of such effect most especially when taking Primosa capsule. It's advisable to consult your doctor on time for a proper recommendation and medical consultations.

Is Virenza addictive or habit forming?

Medicines are not designed with the mind of creating an addiction or abuse on the health of the users. Addictive Medicine is categorically called Controlled substances by the government. For instance, Schedule H or X in India and schedule II-V in the US are controlled substances.

Please consult the medicine instruction manual on how to use and ensure it is not a controlled substance.In conclusion, self medication is a killer to your health. Consult your doctor for a proper prescription, recommendation, and guidiance.

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Review

sdrugs.com conducted a study on Virenza, and the result of the survey is set out below. It is noteworthy that the product of the survey is based on the perception and impressions of the visitors of the website as well as the views of Virenza consumers. We, as a result of this, advice that you do not base your therapeutic or medical decisions on this result, but rather consult your certified medical experts for their recommendations.

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The information was verified by Dr. Rachana Salvi, MD Pharmacology


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