SELZENTRY (maraviroc) is a selective, slowly reversible, small molecule antagonist of the interaction between human CCR5 and HIV-1 gp120. Blocking this interaction prevents CCR5-tropic HIV-1 entry into cells.

SELZENTRY is available as film-coated tablets for oral administration containing either 150 or 300 mg of maraviroc and the following inactive ingredients: microcrystalline cellulose, dibasic calcium phosphate (anhydrous), sodium starch glycolate, and magnesium stearate. The film coat [Opadry®II Blue (85G20583)] contains FD&C blue #2 aluminum lake, soya lecithin, polyethylene glycol (macrogol 3350), polyvinyl alcohol, talc and titanium dioxide.

Maraviroc is chemically described as 4,4-difluoro-N-{(1S)-3-[exo-3-(3-isopropyl-5-methyl-4H-1,2,4- triazol-4-yl)-8-azabicyclo[3.2.1]oct-8-yl]-1-phenylpropyl}cyclohexanecarboxamide.

The molecular formula is C₂₉H₄₁F₂N₅O and the structural formula is:

Maraviroc is a white to pale colored powder with a molecular weight of 513.67. It is highly soluble across the physiological pH range (pH 1.0 to 7.5).

Last updated on RxList: 2/11/2009

SELZENTRY, in combination with other antiretroviral agents, is indicated for treatment-experienced adult patients infected with only CCR5-tropic HIV-1, who have evidence of viral replication and HIV-1 strains resistant to multiple antiretroviral agents.

This indication is based on analyses of plasma HIV-1 RNA levels in two controlled studies of SELZENTRY of 48 weeks duration. Both studies were conducted in clinically advanced, 3-class antiretroviral (NRTI, NNRTI, PI, or enfuvirtide) treatment-experienced adults with evidence of HIV-1 replication despite ongoing antiretroviral therapy.

The following points should be considered when initiating therapy with SELZENTRY:

• Tropism testing is required for the appropriate use of SELZENTRY.
• Use of SELZENTRY is not recommended in patients with dual/mixed or CXCR4-tropic HIV-1 as efficacy was not demonstrated in a phase 2 study of this patient group.
• The safety and efficacy of SELZENTRY have not been established in treatment-naïve adult patients or pediatric patients.

The recommended dose of SELZENTRY differs based on concomitant medications due to drug interactions (see Table 1). SELZENTRY can be taken with or without food. SELZENTRY must be given in combination with other antiretroviral medications.

Table 1 gives the recommended dose adjustments [see DRUG INTERACTIONS].

Table 1 Recommended Dosing Regimen

Concomitant Medications	SELZENTRY Dose
Potent CYP3A inhibitors (with or without a CYP3A inducer) including: protease inhibitors (except tipranavir/ritonavir) delavirdine ketoconazole, itraconazole, clarithromycin other potent CYP3A inhibitors (e.g., nefazodone, telithromycin)	150 mg twice daily
Other concomitant medications, including tipranavir/ritonavir, nevirapine, all NRTIs and enfuvirtide	300 mg twice daily
Potent CYP3A inducers (without a potent CYP3A inhibitor) including: efavirenz rifampin carbamazepine, phenobarbital, and phenytoin	600 mg twice daily

Dosage Forms And Strengths

• 150 mg blue, oval film-coated tablets debossed with “Pfizer” on one side and “MVC 150” on the other
• 300 mg blue, oval film-coated tablets debossed with “Pfizer” on one side and “MVC 300” on the other

Storage And Handling

SELZENTRY film-coated tablets are available as follows:

150 and 300 mg tablets are blue, biconvex, oval film-coated tablets debossed with “Pfizer” on one side and “MVC 150” or “MVC 300” on the other.

Bottle packs 150 mg tablets

60 tablets (NDC 0069-0807-60)

Bottle packs 300 mg tablets

60 tablets (NDC 0069-0808-60)

SELZENTRY film-coated tablets should be stored at 25°C (77°F); excursions permitted between 15°and 30°C (59°-86°F) [see USP Controlled Room Temperature].

Shelf life is 24 months.

Issued November 2008. Distributed by : Pfizer Labs, Division of Pfizer Inc, NY, NY 10017. FDA rev date: 11/25/2008

Last updated on RxList: 2/11/2009

The following adverse reactions are discussed in other sections of the labeling:

• Hepatotoxicity [see BOXED WARNING, WARNINGS AND PRECAUTIONS]
• Cardiovascular events [see WARNINGS AND PRECAUTIONS ]

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 to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety profile of SELZENTRY is primarily based on 840 HIV-infected subjects who received at least one dose of SELZENTRY during two Phase 3 trials. A total of 426 of these subjects received the indicated twice daily dosing regimen.

Assessment of treatment-emergent adverse events is based on the pooled data from two studies in subjects with CCR5-tropic HIV-1 (A4001027 and A4001028). The median duration of maraviroc therapy for subjects in these studies was 48 weeks, with the total exposure on SELZENTRY twice daily at 309 patient-years versus 111 patient-years on placebo + OBT. The population was 89% male and 84% white, with mean age of 46 years (range 17-75 years). Subjects received dose equivalents of 300 mg maraviroc once or twice daily.

The most common adverse events reported with SELZENTRY twice daily therapy with frequency rates higher than placebo, regardless of causality, were upper respiratory tract infections, cough, pyrexia, rash, and dizziness. Additional adverse events that occurred with once daily dosing at a higher rate than both placebo and twice daily dosing were diarrhea, edema, influenza, esophageal candidiasis, sleep disorders, rhinitis, parasomnias, and urinary abnormalities. In these two studies, the rate of discontinuation due to adverse events was 5% for subjects who received SELZENTRY twice daily + optimized background therapy (OBT) as well as those who received placebo + OBT. Most of the adverse events reported were judged to be mild to moderate in severity. The data described below occurred with SELZENTRY twice daily dosing.

The total number of subjects reporting infections were 233 (55%) and 84 (40%) in the SELZENTRY twice daily and placebo groups, respectively. Correcting for the longer duration of exposure on SELZENTRY compared to placebo, the exposure-adjusted frequency (rate per 100 subject-years) of these events was 133 for both SELZENTRY twice daily and placebo.

Dizziness or postural dizziness occurred in 8% of subjects on either SELZENTRY and placebo, with 2 subjects (0.5%) on SELZENTRY permanently discontinuing therapy (1 due to syncope, 1 due to orthostatic hypotension) versus 1 subject on placebo (0.5%) permanently discontinuing therapy due to dizziness.

Treatment-emergent adverse events, regardless of causality, from A4001027 and A4001028 are summarized in Table 2. Selected events occurring at ¡Ý2% of subjects and at a numerically higher rate in subjects treated with SELZENTRY are included; events that occurred at the same or higher rate onplacebo are not displayed.

Table 2 : Percentage of Subjects with Selected Treatment-Emergent Adverse Events (All Causality) ( ≥ 2% on SELZENTRY and at a higher rate compared to placebo) Studies A4001027 and A4001028 (Pooled Analysis, 48 Weeks)

	SELZENTRY Twice Daily*	Exposure adjusted rate (per 100 pt-yrs) PYE=309**	Placebo	Exposure adjusted rate (per 100 pt-yrs) PYE=111**
	N=426 (%)		N=209 (%)
EYE DISORDERS
Conjunctivitis	2	3	1	3
Ocular infections, inflammations and associated manifestations	2	3	1	2
GASTROINTESTINAL DISORDERS
Constipation	6	9	3	6
GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS
Pyrexia	13	20	9	17
Pain and discomfort	4	5	3	5
INFECTIONS AND INFESTATIONS
Upper respiratory tract infection	23	37	13	27
Herpes Infection	8	11	4	8
Sinusitis	7	10	3	6
Bronchitis	7	9	5	9
Folliculitis	4	5	2	4
Pneumonia	2	3	5	10
Anogenital warts	2	3	1	3
Influenza	2	3	0.5	1
Otitis media	2	3	0.5	1
METABOLISM AND NUTRITION DISORDERS
Appetite disorders	8	11	7	13
MUSCULOSKELETAL AND CONNECTIVE TISSUE
DISORDERS
Joint related signs and symptoms	7	10	3	5
Muscle pains	3	4	0.5	1
NEOPLASMS BENIGN, MALIGNANT AND UNSPECIFIED
Skin neoplasms benign	3	4	1	3
NERVOUS SYSTEM DISORDERS
Dizziness/postural dizziness	9	13	8	17
Paresthesias and dysesthesias	5	7	3	6
Sensory abnormalit ies	4	6	1	3
Disturbances in consciousness	4	5	3	6
Peripheral neuropathies	4	5	3	6
PSYCHIATRIC DISORDERS
Disturbances in initiating and maintaining sleep	8	11	5	10
Depressive disorders	4	6	3	5
Anxiety symptoms	4	5	3	7
RENAL AND URINARY DISORDERS
Bladder and urethral symptoms	5	7	1	3
Urinary tract signs and symptoms	3	4	1	3
RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS
Coughing and associated symp toms	14	21	5	10
Upper respiratory tractsigns and symptoms	6	9	3	6
Nasal congestion and inflammations	4	6	3	5
Breathing abnormalities	4	5	2	5
Paranasal sinus disorders	3	4	0.5	1
SKIN AND SUBCUTANEOUS TISSUE DISORDERS
Rash	11	16	5	11
Apocrine and eccrine gland disorders	5	7	4	7.5
Pruritus	4	5	2	4
Lipodystrophies	3	5	0.5	1
Erythemas	2	3	1	2
VASCULAR DISORDERS
Vascular hypertensive disorders	3	4	2	4
* 300 mg dose equivalent ** PYE = patient years of exposure

Less Common Adverse Events

The following adverse events occurred in < 2% of SELZENTRY-treated patients. These events have been included because of their seriousness and either increased frequency on SELZENTRY or are potential risks due to the mechanism of action. Events attributed to the patient's underlying HIV infection are not listed.

Blood and Lymphatic System:Marrow depression and hypoplastic anemia

Cardiac Disorders: unstable angina, acute cardiac failure, coronary artery disease, coronary artery occlusion, myocardial infarction, myocardial ischemia

Hepatobiliary Disorders:hepatic cirrhosis, hepatic failure, cholestatic jaundice, portal vein thrombosis

Infections and Infestations: endocarditis, infective myositis, viral meningitis, pneumonia, treponema infections, septic shock

Musculoskeletal and Connective Tissue Disorders: myositis, osteonecrosis, rhabdomyolysis, blood CK increased

Neoplasms benign, malignant and Unspecified (incl Cysts and Polyps): anal cancer, anaplastic large cell lymphomas T- and null-cell types, bile duct neoplasms malignant, endocrine neoplasms malignant and unspecified, basal cell carcinoma, lymphoma, metastases to liver, esophageal carcinoma, squamous cell carcinoma, tongue neoplasm (malignant stage unspecified)

Nervous System Disorders: cerebrovascular accident, convulsions and epilepsy, tremor (excluding congenital)

Laboratory Abnormalities

Table 3 shows the treatment-emergent Grade 3-4 laboratory abnormalities that occurred in > 2% of patients receiving SELZENTRY.

Table 3 : Maximum Shift in Laboratory Test Values (Without Regard to Baseline) Incidence ≥ 2% of Grade 3-4 Abnormalities (ACTG Criteria) Studies A4001027 and A4001028 (Pooled Analysis, 48 Weeks)

Laboratory Parameter Preferred Term, %	Limit	SELZENTRY Twice daily+ OBT N =421*%	Placebo + OBT N =207*%
Aspartate aminotransferase	> 5.0x ULN	4.8	2.9
Alanine aminotransferase	> 5.0x ULN	2.6	3.4
Total bilirubin	> 5.0x ULN	5.5	5.3
Am ylase	> 2.0x ULN	5.7	5.8
Lipase	> 2.0x ULN	4.9	6.3
Absolute neutrophil count	< 750/mm³	4.3	2.4
* Percentages based on total patients evaluated for each laboratory parameter

Effect of Concomitant Drugs on the Pharmacokinetics of Maraviroc

Maraviroc is a substrate of CYP3A and Pgp and hence its pharmacokinetics are likely to be modulated by inhibitors and inducers of these enzymes/transporters. Therefore, a dose adjustment may be required when maraviroc is coadministered with those drugs [see DOSAGE AND ADMINISTRATION].

Concomitant use of maraviroc and St. John's wort (hypericum perforatum) or products containing St. John's wort is not recommended. Coadministration of maraviroc with St. John's wort is expected to substantially decrease maraviroc concentrations and may result in suboptimal levels of maraviroc and lead to loss of virologic response and possible resistance to maraviroc.

For additional drug interaction information see CLINICAL PHARMACOLOGY.

Last updated on RxList: 2/11/2009

Included as part of the PRECAUTIONS section.

Hepatotoxicity

A case of possible SELZENTRY-induced hepatotoxicity with allergic features has been reported in a study of healthy volunteers. In addition, an increase in hepatic adverse events with SELZENTRY was observed during studies of treatment-experienced subjects with HIV infection, although there was no overall increase in ACTG Grade 3/4 liver function test abnormalities [see ADVERSE REACTIONS]. Discontinuation of SELZENTRY should be considered in any patient with signs or symptoms of hepatitis, or with increased liver transaminases combined with rash or other systemic symptoms.

The safety and efficacy of SELZENTRY have not been specifically studied in patients with significant underlying liver disorders. In studies of treatment-experienced HIV-infected subjects, approximately 6% of subjects were co-infected with hepatitis B and approximately 6% were co-infected with hepatitis C. Due to the small number of co-infected subjects studied, no conclusions can be drawn regarding whether they are at an increased risk for hepatic adverse events with SELZENTRY administration. However, caution should be used when administering SELZENTRY to patients with preexisting liver dysfunction or who are co-infected with viral hepatitis B or C.

Cardiovascular Events

Use with caution in patients at increased risk for cardiovascular events. Eleven subjects (1.3%) who received SELZENTRY had cardiovascular events including myocardial ischemia and/or infarction during the Phase 3 studies [total exposure 609 patient-years (300 on once daily + 309 on twice daily SELZENTRY)], while no subjects who received placebo had such events (total exposure 111 patientyears). These subjects generally had cardiac disease or cardiac risk factors prior to SELZENTRY use, and the relative contribution of SELZENTRY to these events is not known.

When SELZENTRY was administered to healthy volunteers at doses higher than the recommended dose, symptomatic postural hypotension was seen at a greater frequency than in placebo. However, when SELZENTRY was given at the recommended dose in HIV subjects in Phase 3 studies, postural hypotension was seen at a rate similar to placebo (approximately 0.5%). Caution should be used when administering SELZENTRY in patients with a history of postural hypotension or on concomitant medication known to lower blood pressure.

Immune Reconstitution Syndrome

Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including maraviroc. During the initial phase of combination antiretroviral treatment, patients whose immune system responds may develop an inflammatory response to indolent or residual opportunistic infections (such as infection with Mycobacterium avium, cytomegalovirus, Pneumocystis jirovecii, Mycobacterium tuberculosis, or reactivation of Herpes simplex and Herpes zoster), which may necessitate further evaluation and treatment.

Potential Risk of Infection

SELZENTRY antagonizes the CCR5 co-receptor located on some immune cells, and therefore could potentially increase the risk of developing infections. The overall incidence and severity of infection, as well as AIDS-defining category C infections, was comparable in the treatment groups during the Phase 3 studies of SELZENTRY. While there was a higher rate of certain upper respiratory tract infections reported in the SELZENTRY arm compared to placebo (23% versus 13%), there was a lower rate of pneumonia (2% vs 5%) reported in patients receiving SELZENTRY. A higher incidence of Herpes virus infections (11 per 100 patient-years) was also reported in the SELZENTRY arm when adjusted for exposure compared to placebo (8 per 100 patient-years). Patients should be monitored closely for evidence of infections while receiving SELZENTRY.

Potential Risk of Malignancy

While no increase in malignancy has been observed with SELZENTRY, due to this drug's mechanism of action it could affect immune surveillance and lead to an increased risk of malignancy. Long-term follow-up is needed to more fully assess this risk.

Patient Counseling Information

See Medication Guide.

Patients should be informed that if they develop signs or symptoms of hepatitis or allergic reaction following use of SELZENTRY (rash, skin or eyes look yellow, dark urine, vomiting, abdominal pain), they should stop SELZENTRY and seek medical evaluation immediately [see WARNINGS AND PRECAUTIONS].

Patients should be informed that SELZENTRY is not a cure for HIV infection and patients may still develop illnesses associated with HIV infection, including opportunistic infections. The use of SELZENTRY has not been shown to reduce the risk of transmission of HIV to others through sexual contact, sharing needles or blood contamination.

Patients should be advised that it is important to:

• remain under the care of a physician when using SELZENTRY;
• take SELZENTRY every day as prescribed and in combination with other antiretroviral drugs;
• report to their physician the use of any other prescription or nonprescription medication or herbal products;
• inform their physician if they are pregnant, plan to become pregnant or become pregnant while taking SELZENTRY;
• not change the dose or dosing schedule of SELZENTRY or any antiretroviral medication without consulting their physician.

Patients should be advised that if they forget to take a dose, they should take the next dose of SELZENTRY as soon as possible and then take their next scheduled dose at its regular time. If it is less than 6 hours before their next scheduled dose, they should not take the missed dose and should instead wait and take the next dose at the regular time.

Caution should be used when administering SELZENTRY in patients with a history of postural hypotension or on concomitant medication known to lower blood pressure. Patients should be advised that if they experience dizziness while taking SELZENTRY, they should avoid driving or operating machinery.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

Long-term oral carcinogenicity studies of maraviroc were carried out in rasH2 transgenic mice (6 months) and in rats for up to 96 weeks (females) and 104 weeks (males). No drug-related increases in tumor incidence were found in mice at 1500 mg/kg/day and in male and female rats at 900 mg/kg/day. The highest exposures in rats were approximately 11 times those observed in humans at the therapeutic dose of 300 mg twice daily for the treatment of HIV-1 infection.

Mutagenesis

Maraviroc was not genotoxic in the reverse mutation bacterial test (Ames test in Salmonella and E. coli), a chromosome aberration test in human lymphocytes and rat bone marrow micronucleus test.

Impairment of Fertility

Maraviroc did not impair mating or fertility of male or female rats and did not affect sperm of treated male rats at approximately 20-fold higher exposures (AUC) than in humans given the recommended 300 mg twice daily dose.

Use In Specific Populations

Pregnancy

Pregnancy Category B

The incidence of fetal variations and malformations was not increased in embryofetal toxicity studies performed with maraviroc in rats at exposures (AUC) approximately 20-fold higher and in rabbits at approximately 5-fold higher than human exposures at the recommended daily dose (up to 1000 mg/kg/day in rats and 75 mg/kg/day in rabbits). During the pre- and post-natal development studies in the offspring, development of the offspring, including fertility and reproductive performance, was not affected by thematernal administration of maraviroc.

However, there are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, SELZENTRY should be used during pregnancy only if clearly needed.

Antiretroviral Pregnancy Registry

To monitor maternal-fetal outcomes of pregnant women exposed to SELZENTRY and other antiretroviral agents, an Antiretroviral Pregnancy Registry has been established. Physicians are encouraged to register patients by calling 1-800-258-4263.

Nursing Mothers

The Centers for Disease Control and Prevention recommend that HIV-infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV infection. Studies in lactating rats indicate that maraviroc is extensively secreted into rat milk. It is not known whether maraviroc is secreted into human milk. Because of the potential for both HIV transmission and serious adverse reactions in nursing infants, mothers should be instructed not to breastfeed if they are receiving SELZENTRY.

Pediatric Use

The pharmacokinetics, safety and efficacy of maraviroc in patients < 16 years of age have not been established. Therefore, maraviroc should not be used in this patient population.

Geriatric Use

There were insufficient numbers of subjects aged 65 and over in the clinical studies to determine whether they respond differently from younger subjects. In general, caution should be exercised when administering SELZENTRY in elderly patients, also reflecting the greater frequency of decreased hepatic and renal function, of concomitant disease and other drug therapy.

Renal Impairment

The safety and efficacy of maraviroc have not been specifically studied in patients with renal impairment, therefore maraviroc should be used with caution in this population. In the absence of metabolic inhibitors, renal clearance accounts for approximately 23% of total clearance of maraviroc. Maraviroc concentrations may be increased in patients with renal impairment, especially when CYP3A inhibitors are coadministered. Patients with a creatinine clearance of less than 50 mL/min who receive maraviroc and a CYP3A inhibitor may be at an increased risk of adverse effects related to increased maraviroc concentrations, such as dizziness and postural hypotension. Thus, patients with a creatinine clearance of less than 50 mL/min should receive maraviroc and a CYP3A inhibitor only if the potential benefit is felt to outweigh the risk, and they should be monitored for adverse effects.

Hepatic Impairment

Maraviroc is principally metabolized by the liver; therefore, caution should be exercised when administering this drug to patients with hepatic impairment, because maraviroc concentrations may be increased. Maraviroc has not been studied in subjects with severe hepatic impairment. [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Gender

Population pharmacokinetic analysis of pooled Phase 1/2a data indicated gender (female: n=96, 23.2% of the total population) does not affect maraviroc concentrations. Dosage adjustment based on gender is not necessary.

Race

Population pharmacokinetic analysis of pooled Phase 1/2a data indicated exposure was 26.5% higher in Asians (N=95) as compared to non-Asians (n=318). However, a study designed to evaluate pharmacokinetic differences between Caucasians (n=12) and Singaporeans (n=12) showed no difference between these two populations. Only 14 Black subjects were included in the population pharmacokinetic analysis. No dosage adjustment based on race is needed.

Last updated on RxList: 2/11/2009

The highest dose administered in clinical studies was 1200 mg. The dose-limiting adverse event was postural hypotension, which was observed at 600 mg. While the recommended dose for SELZENTRY in patients receiving a CYP3A inducer without a CYP3A inhibitor is 600 mg twice daily, this dose is appropriate due to enhanced metabolism.

Prolongation of the QT interval was seen in dogs and monkeys at plasma concentrations 6 and 12 times, respectively, those expected in humans at the intended exposure of 300 mg equivalents twice daily. However, no significant QT prolongation was seen in the studies in treatment-experienced patientswith HIV using the recommended doses of maraviroc or in a specific pharmacokinetic study to evaluate the potential of maraviroc to prolong the QT interval [see CLINICAL PHARMACOLOGY].

There is no specific antidote for overdose with maraviroc. Treatment of overdose should consist of general supportive measures including keeping the patient in a supine position, careful assessment of patient vital signs, blood pressure and ECG.

If indicated, elimination of unabsorbed active maraviroc should be achieved by emesis or gastric lavage. Administration of activated charcoal may also be used to aid in removal of unabsorbed drug. Since maraviroc is moderately protein-bound, dialysis may be beneficial in removal of this medicine.

None

Last updated on RxList: 2/11/2009

Mechanism of Action

Maraviroc is an antiviral drug.

Pharmacodynamics

Exposure Response Relationship

The relationship between maraviroc mean predicted plasma trough concentration (Cmin) (1-9 samples per patient taken on up to 7 visits) and virologic response was evaluated in 973 treatment-experienced HIV-1-infected subjects in studies A4001027 and A4001028. The Cmin, baseline viral load, baseline CD4+ cell count and overall sensitivity score (OSS) were found to be important predictors of virologic success (defined as viral load < 400 copies/mL at 24 weeks). Table 4 illustrates the proportion of patients with virologic success (%) within each Cmin quartile for 150 mg twice daily and 300 mg twice daily groups.

Table 4 : Patients with Virologic Success by Cmin Quartile

	150 mg BID (with CYP3A inhibitors)			300 mg BID (without CYP3A inhibitors)
	n	Median Cmin	% patients with virologic success	n	Median Cmin	% patients with virologic success
Placebo	160	-	30.6	35	-	28.6
Q1	78	33	52.6	22	13	50.0
Q2	77	87	63.6	22	29	68.2
Q3	78	166	78.2	22	46	63.6
Q4	78	279	74.4	22	97	68.2

Effects on Electrocardiogram

A placebo-controlled, randomized, crossover study to evaluate the effect on the QT interval of healthy male and female volunteers was conducted with three single oral doses of maraviroc and moxifloxacin. The placebo-adjusted mean maximum (upper 1-sided 95% CI) increases in QTc from baseline after 100, 300 and 900 mg of maraviroc were –2 (0), -1 (1), and 1 (3) msec, respectively, and 13 (15) msec for moxifloxacin 400 mg. No subject in any group had an increase in QTc of ≥ 60 msec from baseline. No subject experienced an interval exceeding the potentially clinically relevant threshold of 500 msec.

Pharmacokinetics

Table 5 : Mean Maraviroc Pharmacokinetic Parameters

	Maraviroc dose	N	AUC12 (ng•h/m)	Cmax (ng/mL)	Cmin (ng/mL)
Healthy volunteers (phase 1)	300 mg twice daily	64	2908	888	43.1
As ymptomatic HIV patients (phase 2a)	300 mg twice daily	8	2550	618	33.6
Trea tment -experienced HIV patients (phase 3)*	300 mg twice daily	94	1513	266	37.2
	150 mg twice daily (+ CYP3A inhibitor)	375	2463	332	101
* The estimated exposure is lower compared to other studies possibly due to food effect, compliance and concomitant medications.

Absorption

Peak maraviroc plasma concentrations are attained 0.5-4h following single oral doses of 1-1200 mg administered to uninfected volunteers. The pharmacokinetics of oral maraviroc are not dose-proportional over the dose range.

The absolute bioavailability of a 100 mg dose is 23% and is predicted to be 33% at 300 mg. Maraviroc is a substrate for the efflux transporter P-glycoprotein.

Effect of Food on Oral Absorption

Coadministration of a 300mg tablet with a high fat breakfast reduced maraviroc Cmax and AUC by 33% in healthy volunteers. There were no food restrictions in the studies that demonstrated the efficacy and safety of maraviroc [see Clinical Studies]. Therefore, maraviroc can be taken with or without food at the recommended dose [see DOSAGE AND ADMINISTRATION].

Distribution

Maraviroc is bound (approximately 76%) to human plasma proteins, and shows moderate affinity for albumin and alpha-1 acid glycoprotein. The volume of distribution of maraviroc is approximately 194L.

Metabolism

Studies in humans and in vitro studies using human liver microsomes and expressed enzymes have demonstrated that maraviroc is principally metabolized by the cytochrome P450 system to metabolites that are essentially inactive against HIV-1. In vitro studies indicate that CYP3A is the major enzyme responsible for maraviroc metabolism. In vitro studies also indicate that polymorphic enzymes CYP2C9, CYP2D6 and CYP2C19 do not contribute significantly to the metabolism of maraviroc.

Maraviroc is the major circulating component (~42% drug-related radioactivity) following a single oral dose of 300 mg[14C]-maraviroc. The most significant circulating metabolite in humans is a secondary amine (~22% radioactivity) formed by N-dealkylation. This polar metabolite has no significant pharmacological activity. Other metabolites are products of mono-oxidation and are only minor components of plasma drug-related radioactivity.

Excretion

The terminal half-life of maraviroc following oral dosing to steady-state in healthy subjects was 14- 18 hours. A mass balance/excretion study was conducted using a single 300mg dose of 14C-labeled maraviroc. Approximately 20% of the radiolabel was recovered in the urine and 76% was recovered in the feces over 168 hours. Maraviroc was the major component present in urine (mean of 8% dose) and feces (mean of 25% dose). The remainder was excreted as metabolites.

Hepatic Impairment

Maraviroc is primarily metabolized and eliminated by the liver. A study compared the pharmacokinetics of a single 300 mg dose of SELZENTRY in patients with mild (Child-Pugh Class A, n=8), and moderate (Child-Pugh Class B, n=8) hepatic impairment to pharmacokinetics in healthy subjects (n=8). The mean Cmax and AUC were 11% and 25% higher, respectively, for subjects with mild hepatic impairment, and 32% and 46% higher, respectively, for subjects with moderate hepatic impairment compared to subjects with normal hepatic function. These changes do not warrant a dose adjustment. Maraviroc concentrations are higher when SELZENTRY 150 mg is administered with a strong CYP3A inhibitor compared to following administration of 300 mg without a CYP3A inhibitor, so patients with moderate hepatic impairment who receive SELZENTRY 150 mg with a strong CYP3A inhibitor should be monitored closely for maraviroc associated adverse events. The pharmacokinetics of maraviroc have not been studied in subjects with severe hepatic impairment. [see WARNINGS AND PRECAUTIONS]

Effect of Concomitant Drugs on the Pharmacokinetics of Maraviroc

Maraviroc is a substrate of CYP3A and Pgp and hence its pharmacokinetics are likely to be modulated by inhibitors and inducers of these enzymes/transporters. The CYP3A/Pgp inhibitors ketoconazole, lopinavir/ritonavir, ritonavir, saquinavir and atazanavir all increased the Cmax and AUC of maraviroc [see Table 6]. The CYP3A inducers rifampin and efavirenz decreased the Cmax and AUC of maraviroc [see Table 6].

Tipranavir/ritonavir (net CYP3A inhibitor/Pgp inducer) did not affect the steady state pharmacokinetics of maraviroc. Co-trimoxazole and tenofovir did not affect the pharmacokinetics of maraviroc (see Table 6).

Table 6 : Effect of Co-administered Agents on the Pharmacokinetics of Maraviroc

Co-administered drug and dose	N	Maraviroc Dose	Ratio (90% CI) of maraviroc pharmacokinetic parameters with/without co-administered drug (no effect = 1.00)
			Cmin	AUCtau	Cmax
CYP3A and/or P-gp Inhibitors Ketoconazole 400 mg QD	12	100 mg BID	3.75 (3.01-4.69)	5.00 (3.98, 6.29)	3.38 (2.38, 4.78)
Ritonavir 100 mg BID	8	100 mg BID	4.55 (3.37-6.13)	2.61 (1.92, 3.56)	1.28 (0.79, 2.09)
Saquinavir (soft gel capsules) /ritonavir 1000 mg/100 mg BID	11	100 mg BID	11.3 (8.96-14.1)	9.77 (7.87, 12.14)	4.78 (3.41, 6.71)
Lopinavir/ritonavir 400 mg/100 mg BID	11	300 mg BID	9.24 (7.98-10.7)	3.95 (3.43, 4.56)	1.97 (1.66, 2.34)
Atazanavir 400 mg QD	12	300 mg BID	4.19 (3.65-4.80)	3.57 (3.30, 3.87)	2.09 (1.72, 2.55)
Darunavir/ritonavir 600 mg/100 mg BID	12	150 mg BID	8.00 (6.35, 10.1)	4.05 2.94, 5.59	2.29 (1.46, 3.59)
CYP3A and/or P-gp Inducers
Efavirenz 600 mg QD	12	100 mg BID	0.55 (0.43-0.72)	0.552 (0.492, 0.620)	0.486 (0.377, 0.626)
Rifampicin 600 mg QD		100 mg BID	0.22 (0.17-0.28)	0.368 (0.328, 0.413)	0.335 (0.260, 0.431)
Nevirapine* 200 mg BID (+ lamivudine 150 mg BID, tenofovir 300 mg QD)	8	300 mg BID	-	1.01 (0.65, 1.55)	1.54 (0.94, 2.51)
CYP3A and/or P-gp Inhibitors and Inducers
Lopinavir/ritonavir + efavirenz 400 mg/100 mg BID + 600 mg QD	11	300 mg BID	6.29 4.72-8.39)	2.53 (2.24, 2.87)	1.25 1.01, 1.55)
Saquinavir(soft gel capsules) /ritonavir + efavirenz 1000 mg/100 mg BID + 600 mg QD	11	100 mg BID	8.42 (6.46-10.97)	5.00 (4.26, 5.87)	2.26 (1.64, 3.11)
Tipranavir/ritonavir 500 mg/200 mg BID	12	150 mg BID	1.80 (1.55-2.09)	1.02 (0.850, 1.23)	0.86 (0.61, 1.21)
* Compared to historical data

Effect of Maraviroc on the Pharmacokinetics of Concomitant Drugs

Maraviroc is unlikely to inhibit the metabolism of co-administered drugs metabolized by the following cytochrome P enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, and CYP3A) because maraviroc did not inhibit activity of those enzymes at clinically relevant concentrations in vitro. Maraviroc does not induce CYP1A2 in vitro.

In vitro results indicate that maraviroc could inhibit P-glycoprotein in the gut and may thus affect bioavailability of certain drugs.

Drug interaction studies were performed with maraviroc and other drugs likely to be co-administered or commonly used as probes for pharmacokinetic interactions [see Table 6]. Maraviroc had no effect on the pharmacokinetics of zidovudine or lamivudine. Maraviroc had no clinically relevant effect on the pharmacokinetics of midazolam, the oral contraceptives ethinylestradiol and levonorgestrel, no effect on the urinary 6β-hydroxycortisol/cortisol ratio, suggesting no induction of CYP3A in vivo. Maraviroc had no effect on the debrisoquine metabolic ratio (MR) at 300 mg twice daily or less in vivo and did not cause inhibition of CYP2D6 in vitro until concentrations > 100μM. However, there was 234% increase in debrisoquine MR on treatment compared to baseline at 600 mg once daily, suggesting potential inhibition of CYP2D6 at higher dose.

Microbiology

Mechanism of Action

Maraviroc is a member of a therapeutic class called CCR5 co-receptor antagonists. Maraviroc selectively binds to the human chemokine receptor CCR5 present on the cell membrane, preventing the interaction of HIV-1 gp120 and CCR5 necessary for CCR5-tropic HIV-1 to enter cells. CXCR4-tropic and dual-tropic HIV-1 entry is not inhibited by maraviroc.

Antiviral Activity in Cell Culture

Maraviroc inhibits the replication of CCR5-tropic laboratory strains and primary isolates of HIV-1 in models of acute peripheral blood leukocyte infection. The mean EC50 value (50% effective concentration) for maraviroc against HIV-1 group M isolates (subtypes A to J and circulating recombinant form AE) and group O isolates ranged from 0.1 to 4.5 nM (0.05 to 2.3 ng/mL) in cell culture.

When used with other antiretroviral agents in cell culture, the combination of maraviroc was not antagonistic with NNRTIs (delavirdine, efavirenz and nevirapine), NRTIs (abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zalcitabine and zidovudine), or protease inhibitors (amprenavir, atazanavir, darunavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir and tipranavir). Maraviroc was additive/synergistic with the HIV fusion inhibitor enfuvirtide. Maraviroc was not active against CXCR4-tropic and dual-tropic viruses (EC50 value > 10 μM). The antiviral activity of maraviroc against HIV-2 has not been evaluated.

Resistance in Cell Culture

HIV-1 variants with reduced susceptibility to maraviroc have been selected in cell culture, following serial passage of two CCR5-tropic viruses (CC1/85 and RU570). The maraviroc-resistant viruses remained CCR5-tropic with no evidence of a change from a CCR5-tropic virus to a CXCR4-using virus. Two amino acid residue substitutions in the V3-loop region of the HIV-1 envelope glycoprotein (gp160), A316T and I323V (HXB2 numbering) were shown to be necessary for the maraviroc-resistant phenotype in the HIV-1 isolate CC1/85. In the RU570 isolate a 3-amino acid residue deletion in the V3 loop, ΔQAI (HXB2 positions 315-317), was associated with maraviroc resistance. The relevance of the specific gp120 mutations observed in maraviroc-resistant isolates selected in cell culture to clinical maraviroc resistance is not known. Maraviroc-resistant viruses were characterized phenotypically by concentration response curves that did not reach 100% inhibition in phenotypic drug assays, rather than increases in EC₅₀ values.

Cross-resistance in Cell Culture

Maraviroc had antiviral activity against HIV-1 clinical isolates resistant to NRTIs, NNRTIs, PIs and enfuvirtide in cell culture (EC50 values ranged from 0.7 to 8.9 nM (0.36 to 4.57 ng/mL)). Maravirocresistant viruses that emerged in cell culture remained susceptible to the fusion inhibitor enfuvirtide and the protease inhibitor saquinavir.

Clinical Resistance

Virologic failure on maraviroc can result from genotypic and phenotypic resistance to maraviroc or through outgrowth of undetected CXCR4-using virus present before maraviroc treatment (see Tropism below). Week 48 data from treatment-experienced subjects failing maraviroc-containing regimens with CCR5-tropic virus (n=58) have identified 22 viruses that had decreased susceptibility to maraviroc characterized in phenotypic drug assays by concentration response curves that did not reach 100% inhibition. Additionally, CCR5-tropic virus from 2 of these treatment failure subjects had ≥ 3-fold shifts in EC₅₀ values for maraviroc at the time of failure.

Fifteen of these viruses were sequenced in the gp120 encoding region and multiple amino acid substitutions with unique patterns in the heterogeneous V3 loop region were detected. Changes at either amino acid position 308 or 323 (HXB2 numbering) were seen in the V3 loop in 7 of the subjects with decreased maraviroc susceptibility. Substitutions outside the V3 loop of gp120 may also contribute to reduced susceptibility to maraviroc.

Tropism

In the majority of cases, treatment failure on maraviroc was associated with detection of CXCR4-using virus (i.e., CXCR4-or dual/mixed-tropic) which was not detected by the tropism assay prior to treatment. CXCR4-using virus was detected at failure in approximately 55% of subjects who failed treatment on maraviroc by Week 48, as compared to 9% of subjects who experienced treatment failure in the placebo arm. To investigate the likely origin of the on-treatment CXCR4-using virus, a detailed clonal analysis was conducted on virus from 20 representative subjects (16 subjects from the maraviroc arms and 4 subjects from the placebo arm) in whom CXCR4-using virus was detected at treatment failure. From analysis of amino acid sequence differences and phylogenetic data, it was determined that CXCR4-using virus in these subjects emerged from a low level of pre-existing CXCR4-using virus not detected by the tropism assay (which is population-based) prior to treatment rather than from a co-receptor switch from CCR5-tropic virus to CXCR4-using virus resulting from mutation in the virus.

Detection of CXCR4-using virus prior to initiation of therapy has been associated with a reduced virological response to maraviroc. Furthermore, subjects failing maraviroc BID at Week 48 with CXCR4-using virus had a lower median increase in CD4+ cell counts from baseline (+41 cells/mm³) than those subjects failing with CCR5-tropic virus (+162 cells/mm³). The median increase in CD4+ cell count in patients failing in the placebo arm was +7 cells/mm³.

Pharmacogenomics

The impact of CCR5 promoter and coding sequence polymorphisms on the efficacy of maraviroc is being evaluated.

Clinical Studies

The clinical efficacy and safety of SELZENTRY is derived from analyses of 48-week data from two ongoing studies, A4001027 (MOTIVATE-1) and A4001028 (MOTIVATE-2), in antiretroviral treatmentexperienced adult subjects infected with CCR5-tropic HIV-1. These studies are supported by a 48-week study in antiretroviral treatment-experienced adult subjects infected with dual/mixed-tropic HIV-1, A4001029.

Studies in CCR5-tropic, Treatment-Experienced Subjects

Studies A4001027 and A4001028 are ongoing, double-blind, randomized, placebo-controlled, multicenter studies in subjects infected with CCR5-tropic HIV-1. Subjects were required to have an HIV- 1 RNA of greater than 5,000 copies/mL despite at least 6 months of prior therapy with at least one agent from three of the four antiretroviral drug classes [ ≥ 1 nucleoside reverse transcriptase inhibitors (NRTI), ≥ 1 non-nucleoside reverse transcriptase inhibitors (NNRTI), ≥ 2 protease inhibitors (PI), and/or enfuvirtide] or documented resistance to at least one member of each class. All subjects received an optimized background regimen consisting of 3 to 6 antiretroviral agents (excluding low-dose ritonavir) selected on the basis of the subject's prior treatment history and baseline genotypic and phenotypic viral resistance measurements. In addition to the optimized background regimen, subjects were then randomized in a 2:2:1 ratio to maraviroc 300 mg once daily, maraviroc 300 mg twice daily, or placebo. Doses were adjusted based on background therapy as described in Dosing and Administration, Table 1.

In the pooled analysis for A4001027 and A4001028, the demographics and baseline characteristics of the treatment groups were comparable (Table 7). Of the 1043 subjects with a CCR5 tropism result at screening, 7.6% had a dual/mixed tropism result at the baseline visit 4 to 6 weeks later. This illustrates the background change from CCR5 to dual/mixed tropism result over time in this treatment-experienced population, prior to a change in antiretroviral regimen or administration of a CCR5 co-receptor antagonist.

Table 7 : Demographic and Baseline Characteristics of Subjects in Studies A4001027 and A4001028

	SELZENTRY BID N = 426	Placebo N = 209
Age(years)
Mean(Range)	46.3 (21-73)	45.7 (29-72)
Sex
Male	382 (89.7%)	185 (88.5%)
Female	44 (10.3%)	24 (11.5%)
Race
White	363 (85.2%)	178 (85.2%)
Black	51 (12.0%)	26 (12.4%)
Other	12 (2.8%)	5 (2.4%)
Region
U.S.	276 (64.8%)	135 (64.6%)
Non-U.S.	150 (35.2%)	74 (35.4%)
Subjects with Previous Enfuvirtide Use	142 (33.3%)	62 (29.7)
Subjects with Enfuvirtide as Part of OBT	182 (42.7%)	91 (43.5%)
Baseline Plasma HIV-1 RNA (log10 copies/mL) Mean (Range)	4.85 (2.96-6.88)	4.86 (3.46-7.07)
Subjects with Screening Viral Load ≥ 100,000 copies/mL	179 (42.0%)	84 (40.2%)
Baseline CD4+ Cell Count (cells/mm³) Median (Range)	167 (2-820)	171 (1-675)
Subjects with Baseline CD4+ Cell Count ≥ 200 cells/mm³)	250 (58.7%)	118 (56.5%)
Subjects with Overall Susceptibility Score (OSS):a
0	57 (13.4%)	35 (16.7%)
1	136 (31.9%)	44 (21.1%)
2	104 (24.4%)	59 (28.2%)
≥ 3	125 (29.3%)	66 (31.6%)
Subjects with enfuvirtide resistance mutations	90 (21.2%)	45 (21.5%)
Median Number of Resistance-Associated:b
PI mutations	10	10
NNRTI mutations	1	1
NRTI mutations	6	6
a OSS -Sum of active drugs in OBT based on combined information from genotypic and phenotypic testing. b Resistance mutations based on IAS guidelines1

The week 48 results for the pooled Studies A4001027 and A4001028 are shown in Table 8.

Table 8 : Outcomes of Randomized Treatment at Week 48 Studies A4001027 and A4001028

Outcome	SELZENTRY BID N=426	PLACEBO N=209		Mean Difference
Mean change from Baseline to Week 48 HIV-1 RNA (log10 copies/mL)	-1.84	-0.78		-1.05
< 400 copies/mL at Week 48	239 (56%)	47 (22%)		34%
< 400 copies/mL at Week 48	194 (46%)	35 (17%)		29%
Discontinuations
Insufficient Clinical Response	97 (23 %)	113(54%)
Adverse Events	19 (4%)	11(5%)
Other	27 (6%)	18(9%)
Patients with treatment-emergent CDC Category C events	22 (5%)	16(8%)
Deaths (during study or within 28 days of last dose)	9 (2%) a	1(0.5%)
a one additional subject died while receiving open-label maraviroc therapy subsequent to discontinuing double-blind placebo due to insufficient response

After 48 weeks of therapy, the proportion of subjects with HIV-1 RNA < 400 copies/mL receiving maraviroc compared to placebo was 56% and 22%, respectively. The mean changes in plasma HIV-1 RNA from baseline to week 48 were –1.84 log10 copies/mL for subjects receiving maraviroc + OBT compared to –0.78 log10 copies/mL for subjects receiving OBT only. The mean increase in CD4+ counts was higher on maraviroc twice daily + OBT (124 cells/mm³) than on placebo + OBT (60 cells/mm³ ).

Study in Dual/Mixed-tropic, Treatment-Experienced Subjects

Study A4001029 was an exploratory, randomized, double blind, multicenter trial to determine the safety and efficacy of maraviroc in subjects infected with dual/mixed co-receptor tropic HIV-1. The inclusion/exclusion criteria were similar to those for Studies A4001027 and A4001028 above and the subjects were randomized in a 1:1:1 ratio to SELZENTRY once daily, SELZENTRY twice daily, or placebo. No increased risk of infection or HIV disease progression was observed in the subjects who received SELZENTRY. SELZENTRY use was not associated with a significant decrease in HIV-1 RNA compared to placebo in these subjects and no adverse effect on CD4 count was noted.

¹ IAS-USA Drug Resistance Mutations Figures http://www.iasusa.org/pub/topics/2006/issue3/125.pdf

Last updated on RxList: 2/11/2009

MEDICATION GUIDE

SELZENTRY®
(sell-ZEN-tree)
(maraviroc) Tablets

Read the Medication Guide that comes with SELZENTRY before you start taking it and each time you get a refill. There may be new information. This information does not take the place of talking with your doctor about your medical condition or treatment.

What is the most important information I should know about SELZENTRY?

Liver problems

Liver problems (liver toxicity) have happened in patients taking SELZENTRY. An allergic reaction may happen before liver problems occur. Stop taking SELZENTRY and call your doctor right away if you get any of the following symptoms:

• an itchy rash on your body (allergic reaction)
• Your skin or eyes look yellow and/or dark (tea-colored) urine
• vomiting and/or upper right stomach area (abdominal) pain

You should see your doctor right away but continue taking SELZENTRY if you have any of the following other symptoms: nausea, fever, flu-like symptoms, fatigue

What is SELZENTRY?

SELZENTRY is an anti-HIV medicine called a CCR5 antagonist. HIV (Human Immunodeficiency Virus) is the virus that causes AIDS (Acquired Immune Deficiency Syndrome).

SELZENTRY is used with other anti-HIV medicines in adults with CCR5-tropic HIV-1 infection who are already taking anti-HIV medicines and the medicines are not controlling their HIV infection.

• SELZENTRY will not cure HIV infection.
• People taking SELZENTRY may still develop infections, including opportunistic infections or other conditions that happen with HIV infection.
• It is very important that you stay under the care of your doctor during treatment with SELZENTRY.
• The long-term effects of SELZENTRY are not known at this time.
• SELZENTRY has not been studied in children less than 16 years of age.

Does SELZENTRY lower the risk of passing HIV to other people?

No, SELZENTRY does not lower the risk of passing HIV to other people through sexual contact, sharing needles, or being exposed to your blood.

• Continue to practice safer sex.
• Use latex or polyurethane condoms or other barrier methods to lower the chance of sexual contact with any body fluids. This includes semen from a man, vaginal secretions from a woman, or blood.
• Never re-use or share needles.
• Ask your doctor if you have any questions about safer sex or how to prevent passing HIV to other people.

How does SELZENTRY work?

HIV enters cells in your blood by attaching itself to structures on the surface of the cell called receptors. SELZENTRY blocks a specific receptor called CCR5 that CCR5-tropic HIV-1 uses to enter CD4 or Tcells in your blood. Your doctor will do a blood test to see if you have been infected with CCR5-tropic HIV-1 before prescribing SELZENTRY for you.

• When used with other anti-HIV medicines, SELZENTRY may:
  • reduce the amount of HIV in your blood. This is called “viral load”.
  • increase the number of white blood cells called T (CD4) cells.

Both of these may keep your immune system healthy, so it can help fight infection.

SELZENTRY does not work in all patients with CCR5-tropic HIV-1 infection.

What should I tell my doctor before taking SELZENTRY?

Tell your doctor about all of your medical conditions, including if you:

• have any allergies
• have liver problems including a history of hepatitis B or C
• have heart problems
• have kidney problems
• have low blood pressure or take medicines to lower blood pressure
• are pregnant or planning to become pregnant. It is not known if SELZENTRY may harm your unborn baby. If you take SELZENTRY while you are pregnant, talk to your doctor about how you can be included in the Antiretroviral Pregnancy Registry.
• are breast-feeding or planning to breast-feed. It is recommended that HIV-positive women should not breastfeed their babies. This is because of the chance of passing HIV to your baby. Talk with your doctor about the best way to feed your baby.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements. Certain other medicines may affect the levels of SELZENTRY in your blood. Your doctor may need to change your dose of SELZENTRY when you take it with certain medicines.

Do not take products that contain St. John's Wort (hypericum perforatum). St. John's Wort may lower the levels of SELZENTRY in your blood so that it will not work to treat your CCR5-tropic HIV infection.

Know the medicines you take. Keep a list of your medicines. Show the list to your doctor and pharmacist when you get a new medicine.

How should I take SELZENTRY?

Take SELZENTRY exactly as prescribed by your doctor. SELZENTRY comes in 150 mg and 300 mg tablets. Your doctor will prescribe the dose that is right for you.

• Take SELZENTRY twice a day.
• Swallow SELZENTRY tablets whole. Do not chew the tablets.
• Take SELZENTRY tablets with or without food.
• Always take SELZENTRY with the other anti-HIV drugs prescribed by your doctor.

Do not change your dose or stop taking SELZENTRY or your other anti-HIV medicines without first talking with your doctor.

• If you take too much SELZENTRY, call your doctor or the poison control center right away.
• If you forget to take SELZENTRY, take the next dose of SELZENTRY as soon as possible and then take your next scheduled dose at its regular time. If it is less than 6 hours before your next dose, do not take the missed dose. Wait and take the next dose at the regular time. Do not take a double dose to make up for a missed dose.
• It is very important to take all your anti-HIV medicines as prescribed and at the same time each day. This can help your medicines work better. It also lowers the chance that your medicines will stop working to fight HIV (drug resistance).
• When your SELZENTRY supply starts to run low, ask your doctor or pharmacist for a refill. This is very important because the amount of virus in your blood may increase and SELZENTRY could stop working if it is stopped for even a short period of time.

What are the possible side effects of SELZENTRY?

When SELZENTRY has been given with other anti-HIV drugs, there have been serious side effects including:

• Liver problems. See “What is the most important information I should know about SELZENTRY?”
• Heart problems including heart attack
• Low blood pressure when standing up (postural hypotension). Low blood pressure when standing up can cause dizziness or fainting. Do not drive a car or operate heavy machinery if you have dizziness while taking SELZENTRY.
• Changes in your immune system. A condition called Immune Reconstitution Syndrome can happen when you start taking HIV medicines. Your immune system may get stronger and could begin to fight infections that have been hidden in your body such as pneumonia, herpes virus or tuberculosis. Tell your doctor if you develop new symptoms after starting your HIV medicines.
• Possible chance of infection or cancer. SELZENTRY affects other immune system cells and therefore may possibly increase your chance for getting other infections or cancer, although there is no evidence from the clinical trials of an increase in serious infections or cancer.

The most common side effects of SELZENTRY include colds, cough, fever, rash, and dizziness. Tell your doctor about any side effect that bothers you or does not go away.

These are not all of the side effects with SELZENTRY. For more information, ask your doctor or pharmacist.

How should I store SELZENTRY?

• Store SELZENTRY tablets at room temperature from 59°F to 86°(15°C to 30°C)] .
• Safely throw away medicine that is out of date or that you no longer need.
• Keep SELZENTRY and all medicines out of the reach of children.

General information about SELZENTRY

Medicines are sometimes prescribed for conditions that are not mentioned in Medication Guides. Do not use SELZENTRY for a condition for which it was not prescribed. Do not give SELZENTRY to other people, even if they have the same symptoms you have. It may harm them.

This Medication Guide summarizes the most important information about SELZENTRY. If you would like more information, talk with your doctor. You can ask your doctor or pharmacist for more information about SELZENTRY that is written for health professionals. For more information go to www.selzentry.com.

What are the ingredients in SELZENTRY?

Active Ingredient: maraviroc

Inactive Ingredients:

Tablet core: microcrystalline cellulose, dibasic calcium phosphate (anhydrous), sodium starch glycolate, magnesium stearate

Film-coat: FD&C blue #2 aluminum lake, soya lecithin, polyethylene glycol (macrogol 3350), polyvinyl alcohol, talc and titanium dioxide

This Medication Guide has been approved by the US Food and Drug Administration

Last updated on RxList: 2/11/2009

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

MARAVIROC - ORAL

COMMON BRAND NAME(S): Selzentry

WARNING: This medication may rarely cause serious liver problems. Symptoms of a serious allergic reaction may occur before liver problems develop. Tell your doctor immediately if you notice any symptoms of a serious allergic reaction or possible liver damage such as: rash, persistent nausea/vomiting, yellowing eyes/skin, dark urine, extreme tiredness. (See also Side Effects section.)

USES: Maraviroc, used with other medications, helps control your HIV infection, thereby improving your quality of life. It also lowers your risk of getting complications from HIV disease (e.g., new infections, cancer). Maraviroc belongs to a class of drugs known as entry inhibitors. It works by blocking the HIV virus from infecting healthy immune cells (T-cells).

This medication is not a cure for HIV infection, and it does not prevent the spread of HIV to others through sexual contact or blood contamination (e.g., sharing used needles).

HOW TO USE: Read the Medication Guide provided by your pharmacist before you start using maraviroc and each time you get a refill. If you have any questions, consult your doctor or pharmacist. Take this medication by mouth with or without food, usually twice daily or as directed by your doctor.

Dosage is based on your medical condition, response to treatment, and other medications you may be taking.

It is very important to continue taking this medication (and other HIV medications) exactly as prescribed by your doctor.

This medication works best when the amount of drug in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same times each day.

Do not take more or less of this drug than prescribed or stop taking it (or other HIV medicines) even for a short time unless directed to do so by your doctor. Doing so may cause the amount of virus to increase, make the infection more difficult to treat (resistant), or worsen side effects.

SIDE EFFECTS: See also Warning section.

Cough, stomach pain, tiredness, or muscle/joint pain may occur. Lightheadedness or dizziness while standing may also occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Seek immediate medical attention if any of these rare but very serious side effects occur: chest/jaw/left arm pain.

If you are taking HIV medications for the first time, you may experience symptoms of an old infection. This may happen as your immune system begins to work better. Symptoms may include: new cough, trouble breathing, fever, new vision problems, new headaches, new skin problems.

Contact your doctor immediately if you have any of these effects.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any of the following symptoms: rash, itching/swelling (especially of tongue/lips/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking maraviroc, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

Before taking this medication, tell your doctor or pharmacist your medical history, especially of: heart disease (e.g., previous heart attack), kidney disease, liver problems (including hepatitis B or C infection), low blood pressure.

This drug may make you dizzy. Use caution while driving, using machinery, or doing any other activity that requires alertness. To reduce dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. Limit alcoholic beverages.

Tell your doctor if you are pregnant before using this medication.

It is not known if this medication passes into breast milk. Because breast milk can transmit HIV, do not breast-feed.

DRUG INTERACTIONS: Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

This drug should not be used with the following product because very serious interactions may occur: St John's wort.

If you are currently using the product listed above, tell your doctor or pharmacist before starting maraviroc.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: drugs for high blood pressure, other drugs for HIV (e.g., ritonavir, saquinavir, lopinavir/ritonavir), drugs affecting liver enzymes that remove maraviroc from your body (such as cimetidine, nefazodone, azole antifungals including itraconazole/ketoconazole, macrolide antibiotics including erythromycin, rifamycins including rifampin, certain anti-seizure medicines including carbamazepine).

If any of these medications are taken with maraviroc, your doctor may change your dose of maraviroc or the other drug(s), or your doctor may monitor you specially. Consult your doctor or pharmacist for more details.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor or pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US National Poison Hotline at 1-800-222-1222. Canada residents can call a provincial poison control center.

NOTES: To decrease your risk of spreading HIV disease to others, always use an effective barrier method (e.g., latex or polyurethane condoms/dental dams) during sexual activity. Consult your doctor or pharmacist for more details.

Do not share this medication with others.

Laboratory and/or medical tests (e.g., liver function tests, viral load, T-cell counts) should be performed regularly to monitor your progress or check for side effects. Consult your doctor for more details.

Keep all medical and laboratory appointments.

MISSED DOSE: If you miss a dose, take it as soon as you remember unless it is less than 6 hours until the next dose. In that case, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-800-854-1166 (USA) or 1-800-668-1507 (Canada).

Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.