2.1 General Dosing Considerations

• Nevirapine extended-release tablets must be swallowed whole and must not be chewed, crushed, or divided.
• Children should be assessed for their ability to swallow tablets before prescribing nevirapine extended-release tablets.
• Nevirapine extended-release tablets can be taken with or without food.
• No recommendations can be made regarding substitution of four nevirapine extended-release 100 mg tablets for one nevirapine extended-release 400 mg tablet.

2.2 Adult Patients

Patients not currently taking immediate-release nevirapine

Patients must initiate therapy with one 200 mg tablet of immediate-release nevirapine daily for the first 14 days in combination with other antiretroviral agents. The 14-day  lead-in period with nevirapine tablets 200 mg daily dosing must be strictly followed (the lead-in period has been observed to decrease the incidence of rash), followed by one 400 mg tablet of nevirapine extended-release once daily [see Dosage and Administration (2.5)  and  Warnings and Precautions (5.2)]. If rash persists beyond the 14-day lead-in period with immediate-release nevirapine, do not begin dosing with nevirapine extended-release tablets. The lead-in dosing with 200 mg once daily immediate-release nevirapine should not be continued beyond 28 days, at which point an alternative regimen should be sought.

Switching patients from immediate-release nevirapine to nevirapine extended-release tablets

Patients already on a regimen of immediate-release nevirapine twice daily in combination with other antiretroviral agents can be switched to nevirapine extended-release tablets 400 mg once daily without the 14-day lead-in period. Patients already on a regimen of immediate-release nevirapine twice daily who switch to nevirapine extended-release tablets therapy should continue with their ongoing clinical and laboratory monitoring.

2.3 Pediatric Patients

Nevirapine extended-release tablets in pediatric patients is dosed based on body surface area (BSA) calculated using the Mosteller formula. All pediatric patients must initiate therapy with immediate-release Nevirapine (as 150 mg/m2 of Nevirapine Oral Suspension or as Nevirapine tablets), at a dose not to exceed 200 mg per day, administered once daily for the first 14 days. This lead-in period should be used because it has been demonstrated to reduce the frequency of rash. This lead-in period is not required if the patient is already on a regimen of twice daily immediate-release formulation in combination with other antiretroviral agents.

The recommended oral dose of Nevirapine extended-release tablets for pediatric patients with a BSA of 1.17 m2 or greater is 400 mg following the lead-in period with immediate-release Nevirapine. The total daily dose should not exceed 400 mg for any patient. 

2.4 Monitoring of Patients

Intensive clinical and laboratory monitoring, including liver enzyme tests, is essential at baseline and during the first 18 weeks of treatment with nevirapine. The optimal frequency of monitoring during this period has not been established. Some experts recommend clinical and laboratory monitoring more often than once per month, and in particular, would include monitoring of liver enzyme tests prior to beginning the 14-day lead-in period with immediate-release nevirapine, prior to initiation of nevirapine extended-release tablets, and at two weeks after initiation of nevirapine extended-release tablets therapy. After the initial 18-week period, frequent clinical and laboratory monitoring should continue throughout nevirapine extended-release tablets treatment [see Warnings and Precautions (5)]. In some cases, hepatic injury has progressed despite discontinuation of treatment.



Patients already on a regimen of immediate-release nevirapine twice daily who switch to nevirapine extended-release tablets once daily should continue with their ongoing clinical and laboratory monitoring.

2.5 Dosage Adjustment

Patients with Rash



Discontinue nevirapine if a patient experiences severe rash or any rash accompanied by constitutional findings [see  Warnings and Precautions (5.2)]. Do not initiate therapy with nevirapine extended-release tablets if a patient experiences mild to moderate rash without constitutional symptoms during the 14-day lead-in period of immediate-release nevirapine until the rash has resolved [see Warnings and Precautions (5.2)].  The total duration of the once daily lead-in dosing period should not exceed 28 days at which point an alternative regimen should be sought.



Patients with Hepatic Events



If a clinical (symptomatic) hepatic event occurs, permanently discontinue nevirapine. Do not restart nevirapine after recovery [see Warnings and Precautions (5.1)].



Patients with Dose Interruption



For patients who interrupt nevirapine extended-release tablets dosing for more than 7 days, restart the recommended lead-in dosing with immediate-release nevirapine, using one 200 mg tablet daily for the first 14 days.



Patients with Renal Impairment



Patients with CrCl greater than or equal to 20 mL per min and not requiring dialysis do not require an adjustment in dosing. The pharmacokinetics of nevirapine have not been evaluated in patients with CrCl  less than 20 mL per min. An additional 200 mg dose of immediate-release nevirapine following each dialysis treatment is indicated in patients requiring dialysis. Nevirapine metabolites may accumulate in patients receiving dialysis; however, the clinical significance of this accumulation is not known [see Clinical Pharmacology (12.3)]. Nevirapine extended-release tablets have not been studied in patients with renal dysfunction.

5.1 Hepatotoxicity and Hepatic Impairment

Severe, life-threatening, and in some cases fatal hepatotoxicity, including fulminant and cholestatic hepatitis, hepatic necrosis and hepatic failure, have been reported in patients treated with nevirapine.



The risk of symptomatic hepatic events regardless of severity is greatest in the first 6 weeks of therapy. The risk continued to be greater in the nevirapine groups in controlled clinical trials through 18 weeks of treatment. However, hepatic events may occur at any time during treatment. In some cases, patients presented with non-­specific, prodromal signs or symptoms of fatigue, malaise, anorexia, nausea, jaundice, liver tenderness or hepatomegaly, with or without initially abnormal serum transaminase levels. Rash was observed in approximately half of the patients with symptomatic hepatic adverse events. Fever and flu-like symptoms accompanied some of these hepatic events. Some events, particularly those with rash and other symptoms, have progressed to hepatic failure with transaminase elevation, with or without hyperbilirubinemia, hepatic encephalopathy, prolonged partial thromboplastin time, or eosinophilia. Rhabdomyolysis has been observed in some patients experiencing skin and/or liver reactions associated with nevirapine use. Hepatitis/hepatic failure may be associated with signs of hypersensitivity which can include severe rash or rash accompanied by fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, facial edema, eosinophilia, granulocytopenia, lymphadenopathy, or renal dysfunction. Patients with signs or symptoms of hepatitis must be advised to discontinue nevirapine and immediately seek medical evaluation, which should include liver enzyme tests.



The first 18 weeks of therapy with nevirapine extended-release tablets are a critical period during which intensive clinical and laboratory monitoring of patients is required to detect potentially life-threatening hepatic events. The optimal frequency of monitoring during this period has not been established. Some experts recommend clinical and laboratory monitoring more often than once per month, and in particular, include monitoring of liver enzyme tests at baseline, prior to dose escalation and at two weeks post-dose escalation. After the initial 18-week period, frequent clinical and laboratory monitoring should continue throughout nevirapine extended-release tablets treatment.



Transaminases should be checked immediately if a patient experiences signs or symptoms suggestive of hepatitis and/or hypersensitivity reaction. Transaminases should also be checked immediately for all patients who develop a rash in the first 18 weeks of treatment. Physicians and patients should be vigilant for the appearance of signs or symptoms of hepatitis, such as fatigue, malaise, anorexia, nausea, jaundice, bilirubinuria, acholic stools, liver tenderness, or hepatomegaly. The diagnosis of hepatotoxicity should be considered in this setting, even if transaminases are initially normal or alternative diagnoses are possible [see Dosage and Administration (2.4)].



If clinical hepatitis or transaminase elevations combined with rash or other systemic symptoms occur, permanently discontinue nevirapine. Do not restart nevirapine after recovery. In some cases, hepatic injury progresses despite discontinuation of treatment.



The patients at greatest risk of hepatic events, including potentially fatal events, are women with high CD4+ cell counts. In a retrospective analysis of pooled clinical trials with immediate-release nevirapine, during the first 6 weeks of treatment women had a 3-fold higher risk than men for symptomatic, often rash-associated, hepatic events (6% versus 2%). Patients with higher CD4+ cell counts at initiation of nevirapine therapy are at higher risk for symptomatic hepatic events. Women with CD4+ cell counts greater than 250 cells/mm3 had a 12-fold higher risk of symptomatic hepatic adverse events compared to women with CD4+ cell counts less than 250 cells/mm3(11% versus 1%). An increased risk was observed in men with CD4+ cell counts greater than 400 cells/mm3  (6% versus 1% for men with CD4+ cell counts less than 400 cells/mm3). However, all patients, regardless of gender, CD4+ cell count, or antiretroviral treatment history, should be monitored for hepatotoxicity since symptomatic hepatic adverse events have been reported at all CD4+ cell counts. Co-infection with hepatitis B or C and/or increased transaminase elevations at the start  of therapy with nevirapine are associated with a greater risk of later symptomatic events (6 weeks or more after starting nevirapine) and asymptomatic increases in AST or ALT.



In addition, serious hepatotoxicity (including liver failure requiring transplantation in one instance) has been reported in HIV-1 uninfected individuals receiving multiple doses of immediate-release nevirapine in the setting of post-exposure prophylaxis (PEP), an unapproved use. Use of nevirapine extended-release tablets for occupational and non-occupational PEP is contraindicated [see Contraindications (4)].



Increased nevirapine trough concentrations have been observed in some patients with hepatic fibrosis or cirrhosis. Therefore, carefully monitor patients with either hepatic fibrosis or cirrhosis for evidence of drug-induced toxicity. Do not administer nevirapine to patients with moderate or severe (Child-Pugh Class B or C, respectively) hepatic impairment [see Contraindications (4), Use in Specific Populations (8.7), and Clinical Pharmacology (12.3)]. Nevirapine extended-release tablets have not been evaluated in subjects with hepatic impairment.

5.2 Skin Reactions

Severe and life-threatening skin reactions, including fatal cases, have been reported in patients taking nevirapine. These have occurred most frequently during the first 6 weeks of therapy. These have included cases of Stevens-Johnson syndrome, toxic epidermal necrolysis, and hypersensitivity reactions characterized by rash, constitutional findings, and organ dysfunction including hepatic failure. Rhabdomyolysis has been observed in some patients experiencing skin and/or liver reactions associated with nevirapine use.



Patients developing signs or symptoms of severe skin reactions or hypersensitivity reactions (including, but not limited to, severe rash or rash accompanied by fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, facial edema, and/or hepatitis, eosinophilia, granulocytopenia, lymphadenopathy, and renal dysfunction) must permanently discontinue nevirapine and seek medical evaluation immediately. Do not restart nevirapine following severe skin rash, skin rash combined with increased transaminases or other symptoms, or hypersensitivity reaction.



The first 18 weeks of therapy with nevirapine extended-release tablets are a critical period during which intensive clinical and laboratory monitoring of patients is required to detect potentially life-threatening skin reactions. The optimal frequency of monitoring during this period has not been established. Some experts recommend clinical and laboratory monitoring more often than once per month, and in particular, include monitoring of liver enzyme tests at baseline, prior to dose escalation and at two weeks post-dose escalation. After the initial 18-week period, frequent clinical and laboratory monitoring should continue throughout nevirapine extended-release tablets treatment. In addition, the 14-day lead-in period with nevirapine 200 mg daily dosing has been demonstrated to reduce the frequency of rash [see Dosage and Administration (2.2)].



If patients present with a suspected nevirapine-associated rash, measure transaminases immediately. Permanently discontinue nevirapine in patients with rash-associated transaminase elevations [see Warnings and Precautions (5.1)].



Patients must initiate therapy with immediate-release nevirapine daily for the first 14 days. This lead-in period has been shown to reduce the frequency of rash. Discontinue nevirapine if a patient experiences severe rash or any rash accompanied by constitutional findings. Do not initiate nevirapine extended-release tablets if a patient experiencing a mild to moderate rash without constitutional symptoms during the 14-day immediate-release nevirapine lead-in period of 200 mg/day (150 mg/m2/day in pediatric patients) until the rash has resolved. The total duration of the immediate-release nevirapine lead-in dosing period must not exceed 28 days at which point an alternative regimen should be sought [see Dosage and Administration (2.5)]. Patients must be monitored closely if isolated rash of any severity occurs. Delay in stopping nevirapine treatment after the onset of rash may result in a more serious reaction.



Women appear to be at higher risk than men of developing rash with nevirapine.



In a clinical trial of immediate-release nevirapine, concomitant prednisone use (40 mg per day for the first 14 days of nevirapine administration) was associated with an increase in incidence and severity of rash during the first 6 weeks of nevirapine therapy. Therefore, use of prednisone to prevent nevirapine-associated rash is not recommended.

5.3 Resistance

Nevirapine extended-release tablets must not be used as a single agent to treat HIV-1 or added on as a sole agent to a failing regimen. Resistant virus emerges rapidly when nevirapine is administered as monotherapy. The choice of new antiretroviral agents to be used in combination with nevirapine should take into consideration the potential for cross resistance. When discontinuing an antiretroviral regimen containing nevirapine extended-release tablets, the long half-life of nevirapine should be taken into account; if antiretrovirals with shorter half-lives than nevirapine are stopped concurrently, low plasma concentrations of nevirapine alone may persist for a week or longer and virus resistance may subsequently develop [see Microbiology  (12.4)].

5.4 Drug Interactions

See Table 3 for listings of established and potential drug interactions [see Drug Interactions (7)].



Concomitant use of St. John's wort (Hypericum perforatum) or St. John's wort-containing products and nevirapine is not recommended. Co-administration of St. John’s wort with non-nucleoside reverse transcriptase inhibitors (NNRTIs), including nevirapine, is expected to substantially decrease NNRTI concentrations and may result in sub-optimal levels of nevirapine and lead to loss of virologic response and possible resistance to nevirapine or to the class of NNRTIs.



Co-administration of nevirapine and efavirenz is not recommended as this combination has been associated with an increase in adverse reactions and no improvement in efficacy.

5.5 Immune Reconstitution Syndrome

Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including nevirapine. 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 Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci  pneumonia, or tuberculosis), which may necessitate further evaluation and treatment.



Autoimmune disorders (such as Graves’ disease, polymyositis, and Guillain-Barré syndrome) have also been reported to occur in the setting of immune reconstitution, however, the time to onset is more variable, and can occur many months after initiation of treatment.

5.6 Fat Redistribution

Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and “cushingoid appearance” have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.

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



Clinical Trial Experience in Adult Patients



The most serious adverse reactions associated with nevirapine are hepatitis, hepatic failure, Stevens-Johnson syndrome, toxic epidermal necrolysis, and hypersensitivity reactions. Hepatitis/hepatic failure may be isolated or associated with signs of hypersensitivity which may include severe rash or rash accompanied by fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, facial edema, eosinophilia, granulocytopenia, lymphadenopathy, or renal dysfunction [see  Boxed  Warning  and Warnings and Precautions (5.1,  5.2)].



The most common clinical toxicity of nevirapine is rash, which can be severe or life-threatening [see Boxed Warning  and Warnings and Precautions (5.2)]. Rash occurs most frequently within the first 6 weeks of therapy. Rashes are usually mild to moderate, maculopapular erythematous cutaneous eruptions, with or without pruritus, located on the trunk, face and extremities.



The safety database in nevirapine extended-release tablets clinical trials contains data from 800 subjects treated with nevirapine extended-release tablets and 654 subjects treated with immediate release nevirapine.



Trial 1100.1486 (VERxVE)



In Trial 1100.1486 (VERxVE) treatment-naïve subjects received a lead-in dose of immediate-release nevirapine 200 mg once daily for 14 days (n=1068) and then were randomized to receive either immediate-release nevirapine 200 mg twice daily (n=506) or nevirapine extended-release tablets 400 mg once daily (n=505). All subjects received tenofovir + emtricitabine as background therapy. Subjects were enrolled with CD4+ counts less than 250 cells/mm3 for women and less than 400 cells/mm3 for men [see Indications and Usage (1)]. Data on potential symptoms of hepatic events were prospectively collected in this trial. The safety data include all subject visits up to the time of the last subject’s completion of the 96-week endpoint in the trial (mean observation period 98 weeks).



After the lead-in period, the incidence of any hepatic event was 9% in the immediate-release nevirapine group and 6% in the nevirapine extended-release tablets group; the incidence of symptomatic hepatic events (anorexia, jaundice, vomiting) was 3% and 2%, respectively. The incidence of GRADE 3 or 4 ALT/AST elevation was 8% in both the immediate-release nevirapine group and nevirapine extended-release tablets group. Overall, there was a comparable incidence of symptomatic hepatic events among men and women enrolled in VERxVE.



Severe or life-threatening rash considered to be related to nevirapine treatment occurred in 1% of subjects during the lead-in phase with immediate-release nevirapine, and in 1% of subjects in either treatment group during the randomization phase. In addition, six cases of Stevens-Johnson syndrome were reported in the trial; all but one occurred within the first 30 days of nevirapine treatment.



No Grade 2 or above adverse reactions judged to be related to treatment by the investigator occurred in more than 2% of subjects during the 14-day lead-in with immediate-release nevirapine (200 mg once daily), except for rash which occurred in 4% of subjects.



Adverse reactions of at least moderate intensity (Grades 2 or above) 2% or more of treatment-naïve subjects receiving either immediate-release nevirapine or nevirapine extended-release tablets after randomization in Trial 1100.1486 are shown in Table 1.

Laboratory Abnormalities



Liver enzyme test abnormalities (AST, ALT) were observed in subjects receiving nevirapine extended-release tablets. Asymptomatic elevations in GGT occur frequently but are not a contraindication to continue therapy with nevirapine in the absence of elevations in other liver enzyme tests. Laboratory abnormalities that occurred in trial 1100.1486 are shown in Table 2.

Trial 1100.1526 (TRANxITION)



In Trial 1100.1526 (TRANxITION) subjects on immediate-release nevirapine 200 mg twice daily for at least 18 weeks were randomized to either receive nevirapine extended-release tablets 400 mg once daily (n=295) or remain on their immediate-release nevirapine treatment (n=148). Adverse reactions observed for nevirapine extended-release tablets subjects (48 week analysis) were similar to those observed in trial 1100.1486, as displayed in Table 1.



Clinical Trial Experience in Pediatric Patients



Adverse reactions were assessed in Trial 1100.1518, an open-label, multiple-dose, non-randomized, cross-over trial to evaluate the safety and steady-state pharmacokinetic parameters of nevirapine extended-release tablets in HIV-1-infected pediatric subjects 3 to less than 18 years of age. Safety was further examined in an optional extension phase of the trial. Forty subjects who completed the pharmacokinetic part of the trial were treated with nevirapine extended-release tablets once daily in combination with other antiretrovirals for a median duration of 33 weeks. The most frequently reported adverse reactions related to nevirapine extended-release tablets in pediatric subjects were similar to those observed in adults. In pediatric subjects the incidence of Grade 2 or higher drug-related rash was 1%. There were no adverse reactions of Grade 2 or above which were considered to be related to treatment by the investigator that occurred in more than 1% of subjects [see Use in Specific Populations (8.4),  Clinical Pharmacology (12.3), and Clinical Studies (14.2)].

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-approval use of immediate-release nevirapine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.



Body as a Whole: fever, somnolence, drug withdrawal [see Drug Interactions (7)], redistribution/accumulation of body fat [see Warnings and Precautions (5.6)]



Gastrointestinal: vomiting



Liver and Biliary: jaundice, fulminant and cholestatic hepatitis, hepatic necrosis, hepatic failure



Hematology: anemia, eosinophilia, neutropenia



Investigations: decreased serum phosphorus



Musculoskeletal: arthralgia, rhabdomyolysis associated with skin and/or liver reactions



Neurologic: paraesthesia



Skin and Appendages: Allergic reactions including anaphylaxis, angioedema, bullous eruptions, ulcerative stomatitis and urticaria have all been reported. In addition, hypersensitivity syndrome and hypersensitivity reactions with rash associated with constitutional findings such as fever, blistering, oral lesions, conjunctivitis, facial edema, muscle or joint aches, general malaise, fatigue, or significant hepatic abnormalities [see Warnings and Precautions (5.1)] plus one or more of the following: hepatitis, eosinophilia, granulocytopenia, lymphadenopathy, and/or renal dysfunction have been reported.

8.1 Pregnancy

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to nevirapine during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.

Risk Summary



Available data from the APR show no difference in the risk of overall major birth defects for nevirapine compared with the background rate for major birth defects of 2.7% in a U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP) [see Data]. The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in clinically recognized pregnancies in the U.S. general population is 15 to 20%. The background risk of birth defects and miscarriage for the indicated population is unknown. Methodological limitations of the APR include the use of MACDP as the external comparator group. The MACDP population is not disease-specific, evaluates women and infants from a limited geographic area, and does not include outcomes for births that occurred at <20 weeks gestation.



There is a risk for severe hepatic events in pregnant women exposed to nevirapine extended-release tablets [see Clinical Considerations]. In animal reproduction studies, no evidence of adverse developmental outcomes was observed following oral administration of nevirapine during organogenesis in the rat and rabbit, at systemic exposures (AUC) to nevirapine approximately equal (rats) and 50% higher (rabbits) than the exposure in humans at the recommended 400 mg daily dose [see Data].



Clinical Considerations

Maternal adverse reactions

Severe hepatic events, including fatalities, have been reported in pregnant women receiving chronic nevirapine therapy as part of combination treatment of HIV-1 infection. Regardless of pregnancy status, women with CD4+ cell counts greater than 250 cells/mm3 should not initiate nevirapine unless the benefit outweighs the risk. It is unclear if pregnancy augments the risk observed in non-pregnant women [see Warnings and Precautions (5.1)].

Data



Human Data



Based on prospective reports to the APR of exposures to nevirapine during pregnancy resulting in live births (including over 1100 exposed in the first trimester and over 1500 exposed in the second/third trimester), the prevalence of birth defects in live births was 3.0% (95% CI: 2.1%, 4.1%) and 3.3% (95% CI: 2.4%, 4.3%) following first and second/third-trimester exposure, respectively, to nevirapine-containing regimens, compared with the background birth defect rate of 2.7% in a U.S. reference population of the MACDP.



Animal Data



Nevirapine was administered orally to pregnant rats (at 0, 12.5, 25, and 50 mg/kg/day), and rabbits (at 0, 30, 100, and 300 mg/kg/day) through organogenesis (on gestation days 7 through 16 and 6 through 18, respectively). No adverse developmental effects were observed at doses producing systemic exposures (AUC) approximately equivalent to (rats) or approximately 50% higher (rabbits) than human exposure at the recommended daily dose. In rats, decreased fetal body weights were observed at a maternally toxic dose at an exposure approximately 50% higher than the recommended daily dose.

8.2 Lactation

Risk Summary



The Centers for Disease Control and Prevention recommend that HIV-1 infected mothers in the United States not breastfeed their infants to avoid risking postnatal transmission of HIV-1 infection. Published data report that immediate-release nevirapine is present in human milk. There are limited data on the effects of nevirapine on the breastfed infant. There is no information on the effects of nevirapine on milk production. Because of the potential for (1) HIV-1 transmission (in HIV-negative infants), (2) developing viral resistance (in HIV-positive infants), and (3) serious adverse reactions in nursing infants, mothers should not breastfeed if they are receiving nevirapine extended-release tablets.

8.3 Females and Males of Reproductive Potential

Infertility



Limited human data are insufficient to determine the risk of infertility in humans. Based on results from animal fertility studies conducted in rats, nevirapine extended-release tablets may reduce fertility in females of reproductive potential. It is not known if these effects on fertility are reversible [see Nonclinical Toxicology (13.1)].

8.4 Pediatric Use

Nevirapine extended-release tablets are indicated for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in children 6 years of age or older with a BSA of 1.17 m2 or greater  [see Indications and Usage (1) and Dosage and Administration (2.3)].



The use of nevirapine extended-release tablets for the treatment of HIV-1 infection in pediatric patients 6 to less than 18 years of age is based on pharmacokinetic, safety, and antiviral activity data from an open-label trial with nevirapine extended-release tablets. The results of this trial were supported by previous demonstration of efficacy in adult patients [see Adverse Reactions (6.1), Clinical Pharmacology (12.3), and Clinical Studies (14.2)].



Nevirapine extended-release tablets are not recommended for children less than 6 years of age. Trial 1100.1518 did not provide sufficient pharmacokinetic data for children 3 to less than 6 years of age to support the use of nevirapine extended-release tablets in this age group. Furthermore, nevirapine extended-release tablets are not recommended for children less than 3 years of age because they are not able to swallow tablets.

8.5 Geriatric Use

Clinical studies of nevirapine extended-release tablets did not include sufficient numbers of subjects aged 65 and older to determine whether elderly subjects respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

8.6 Renal Impairment

In subjects with renal impairment (mild, moderate or severe), there were no significant changes in the pharmacokinetics of nevirapine. Nevirapine is extensively metabolized by the liver and nevirapine metabolites are extensively eliminated by the kidney. Nevirapine metabolites may accumulate in patients receiving dialysis; however, the clinical significance of this accumulation is not known. No adjustment in nevirapine dosing is required in patients with CrCl greater than or equal to 20 mL per min. The pharmacokinetics of nevirapine have not been evaluated in patients with CrCl less than 20 mL per min. In patients undergoing chronic hemodialysis, an additional dose of immediate-release nevirapine (200 mg) following each dialysis treatment is indicated [see  Dosage and Administration (2.5)  and Clinical Pharmacology (12.3)]. Nevirapine extended-release tablets have not been studied in patients with renal dysfunction.

8.7 Hepatic Impairment

Because increased nevirapine levels and nevirapine accumulation may be observed in patients with serious liver disease, do not administer nevirapine to patients with moderate or severe (Child-Pugh Class B or C, respectively) hepatic impairment [see Contraindications (4),  Warnings and Precautions (5.1), and Clinical Pharmacology (12.3)]. Nevirapine extended-release tablets have not been evaluated in subjects with hepatic impairment.

12.1 Mechanism of Action

Nevirapine is an antiretroviral drug [see Microbiology (12.4)].

12.3 Pharmacokinetics

Adults



Absorption and Bioavailability



The single-dose pharmacokinetics of nevirapine extended-release tablets was studied in 17 healthy volunteers. Nevirapine was absorbed with a median tmax of approximately 24 hrs. The mean Cmax   and AUC0-∞ of nevirapine were 2060 ng per mL and 161,000 ng*hr/mL, respectively. The bioavailability of 400 mg of nevirapine extended-release tablets, relative to 400 mg of immediate-release nevirapine, was approximately 75%.



The multiple-dose pharmacokinetics of nevirapine extended-release tablets was studied in 24 HIV-1 infected subjects who switched from chronic nevirapine IR to nevirapine extended-release tablets. The mean nevirapine AUC0-24,ss   and Cmin,ss   after 19 days of nevirapine extended-release tablets dosing under fasted conditions were 82,000 ng*hr/mL and 2920 ng per mL, respectively. When nevirapine extended-release tablets was administered under fed conditions, the mean nevirapine AUC0-24,ss   and Cmin,ss   were 96,700 ng*hr/mL and 3150 ng per mL, respectively. The bioavailability of 400 mg of nevirapine extended-release tablets, relative to 400 mg of immediate-release nevirapine, under fasted and fed conditions, was 80% and 94%, respectively. The difference in the bioavailability of nevirapine, when nevirapine extended-release tablets are dosed under fasted or fed conditions, is not considered clinically relevant. Nevirapine extended-release tablets can be taken with or without food.



Distribution



Nevirapine is highly lipophilic and is essentially nonionized at physiologic pH. Following intravenous administration to healthy adults, the apparent volume of distribution (Vdss) of nevirapine was 1.21 ± 0.09 L/kg, suggesting that nevirapine is widely distributed in humans. Nevirapine readily crosses the placenta and is also found in breast milk [see Use in Specific Populations (8.2)]. Nevirapine is about 60% bound to plasma proteins in the plasma concentration range of 1 to 10 mcg per mL. Nevirapine concentrations in human cerebrospinal fluid (n=6) were 45% (±5%) of the concentrations in plasma; this ratio is approximately equal to the fraction not bound to plasma protein.



Metabolism/Elimination



In vivo studies in humans and in vitro studies with human liver microsomes have shown that nevirapine is extensively biotransformed via cytochrome P450 (oxidative) metabolism to several hydroxylated metabolites. In vitro studies with human liver microsomes suggest that oxidative metabolism of nevirapine is mediated primarily by cytochrome P450 (CYP) isozymes from the CYP3A and CYP2B6 families, although other isozymes may have a secondary role. In a mass balance/excretion trial in eight healthy male volunteers dosed to steady state with immediate-release nevirapine 200 mg given twice daily followed by a single 50 mg dose of 14C-nevirapine, approximately 91.4 ± 10.5% of the radiolabeled dose was recovered, with urine (81.3 ± 11.1%) representing the primary route of excretion compared to feces (10.1 ± 1.5%). Greater than 80% of the radioactivity in urine was made up of glucuronide conjugates of hydroxylated metabolites. Thus, cytochrome P450 metabolism, glucuronide conjugation, and urinary excretion of glucuronidated metabolites represent the primary route of nevirapine biotransformation and elimination in humans. Only a small fraction (less than 5%) of the radioactivity in urine (representing less than 3% of the total dose) was made up of parent compound; therefore, renal excretion plays a minor role in elimination of the parent compound.



Nevirapine is an inducer of hepatic cytochrome P450 (CYP) metabolic enzymes 3A and 2B6. Nevirapine induces CYP3A and CYP2B6 by approximately 20 to 25%, as indicated by erythromycin breath test results and urine metabolites. Autoinduction of CYP3A and CYP2B6 mediated metabolism leads to an approximately 1.5- to 2-­fold increase in the apparent oral clearance of nevirapine as treatment continues from a single dose to two-to-four weeks of dosing with 200 to 400 mg per day of immediate-release nevirapine. Autoinduction also results in a corresponding decrease in the terminal phase half-life of nevirapine in plasma, from approximately 45 hours (single dose) to approximately 25 to 30 hours following multiple dosing with 200 to 400 mg per day.



Specific Populations



Renal Impairment



HIV-1 seronegative adults with mild (CrCl 50 to 79 mL per min; n=7), moderate (CrCl 30 to 49 mL per min; n=6), or severe (CrCl less than 30 mL per min; n=4) renal impairment received a single 200 mg dose of immediate-release nevirapine in a pharmacokinetic trial. These subjects did not require dialysis. The trial included six additional subjects with renal failure requiring dialysis.



In subjects with renal impairment (mild, moderate or severe), there were no significant changes in the pharmacokinetics of nevirapine. However, subjects requiring dialysis exhibited a 44% reduction in nevirapine AUC over a one-week exposure period. There was also evidence of accumulation of nevirapine hydroxy-metabolites in plasma in subjects requiring dialysis. An additional 200 mg dose of immediate-release nevirapine following each dialysis treatment is indicated [see Dosage and Administration (2.5) and Use in Specific Populations (8.6)]. Nevirapine extended-release tablets have not been studied in patients with renal dysfunction.



Hepatic Impairment



In a steady-state trial comparing 46 subjects with mild (n=17; expansion of some portal areas; Ishak Score 1 to 2), moderate (n=20; expansion of most portal areas with occasional portal-to-portal and portal-to-central bridging; Ishak Score 3 to 4), or severe (n=9; marked bridging with occasional cirrhosis without decompensation  indicating Child-Pugh A; Ishak Score 5 to 6) fibrosis as a measure of hepatic impairment, the multiple dose pharmacokinetic disposition of nevirapine and its five  oxidative metabolites were not altered. However, approximately 15% of these subjects with hepatic fibrosis had nevirapine trough concentrations above 9,000 mcg per mL (2-fold the usual mean trough). Therefore, patients with hepatic impairment should be monitored carefully for evidence of drug-induced toxicity [see Warnings and Precautions (5.1)]. The subjects studied were receiving antiretroviral therapy containing immediate-release nevirapine 200 mg twice daily for at least 6 weeks prior to pharmacokinetic sampling, with a median duration of therapy of 3.4 years.



In a pharmacokinetic trial where HIV-1 negative cirrhotic subjects with mild (Child-Pugh A; n=6) or moderate (Child-Pugh B; n=4) hepatic impairment received a single 200 mg dose of immediate-release nevirapine, a significant increase in the AUC of nevirapine was observed in one subject with Child-Pugh B and ascites suggesting that patients with worsening hepatic function and ascites may be at risk of accumulating nevirapine in the systemic circulation. Because nevirapine induces its own metabolism with multiple dosing, this single-dose trial may not reflect the impact of hepatic impairment on multiple-dose pharmacokinetics.



Do not administer nevirapine to patients with moderate or severe (Child-Pugh Class B or C, respectively) hepatic impairment [see Contraindications (4), Warnings and Precautions (5.1), and Use in Specific Populations (8.7)]. Nevirapine extended-release tablets have not been evaluated in patients with hepatic impairment.



Gender



In the multinational 2NN trial of immediate-release nevirapine, a population pharmacokinetic substudy of 1077 subjects was performed that included 391 females. Female subjects showed a 13.8% lower clearance of nevirapine than did men. Since neither body weight nor Body Mass Index (BMI) had an influence on the clearance of nevirapine, the effect of gender cannot solely be explained by body size.



The effects of gender on the pharmacokinetics of nevirapine extended-release tablets have been investigated in Trial 1100.1486. Female subjects tend to have higher (approximately 20­ to 30%) trough concentrations in both nevirapine extended-release tablets and immediate-release nevirapine treatment groups.



Race



An evaluation of nevirapine plasma concentrations (pooled data from several clinical trials) from HIV-1-infected subjects (27 Black, 24 Hispanic, 189 Caucasian) revealed no marked difference in nevirapine steady-state trough concentrations (median Cminss = 4.7 mcg per mL Black, 3.8 mcg per mL Hispanic, 4.3 mcg per mL Caucasian) with long-term treatment with immediate-release nevirapine at 400 mg per day. However, the pharmacokinetics of nevirapine have not been evaluated specifically for the effects of ethnicity.



Black subjects (n=80/group) in Trial 1100.1486 showed approximately 30% to 35% higher trough concentrations than Caucasian subjects (250 to 325 subjects/group) in both immediate-release nevirapine and nevirapine extended-release tablets treatment groups over 96 weeks of treatment at 400 mg per day.



Geriatric Patients



Nevirapine pharmacokinetics in HIV-1-infected adults do not appear to change with age (range 18 to 68 years); however, nevirapine has not been extensively evaluated in patients beyond the age of 65 years [see Use in Specific Populations (8.5)].



Pediatric Patients



The pharmacokinetics of nevirapine extended-release tablets were assessed in HIV-1 infected children 3 to less than 18 years of age. Children enrolled received weight or body surface area dose-adjusted immediate-release nevirapine in combination with other antiretrovirals for a minimum of 18 weeks and then were switched to nevirapine extended-release tablets in combination with other antiretrovirals for 10 days, after which steady-state pharmacokinetic parameters were determined.



Overall, the mean systemic nevirapine exposures in children 6 to less than 18 years of age following administration of nevirapine extended-release tablets and immediate-release nevirapine were similar. Based on intensive PK data (N=17), the observed geometric mean ratios of nevirapine extended-release tablets to immediate-release nevirapine were approximately 97% for Cmin,ss and 94% for AUCss with 90% confidence intervals within 80% to 125%; the ratio for Cmax,ss was lower and consistent with a once daily extended-release dosage form.



Trial 1100.1518 did not provide sufficient pharmacokinetic data for children 3 to less than 6 years of age to support the use of nevirapine extended-release tablets in this age group.



Drug Interactions [see Drug Interactions (7)]



Nevirapine induces hepatic cytochrome P450 metabolic isoenzymes 3A and 2B6. Co-administration of nevirapine extended-release tablets and drugs primarily metabolized by CYP3A or CYP2B6 may result in decreased plasma concentrations of these drugs and attenuate their therapeutic effects.



While primarily an inducer of cytochrome P450 3A and 2B6 enzymes, nevirapine may also inhibit this system. Among human hepatic cytochrome P450s, nevirapine was capable in vitro of inhibiting the 10-hydroxylation of (R)-warfarin (CYP3A). The estimated Ki for the inhibition of CYP3A was 270 micromolar, a concentration that is unlikely to be achieved in patients as the therapeutic range is less than 25 micromolar. Therefore, nevirapine may have minimal inhibitory effect on other substrates of CYP3A.



Nevirapine does not appear to affect the plasma concentrations of drugs that are substrates of other CYP450 enzyme systems, such as 1A2, 2D6, 2A6, 2E1, 2C9, or 2C19.

Table 4 (see below) contains the results of drug interaction trials performed with immediate-release nevirapine and other drugs likely to be co-administered. The effects of nevirapine on the AUC, Cmax, and Cmin of co-administered drugs are summarized. Results of drug interaction studies with immediate-release nevirapine are expected to also apply to nevirapine extended-release tablets.

Because of the design of the drug interaction trials (addition of 28 days of nevirapine therapy to existing HIV-1 therapy), the effect of the concomitant drug on plasma nevirapine steady-state concentrations was estimated by comparison to historical controls.



Administration of rifampin had a clinically significant effect on nevirapine pharmacokinetics, decreasing AUC and Cmax by greater than 50%. Administration of fluconazole resulted in an approximate 100% increase in nevirapine exposure, based on a comparison to historic data [see Drug Interactions (7)]. The effect of other drugs listed in Table 4 on nevirapine pharmacokinetics was not significant. No significant interaction was observed when tipranavir was co-administered with low-dose ritonavir and nevirapine.

12.4 Microbiology

Mechanism of Action



Nevirapine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1. Nevirapine binds directly to reverse transcriptase (RT) and blocks the RNA-dependent and DNA-dependent DNA polymerase activities by causing a disruption of the enzyme's catalytic site. The activity of nevirapine does not compete with template or nucleoside triphosphates. HIV-2 RT and eukaryotic DNA polymerases (such as human DNA polymerases α, ß, γ, or δ) are not inhibited by nevirapine.



Antiviral Activity



The antiviral activity of nevirapine has been measured in a variety of cell lines including peripheral blood mononuclear cells, monocyte-derived macrophages, and lymphoblastoid cell lines. In an assay using human embryonic kidney 293 cells, the median EC50 value (50% inhibitory concentration) of nevirapine was 90 nM against a panel of 2923 wild-type isolates of HIV-1 that were primarily (93%) clade B clinical isolates from the United States. The 99th percentile EC50 value was 470 nM in this trial. The median EC50 value was 63 nM (range 14 to 302 nM, n=29) against clinical isolates of HIV-1 clades A, B, C, D, F, G, and H, and circulating recombinant forms CRF01_AE, CRF02_AG and CRF12_BF. Nevirapine had no antiviral activity in cell culture against group O HIV-1 isolates (n=3) or HIV-2 isolates (n=3) replicating in cord blood mononuclear cells. Nevirapine in combination with efavirenz exhibited strong antagonistic anti-HIV-1 activity in cell culture and was additive to antagonistic with the protease inhibitor ritonavir or the fusion inhibitor enfuvirtide. The anti-HIV-1 activity of nevirapine was not antagonistic in combination with the NRTIs abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir and zidovudine, and the protease inhibitors amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, saquinavir and tipranavir. The anti-HIV-1 activity of nevirapine was antagonized by the anti-HBV drug adefovir and by the anti-HCV drug ribavirin in cell culture.



Resistance



HIV-1 isolates with reduced susceptibility (100- to 250-fold) to nevirapine emerge in cell culture. Genotypic analysis showed mutations in the HIV-1 RT gene encoding Y181C and/or V106A substitutions depending upon the virus strain and cell line employed. Time to emergence of nevirapine resistance in cell culture was not altered when selection included nevirapine in combination with several other NNRTIs.



Phenotypic and genotypic changes in HIV-1 isolates from treatment-naïve subjects receiving either nevirapine (n=24) or nevirapine and zidovudine (n=14) were monitored in Phase 1 and 2 trials ranging from 1 to 12 weeks or longer. After 1 week of nevirapine monotherapy, isolates from 3/3 subjects had decreased susceptibility to nevirapine in cell culture. One or more of the RT mutations resulting in amino acid substitutions K103N, V106A, V108I, Y181C, Y188C, and G190A were detected in HIV-1 isolates from some subjects as early as 2 weeks after therapy initiation. By week eight of nevirapine monotherapy, 100% of the subjects tested (n=24) had HIV-1 isolates with a greater than 100-fold decrease in susceptibility to nevirapine in cell culture compared to baseline and had one or more of the nevirapine RT resistance-associated substitutions. Nineteen (80%) of these subjects had isolates with Y181C substitutions regardless of dose.



Genotypic analysis of isolates from antiretroviral-naïve subjects experiencing virologic failure (n=71) receiving nevirapine once daily (n=25) or twice daily (n=46) in combination with lamivudine and stavudine (trial 2NN) for 48 weeks showed that isolates from 8/25 and 23/46 subjects, respectively, contained one or more of the following NNRTI resistance-associated substitutions: Y181C, K101E, G190A/S, K103N, V106A/M, V108I, Y188C/L, A98G, F227L, and M230L.



For trial 1100.1486, genotypic analysis was performed for baseline and on-therapy isolates from 23 and 34 subjects who experienced virologic failure in the nevirapine extended-release tablets and immediate-release nevirapine treatment group, respectively. Nevirapine resistance-associated substitutions developed in the on-therapy isolates of 78% (18/23) of the subjects who had virologic failures in the nevirapine extended-release tablets treatment group and 88% (30/34) of the subjects in the immediate-release nevirapine treatment group, respectively. The Y181C nevirapine resistance-associated substitution was found alone or in combination with other nevirapine resistance-associated substitutions (K101E, K103N, V106A, V108I, V179D/E/I, Y188 C/F/H/L/N, G190A, P225H, F227L, M230L) in isolates from 14 subjects failing nevirapine extended-release tablets treatment and 25 subjects failing immediate-release nevirapine treatment. On-therapy isolates from 1 subject in nevirapine extended-release tablets treatment group developed a novel amino acid substitution Y181I and isolates from another subject in the immediate-release nevirapine treatment group developed a novel amino acid substitution Y188N. Phenotypic analysis showed that Y188N and Y181I substitutions conferred 103- and 22-fold reductions in susceptibility to nevirapine, respectively.



Cross-resistance



Rapid emergence of HIV-1 strains which are cross-resistant to NNRTIs has been observed in cell culture. Nevirapine-resistant HIV-1 isolates were cross-resistant to the NNRTIs efavirenz and etravirine. The Y188N conferred a 7-fold reduction in susceptibility to efavirenz but showed no decrease in susceptibility to etravirine. Similarly, the Y181I substitution reduced susceptibility to etravirine 8-fold, but did not reduce susceptibility to efavirenz. However, nevirapine-resistant isolates were susceptible to the NRTI ZDV. Similarly, ZDV-resistant isolates were susceptible to nevirapine in cell culture.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis



Long-term carcinogenicity studies in mice and rats were carried out with nevirapine. Mice were dosed with 0, 50, 375 or 750 mg/kg/day for two years. Hepatocellular adenomas and carcinomas were increased at all doses in males and at the two high doses in females. In studies in which rats were administered nevirapine at doses of 0, 3.5, 17.5 or 35 mg/kg/day for two years, an increase in hepatocellular adenomas was seen in males at all doses and in females at the high dose. The systemic exposure (based on AUCs) at all doses in the two animal studies was lower than that measured in humans at the 200 mg twice daily dose of immediate-release nevirapine. The mechanism of the carcinogenic potential is unknown.



Mutagenesis



However, in genetic toxicology assays, nevirapine showed no evidence of mutagenic or clastogenic activity in a battery of in vitro and in vivo studies. These included microbial assays for gene mutation (Ames: Salmonella strains and E. coli), mammalian cell gene mutation assay (CHO/HGPRT), cytogenetic assays using a Chinese hamster ovary cell line and a mouse bone marrow micronucleus assay following oral administration. Given the lack of genotoxic activity of nevirapine, the relevance to humans of hepatocellular neoplasms in nevirapine-treated mice and rats is not known.



Impairment of Fertility



In reproductive toxicology studies, evidence of impaired fertility was seen in female rats at doses providing systemic exposure, based on AUC, approximately equivalent to that provided with the recommended clinical dose.

13.2 Animal Toxicology and/or Pharmacology

Animal studies have shown that nevirapine is widely distributed to nearly all tissues and readily crosses the blood-brain barrier.

14.1 Adult Patients

The clinical efficacy of nevirapine extended-release tablets is based on 96-week data from an ongoing, randomized, double-blind, double-dummy Phase 3 trial (Trial 1100.1486, VERxVE) in treatment-naïve subjects and on 48-week data in an ongoing, randomized, open-label trial in subjects who switched from immediate-release nevirapine tablets administered twice daily to nevirapine extended-release tablets administered once daily (Trial 1100.1526, TRANxITION).



Treatment-naïve Subjects



Trial 1100.1486 (VERxVE) is a Phase 3 trial in which treatment-naïve subjects received immediate-release nevirapine 200 mg once daily for 14 days and then were randomized to receive either immediate-release nevirapine 200 mg twice daily or nevirapine extended-release tablets 400 mg once daily. All subjects received tenofovir + emtricitabine as background therapy. Randomization was stratified by screening HIV-1 RNA level (less than or equal to 100,000 copies per mL and greater than 100,000 copies per mL). Subject demographic and baseline disease characteristics were balanced between the two treatment groups. With respect to demographics: 85% of the subjects were male, 75% were white, 20% were black, and approximately 29% were from North America. With respect to baseline disease characteristics: mean viral load was 4.7 log10 copies per mL, mean CD4+ cell count was 228 cells/mm3 and 73% of subjects had clade B HIV-1 subtype. Approximately two-thirds of the subjects had a baseline HIV-RNA level of less than or equal to 100,000 copies per mL.



Table 5 describes week 96 outcomes in the Trial 1100.1486 (VERxVE). These outcomes include all subjects who were randomized after the 14 day lead-in with immediate-release nevirapine and received at least one dose of blinded study medication.

At 96 weeks, mean change from baseline in CD4+ cell count adjusting for baseline HIV-1 viral load stratum was 222 cells/mm3 and 244 cells/mm3 for the groups receiving immediate-release nevirapine and nevirapine extended-release tablets, respectively.



Subjects Switching from Immediate-release Nevirapine to Nevirapine Extended-Release Tablets 



Trial 1100.1526 (TRANxITION) is a Phase 3 trial to evaluate safety and antiviral activity of switching from immediate-release nevirapine to nevirapine extended-release tablets. In this open-label trial, 443 subjects already on an antiviral regimen containing immediate-release nevirapine 200 mg twice daily with HIV-1 RNA less than 50 copies per mL were randomized in a 2:1 ratio to nevirapine extended-release tablets 400 mg once daily or immediate-release nevirapine 200 mg twice daily. Approximately half of the subjects had tenofovir+emtricitabine as their background therapy, with the remaining subjects receiving abacavir sulfate+lamivudine or zidovudine+lamivudine. Approximately half of the subjects had at least 3 years of exposure to immediate-release nevirapine prior to entering the trial.



At 48 weeks after randomization in Trial 1100.1526, 91% of subjects receiving immediate-release nevirapine 200 mg twice daily and 93% of subjects receiving nevirapine extended-release tablets 400 mg once daily continued to have HIV-1 RNA less than 50 copies per mL.

14.2 Pediatric Patients

Trial 1100.1518 was an open-label, multiple-dose, non-randomized, crossover trial performed in 85 HIV-1 infected pediatric subjects 3 to less than 18 years of age who had received at least 18 weeks of immediate-release nevirapine and had plasma HIV-1 RNA less than 50 copies per mL prior to trial enrollment. Subjects were stratified according to age (3 to less than 6 years, 6 to less than 12 years, and 12 to less than 18 years). Following a 10-day period with immediate-release nevirapine, subjects were treated with nevirapine extended-release tablets once daily in combination with other antiretrovirals for 10 days, after which steady-state pharmacokinetic parameters were determined. Forty of the 80 subjects who completed the initial part of the study were enrolled in an optional extension phase of the trial which evaluated the safety and antiviral activity of nevirapine extended-release tablets through a minimum of 24 weeks of treatment. Zidovudine or stavudine plus lamivudine were the most commonly used background therapies in subjects who entered the optional extension phase.



Baseline demographics included: 55% of the subjects were female, 93% were black, 7% were white, and approximately 84% were from Africa. Subjects had a median baseline CD4+ cell count of 925 cells/mm3 (range 207 to 2057 cells/mm3).



Of the 40 subjects who entered the treatment extension phase, 39 completed at least 24 weeks of treatment and one subject discontinued prematurely due to an adverse reaction. After 24 weeks or more of treatment with nevirapine extended-release tablets, all 39 subjects continued to have plasma HIV-1 RNA less than 50 copies per mL. Median CD4+ cell counts for the 3 to less than 6 year, 6 to less than 12 year, and 12 to less than 18 year age groups were 1113 cells/mm3, 853 cells/mm3, and 682 cells/mm3, respectively. These CD4+ cell counts were similar to those observed at baseline.