| Pharmacotherapeutic group: Antivirals for systemic use, non-nucleoside reverse transcriptase inhibitors, ATC code J05AG01. Mechanism of action Nevirapine is a NNRTI of HIV-1. Nevirapine is a non-competitive inhibitor of the HIV-1 reverse transcriptase, but it does not have a biologically significant inhibitory effect on the HIV-2 reverse transcriptase or on eukaryotic DNA polymerases α, β, γ, or δ.Antiviral activity in vitroNevirapine had a median EC50 value (50% inhibitory concentration) of 63 nM against a panel of group M HIV-1 isolates from clades A, B, C, D, F, G, and H, and circulating recombinant forms (CRF), CRF01_AE, CRF02_AG and CRF12_BF replicating in human embryonic kidney 293 cells. In a panel of 2,923 predominantly subtype B HIV-1 clinical isolates, the mean EC50 value was 90nM. Similar EC50 values are obtained when the antiviral activity of nevirapine is measured in peripheral blood mononuclear cells, monocyte derived macrophages or lymphoblastoid cell line. Nevirapine had no antiviral activity in cell culture against group O HIV-1 isolates or HIV-2 isolates.Nevirapine in combination with efavirenz exhibited a strong antagonistic anti-HIV-1 activity in vitro (see section 4.5) and was additive to antagonistic with the protease inhibitor ritonavir or the fusion inhibitor enfuvirtide.Nevirapine exhibited additive to synergistic anti-HIV-1 activity in combination with the protease inhibitors amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, saquinavir and tipranavir, and the NRTIs abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir and zidovudine. The anti-HIV-1 activity of nevirapine was antagonized by the anti-HBV medicinal product adefovir and by the anti-HCV medicinal product ribavirin in vitro.Resistance HIV-1 isolates with reduced susceptibility (100-250-fold) to nevirapine emerge in cell culture. Genotypic analysis showed mutations in the HIV-1 RT gene Y181C and/or V106A 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 patients receiving either nevirapine (n=24) or nevirapine and ZDV (n=14) were monitored in Phase I/II studies over 1 to 12 weeks. After 1 week of nevirapine monotherapy, isolates from 3/3 patients 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 patients as early as 2 weeks after therapy initiation. By week eight of nevirapine monotherapy, 100% of the patients tested (n=24) had HIV-1 isolates with a >100-fold decrease in susceptibility to nevirapine in cell culture compared to baseline, and had one or more of the nevirapine-associated RT resistance mutations. Nineteen of these patients (80%) had isolates with Y181C substitutions regardless of dose.Genotypic analysis of isolates from antiretroviral naïve patients experiencing virologic failure (n=71) receiving nevirapine once daily (n=25) or twice daily (n=46) in combination with lamivudine and stavudine for 48 weeks showed that isolates from 8/25 and 23/46 patients, 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.Genotypic analysis was performed on isolates from 86 antiretroviral naïve patients who discontinued the VERxVE study (1100.1486) after experiencing virologic failure (rebound, partial response) or due to an adverse event or who had transient increase in viral load during the course of the study. The analysis of these samples of patients receiving Viramune immediate-release twice daily or Viramune prolonged-release once daily in combination with tenofovir and emtricitabine showed that isolates from 50 patients contained resistance mutations expected with a nevirapine-based regimen. Of these 50 patients, 28 developed resistance to efavirenz and 39 developed resistance to etravirine (the most frequently emergent resistance mutation being Y181C). There were no differences based on the formulation taken (immediate-release twice daily or prolonged-release once daily).The observed mutations at failure were those expected with a nevirapine-based regimen. Two new substitutions on codons previously associated with nevirapine resistance were observed: one patient with Y181I in the Viramune prolonged-release group and one patient with Y188N in the Viramune immediate-release group; resistance to nevirapine was confirmed by phenotype.Cross-resistance Rapid emergence of HIV-strains which are cross-resistant to NNRTIs has been observed in vitro. Cross resistance to delavirdine and efavirenz is expected after virologic failure with nevirapine. Depending on resistance testing results, an etravirine-containing regimen may be used subsequently. Cross-resistance between nevirapine and either HIV protease inhibitors, HIV integrase inhibitors or HIV entry inhibitors is unlikely because the enzyme targets involved are different. Similarly the potential for cross-resistance between nevirapine and NRTIs is low because the molecules have different binding sites on the reverse transcriptase.Clinical results Viramune has been evaluated in both treatment-naïve and treatment-experienced patients. Studies in treatment-naïve patients 2NN study The double non-nucleoside study 2 NN was a randomised, open-label, multicentre prospective study comparing the NNRTIs nevirapine, efavirenz and both medicinal products given together. 1216 antiretroviral-therapy naïve patients with plasma HIV-1 RNA > 5000 copies/ml at baseline were assigned to Viramune 400 mg once daily, Viramune 200 mg twice daily, efavirenz 600 mg once daily, or Viramune (400 mg) and efavirenz (800 mg) once daily, plus stavudine and lamivudine for 48 weeks. The primary endpoint, treatment failure, was defined as less than 1 log10 decline in plasma HIV-1 RNA in the first 12 weeks, or two consecutive measurements of more than 50 copies/ ml from week 24 onwards, or disease progression (new Centers for Disease Control and Prevention grade C event or death), or change of allocated treatment. Median age was 34 years and about 64% were male patients, median CD4 cell count was 170 and 190 cells per mm3 in the Viramune twice daily and efavirenz groups, respectively. There were no significant differences in demographic and baseline characteristics between the treatment groups. The predetermined primary efficacy comparison was between the Viramune twice daily and the efavirenz treatment groups. Details of the primary efficacy comparison are given in table 1.Table 1: Number of patients with treatment failure, components of treatment failure, and number of patients with plasma HIV-RNA concentration < 50 c/ml, at week 48 (Intention-To-Treat (ITT) Analysis).| | Viramune 200 mg twice daily(n = 387) | Efavirenz 600 mg once daily(n = 400) | | Treatment failure on or before week 48, % (95% IC) | 43.7% (38.7-48.8)
| 37.8% (33.0-42.7)
| | Components of failure (%)Virological
Progression
Change of treatment
Permanent change of NNRTI (n) Temporary discontinuation of NNRTI (n)
Additional antiretroviral medicinal products (n)
Non-allowable change of NNRTI (n)
Never started ART* (n)
| 18.9%
2.8%
22.0%
61
13
1
1
9
| 15.3%
2.5%
20.0%
51
8
1
1
19
| | Plasma HIV-1 RNA concentration <50 c/ml at 48 weeks, %(95% IC) | 65.4% (60.4-70.1)
| 70.0% (65.2-74.5)
| * ART = antiretroviral therapy Although, overall, treatment failure was numerically lower in the efavirenz group than in the nevirapine-only groups, the findings of this study show no evidence that efavirenz is superior to nevirapine twice daily in terms of treatment failure. However, equivalence within the 10% limits of these treatment groups was not shown even though the study was adequately powered for such an analysis. The nevirapine twice daily regimen and the efavirenz regimen were not significantly different (p= 0.091) in terms of efficacy as measured by incidence of treatment failure. There was also no significant difference between Viramune twice daily and efavirenz regarding any components of treatment failure including virological failure.The simultaneous use of nevirapine (400 mg) plus efavirenz (800 mg) was associated with the highest frequency of clinical adverse events and with the highest rate of treatment failure (53.1%). As the regimen of nevirapine plus efavirenz did not have additional efficacy and caused more adverse events than each medicinal product separately, this regimen is not recommended.Twenty per cent of patients assigned to nevirapine twice daily and 18% of patients assigned to efavirenz had at least one grade 3 or 4 clinical adverse event. Clinical hepatitis reported as clinical adverse event occurred in 10 (2.6%) and 2 (0.5%) patients in the nevirapine twice daily and efavirenz groups respectively. The proportion of patients with at least one grade 3 or 4 liver-associated laboratory toxicity was 8.3% for nevirapine twice daily and 4.5% for efavirenz. Of the patients with grade 3 or 4 liver-associated laboratory toxicity, the proportions coinfected with hepatitis B or hepatitis C virus were 6.7% and 20.0% in the nevirapine twice daily group, 5.6% and 11.1% in the efavirenz group.2NN Three-year follow-up-study This is a retrospective multicentre study comparing the 3-year antiviral efficacy of Viramune and efavirenz in combination with stavudine and lamivudine in 2NN patients from week 49 to week 144. Patients who participated in the 2NN study and were still under active follow-up at week 48 when the study closed and were still being treated at the study clinic, were asked to participate in this study. Primary study endpoints (percentage of patients with treatment failures) and secondary study endpoints as well as backbone therapy were similar to the original 2NN study. Table 2 shows the main efficacy results of this study.Table 2: Number of patients with treatment failure, components of treatment failure, and number of patients with plasma HIV-RNA concentration < 400 copies/ml, between week 49 to 144 (ITT analysis).| | Viramune 200 mg twice daily (n=224) | Efavirenz 600 mg once daily (n=223) | | Treatment failure (%)
| 35.7
| 35.0
| | Virologic failure (>400 c/ml) (%)
| 5.8
| 4.9
| | pVL <400 c/ml at week 144 (%)
| 87.2
| 87.4
| | CD4 increase (cells/mm3)
| +135
| +130
| | Disease progression / death (%)
| 5.8
| 6.3
| A durable response to Viramune for at least three years was documented in this study. Equivalence within a 10% range was demonstrated between Viramune 200 mg twice daily and efavirenz with respect to treatment failure. Both, the primary (p = 0.92) and secondary endpoints showed no statistically significant differences between efavirenz and Viramune 200 mg twice daily.Studies in treatment-experienced patients NEFA study The NEFA study is a controlled prospective randomised study which evaluated treatment options for patients who switch from protease inhibitor (PI) based regimen with undetectable load to either Viramune, efavirenz or abacavir.The study randomly assigned 460 adults who were taking two nucleoside reverse-transcriptase inhibitors and at least one PI and whose plasma HIV-1 RNA levels had been less than 200 c/ml for at least the previous six months to switch from the PI to Viramune (155 patients), efavirenz (156), or abacavir (149).The primary study endpoint was death, progression to the acquired immunodeficiency syndrome, or an increase in HIV-1 RNA levels to 200 copies or more per millilitre. The main results regarding the primary endpoint are given in table 3.Table 3: Outcome of Therapy 12 months after switch from PI based therapy | | Viramune (n=155) | Efavirenz(n=156) | Abacavir(n=149) | | Number of patients
| | Death
| 1
| 2
| 1
| | Progression to AIDS
| 0
| 0
| 2
| | Virologic failure
While taking medicinal product
After switching medicinal product
| 14
8
6
| 7
5
2
| 16
16
0
| | Lost to follow-up
| 3
| 6
| 8
| | Switched medicinal product without virologic failure
| 20
| 29
| 9
| | Response; still taking medicinal product at 12 months
| 117
| 112
| 113
| At 12 months, the KaplanMeier estimates of the likelihood of reaching the endpoint were 10 % in the Viramune group, 6 % in the efavirenz group, and 13 percent in the abacavir group (P=0.10 according to an intention-to-treat analysis). The overall incidence of adverse events was significantly lower (61 patients, or 41%) in the abacavir group than in the nevirapine group (83 patients, or 54%) or the efavirenz group (89 patients, or 57%). Significantly fewer patients in the abacavir group (9 patients, or 6%) than in the nevirapine group (26 patients, or 17%) or the efavirenz group (27 patients, or 17%) discontinued the medicinal product because of adverse events (see table below).| Number of patients who had one or more adverse events* | | Adverse Event
| Nevirapine
(N=155)
| Efavirenz
(N=156)
| Abacavir
(N=149)
| | | Any adverse event
| Grade 3 or 4 adverse event
| Adverse event leading to discontinuation
| Any adverse event
| Grade 3 or 4 adverse event
| Adverse event leading to discontinuation
| Any adverse event
| Grade 3 or 4 adverse event
| Adverse event leading to discontinuation
| | | Number of patients (percent) | | Clinical | | | | | | | | | | | - Neuropsychiatric
| 11
| 6
| 6
| 48
| 22
| 19
| 14
| 1
| 0
| | - Cutaneous
| 20
| 13
| 12
| 11
| 3
| 3
| 7
| 0
| 0
| | - Gastrointestinal
| 6
| 2
| 0
| 8
| 4
| 4
| 12
| 2
| 1
| | - Systemic**
| 7
| 1
| 1
| 5
| 2
| 0
| 10
| 8
| 8
| | - Other
| 25
| 8
| 1
| 11
| 5
| 1
| 12
| 3
| 0
| | | | | | | | | | | | | Laboratory | | | | | | | | | | | - Increased aminotransferase levels
| 12
| 6
| 4
| 4
| 1
| 0
| 5
| 1
| 0
| | - Hyperglycemia
| 2
| 2
| 2
| 2
| 2
| 0
| 1
| 1
| 0
| | | | | | | | | | | | | Total | 83 (54)***
| 38
| 26 (17)****
| 89 (57)***
| 39
| 27 (17)****
| 61 (41)***
| 16
| 9 (6)****
|
| *
| A grade 3 event was defined as severe, and a grade 4 event as life-threatening
| | **
| Systemic adverse events included hypersensitivity reactions
| | ***
| P=0.02 by the chi-square test
| | ****
| P=0.01 by the chi-square test
|
Clinical studies with prolonged-release tablets The clinical efficacy of Viramune prolonged-release is based on 48-week data from an ongoing, randomised, double-blind, double-dummy phase 3 study (VERxVE study 1100.1486) in treatment-naïve patients and on 24-week data from an ongoing, randomised, open-label study in patients who transitioned from Viramune immediate-release tablets administered twice daily to Viramune prolonged-release tablets administered once daily (TRANxITION study 1100.1526). Treatment-naïve patients VERxVE (study 1100.1486) is a phase 3 study in which treatment-naïve patients received Viramune 200 mg immediate-release once daily for 14 days and then were randomised to receive either Viramune 200 mg immediate-release twice daily or Viramune 400 mg prolonged-release once daily. All patients received tenofovir + emtricitabine as background therapy. Randomisation was stratified by screening HIV-1 RNA level (<100,000 copies/ml and >100,000 copies/ml). Selected demographic and baseline disease characteristics are displayed in Table 4.Table 4: Demographic and Baseline Disease Characteristics in study 1100.1486 | | Viramune immediate-release | Viramune prolonged-release | | | n=508*
| n=505
| | Gender | | - Male
| 85%
| 85%
| | - Female
| 15%
| 15%
| | Race | | - White
| 74%
| 77%
| | - Black
| 22%
| 19%
| | - Asian
| 3%
| 3%
| | - Other** | 1%
| 2%
| | Region | | - North America
| 30%
| 28%
| | - Europe
| 50%
| 51%
| | - Latin America
| 10%
| 12%
| | - Africa
| 11%
| 10%
| | Baseline Plasma HIV-1 RNA (log10 copies/ml) | | - Mean (SD)
| 4.7 (0.6)
| 4.7 (0.7)
| | - <100,000
| 66%
| 67%
| | - >100,000
| 34%
| 33%
| | Baseline CD4 count (cells/mm3) | | - Mean (SD)
| 228 (86)
| 230 (81)
| | HIV-1 subtype | | - B
| 71%
| 75%
| | - Non-B
| 29%
| 24%
| * Includes 2 patients who were randomised but never received blinded medicinal products. ** Includes American Indians/Alaska natives and Hawaiian/Pacific islanders.Table 5 describes week 48 outcomes in the VERxVE study (1100.1486). These outcomes include all patients who were randomised after the 14 day lead-in with Viramune immediate-release and received at least one dose of blinded medicinal product.Table 5: Outcomes at week 48 in study 1100.1486* | | Viramune immediate-releasen =506 | Viramune prolonged-releasen=505 | | Virologic responder (HIV-1 RNA <50 copies/ml)
| 75.9%
| 81.0%
| | Virologic failure
| 5.9%
| 3.2%
| | - Never suppressed through week 48
| 2.6%
| 1.0%
| | - Rebound
| 3.4%
| 2.2%
| | Discontinued medicinal product prior to week 48
| 18.2%
| 15.8%
| | - Death
| 0.6%
| 0.2%
| | - Adverse events
| 8.3%
| 6.3%
| | - Other**
| 9.3%
| 9.4%
| * Includes patients who received at least one dose of blinded medicinal product after randomisation. Patients who discontinued treatment during the lead-in period are excluded.** Includes lost to follow-up, consent withdrawn, noncompliance, lack of efficacy, pregnancy, and other.At week 48, mean change from baseline in CD4 cell count was 184 cells/mm3 and 197 cells/mm3 for the groups receiving Viramune immediate-release and Viramune prolonged-release respectively.Table 6 shows outcomes at 48-weeks in study 1100.1486 (after randomization) by baseline viral load.Table 6: Outcomes at 48 weeks in study 1100.1486 by baseline viral load* | | Number with response/total number (%) | Difference in %(95% CI) | | | Viramune immediate-release | Viramune prolonged-release | | Baseline HIV−1 viral load stratum (copies/ml)
| | | | | - < 100,000
| 240/303 (79.2%)
| 267/311 (85.0%)
| 6.6 (0.7, 12.6)
| | - >100,000
| 144/203 (70.9%)
| 142/194 (73.2%)
| 2.3 (−6.6, 11.1)
| | Total | 384/506 (75.9%) | 409/505 (81.0%) | 4.9 (−0.1, 10.0)** | * Includes patients who received at least one dose of blinded medicinal product after randomisation. Patients who discontinued treatment during the lead-in period are excluded.** Based on Cochran's statistic with continuity correction for the variance calculationThe overall percentage of treatment responders observed in study 1100.1486 (including lead-in phase), regardless of the formulation is 793/1,068 = 74.3%. The denominator 1,068 includes 55 patients who stopped treatment during the lead in phase and two patients randomized but never treated with randomized dose. The numerator 793 is the number of patients who were treatment responders at 48 weeks (384 from immediate-release and 409 from prolonged-release treatment groups). Lipids, Change from baseline Changes from baseline in fasting lipids are shown in Table 7.Table 7: Summary of lipid laboratory values at baseline (screening) and week 48 - study 1100.1486 | | Viramune immediate-release | Viramune prolonged-release | | | Baseline(mean)n=503 | Week 48(mean)n=407 | Percent change* n=406 | Baseline(mean)n=505 | Week 48(mean)n=419 | Percent change* n=419 | | LDL (mg/dL)
| 98.8
| 110.0
| +9
| 98.3
| 109.5
| +7
| | HDL (mg/dL)
| 38.8
| 52.2
| +32
| 39.0
| 50.0
| +27
| | Total cholesterol. (mg/dL)
| 163.8
| 186.5
| +13
| 163.2
| 183.8
| +11
| | Total cholesterol/HDL
| 4.4
| 3.8
| -14
| 4.4
| 3.9
| -12
| | Triglycerides (mg/dL)
| 131.2
| 124.5
| -9
| 132.8
| 127.5
| -7
| * Percent change is the median of within-patient changes from baseline for patients with both baseline and week 48 values and is not a simple difference of the baseline and week 48 mean values, respectively.Patients switching from Viramune immediate-release to Viramune prolonged-release TRANxITION (study 1100.1526) is a Phase 3 study to evaluate safety and antiviral activity in patients switching from Viramune immediate-release to Viramune prolonged-release. In this open-label study, 443 patients already on an antiviral regimen containing Viramune 200 mg immediate-release twice daily with HIV-1 RNA < 50 copies/ml were randomised in a 2:1 ratio to Viramune 400 mg prolonged-release once daily or Viramune 200 mg immediate-release twice daily. Approximately half of the patients had tenofovir + emtricitabine as their background therapy, with the remaining patients receiving abacavir sulfate + lamivudine or zidovudine + lamivudine. Approximately half of the patients had at least 3 years of prior exposure to Viramune immediate-release prior to entering study 1100.1526. At 24 weeks after randomisation in the TRANxITION study, 92.6% and 93.6% of patients receiving Viramune 200 mg immediate-release twice daily or Viramune 400 mg prolonged-release once daily, respectively, continued to have HIV-1 RNA < 50 copies/ml.Paediatric population Results of a 48-week analysis of the South African study BI 1100.1368 confirmed that the 4/7 mg/kg and 150 mg/m2 nevirapine dose groups were well tolerated and effective in treating antiretroviral naive paediatric patients. A marked improvement in the CD4+ cell percent was observed through Week 48 for both dose groups. Also, both dosing regimens were effective in reducing the viral load. In this 48-week study no unexpected safety findings were observed in either dosing group. | |