Mechanism of Action
Darunavir is an HIV antiviral drug.
Pharmacodynamics
In an open-label, randomized, placebo- and
active-controlled, four-way crossover trial, 40 healthy subjects were
administered supratheraputic doses of darunavir/ritonavir 1600/100 mg once
daily and 800/100 mg twice daily for seven days.
At the mean maximum darunavir concentration of 6599 ng/mL
observed in this study, the mean increase in QTcF was 2.2 ms with a 90%
two-sided confidence interval (CI) of -2.0 to 6.3 ms. When evaluating the
2-sided 90% CI on the time-matched mean changes in QTcF versus placebo control,
the upper bounds of both darunavir/ritonavir groups never exceeded the 10 ms
boundary. In the setting of this trial, darunavir/ritonavir did not appear to
prolong the QTc interval.
Pharmacokinetics
Pharmacokinetics in Adults
General
Darunavir is primarily metabolized by CYP3A. Ritonavir
inhibits CYP3A, thereby increasing the plasma concentrations of darunavir. When
a single dose of PREZISTA 600 mg was given orally in combination with 100 mg
ritonavir twice daily, there was an approximate 14-fold increase in the
systemic exposure of darunavir.
Therefore, PREZISTA should only be used in combination with
100 mg of ritonavir to achieve sufficient exposures of darunavir.
The pharmacokinetics of darunavir, co-administered with low
dose ritonavir (100 mg), has been evaluated in healthy adult volunteers and in
HIV-1-infected subjects. Table 8 displays the population pharmacokinetic
estimates of darunavir after oral administration of PREZISTA/rtv 600/100 mg twice
daily [based on sparse sampling in 285 patients in study TMC114-C214 and 119
patients (integrated data) from Studies TMC114-C202 and TMC114C213] and
PREZISTA/rtv 800/100 mg once daily [based on sparse sampling in 335 patients in
Study TMC114C211] to HIV-1-infected patients.
Table 8: Population Pharmacokinetic Estimates of Darunavir
at PREZISTA/rtv 800/100 mg once daily (Study TMC114-C211, 48 Week Analysis)
and PREZISTA/rtv 600/100 mg twice daily (Study TMC114-C214, 48 Week Analysis
and Integrated data from Studies TMC114-C213 and TMC114-C202, Primary 24-Week
Analysis)
| Parameter |
Study TMC114-C211
PREZISTA/rtv 800/100 mg
once daily
N = 335 |
Study TMC114-C214
PREZISTA/rtv
600/100 mg
twice daily
N = 285 |
Studies TMC114-C213
and TMC114-C202
(integrated data)
PREZISTA/rtv
600/100mg twice daily
N =119 |
| AUC24h (ng•h/mL) * |
| Mean± Standard Deviation |
93026 ± 27050 |
116796 ± 124698 |
124698 ± 32286 |
| Median (Range) |
87854 (45000-219240) |
111632 (64874-355360) |
123336 (67714-212980) |
| C0h (ng/mL) |
| Mean± Standard Deviation |
2282 ± 1168 |
3490 ± 3578 |
3578 ± 1151 |
| Median (Range) |
2041 (368-7242) |
3307 (1517-13198) |
3539 (1255-7368) |
N = number of subjects with data.
*AUC24h is calculated as AUC12h*2 |
Absorption and Bioavailability
Darunavir, co-administered with 100 mg ritonavir twice
daily, was absorbed following oral administration with a Tmax of approximately
2.5-4 hours. The absolute oral bioavailability of a single 600 mg dose of
darunavir alone and after co-administration with 100 mg ritonavir twice daily
was 37% and 82%, respectively. In vivo data suggests that darunavir/ritonavir
is an inhibitor of the p-glycoprotein (p-gp) transporters.
Effects of Food on Oral Absorption
When administered with food, the Cmax and AUC of darunavir, co-administered
with ritonavir, is approximately 30% higher relative to the fasting state. Therefore,
PREZISTA tablets, co-administered with ritonavir, should always be taken with
food. Within the range of meals studied, darunavir exposure is similar. The
total caloric content of the various meals evaluated ranged from 240 Kcal (12
gms fat) to 928 Kcal (56 gms fat).
Distribution
Darunavir is approximately 95% bound to plasma proteins.
Darunavir binds primarily to plasma alpha 1-acid glycoprotein (AAG).
Metabolism
In vitro experiments with human liver microsomes (HLMs)
indicate that darunavir primarily undergoes oxidative metabolism. Darunavir is
extensively metabolized by CYP enzymes, primarily by CYP3A. A mass balance
study in healthy volunteers showed that after a single dose administration of
400 mg 14C-darunavir, co-administered with 100 mg ritonavir, the majority of
the radioactivity in the plasma was due to darunavir. At least 3 oxidative
metabolites of darunavir have been identified in humans; all showed activity
that was at least 90% less than the activity of darunavir against wild-type
HIV.
Elimination
A mass balance study in healthy volunteers showed that after
single dose administration of 400 mg 14C-darunavir, co-administered with 100 mg
ritonavir, approximately 79.5% and 13.9% of the administered dose of
14C-darunavir was recovered in the feces and urine, respectively. Unchanged darunavir
accounted for approximately 41.2% and 7.7% of the administered dose in feces
and urine, respectively. The terminal elimination half-life of darunavir was
approximately 15 hours when co-administered with ritonavir. After intravenous
administration, the clearance of darunavir, administered alone and
co-administered with 100 mg twice daily ritonavir, was 32.8 L/h and 5.9 L/h,
respectively.
Special Populations
Hepatic Impairment
Darunavir is primarily metabolized by the liver. The steady-state pharmacokinetic
parameters of darunavir were similar after multiple dose co-administration of
PREZISTA/rtv 600/100 mg twice daily to subjects with normal hepatic function
(n=16), mild hepatic impairment (Child-Pugh Class A, n=8), and moderate hepatic
impairment (Child-Pugh Class B, n=8). The effect of severe hepatic impairment
on the pharmacokinetics of darunavir has not been evaluated [see DOSAGE
AND ADMINISTRATION and Use in Specific
Populations].
Hepatitis B or Hepatitis C Virus Co-infection
The 48-week analysis of the data from Studies TMC114-C211
and TMC114-C214 in HIV-1-infected subjects indicated that hepatitis B and/or
hepatitis C virus co-infection status had no apparent effect on the exposure of
darunavir.
Renal Impairment
Results from a mass balance study with 14C-darunavir/ritonavir showed that
approximately 7.7% of the administered dose of darunavir is excreted in the
urine as unchanged drug. As darunavir and ritonavir are highly bound to plasma
proteins, it is unlikely that they will be significantly removed by hemodialysis
or peritoneal dialysis. Population pharmacokinetic analysis showed that the
pharmacokinetics of darunavir were not significantly affected in HIV-infected
subjects with moderate renal impairment (CrCL between 30-60 mL/min, n=20). There
are no pharmacokinetic data available in HIV-1-infected patients with severe
renal impairment or end stage renal disease [see Use
in Specific Populations].
Gender
Population pharmacokinetic analysis showed higher mean
darunavir exposure in HIV-infected females compared to males. This difference
is not clinically relevant.
Race
Population pharmacokinetic analysis of darunavir in
HIV-infected subjects indicated that race had no apparent effect on the
exposure to darunavir.
Geriatric Patients
Population pharmacokinetic analysis in HIV-infected subjects showed that darunavir
pharmacokinetics are not considerably different in the age range (18 to 75 years)
evaluated in HIV-infected subjects (n = 12, age ≥ 65) [see Use
in Specific Populations].
Pediatric Patients
The pharmacokinetics of darunavir in combination with ritonavir in 74 antiretroviral
treatment-experienced HIV-1infected pediatric subjects 6 to < 18 years of
age and weighing at least 44 lbs (20 kg) showed that the administered weight-based
dosages resulted in darunavir exposure comparable to that in treatment-experienced
adults receiving PREZISTA/rtv 600/100 mg twice daily [see DOSAGE AND ADMINISTRATION].
Table 9: Population Pharmacokinetic Estimates of Darunavir
Exposure (Study TMC114-C212) Following Administration of Doses in Table 1
| Parameter Median (Range) |
PREZISTA/rtv twice daily
N = 74 |
| AUC24h (ng•h/mL) |
127340 (67054-230720) |
| C0h (ng/mL) |
3888 (1836-7821) |
N = number of subjects with data.
*AUC24h is calculated as AUC12h*2 |
Drug Interactions
[See also CONTRAINDICATIONS, WARNINGS
AND PRECAUTIONS, and DRUG
INTERACTIONS.]
Darunavir co-administered with ritonavir is an inhibitor of
CYP3A and CYP2D6. Co-administration of darunavir and ritonavir with drugs
primarily metabolized by CYP3A and CYP2D6 may result in increased plasma
concentrations of such drugs, which could increase or prolong their therapeutic
effect and adverse events.
Darunavir and ritonavir are metabolized by CYP3A. Drugs that
induce CYP3A activity would be expected to increase the clearance of darunavir
and ritonavir, resulting in lowered plasma concentrations of darunavir and
ritonavir. Co-administration of darunavir and ritonavir and other drugs that
inhibit CYP3A may decrease the clearance of darunavir and ritonavir and may
result in increased plasma concentrations of darunavir and ritonavir.
Drug interaction studies were performed with darunavir and
other drugs likely to be co-administered and some drugs commonly used as probes
for pharmacokinetic interactions. The effects of co-administration of darunavir
on the AUC, Cmax, and Cmin values are summarized in Table 10 (effect of other
drugs on darunavir) and Table 11 (effect of darunavir on other drugs). For
information regarding clinical recommendations, see DRUG INTERACTIONS.
Table 10: Drug Interactions: Pharmacokinetic Parameters for
Darunavir in the Presence of Coadministered Drugs
| Co-Administered Drug |
Dose/Schedule Co-Administered
Drug |
Darunavir/ ritonavir |
N |
PK |
LS Mean Ratio (90%CI) of Co-Administered
Drug Pharmacokinetic Parameters With/Without Darunavir No effect =1.00 |
| Cmax |
AUC |
Cmin |
| Co-Administration With Other Protease Inhibitors |
| Atazanavir |
300 mg q.d.* |
400/100 mg b.i.d. † |
13 |
↔ |
1.02
(0.96-1.09) |
1.03
(0.94-1.12) |
1.01
(0.88-1.16) |
| Indinavir |
800 mg b.i.d. |
400/100 mg b.i.d. |
9 |
↑ |
1.11
(0.98-1.26) |
1.24
(1.09-1.42) |
1.44
(1.13-1.82) |
| Lopinavir/ Ritonavir |
400/100 mg b.i.d. |
1200/100 mg b.i.d.‡ |
14 |
↓ |
0.79
(0.67-0.92) |
0.62
(0.53-0.73) |
0.49
(0.39-0.63) |
| 533/133.3 mg b.i.d. |
1200 mg b.i.d.‡ |
15 |
↓ |
0.79
(0.64-0.97) |
0.59
(0.50-0.70) |
0.45
(0.38-0.52) |
| Saquinavir hard gel capsule |
1000 mg b.i.d. |
400/100 mg b.i.d. |
14 |
↓ |
0.83
(0.75-0.92) |
0.74
(0.63-0.86) |
0.58
(0.47-0.72) |
| Co-Administration With Other Antiretrovirals |
| Didanosine |
400 mg q.d. |
600/100 mg b.i.d. |
17 |
↔ |
0.93
(0.86-1.00) |
1.01
(0.95-1.07) |
1.07
(0.95-1.21) |
| Efavirenz |
600 mg q.d. |
300/100 mg b.i.d. |
12 |
↓ |
0.85
(0.72-1.00) |
0.87
(0.75-1.01) |
0.69
(0.54-0.87) |
| Etravirine |
200 mg b.i.d. |
600/100 mg b.i.d. |
15 |
↔ |
1.11
(1.01-1.22) |
1.15
(1.05-1.26) |
1.02
(0.90-1.17) |
| Nevirapine |
200 mg b.i.d. |
400/100 mg b.i.d. |
8 |
↑ |
1.40 §
(1.14-1.73) |
1.24 §
(0.97-1.57) |
1.02 §
(0.79-1.32) |
| Tenofovir Disoproxil Fumarate |
300 mg q.d. |
300/100 mg b.i.d. |
12 |
↑ |
1.16
(0.94-1.42) |
1.21
(0.95-1.54) |
1.24
(0.90-1.69) |
| Co-Administration With Other Drugs |
| Carbamazepine |
200 mg b.i.d. |
600/100 mg b.i.d. |
16 |
↔ |
1.04
(0.93-1.16) |
0.99
(0.90-1.08) |
0.85
(0.73-1.00) |
| Clarithromycin |
500 mg b.i.d. |
400/100 mg b.i.d. |
17 |
↔ |
0.83
(0.72-0.96) |
0.87
(0.75-1.01) |
1.01
(0.81-1.26) |
| Ketoconazole |
200 mg b.i.d. |
400/100 mg b.i.d. |
14 |
↑ |
1.21
(1.04-1.40) |
1.42
(1.23-1.65) |
1.73
(1.39-2.14) |
| Omeprazole |
20 mg q.d. |
400/100 mg b.i.d. |
16 |
↔ |
1.02
(0.95-1.09) |
1.04
(0.96-1.13) |
1.08
(0.93-1.25) |
| Paroxetine |
20 mg q.d. |
400/100 mg b.i.d. |
16 |
↔ |
0.97
(0.92-1.02) |
1.02
(0.95-1.10) |
1.07
(0.96-1.19) |
| Ranitidine |
150 mg b.i.d. |
400/100 mg b.i.d. |
16 |
↔ |
0.96
(0.89-1.05) |
0.95
(0.90-1.01) |
0.94
(0.90-0.99) |
| Rifabutin |
150 mg q.o.d. ¶ |
600/100 mg b.i.d. |
11 |
↑ |
1.42
(1.21-1.67) |
1.57
(1.28-1.93) |
1.75
(1.28-2.37) |
| Sertraline |
50 mg q.d. |
400/100 mg b.i.d. |
13 |
↔ |
1.01
(0.89-1.14) |
0.98
(0.84-1.14) |
0.94
(0.76-1.16) |
N = number of subjects with data; - = no information available.
* q.d. = once daily
† b.i.d. = twice daily
‡ The pharmacokinetic parameters of darunavir in this study were
compared with the pharmacokinetic parameters following administration
of darunavir/ritonavir 600/100 mg b.i.d.
§ Ratio based on between-study comparison.
¶ q.o.d. = every other day |
Table 11: Drug Interactions: Pharmacokinetic Parameters for
Co-administered Drugs in the Presence of Darunavir/Ritonavir
| Co-Administered Drug |
Dose/Schedule Co-Administered Drug |
Darunavir/ ritonavir |
N |
PK |
LS Mean Ratio (90% CI) of Co-Administered Drug Pharmacokinetic
Parameters With/Without Darunavir No effect =1.00 |
| Cmax |
AUC |
Cmin |
| Co-Administration With Other Protease Inhibitors |
| Atazanavir |
300 mg q.d.* /100 mg ritonavir q.d. when administered alone
300 mg q.d. when administered with darunavir/ ritonavir |
400/100 mg b.i.d. † |
13 |
↔ |
0.89
(0.781.01) |
1.08
(0.941.24) |
1.52
(0.992.34) |
| Indinavir |
800 mg b.i.d. /100 mg ritonavir b.i.d. when administered alone
800 mg b.i.d. when administered with darunavir/ ritonavir |
400/100 mg b.i.d. |
9 |
↑ |
1.08
(0.951.22) |
1.23
(1.061.42) |
2.25
(1.633.10) |
| Lopinavir/ Ritonavir |
400/100 mg b.i.d.‡ |
1200/100 mg b.i.d. |
14 |
↔ |
0.98
(0.781.22) |
1.09
(0.861.37) |
1.23
(0.901.69) |
| 533/133.3 mg b.i.d.‡ |
1200 mg b.i.d. |
15 |
↔ |
1.11
(0.961.30) |
1.09
(0.961.24) |
1.13
(0.901.42) |
| Saquinavir hard gel capsule |
1000 mg b.i.d. /100 mg ritonavir b.i.d. when administered alone
1000 mg b.i.d. when administered with darunavir/ ritonavir |
400/100 mg b.i.d. |
12 |
↔ |
0.94
(0.781.13) |
0.94
(0.761.17) |
0.82
(0.521.30) |
| Co-Administration With Other Antiretrovirals |
| Didanosine |
400 mg q.d. |
600/100 mg b.i.d. |
17 |
↔ |
0.84
(0.591.20) |
0.91
(0.751.10) |
- |
| Efavirenz |
600 mg q.d. |
300/100 mg b.i.d. |
12 |
↑ |
1.15
(0.971.35) |
1.21
(1.081.36) |
1.17
(1.011.36) |
| Etravirine |
100 mg b.i.d. |
600/100 mg b.i.d. |
14 |
↓ |
0.68
(0.570.82) |
0.63
(0.540.73) |
0.51
(0.440.61) |
| Nevirapine |
200 mg b.i.d. |
400/100 mg b.i.d. |
8 |
↑ |
1.18
(1.021.37) |
1.27
(1.121.44) |
1.47
(1.201.82) |
| Tenofovir Disoproxil Fumarate |
300 mg q.d. |
300/100 mg b.i.d. |
12 |
↑ |
1.24
(1.081.42) |
1.22
(1.101.35) |
1.37
(1.191.57) |
| Co-Administration With Other Drugs |
| Atorvastatin |
40 mg q.d. when administered alone
10 mg q.d. when administered with darunavir/ ritonavir |
300/100 mg b.i.d. |
15 |
↑ |
0.56
(0.480.67) |
0.85
(0.760.97) |
1.81
(1.372.40) |
| Carbamazepine |
200 mg b.i.d. |
600/100 mg b.i.d. |
16 |
↑ |
1.43
(1.341.53) |
1.45
(1.351.57) |
1.54
(1.411.68) |
| Carbamazepine epoxide |
|
|
16 |
↓ |
0.46
(0.430.49) |
0.46
(0.440.49) |
0.48
(0.450.51) |
| Clarithromycin |
500 mg b.i.d. |
400/100 mg b.i.d. |
17 |
↑ |
1.26
(1.031.54) |
1.57
(1.351.84) |
2.74
(2.303.26) |
| Dextromethorphan |
30 mg |
600/100 mg b.i.d. |
12 |
↑ |
1.27
(1.583.25) |
1.70
(1.804.05) |
- |
| Dextrorphan |
|
|
|
↓ |
0.86
(0.760.97) |
0.96
(0.891.03) |
- |
| Digoxin |
0.4 mg |
600/100 mg b.i.d. |
8 |
↑ |
1.15
(0.891.48) |
1.36
(0.812.27) |
- |
| Ethinyl Estradiol (EE) |
Ortho-Novum 1/35 (35 ?g EE / 1 mg NE) |
600/100 mg b.i.d. |
11 |
↓ |
0.68
(0.610.74) |
0.56
(0.500.63) |
0.38
(0.270.54) |
| Norethindrone (NE) |
|
|
11 |
↓ |
0.90
(0.830.97) |
0.86
(0.750.98) |
0.70
(0.510.97) |
| Ketoconazole |
200 mg b.i.d. |
400/100 mg b.i.d. |
15 |
↑ |
2.11
(1.812.44) |
3.12
(2.653.68) |
9.68
(6.4414.55) |
| R-Methadone |
55-150 mg q.d. |
600/100 mg b.i.d. |
16 |
↓ |
0.76
(0.710.81) |
0.84
(0.780.91) |
0.85
(0.770.94) |
| Omeprazole |
40 mg single dose |
600/100 mg b.i.d. |
12 |
↓ |
0.66
(0.480.90) |
0.58
(0.500.66) |
- |
| 5-hydroxy omeprazole |
|
|
|
↓ |
0.93
(0.711.21) |
0.84
(0.770.92) |
- |
| Paroxetine |
20 mg q.d. |
400/100 mg b.i.d. |
16 |
↓ |
0.64
(0.590.71) |
0.61
(0.560.66) |
0.63
(0.550.73) |
| Pravastatin |
40 mg single dose |
600/100 mg b.i.d. |
14 |
↑ |
1.63
(0.952.82) |
1.81
(1.232.66) |
- |
| Rifabutin |
150 mg q.o.d.§ when administered with PREZISTA/rtv |
600/100 mg b.i.d.¶ |
11 |
↑ |
0.72
(0.55 0.93) |
0.93
(0.80 1.09) |
1.64 |
| 25-O -desacetyl rifabutin |
300 mg q.d.when administered alone |
|
11 |
↑ |
4.77
(4.04 5.63) |
9.81
(8.09 11.9) |
27.1 |
| Sertraline |
50 mg q.d. |
400/100 mg b.i.d. |
13 |
↓ |
0.56
(0.49 0.63) |
0.51
(0.46-.058) |
0.51
(0.45-0.57) |
| Sildenafil |
100 mg (single dose)administered alone |
400/100 mg b.i.d. |
16 |
↑ |
0.62
(0.55 0.70) |
0.97
(0.86 1.09) |
- |
| 25 mg (single dose) when administered with darunavir/ritonavir |
| S-warfarin |
10 mg single dose |
600/100 mg b.i.d. |
12 |
↓ |
0.92
(0.86 0.97) |
0.79
(0.73 0.85) |
- |
| 7-OH-S-warfarin |
|
|
12 |
↑ |
1.42
(1.24 1.63) |
1.23
(0.97 1.57) |
- |
N =number of subjects with data;-=no information
available
.* q.d.=once daily
† b.i.d.=twice daily
‡The pharmacokinetic parameters of lopinavir in this study were
compared with the pharmacokinetic parameters following administration
of lopinavir/ritonavir 400/100 mg b.i.d.§ q.o.d.=every other day
¶ In comparison to rifabutin 300 mg q.d.
A cocktail study was conducted in 12 healthy volunteers to evaluate the
effect of steady state pharmacokinetics of darunavir/ritonavir on the
activity of CYP2D6 (using dextromethorphan as probe substrate),CYP2C9
(using warfarin as probe substrate),and CYP2C19 (using omeprazole as probe
substrate).The pharmacokinetic results are shown in Table 11. |
Microbiology
Mechanism of Action
Darunavir is an inhibitor of the HIV-1 protease. It
selectively inhibits the cleavage of HIV encoded Gag-Pol polyproteins in
infected cells, thereby preventing the formation of mature virus particles.
Antiviral Activity
Darunavir exhibits activity against laboratory strains and
clinical isolates of HIV-1 and laboratory strains of HIV-2 in acutely infected
T-cell lines, human peripheral blood mononuclear cells and human
monocytes/macrophages with median EC50 values ranging from 1.2 to 8.5 nM (0.7
to 5.0 ng/mL). Darunavir demonstrates antiviral activity in cell culture
against a broad panel of HIV-1 group M (A, B, C, D, E, F, G), and group O
primary isolates with EC50 values ranging from < 0.1 to 4.3 nM.
The EC50 value of darunavir increases by a median factor of 5.4 in
the presence of human serum. Darunavir did not show antagonism when studied in
combination with the PIs amprenavir, atazanavir, indinavir, lopinavir,
nelfinavir, ritonavir, saquinavir, or tipranavir, the N(t)RTIs abacavir,
didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zalcitabine, or
zidovudine, the NNRTIs delavirdine, efavirenz, etravirine, or nevirapine, and
the fusion inhibitor enfuvirtide.
Resistance
Cell Culture: HIV-1 isolates with a decreased
susceptibility to darunavir have been selected in cell culture and obtained
from subjects treated with darunavir/ritonavir. Darunavir-resistant virus
derived in cell culture from wild-type HIV had 21- to 88-fold decreased
susceptibility to darunavir and developed 2 to 4 of the following amino acid
substitutions S37D, R41E/T, K55Q, H69Q, K70E, T74S, V77I, or I85V in the
protease. Selection in cell culture of darunavir resistant HIV-1 from nine
HIV-1 strains harboring multiple PI resistance-associated mutations resulted in
the overall emergence of 22 mutations in the protease gene, coding for amino
acid substitutions L10F, V11I, I13V, I15V, G16E, L23I, V32I, L33F, S37N, M46I,
I47V, I50V, F53L, L63P, A71V, G73S, L76V, V82I, I84V, T91A/S, and Q92R, of
which L10F, V32I, L33F, S37N, M46I, I47V, I50V, L63P, A71V, and I84V were the
most prevalent. These darunavir-resistant viruses had at least eight protease
substitutions and exhibited 50- to 641-fold decreases in darunavir
susceptibility with final EC50 values ranging from 125 nM to 3461 nM.
Clinical studies of darunavir/ritonavir in
treatment-experienced subjects: In a pooled analysis of the 600/100 mg
PREZISTA/rtv twice daily arms of Studies TMC114-C213, TMC114-C202, TMC114-C215,
and the control arms of etravirine studies TMC125-C206 and TMC125-C216, the
amino acid substitutions V32I and I54L or M developed most frequently on
PREZISTA/rtv in 41% and 25%, respectively, of the treatment-experienced
subjects who experienced virologic failure, either by rebound or by never being
suppressed ( < 50 copies/mL). Other substitutions that developed frequently
in PREZISTA/rtv virologic failure isolates occurred at amino acid positions
V11I, I15V, L33F, I47V, I50V, and L89V. These amino acid substitutions were
associated with decreased susceptibility to darunavir; 90% of the virologic
failure isolates had a > 7-fold decrease in susceptibility to darunavir at
failure. The median darunavir phenotype (fold change from reference) of the
virologic failure isolates was 4.3-fold at baseline and 85-fold at failure.
Amino acid substitutions were also observed in the protease cleavage sites in
the Gag polyprotein of some PREZISTA/rtv virologic failure isolates. In Study
TMC114-C212 of treatment-experienced pediatric subjects, the amino acid
substitutions V32I, I54L and L89M developed most frequently in virologic
failures on PREZISTA/rtv.
In the 48-week analysis of the Phase 3 Study TMC114-C214,
the number of virologic failures was 17% (52/298) in the group of subjects
receiving PREZISTA/rtv 600/100 mg twice daily compared to 28% (84/297) of
subjects receiving lopinavir/ritonavir 400/100 mg twice daily. Examination of
subjects who failed on PREZISTA/rtv 600/100 mg twice daily and had
post-baseline genotypes and phenotypes showed that 6 subjects (6/33; 18%)
developed PI substitutions on darunavir/ritonavir treatment resulting in
decreased susceptibility to darunavir. The most common emerging PI
substitutions in these virologic failures were V32I, I47V, I54L, T74P and L76V.
These amino acid substitutions were associated with 44- to 607-fold decreased
susceptibility to darunavir at failure. Five of the 6 had baseline PI
resistance-associated substitutions and baseline darunavir phenotypes > 7.
In the comparator arm, 28 (28/69; 41%) lopinavir/ritonavir virologic failures
had reduced susceptibility to lopinavir ( > 10-fold change) at failure. Of
those 28 lopinavir/ritonavir failures, 13 had reduced susceptibility to
lopinavir at baseline. The other 15 lopinavir/ritonavir virologic failures
developed substitutions on lopinavir treatment resulting in decreased lopinavir
susceptibility. The most common substitutions developing were L10I/F, I47V/A,
L76V, M46I/L and I54V.
Clinical studies of darunavir/ritonavir in
treatment-naive subjects: In the 48-week analysis of the Phase 3 Study
TMC114-C211, the number of virologic failures was 10% in the group of subjects
receiving PREZISTA/rtv 800/100 mg once daily compared to 14% of subjects
receiving lopinavir/ritonavir 800/200 mg per day. No emergent PI-resistance
associated substitutions were identified in the virologic failures with
post-baseline genotypic data (n=12) in the PREZISTA/rtv arm and none of the
darunavir virologic failures had a decrease in darunavir susceptibility at
failure. None of the lopinavir/ritonavir virologic failures had resistance to
lopinavir at failure. The M184V substitution and resistance to emtricitabine,
which was included in the fixed background regimen, was identified in 1
virologic failure of the PREZISTA/rtv arm and 2 virologic failures in the
lopinavir/ritonavir arm.
Cross-resistance
Cross-resistance among PIs has been observed. Darunavir has
a < 10-fold decreased susceptibility in cell culture against 90% of 3309
clinical isolates resistant to amprenavir, atazanavir, indinavir, lopinavir,
nelfinavir, ritonavir, saquinavir and/or tipranavir showing that viruses
resistant to these PIs remain susceptible to darunavir.
Darunavir-resistant viruses were not susceptible to
amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir or
saquinavir in cell culture. However, six of nine darunavir-resistant viruses
selected in cell culture from PI resistant viruses showed a fold change in EC50
values < 3 for tipranavir, indicative of limited cross-resistance between
darunavir and tipranavir. In Studies TMC114-C213, TMC114-C202, and TMC114-C215,
34% (64/187) of subjects in the darunavir/ritonavir arm whose baseline isolates
had decreased susceptibility to tipranavir (tipranavir fold change > 3)
achieved < 50 copies/mL serum HIV RNA levels at Week 96. Of the viruses isolated
from subjects experiencing virologic failure on PREZISTA/rtv 600/100 mg twice
daily ( > 7 fold change), 41% were still susceptible to tipranavir and 10%
were susceptible to saquinavir while less than 2% were susceptible to the other
protease inhibitors (amprenavir, atazanavir, indinavir, lopinavir or
nelfinavir).
In Study TMC114-C214, 18% (6/33) of the darunavir/ritonavir
virologic failures were resistant to the approved PIs amprenavir, atazanavir,
lopinavir, and nelfinavir and 15% (5/33) were resistant to indinavir,
saquinavir and tipranavir. Most of the virologic failures (83%; 5/6) were
resistant to the PIs at baseline.
Cross-resistance between darunavir and nucleoside/nucleotide
reverse transcriptase inhibitors, non-nucleoside reverse transcriptase
inhibitors, fusion inhibitors, CCR5 co-receptor antagonists, or integrase
inhibitors is unlikely because the viral targets are different.
Baseline Genotype/Phenotype and Virologic Outcome Analyses
Genotypic and/or phenotypic analysis of baseline virus may
aid in determining darunavir susceptibility before initiation of PREZISTA/rtv
600/100 mg twice daily therapy. The effect of baseline genotype and phenotype
on virologic response at 96 weeks was analyzed in as-treated analyses using
pooled data from the Phase 2b studies (Studies TMC114-C213, TMC114-C202, and
TMC114-C215) (n=439). The findings were confirmed with additional genotypic and
phenotypic data from the control arms of etravirine Studies TMC125-C206 and
TMC125C216 at Week 24 (n=591).
Diminished virologic responses were observed in subjects
with 5 or more baseline IAS-defined primary protease inhibitor
resistance-associated substitutions (D30N, V32I, L33F, M46I/L, I47A/V, G48V,
I50L/V, I54L/M, L76V, V82A/F/L/S/T, I84V, N88S, L90M) (see Table 12).
Table 12: Response to PREZISTA/rtv 600/100 mg twice daily
by Baseline Number of IAS-Defined Primary PI Resistance-Associated Substitutions:
As-treated Analysis of Studies TMC114-C213, TMC114-C202, and TMC114-C215
| |
Studies TMC114-C213, TMC114-C202, TMC114-C215 < 50 copies/mL
at Week 96 N=439 |
| # IAS-Defined Primary PI Substitutions |
Overall |
De Novo ENF |
Re-Used/No ENF |
| All |
44% (192/439) |
54% (61/112) |
40% (131/327) |
| 0 - 4 |
50% (162/322) |
58% (49/85) |
48% (113/237) |
| 5 |
22% (16/74) |
47% (9/19) |
13% (7/55) |
| ≥ 6 |
9% (3/32) |
17% (1/6) |
8% (2/26) |
IAS Primary PI Substitutions (2008): D30N, V32I, L33F,
M46I/L, I47A/V, G48V, I50L/V, I54L/M, L76V, V82A/F/L/S/T, I84V, N88S, L90M
The presence at baseline of two or more of the substitutions
V11I, V32I, L33F, I47V, I50V, I54L or M, T74P, L76V, I84V or L89V was
associated with a decreased virologic response to PREZISTA/rtv. In subjects not
taking enfuvirtide de novo, the proportion of subjects achieving viral load
< 50 plasma HIV RNA copies/mL at 96 weeks was 59%, 29%, and 12% when the
baseline genotype had 0-1, 2 and ≥ 3 of these substitutions,
respectively.
Baseline darunavir phenotype (shift in susceptibility
relative to reference) was shown to be a predictive factor of virologic
outcome. Response rates assessed by baseline darunavir phenotype are shown in
Table 13. These baseline phenotype groups are based on the select patient
populations in the Studies TMC114-C213, TMC114-C202, and TMC114-C215, and are
not meant to represent definitive clinical susceptibility breakpoints for
PREZISTA/rtv. The data are provided to give clinicians information on the
likelihood of virologic success based on pre-treatment susceptibility to
darunavir.
Table 13: Response (HIV-1 RNA < 50 copies/mL at Week 96)
to PREZISTA/rtv 600/100 mg twice daily by Baseline Darunavir Phenotype and by
Use of Enfuvirtide (ENF): As-treated Analysis of Studies TMC114C213, TMC114-C202,
and TMC114-C215
| |
Proportion of Subjects with < 50 copies/mL at Week 96
N=417 |
| Baseline DRV Phenotype |
All |
De Novo ENF |
Re-Used/No ENF |
| Overall |
175/417 (42%) |
61/112 (54%) |
131/327 (40%) |
| 0 - 7 |
148/270 (55%) |
44/65 (68%) |
104/205 (51%) |
| > 7 - 20 |
16/53 (30%) |
7/17 (41%) |
9/36 (25%) |
| > 20 |
11/94 (12%) |
6/23 (26%) |
5/71 (7%) |
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, and Impairment of Fertility
Carcinogenesis and Mutagenesis
Darunavir was evaluated for carcinogenic potential by oral
gavage administration to mice and rats up to 104 weeks. Daily doses of 150, 450
and 1000 mg/kg were administered to mice and doses of 50, 150 and 500 mg/kg
were administered to rats. A dose-related increase in the incidence of
hepatocellular adenomas and carcinomas were observed in males and females of
both species as well as an increase in thyroid follicular cell adenomas in male
rats. The observed hepatocellular findings in rodents are considered to be of
limited relevance to humans. Repeated administration of darunavir to rats
caused hepatic microsomal enzyme induction and increased thyroid hormone
elimination, which predispose rats, but not humans, to thyroid neoplasms. At
the highest tested doses, the systemic exposures to darunavir (based on AUC)
were between 0.4- and 0.7-fold (mice) and 0.7-and 1-fold (rats), relative to
those observed in humans at the recommended therapeutic doses (600/100 mg twice
daily or 800/100 mg once daily).
Darunavir was not mutagenic or genotoxic in a battery of in
vitro and in vivo assays including bacterial reserve mutation (Ames), chromosomal aberration in human lymphocytes and in vivo micronucleus test in mice.
Impairment of Fertility
No effects on fertility or early embryonic development were
observed with darunavir in rats and darunavir has shown no teratogenic
potential in mice (in the presence or absence of ritonavir), rats and rabbits.
Animal Toxicology and/or Pharmacology
In juvenile rats single doses of darunavir (20 mg/kg to 160
mg/kg at ages 5-11 days) or multiple doses of darunavir (40 mg/kg to 1000 mg/kg
at age 12 days) caused mortality. The mortalities were associated with
convulsions in some of the animals. Within this age range exposures in plasma,
liver and brain were dose and age dependent and were considerably greater than
those observed in adult rats. These findings were attributed to the ontogeny of
the CYP450 liver enzymes involved in the metabolism of darunavir and the immaturity
of the blood-brain barrier. No treatment-related mortalities were noted in
juvenile rats after a single dose of darunavir at 1000 mg/kg on day 26 of age
or after repeat dosing at 500 mg/kg from day 23 to 50 of age. The exposures and
toxicity profile in the older animals (day 23 or day 26) were comparable to
those observed in adult rats. Due to uncertainties regarding the rate of
development of the human blood-brain barrier and liver enzymes, do not
administer PREZISTA/rtv in pediatric patients below 3 years of age.
Clinical Studies
Description of Adult Clinical Studies
The evidence of efficacy of PREZISTA/rtv is based on the analyses of 48-week
data from 2 randomized, controlled open-label Phase 3 trials in treatment-naïve
(TMC114-C211) and antiretroviral treatment-experienced (TMC114 C214) HIV-1-infected
adult subjects. In addition, 96-week data is included from 2 randomized, controlled
Phase 2b trials, TMC114-C213 and TMC114-C202, in antiretroviral treatment-experienced
HIV-1-infected adult subjects.
Treatment-Naïve Adult Subjects
Study TMC114-C211
Study TMC114-C211 is an ongoing randomized, controlled,
open-label Phase 3 trial comparing PREZISTA/rtv 800/100 mg once daily versus
lopinavir/ritonavir 800/200 mg per day (given as a twice daily or as a once
daily regimen) in antiretroviral treatment-naïve HIV-1-infected adult
subjects. Both arms used a fixed background regimen consisting of tenofovir
disoproxil fumarate 300 mg once daily (TDF) and emtricitabine 200 mg once daily
(FTC).
HIV-1-infected subjects who were eligible for this trial had
plasma HIV-1 RNA ≥ 5000 copies/mL. Randomization was stratified by
screening plasma viral load (HIV-1 RNA < 100,000 copies/mL or ≥ 100,000 copies/mL) and screening CD4+ cell count ( < 200 cells/mm³ or ≥ 200 cells/mm³). Virologic response was defined as a confirmed plasma HIV-1 RNA
viral load < 50 copies/mL. Analyses included 689 subjects in Study
TMC114-C211 who had completed 48 weeks of treatment or discontinued earlier.
Demographics and baseline characteristics were balanced
between the PREZISTA/rtv arm and the lopinavir/ritonavir arm (see Table 14).
Table 14 compares the demographic and baseline characteristics between subjects
in the PREZISTA/rtv 800/100 mg once daily arm and subjects in the
lopinavir/ritonavir 800/200 mg per day arm in Study TMC114-C211.
Table 14: Demographic and Baseline Characteristics of Subjects
in Study TMC114-C211
| |
Randomized Study TMC114-C211 |
PREZISTA/rtv
800/100 mg once daily + TDF/FTC
N = 343 |
lopinavir/ritonavir
800/200 mg per day + TDF/FTC
N = 346 |
| Demographic Characteristics |
| Median Age (years) |
34 |
33 |
| (range, years) |
(18-70) |
(19-68) |
| Sex |
| Male |
70% |
70% |
| Female |
30% |
30% |
| Race |
| White |
40% |
45% |
| Black |
23% |
21% |
| Hispanic |
23% |
22% |
| Asian |
13% |
11% |
| Baseline Characteristics |
| Mean Baseline Plasma HIV-1 RNA (log10 copies/mL) |
4.86 |
4.84 |
| Median Baseline CD4+ Cell Count (cells/mm³) (range,
cells/mm³) |
228 |
218 |
| (4-750) |
(2-714) |
| Percentage of Patients with Baseline Viral Load ≥ 100,000 copies/mL |
34% |
35% |
| Percentage of Patients with Baseline CD4+Cell Count < 200 cells/mm³ |
41% |
43% |
Week 48 outcomes for subjects on PREZISTA/rtv 800/100 mg
once daily from Study TMC114-C211 are shown in Table 15.
Table 15: Outcomes of Randomized Treatment Through Week 48
of Study TMC114-C211
| |
Randomized Study TMC114-C211 |
PREZISTA/rtv
800/100 mg once daily + TDF/FTC
N = 343 |
lopinavir/ritonavir
800/200 mg per day + TDF/FTC
N = 346 |
| Virologic Responders HIV-1 RNA < 50 copies/mL |
84% |
78% |
| Virologic failures |
6% |
10% |
| Rebounder* |
2% |
3% |
| Never suppressed† |
4% |
8% |
| Death or discontinuation due to |
4% |
6% |
| adverse events |
|
|
| Discontinuation due to other reasons |
7% |
6% |
N = total number of subjects with data
*Subjects with a confirmed viral load < 50 copies/mL before Week 48,
but without a confirmed viral load < 50 copies/mL at Week 48
† Subjects who never reached a confirmed viral load < 50 copies/mL
before Week 48 |
In Study TMC114-C211 through 48 weeks of treatment, the
proportion of subjects with HIV-1 RNA < 400 copies/mL in the arm receiving
PREZISTA/rtv 800/100 mg once daily compared to the arm receiving
lopinavir/ritonavir 800/200 mg per day was 87.8% and 85.3%, respectively. The
median increase from baseline in CD4+ cell counts was comparable for both
treatment groups (137 cells/mm³ and 141 cells/mm³ in the PREZISTA/rtv 800/100
mg once daily arm and the lopinavir/ritonavir 800/200 mg per day arm, respectively).
The virological response ( < 50 copies/mL) by baseline
viral load is presented in Table 16.
Table 16: Virological Response ( < 50 copies/mL) by BaselineViral
Load
| |
PREZISTA/rtv 800/100 mg once daily n=343 |
lopinavir/ritonavir 800/200 mg per day n=346 |
Treatment Difference |
| N |
number of responders n (%) |
N |
number of responders n (%) |
Difference in % response (95% CI of difference
in % response) |
| Baseline plasma viral load (copies/mL) |
| < 100,000 |
226 |
194 (86) |
226 |
191 (85) |
1.3 (-5; 8) |
| ≥ 100,000 |
117 |
93 (80) |
120 |
80 (67) |
12.8 (2; 24) |
Treatment-Experienced Adult Subjects
Study TMC114-C214
Study TMC114-C214 is an ongoing randomized, controlled,
open-label Phase 3 trial comparing PREZISTA/rtv 600/100 mg twice daily versus
lopinavir/ritonavir 400/100 mg twice daily in antiretroviral
treatment-experienced, lopinavir/ritonavir-naïve HIV-1-infected adult
subjects. Both arms used an optimized background regimen (OBR) consisting of at
least 2 antiretrovirals (NRTIs with or without NNRTIs).
HIV-1-infected subjects who were eligible for this trial had
plasma HIV-1 RNA > 1000 copies/mL and were on a highly active antiretroviral
therapy regimen (HAART) for at least 12 weeks. Virologic response was defined
as a confirmed plasma HIV-1 RNA viral load < 400 copies/mL. Analyses
included 595 subjects in Study TMC114-C214 who had completed 48 weeks of
treatment or discontinued earlier.
Demographics and baseline characteristics were balanced
between the PREZISTA/rtv arm and the lopinavir/ritonavir arm (see Table 17).
Table 17 compares the demographic and baseline characteristics between subjects
in the PREZISTA/rtv 600/100 mg twice daily arm and subjects in the
lopinavir/ritonavir 400/100 mg twice daily arm in Study TMC114-C214.
Table 17: Demographic and Baseline Characteristics of Subjects
in Study TMC114-C214
| |
Randomized Study TMC114-C214 |
PREZISTA/rtv
600/100 mg twice daily + OBR
N = 298 |
lopinavir/ritonavir
400/100 mg twice
daily + OBR
N = 297 |
| Demographic Characteristics |
| Median Age (years) (range, years) |
40 (18-68) |
41 (22-76) |
| Sex |
| Male |
77% |
81% |
| Female |
23% |
19% |
| Race |
| White |
54% |
57% |
| Black |
18% |
17% |
| Hispanic |
15% |
15% |
| Asian |
9% |
9% |
| Baseline Characteristics |
| Mean Baseline Plasma HIV-1 RNA (log10 copies/mL) |
4.33 |
4.28 |
| Median Baseline CD4+ Cell Count (cells/mm³)(range, cells/mm³) |
235(3-831) |
230(2-1096) |
| Percentage of Patients with Baseline Viral Load ≥ 100,000 copies/mL |
19% |
17% |
| Percentage of Patients with Baseline CD4+Cell Count < 200 cells/mm³ |
40% |
40% |
| Median Darunavir Fold Change(range) |
0.60 (0.10-37.40) |
0.60 (0.1-43.8) |
| Median Lopinavir Fold Change(range) |
0.70 (0.40-74.40) |
0.80 (0.30-74.50) |
| Median Number of Resistance-Associated*: |
| PI mutations |
4 |
4 |
| NNRTI mutations |
1 |
1 |
| NRTI mutations |
2 |
2 |
| Percentage of Subjects with Number of Baseline Primary
Protease Inhibitor Mutations*: |
| ≤ 1 |
78% |
80% |
| 2 |
8% |
9% |
| ≥ 3 |
13% |
11% |
| Median Number of ARVs Previously Used†: |
| NRTIs |
4 |
4 |
| NNRTIs |
1 |
1 |
| PIs (excluding low-dose ritonavir) |
1 |
1 |
| Percentage of Subjects Resistant‡ to All Available§
PIs at Baseline, excluding Darunavir |
2% |
3% |
* Johnson VA, Brun-Vezinet F, Clotet B, et al. Update of
the drug resistance mutations in HIV-1: Fall 2006. Top HIV Med 2006; 14(3):
125-130
†Only counting ARVs, excluding low-dose ritonavir
‡ Based on phenotype (Antivirogram™)
§Commercially available PIs at the time of study enrollment |
Week 48 outcomes for subjects on PREZISTA/rtv 600/100 mg
twice daily from Study TMC114-C214 are shown in Table 18.
Table 18: Outcomes of Randomized Treatment Through Week 48
of Study TMC114-C214
| |
Randomized Study TMC114-C214 |
PREZISTA/rtv
600/100 mg twice
daily + OBR
N = 298 |
lopinavir/ritonavir
400/100 mg twice
daily+ OBR
N = 297 |
| Virologic Responders |
| HIV-1 RNA < 400 copies/mL |
77% |
67% |
| (HIV-1 RNA < 50 copies/mL) |
(71%) |
(60%) |
| Virologic failures |
11% |
21% |
| Lack of initial response* |
7% |
14% |
| Rebounder† |
3% |
7% |
| Discontinued due to virologic failure: never suppressed‡ |
0% |
< 1% |
| Death or discontinuation due to adverse events |
6% |
5% |
| Discontinuation due to other reasons |
7% |
9% |
N = total number of subjects with data
* Subjects with viral load ≥ 400 copies/mL at Week 16
†Subjects with a confirmed viral load < 400 copies/mL before
Week 48, but without a confirmed viral load < 400 copies/mL at Week
48
‡Subjects who never reached a confirmed viral load < 400copies/mL
before Week 48 |
In Study TMC114-C214 through 48 weeks of treatment, the
median increase from baseline in CD4+ cell counts was comparable for both
treatment groups (88 cells/mm³ and 81 cells/mm³ in the PREZISTA/rtv 600/100 mg
twice daily arm and lopinavir/ritonavir 400/100 mg twice daily arm,
respectively).
Studies TMC114-C213 and TMC114-C202
Studies TMC114-C213 and TMC114-C202 are randomized, controlled,
Phase 2b trials in adult subjects with a high level of PI resistance consisting
of 2 parts: an initial partially-blinded, dose-finding part and a second
long-term part in which all subjects randomized to PREZISTA/rtv received the
recommended dose of 600/100 mg twice daily.
HIV-1-infected subjects who were eligible for these trials
had plasma HIV-1 RNA > 1000 copies/mL, had prior treatment with PI(s),
NNRTI(s) and NRTI(s), had at least one primary PI mutation (D30N, M46I/L, G48V,
I50L/V, V82A/F/S/T, I84V, L90M) at screening, and were on a stable
PI-containing regimen at screening for at least 8 weeks. Randomization was
stratified by the number of PI mutations, screening viral load, and the use of
enfuvirtide.
The virologic response rate was evaluated in subjects
receiving PREZISTA/rtv plus an OBR versus a control group receiving an
investigator-selected PI(s) regimen plus an OBR. Prior to randomization, PI(s)
and OBR were selected by the investigator based on genotypic resistance testing
and prior ARV history. The OBR consisted of at least 2 NRTIs with or without
enfuvirtide. Selected PI(s) in the control arm included: lopinavir in 36%,
(fos)amprenavir in 34%, saquinavir in 35% and atazanavir in 17%; 98% of control
subjects received a ritonavir boosted PI regimen out of which 23% of control
subjects used dual-boosted PIs. Approximately 47% of all subjects used
enfuvirtide, and 35% of the use was in subjects who were ENF-naïve.
Virologic response was defined as a decrease in plasma HIV-1 RNA viral load of
at least 1 log10 versus baseline.
In the pooled analysis for TMC114-C213 and TMC114-C202,
demographics and baseline characteristics were balanced between the
PREZISTA/rtv arm and the comparator PI arm (see Table 19). Table 19 compares
the demographic and baseline characteristics between subjects in the
PREZISTA/rtv 600/100 mg twice daily arm and subjects in the comparator PI arm
in the pooled analysis of Studies TMC114-C213 and TMC114-C202.
Table 19: Demographic and Baseline Characteristics of Subjects
in the Studies TMC114-C213 and TMC114C202 (Pooled Analysis)
| |
Randomized Studies
TMC114-C213 and TMC114-C202 |
PREZISTA/rtv
600/100 mg twice
daily + OBR
N = 131 |
Comparator PI(s)
+ OBR
N = 124 |
| Demographic Characteristics |
| Median Age (years)(range, years) |
43(27-73) |
44(25-65) |
| Sex |
| Male |
89% |
88% |
| Female |
11% |
12% |
| Race |
| White |
81% |
73% |
| Black |
10% |
15% |
| Hispanic |
7% |
8% |
| Baseline Characteristics |
| Mean Baseline Plasma HIV-1 RNA (log10 copies/mL) |
4.61 |
4.49 |
| Median Baseline CD4+ Cell Count(cells/mm³) (range, cells/mm³) |
153(3-776) |
163(3-1274) |
| Percentage of Patients with Baseline Viral Load > 100,000 copies/mL |
24% |
29% |
| Percentage of Patients with Baseline CD4+ Cell Count < 200 cells/mm³ |
67% |
58% |
| Median Darunavir Fold Change |
4.3 |
3.3 |
| Median Number of Resistance-Associated*: |
| PI mutations |
12 |
12 |
| NNRTI mutations |
1 |
1 |
| NRTI mutations |
5 |
5 |
| Percentage of Subjects with Number of Baseline Primary
Protease Inhibitor Mutations*: |
| ≤ 1 |
8% |
9% |
| 2 |
22% |
21% |
| ≥ 3 |
70% |
70% |
| Median Number of ARVs Previously Used†: |
| NRTIs |
6 |
6 |
| NNRTIs |
1 |
1 |
| PIs (excluding low-dose ritonavir) |
5 |
5 |
| Percentage of Subjects Resistant † to All Available‡ PIs
at Baseline, excluding Tipranavir and Darunavir |
63% |
61% |
| Percentage of Subjects with Prior Use of Enfuvirtide |
20% |
17% |
* Johnson VA, Brun-Vezinet F, Clotet B, et al. Update of
the drug resistance mutations in HIV-1 :Fall 2006. Top HIV Med 2006; 14(3):
125-130
†Based on phenotype (Antivirogram™)
‡Commercially available PIs at the time of study enrollment |
Week 96 outcomes for subjects on the recommended dose
PREZISTA/rtv 600/100 mg twice daily from the pooled Studies TMC114-C213 and
TMC114-C202 are shown in Table 20.
Table 20: Outcomes of Randomized Treatment Through Week 96
of the Studies TMC114-C213 and TMC114-C202 (Pooled Analysis)
| |
Randomized Studies
TMC114-C213 and TMC114-C202 |
PREZISTA/rtv
600/100 mg twice
daily + OBR
N=131 |
Comparator
PI + OBR
N=124 |
| Virologic Responders confirmed at least 1 log10 HIV-1 RNA
below baseline through Week 96(< 50 copies/mL at Week 96) |
57%(39%) |
10%(9%) |
| Virologic failures |
29% |
80% |
| Lack of initial response* |
8% |
53% |
| Rebounder† |
17% |
19% |
| Never Suppressed‡ |
4% |
8% |
| Death or discontinuation due to adverse events |
9% |
3% |
| Discontinuation due to other reasons |
5% |
7% |
* Subjects who did not achieve at least a confirmed 0.5
log10 HIV-1 RNA drop from baseline at Week 12
†Subjects with an initial response (confirmed 1 log10
drop in viral load), but without aconfirmed 1 log 10 drop in vira lload
at Week 96
‡Subjects who never reached a confirmed 1 log10 drop
in viral load before Week 96 |
In the pooled Studies TMC114-C213 and TMC114-C202 through 48
weeks of treatment, the proportion of subjects with HIV-1 RNA < 400
copies/mL in the arm receiving PREZISTA/rtv 600/100 mg twice daily compared to
the comparator PI arm was 55.0% and 14.5%, respectively. In addition, the mean
changes in plasma HIV-1 RNA from baseline were -1.69 log10 copies/mL in
the arm receiving PREZISTA/rtv 600/100 mg twice daily and -0.37 log10
copies/mL for the comparator PI arm. The mean increase from baseline in CD4+
cell counts was higher in the arm receiving PREZISTA/rtv 600/100 mg twice daily
(103 cells/mm³) than in the comparator PI arm (17 cells/mm³).
Pediatric Patients
The pharmacokinetic profile, safety and antiviral activity
of PREZISTA/rtv were evaluated in a randomized, open-label, multicenter study.
This study enrolled treatment-experienced pediatric subjects between the ages
of 6 and < 18 years and weighing at least 44 lbs (20 kg). Patients were
stratified according to their weight ( ≥ 20 - < 30 kg, ≥ 30 -
< 40 kg, ≥ 40 kg) and received PREZISTA/rtv plus background therapy
consisting of at least two non-protease inhibitor antiretroviral drugs. Eighty
patients were randomized and received at least one dose of PREZISTA/rtv.
Pediatric subjects who were at risk of discontinuing therapy due to intolerance
of ritonavir oral solution (e.g., taste aversion) were allowed to switch to the
capsule formulation. Of the 44 pediatric subjects taking ritonavir oral
solution, 23 subjects switched to the 100 mg capsule formulation and exceeded
the weight-based ritonavir dose without changes in observed safety.
The 80 randomized pediatric subjects had a median age of 14
(range 6 - < 18 years), and were 71% male, 54% Caucasian, 30% Black, 9%
Hispanic and 8% other. The mean baseline plasma HIV-1 RNA was 4.64 log10
copies/mL, and the median baseline CD4+ cell count was 330 cells/mm³ (range: 6
to 1505 cells/mm³). Overall, 38% of pediatric subjects had baseline plasma
HIV-1 RNA ≥ 100,000 copies/mL. Most pediatric subjects (79%) had previous
use of at least one NNRTI and 96% of pediatric subjects had previously used at
least one PI.
Seventy-seven pediatric subjects (96%) completed the 24 week
period. Of the patients who discontinued, one patient discontinued treatment
due to an adverse event. An additional 2 patients discontinued for other
reasons, one patient due to compliance and another patient due to relocation.
The proportion of pediatric subjects with HIV-1 RNA < 400
copies/mL and < 50 copies/mL was 64% and 50%, respectively. The mean CD4+
cell count increase from baseline was 117 cells/mm³.
The dose selection was based on the following:
- Similar darunavir plasma exposures in children compared to adults
- Similar virologic response rates and safety profile in children compared
to adults
Last updated on RxList: 7/7/2009