CLINICAL PHARMACOLOGY
Mechanism Of Action
Doravirine is an antiretroviral
drug [see Microbiology].
Pharmacodynamics
In a Phase 2 trial evaluating
doravirine over a dose range of 0.25 to 2 times the recommended dose of
PIFELTRO, (in combination with FTC/TDF) in HIV-1 infected subjects with no
antiretroviral treatment history, no exposure-response relationship for
efficacy was identified for doravirine.
Cardiac Electrophysiology
At a doravirine dose of 1200
mg, which provides approximately 4 times the peak concentration observed
following the recommended dose of PIFELTRO, doravirine does not prolong the QT
interval to any clinically relevant extent.
Pharmacokinetics
Doravirine pharmacokinetics are
similar in healthy subjects and HIV-1-infected subjects. Doravirine
pharmacokinetics are provided in Table 7.
Table 7: Pharmacokinetic Properties of Doravirine
Parameter |
Doravirine |
General |
Steady State Exposure*† |
|
AUC0-24 (mcg•h/mL) |
16.1 (29) |
Cmax (mcg/mL) |
0.962 (19) |
C24 (mcg/mL) |
0.396 (63) |
Time to Steady State (Days) |
2 |
Accumulation Ratio |
1.2 to 1.4 |
Absorption |
Absolute Bioavailability |
64% |
Tmax (h) |
2 |
Effect of Food‡ |
|
AUC Ratio |
1.16 (1.06, 1.26) |
Cmax Ratio |
1.03 (0.89, 1.19) |
C24 Ratio |
1.36 (1.19, 1.55) |
Distribution |
Vdss (L)§ |
60.5 |
Plasma Protein Binding |
76% |
Elimination |
t½ (h) |
15 |
CL/F (mL/min)† |
106 (35.2) |
CLrenal (mL/min)† |
9.3 (18.6) |
Metabolism |
Primary Pathway(s) |
CYP3A |
Excretion |
Major Route of Elimination |
Metabolism |
Urine (unchanged) |
6% |
Biliary/Fecal (unchanged) |
Minor |
*Doravirine 100 mg once daily to HIV-1 infected subjects
†Presented as geometric mean (%CV: geometric coefficient of variation)
‡Geometric mean ratio [high-fat meal/fasting] and (90% confidence interval) for
PK parameters. High fat meal is approximately 1,000 kcal, 50% fat. The effect
of food is not clinically relevant.
§Based on IV dose
Abbreviations: AUC=area under the time concentration curve; Cmax=maximum
concentration; C24=concentration at 24 hours; Tmax time to Cmax; Vdss= volume
of distribution at steady state, t½=elimination half-life; CL/F=apparent
clearance; CLrenal=apparent renal clearance |
Specific Populations
No clinically significant
difference on the pharmacokinetics of doravirine were observed based on age (18
to 78 years of age), sex, and race/ethnicity, mild to severe renal impairment
(creatinine clearance (CLcr) >15 mL/min, estimated by Cockcroft-Gault), or
moderate hepatic impairment (Child-Pugh B). The pharmacokinetics of doravirine
in patients with end-stage renal disease or undergoing dialysis, severe hepatic
impairment (Child-Pugh C), or <18 years of age is unknown.
Patients With Renal Impairment
In a study comparing 8 subjects
with severe renal impairment to 8 subjects without renal impairment, the single
dose exposure of doravirine was 43% higher in subjects with severe renal
impairment. In a population pharmacokinetic analysis, renal function did not
have a clinically relevant effect on doravirine pharmacokinetics. Doravirine
has not been studied in patients with end-stage renal disease or in patients
undergoing dialysis [see Use In Specific Populations].
Patients With Hepatic Impairment
No clinically significant difference in the
pharmacokinetics of doravirine was observed in subjects with moderate hepatic
impairment (Child-Pugh score B) compared to subjects without hepatic
impairment. Doravirine has not been studied in subjects with severe hepatic
impairment (Child-Pugh score C) [see Use In Specific Populations].
Drug Interaction Studies
Doravirine is primarily metabolized by CYP3A, and drugs
that induce or inhibit CYP3A may affect the clearance of doravirine.
Co-administration of doravirine and drugs that induce CYP3A may result in
decreased plasma concentrations of doravirine. Co-administration of doravirine
and drugs that inhibit CYP3A may result in increased plasma concentrations of
doravirine.
Doravirine is not likely to have a clinically relevant
effect on the exposure of medicinal products metabolized by CYP enzymes.
Doravirine did not inhibit major drug metabolizing enzymes in vitro, including
CYPs 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4, and UGT1A1 and is not likely to be an
inducer of CYP1A2, 2B6, or 3A4. Based on in vitro assays, doravirine is not
likely to be an inhibitor of OATP1B1, OATP1B3, P-glycoprotein, BSEP, OAT1,
OAT3, OCT2, MATE1, and MATE2K. Drug interaction studies were performed with
doravirine and other drugs likely to be co-administered or commonly used as
probes for pharmacokinetic interactions. The effects of co-administration with
other drugs on the exposure (Cmax, AUC, and C24) of doravirine are summarized
in Table 8. A single doravirine 100 mg dose was administered in these studies
unless otherwise noted.
Table 8: Drug Interactions: Changes in Pharmacokinetic
Parameter Values of Doravirine in the Presence of Co-administered Drug
Co-administered Drug |
Regimen of Coadministered Drug |
N |
Geometric Mean Ratio (90% CI) of Doravirine Pharmacokinetics with/without Co-administered Drug (No Effect=1.00) |
AUC* |
Cmax |
C24 |
Azole Antifungal Agents |
ketoconazole† |
400 mg QD |
10 |
3.06 (2.85, 3.29) |
1.25 (1.05, 1.49) |
2.75 (2.54, 2.98) |
Antimycobacterials |
rifampin |
600 mg QD |
10 |
0.12 (0.10, 0.15) |
0.43 (0.35, 0.52) |
0.03 (0.02, 0.04) |
rifabutin |
300 mg QD |
12 |
0.50 (0.45, 0.55) |
0.99 (0.85, 1.15) |
0.32 (0.28, 0.35) |
HIV Antiviral Agents |
ritonavir†,‡ |
100 mg BID |
8 |
3.54 (3.04, 4.11) |
1.31 (1.17, 1.46) |
2.91 (2.33, 3.62) |
efavirenz |
600 mg QD§ |
17 |
0.38 (0.33, 0.45) |
0.65 (0.58, 0.73) |
0.15 (0.10, 0.23) |
600 mg QD¶ |
17 |
0.68 (0.58, 0.80) |
0.86 (0.77, 0.97) |
0.50 (0.39, 0.64) |
CI = confidence interval; QD = once daily; BID = twice
daily
*AUC0-∞ for single-dose, AUC0-24 for once daily.
†Changes in doravirine pharmacokinetic values are not clinically relevant.
‡A single doravirine 50 mg dose (0.5 times the recommended approved dose) was
administered.
§The first day following the cessation of efavirenz therapy and initiation of
doravirine 100 mg QD.
¶14 days following the cessation of efavirenz therapy and initiation of
doravirine 100 mg QD. |
Based on drug interaction
studies conducted with doravirine, no clinically significant drug interactions
have been observed following the co-administration of doravirine and the
following drugs: dolutegravir, ritonavir, TDF, lamivudine, elbasvir and
grazoprevir, ledipasvir and sofosbuvir, ketoconazole, aluminum
hydroxide/magnesium hydroxide/simethicone containing antacid, pantoprazole,
atorvastatin, an oral contraceptive containing ethinyl estradiol and
levonorgestrel, metformin, methadone, and midazolam.
Microbiology
Mechanism Of Action
Doravirine is a pyridinone non-nucleoside reverse
transcriptase inhibitor of HIV-1 and inhibits HIV-1 replication by
non-competitive inhibition of HIV-1 reverse transcriptase (RT). The inhibitory
concentration at 50% (IC50) of doravirine for RNA-dependent DNA polymerization
of recombinant wild-type HIV-1 RT in a biochemical assay was 12.2ñ2.0 nM (n=3).
Doravirine does not inhibit the human cellular DNA polymerases α, β,
and mitochondrial DNA polymerase γ.
Antiviral Activity In Cell Culture
Doravirine exhibited an EC50 value of 12.0ñ4.4 nM against
wild-type laboratory strains of HIV-1 when tested in the presence of 100%
normal human serum (NHS) using MT4-GFP reporter cells and a median EC50 value
for HIV-1 subtype B primary isolates (n=118) of 4.1 nM (range: 1.0 nM-16.0 nM).
Doravirine demonstrated antiviral activity against a broad panel of primary
HIV-1 isolates (A, A1, AE, AG, B, BF, C, D, G, H) with EC50 values ranging from
1.2 nM to 10.0 nM.
Antiviral Activity In Combination With Other HIV
Antiviral Agents
The antiviral activity of doravirine in cell culture was
not antagonistic when combined with the NNRTIs delavirdine, efavirenz,
etravirine, nevirapine, or rilpivirine; the NRTIs abacavir, didanosine,
emtricitabine, lamivudine, stavudine, tenofovir DF, or zidovudine; the PIs
darunavir or indinavir; the gp41 fusion inhibitor enfuvirtide; the CCR5
co-receptor antagonist maraviroc; or the integrase strand transfer inhibitor
raltegravir.
Resistance
In Cell Culture
Doravirine-resistant strains were selected in cell
culture starting from wild-type HIV-1 of different origins and subtypes, as
well as NNRTI-resistant HIV-1. Observed emergent amino acid substitutions in RT
included: V106A, V106I, V106M, V108I, H221Y, F227C, F227I, F227L, F227V, M230I,
L234I, P236L, and Y318F. The V106A, V106M, V108I, H221Y, F227C, M230I, P236L,
and Y318F substitutions conferred 3.4fold to 70-fold reductions in
susceptibility to doravirine. Y318F in combination with V106A, V106M, V108I,
and F227C conferred greater decreases in susceptibility to doravirine than
Y318F alone, which conferred a 10-fold reduction in susceptibility to
doravirine.
In Clinical Trials
Clinical Trial Results In Adults With No Antiretroviral
Treatment History
In the doravirine treatment arms of the DRIVE-FORWARD and
DRIVE-AHEAD trials (n=747) through Week 96, 13 subjects showed the emergence of
doravirine resistance-associated substitutions in their HIV among 36 (36%)
subjects in the resistance analysis subset (subjects with HIV-1 RNA greater
than 400 copies per mL at virologic failure or early study discontinuation and
having post-baseline resistance samples). Emergent doravirine
resistance-associated substitutions in RT included one or more of the
following: V90G/I, A98G, V106A, V106I, V106M/T, V108I, E138G, Y188L, H221Y,
P225H, P225L, P225P/S, F227C, F227C/R, Y318Y/F and Y318Y/S. Eight of 13 (62%)
subjects with emergent doravirine resistance-associated substitutions showed
doravirine phenotypic resistance and most of them had at least a 100-fold
reduction in doravirine susceptibility (range >95- to >211â⬓fold reduction
in doravirine susceptibility). The other 5 virologic failures who had only
amino acid mixtures of NNRTI resistance substitutions showed doravirine phenotypic
fold-changes of less than 2-fold. Of the 36 subjects in the resistance analysis
subset, 10 subjects (28%) developed genotypic and/or phenotypic resistance to
the other drugs (abacavir, emtricitabine, lamivudine, or tenofovir) in the
regimens of the DRIVE-FORWARD and DRIVE-AHEAD trials. The resistance-associated
substitutions that emerged were RT M41L (n=1), A62A/V (n=1), K65R (n=2), T69T/A
(n=1), V75V/I (n=1), and M184I or V (n=7).
In the DRV/r treatment arm of the DRIVE-FORWARD trial
(n=383) through Week 96, no subjects showed the emergence of darunavir
resistance-associated substitutions among 15 subjects with resistance data and
2 of the subjects had emergent genotypic or phenotypic resistance to lamivudine
or tenofovir. In the EFV/FTC/TDF treatment arm of the DRIVE-AHEAD trial (n=364)
through Week 96, 15 subjects showed the emergence of efavirenz
resistance-associated substitutions among 25 (60%) subjects in the resistance
analysis subset and genotypic resistance to emtricitabine or tenofovir
developed in 5 evaluable subjects; emergent resistance-associated substitutions
were RT K65R (n=1), D67G/K70E (n=1), L74V/V75M/V118I (n=1), M184I or V (n=5),
and K219K/E (n=1).
Clinical Trial Results In Virologically-Suppressed Adults
In the DRIVE-SHIFT clinical trial [see Clinical
Studies], there were 6 subjects in the immediate switch group (n=447) and 2
subjects in the delayed switch group (n=209) who met the protocol-defined
virologic failure criteria (confirmed HIV-1 RNA ≥ 50 copies/mL). Two of
the 6 virologic failure subjects in the immediate switch group had available
resistance data and neither developed detectable genotypic or phenotypic
resistance to doravirine, lamivudine, or tenofovir during treatment with
DELSTRIGO. One of the two virologic failure subjects in the delayed switch
group who had available resistance data developed the RT M184M/I substitution
and phenotypic resistance to emtricitabine and lamivudine during treatment with
their baseline regimen.
Cross-Resistance
Cross-resistance has been observed among NNRTIs.
Treatment-emergent doravirine resistance-associated substitutions can confer
cross-resistance to efavirenz, etravirine, nevirapine, and rilpivirine. Of the
8 virologic failures who developed doravirine phenotypic resistance, all had
phenotypic resistance to nevirapine, 6 had phenotypic resistance to efavirenz,
4 had phenotypic resistance to rilpivirine, and 3 had resistance to etravirine
in the Monogram PhenoSense assay. Of the 11 virologic failure subjects in
DRIVE-AHEAD phenotypically resistant to efavirenz, 2 (18%) had decreased
susceptibility to doravirine (18- and 36-fold).
The treatment-emergent doravirine resistance-associated
substitution Y318F did not confer reduced susceptibility to efavirenz, etravirine,
or rilpivirine.
A panel of 96 diverse clinical isolates containing NNRTI
resistance-associated substitutions was evaluated for susceptibility to
doravirine. Clinical isolates containing the Y188L substitution alone or in
combination with K103N or V106I, V106A in combination with G190A and F227L, or
E138K in combination with Y181C and M230L showed greater than 100-fold reduced
susceptibility to doravirine.
Clinical Studies
Clinical Trial Results In Adults With No Antiretroviral
Treatment History
The efficacy of PIFELTRO is based on the analyses of
96-week data from two randomized, multicenter, double-blind, active controlled
Phase 3 trials (DRIVE-FORWARD, NCT02275780 and DRIVE-AHEAD, NCT02403674) in
HIV-1 infected subjects with no antiretroviral treatment history (n=1494).
In DRIVE-FORWARD, 766 subjects were randomized and
received at least 1 dose of either PIFELTRO once daily or darunavir 800 mg +
ritonavir 100 mg (DRV+r) once daily each in combination with
emtricitabine/tenofovir DF (FTC/TDF) or abacavir/lamivudine (ABC/3TC) selected
by the investigator. At baseline, the median age of subjects was 33 years, 16%
were female, 27% were non-white, 4% had hepatitis B and/or C virus
co-infection, 10% had a history of AIDS, 20% had HIV-1 RNA greater than 100,000
copies/mL, 86% had CD4+ T-cell count greater than 200 cells/mm³, 13% received
ABC/3TC, and 87% received FTC/TDF; these characteristics were similar between
treatment groups.
In DRIVE-AHEAD, 728 subjects were randomized and received
at least 1 dose of either DELSTRIGO (DOR/3TC/TDF) or EFV 600 mg/FTC 200 mg/TDF
300 mg once daily. At baseline, the median age of subjects was 31 years, 15%
were female, 52% were non-white, 3% had hepatitis B or C co-infection, 14% had
a history of AIDS, 21% had HIV-1 RNA greater than 100,000 copies/mL, and 88%
had CD4+ T-cell count greater than 200 cells/mm³; these characteristics were
similar between treatment groups.
Week 96 outcomes for DRIVE-FORWARD and DRIVE-AHEAD are
provided in Table 9. Side-by-side tabulation is to simplify presentation;
direct comparisons across trials should not be made due to differing trial
designs.
In DRIVE-FORWARD, the mean CD4+ T-cell counts in the
PIFELTRO and DRV+r groups increased from baseline by 224 and 207 cells/mm³,
respectively.
In DRIVE-AHEAD, the mean CD4+ T-cell counts in the
DELSTRIGO and EFV/FTC/TDF groups increased from baseline by 238 and 223
cells/mm³, respectively.
Table 9: Virologic Outcome in DRIVE-FORWARD and
DRIVE-AHEAD at Week 96 in HIV-1 Adults with No Antiretroviral Treatment History
Outcome |
DRIVE-FORWARD |
DRIVE-AHEAD |
PIFELTRO + 2 NRTIs Once Daily
N=383 |
DRV+r + 2 NRTIs Once Daily
N=383 |
DELSTRIGO Once Daily
N=364 |
EFV/FTC/TDF Once Daily
N=364 |
HIV-1 RNA <50 copies/mL |
72% |
65% |
77% |
74% |
Treatment Differences (95% CI) * |
7.5% (1.0%, 14.1%) |
3.8% (-2.4%, 10.0%) |
HIV-1 RNA ≥ 50 copies/mL† |
17% |
20% |
15% |
12% |
No Virologic Data at Week 96 Window |
11% |
15% |
7% |
14% |
Discontinued study due to AE or Death‡ |
2% |
4% |
3% |
8% |
Discontinued study for Other Reasons§ |
7% |
9% |
4% |
5% |
On study but missing data in window |
2% |
3% |
1% |
1% |
Proportion (%) of Subjects With HIV-1 RNA <50 copies/mL at Week 96 by Baseline and Demographic Category |
Gender |
Male |
72% (N = 319) |
67% (N = 326) |
78% (N = 305) |
73% (N = 311) |
Female |
73% (N = 64) |
54% (N = 57) |
75% (N = 59) |
75% (N = 53) |
Race |
White |
78% (N = 280) |
68% (N = 280) |
80% (N = 176) |
74% (N = 170) |
Non-White |
58% (N = 103) |
57% (N = 102) |
76% (N = 188) |
74% (N = 194) |
Ethnicity¶ |
Hispanic or Latino |
76% (N = 93) |
63% (N = 86) |
81% (N = 126) |
77% (N = 119) |
Not Hispanic or Latino |
71% (N = 284) |
66% (N = 290) |
76% (N = 238) |
72% (N = 239) |
NRTI Background Therapy |
FTC/TDF |
71% (N = 333) |
64% (N = 335) |
- |
- |
ABC/3TC |
80% (N = 50) |
67% (N = 48) |
- |
- |
Baseline HIV-1 RNA (copies/mL) |
≤100,000 copies/mL |
75% (N = 300) |
66% (N = 309) |
80% (N = 291) |
77% (N = 282) |
>100,000 copies/mL |
61% (N = 83) |
59% (N = 73) |
67% (N = 73) |
62% (N = 82) |
CD4+ T-cell Count (cells/mm³) |
≤200 cells/mm³ |
62% (N = 42) |
51% (N = 67) |
59% (N = 44) |
70% (N = 46) |
>200 cells/mm³ |
74% (N = 341) |
68% (N = 316) |
80% (N = 320) |
74% (N = 318) |
Viral Subtype¶ |
Subtype B |
71% (N = 266) |
66% (N = 272) |
80% (N = 232) |
72% (N = 253) |
Subtype Non-B |
75% (N = 117) |
62% (N = 111) |
73% (N = 130) |
77% (N = 111) |
*The 95% CIs for the treatment differences were calculated
using stratum-adjusted Mantel-Haenszel method.
†Includes subjects who discontinued study drug or study before Week 96 for lack
or loss of efficacy and subjects with HIV-1 RNA equal to or above 50 copies/mL
in the Week 96 window.
‡Includes subjects who discontinued because of adverse event (AE) or death if
this resulted in no virologic data in the Week 96 window.
§Other Reasons include: lost to follow-up, non-compliance with study drug,
physician decision, pregnancy, protocol deviation, screen failure, withdrawal
by subject.
¶ Does not include subjects whose ethnicity or viral subtypes were unknown.
Note: NRTIs = FTC/3TC or ABC/3TC. |
Clinical Trial Results In Virologically-Suppressed
Adults
The efficacy of switching from
a baseline regimen consisting of two NRTIs in combination with a PI plus either
ritonavir or cobicistat, or elvitegravir plus cobicistat, or an NNRTI to
DELSTRIGO was evaluated in a randomized, open-label trial (DRIVE-SHIFT,
NCT02397096), in virologically-suppressed HIV-1 infected adults. Subjects must
have been virologically suppressed (HIV-1 RNA < 50 copies/mL) on their
baseline regimen for at least 6 months prior to trial entry, with no history of
virologic failure. Subjects were randomized to either switch to DELSTRIGO at
baseline (n = 447, Immediate Switch Group (ISG)), or stay on their baseline
regimen until Week 24, at which point they switched to DELSTRIGO (n = 223,
Delayed Switch Group (DSG)).
At baseline, the median age of subjects was 43 years, 16%
were female, and 24% were Non-White, 21% were of Hispanic or Latino ethnicity,
3% had hepatitis B and/or C virus co-infection, 17% had a history of AIDS, 96%
had CD4+ T-cell count greater than or equal to 200 cells/mm³, 70% were on a
regimen containing a PI plus ritonavir, 24% were on a regimen containing an
NNRTI, 6% were on a regimen containing elvitegravir plus cobicistat, and 1%
were on a regimen containing a PI plus cobicistat; these characteristics were
similar between treatment groups.
Virologic outcome results are
shown in Table 10.
Table 10: Virologic Outcomes
in DRIVE-SHIFT in HIV-1 Virologically-Suppressed Subjects Who Switched to
DELSTRIGO
Outcome |
DELSTRIGO Once Daily ISG Week 48
N=447 |
Baseline Regimen DSG Week 24
N=223 |
HIV-1 RNA ≥ 50 copies/mL* |
2% |
1% |
ISG-DSG, Difference (95% CI)†‡ |
0.7% (-1.3%, 2.6%) |
HIV-1 RNA <50 copies/mL |
91% |
95% |
No Virologic Data Within the Time Window |
8% |
4% |
Discontinued study due to AE or Death§ |
3% |
<1% |
Discontinued study for Other Reasons¶ |
4% |
4% |
On study but missing data in window |
0 |
0 |
Proportion (%) of Subjects With HIV-1 RNA <50 copies/mL by Baseline and Demographic Category |
Age (years) |
< 50 |
90% (N = 320) |
95% (N = 157) |
≥ 50 |
94% (N = 127) |
94% (N = 66) |
Gender |
Male |
91% (N = 372) |
94% (N = 194) |
Female |
91% (N = 75) |
100% (N = 29) |
Race |
White |
90% (N = 344) |
95% (N = 168) |
Non-White |
93% (N = 103) |
93% (N = 55) |
Ethnicity |
Hispanic or Latino |
88% (N = 99) |
91% (N = 45) |
Not Hispanic or Latino |
91% (N = 341) |
95% (N = 175) |
CD4+ T-cell Count (cells/mm³) |
<200 cells/mm³ |
85% (N = 13) |
75% (N = 4) |
≥200 cells/mm³ |
91% (N = 426) |
95% (N = 216) |
Baseline Regimen# |
PI plus either ritonavir or cobicistat |
90% (N=316) |
94% (N=156) |
elvitegravir plus cobicistat or NNRTI |
93% (N=131) |
96% (N=67) |
*Includes subjects who discontinued study drug or study
before Week 48 for ISG or before Week 24 for DSG for lack or loss of efficacy
and subjects with HIV-1 RNA ≥50 copies/mL in the Week 48 window for ISG
and in the Week 24 window for DSG.
†The 95% CI for the treatment difference was calculated using stratum-adjusted
Mantel-Haenszel method.
‡Assessed using a non-inferiority margin of 4%.
§Includes subjects who discontinued because of adverse event (AE) or death if
this resulted in no virologic data on treatment during the specified window.
¶Other reasons include: lost to follow-up, non-compliance with study drug,
physician decision, protocol deviation, withdrawal by subject.
#Baseline Regimen = PI plus either ritonavir or cobicistat (specifically
atazanavir, darunavir, or lopinavir), or elvitegravir plus cobicistat, or NNRTI
(specifically efavirenz, nevirapine, or rilpivirine), each administered with
two NRTIs. |