Clinical Pharmacology for Veklury
Mechanism Of Action
Remdesivir is an antiviral drug with activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [see Microbiology].
Pharmacodynamics
Remdesivir and metabolites exposure-response relationships and the time course of pharmacodynamics response are unknown.
Pharmacokinetics
The pharmacokinetic (PK) properties of remdesivir and metabolites are provided in Table 14. The multiple dose PK parameters of remdesivir and metabolites in adults with COVID-19 are provided in Table 15.
Table 14 : Pharmacokinetic Properties of Remdesivir and Metabolites (GS-441524 and GSÂ704277)
|
Remdesivir |
GS-441524 |
GS-704277 |
| Absorption |
| Tmax (h)a |
0.67-0.68 |
1.51-2.00 |
0.75-0.75 |
| Distribution |
| % bound to human plasma proteins |
88-93.6b |
2 |
1 |
| Blood-to-plasma ratio |
0.68-1.0 |
1.19 |
0.56 |
| Elimination |
| t½ (h)c |
1 |
27 |
1.3 |
| Metabolism |
| Metabolic pathway(s) |
CES1 (80%) Cathepsin A (10%) CYP3A (10%) |
Not significantly metabolized |
HINT1 |
| Excretion |
| Major route of elimination |
Metabolism |
Glomerular filtration and active tubular secretion |
Metabolism |
| % of dose excreted in urined |
10 |
49 |
2.9 |
| % of dose excreted in fecesd |
ND |
0.5 |
ND |
ND=not detected
a Remdesivir administered as a 30-minute IV infusion (Study GS-US-399-5505); range of median observed on Day 1 and Day 5 or 10.
b Range of protein binding for remdesivir from 2 independent experiments show no evidence of concentration-dependent protein binding for remdesivir.
c Median (Study GS-US-399-4231).
d Mean (Study GS-US-399-4231). |
Table 15 : Multiple Dose PK Parametersa of Remdesivir and Metabolites (GS-441524 and GSÂ704277) Following IV Administration of VEKLURY 100 mg to Adults with COVID-19
| Parameter Meanb (95% CI) |
Remdesivir |
GS-441524 |
GS-704277 |
| Cmax (nanogram per mL) |
2700
(2440, 2990) |
143
(135, 152) |
198
(180, 218) |
| AUCtau (nanogram•h per mL) |
1710
(1480, 1980) |
2410
(2250, 2580) |
392
(348, 442) |
| Ctrough (nanogram per mL) |
ND |
61.5
(56.5, 66.8) |
ND |
CI=Confidence Interval; ND=Not detectable (at 24 hours post-dose)
a Population PK estimates for 30-minute IV infusion of remdesivir for 3 days (Study GS-US-540-9012, n=147).
b Geometric mean estimates. |
Specific Populations
Pharmacokinetic differences based on sex, race, age, and renal function on the exposures of remdesivir were evaluated using population pharmacokinetic analysis. Sex and race did not affect the pharmacokinetics of remdesivir and its metabolites (GS-441524 and GS-704277).
Pregnant Individuals
The pharmacokinetics of remdesivir and its circulating metabolites (GS-441524 and GS-704277) were evaluated in pregnant individuals with COVID-19. Exposures (AUCtau, Cmax, and Ctau) of remdesivir and its circulating metabolites during pregnancy were similar to those in non-pregnant individuals (see Table 16).
Table 16 : Multiple Dose PK Parametersa of Remdesivir and Metabolites (GS-441524 and GSÂ704277) Following Intravenous Administration of VEKLURY to Pregnant and Non-Pregnant Individuals with COVID-19
| Parameter Meanb (90% CI) |
Pregnant Individuals
(N=21) |
Non-Pregnant Individuals
(N=22) |
| Remdesivir |
| Cmax (nanogram per mL) |
1360 (978, 1890) |
1240 (891, 1720) |
| AUCtau (nanogram•h per mL) |
1250
(916, 1700)c |
1300
(1070, 1590)d |
| GS-441524 |
| Cmax (nanogram per mL) |
113 (102, 126) |
121 (108, 136) |
| AUCtau (nanogram•h per mL) |
1840
(1630, 2070)e |
2050
(1780, 2350)f |
| Ctau (nanogram per mL) |
51.6 (44.7, 59.6)e |
57.1 (48.7, 66.9)f |
| GS-704277 |
| Cmax (nanogram per mL) |
217 (187, 252) |
213 (188, 240) |
| AUCtau (nanogram•h per mL) |
454 (406, 508)e |
437 (384, 497) |
CI=Confidence Interval
a Study CO-US-590-5961 (IMPAACT).
b Geometric mean estimates.
c N=18
d N=17
e N=20
f N=21 |
Patients With Renal Impairment
The pharmacokinetics of remdesivir and its metabolites (GS-441524 and GS-704277) and excipient SBECD were evaluated in healthy subjects, those with mild (eGFR 60-89 mL/minute/1.73m²), moderate (eGFR 30-59 mL/minute/1.73m²), severe (eGFR 15-29 mL/minute/1.73m²) renal impairment, or kidney failure (eGFR <15 mL/minute/1.73m²) on dialysis or not on dialysis following a single dose of up to 100 mg of VEKLURY (see Table 16); and in COVID-19 patients with severely reduced kidney function (AKI [defined as a 50% increase in serum creatinine within a 48-hour period that was sustained for ≥6 hours despite supportive care]; CKD [eGFR <30 mL/minute/1.73m²]; or ESRD [eGFR <15 mL/minute/1.73m²] requiring hemodialysis) receiving VEKLURY 200 mg loading dose on Day 1 followed by 100 mg from Day 2 to Day 5 (see Table 17). Pharmacokinetic exposures of remdesivir were not affected by renal function or timing of VEKLURY administration around dialysis.
Exposures of GS-441524, GS-704277, and SBECD were up to 7.9-fold, 2.8-fold, and 21-fold higher, respectively, in those with renal impairment compared to those with normal renal function (see Table 17 and Table 18). These changes are not considered to be clinically significant [see ADVERSE REACTIONS Â and Use In Specific Populations].
Remdesivir was not efficiently removed through hemodialysis. Average hemodialysis clearance of GS-441524 and GS-704277 was 149 mL/minute and 92.6 mL/minute, respectively.
Table 17 : Comparison of PK Parametersa of Remdesivir and Metabolites (GS-441524 and GS-704277) Following IV Administration of Single Dose VEKLURY to Adults with Renal Impairmentb as Compared to Adults with Normal Renal Function
| Mean Ratio (90% CI)c |
60-89 mL per minuteb
N=10 |
30-59 mL per minuteb
N=10 |
15-29 mL per minuteb
N=10 |
<15 mL per minuteb |
Pre- hemodialysis
N=6 |
Post- hemodialysis
N=6 |
No dialysis
N=3 |
| Remdesivir |
| Cmax |
0.96
(0.71, 1.31) |
1.20
(1.01, 1.42) |
0.97
(0.83, 1.13) |
0.89
(0.67, 1.18) |
1.13
(0.79, 1.60) |
0.94
(0.65, 1.35) |
| AUCinf |
1.00
(0.75, 1.32) |
1.22
(0.98, 1.52) |
0.94
(0.83, 1.07) |
0.80
(0.59, 1.08) |
1.08
(0.72, 1.63) |
0.89
(0.55, 1.43) |
| GS-441524 |
| Cmax |
1.07
(0.90, 1.26) |
1.44
(1.13, 1.85) |
1.68
(1.28, 2.20) |
2.27
(1.72, 2.99) |
3.07
(2.21, 4.26) |
3.00
(2.63, 3.42) |
| AUCinf |
1.19
(0.97, 1.47) |
2.02
(1.57, 2.62) |
3.26
(2.39, 4.46) |
4.97
(3.65, 6.77) |
6.22
(4.44, 8.71) |
7.87
(6.49, 9.53) |
| GS-704277 |
| Cmax |
2.25
(1.20, 4.20) |
1.83
(1.34, 2.49) |
1.27
(0.96, 1.68) |
1.43
(1.00, 2.05) |
1.23
(0.84, 1.80) |
1.76
(1.19, 2.61) |
| AUCinf |
1.39
(1.13, 1.71) |
2.01
(1.48, 2.73) |
1.78
(1.27, 2.49) |
2.18
(1.61, 2.95) |
2.06
(1.42, 2.97) |
2.81
(1.79, 4.43) |
CI=Confidence Interval
a Exposures were estimated using noncompartmental analysis from a dedicated Phase 1 renal impairment Study GSÂUS-540-9015; single doses up to 100 mg were administered; each subject with renal impairment had a matched control participant enrolled with normal renal function (eGFR ≥90 mL/minute/1.73m²), same sex, and similar BMI (± 20%) and age (± 10 years).
b. eGFR was calculated using Modification of Diet in Renal Disease equation and values represent mL/minute/1.73m². c. No effect=1.0 (0.5-2.0) |
Table 18 : Comparison of PK Parameters of Remdesivir and Metabolites (GS-441524 andGS-704277) Following IV Administration of VEKLURY (200 mg on Day 1 Followed by 100 mg Daily on Days 2-5) in Adults with COVID-19 witha or withoutb Severely Reduced Kidney Functionc
| Mean Ratio (90% CI)d |
Remdesivir |
GS-441524 |
GS-704277 |
| Cmax |
1.39 (1.25, 1.54) |
4.98 (4.61, 5.38) |
1.84 (1.63, 2.08) |
| AUCtau |
1.79 (1.59, 2.01) |
6.59 (6.05, 7.18) |
3.94 (3.50, 4.43) |
| Ctau |
ND |
5.82 (5.25, 6.45) |
ND |
CI=Confidence Interval; ND=Not detectable (at 24 hours post-dose)
a Population PK estimates for 30-minute IV infusion of remdesivir for 5 days (Study GS-US-540-5912, n=90).
b Population PK estimates for 30-minute IV infusion of remdesivir for 3 days (Study GS-US-540-9012, n=148).
c AKI (defined as a 50% increase in serum creatinine within a 48-hour period that was sustained for ≥6 hours despite supportive care); CKD (eGFR <30 mL/minute/1.73m²); or ESRD (eGFR <15 mL/minute/1.73m²) requiring hemodialysis.
d No effect=1.0 (0.5-2.0) |
Patients With Hepatic Impairment
The pharmacokinetics of remdesivir and GS-441524 were evaluated in healthy subjects and those with moderate or severe hepatic impairment (Child-Pugh Class B or C) following a single dose of 100 mg of VEKLURY (see Table 19). Relative to subjects with normal hepatic function, mean exposures (AUCinf, Cmax) of remdesivir and GS-441524 were similar in subjects with moderate hepatic impairment and higher in subjects with severe hepatic impairment. The exposure differences in subjects with severe hepatic impairment are not considered to be clinically significant [see Use In Specific Populations].
Table 19 : Comparison of PK Parameters of Remdesivir and GS-441524 Following IV Administration of Single Dose VEKLURY to Adults with Hepatic Impairment as Compared to Adults with Normal Hepatic Function
| Mean Ratio (90% CI)a |
Moderate Hepatic Impairment
N=10 |
Severe Hepatic Impairment
N=6 |
| Remdesivir |
| AUCinf |
1.21 (0.87, 1.67) |
1.56 (1.20, 2.03) |
| Cmax |
1.10 (0.75, 1.60) |
1.03 (0.70, 1.51) |
| Unbound AUCinf |
1.15 (0.86, 1.54) |
2.44 (1.93, 3.08) |
| Unbound Cmax |
1.04 (0.73, 1.48) |
1.57 (1.08, 2.29) |
| GS-441524 |
| AUCinf |
0.90 (0.69, 1.17) |
1.31 (0.93, 1.84) |
| Cmax |
1.09 (0.86, 1.38) |
1.48 (1.17, 1.86) |
| C24 |
0.93 (0.69, 1.24) |
1.16 (0.76, 1.77) |
CI=Confidence Interval
a No effect=1.0 (0.5-2.0) |
Pediatric Patients
Population pharmacokinetic models for remdesivir and its circulating metabolites (GS-441524 and GS-704277), developed using pooled data from studies in healthy subjects and in adult and pediatric patients with COVID-19, were used to estimate pharmacokinetic exposures in pediatric patients aged from birth to <18 years and weighing ≥1.5 kg (Study 5823). Geometric mean estimated exposures (AUCtau, Cmax, and Ctau) for patients ≥28 days to <18 years old and weighing ≥3 kg (Cohorts 1-4 and 8, n=50) at the doses administered were 33% to 130% higher for remdesivir, 3% lower to 60% higher for GS-441524, and 32% to 124% higher for GS-704277 as compared to those in adult patients with COVID-19; however, the increases were not considered clinically significant. Individual estimated exposures (AUCtau, Cmax, and Ctau) for patients 14 to <28 days old, GA >37 weeks, and weighing ≥2.5 kg (Cohort 5, n=3); patients <14 days old, GA >37 weeks, and weighing ≥2.5 kg at birth (Cohort 6, n=1); and patients <56 days old, GA ≤37 weeks, and weighing ≥1.5 kg at birth (Cohort 7, n=1) at the doses administered were higher for remdesivir, GS-441524, and GS-704277 as compared to median exposures in adult patients with COVID-19; however, the increases were not considered clinically significant. As limited PK data were available in Cohorts 5-7, additional analyses were conducted using a simulated population.
Using age and weight distributions from pediatric growth charts, simulated population datasets were created for Cohorts 5-6. Modeling and simulation incorporating maturation functions that account for renal function and drug metabolizing enzyme ontogeny with age were used to predict exposures for subjects <28 days old, GA >37 weeks, and weighing ≥1.5 kg and subjects ≥28 days old and weighing ≥1.5 to <3 kg. Predicted geometric mean exposures (AUCtau, Cmax, and Ctau) at the recommended doses were 10% to 96% higher for remdesivir, 15% lower to 3% higher for GS-441524, and 14% lower to 132% higher for GS-704277 as compared to those in adult patients with COVID-19; however, changes in exposure were not considered clinically significant. Results of simulated population led to the recommended dosing regimen as they more closely align with adult exposures compared to the doses studied.
Plasma exposures of excipient SBECD were generally similar for all pediatric patients at the doses administered in Study GS-US-540-5823 and were similar compared to adults with normal renal function, although data are very limited [see Use In Specific Populations].
The multiple dose PK parameters of remdesivir and metabolites in pediatric patients with COVID-19 in Cohorts 1-4 and 8 are provided in Table 20.
Table 20 : Multiple Dose PK Parametersa of Remdesivir and Metabolites (GS-441524 and GSÂ704277) Following Intravenous Administration of VEKLURY 100 mg (Cohorts 1 and 8) or 2.5 mg/kg (Cohorts 2-4) to Pediatric Patients with COVID-19
| Parameter Meanb (95% CI) |
Cohort 1 |
Cohort 8 |
Cohort 2 |
Cohort 3 |
Cohort 4 |
12 to <18 Years and Weighing ≥40 kg
(N=12) |
<12 Years and Weighing ≥40 kg
(N=5) |
28 Days to <18 Years and Weighing 20 to <40 kg
(N=12) |
28 Days to <18 Years and Weighing 12 to <20 kg
(N=11) |
28 Days to <18 Years and Weighing 3 to <12 kg
(N=10) |
| Remdesivir |
Cmax
(nanogram per mL) |
3890
(3110, 4870) |
3920
(2260, 6820) |
5730
(4660, 7050) |
5570
(4250, 7300) |
4870
(3750, 6340) |
AUCtau
(nanogram•h per mL) |
2470
(1920, 3160) |
2270
(1200, 4310) |
3510
(2560, 4820) |
3930
(2140, 7210) |
2910
(1880, 4510) |
| GS-441524 |
Cmax
(nanogram per mL) |
196
(122, 315) |
163
(57.6, 461) |
183
(129, 260) |
171
(130, 223) |
205
(174, 241) |
AUCtau
(nanogram•h per mL) |
3430
(1980, 5920) |
2640
(767, 9100) |
2370
(1500, 3740) |
2410
(1740, 3340) |
2850
(2290, 3540) |
Ctau
(nanogram per mL) |
98.5
(59.1, 164) |
76.2
(23.9, 243) |
59.9
(34.2, 105) |
68.9
(47.4, 100) |
79.7
(59.5, 107) |
| GS-704277 |
Cmax
(nanogram per mL) |
308
(211, 450) |
266
(137, 514) |
419
(306, 575) |
444
(335, 587) |
385
(294, 504) |
AUCtau
(nanogram•h per mL) |
819
(474, 1420) |
518
(192, 1400) |
753
(542, 1050) |
733
(504, 1060) |
687
(484, 973) |
CI=Confidence Interval
a Population PK estimates for 30-minutes IV infusion of remdesivir for up to 10 days (Study GS-US-540-5823).
b Geometric mean estimates. |
Drug Interaction Studies
In vitro, remdesivir is a substrate for enzymes CYP3A, carboxylesterase 1 (CES1), and cathepsin A (CatA) and OATP1B1 and P-gp transporters; GS-704277 is a substrate for OATP1B1 and OATP1B3. In vitro, remdesivir is an inhibitor of CYP3A, UGT1A1, OATP1B1, OATP1B3, and MATE1; however, no clinically significant effects on substrates of UGT1A1 or MATE1 are expected. No inhibitory interactions were identified for GS-704277 or GS-441524 in vitro.
Remdesivir is not a substrate for CYP1A1, 1A2, 2B6, 2C9, 2C19, or OATP1B3. GS-704277 and GS441524 are not substrates for CYP1A1, 1A2, 2B6, 2C8, 2C9, 2D6, or 3A5. GS-441524 is also not a substrate for CYP2C19 or 3A4. GS-704277 and GS-441524 are not substrates for OAT1, OAT3, OCT1, OCT2, MATE1, or MATE2k. GS-441524 is also not a substrate for OATP1B1 or OATP1B3.
Drug-drug interaction studies were conducted with VEKLURY. Table 21 summarizes the pharmacokinetic effects of other drugs on remdesivir and metabolites GS-704277 and GS-441524. Table 22 summarizes the effects of remdesivir on the pharmacokinetics of other drugs.
Table 21 : Effect of Other Drugs on Remdesivir and Metabolites GS-704277 and GS-441524
| Coadministered Drug |
Dose of Coadministered Drug (mg) |
Remdesivir Dose (mg) |
N |
Mean Ratio (90% CI) of Remdesivir, GS-704277, and GS-441524 PK With/Without Coadministered Drug No Effect = 1.00 (0.70-1.43) |
|
Cmax |
AUCinf |
C24 |
| Cyclosporin Aa |
400 single dose |
100 single dose |
9 |
remdesivir |
1.49
(1.38- 1.60) |
1.89
(1.77- 2.02) |
- |
| GS-704277 |
2.51
(2.26- 2.78) |
2.97
(2.75- 3.20) |
- |
| GS-441524 |
1.17
(1.12- 1.22) |
1.03
(0.99- 1.08) |
1.02
(0.95- 1.10) |
| Carbamazepinea |
300 twice daily |
100 single dose |
8 |
remdesivir |
0.87
(0.78- 0.97) |
0.92
(0.83- 1.02) |
- |
| GS-704277 |
0.96
(0.84- 1.10) |
0.98
(0.92- 1.05) |
- |
| GS-441524 |
0.97
(0.88- 1.07) |
0.83
(0.78- 0.89) |
0.71
(0.64- 0.78) |
CI=confidence interval
a Interaction study conducted in healthy volunteers. |
Table 22 : Effect of Remdesivir on the Pharmacokinetics of Other Drugs
| Coadministered Drug |
Dose of Coadministered Drug (mg) |
Remdesivir Dose (mg) |
N |
Mean Ratio (90% CI) of Coadministered Drug PK With/Without RemdesivirNo Effect = 1.00 (0.80-1.25) |
| Cmax |
AUCinf |
| Midazolama |
2.5 single dose |
200 single dose |
19 |
1.29
(1.19-1.41) |
1.20
(1.14-1.26) |
| Midazolama |
2.5 single dose |
200 single dose followed by 100 once daily (10 doses)b |
14 |
1.45
(1.23-1.70) |
1.30
(1.16-1.45) |
| Pitavastatina |
2 single dose |
200 single dose |
20 |
1.05
(0.92-1.20) |
1.17
(1.09-1.24) |
CI=confidence interval
a Interaction study conducted in healthy volunteers.
bMidazolam administered with last dose of remdesivir. |
Microbiology
Mechanism Of Action
Remdesivir is an inhibitor of the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), which is essential for viral replication. Remdesivir is an adenosine nucleotide prodrug that distributes into cells where it is metabolized to a nucleoside monophosphate intermediate by carboxyesterase 1 and/or cathepsin A, depending upon the cell type. The nucleoside monophosphate is subsequently phosphorylated by cellular kinases to form the pharmacologically active nucleoside triphosphate metabolite (GS-443902). Remdesivir triphosphate (RDV-TP) acts as an analog of adenosine triphosphate (ATP) and competes with high selectivity (3.65-fold) over the natural ATP substrate for incorporation into nascent RNA chains by the SARS-CoV-2 RdRp, which results in delayed chain termination (position i+3) during replication of the viral RNA. In a biochemical assay assessing RDVÂTP incorporation by the MERS-CoV RdRp complex, RDV-TP inhibited RNA synthesis with an IC50 value of 0.032 μM. RDV-TP can also inhibit viral RNA synthesis following its incorporation into the template viral RNA as a result of read-through by the viral polymerase that may occur at higher nucleotide concentrations. When remdesivir nucleotide is present in the viral RNA template, the efficiency of incorporation of the complementary natural nucleotide is compromised, thereby inhibiting viral RNA synthesis. Remdesivir triphosphate is a weak inhibitor of mammalian DNA and RNA polymerases, including human mitochondrial RNA polymerase.
Antiviral Activity
In Cell Culture
Remdesivir exhibited cell culture antiviral activity against a clinical isolate of SARS-CoV-2 in primary human airway epithelial (HAE) cells with a 50% effective concentration (EC50) of 9.9 nM after 48 hours of treatment. Remdesivir inhibited the replication of SARS-CoV-2 in the continuous human lung epithelial cell lines Calu-3 and A549-hACE2 with EC50 values of 280 nM after 72 hours of treatment and 115 nM after 48 hours of treatment, respectively.
Remdesivir EC50 values for SARS-CoV-2 in A549-hACE2 cells were not different when combined with chloroquine phosphate or hydroxychloroquine sulfate at concentrations up to 2.5 μM. In a separate study, the antiviral activity of remdesivir was antagonized by chloroquine phosphate in a dose-dependent manner when the two drugs were co-incubated at clinically relevant concentrations in HEp-2 cells infected with respiratory syncytial virus (RSV). Higher remdesivir EC50 values were observed with increasing concentrations of chloroquine phosphate. Increasing concentrations of chloroquine phosphate or hydroxychloroquine sulfate reduced formation of remdesivir triphosphate in A549-hACE2, HEp-2, and normal human bronchial epithelial cells.
Based on cell culture susceptibility testing by virus yield reduction assay and/or N protein ELISA assay, remdesivir retained similar antiviral activity against clinical isolates of SARS-CoV-2 variants compared to an earlier lineage SARS-CoV-2 (lineage A) isolate, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), Epsilon (B.1.429), Zeta (P.2), Iota (B.1.526), Kappa (B.1.617.1), Lambda (C.37), and Omicron variants (including B.1.1.529/BA.1, BA.2, BA.2.12.1, BA.2.75, BA.4, BA.4.6, BA.5, BF.5, BF.7, BQ.1, BQ.1.1, CH.1.1, EG.1.2, EG.5.1, FL.22, XBB, XBB.1.5, XBB.1.16, XBB.2.3.2, and XBF). For these variants, the EC50 fold change values ranged between 0.2 and 2.3 compared to an earlier lineage SARS-CoV-2 (lineage A) isolate. Using the SARS-CoV-2 replicon system, remdesivir retained similar antiviral activity against Omicron subvariants BA.2.86 and XBB.1.9.2 compared to the wildtype reference replicon (lineage B).
In Clinical Trials
SARS-CoV-2 RNA shedding results from GS-US-540-5776 (ACTT-1) indicate that remdesivir does not significantly reduce the amount of detectable SARS-CoV-2 RNA in oropharyngeal or nasopharyngeal swabs or plasma samples in hospitalized patients compared to placebo, and SARSÂCoV-2 RNA shedding results from GS-US-540-9012 indicate that remdesivir does not significantly reduce the amount of detectable SARS-CoV-2 RNA in nasopharyngeal swabs in non-hospitalized patients compared to placebo.
Resistance
In Cell Culture
SARS-CoV-2 isolates with reduced susceptibility to remdesivir have been selected in cell culture. In a selection with GS-441524, the parent nucleoside of remdesivir, virus pools emerged expressing amino acid substitutions at V166A, N198S, S759A, V792I, C799F, and C799R in the viral RdRp (nsp12). When these substitutions were individually introduced into a wild-type recombinant virus by site-directed mutagenesis, 1.7-to 3.5-fold reductions in susceptibility to remdesivir were observed. In a cell culture resistance selection experiment with remdesivir, nsp12 amino acid substitution E802D emerged, resulting in a 1.4-to 2.5-fold reduction in susceptibility to remdesivir. In another selection with remdesivir using a SARS-CoV-2 isolate containing the P323L substitution in the viral polymerase, a single amino acid substitution at V166L emerged. Recombinant SARS-CoV-2 with substitutions at P323L alone or P323L+V166L in combination exhibited 1.3-and 1.5-fold reductions in remdesivir susceptibility, respectively.
Cell culture resistance profiling of remdesivir using the rodent CoV murine hepatitis virus identified two substitutions (F476L and V553L) in the viral RdRp (nsp12) at residues conserved across CoVs. Introduction of the corresponding substitutions (F480L and V557L) into SARS-CoV resulted in 6-fold reduction in susceptibility to remdesivir in cell culture and attenuated SARS-CoV pathogenesis in a mouse model. When individually introduced into a SARS-CoV-2 recombinant virus, the corresponding substitutions at F480L and V557L each conferred 2-fold reduced susceptibility to remdesivir.
In Clinical Studies
In a literature publication, the SARS-CoV-2 nsp12 E802D substitution previously identified in a resistance selection experiment emerged in one individual treated with remdesivir. The E802D substitution resulted in a 1.4-to 2.5-fold increase in the remdesivir EC50 value.
In Study CO-US-540-5776 (ACTT-1), among 61 subjects with baseline and post-baseline sequencing data available, the rate of emerging substitutions in the viral RdRp (nsp12) was similar in subjects treated with VEKLURY compared to placebo. Two subjects treated with VEKLURY had an emergent substitution previously identified in resistance selection experiments (nsp12 V792I in one and C799F in the other). These substitutions are associated with 2.2-and 2.5-fold decreases in remdesivir susceptibility, respectively, based on assessments of clinical isolates. In one subject treated with VEKLURY, nsp12 V792F emerged at low frequency and was associated with a 1.8-fold decrease in remdesivir susceptibility.
In Study GS-US-540-5773, among 19 subjects treated with VEKLURY with baseline and post-baseline sequencing data available, the V792F substitution in viral RdRp (nsp12) emerged at low frequency in one subject.
In Study GS-US-540-9012, among 244 subjects with baseline and post-baseline sequencing data available, the rate of emerging substitutions in the viral RdRp (nsp12) was similar in subjects treated with VEKLURY compared to placebo. In one subject treated with VEKLURY, one substitution in the RdRp (nsp12 A376V) emerged and was associated with a 12.6-fold decrease in remdesivir susceptibility in a subgenomic replicon assay. This subject was not hospitalized and showed alleviation of all baseline symptoms, except loss of taste and smell, prior to or on Day 14.
In Study GS-US-540-5912, among 60 subjects with baseline and post-baseline sequencing data available, substitutions in the viral RdRp (nsp12) emerged in 8 subjects treated with VEKLURY. In 4 subjects treated with VEKLURY, three substitutions in the RdRp (nsp12 E136V, M794I, or C799F) emerged and were associated with 2.9-, 2.9-, and 3.4-fold reduced susceptibility to remdesivir in a subgenomic replicon assay.
In Study GS-US-540-5823, among pediatric subjects with baseline and post-baseline sequencing data available, treatment-emergent substitutions in the viral RdRp (nsp12) were observed in 3 of 27 subjects treated with VEKLURY and were evaluated for susceptibility to remdesivir. In one subject, two substitutions (nsp12 substitutions V166L and V792I) emerged and were associated with 1.85Âand 3.6-fold decreases in remdesivir susceptibility relative to reference, respectively. This subject was hospitalized at baseline, recovered from COVID-19, and was released from the hospital on Day 13. None of the substitutions observed in any of the other genes (nsp9-10, nsp13-14) encoding for proteins of the viral replication-transcription complex have been associated with reduced susceptibility to remdesivir.
The relationship between the level of reduced susceptibility to remdesivir observed in subgenomic replicon assays and the inhibition of SARS-CoV-2 replication by remdesivir in humans has not been fully established.
Animal Toxicology And/Or Pharmacology
Intravenous administration (slow bolus) of remdesivir to male rhesus monkeys at dosage levels of 5, 10, and 20 mg/kg/day for 7 days resulted, at all dose levels, in increased mean urea nitrogen and increased mean creatinine, renal tubular atrophy, and basophilia and casts.
Intravenous administration (slow bolus) of remdesivir to rats at dosage levels of ≥3 mg/kg/day for up to 4 weeks resulted in findings indicative of kidney injury and/or dysfunction.
Kidney-related effects in rats and monkeys were observed at exposures of the predominant circulating metabolite (GS-441524) that are lower than the exposure in humans at the RHD.
Clinical Studies
Description Of Clinical Trials
The efficacy and safety of VEKLURY were evaluated in the trials summarized in Table 23.
Table 23 : Trials Conducted with VEKLURY in Subjects with COVID-19
| Trial |
Population |
Trial Arms (N) |
Timepoint |
| NIAID ACTT-1a (NCT04280705) |
Hospitalized with mild/moderate and severe COVID-19 |
VEKLURY 10 Days (532) Placebo (516) |
29 Days after Randomization |
| GS-US-540-5773b (NCT04292899) |
Hospitalized with severe COVID-19 |
VEKLURY 5 Days (200) VEKLURY 10 Days (197) |
Day 14 |
| GS-US-540-5774b (NCT04292730) |
Hospitalized with moderate COVID-19 |
VEKLURY 5 Days (191) VEKLURY 10 Days (193) Standard of care (200) |
Day 11 |
| GS-US-540-9012a (NCT04501952) |
Non-hospitalized with mild-to-moderate COVID-19 and at high risk for progression to severe disease |
VEKLURY 3 Days (279) Placebo (283) |
Day 28 |
| GS-US-540-5823 (Cohorts 1-8)c (NCT04431453) |
Hospitalized pediatric subjects from birth to <18 years of age and weighing at least 1.5 kg with COVID-19 |
VEKLURY up to 10 Days (58) |
Day 10 |
COVID-19: coronavirus disease 2019
a Randomized, double-blind, placebo-controlled trial.
b Randomized, open-label trial.
c Open-label trial, descriptive outcome analyses. |
NIAID ACTT-1 Study In Hospitalized Subjects With Mild/Moderate And Severe COVID-19
A randomized, double-blind, placebo-controlled clinical trial (ACTT-1) of hospitalized adult subjects with confirmed SARS-CoV-2 infection and mild, moderate, or severe COVID-19 compared treatment with VEKLURY for 10 days (n=541) with placebo (n=521). Mild/moderate disease was defined as SpO2 >94% and respiratory rate <24 breaths/minute without supplemental oxygen; severe disease was defined as an SpO2 ≤94% on room air, a respiratory rate ≥24 breaths/minute, an oxygen requirement, or a requirement for mechanical ventilation. Subjects had to have at least one of the following to be enrolled in the trial: radiographic infiltrates by imaging, SpO2 ≤94% on room air, a requirement for supplemental oxygen, or a requirement for mechanical ventilation. Subjects treated with VEKLURY received 200 mg on Day 1 and 100 mg once daily on subsequent days, for 10 days of treatment via intravenous infusion. Treatment with VEKLURY was stopped in subjects who were discharged from the hospital prior to the completion of 10 days of treatment.
At baseline, mean age was 59 years (with 36% of subjects aged 65 or older); 64% of subjects were male, 53% were White, 21% were Black, and 13% were Asian; 24% were Hispanic or Latino; 105 subjects had mild/moderate disease (10% in both treatment groups); 957 subjects had severe disease (90% in both treatment groups). Subjects in this trial were unvaccinated. A total of 285 subjects (27%) (n=131 received VEKLURY) were on invasive mechanical ventilation or ECMO. The most common comorbidities were hypertension (51%), obesity (45%), and type 2 diabetes mellitus (31%); the distribution of comorbidities was similar between the two treatment groups.
The primary clinical endpoint was time to recovery within 29 days after randomization. Recovery was defined as discharged from the hospital without limitations on activities, discharged from the hospital with limitations on activities and/or requiring home oxygen, or hospitalized but not requiring supplemental oxygen and no longer requiring ongoing medical care. The median time to recovery was 10 days in the VEKLURY group compared to 15 days in the placebo group (recovery rate ratio 1.29 [95% CI 1.12 to 1.49], p<0.001). Among subjects with mild/moderate disease at enrollment (n=105), the median time to recovery was 5 days in both the VEKLURY and placebo groups (recovery rate ratio 1.22 [95% CI 0.82 to 1.81]). Among subjects with severe disease at enrollment (n=957), the median time to recovery was 11 days in the VEKLURY group compared to 18 days in the placebo group (recovery rate ratio 1.31 [95% CI 1.12 to 1.52]).
A key secondary endpoint was clinical status on Day 15 assessed on an 8-point ordinal scale consisting of the following categories:
- not hospitalized, no limitations on activities;
- not hospitalized, limitation on activities and/or requiring home oxygen;
- hospitalized, not requiring supplemental oxygen -no longer requires ongoing medical care;
- hospitalized, not requiring supplemental oxygen -requiring ongoing medical care (COVID-19 related or otherwise);
- hospitalized, requiring supplemental oxygen;
- hospitalized, on noninvasive ventilation or high-flow oxygen devices;
- hospitalized, on invasive mechanical ventilation or ECMO; and
- death.
Overall, the odds of improvement in the ordinal scale were higher in the VEKLURY group at Day 15 when compared to the placebo group (odds ratio 1.54 [95% CI 1.25 to 1.91]).
Overall, 29-day mortality was 11% for the VEKLURY group vs 15% for the placebo group (hazard ratio 0.73 [95% CI 0.52 to 1.03]).
Study GS-US-540-5773 In Hospitalized Subjects With Severe COVID-19
A randomized, open-label multi-center clinical trial (Study 5773) in adult subjects with confirmed SARS-CoV-2 infection, an SpO2 of ≤94% on room air, and radiological evidence of pneumonia compared 200 subjects who received VEKLURY for 5 days with 197 subjects who received VEKLURY for 10 days. Treatment with VEKLURY was stopped in subjects who were discharged from the hospital prior to completion of their protocol-defined duration of treatment. Subjects on mechanical ventilation at screening were excluded. All subjects received 200 mg of VEKLURY on Day 1 and 100 mg once daily on subsequent days via intravenous infusion, plus standard of care.
At baseline, the median age of subjects was 61 years (range, 20 to 98 years); 64% were male, 75% were White, 12% were Black, and 12% were Asian; 22% were Hispanic or Latino. More subjects in the 10-day group than the 5-day group required invasive mechanical ventilation or ECMO (5% vs 2%), or high-flow oxygen support (30% vs 25%), at baseline. Subjects in this trial were unvaccinated. Median duration of symptoms and hospitalization prior to first dose of VEKLURY were similar across treatment groups.
The primary endpoint was clinical status on Day 14 assessed on a 7-point ordinal scale consisting of the following categories:
- death;
- hospitalized, receiving invasive mechanical ventilation or ECMO;
- hospitalized, receiving noninvasive ventilation or high-flow oxygen devices;
- hospitalized, requiring low-flow supplemental oxygen;
- hospitalized, not requiring supplemental oxygen but receiving ongoing medical care (related or not related to COVID-19);
- hospitalized, requiring neither supplemental oxygen nor ongoing medical care (other than that specified in the protocol for remdesivir administration); and
- not hospitalized.
Overall, after adjusting for between-group differences at baseline, subjects receiving a 5-day course of VEKLURY had similar clinical status at Day 14 as those receiving a 10-day course (odds ratio for improvement 0.75 [95% CI 0.51 to 1.12]). There were no statistically significant differences in recovery rates or mortality rates in the 5-day and 10-day groups once adjusted for between-group differences at baseline. All-cause mortality at Day 28 was 12% vs 14% in the 5-and 10-day treatment groups, respectively.
Study GS-US-540-5774 In Hospitalized Subjects With Moderate COVID-19
A randomized, open-label multi-center clinical trial (Study 5774) of hospitalized adult subjects with confirmed SARS-CoV-2 infection, SpO2 >94% and radiological evidence of pneumonia compared treatment with VEKLURY for 5 days (n=191) and treatment with VEKLURY for 10 days (n=193) with standard of care (n=200). Treatment with VEKLURY was stopped in subjects who were discharged from the hospital prior to completion of their protocol-defined duration of treatment. Subjects treated with VEKLURY received 200 mg on Day 1 and 100 mg once daily on subsequent days via intravenous infusion.
At baseline, the median age of subjects was 57 years (range, 12 to 95 years); 61% were male, 61% were White, 19% were Black, and 19% were Asian; 18% were Hispanic or Latino. Subjects in this trial were unvaccinated. Baseline clinical status, oxygen support status, and median duration of symptoms and hospitalization prior to first dose of VEKLURY were similar across treatment groups.
The primary endpoint was clinical status on Day 11 assessed on a 7-point ordinal scale consisting of the following categories:
- death;
- hospitalized, receiving invasive mechanical ventilation or ECMO;
- hospitalized, receiving noninvasive ventilation or high-flow oxygen devices;
- hospitalized, requiring low-flow supplemental oxygen;
- hospitalized, not requiring supplemental oxygen but receiving ongoing medical care (related or not related to COVID-19);
- hospitalized, requiring neither supplemental oxygen nor ongoing medical care (other than that specified in the protocol for remdesivir administration); and
- not hospitalized.
Overall, the odds of improvement in the ordinal scale were higher in the 5-day VEKLURY group at Day 11 when compared to those receiving only standard of care (odds ratio 1.65 [95% CI 1.09 to 2.48], p=0.017). The odds of improvement in clinical status with the 10-day treatment group when compared to those receiving only standard of care were not statistically significant (odds ratio 1.31 [95% CI 0.88 to 1.95]). All-cause mortality at Day 28 was ≤2% in all treatment groups.
Study GS-US-540-9012 In Non-Hospitalized Subjects With Mild-To-Moderate COVID-19 And At High Risk For Progression To Severe Disease
A randomized, double-blind, placebo-controlled, clinical trial (Study 9012) evaluated VEKLURY 200 mg once daily for 1 day followed by VEKLURY 100 mg once daily for 2 days (for a total of 3 days of intravenously administered therapy) in 554 adult and 8 pediatric subjects (12 years of age and older and weighing at least 40 kg) who were non-hospitalized, had mild-to-moderate COVID-19, were symptomatic for COVID-19 for ≤7 days, had confirmed SARS-CoV-2 infection, and had at least one risk factor for progression to hospitalization. Risk factors for progression to hospitalization included age ≥60 years, obesity (BMI ≥30), chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes mellitus, immunocompromised state, chronic mild or moderate kidney disease, chronic liver disease, current cancer, and sickle cell disease. Subjects who received, required, or were expected to require supplemental oxygen were excluded from the trial. Subjects were randomized in a 1:1 manner, stratified by residence in a skilled nursing facility (yes/no), age (<60 vs ≥60 years), and region (US vs ex-US) to receive VEKLURY (n=279) or placebo (n=283), plus standard of care.
At baseline, mean age was 50 years (with 30% of subjects aged 60 or older); 52% were male, 80% were White, 8% were Black, and 2% were Asian; 44% were Hispanic or Latino; median body mass index was 30.7 kg/m². Subjects in this trial were unvaccinated. VEKLURY or placebo was first administered to subjects in outpatient facilities (84%), home healthcare settings (13%), or skilled nursing facilities (3%). The most common comorbidities were diabetes mellitus (62%), obesity (56%), and hypertension (48%). Median (Q1, Q3) duration of symptoms prior to treatment was 5 (3, 6) days; median viral load was 6.3 log10 copies/mL at baseline. The baseline demographics and disease characteristics were well balanced across the VEKLURY and placebo treatment groups.
The primary endpoint was the proportion of subjects with COVID-19 related hospitalization (defined as at least 24 hours of acute care) or all-cause mortality through Day 28. Events occurred in 2 (0.7%) subjects treated with VEKLURY compared to 15 (5.3%) subjects concurrently randomized to placebo (hazard ratio 0.134 [95% CI 0.031 to 0.586]; p=0.0076). No deaths were observed through Day 28.
Study GS-US-540-5823 In Hospitalized Pediatric Subjects With COVID-19
The primary objectives of this Phase 2/3 single-arm, open-label clinical trial (Study GS-US-540-5823) were to evaluate pharmacokinetics and safety of up to 10 days of treatment with VEKLURY in pediatric subjects. A total of 58 pediatric subjects from birth (including preterm to term infants) to <18 years of age and weighing at least 1.5 kg with confirmed SARS-CoV-2 infection and mild, moderate, or severe COVID-19 was evaluated in eight cohorts:
- Cohorts 1-4, 8; infants, children, and adolescents: Subjects ≥12 years and weighing ≥40 kg (n=12); subjects <12 years and weighing ≥40 kg (n=5); subjects ≥28 days and weighing ≥20 to <40 kg (n=12); subjects ≥28 days and weighing ≥12 to <20 kg (n=12); and subjects ≥28 days and weighing ≥3 to <12 kg (n=12). Subjects weighing ≥40 kg received 200 mg of VEKLURY on Day 1 followed by VEKLURY 100 mg once daily on subsequent days; subjects weighing ≥3 kg to <40 kg received VEKLURY 5 mg/kg on Day 1 followed by VEKLURY 2.5 mg/kg once daily on subsequent days;
- Cohorts 5-7; neonates and infants: Subjects 14 to <28 days old, GA >37 weeks, and weighing ≥2.5 kg (n=3); subjects <14 days old, GA >37 weeks, and weighing ≥2.5 kg at birth (n=1); and subjects <56 days old, GA ≤37 weeks, and weighing ≥1.5 kg at birth (n=1). Subjects 14 to <28 days old, GA >37 weeks, and weighing ≥2.5 kg received VEKLURY 5 mg/kg on Day 1 followed by VEKLURY 2.5 mg/kg once daily on subsequent days. Subjects <14 days old, GA >37 weeks, and weighing at least 2.5 kg at birth, and subjects <56 days old, GA ≤37 weeks, and weighing ≥1.5 kg at birth, received VEKLURY 2.5 mg/kg on Day 1 followed by VEKLURY 1.25 mg/kg once daily on subsequent days.
Assessments occurred at the following intervals: Screening; Day 1 (Baseline); Days 2-10, or until discharge, whichever came earlier; Follow-Up on Day 30 (±5). Treatment with VEKLURY was stopped in subjects who were discharged from the hospital prior to the completion of 10 days of treatment.
Infants, children, and adolescents: At baseline, median age was 7 years (Q1, Q3: 2 years, 12 years); 57% were female, 70% were White, 30% were Black, and 44% were Hispanic or Latino; median weight was 25 kg (range: 4 to 192 kg). Subjects in this trial were unvaccinated. A total of 12 subjects (23%) were on invasive mechanical ventilation, 18 (34%) were on non-invasive ventilation or high-flow oxygen; 10 (19%) were on low-flow oxygen; and 13 (25%) were on room air, at baseline. The overall median (Q1, Q3) duration of symptoms and hospitalization prior to first dose of VEKLURY was 5 (3, 7) days and 1 (1, 3) day, respectively.
The descriptive outcome analyses showed treatment with VEKLURY for up to 10 days resulted in an overall median (Q1, Q3) change from baseline in clinical status (assessed on a 7-point ordinal scale ranging from death [score of 1] to ventilatory support and decreasing levels of oxygen to hospital discharge [score of 7]) of +2.0 (1.0, 4.0) points on Day 10.
Recovery (defined as an improvement from a baseline clinical status score of 2 through 5 to a score of 6 or 7, or an improvement from a baseline score of 6 to a score of 7) was reported for 62% of subjects on Day 10; median (Q1, Q3) time to recovery was 7 (5, 16) days.
Overall, 60% of subjects were discharged by Day 10, and 83% of subjects were discharged by Day 30. Three subjects (6%) from Cohorts 1-4 and Cohort 8 died during the study.
Neonates and infants: At baseline, subjects ranged in age from 12 to 30 days; 3/5 were female, 4/5 were White, 1/5 was Black; weight ranged from 2.2 to 3.5 kg. Three subjects were on invasive mechanical ventilation and 2 were on high-flow oxygen. The duration of symptoms and hospitalization prior to first dose of VEKLURY ranged from 2 to 9 days and 1 to 9 days, respectively.
The descriptive outcome analyses showed treatment with VEKLURY for up to 10 days resulted in recovery (defined as an improvement from a baseline clinical status score of 2 through 5 to a score of 6 or 7, or an improvement from a baseline score of 6 to a score of 7) for 3 subjects, including for one subject by Day 10. Time to recovery ranged from 9 to 19 days.
Overall, a total of 3 subjects were discharged by Day 30, of which one subject was discharged by Day 10. No subjects from Cohorts 5-7 died during the study.