Drug Interaction Studies
After oral administration of sofosbuvir and velpatasvir, sofosbuvir is rapidly absorbed and subject to extensive first-pass hepatic extraction (hydrolysis followed by sequential phosphorylation) to form the pharmacologically active triphosphate. In clinical pharmacology studies, both sofosbuvir and the primary circulating metabolite GS-331007 (dephosphorylated nucleotide metabolite) were monitored for purposes of pharmacokinetic analyses.
Sofosbuvir and velpatasvir are substrates of drug transporters P-gp and BCRP while GS-331007 is not. Velpatasvir is also transported by OATP1B1 and OATP1B3. In vitro, slow metabolic turnover of velpatasvir by CYP2B6, CYP2C8, and CYP3A4 was observed. Inducers of P-gp and/or moderate to strong inducers of CYP2B6, CYP2C8, or CYP3A4 (e.g., rifampin, St. John's wort, carbamazepine) may decrease plasma concentrations of sofosbuvir and/or velpatasvir, leading to reduced therapeutic effect of sofosbuvir and velpatasvir [see Warnings and Precautions (5.3) and Drug Interactions (7.3)]. Coadministration with drugs that inhibit P-gp and/or BCRP may increase sofosbuvir and/or velpatasvir plasma concentrations without increasing GS-331007 plasma concentration. Drugs that inhibit CYP2B6, CYP2C8, or CYP3A4 may increase plasma concentration of velpatasvir.
Velpatasvir is an inhibitor of drug transporter P-gp, BCRP, OATP1B1, OATP1B3, and OATP2B1, and its involvement in drug interactions with these transporters is primarily limited to the process of absorption. At clinically relevant concentration, velpatasvir is not an inhibitor of hepatic transporters OATP1A2 or OCT1, renal transporters OCT2, OAT1, OAT3, or MATE1, or CYP or UGT1A1 enzymes.
Sofosbuvir and GS-331007 are not inhibitors of drug transporters P-gp, BCRP, OATP1B1, OATP1B3, and OCT1 and GS-331007 is not an inhibitor of OAT1, OAT3, OCT2, and MATE1. Sofosbuvir and GS-331007 are not inhibitors or inducers of CYP or UGT1A1 enzymes.
The effects of coadministered drugs on the exposure of sofosbuvir, GS-331007, and velpatasvir are shown in Table 8. The effects of sofosbuvir, velpatasvir, or sofosbuvir and velpatasvir on the exposure of coadministered drugs are shown in Table 9 [see Drug Interactions (7)].
Table 8 Drug Interactions: Changes in Pharmacokinetic Parameters for Sofosbuvir, GS-331007, and Velpatasvir in the Presence of the Coadministered Drug
| Coadministered Drug | Dose of Coadministered Drug (mg) | SOF Dose (mg) | VEL Dose (mg) | N | Mean Ratio (90% CI) of Sofosbuvir, GS-331007, and Velpatasvir PK With/Without Coadministered Drug No Effect=1.00 |
|---|
| Cmax
| AUC | Cmin
|
|---|
| NA = not available/not applicable, ND = not dosed, DF = disoproxil fumarate. |
| Atazanavir/ ritonavir + emtricitabine/ tenofovir DF | 300/100 + 200/300 once daily | 400 once daily | 100 once daily | 24 | sofosbuvir | 1.12 (0.97, 1.29) | 1.22 (1.12, 1.33) | NA |
| GS-331007 | 1.21 (1.12, 1.29) | 1.32 (1.27, 1.36) | 1.42 (1.37, 1.49) |
| velpatasvir | 1.55 (1.41, 1.71) | 2.42 (2.23, 2.64) | 4.01 (3.57, 4.50) |
| Carbamazepine | 300 twice daily | 400 single dose | ND | 24 | sofosbuvir | 0.52 (0.43, 0.62) | 0.52 (0.46, 0.59) | NA |
| GS-331007 | 1.04 (0.97, 1.11) | 0.99 (0.94, 1.04) | NA |
| Cyclosporine | 600 single dose | 400 single dose | ND | 19 | sofosbuvir | 2.54 (1.87, 3.45) | 4.53 (3.26, 6.30) | NA |
| GS-331007 | 0.60 (0.53, 0.69) | 1.04 (0.90, 1.20) | NA |
| ND | 100 single dose | 12 | velpatasvir | 1.56 (1.22, 2.01) | 2.03 (1.51, 2.71) | NA |
| Darunavir/ ritonavir + emtricitabine/ tenofovir DF | 800/100 + 200/300 once daily | 400 once daily | 100 once daily | 29 | sofosbuvir | 0.62 (0.54, 0.71) | 0.72 (0.66, 0.80) | NA |
| GS-331007 | 1.04 (0.99, 1.08) | 1.13 (1.08, 1.18) | 1.13 (1.06, 1.19) |
| velpatasvir | 0.76 (0.65, 0.89) | 0.84 (0.72, 0.98) | 1.01 (0.87, 1.18) |
| Efavirenz/ emtricitabine/ tenofovir DF
| 600/200/300 once daily | 400 once daily | 100 once daily | 14 | sofosbuvir | 1.38 (1.14, 1.67) | 0.97 (0.83, 1.14) | NA |
| GS-331007 | 0.86 (0.80, 0.93) | 0.90 (0.85, 0.96) | 1.01 (0.95, 1.07) |
| velpatasvir | 0.53 (0.43, 0.64) | 0.47 (0.39, 0.57) | 0.43 (0.36, 0.52) |
Elvitegravir/ cobicistat/ emtricitabine/ tenofovir alafenamide
| 150/150/200/10 once daily | 400 once daily | 100 once daily | 24 | sofosbuvir | 1.23 (1.07, 1.42) | 1.37 (1.24, 1.52) | NA |
| GS-331007 | 1.29 (1.25, 1.33) | 1.48 (1.43, 1.53) | 1.58 (1.52, 1.65) |
| velpatasvir | 1.30 (1.17, 1.45) | 1.50 (1.35, 1.66) | 1.60 (1.44, 1.78) |
Elvitegravir/ cobicistat/ emtricitabine/ tenofovir DF
| 150/150/200/300 once daily | 400 once daily | 100 once daily | 24 | sofosbuvir | 1.01 (0.85, 1.19) | 1.24 (1.13, 1.37) | NA |
| GS-331007 | 1.13 (1.07, 1.18) | 1.35 (1.30, 1.40) | 1.45 (1.38, 1.52) |
| velpatasvir | 1.05 (0.93, 1.19) | 1.19 (1.07, 1.34) | 1.37 (1.22, 1.54) |
| Famotidine | 40 single dose simultaneously with sofosbuvir and velpatasvir tablets | 400 single dose | 100 single dose | 60 | sofosbuvir | 0.92 (0.82, 1.05) | 0.82 (0.74, 0.91) | NA |
| GS-331007 | 0.84 (0.78, 0.89) | 0.94 (0.91, 0.98) | NA |
| velpatasvir | 0.80 (0.70, 0.91) | 0.81 (0.71, 0.91) | NA |
| 40 single dose 12 hours prior to sofosbuvir and velpatasvir tablets | 60 | sofosbuvir | 0.77 (0.68, 0.87) | 0.80 (0.73, 0.88) | NA |
| GS-331007 | 1.20 (1.13, 1.28) | 1.04 (1.01, 1.08) | NA |
| velpatasvir | 0.87 (0.76, 1.00) | 0.85 (0.74, 0.97) | NA |
| Ketoconazole | 200 twice daily | ND | 100 single dose | 12 | velpatasvir | 1.29 (1.02, 1.64) | 1.71 (1.35, 2.18) | NA |
| Lopinavir/ ritonavir + emtricitabine/ tenofovir DF | 4x200/50 + 200/300 once daily | 400 once daily | 100 once daily | 24 | sofosbuvir | 0.59 (0.49, 0.71) | 0.71 (0.64, 0.78) | NA |
| GS-331007 | 1.01 (0.98, 1.05) | 1.15 (1.09, 1.21) | 1.15 (1.07, 1.25) |
| velpatasvir | 0.70 (0.59, 0.83) | 1.02 (0.89, 1.17) | 1.63 (1.43, 1.85) |
| Methadone | 30 to 130 daily | 400 once daily | ND | 14 | sofosbuvir | 0.95 (0.68, 1.33) | 1.30 (1.00, 1.69) | NA |
| GS-331007 | 0.73 (0.65, 0.83) | 1.04 (0.89, 1.22) | NA |
| Omeprazole | 20 once daily simultaneously with sofosbuvir and velpatasvir tablets
| 400 single dose fasted | 100 single dose fasted | 60 | sofosbuvir | 0.66 (0.55, 0.78) | 0.71 (0.60, 0.83) | NA |
| GS-331007 | 1.18 (1.10, 1.26) | 1.00 (0.95, 1.05) | NA |
| velpatasvir | 0.63 (0.50, 0.78) | 0.64 (0.52, 0.79) | NA |
| 20 once daily 12 hours prior to sofosbuvir and velpatasvir tablets | 400 single dose fasted | 100 single dose fasted | 60 | sofosbuvir | 0.55 (0.47, 0.64) | 0.56 (0.49, 0.65) | NA |
| GS-331007 | 1.26 (1.18, 1.34) | 0.97 (0.94, 1.01) | NA |
| velpatasvir | 0.43 (0.35, 0.54) | 0.45 (0.37, 0.55) | NA |
| 20 once daily 2 hours prior to sofosbuvir and velpatasvir tablets | 400 single dose fed
| 100 single dose fed
| 40 | sofosbuvir | 0.84 (0.68, 1.03) | 1.08 (0.94, 1.25) | NA |
| GS-331007 | 0.94 (0.88, 1.02) | 0.99 (0.96, 1.03) | NA |
| velpatasvir | 0.52 (0.43, 0.64) | 0.62 (0.51, 0.75) | NA |
| 20 once daily 4 hours after sofosbuvir and velpatasvir tablets | 400 single dose fed
| 100 single dose fed
| 38 | sofosbuvir | 0.79 (0.68, 0.92) | 1.05 (0.94, 1.16) | NA |
| GS-331007 | 0.91 (0.85, 0.98) | 0.99 (0.95, 1.02) | NA |
| velpatasvir | 0.67 (0.58, 0.78) | 0.74 (0.63, 0.86) | NA |
| 40 once daily 4 hours after sofosbuvir and velpatasvir tablets | 400 single dose fed
| 100 single dose fed
| 40 | sofosbuvir | 0.70 (0.57, 0.87) | 0.91 (0.76, 1.08) | NA |
| GS-331007 | 1.01 (0.96, 1.07) | 0.99 (0.94, 1.03) | NA |
| velpatasvir | 0.44 (0.34, 0.57) | 0.47 (0.37, 0.60) | NA |
| Rifabutin | 300 once daily | 400 single dose | ND | 20 | sofosbuvir | 0.64 (0.53, 0.77) | 0.76 (0.63, 0.91) | NA |
| GS-331007 | 1.15 (1.03, 1.27) | 1.03 (0.95, 1.12) | NA |
| Rifampin | 600 once daily | 400 single dose | ND | 17 | sofosbuvir | 0.23 (0.19, 0.29) | 0.28 (0.24, 0.32) | NA |
| GS-331007 | 1.23 (1.14, 1.34) | 0.95 (0.88, 1.03) | NA |
| ND | 100 single dose | 12 | velpatasvir | 0.29 (0.23, 0.37) | 0.18 (0.15, 0.22) | NA |
| 600 single dose | ND | 100 single dose | 12 | velpatasvir | 1.28 (1.05, 1.56) | 1.46 (1.17, 1.83) | NA |
| Tacrolimus | 5 single dose | 400 single dose | ND | 16 | sofosbuvir | 0.97 (0.65, 1.43) | 1.13 (0.81, 1.57) | NA |
| GS-331007 | 0.97 (0.83, 1.14) | 1.00 (0.87, 1.13) | NA |
No effect on the pharmacokinetic parameters of sofosbuvir, GS-331007, or velpatasvir was observed with dolutegravir; the combination of emtricitabine, rilpivirine, and tenofovir DF; emtricitabine; raltegravir; or tenofovir DF.
Table 9 Changes in Pharmacokinetic Parameters for Coadministered Drug in the Presence of Sofosbuvir, Velpatasvir, or Sofosbuvir and Velpatasvir
| Coadministered Drug | Dose of Coadministered Drug (mg) | SOF Dose (mg) | VEL Dose (mg) | N | Mean Ratio (90% CI) of Coadministered Drug PK With/Without Sofosbuvir, Velpatasvir, or Sofosbuvir and Velpatasvir No Effect=1.00 |
|---|
| Cmax
| AUC | Cmin
|
|---|
| NA = not available/not applicable, ND = not dosed, DF = disoproxil fumarate. |
| Atazanavir/ ritonavir + emtricitabine/ tenofovir DF
| atazanavir 300 once daily | 400 once daily | 100 once daily | 24 | 1.09 (1.00, 1.19) | 1.20 (1.10, 1.31) | 1.39 (1.20, 1.61) |
| ritonavir 100 once daily | 0.89 (0.82, 0.97) | 0.97 (0.89, 1.05) | 1.29 (1.15, 1.44) |
| emtricitabine 200 once daily | 1.01 (0.96, 1.06) | 1.02 (0.99, 1.04) | 1.06 (1.02, 1.11) |
| tenofovir DF 300 once daily | 1.55 (1.43, 1.68) | 1.30 (1.24, 1.36) | 1.39 (1.31, 1.48) |
| Atorvastatin | 40 single dose | 400 once daily | 100 once daily | 26 | 1.68 (1.49, 1.89) | 1.54 (1.45, 1.64) | NA |
| Darunavir/ ritonavir + emtricitabine/ tenofovir DF
| darunavir 800 once daily | 400 once daily | 100 once daily | 29 | 0.90 (0.86, 0.95) | 0.92 (0.87, 0.98) | 0.87 (0.79, 0.95) |
| ritonavir 100 once daily | 1.07 (0.97, 1.17) | 1.12 (1.05, 1.19) | 1.09 (1.02, 1.15) |
| emtricitabine 200 once daily | 1.05 (1.01, 1.08) | 1.05 (1.02, 1.08) | 1.04 (0.98, 1.09) |
| tenofovir DF 300 once daily | 1.55 (1.45, 1.66) | 1.39 (1.33, 1.44) | 1.52 (1.45, 1.59) |
| Digoxin | 0.25 single dose | ND | 100 | 21 | 1.88 (1.71, 2.08) | 1.34 (1.13, 1.60) | NA |
| Efavirenz/ emtricitabine/ tenofovir DF
| efavirenz 600 once daily | 400 once daily | 100 once daily | 15 | 0.81 (0.74, 0.89) | 0.85 (0.80, 0.91) | 0.90 (0.85, 0.95) |
| emtricitabine 200 once daily | 1.07 (0.98, 1.18) | 1.07 (1.00, 1.14) | 1.10 (0.97, 1.25) |
| tenofovir DF 300 once daily | 1.77 (1.53, 2.04) | 1.81 (1.68, 1.94) | 2.21 (2.00, 2.43) |
Elvitegravir/ cobicistat/ emtricitabine/ tenofovir alafenamide
| elvitegravir 150 once daily | 400 once daily | 100 once daily | 24 | 0.87 (0.80, 0.94) | 0.94 (0.88, 1.00) | 1.08 (0.97, 1.20) |
| cobicistat 150 once daily | 1.16 (1.09, 1.23) | 1.30 (1.23, 1.38) | 2.03 (1.67, 2.48) |
| emtricitabine 200 once daily | 1.02 (0.97, 1.06) | 1.01 (0.98, 1.04) | 1.02 (0.97, 1.07) |
| tenofovir alafenamide 10 once daily | 0.80 (0.68, 0.94) | 0.87 (0.81, 0.94) | NA |
Elvitegravir/ cobicistat/ emtricitabine/ tenofovir DF
| elvitegravir 150 once daily | 400 once daily | 100 once daily | 24 | 0.93 (0.86, 1.00) | 0.93 (0.87, 0.99) | 0.97 (0.91, 1.04) |
| cobicistat 150 once daily | 1.11 (1.06, 1.17) | 1.23 (1.17, 1.29) | 1.71 (1.54, 1.90) |
| emtricitabine 200 once daily | 1.02 (0.97, 1.08) | 1.01 (0.98, 1.04) | 1.06 (1.01, 1.11) |
| tenofovir DF 300 once daily | 1.36 (1.25, 1.47) | 1.35 (1.29, 1.42) | 1.45 (1.39, 1.51) |
| Emtricitabine/ rilpivirine/ tenofovir DF
| emtricitabine 200 once daily | 400 once daily | 100 once daily | 24 | 0.95 (0.90, 1.00) | 0.99 (0.97, 1.02) | 1.05 (0.99, 1.11) |
| rilpivirine 25 once daily | 0.93 (0.88, 0.98) | 0.95 (0.90, 1.00) | 0.96 (0.90, 1.03) |
| tenofovir DF 300 once daily | 1.44 (1.33, 1.55) | 1.40 (1.34, 1.46) | 1.84 (1.76, 1.92) |
| Norelgestromin | norgestimate 0.180/0.215/0.25/ethinyl estradiol 0.025 once daily | ND | 100 once daily | 13 | 0.97 (0.88, 1.07) | 0.90 (0.82, 0.98) | 0.92 (0.83, 1.03) |
| 400 once daily | ND | 15 | 1.07 (0.94, 1.22) | 1.06 (0.92, 1.21) | 1.07 (0.89, 1.28) |
| Norgestrel | ND | 100 once daily | 13 | 0.96 (0.78, 1.19) | 0.91 (0.73, 1.15) | 0.92 (0.73, 1.18) |
| 400 once daily | ND | 15 | 1.18 (0.99, 1.41) | 1.19 (0.98, 1.45) | 1.23 (1.00, 1.51) |
| Ethinyl estradiol | ND | 100 once daily | 12 | 1.39 (1.17, 1.66) | 1.04 (0.87, 1.24) | 0.83 (0.65, 1.06) |
| 400 once daily | ND | 15 | 1.15 (0.97, 1.36) | 1.09 (0.94, 1.26) | 0.99 (0.80, 1.23) |
| Pravastatin | 40 single dose | ND | 100 once daily | 18 | 1.28 (1.08, 1.52) | 1.35 (1.18, 1.54) | NA |
| Rosuvastatin | 10 single dose | ND | 100 once daily | 18 | 2.61 (2.32, 2.92) | 2.69 (2.46, 2.94) | NA |
| Raltegravir + emtricitabine/ tenofovir DF | emtricitabine 200 once daily | 400 once daily | 100 once daily | 30 | 1.08 (1.04, 1.12) | 1.05 (1.03, 1.07) | 1.02 (0.97, 1.08) |
| tenofovir DF 300 once daily | 1.46 (1.39, 1.54) | 1.40 (1.34, 1.45) | 1.70 (1.61, 1.79) |
| raltegravir 400 twice daily | 1.03 (0.74, 1.43) | 0.97 (0.73, 1.28) | 0.79 (0.42, 1.48) |
| Tacrolimus | 5 single dose | 400 single dose | ND | 16 | 0.73 (0.59, 0.90) | 1.09 (0.84, 1.40) | NA |
No effect on the pharmacokinetic parameters of the following coadministered drugs was observed or is expected with sofosbuvir and velpatasvir (buprenorphine/naloxone, dolutegravir, lopinavir/ritonavir, or methadone) or its components sofosbuvir (cyclosporine) or velpatasvir (cyclosporine).