An open label, prospective, randomized, controlled, two-arm cross-over Phase 2 study with Wilate and a comparator product was conducted at 6 sites in the US. In this study, pharmacokinetic (PK) profiles of Wilate were determined by FVIII activity, VWF:RCo, VWF:Ag, and VWF:CB.
Each of twenty-two subjects with inherited VWD [Type 1, n=6; Type 2, n=9 (6 Type 2A, 1 Type 2B, and 2 Type 2M); and Type 3, n=7] received an intravenous bolus dose of Wilate containing approximately 40 IU of VWF:RCo/kg BW. Twenty subjects completed the study as per protocol. PK parameters of VWF:RCo and FVIII are summarized in
Table 3
and
Table 4
, respectively.
Table 3 Pharmacokinetic Parameters of VWF:RCo:mean ± SD (range)
|
Parameters |
VWD type I (n = 5) |
VWD type II (n = 9) |
VWD type III (n = 6) |
Total (n = 20) |
|---|
Cmax (IU/dL) |
74 ± 13
(62 - 91) |
77 ± 18
(40 - 100) |
79 ± 13
(65 - 102) |
76 ± 15
(40 - 102) |
AUC(0-inf)
(IU*hr/dL) |
1633 ± 979
(984 - 3363) |
1172 ± 421
(571 - 1897) |
995 ± 292
(527 - 1306) |
1235 ± 637
(527 - 3363) |
Half-life (hrs) |
24.7 ± 17.9
(11.2 - 48.5 ) |
15.3 ± 6.3
(6.0 - 26.4) |
9.1± 2.6
(5.7 - 12.9 ) |
15.8 ± 11.0
(5.7 - 48.5) |
CL (mL/h/kg) |
3.1 ± 1.1
(1.2 - 4.1) |
4.1 ± 1.7
(2.0 - 7.1) |
4.2 ± 1.4
(3.0 - 6.6) |
3.9 ± 1.5
(1.2 - 7.1) |
Vss (mL/kg) |
81.7 ± 38.5
(15.3 - 74.2) |
76.6 ± 35.4
(45.3 - 158.8) |
49.4 ± 16.7
(29.7 - 67.1) |
69.7 ± 33.2
(29.7 - 158.8) |
MRT (hrs) |
32.7 ± 25.8
(15.3 - 74.2) |
19.7 ± 5.6
(9.9 - 27.1) |
11.9 ± 2.9
(9.2 - 15.9) |
20.6 ± 14.8
(9.2 - 74.2) |
Recovery
(%IU/kg) |
1.8 ± 0.2
(1.5 - 2.0) |
1.8 ± 0.5
(1.0 - 2.4) |
2.1 ± 0.3
(1.8 - 2.6) |
1.9 ± 0.4
(1.0 - 2.6) |
C
max
= peak concentration; AUC = area under curve; CL = clearance; Vss = volume of distribution at steady state; MRT = mean residence time
The PK parameters reported in
Table 3
are based on VWF:RCo values obtained using a modified Behring Coagulation System (BCS) analytical method. The modified BCS was used because of its validated lower variability compared to the standard BCS. The measured concentrations (IU VWF:RCo/mL) are higher by the modified BCS than by the standard BCS analytical method which is used in some clinical laboratories. Dose adjusted C
max
and AUC determined by this modified BCS method are approximately 1.5 times higher than those by the standard BCS method. No difference has been found in incremental recovery.
Table 4 Pharmacokinetic Parameters of FVIII:C: mean ± SD (range) - chromogenic
|
Parameters |
VWD type I (n = 5) |
VWD type II (n = 8*) |
VWD type III (n = 6) |
Total (n = 19*) |
|---|
Cmax (IU/dL) |
117.1 ± 12.1
(103 - 135) |
147.2 ± 32.6
(102 - 206) |
120 ± 23
(91 - 148) |
112 ± 23
(59 - 148) |
AUC(0-inf)
(IU*hr/dL) |
1187 ± 382
(523 - 1483) |
1778 ± 1430
(544 - 4821) |
2670 ± 854
(1874 - 3655) |
2290 ± 1045
(464 - 4424) |
Half-life (hrs) |
17.5 ± 4.9
(10.9 - 23.8) |
23.6 ± 8.3
(12.6 - 34.7) |
16.1 ± 3.1
(11.8 - 20.1) |
19.6 ± 6.9
(10.9 - 34.7) |
CL (mL/h/kg) |
4.4 ± 3.7
(2.5 - 11.0) |
2.5 ± 0.9
(1.2 - 3.5) |
2.0 ± 0.6
(1.4 - 2.8) |
2.9 ± 2.1
(1.2 - 11.0) |
Vss (mL/kg) |
95.0 ± 53.8
(57.1 - 190.0) |
79.5 ± 23.1
(52.8 - 116.2) |
44.2 ± 10.4
(31.8 - 57.1) |
72.4 ± 36.2
(31.8 - 190.0) |
MRT (hrs) |
24.1 ± 5.5(17.2 - 31.5) |
35.1 ± 14.2
(17.5 - 61.6) |
23.0 ± 3.7
(18.0 - 27.7) |
28.4 ± 11.1
(17.2 - 61.6) |
Recovery
(%IU/kg) |
1.9 ± 0.5
(1.1 - 2.5) |
2.2 ± 0.4
(1.6 - 2.8) |
2.5 ± 0.5
(2.0 - 3.0) |
2.2 ± 0.5
(1.1 - 3.0) |
C
max
= peak concentration; AUC = area under curve; CL = clearance; Vss = volume of distribution at steady state; MRT = mean residence time
Effect of age and VWD type on the pharmacokinetics of Wilate:
Due to small sample size (in age or VWD type subsets) and high PK variability, it is difficult to conclude if age or type of VWD had any impact on the pharmacokinetics of Wilate.
Effect of gender on the pharmacokinetics of Wilate:
Based on PK data of Wilate from 8 males and 12 females, it appears that the females (4.35 ± 1.54 mL/hr/kg) had higher clearance of VWF:RCo than the males (3.16 ± 1.19 mL/hr/kg). The clinical significance of this finding is not known.