CLINICAL PHARMACOLOGY
Mechanism Of Action
In VWD patients, VONVENDI acts 1) to promote hemostasis by mediating platelet adhesion
to damaged vascular sub-endothelial matrix (e.g. collagen) and platelet aggregation, and 2)
as a carrier protein for factor VIII, protecting it from rapid proteolysis. The adhesive activity of
VWF depends on the size of its multimers, with larger multimers being the most effective in
supporting interactions with collagen and platelet receptors.1 The binding capacity and affinity
of VONVENDI to factor VIII in plasma is comparable to that of endogenous VWF, allowing for
VONVENDI to reduce factor VIII clearance.2
Pharmacodynamics
There have been no specific pharmacodynamics studies on rVWF.
Pharmacokinetics
The PK profile of VONVENDI was determined in 2 clinical trials by assessment of VWF:RCo,
VWF:Ag, and VWF:CB. Subjects were evaluated in the non-bleeding state. Sustained increase
of FVIII:C was observed by 6 hours after a single infusion of VONVENDI.
Table 7 below summarizes the PK parameters of VONVENDI after infusions of 50 IU/kg (PK50)
or 80 IU/kg VWF:RCo (PK80) VONVENDI.
Table 7. Pharmacokinetic Assessment of VWF:RCo
Parameter [unit] |
Phase 1 PK50 VONVENDI with ADVATEa Mean (SD) Min;Max |
Phase 3 PK50 VONVENDI Mean (SD) Min;Max |
Phase 3 PK80 VONVENDI Mean (SD) Min;Max |
T1/2 [hours] |
19.3 (10.99)10.8;51.2 |
22.6 (5.34) 17.0;37.2 |
19.1 (4.32 11.8;28.0 |
CI [dL/kg/hour] |
0.04 (0.028) 0.01;0.16 |
0.02 (0.005) 0.02;0.04 |
0.03 (0.009) 0.02;0.05 |
IR [(U/dL)/(U VWF:RCo/kg)] |
1.7 (0.62) 1.0;3.6 |
1.9 (0.41) 1.2;2.7 |
2.0 (0.39) 1.4;2.9 |
AUC0-in [(h*U/dL)] |
1541.4 (554.31) 173.8;2862.0 |
2105.4 (427.51)1334.0;2813.3 |
2939.0 (732.72) 1507.8;4121.1 |
AUC0-inf/Dose [(h*U/dL)/(U VWF:RCo/kg)] |
33.4 (13.87) 6.4;70.4 |
42.1 (8.31) 27.8;54.8 |
36.8 (8.97) 18.8;50.4 |
aThis trial was done using ADVATE [Antihemophilic factor (recombinant)], a recombinant factor VIII. |
Clinical Studies
On-Demand Treatment And Control Of Bleeding Episodes
Hemostatic efficacy of VONVENDI was assessed in a multicenter, open label trial investigating
different dosing strategies with and without recombinant factor VIII for on demand treatment
and control of bleeding episodes in adults (age 18 years and older) diagnosed with von
Willebrand disease. In this trial, all subjects requiring recombinant factor VIII received ADVATE
[Antihemophilic factor (recombinant)].
Bleeding episodes were treated initially with an infusion of VONVENDI and ADVATE at a ratio
of 1.3:1 respectively (i.e., 30% more VONVENDI than ADVATE), and subsequently with
VONVENDI with or without ADVATE, based on FVIII:C levels. The aim of the initial dose of
VONVENDI with ADVATE was to achieve target plasma levels of greater than 60 IU/dL (60%)
VWF:RCo and greater than 40 IU/dL (40%) of FVIII:C.
A total of 193 bleeding episodes were reported in 22/37 subjects exposed to VONVENDI.
Demographic and baseline characteristics are listed in Table 8.
Table 8. Demographic and Baseline Characteristics
Parameter |
Category |
Exposed subjects n = 37 n (%) |
Treated Subjects n = 22 n (%) |
Gender |
Male |
17 (45.9) |
10 (45.5) |
Female |
20 (54.1) |
12 (54.5) |
Age |
median (years) |
37.0 |
28.0 |
Race |
Caucasian |
32 (86.5) |
20 (90.9) |
Asian |
5 (13.5) |
2 (9.1) |
Ethnicity |
Hispanic or Latino |
2 (5.4) |
2 (9.1) |
Not Hispanic or Latino |
35 (94.6) |
20 (90.9) |
VWD type |
1 |
2 (5.4) |
0 (0.0) |
2A |
5 (13.5) |
4 (18.2) |
2B |
0 (0.0) |
0 (0.0) |
2M |
0 (0.0) |
0 (0.0) |
2N |
1 (2.7) |
1 (4.5) |
3 |
29 (78.4) |
17 (77.3) |
The primary efficacy endpoint was the number of subjects with treatment success for control
of bleeding episodes. Treatment success was defined as a mean efficacy rating score of less
than 2.5 for all bleeding episodes in a subject treated with VONVENDI (with or without ADVATE)
during the trial period. The efficacy rating was assessed using a pre-specified 4-point rating
scale comparing the prospectively estimated number of infusions needed to treat the bleeding
episodes as assessed by the investigator to the actual number of infusions administered.
The definitions for each of the 4-point rating scales are provided in Table 9.
Table 9. Definitions of 4 Point Rating Scales
Rating |
Minor and Moderate Bleeding Events |
Major Bleeding Events |
Excellent (= 1) |
Actual number of infusions ≤ estimated number of infusions required to treat that bleeding episode.
No additional VWF coagulation factor containing product required. |
Actual number of infusions ≤ estimated number of infusions required to treat that bleeding episode.
No additional VWF coagulation factor containing product required. |
Good (= 2) |
1-2 infusions greater than estimated required to control that bleeding episode. No additional VWF coagulation factor containing product required. |
<1.5x infusions greater than estimated required to control that bleeding episode. No additional VWF coagulation factor containing product required. |
Moderate (= 3) |
3 or more infusions greater than estimated used to control that bleeding event. No additional VWF coagulation factor containing product required. |
≥1.5x more infusions greater than estimated used to control that bleeding event.No additional VWF coagulation
factor containing product required. |
None (= 4) |
Severe uncontrolled bleeding or intensity of bleeding not changed. Additional VWF coagulation factor containing product required. |
Severe uncontrolled bleeding or intensity of bleeding not changed. Additional VWF coagulation factor containing product required. |
Secondary efficacy measures were the number of treated bleeding episodes with an efficacy
rating of 'excellent' or 'good,' the number of infusions and number of units of VONVENDI,
administered with or without ADVATE, per bleeding episode.
The primary efficacy assessment excluded subjects with GI bleeds (n=2), and subjects in
whom the number of infusions to control a bleeding episode was estimated retrospectively
(n=2). The rate of subjects (n=18) with treatment success was 100% (95% CI 81.5 to 100).
Sensitivity analyses of treatment success for bleeding episodes including GI bleeds and those
bleeding episodes for which the investigator had to make retrospective assessment of the
number of infusions required (n=22: 17 with type 3 VWD, 4 with type 2A VWD and 1 with
type 2N VWD) confirmed the primary analysis, with a 100% treatment success rate for each
scenario.
All bleeding episodes treated with VONVENDI and ADVATE or VONVENDI alone were controlled
with an efficacy rating of excellent (96.9%) or good (3.1%). Control of bleeding episodes
was consistent across all degrees of severity.
For an overview of hemostatic efficacy by bleeding severity and number of infusions required
to treat a bleeding episode refer to Table 10.
Table 10. Number of Infusions by Severity of Bleeding Episodesa
Number of Infusions per Bleed |
Severity of Bleeding Episodesa |
Minor n (%) n=122 |
Moderate n (%) n=61 |
Major/Severe n (%) n=7 |
Unknown n (%) n=2 |
All n (%) n=192 |
1 |
113 (92.6%) |
41 (67.2%) |
1 (14.3%) |
2 (100%) |
157 (81.8%) |
2 |
8 (6.6%) |
13 (21.3%) |
4 (57.1%) |
0 (0.0) |
25 (13.0%) |
3 |
1 (0.8%) |
6 (9.8%) |
2 (28.6%) |
0 (0.0) |
9 (4.7%) |
4 |
0 (0.0) |
1 (1.6%) |
0 (0.0) |
0 (0.0) |
1 (0.5%) |
Median |
1 |
1 |
2 |
1 |
1 |
Range |
1-3 |
1-4 |
1-3 |
1-4 |
1-4 |
a One subject received plasma-derived VWF for one bleeding episode for the 3rd infusion and therefore was excluded from Table 10. |
The median cumulative dose of VONVENDI administered per bleeding episode (with or without
ADVATE) was 48.2 IU/kg (90% CI, 43.9 to 50.2) IU/kg. In relation to bleeding severity, the
median cumulative dose to treat a bleeding episode was 43.3 (range, 25.2 to 158.2) IU/kg
for minor bleeding episodes (n=122), 52.7 (range, 23.8 to 184.9) IU/kg for moderate bleeding
episodes (n=61), 100 (range, 57.5 to 135) IU/kg for major bleeding episodes (n=7).
Table 11 summarizes data obtained for number of infusions and efficacy rating per bleeding
episode by location.
Table 11. Efficacy by Bleeding Episode Location
Bleeding Episodes by Location (n) |
Median Number of Infusions (Range) |
Rating (%) |
Joint (n=59) |
1 (1 to 3) |
Excellent (96.6%) |
Good (3.4%) |
GI (n=6) |
1 (1 to 2) |
Excellent (83.3%) |
Good (16.7%) |
Mucosal: Genital Tract Female (n=32) |
1 (1 to 2) |
Excellent (96.9%) |
Good (3.1%) |
Mucosal: Nasopharyngeal (n=42) |
1 (1 to 2) |
Excellent (97.6%) |
Good (2.4%) |
Mucosal: Mouth and Oral Cavity (n=26) |
1 (1 to 4) |
Excellent (100%) |
Good (0%) |
Perioperative Management Of Bleeding
Hemostatic efficacy of VONVENDI was assessed in a prospective, open-label, multicenter
trial to evaluate efficacy and safety of VONVENDI with or without ADVATE in elective surgical
procedures in adults (age 18 years and older) diagnosed with severe VWD and the subjects
were followed for 14 days after surgery.
A total of 15 VWD subjects completed the trial and 93% of the subjects were less than
65 years old (range 20 to 70 years), of whom 53.3% were females and 53% (8/15) were
Type 3 VWD patients. Out of 15 subjects, 10 subjects underwent major surgeries and
5 subjects underwent minor surgeries.
Major surgeries included orthopedic surgeries: total hip replacement, total knee replacement,
knee endoprosthesis, ankle prosthesis, anterior cruciate ligament surgery and meniscectomy.
Other major surgeries included laparoscopic cholecystectomy, laparoscopic cystectomy and
complex dental extractions. Minor surgeries/procedures included nasopharyngoscopy, dental
extractions, colonoscopy and radioisotope synovectomy.
All subjects were administered a 12 to 24 hour preoperative dose of 40 to 60 IU/kg of
VONVENDI to increase the factor VIII levels to target levels. Within 3 hours prior to surgery,
the subjects’ FVIII:C levels were assessed to ensure that target of 30 IU/dL for minor surgeries
and 60 IU/dL for major surgeries was achieved. Within 1 hour prior to surgery, subjects
received a dose of VONVENDI. ADVATE (recombinant Factor VIII) was administered based on
FVIII:C levels performed 3 hours prior to surgery. VWF and factor VIII Incremental recovery
were used to guide the initial and subsequent doses.
Six of the 10 subjects undergoing major surgery received protocol-specified loading dose. It
should be noted that the protocol-specified loading dose was based on VWF:RCo levels
assessed prior to the 12 to 24 hour preoperative dose. Four of 10 subjects undergoing major
surgery and 4 out of 5 subjects undergoing minor surgery received a loading dose of
VONVENDI based on VWF:RCo assessed prior to loading dose and after administration of the
12 to 24 hour preoperative dose. Unlike the protocol-specified loading dose based on the
levels assessed prior to the preoperative dose between 12 to 24 hours of the surgery, the
loading doses in these eight subjects were calculated based on VWF:RCo levels after a
preoperative dose, and were therefore lower doses than protocol-specified loading dose. No
differences in safety or efficacy were noted between the two groups.
The primary outcome measure was the overall hemostatic efficacy assessed 24 hours after
the last perioperative VONVENDI infusion or at completion of study visit whichever occurred
earlier using a 4-point ordinal efficacy scale outlined in Table 12 (“excellent”, “good”,
“moderate” and “none”) based on estimated expected versus actual blood loss, transfusion
requirements and postoperative bleeding and oozing. A rating of excellent or good was
required to declare the outcome a success.
Table 12. Primary Efficacy Assessment
Rating |
Overall Assessment of Hemostatic Efficacy 24 hours after last Rating Perioperative IP Infusion or at Day 14 Completion Visit
(Whatever Occurs Earlier) |
Excellent (1) |
Intra-, and postoperative hemostasis achieved with rVWF with or
without ADVATE was as good or better than that expected for the type
of surgical procedure performed in a hemostatically normal subject |
Good (2) |
Intra-, and postoperative hemostasis achieved with rVWF with or
without ADVATE was probably as good as that expected for the type of
surgical procedure performed in a hemostatically normal subject |
Moderate (3) |
Intra-, and postoperative hemostasis with rVWF with or without ADVATE
was clearly less than optimal for the type of procedure performed but
was maintained without the need to change the rVWF concentrate |
None (4) |
Subject experienced uncontrolled bleeding that was the result of
inadequate therapeutic response despite proper dosing, necessitating
a change of rVWF concentrate |
Overall hemostatic efficacy for major and minor surgeries was 100% (15/15) with a 90%
confidence interval of 81.9% to 100%. It was excellent for 60% of surgeries and good for
40% of surgeries.
Intraoperative hemostatic efficacy was a secondary endpoint. For major and minor surgeries,
it was 100% with a 90% confidence interval of 81.9% to 100%. It was excellent for 73.3%
of surgeries and good for 26.7% of surgeries.
For details regarding hemostatic efficacy for minor and major surgery, see Table 13.
Table 13. Overall Hemostatic Efficacy
Type of Surgery |
Excellent 9/15 (60%) |
Good 6/15 (40%) |
Moderate 0/15 (0.0%) |
Total N=15 |
Minor |
4 |
1 |
0 |
5 |
Major |
5 |
5 |
0 |
10 |
Dosing was individualized based on incremental recovery results performed before surgery.
Mean total 12 to 24 preoperative dose was 50.9 IU/kg (median 55.0 IU/kg; range 36.1 to
59.9 IU/kg).
Mean total loading dose (1 hour preoperative dose) per infusion was 38.6 IU/kg (median
35.8 IU/kg; range 8.0 to 82.7 IU/kg). Major surgeries required a mean loading dose of
42.8 IU/kg (median 37.6 IU/kg; range 15.7 to 82.7 IU/kg) in comparison with a mean loading
dose of 30.2 IU/kg (median 34.2 IU/kg; range 8.0 to 46.4 IU/kg) for minor surgeries.
For subjects treated with VONVENDI (with or without ADVATE), the median total postoperative dose
within the first 7 days after surgery was 114.2 IU/kg with a range of 23.8 to 318.9 IU/kg (n=13)
and 76.2 IU/kg with a range of 23.8 to 214.4 IU/kg for the next 7 postoperative days (n=8).
REFERENCES
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