U.S. patent application number 17/513079 was filed with the patent office on 2022-04-21 for method of preventing of systemic-to-pulmonary-artery shunt thrombosis.
This patent application is currently assigned to Chiesi Farmaceutici S.p.A.. The applicant listed for this patent is Chiesi Farmaceutici S.p.A.. Invention is credited to Thomas Diacovo.
Application Number | 20220117994 17/513079 |
Document ID | / |
Family ID | 1000006066410 |
Filed Date | 2022-04-21 |
United States Patent
Application |
20220117994 |
Kind Code |
A1 |
Diacovo; Thomas |
April 21, 2022 |
METHOD OF PREVENTING OF SYSTEMIC-TO-PULMONARY-ARTERY SHUNT
THROMBOSIS
Abstract
The present invention is directed to the use of cangrelor for
the treatment and/or prevention of shunt thrombosis in patients
suffering congenital heart diseases undergoing shunt surgery. The
invention is also directed to the use of cangrelor for the
treatment and/or prevention of stent thrombosis in pediatric
patients undergoing stent implantation.
Inventors: |
Diacovo; Thomas; (Larchmont,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chiesi Farmaceutici S.p.A. |
Parma |
|
IT |
|
|
Assignee: |
Chiesi Farmaceutici S.p.A.
Parma
IT
|
Family ID: |
1000006066410 |
Appl. No.: |
17/513079 |
Filed: |
October 28, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16609800 |
Oct 31, 2019 |
11260071 |
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PCT/EP2018/066817 |
Jun 22, 2018 |
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17513079 |
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62524102 |
Jun 23, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 31/7076 20130101;
A61K 9/0019 20130101; A61K 9/0053 20130101; A61P 7/02 20180101 |
International
Class: |
A61K 31/7076 20060101
A61K031/7076; A61P 7/02 20060101 A61P007/02; A61K 9/00 20060101
A61K009/00 |
Claims
1. A method of treating or preventing shunt thrombosis in a patient
comprising administering a pharmaceutical composition comprising
cangrelor to the patient wherein the patient is suffering from
congenital heart diseases.
2. The method of claim 1 wherein the patient is undergoing shunt
surgery.
3. The method of claim 2 wherein the shunt surgery is selected from
the group consisting of systemic-to-pulmonary artery shunt,
Blalock-Taussing shunt, central shunt, and right ventricle to
pulmonary artery palliative shunts.
4. The method of claim 3 wherein the shunt surgery is
systemic-to-pulmonary artery shunt surgery.
5. (canceled)
6. The method of claim 1 wherein the patient is undergoing shunt
surgery or stent implantation.
7. The method of claim 6 wherein the shunt surgery or stent
implantation is selected from the group consisting of
systemic-to-pulmonary artery shunt, Blalock-Taussing shunt, central
shunt, right ventricle to pulmonary artery palliative shunt, and
ductus arterious stent.
8. The method of claim 7 wherein the patients suffer single
ventricle physiology palliated with systemic-to-pulmonary artery
shunt.
9. The method of claims 1 wherein the administration is
intravenous.
10. The method of claim 1 wherein the intravenous administration is
a continuous infusion.
11. The method of claim 10 wherein the amount of cangrelor
administered is between about 0.1 and about 4 .mu.g/kg/min.
12. The method of claim 11 wherein the amount of cangrelor
administered is between about 0.1 .mu.g/kg/min and about 1.5
.mu.g/kg/min.
13. The method of claim 12, wherein the point in time when the
pharmaceutical composition is administered is between about half an
hour and about 24 hours from the termination of the shunt surgery
or stent implantation.
14. The method of claim 13, wherein the point in time when the
pharmaceutical composition is administered is between about 2 and
about 4 hours from the termination of the shunt surgery or stent
implantation.
15. A method for preventing and/or treatment of shunt or stent
thrombosis comprising: i) performing the shunt surgery or stent
implantation; and ii) administering a composition comprising
cangrelor after the surgery.
16. The method according to claim 15 wherein the composition is
administered as a bolus, or as a continuous infusion, or as a bolus
followed by a continuous infusion, or as a continuous infusion
followed by a bolus.
17. The method according to claim 15 wherein the composition is
administered as a continuous infusion for at least about 10 minutes
to about 72 hours or until administration of an oral agent for
prevention of platelet aggregation.
18. The method according to claim 17 wherein the composition is
administered as a continuous infusion for at least about 10 minutes
to about 2 hours.
19. A method of treatment of a patient comprising administering a
pharmaceutical composition comprising cangrelor to the patient
wherein the patient is undergoing shunt surgery or shunt
implantation and then administering oral antiplatelet therapies to
the patient.
20. The method of claim 19 wherein the shunt surgery or stent
implantation is selected from the group consisting of
systemic-to-pulmonary artery shunt, Blalock-Taussing shunt, central
shunt, right ventricle to pulmonary artery palliative shunt, and
ductus arterious stent.
21. The method of claim 20 wherein the administration further
comprising: i) the administering a continuous infusion of cangrelor
after shunt surgery or stent implantation for at least one hour or
longer; ii) discontinuing the treatment with cangrelor; and iii)
administering the oral antiplatelet therapy.
22. The method of claim 21 wherein the continuous infusion of
cangrelor is at dosage between about 0.1 and about 4
.mu.g/kg/min.
23. The method of claim 22 wherein the continuous infusion is
between about 0.1 and about 1.5 .mu.g/kg/min.
24. The method of claim 22 wherein the continuous infusion is
between about 0.1 and about 1 .mu.g/kg/min.
25. The method of claim 22 wherein the continuous infusion is
between about 0.1 and about 0.5 .mu.g/kg/min.
26. The method of claim 22 wherein the continuous infusion is
between about 0.1 and about 0.3 .mu.g/kg/min.
27. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Ser. No.
62/524,102, filed on Jun. 23, 2017, the entire contents of which
are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] The invention pertains to the field of thromboprophylaxis
and particularly to preventing stent thrombosis in pediatric
patients, including neonates, and preventing shunt thrombosis in
high risk patients undergoing systemic-to-pulmonary artery shunt
surgery. Neonates with cyanotic congenital heart disease palliated
with a systemic-to-pulmonary artery shunt are at high risk of
thrombosis.
BACKGROUND OF THE INVENTION
[0003] Congenital heart defects (CHD) are the most common type of
birth defect. It affects 8 out of every 1,000 newborns and has a
wide range of disease severity. However, the majority of those born
with structural heart anomalies are otherwise healthy, and
corrective procedures may result in a normal lifespan (Monagle,
2005). While great technical advances have been achieved in
palliative and corrective measures and in the care of critically
ill neonates, these procedures are associated with an increased
risk of acute thrombotic events (ATE) in this patient population
(Monagle, 2004; Tormene et al., 2006; Monagle et al., 2008;
Manlhiot et al., 2011).
[0004] Palliation with a modified BT shunt is indispensable for the
management of a select group of neonates with cyanotic congenital
heart disease. However, such patients are at high risk for
thrombotic complications such as acute shunt occlusion, which
remains a major source of morbidity and mortality. Although aspirin
therapy, in general, is thought to reduce the risk of shunt
occlusion and improve survival, it is typically not administered
until 12 to 24 hours after surgery. A limited retrospective review
of pediatric cardiac patients with evidence of shunt occlusion at
Columbia University Medical Center revealed that the majority of
cases occurred prior to the administration of an antiplatelet
agent, establishing an unmet need for thromboprophylaxis during
this vulnerable period.
[0005] Acute thromboembolic events (ATE) are rapidly becoming the
new epidemic in centers that care for critically ill neonates due
to an increase in invasive monitoring, lifesaving technologies such
as extracorporeal membrane oxygenation (ECMO), and new surgical
techniques and graft materials used to repair complex congenital
heart disease. (Monagle P, Newall F, Barnes C, Savoia H, Campbell
J, Wallace T, Crock C. "Arterial thromboembolic disease: a
single-centre case series study." J Paediatr Child Health. 2008;
44:2832; Tormene D, Gavasso S, Rossetto V, Simioni P. "Thrombosis
and thrombophilia in children: a systematic review." Semin Throm.
Hemost. 2006; 32:724-728; Manlhiot C, Menjak I B, Brandao L R,
Gruenwald C E, Schwartz S M, Sivarajan V B, Yoon H, Maratta R,
Carew C L, McMullen J A, Clarizia N A, Holtby H M, Williams S,
Caldarone C A, Van Arsdell G S, Chan A K, McCrindle B W. "Risk,
clinical features, and outcomes of thrombosis associated with
pediatric cardiac surgery." Circulation. 2011; 124:1511-1519;
Chalmers E A. "Pediatric thrombosis." J Clin Pathol. 2000;
53:419-423.) In the latter case, infants (<6 months) constitute
the major proportion (.about.70%) of patients seen in tertiary care
centers with ATEs. (Monagle P. "Anticoagulation in the young."
Heart. 2004; 90:808-812.) In particular, those with single
ventricle physiology who require a systemic-to-pulmonary artery
shunt placement (e.g. modified Blalock-Taussing or central shunts)
are at greatest risk, especially in the early postoperative period.
(Manlhiot C, Menjak I B, Brandao L R, Gruenwald C E, Schwartz S M,
Sivarajan V B, Yoon H, Maratta R, Carew C L, McMullen J A, Clarizia
N A, Holtby H M, Williams S, Caldarone C A, Van Arsdell G S, Chan A
K, McCrindle B W. "Risk, clinical features, and outcomes of
thrombosis associated with pediatric cardiac surgery." Circulation.
2011; 124:1511-1519; Fenton K N, Siewers R D, Rebovich B, Pigula F
A. "Interim mortality in infants with systemic-to pulmonary artery
shunts." Ann Thorac Surg. 2003; 76:152-156; Monagle Paul.
"Thrombosis in children with BT shunts," Glenns and Fontans. Prog
Pediatr Cardiol. 2005; 21:17-21; Al Jubair K A, Al Fagih M R, Al
Jarallah A S, Al Yousef S, Ali Khan M A, Ashmeg A, Al Faraidi Y,
Sawyer W. "Results of 546 Blalock-Taussig shunts performed in 478
patients." Cardiol Young. 1998; 8:486-490.) Consequently, this has
resulted in suboptimal postoperative outcomes as exemplified in a
retrospective review of 2,058 neonates who underwent palliation
with a systemic-to-pulmonary artery shunt at multiple centers;
discharge mortality and complication rates were around an aggregate
of 6.7% and 12.3%, respectively. (Heidari-Bateni G, Norouzi S, Hall
M, Brar A, Eghtesady P. "Defining the best practice patterns for
the pediatric systemic-to-pulmonary artery shunt procedure." J
Thorac Cardiovasc Surg. 2014; 147:869-873.) Early institution of
aspirin, an irreversible inhibitor of platelet cyclooxygenase,
within 12 hours of surgery has reduced the risk of shunt thrombosis
and death in this patient population. (Al Jubair K A, Al Fagih M R,
Al Jarallah A S, Al Yousef S, Ali Khan M A, Ashmeg A, Al Faraidi Y,
Sawyer W. Results of 546 "Blalock-Taussig shunts performed in 478
patients." Cardiol Young. 1998; 8:486-490; Heidari-Bateni G,
Norouzi S, Hall M, Brar A, Eghtesady P. "Defining the best practice
patterns for the pediatric systemic-to-pulmonary artery shunt
procedure." J Thorac Cardiovasc Surg. 2014; 147:869-873; Li J S,
Yow E, Berezny K Y, Rhodes J F, Bokesch P M, Charpie J R, Forbus G
A, Mahony L, Boshkov L, Lambert V, Bonnet D, Michel-Behnke I,
Graham T P, Takahashi M, Jaggers J, Califf R M, Rakhit A, Fontecave
S, Sanders S P. "Clinical outcomes of palliative surgery including
a systemic-to-pulmonary artery shunt in infants with cyanotic
congenital heart disease: docs aspirin make a difference?"
Circulation. 2007; 116:293-297; Motz R, Wessel A, Ruschcwski W,
Bursch J. "Reduced frequency of occlusion of aorto-pulmonary shunts
in infants receiving aspirin." Cardiol Young. 1999; 9:474-477).
However, there remains an urgent need for pharmacologic protection
prior to the administration of an oral antiplatelet agent in order
to minimize the period during which patients are vulnerable to an
ATE.
[0006] Thienopyridines (e.g. clopidogrel) are a class of
antiplatelet agents that target the ADP receptor P2Y12 and are
known to reduce the risk of ischemia and thrombosis in adult
patients during and after percutaneous coronary intervention (PCI).
They do so by impairing P2Y12 potentiation of platelet dense
granule secretion in response to strong agonists, stabilization of
platelet aggregates by contributing to the activation of
.alpha.IIb.beta.3, and inhibition of the antiplatelet effects of
prostacyclin. Despite its proven clinical efficacy, clopidogrel has
several major drawbacks that would limit it use during the
vulnerable period for post-operative pediatric cardiac patients.
These include the requirement for oral administration that may
result in erratic absorption particularly in bypass cases, delay in
the onset of action due to the need for conversion of the pro-drug
to an active metabolite, and irreversible inhibition of P2Y.sub.12
that would necessitate platelet transfusion(s) if bleeding
occurred
[0007] Interestingly, a previous clinical trial evaluating
clopidogrel therapy in infants with cyanotic congenital heart
disease palliated with a systemic-to-pulmonary-artery shunt failed
to show any benefit in reducing the rate of death or shunt-related
morbidity in drug treated patients. In the majority of cases,
patients were also receiving aspirin therapy at the time of
administration of clopidrogrel. Of note, clopidrogrel is a prodrug
that requires metabolism by the liver to generate its active form,
which was unknown at the time that study was performed. It is also
an irreversible inhibitor of the P2Y12 receptor. Target value for
platelet inhibition in that trial was .about.30% as determined by
LTA. One major conclusion drawn from this study was that platelets
from these young patients might be less responsive to agonists such
as ADP as evidenced by the lower dose of clopidogrel needed to
achieve similar levels of inhibition of platelet aggregation using
LTA as compared to adults. This suggested that the P2Y12 signaling
pathway may be developmentally regulated and/or of less importance
in supporting thrombus generation in this population as compared to
adults.
[0008] Cangrelor, an adenosine triphosphate (ATP) analogue, is a
P2Y12 receptor antagonist given intravenously with properties more
suitable for short-term use, which include a rapid, direct,
predictable, and reversible inhibition of platelet function. It
does not require conversion to an active form as compared to
clopidogrel. It has a half-life of 3 to 6 minutes in adults with
restoration of hemostasis, as assessed by bleeding time, seen
within 10 minutes of cessation of infusion of a supratherapeutic
dose and full platelet function recovery within 60 minutes as
determined by response to ADP.
[0009] The alternatives forms and salts of cangrelor, processes for
their production, and pharmaceutical compositions comprising them,
are well known in the art and set forth, for example, in U.S. Pat.
No. 5,721,219. Additional disclosure relevant to the production and
use of cangrelor may be found in U.S. Pat. Nos. 5,955,447;
6,130,208; 6,114,313; 8,680,052; 759,316; 9,295,687; 9,427,448;
9,439,921; and 9,700,575.
[0010] Cangrelor is also rapidly inactivated by dephosphorylation
to the nucleoside. On the basis of these characteristics, it was
selected for clinical development as an IV antithrombotic agent and
has recently been approved by the FDA for use in adults undergoing
PCl.
[0011] Cangrelor may also have value as a potential bridging agent
to oral therapy in neonates with cyanotic congenital heart disease
who require palliation with a systemic-to-pulmonary-artery
shunt.
[0012] Despite advances in adjunctive pharmacotherapy, there
remains an urgent need for pharmacologic protection prior to the
administration of an oral antiplatelet agent in order to minimize
the period immediately after surgery during which patients, in
particular the pediatric patients, are vulnerable to an acute
thrombotic event (ATE).
[0013] We provide a pharmaceutical composition comprising a
P2Y.sub.12 inhibitor as anti-platelet agents for use in preventing
and/or treating thrombosis, having pharmacological properties that
are well suited for critically ill pediatric and pediatric patients
with congenital heart disease requiring thromboprophylaxis.
SUMMARY OF THE INVENTION
[0014] The present invention is directed to a use of cangrelor in
the treatment and/or prevention of shunt thrombosis in patients
suffering congenital heart disease. Additionally, the present
invention is directed to the use of cangrelor in the treatment
and/or prevention of shunt or stent thrombosis in pediatric
patients undergoing shunt surgery or stent implantation
respectively. Another aspect of the invention provides a
pharmaceutical composition comprising cangrelor for use in patients
suffering congenital heart disease undergoing shunt surgery.
[0015] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in the treatment and/or
prevention of shunt thrombosis in patients undergoing shunt surgery
wherein the shunt surgery is selected from the group including
systemic-to-pulmonary artery shunt, Blalock-Taussing shunt, central
shunt, or right ventricle to pulmonary artery palliative
shunts.
[0016] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in patients undergoing
systemic-to-pulmonary artery shunt surgery.
[0017] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in the treatment and/or
prevention of shunt or stent thrombosis in pediatric patients
suffering congenital heart disease.
[0018] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in the treatment and/or
prevention of shunt or stent thrombosis in pediatric patients
undergoing shunt surgery or stent implantation surgery.
[0019] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in pediatric patients
undergoing shunt surgery or stent implantation wherein the shunt
surgery or stent implantation is selected from the group including
systemic-to-pulmonary artery shunt, Blalock-Taussing shunt, central
shunt, right ventricle to pulmonary artery palliative shunts, or
ductus arterious stents.
[0020] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in pediatric patients
wherein the pediatric patients suffer single ventricle physiology
palliated with systemic-to-pulmonary artery shunt.
[0021] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in the treatment and/or
prevention of shunt or stent thrombosis wherein the administration
is intravenous. The patient population for shunt thrombosis
prevention and/or treatment is adult and pediatric patients,
including neonate. The patient population for stent thrombosis
prevention and/or treatment is pediatric patients, including
neonates.
[0022] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in the treatment and/or
prevention of shunt or stent thrombosis wherein the method
comprises:
i) performing the shunt surgery or stent implantation; ii)
administering the composition comprising cangrelor after
surgery.
[0023] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor wherein the composition is
administered as a bolus, or as a continuous infusion, or as a bolus
followed by a continuous infusion, or as a continuous infusion
followed by a bolus.
[0024] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for the above indications, wherein
the amount of cangrelor administered as continuous infusion is
between about 0.1 and about 4 .mu.g/kg/min. Preferably, the amount
of cangrelor is between about 0.1 and 1.5 .mu.g/kg/min, more
preferably between about 0.1 and 1 .mu.g/kg/min, even more
preferably from about 0.1 and 0.5 .mu.g/kg/min, where still more
preferred amount is between about 0.1 and 0.3 .mu.g/kg/min.
[0025] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use as a bridging agent to
oral antiplatelet therapies in pediatric patients undergoing shunt
surgery or stent implantation.
[0026] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use as a bridging agent to
oral antiplatelet therapies in pediatric patients undergoing shunt
surgery or stent implantation wherein the shunt surgery or stent
implantation is selected from the group including
systemic-to-pulmonary artery shunt, Blalock-Taussing shunt, central
shunt, right ventricle to pulmonary artery palliative shunts or
ductus arterious stents.
[0027] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use as a bridging agent to
oral antiplatelet therapies in pediatric patients undergoing shunt
surgery or stent implantation, wherein the administration
comprises:
i) administering a continuous infusion of cangrelor after shunt
surgery or stent implantation for at least one hour or longer; ii)
discontinuing the treatment with cangrelor; iii) administering the
oral antiplatelet therapy.
[0028] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use as a bridging agent
wherein the continuous infusion of cangrelor is preferably carried
out at a dosage as above defined.
[0029] Another aspect of the invention provides a pharmaceutical
composition comprising cangrelor for use in preventing acute stent
thrombosis in patients undergoing orthotopic heart transplant.
[0030] Another aspect of the invention provides a method of
preventing shunt thrombosis in high risk pediatric patients
undergoing systemic-to-pulmonary artery shunt surgery.
[0031] Another aspect of the invention is a method of preventing
shunt thrombosis in a high risk patient undergoing
systemic-to-pulmonary artery shunt surgery, the method
comprising:
i) performing systemic-to-pulmonary artery shunt surgery and ii)
administering cangrelor immediately after surgery.
[0032] The high risk patient preferably is a pediatric patient,
most preferably a neonate.
DETAILED DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1. Time from surgery to shunt occlusion in pediatric
cardiac patients. The data represent postoperative in-hospital
population from 2013 to 2015. Dotted line denotes the time aspirin
(ASA) is typically given by enteral route.
[0034] FIG. 2. P2Y12 receptor expression and ADP response of
platelets. A representative flow cytometry histograms of antibody
staining for the P2Y12 receptor on resting platelets isolated from
pediatric cardiac patients (NCP) versus healthy adults (n=5
independent experiments). Histograms of antibody staining for
GPIb.alpha. (CD42b) and integrin .alpha.IIb.beta.3 (CD61) are shown
for comparison. B-E, Concentration response curves for the
determination of EC50 values for ADP as measured by light
transmission aggregometry (LTA) using purified platelets from
pediatric and pediatric patients with congenital heart disease or
healthy adult volunteers in the presence of fibrinogen. Results are
the mean .+-.SEM; n=4-6 individuals for each concentration of ADP
tested.
[0035] FIG. 3. Effect of cangrelor on platelet aggregation in
response to ADP. A-D, Representative tracings of ADP (20
.mu.M)-induced aggregation of platelets isolated from pediatric and
pediatric patients with congenital heart disease or healthy adult
volunteers in the presence of indicated concentrations of
cangrelor.
[0036] FIG. 4. IC50 curves for cangrelor using LTA and a
microfluidic device. Concentration response curves for the
determination of IC50 values for 20 .mu.M ADP (A-D) and 5 .mu.M ADP
(E-H) as measured by LTA using purified platelets from pediatric
and pediatric patients with congenital heart disease or healthy
adult volunteers in the presence of fibrinogen. Data represent the
mean .+-.SEM. n=4-6 individuals for each concentration of
antagonist tested. I-J, Concentration response curves for cangrelor
under flow conditions. A microfluidic device containing a
thrombogenic surface of collagen was used to determine IC50 values
for cangrelor added to PPACK-treated whole blood from pediatric
patients with single ventricle physiology (n=4; 38 separate
clotting events) or healthy adults (n=7; 56 separate clotting
events). Data represent the mean .+-.SEM.
[0037] FIG. 5. Human platelet interactions with plasma VWF in flow.
A, Accumulation of human platelets on surface-immobilized VWF
obtained from mice possessing the human A1 domain (VWFHA1). Whole
blood from pediatric patients with single ventricle physiology or
healthy adults was infused over the reactive substrate for 3 min
(wall shear rate of 1,600 s-1) before assessing the number of
interacting platelets. mAb 6D1 is a function blocking antibody to
VWF receptor on platelets GPIb.alpha.. C, The ability human
platelets translocating on surface-immobilized mouse plasma VWFHA1
to undergo firm adhesion and arrest in response to ADP stimulation.
Abciximab is a function blocking antibody to integrin
.alpha.Ilb.beta.3, which is required for firm adhesion. Data
represent the mean .+-.SEM (n=5 individuals per group).
[0038] FIG. 6. Effect of cangrelor on human platelet thrombus
formation in avatar mice. Time course of the average size of
thrombi formed (A-D) and maximal thrombus size obtained (E) in
laser-injured arterioles of VWFHA1 mutant mice pre- and
post-administration of cangrelor (same animal). The effects of the
.alpha.IIb.beta.3 inhibitor abciximab (0.25 .mu.g/kg bolus; 0.125
.mu.g/kg/min infusion) are shown for comparison (n=3 independent
experiments for each age group). Each symbol (E) represents the
area of a thrombus in 1 arteriole of a mouse. Results for cangrelor
are the mean .+-.SEM of 8 independent experiments performed for
each age group of pediatric patients with CHD or healthy adult
volunteers. F, Percent change in thrombus size in response to
cangrelor treatment based on data shown in E. Data are from
represent mean .+-.SEM.
[0039] FIG. 7. Pharmacodynamic properties of cangrelor administered
to neonates with CHD in the early post-operative period. A phase 1
clinical trial is currently being conducted to assess the drug
plasma levels and effects on platelet aggregation using LTA and
microfluidics. A, representative LTA results from a post-operative
neonate with shunt placement 1 h prior to receiving cangrelor, 15
minutes prior to the end of the infusion (0.5 microgram/kg/min for
1 h), and 1 h after stopping the infusion of cangrelor. B,
microfluidic results under the same conditions as outlined for LTA.
Results are compared to a healthy adult who did not receive
cangrelor.
DETAILED DESCRIPTION OF THE INVENTION
[0040] The present invention is directed to use of cangrelor for
preventing and/or treating shunt thrombosis in a patient suffering
congenital heart disease. In one embodiment, the patients are
pediatric patients having cyanotic heart diseases.
[0041] The invention is thus directed to the use of cangrelor for
preventing and/or treating shunt or stent thrombosis in a high-risk
patient undergoing surgery for placement of palliative shunts or
implantation of a stent. Typically, the surgery includes the
placement of systemic to pulmonary shunts, Blalock-Taussing shunt,
central shunts, right ventricle to pulmonary artery palliative
shunts or ductus artcrious stents. Advantageously according to the
method of the present invention, the cangrelor is administered
after surgery according to the above preferred embodiments, thus
reducing the risk of acute thromboembolic events, particularly in
pediatric patients.
[0042] As before reported, the patients undergoing the above
mentioned shunt surgery or stent implantation, are at a high risk
for thrombotic complications such as, without limitation, acute
shunt occlusion, which remains a major source of morbidity and
mortality.
[0043] It has to be noted that the well known and widely used
aspirin therapy may help in reducing the risk of shunt occlusion,
but it is typically not administered until 12 to 24 hours after
surgery; therefore there is a vulnerable period immediately after
surgery or implantation up to the administration of aspirin wherein
the risk of onset of acute thromboembolic events is not managed. To
date, there are no other antiplatelet therapies available that
possess the desired characteristics of cangrelor, which include
i.v. administration, rapid onset, rapid reversibility, and a form
that does not require metabolic transformation for blockade of the
P2Y12 receptor. These characteristics are ideal for this patient
population that are both high risk for clot formation and bleeding
in the early post-operative period.
[0044] The method of the present invention provides an efficacious
method of treatment and/or prevention of thrombotic complications,
particularly in pediatric patients, said method comprising the
administration of cangrelor, shortly after the termination of the
surgery, and in another embodiment, also in combination with an
oral antiplatelet therapy. According to the invention, cangrelor is
preferably administered intravenous by continuous infusion at a
dosage, as above detailed, which is well suited, tolerated and safe
also for pediatric patients.
[0045] In particular, the invention is directed to the use of
cangrelor for prevention and/or treatment of shunt thrombosis in a
high risk pediatric patients have single ventricle physiology
undergoing systemic-to-pulmonary artery shunt surgery.
DEFINITIONS
[0046] In each aspect of the present invention, the term
"cangrelor" encompasses the compound of Formula 1, as well as
tautomeric, enantiomeric and diastercomeric forms thereof, and
raccmic mixtures thereof, and pharmaceutically acceptable salts of
these compounds, including a tetrasodium salt.
##STR00001##
[0047] In the present application, unless otherwise provided, the
definition of pediatric patients includes individuals from birth to
about 18 years, or a length-based weight (per Broselow Tape) of 36
kg or less. Patients who are known to be less than about 18 years
of age but whose weight exceeds 36 kg may still be considered
pediatric patients given their chronological age; however weights
will then need to be estimated and adult dosages should be used.
Thus, the pediatric patients includes e.g.: newborns up to about
the first 28 days of life; newborns up to about 12 months;
pediatric patients from: up to about 18 years; about 1 to about 3
years, from about 3 to about 5 years, from about 6 to about 10
years, from about 11 to about 14 years, and from about 14 to about
18 years.
[0048] Congenital heart defects (CHD) or congenital heart disease
(CHD) are structural problems arising from abnormal formation of
the heart or major blood vessels. At least 18 distinct types of
congenital heart defects are recognized, with many additional
anatomic variations. The word "congenital" means existing at birth.
Congenital heart defects may be cyanotic or acyanotic.
[0049] Examples of common type of congenital heart disease are, but
are not limited to: Aortic Valve Stenosis (AVS), Atrial Septal
Defect (ASD), Coarctation of the Aorta (CoA), Complete
Atrioventricular Canal defect (CAVC), d-Transposition of the Great
Arteries, Ebstein's Anomaly ,Hypoplastic Left Heart Syndrome,
I-Transposition of the Great Arteries, Patent Ductus Arteriosus
(PDA), Pulmonary Atresia, Pulmonary Valve Stenosis, Single
Ventricle Defects, Tetralogy of Fallot, Total Anomalous Pulmonary
Venous Connection (TAPVC), Tricuspid Atresia, Truncus Arteriosus,
and Ventricular Septal Defect (VSD).
[0050] In the present description, unless otherwise provided, the
definition of shunt surgery includes, but is not limited to:
systemic-to-pulmonary artery shunts, Blalock-Taussing shunts,
central shunts, or right ventricle to pulmonary artery palliative
shunts.
[0051] In the present description, unless otherwise provided, the
definition of stent implantation or stent surgery includes, but is
not limited to ductus arterious stents.
DETAILED DESCRIPTION
[0052] In one aspect, the present invention demonstrates by means
of standard LTA, high throughput microfluidic devices, and novel
biological platforms that cangrelor is effective in preventing and
treating thrombus formation in high risk pediatric populations
suffering from congenital heart disease.
[0053] Platelet response to ADP and cangrelor was nearly identical
for all age groups tested (P>0.05) based on calculated EC50 and
IC50 values obtained by LTA.
[0054] The in vitro potency of cangrelor was further evaluated
using whole blood from pediatric patients with single ventricle
physiology and high throughput micro fluidic assays, which yielded
similar IC50 values. Consistent with these findings was the
observation that platelets from pediatric patients expressed
similar levels of the P2Y12 receptor as their adult
counterparts.
[0055] To demonstrate the therapeutic utility of cangrelor in a
biologically relevant model of thrombosis, we also evaluated the in
vivo behavior of platelets from neonates and older patients with
congenital heart disease in laser-injured arterioles of avatar mice
(mice that have been genetically modified to support human platelet
mediated hemostasis and thrombosis) before and immediately after
drug administration. In all cases, cangrelor given at doses
recommended for percutaneous coronary intervention (per 1 kg of
body weight) reduced thrombus size by >45% thereby preventing
vessel occlusion (P<0.0001).
[0056] To demonstrate the potential clinical utility of cangrelor,
we first assessed the reactivity of platelets from neonates with
cyanotic congenital heart disease, and in particular the
contribution of the P2Y.sub.12 receptor in supporting aggregation
and thrombus formation.
[0057] By using standard as well as novel in vitro and in vivo
based technologies, there were no significant differences in
platelet response to either ADP-induced aggregation or
cangrelor-mediated P2Y.sub.12 receptor blockade for neonates and
older pediatric patients with congenital heart disease as compare
to healthy adults. In fact, EC.sub.50 and IC.sub.50 values,
respectively, were nearly identical as determined by LTA using
purified platelets.
[0058] As demonstrated in the present Experimental section,
platelets from pediatric patients with cyanotic congenital heart
disease have a nearly identical response to ADP and P2Y.sub.12
receptor blockade as their adult counterparts. Cangrelor may prove
to be an effective antithrombotic drug with pharmacological
properties well suited for use in the immediate post-operative
period for neonates palliated with a systemic-to-pulmonary artery
shunts.
[0059] Although ex-vivo technologies such as flow cytometry,
aggregometry, and microfluidic devices can yield important
information concerning pediatric platelet function and drug
response, they cannot fully replicate the complex adhesion and
activation events critical for thrombus formation on the arterial
side of the circulation. To address this issue, we utilized an
avatar mouse model that better reflects the intravascular
environment in humans by permitting human but not mouse platelets
to support biologically relevant interactions at sites of vascular
injury.
[0060] In fact, the power of this biological platform in assessing
the antithrombotic properties of P2Y.sub.12 inhibitors such as the
thienopyridine derivative clopidogrel, was accomplished by
evaluating the ability of platelets isolated from drug treated
adults to support thrombus formation in laser-injured arterioles of
these animals. Consistent with this dependency on the P2Y.sub.12
receptor for maximal thrombus generation was the ability of
cangrelor to limit the ability of platelets from neonates and older
pediatric patients with congenital heart disease to support clot
growth and vessel occlusion. Advantageously, cangrelor did not
completely prevent platelet accumulation at sites of arteriole
injury as compared to integrin .alpha.IIb.beta.3 inhibitor
abciximab, which nearly abrogated platelet-vessel wall
interactions.
[0061] A previous clinical trial evaluating the P2Y.sub.12
inhibitor clopidogrel in infants with cyanotic congenital heart
disease palliated with a systemic-to-pulmonary artery shunt failed
to demonstrate any significant reduction in either mortality from
any cause or shunt-related morbidity.
[0062] In addition to the prevention of shunt thrombosis, there may
be other indications for the use of cangrelor in this high risk
population. Despite an overall improvement in survival after a
multistage palliative repair for hypoplastic left heart syndrome,
patients may ultimately require an orthotopic heart transplant.
However, it has been reported that as many as 25% of transplant
patients will develop cardiac allograft vasculopathy necessitating
coronary artery revascularization and stent placement as a
short-term palliative solution. In fact, a recent study has
suggested that PCI can be performed safely and effectively in this
patient population, and has value as part of an evolving strategy
to improve outcomes prior to re-transplantation. Cangrelor, which
has been shown to significantly reduce ischemic events during PCI
in adults with coronary artery disease without significantly
increasing the risk of severe bleeding, may play a role in
preventing acute stent thrombosis in these patients as well.
[0063] In one embodiment, the present invention is directed to the
use of cangrelor for the treatment and/or prevention of acute stent
thrombosis in pediatric patients undergoing or who have undergone
orthotopic heart transplant. These patients typically need coronary
artery revascularization and stent placement as a short-term
palliative solution.
[0064] Given that shunt thrombosis remains a major cause of
morbidity and mortality and that patients are at highest risk
during the initially palliation for single ventricle physiology, we
herein surprisingly present preclinical evidence that the
non-thienopyridine P2Y.sub.12 inhibitor cangrelor may fill a
critical therapeutic void in thromboprophylaxis. This is justified
based on the results reported in the present invention,
demonstrating that platelets from pediatric patients with cyanotic
congenital heart disease have a robust response to ADP and are
surprisingly as amenable to P2Y.sub.12 inhibition with cangrelor as
their adult counterparts. Moreover, these findings are not
restricted to pediatric shunt patients but appear to be independent
of age and type of cardiac lesion.
[0065] Unique to this study is the ability to establish the in vivo
efficacy of cangrelor using an avatar mouse model that permits the
evaluation of human platelet interactions with the injured vessel
wall, thus demonstrating that this P2Y.sub.12 inhibitor yields the
intended biological response.
[0066] In addition, in vitro data obtained from a phase 1 PK/PD
clinical trial involving the infusion of cangrelor at 0.5
.mu.g/kg/min or 0.25 .mu.g/kg/min for one hour in post-operative
neonates with CHD that required palliation with a systemic to
pulmonary artery shunt demonstrated both the efficacy and rapid
reversibility o f cangrelor as assessed by LTA and microfluidics
(FIG. 7).
[0067] The above nonclinical and clinical studies provide
compelling evidence for an efficacious use of cangrelor in the
prevention and/or treatment of shunt or stent thrombosis in
patients suffering congenital heart disease who require palliation
with a systemic to pulmonary artery shunt.
[0068] It is understood that all preferred groups or embodiments of
the present invention described above may be combined with each
other and apply as well mutatis mutandis.
[0069] In one aspect, the invention provides the use of cangrelor
in the prevention and/or treatment of shunt thrombosis in patients
suffering congenital heart disease undergoing shunt surgery. The
treatment and/or prevention of shunt thrombosis in high risk
patients undergoing shunt surgery comprises performing shunt
surgery and administering cangrelor immediately after surgery.
[0070] In another aspect, the invention provides the use of
cangrelor for the prevention and/or treatment of shunt or stent
thrombosis in pediatric patients with cyanotic congenital heart
disease palliated with a systemic-to-pulmonary artery shunt,
Blalock-Taussing shunt, central shunt, right ventricle to pulmonary
artery palliative shunts, and ductus arterious stents, wherein the
pediatric patients are at high risk for thrombotic complications.
The thrombotic complications or acute thromboembolic events such as
acute shunt occlusion remain a major source of morbidity and
mortality.
[0071] In a preferred embodiment, the invention provides the use of
cangrelor for prevention and/or treatment of shunt thrombosis in a
high risk pediatric patients undergoing systemic-to-pulmonary
artery shunt surgery. The pediatric patients have single ventricle
physiology.
[0072] In another aspect, the invention provides the use of
cangrelor for prevention and/or treatment of stent thrombosis in a
high risk pediatric patients palliated with a ductus arterious
stents.
[0073] In another aspect, the invention provides the use of
cangrelor to reduce the incidence and/or prevent the mortality in
high-risk patients undergoing a shunt surgery, wherein mortality
may be associated with acute thrombotic events. The high-risk
patients are pediatric patients with congenital heart disease. In
particular, the pediatric patients have single ventricle
physiology.
[0074] In another aspect, the invention provides the use of
cangrelor to reduce the incidence and/or prevent the mortality in
high-risk pediatric patients undergoing a stent surgery, wherein
mortality may be associated with acute thromboembolic events. The
high-risk patients are pediatric patients with congenital heart
disease.
[0075] The invention also provides pharmaceutical composition
comprising cangrelor for the administration once or according to a
dosing regimen wherein a number of doses are administered at
varying intervals of time for a given period of time.
[0076] Administration of pharmaceutical compositions comprising
cangrelor may be accomplished according to patient needs, for
example oral, sublingual, intranasal, intraocular, rectal,
transdermal, mucosal, topical or parenteral administration.
Parenteral modes of administration include without limitation,
intradermal, subcutaneous (s.c., s.q., sub-Q, Hypo), intramuscular
(i.m.), intravenous (i.v.), intraperitoneal (i.p.), intra-arterial,
intramedulary, intracardiac, intra-articular (joint), intrasynovial
(joint fluid area), intracranial, intraspinal, and intrathecal
(spinal fluids).
[0077] Any known device useful for parenteral injection or infusion
of drug formulations can be used in the methods of the present
invention.
[0078] In a preferred embodiment of the invention, the
administration is via parenteral, more preferably intravenous
administration, via a peripheral IV or central venous line.
[0079] When administered intravenously, the pharmaceutical
composition comprising cangrelor may be administered as a bolus, as
a continuous infusion, as a bolus followed by a continuous
infusion, or as a continuous infusion followed by a bolus.
[0080] In one embodiment the invention provides a pharmaceutical
composition comprising cangrelor wherein the point in time when the
pharmaceutical composition is administered is between about a half
an hour and about 24 hours from the termination of the shunt
surgery or stent implantation, such as at least about half an hour,
about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5
hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours,
and about 10 hours or longer from the termination of the shunt
surgery or stent implantation. Preferably, the administration is
after at least about 1 hour, more preferably in a period of time
comprised between about 2 and about 4 hours from the termination of
the shunt surgery or stent implantation.
[0081] Preferably, the pharmaceutical composition comprising
cangrelor is administered as continuous infusion. For example, the
pharmaceutical composition according to the invention may be
administered after the shunt surgery or stent implantation as a
continuous infusion for at least about 10 minutes to about 72
hours. Preferably, the administration continues for at least about
1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours,
about 6 hours, about 7 hours, about 8 hours, about 9 hours, or
about 24 hours or longer. More preferably, the infusion continues
for at least about 10 minutes to about 2 hours; still more
preferably, the infusion continues for at least one hour, or for a
short period of time such as less than about an hour, such as about
15 minutes, about 30 minutes or about 45 minutes depending for
example on the dosage, the age or the weight of the patients.
[0082] When the pharmaceutical composition comprising cangrelor is
administered as a bolus,
[0083] it is administered within a short period of time, such as
about two minutes or less, or about one minute or less, after shunt
surgery or stent implantation.
[0084] In one aspect of the present invention, cangrelor can be
administered before, during, and/or after shunt surgery or stent
implantation.
[0085] When administered as a bolus, cangrelor is administered at
dosage between about 5 .mu.g/kg and about 100 .mu.g/kg, preferably
between about 5 .mu.g/kg and about 40 .mu.g/kg, even more
preferably between about 10 .mu.g/kg and about 35 .mu.g/kg, still
more preferably between about 10 .mu.g/kg and about 30 .mu.g/kg.
For example, the pharmaceutical composition comprising cangrelor is
administered at about 5 .mu.g/kg, about 10 .mu.g/kg, about 15
.mu.g/kg, about 20 .mu.g/kg, about 25 .mu.g/kg, or about 30
.mu.g/kg.
[0086] In one embodiment, an intravenous dose of up to about 4
microgram/kg/min, can be administered about 2 to about 4 h after
shunt surgery or stent implantation and continued until the
preferred time of administration of an oral agent.
[0087] The composition may be administered once, twice, thrice or
more times a day.
[0088] In a further embodiment, the pharmaceutical composition
comprising cangrelor is administered once the acute thromboembolic
event is recognized or diagnosed, or at the onset of symptoms of
the acute thromboembolic event.
[0089] For example, the pharmaceutical composition may be
administered when symptoms of acute thromboembolic event are
observed. The pharmaceutical composition is administered within a
short period of time from the onset of symptoms of acute
thromboembolic event.
[0090] The short period of time may range from about one or about
two minutes to about one or about two hours.
[0091] In some embodiments, the method comprises administering the
pharmaceutical composition comprising cangrelor as a prophylaxis
against an acute thromboembolic event.
[0092] Patients appropriate for such prevention include pediatric
cardiac subjects who are undergoing shunt surgery or stent
implantation for placement of systemic-to pulmonary artery
palliative shunts (e.g., Blalock-Taussig or central shunt), right
ventricle to pulmonary artery palliative shunts, or ductus
arteriosus stents who are at risk of thrombotic events after repair
of structural congenital heart disease.
[0093] In another aspect, the present invention provides the
administration of pharmaceutical composition comprising cangrelor
for the treatment of shunt or stent thrombosis in pediatric
patients undergoing stent implantation or shunt surgery
concurrently or sequentially (before or after) with at least one
additional therapeutic agent.
[0094] The additional therapeutic agent may be, for example without
limitation, a P2Y12-receptor inhibitor such as an oral
P2Y12-receptor inhibitor, a glycoprotein IIb/IIIa inhibitor,
aspirin and heparin. Administering an oral antiplatelet therapies,
either concurrently or sequentially with the pharmaceutical
composition comprising cangrelor in pediatric patients undergoing
shunt surgery or stent implantation may also transition the patient
to chronic or maintenance treatment with the antiplatelet
inhibitor.
[0095] As mentioned above, the present invention also provides the
use of cangrelor as a bridging agent to oral antiplatelet therapies
in pediatric patients requiring a palliative systemic-to-pulmonary
artery shunt, Blalock-Taussing shunt, central shunt, right
ventricle to pulmonary artery palliative shunt or ductus arterious
stent.
[0096] In one embodiment, the cangrelor is useful for transitioning
pediatric patients from administration of cangrelor after shunt
surgery or stent implantation to administration of a chronic or
maintenance treatment with oral antiplatelet therapies, i.e. oral
P2Y12, or aspirin.
[0097] In a preferred embodiment, the pharmaceutical composition
comprising cangrelor is administered in a method comprising:
[0098] i) administering a continuous infusion of cangrelor after
shunt surgery or stent implantation for at least half an hour to
about 72 hours;
[0099] ii) discontinuing the treatment with cangrelor; and
[0100] iii) administering the oral antiplatelet therapy.
[0101] In a further embodiment, the use of cangrelor in a method
for transitioning pediatric patients from administration of
cangrelor after shunt surgery or stent implantation to
administration of a chronic or maintenance treatment with oral
antiplatelet therapies includes a continuous infusion of cangrelor
after shunt surgery or stent implantation at a dosage according to
the above indicated preferred ones.
[0102] Cangrelor can be administered alone or combined with various
pharmaceutically acceptable excipients.
[0103] The pharmaceutical composition of the present invention
comprises cangrelor, and may further comprise one or more
pharmaceutically acceptable excipients.
[0104] These pharmaceutical compositions may comprise one or more
pharmaceutically acceptable excipients including, but not limited
to, carriers, diluents, stabilizing agents, solubilizing agents,
surfactants, buffers, antioxidants, preservatives, tonicity agents,
bulking agents, lubricating agents, emulsifiers, suspcnding or
viscosity agents, fillers, disintegrating agents, binding agents,
wetting agents, lubricating agents, antibacterials, antibiotics,
antifungals, chelating agents, sweeteners, perfuming agents,
flavoring agents, coloring agents, administration aids, and
combinations thereof.
[0105] Particular excipients include, but are not limited to,
cornstarch or gelatin, lactose, sucrose, dextrose, microcrystalline
cellulose, kaolin, mannitol, sorbitol, dicalcium phosphate, sodium
chloride, alginic acid, croscarmellose sodium, sodium starch
glycolate, glycerol, ethanol, propylene glycol, polysorbate 80
(Tween-80.TM. ), poly(ethylene)glycol 300 and 400 (PEG 300 and
400), PEGylated castor oil (e.g. Cremophor EL), poloxamer 407 and
188, cyclodextrin or cyclodextrin derivatives (including HPCD
((2-hydroxypropyl)-cyclodextrin) and (2
hydroxyethyl)-cyclodextrin), hydrophilic and hydrophobic carriers,
and combinations thereof.
[0106] Hydrophobic carriers include, for example, fat emulsions,
lipids, PEGylated phospholipids, polymer matrices, biocompatible
polymers, lipospheres, vesicles, particles, and liposomes. In
certain embodiments, the pharmaceutical compositions may comprise
polyols, such as sorbitol, lactose, sucrose, inositol or
trehalose.
[0107] The pharmaceutical compositions of the present invention may
be formulated for the route by which they are administered to the
patients, which include solids, liquids, and suspensions. For
example, if the pharmaceutical composition is formulated for IV
administration, the pharmaceutical composition may comprise an
intravenous fluid, which includes, but is not limited to,
water-for-injection (WFI), physiological saline, 0.9% NaCl,
phosphate buffered saline, 5% dextrose in water, and 0.002%
polysorbate 80 in water or Ringer's.TM. solution.
[0108] Such compositions may comprise cangrelor in an amount of
about comprised between 0.10 and 200 .mu.g/mL.
[0109] If the pharmaceutical composition is formulated for
intramuscular administration, the pharmaceutical composition may
comprise an intravenous fluid, which includes, but is not limited
to, WFI, physiological saline, 0.9% NaCl, phosphate buffered
saline, and 5% dextrose in water.
[0110] If the pharmaceutical composition is formulated for oral
administration, the pharmaceutical composition may comprise
excipients that include, but are not limited to diluents (e.g.,
sodium and calcium carbonate, sodium and calcium phosphate, and
lactose), binding agents (e.g., acacia gum, starch, gelatin,
sucrose, polyvinylpyrrolidone (Povidone), sorbitol, tragacanth,
methylcellulose, sodium carboxymethylcellulose, hydroxypropyl
methylcellulose, and ethylcellulose), fillers (e.g., calcium
phosphate, glycine, lactose, maize-starch, sorbitol, or sucrose),
wetting agents, lubricating agents (e.g., metallic stearates,
stearic acid, polyethylene glycol, waxes, oils, silica and
colloidal silica, silicon fluid or tale), disintegrating agents
(e.g., potato starch, corn starch and alginic acid), flavouring
agents (e.g. peppermint, oil of wintergreen, fruit flavoring,
bubblegum, and the like), and coloring agents.
[0111] Excipients may also include coatings such as glyceryl
monostearate or glyceryl distearate, to delay absorption in the
gastrointestinal tract. For oral use, the pharmaceutical
composition may be made in the form of a tablet, capsule,
suspension or liquid syrup or elixir, wafers and the like.
[0112] The pharmaceutical compositions of the present invention may
be prepared by admixing cangrelor with the one or more
pharmaceutically acceptable excipients. Methods of admixing and
devices useful for admixing are known in the art.
[0113] In certain embodiments, cangrelor and the one or more
pharmaceutically acceptable excipients are dissolved and then
admixed. The resulting mixture may be dried, such as through
lyophilization, to form a solid pharmaceutical composition, or the
resulting mixture may remain in solution form as a liquid
pharmaceutical composition. In some embodiments, the solid
pharmaceutical composition may be solubilized in an intravenous
fluid before administration, for example, as a bolus or
infusion.
[0114] In some embodiments, the pharmaceutical composition is
prepared by dissolving and admixing cangrelor, mannitol, sorbitol,
and optionally sodium hydroxide, and then lyophilizing the mixture.
Prior to administration, the lyophilized mixture is dissolved in an
intravenous fluid such as WFI or physiological saline.
[0115] The following examples illustrate the invention, without any
limitation.
EXPERIMENTAL PART
Methods
Reagents
[0116] ADP and type 1 collagen (ChronoPar) were obtained from
Chronolog (Havertown, Pa.). Human fibrinogen was purchased from
Sigma Co. (Saint Louis, Mo.) and abciximab (ReoPro) from Centocor,
Inc (Marvin, Pa.). The polyclonal anti-VWF antibody and Alexa 488
conjugated antihuman CD61 (GPIIIa) antibody were purchased from
Dako (Carpinteria, Calif.) and Bio-Rad (Raleigh, N.C.; clone
Y2/51), respectively. MAb 6D1 (function blocking antibody to human
GPIb.alpha.) and cangrelor (P2Y12 inhibitor) were kindly provided
by Barry Coller (Rockefeller University, N.Y.) and The Medicine
Company (Parsippany, N.J.).
Mice
[0117] VWF.sup.HA1 mutant animals were generated and backcrossed 10
generations on a 129/SvJ background as previously described. All
procedures performed on animals were approved by The Institutional
Animal Care and Use Committees at Columbia University Medical
Center.
Patient population
[0118] Blood samples from 78 patients with CHD (neonates to 18
years) and healthy adults were collected to assess platelet
reactivity and response to cangrelor using light transmission
aggregometry (LTA), collagen-coated multichannel micro fluidic
devices, and genetically modified mice that support human but not
mouse platelet-mediated thrombosis (avatar mouse).
[0119] Patients were eligible for enrollment in the study if they
were 0 to 18 years of age and with known congenital heart disease.
Exclusion criteria included coagulation defects, known congenital
or genetic conditions expected to affect platelet function, body
weight <3 kg for pediatric patients and <6 kg for older
pediatric patients, cardiopulmonary instability necessitating
urgent or emergent surgical/catheter-based intervention,
medications or other conditions that might significantly affect
platelet function.
[0120] Seventy-eight pediatric patients with congenital heart
disease were enrolled in this study. Three different study
population groups were chosen (Table 1).
TABLE-US-00001 TABLE 1 Baseline Demographic Characteristics of
Cardiac Patients Baseline Characteristics 0-28 days 1-10 years
11-18 years No. 39 31 8 Mean age 12.8 4.1 15.3 Female, % patients
23.1 54.8 37.5 Ethnicity, % patients Hispanic/Latino 20.5 25.8 12.5
Race, % patients White 56.4 64.5 62.5 Black 7.6 6.5 12.5 Asian 15.5
3.2 12.5 Native American 0 0 0 Other 20.5 25.8 12.5 Mean
gestational age (weeks) 38 Diagnosis, % patients Hypoplastic left
heart syndrome 23.1 19.4 0 Pulmonary atresia with intact 0 3.2 0
ventricular septum Tricuspid atresia 0 6.5 0 Transposition of great
arteries 33.3 12.9 0 Tetralogy of Fallot 2.6 19.4 25 Double-inlet
left ventricle 5.1 3.2 0 Double-outlet right ventricle 0 3.2 12.5
Coarctation 12.8 3.2 12.5 PDA 0 12.9 0 ASD 0 0 25 Heterotaxy 7.7 0
0
[0121] The first included full-term neonates (0-28 days) with a
body weight of .gtoreq.3 kg scheduled for cardiac surgery involving
cardiopulmonary bypass. Of these, 56.4% were white, 7.6% were
black, 15.5% were Asian, 20.5% were of Hispanic/Latino ethnicity,
and 23.1% were female. Patients with single ventricle pathology
accounted for 23.1% of the population enrolled in the study, with
D-transposition of the great arteries accounting for the majority
of patients (33.3%). During this period of time, .about.23% of
neonates requiring palliation with a systemic-to-pulmonary shunt
had evidence of shunt occlusion necessitating a surgical
intervention and/or rapid response ECMO. Interestingly, all events
occurred within 24 hours of surgery with the majority of cases
prior to initiation of aspirin therapy, FIG. 1.
[0122] The second group included pediatric patients ranging in age
from 1-10 years (mean of 4.1 years) scheduled to undergo left heart
catheterization for diagnostic or therapeutic purposes; the third
group included adolescent patients ranging in age from 11-19 years
(mean of 15.3 years) also undergoing left heart
catheterization.
Blood Collection
[0123] For studies involving patients with congenital heart
disease, blood was obtained from a central venous catheter after
clearing the line of heparin; blood from healthy adult volunteers
was obtained via routine venipuncture. In the majority of cases,
3.8% trisodium citrate served as anticoagulant. For microfluidic
studies, whole blood was collected in a syringe containing the
thrombin inhibitor H-D-Phe-Pro-Arg-chloromethylketone (PPACK,
Calbiochem, San Diego, Calif.) to achieve a final concentration of
100 .mu.M. Generation of PRP or purified platelets was performed by
centrifugation as previously described.
Example 1
Platelet Aggregation Evaluation by Means of Light Transmission
Aggregometry (LTA)
[0124] In this Example, platelet reactivity and response to
cangrelor of pediatric patients and healthy adults was
examined.
[0125] Purified platelets were suspended to a final concentration
of 400,000/.mu.l in platelet buffer containing 145 mM NaCl, 10 mM
Hepes, 0.5 mM Na2HPO4, 5 mM KCl, 2 mM MgCl2, 1 mM CaCl2, 0.1%
glucose, pH 7.4. Stock solutions of cangrelor were prepared on the
day of experimentation and added to platelet suspensions (37
.beta.C, 1,200 rpm) 10 min prior to inducing aggregation with ADP
(5 .mu.M or 20 .mu.M ). Human fibrinogen (final concentration 200
.mu.g/ml) was added to the platelet suspensions just prior to
activation. Aggregation was assessed using a Chronolog
Lumi-Aggregometer (model 540 VS, Chronolog, Havertown, Pa.) and
permitted to proceed for 6 min after the addition of agonist. The
results are reported as maximum percent change in light
transmittance from baseline with platelet buffer used as a
reference.
Results
Response of Platelets to ADP
[0126] Conflicting results exists regarding the overall reactivity
of platelets from neonates with cyanotic congenital heart disease
as compared to their healthy counterparts and adults, especially in
response to physiologically relevant agonists such as ADP. It was
also unclear whether platelets from this high risk population are
as amenable to inhibition with antithrombotic drugs such the
P2Y.sub.12 receptor antagonists as those from adults.
[0127] To address these therapeutically relevant concerns, we first
evaluated the level of expression of the P2Y.sub.12 receptor on
platelets isolated from neonates with cyanotic congenital heart
disease. In comparison to platelets from adults, no discernible
difference in P2Y.sub.2 surface expression was detected (FIG. 2A);
similar results were obtained for the platelets receptors for VWF
(GPIb.alpha.) and fibrinogen (.alpha.IIb.beta.3), which are
indispensable for clot formation.
[0128] We next determine the functional response of platelets from
neonates as well as older patients with congenital heart disease to
ADP stimulation. This was accomplished by calculating EC.sub.50
values for the agonist using isolated platelets in
fibrinogen-supplemented buffer.
[0129] FIG. 2 (B through E) shows the mean (.+-.SEM) percent
platelet aggregation as a function of ADP concentration. Calculated
EC.sub.50 values were not significantly different for all age
groups tested with mean values (.+-.SEM) ranging from 2.9.+-.0.1
.mu.mol/L to 3.4.+-.0.1 .mu.mol/L (Table 2, P<0.001).
TABLE-US-00002 TABLE 2 EC.sub.50 and IC.sub.50 Values for ADP and
Cangrelor, respectively Platelets Adult 0-28 days 1-10 years 11-18
years EC.sub.50 .+-. SEM 3.2 .+-. 0.2 3.4 .+-. 0.1 2.9 .+-. 0.1 3.2
.+-. 0.2 (.mu.mol/L) IC.sub.50 .+-. SEM* 0.82 .+-. 0.3 0.82 .+-.
0.2 0.79 .+-. 0.2 0.85 .+-. 0.2 (nmol/L) IC.sub.50 .+-. SEM** 0.66
.+-. 0.3 0.74 .+-. 0.3 0.68 .+-. 0.3 0.76 .+-. 0.2 (nmol/L) *= 20
.mu.M ADP, **= 5 .mu.M ADP
Effect of Cangrelor on Platelet Aggregation
[0130] Cangrelor has been shown to be a potent inhibitor of
ADP-induced platelet aggregation in adults. To date, no information
exists on its ability to effectively mitigate the ADP response of
platelets from neonates with congenital heart disease. To this end,
we calculated IC.sub.50 values for this P2Y.sub.12 receptor
antagonist using low and high concentrations of ADP (5 .mu.M versus
20 .mu.M). Consistent with results obtained by flow cytometry and
in ADP-induced platelet aggregation studies, no statistical
difference was observed in the amount of cangrelor needed to
achieve half-maximal inhibition at either concentration of agonist
(FIG. 3A through D (20 .mu.M ADP), FIG. 4A through D (20 .mu.M
ADP), Figure E through H (5 .mu.M ADP); Table 1, P<0 .001).
Similarly results were observed for older populations of patients
with congenital heart disease.
Example 2
Platelet Adhesion in Flow Evaluation of Neonates with Single
Ventricle Physiology using Multichannel Microfluidic Device
[0131] In this Example, the platelet adhesion of neonates with
single ventricle physiology was examined by means of multichannel
micro fluidic device.
[0132] A parallel-plate flow chamber was used to assess platelet
accumulation on surface-immobilized plasma VWF at a wall shear rate
of 1,600 .sub.s-1.29, 31 In brief, a polyclonal anti-VWF antibody
was absorbed overnight (4.degree. C.) to a six-well tissue culture
plate. Subsequently, the plate was washed and nonspecific
interactions blocked by the addition of TBS containing 3% BSA, pH
7.4 (30 min, 37.degree. C.). Human or murine (VWF.sup.HA1) plasma
obtained from heparinized whole blood was added and the plates
placed at 37.degree. C. for an additional hour prior to use.
Citrated whole blood was then perfused over the reactive substrate
for 3 minutes, followed by the addition of platelet buffer lacking
CaCl2 for 1 min. The number of platelets attached per unit area was
determined by offline analysis (ImagePro Plus, Media Cybernetics,
Bethesda, Md.) of recorded digital images. For GPIb.alpha.
inhibition studies, mAb 6D1 (10 .mu.g/ml) was added to
anticoagulated human blood for 10 min before use.
[0133] Micro fluidic devices with 8 individual channels (250 .mu.m
wide.times.60 .mu.m-high) were fabricated in polydimethylsiloxane
(PDMS) as previously described. The device was reversibly
vacuum-sealed to a glass slide with its flow channels aligned
perpendicularly to a patterned type 1 collagen surface (1 mg/ml).
To visualize platelet accumulation over time, an Alexa Fluor 488
conjugated, non-function blocking mouse anti-human CD61
(GPIIb/IIIa) antibody was added (1:50 ratio) 7 min prior to
performing experiments (0.125 .mu.g/ml final concentration).
[0134] Whole blood from neonates with single ventricle pathology or
healthy adults was perfused over the prothrombotic surface at an
initial wall shear rate of 100 s.sup.-1 by withdrawal from a single
outlet into a syringe pump (Harvard Apparatus Pump 11 Elite,
Holliston, Mass.). Platelet accumulation was visualized (10.times.
objective lens) using an automated inverted microscope system
(DMI6000, Leica) equipped with a CCD camera (DFC365FX, Leica). A
custom stage insert held three microfluidic devices allowing
replicate testing of four conditions. Images were captured in 30 s
intervals for a total of 5 min. Platelet fluorescence intensities,
which are directly proportional to the total platelet mass were
measured and analyzed with Image J software (Image J; NIH,
Bethesda, Md.). The center 65% of the prothrombotic region was
selected for analysis to avoid edge effects. The initial image was
taken as background and subsequent images were background
corrected. Platelet adhesion and aggregate formation was not
observed upstream or downstream of the collagen trip prior to full
channel occlusion.
[0135] Calculation of half maximal inhibitor concentration and
Cangrelor sensitivity Background-corrected fluorescence values were
fitted with a 4 parameter dose-response model.
FI = A + A - B 1 + 10 [ ( Lo .times. .times. g .times. .times. IC
50 - C ) .times. D ] ##EQU00001##
where C represents the Cangrelor concentration; FI, the
background-corrected fluorescence of the corresponding region of
interest; A and B, the minimum and maximum intensities,
respectively; and D, the Hill coefficient. The data was fitted by a
log (inhibitor) vs. response routine in GraphPad Prism 5.00
(GraphPad Software, La Jolla, Calif.).
Results
[0136] Further evidence supporting the in vitro potency of
cangrelor in reducing the aggregation of platelets from neonates
with single ventricle physiology was provided in microfluidic
studies that recreate the hemodynamic conditions of thrombosis.
Whole blood collected in PPACK was treated with various
concentrations of cangrelor and then perfused over
surface-immobilized collagen. In each experiment, 8 simultaneously
forming thrombi per device were imaged in real time. Fluorescently
labeled platelets were observed to accumulate only at the site of
collagen exposure, with minimal non-specific upstream or downstream
adhesion. Determination of surface fluorescence at 300 s
(FI.sub.300s) permitted calculation of effective IC.sub.50 values,
which were 0.69 nM and 0.95 nM for neonates with CHD versus healthy
adults, respectively (FIG. 4I and J).
Example 3
In Vivo Thrombus Formation Evaluation from Pediatric and Older
Patients with Congenital Heart Disease
[0137] Administration of anesthesia, insertion of venous and
arterial catheters, fluorescent labeling of human platelets, and
surgical preparation of the cremaster muscle in 12 week old male
VWF HAI mice have been previously described.
[0138] Human platelets (700K/.mu.L) were continuously infused (25
.mu.l/min) through a catheter placed in the ipsilateral femoral
artery 2 min prior to and during laser-induced injury to ensure a
level of circulating cells equivalent to humans..sup.33 Injury to
the vessel wall of arterioles (40-65 .mu.m diameter) was performed
with a pulsed nitrogen dye laser applied through a 20.times.
water-immersion Olympus objective. Human platelet-vessel wall
interactions were visualized by fluorescence microscopy using a
system equipped with a Yokogawa CSU-22 spinning disk confocal
scanner, iXON EM camera, and 488-nm laser line (Revolution XD,
Andor Technology, South Windsor, Conn.) to detect
Calcein-AM-labeled cells, respectively. The extent of thrombus
formation was assessed for 3 min after injury and the maximal area
(.mu.m.sup.2) of coverage determined by off-line analysis (ImagePro
Plus, Media Cybernetics, Bethesda, Md.).
[0139] After establishing a baseline for normal thrombus generation
in injured arterioles, cangrelor was then given initially as an
intravenously bolus (30 .mu.g/kg) and then as a continuous infusion
(4 .mu.g/kg/min) as described in previously clinical trials.
[0140] A minimum o f 5 mice per patient group were studied (2 and 4
arterial segments pre and post-cangrelor per mouse,
respectively).
Statistics
[0141] To compare mean thrombus areas between different treatment
groups, we fit linear mixed models with random intercepts for each
study animal. Linear mixed models permit comparison of mean
differences between treatment groups while also considering the
effect of the clustering of the data on the SEs resulting from
multiple measurements obtained from each mouse used in intravital
studies. In the case of platelet aggregation studies, values are
presented as mean .+-.SEM. A 2-tailed Student t test was used for
comparisons between control conditions and treatments. Differences
with values of P<0.05 were considered statistically
significant.
Results
In Vivo Efficacy of Cangrelor
[0142] Previously, we have shown the preclinical utility of an
avatar mouse model that preferentially supports human and not mouse
platelet-mediated hemostasis and thrombosis.
[0143] This switch in species specificity for platelets resulted
from the incorporation of the R1326H single mutation into the A1
domain of mouse VWF (VWF.sup.R1326H), and more recently by
replacement of the entire domain with its human counterpart
(VWFHA1).
[0144] Of note, VWF mutant animals have a profound bleeding
phenotype due to the inability of mouse platelets to stably
interact with damaged vascular endothelium. As human platelet
interactions with VWF is key to the initiation of thrombus
formation in this avatar mouse model, we first evaluated the
ability of platelets from neonates with CHD to accumulate on
surface-immobilized human or murine VWF.sup.HA1 under arterial flow
conditions. Importantly, platelets from former accumulated on
plasma VWF from humans or VWF.sup.HA1 mutant mice at levels
comparable to those from healthy adults (FIG. 5A and B). Moreover,
no significance difference was observed in the number of platelets
from neonates that attached to either substrate (2,432.+-.55
platelets/mm.sup.2 versus 2,223.+-.156 platelets/mm.sup.2,
respectively; P=0.84). Importantly, this interaction could be
inhibited by the addition of the monoclonal antibody 6D1 that
blocks the ability of the platelet receptor GPIb.alpha. to interact
with the A1 domain of VWF.
[0145] Although GPIb.alpha. initiates platelet deposition at
arterial shear rates, this adhesive interaction is labile in nature
permitting platelets to translocate in response to forces generated
by flowing blood. Ultimately it is the platelet integrin receptor
.alpha.IIb.beta.3 that stabilizes adhesion by engaging with ligands
such as VWF in response to ADP and/or thrombin. Consistent with
this scenario is the ability of abciximab, an inhibitor of human
.alpha.IIb.beta.3, to prevent the firm adhesion of platelets from
pediatric patients with CHD or healthy adults to
surface-immobilized VWF in response to ADP-induced activation in
flow (FIG. 5C).
[0146] After establishing that plasma VWF.sup.HA1 supports
attachment as well as ADP-induced firm adhesion, we next set out to
determine the potential therapeutic effect of cangrelor in
preventing human platelet mediated thrombus in vivo. The dose and
route of administration of the drug was based on previous clinical
trials in adults undergoing PCI.
[0147] Fluorescently labeled human platelets were infused
continuously through a catheter inserted into the femoral artery
and their behavior in response to laser-induced arterial injury
monitored before and after administration of cangrelor. Consistent
with the requirement for ADP to promote a second wave of
aggregation, P2Y.sub.12 receptor blockade on platelets from
pediatric cardiac patients yielded a .about.45% reduction in
thrombus size (P<0.0001) (FIG. 6 A through F; see Table
III).
TABLE-US-00003 TABLE III Linear mixed model comparing average human
platelet thrombus size (.mu.m2) in VWFHA1 mutant mice. The contrast
column is the mean difference between thrombus size pre- and post-
administration of cangrelor for each age group tested. Standard
errors and statistics were obtained from fitting of the linear
mixed model. Age Contrast Standard group estimate error P-value
0-28 days 2,261 224 <0.0001 1-10 years 3,314 224 <0.0001
11-18 years 3,475 224 <0.0001 Adult 3,501 224 <0.0001
[0148] By contrast, administration of abciximab abrogated platelet
accumulation by >90% (P<0.0001). Similar results were
obtained using platelets from older patients with congenital heart
disease and healthy adults.
[0149] Various changes could be made in the above methods without
departing from the scope of the invention as defined in the claims
below. It is intended that all matter contained in the above
description, and as shown in the accompanying figures, shall be
interpreted as illustrative and not as limiting.
* * * * *