Transcript Development of Generic Low Molecular Weight Heparin

Generic low molecular weight
heparins. Are there any guidelines!
Jawed Fareed, Ph.D.
Walter Jeske, Ph.D.
Loyola University Medical Center
What are Generic Drugs?
A generic drug is identical, or bioequivalent to a
brand name drug in dosage form, safety,
strength, route of administration, quality,
performance characteristics and intended use.
Although generic drugs are chemically identical
to their branded counterparts, they are typically
sold at substantial discounts from the branded
price. According to the Congressional Budget
Office, generic drugs save consumers an
estimated $8 to $10 billion a year at retail
pharmacies.
Is a Generic Drug Available
for a Brand Name Drug?
• You can search for generic equivalents by using
the "Electronic Orange Book" at
http://www.fda.gov/cder/ob/default.htm and
search by proprietary "brand" name," then
search again by using the active ingredient
name. If other manufacturers are listed besides
the "brand name" manufacturer when searching
by the "active ingredient," they are the generic
product manufacturers.
• Generic versions of heparin, aspirin, warfarin
and streptokinase are available. In some
countries Generic versions of LMWHs are
available.
Manufacturing Process for Low Molecular Weight
Heparin and Lower Low Molecular Weight Heparin
Anti-Xa/IIa =
1.0
UFH
Anti-Xa/IIa = 2.5 7.5
Anti-Xa/IIa = 10 Heparin derived
15 kDa
- 50
oligosaccharides
< 2.5 kDa
LMWH
4-6 kDa
Ultra LMWH
Anti-Xa/IIa =
> 50
2-4 kDa
Depolymerization inflicts
other changes
Pentasaccharide
1-7 kDa
Currently Developed Generic
LMWHs
1. Enoxaparin
(Aventis, France)
2. Dalteparin
(Pfizer, USA)
3. Tinzaparin
(Leo, Denmark)
4. Parnaparin
(Opocrin, Italy)
Specific Structural Features in LMWHs
COO2-
CH2OSO3O
O
OH
O
O
O
OH
O
*
CO2OH
NHSO3-
OSO3-
O
O
OH
OSO3- n
NHSO3-
* C6H5CH2/Na+
Enoxaparin
CH2OSO3-
CH2OSO3O
O
CO2OH
O
OH
O
HO
OSO3-
NHSO3-
*
O
O
CO2OH
O
OSO3- n
OH
CH2OH
*C6H5CH2/Na+
Any generic product must exhibit similar structural features.
Fraxiparin
Is Chemical Characterization of
Branded LMWHs Sufficient to Satisfy
Assure Pharmacodymamics
Equivalence?
No. Because LMWHs are hybrid products
of biologic origin with chemical
modifications. Moreover the starting
material is more important to
characterize for product consistency.
Are LMWHs Different?
Chemical properties make each LMWH unique
This translates into pharmacological differences between LMWHs
This impacts the clinical safety and efficacy
in both arterial and venous thrombosis
Molecular Weight Distribution
ACLM
BCLM
Cumulative percentage
100
80
60
Enoxaparin
Certoparin
Parnaparin
Reviparin
Tinzaparin
Fraxiparin
Dalteparin
40
20
0
6
5
4
3
Molecular weight (Da)
2
ACLM = above critical length material; BCLM = below critical length material; Da = Daltons
The relative proportion of high molecular weight components clearly differs.
LMWH Differentiation:
Clinically Relevant Attributes
•
•
•
•
•
•
•
•
•
•
•
•
Structural differences ………….……. May impact PK/PD
Molecular size ………..………………. May impact anti-Xa, anti-IIa
Charge density …………………………Interaction with cells
Binding to ATIII ……………………….. Antithrombotic effects
Binding to HCII ………… ……………. Anticoagulant effects
Ability to release TFPI ………………..Inhibition of formed TF
Interaction with proteins …………….. Decreased PK/PD
Interactions with cells ……………….. Signaling effects (not understood)
Ability for glycosylation ……………… Biological amplification
Vascular uptake ……………………… Antithrombotic surface
Endovascular uptake ……………….. Inhibition of vascular proliferation
Modulation of growth factors ………...Anti-cancer, anti-apoptotic, antiangiogenic
• Molecular effects ……………………..Genotypic expression changes
• Regulatory effects…………………….Molecular and cellular effects
Key Issue
Generic drugs must contain the same active
ingredient as the innovator drug and must be
bioequivalent in terms of their PK/PD profile. While
straight-forward for small molecule drugs,
demonstrating sameness is much more difficult for
drugs whose active ingredients are complex
mixtures.
Are the current regulatory guidelines regarding the
characterization of LMWHs adequate to ensure
that generic LMWHs are, in fact, the same as the
innovator drug?
Ongoing Issues Related to the
Acceptance of LMW Heparins
1. Product classification by regulatory agencies
2. Development of new guidelines covering both
the biological and chemical characterization of
LMWHs
3. Citizen’s Petition from the branded
manufacturers
4. Reponses to the Citizen’s Petition from generic
suppliers
5. Court hearing on patents
6. Congressional discussions
7. Position of regulatory agencies
Current
Generics
Minimal Requirements For the
Considerations For A Generic LMW Product
1. Comparable Pharmacopoeial Monographs
2. Pharmacological and biochemical
characterization
3. Pharmacokinetic/Pharmacodynamic studies
(AUC)
Effect of Various LMWHs on Platelet P-Selectin Expression
Lovenox and generic enoxaparins exhibit varying potencies for inhibiting
thrombin-induced platelet P-selectin expression.
USP and Anti-Fxa Potency of Various Generic LMWHs
Relevance to TAFIa Generation Inhibition
120
100
100
Units/mg
80
60
60
40
40
20
20
0
0
Cutenox
Clenox
Dilutol
Dripanina
USP (U/mg)
IU/mg
TAFIa (% Activity)
Lovenox
TAFIa (% Activity)
80
Heparinase and Protamine Neutralization of Generic Dalteparin
*
**
Neutralization of Dalteparin and Daltehep by 0.1 U/ml heparinase-I (left) and 25 µg/ml protamine sulfate
(right). While heparinase neutralized the anticoagulant effect of Dalteparin and Daltehep to a
comparable level, protamine was not as effective at inhibiting Daltehep. *p<0.05 vs. Daltehep; **p<0.05
vs. Dalteparin + protamine
Enoxaparins + 0.125U/ml UFHase, UV
0.15
AU
0.10
0.05
0.00
31.0
33.0
35.0
37.0
39.0
41.0
43.0
Minutes
Lovenox
Gen 3
Gen 1
Gen 4
Gen 2
45.0
47.0
49.0
Pre- and Post-Heparinase Molecular Profile of Various
Versions of Enoxaparin
Comparative MW Profile of Generic LMWHs
UV
Comparative MW Profile of Generic LMWHs
UV detection
3500
80
% components < 2.5 kDa
3000
Mn (Da)
2500
2000
1500
1000
500
0
60
40
20
0
Enoxaparin
G-AE
G-AG
G-AJ
Pre-UFHase
0.125 U/ml UFHase
0.25 U/ml UFHase
G-AN
Enoxaparin
G-AE
G-AG
G-AJ
Pre-UFHase
0.125 U/ml UFHase
0.25 U/ml UFHase
G-AN
Differential Functionality of Pre- and Post-Heparinase Digested
Generic LMWHs
Anti-IIa 0.1 U/ml UFHase
Anti-IIa Pre-UFHase
80
100
60
% Inhibition
% Inhibition
80
60
40
40
20
20
0
0
1
10
100
Conc; µg/ml
1
10
Conc; µg/ml
Enox 89c141
Enox 89441
Sing. Enox
Cutenox 306x
Cutenox 302X
Clenox
Dilutol
Lupenox 20
Lupenox 60
Dripanina 040478
100
Relative Neutralization of Heparins by Heparinase - UV
25000
Mw (Da)
20000
15000
10000
5000
0
Heparin OP/253
(Porcine)
Heparin lot 15096
(Bovine)
Mw Sal
Heparin OP253
(Bovine)
Mw 0.125
Heparin lot 17046
Mw 0.25
Relative Neutralization of Heparins by Heparinase - RI
25000
Mw (Da)
20000
15000
10000
5000
0
Heparin OP/253
(Porcine)
Heparin lot 15096
(Bovine)
Heparin OP253
(Bovine)
Heparin lot 17046
Clotting time (sec)
Effect of Anhydromanno Content on the Anticoagulant
and Antiprotease Actions of LMWH
120
100
80
60
APTT
Heptest
40
0
10
20
30
% 1,6-anhydrosugar
40
% Inhibition
80
70
60
50
Anti-IIa
Anti-Xa
40
30
0
10
20
30
% 1,6-anhydrosugar
40
Differential Release of TFPI by Various
Generic Enoxaparins in Primates
300
Pre
Post
153%
250
TFPI (ng/ml)
95%
200
150
100
50
0
Lovenox
Cutenox
Clenox
Dilutol
Dripanina
Differential Generation of Nitric Oxide by
Various Generic Enoxaparins in Primates
40
Pre
Post
NO (µM)
30
20
10
0
Lovenox
Cutenox
Clenox
Dilutol
Dripanina
Effect of Lovenox and Generic Enoxaparins
in a Rabbit Stasis Thrombosis Model
IV
SC
2.0
120
*
*
1.5
80
+
60
40
ED50 (µg/kg)
ED50 (µg/kg)
100
+
1.0
0.5
20
0.0
0
Enoxaparin Cutenox
Clenox
Dilutol
Dripanina
Enoxaparin Cutenox
Clenox
Dilutol
Significant differences in the antithrombotic activities
of generic LMWHs were noted.
Dripanina
Effect of Intravenously Administered Generic LMWH
in a Jugular Vein Clamping Model of Thrombosis
Dose: 1 mg/kg IV
Circulation time: 30 min.
1.6
# of vein clampings
AXa U/ml
1.4
6
1.2
1.0
4
0.8
0.6
2
0.4
0.2
0
0.0
Enoxaparin Lupenox Cutenox Dripanina Dilutol
Clenox
Saline
Anti-Xa U/ml
# of vein clampings
8
Antithrombotic Effects of Various Generic LMWHs in a
Rat Laser-Induced Thrombosis Model
Dose: 1 mg/kg IV
Circulation time: 15 min.
3.0
# of Laser shots
AXa U/ml
2.5
# of Laser shots
8
2.0
6
1.5
4
1.0
2
0.5
0
0.0
Enoxaparin Lupenox Cutenox Dripanina Dilutol
Clenox
Saline
Anti-Xa U/ml
10
Comparative Bleeding Effects of Lovenox and Generic
Enoxaparins in a Rabbit Ear Blood Loss Model
8
Dose: 5 mg/kg
Circulation time: 15 min.
+
+
RBCs (10^9/L)
6
4
*
*
2
0
Saline Enoxaparin Cutenox
Clenox
Dilutol
Dripanina
Significant differences in the bleeding activities
of generic LMWHs were noted.
Pharmacodynamics of the Actions of Branded Enoxaparin
and Its Generic Versions in Primates
Dosage: 100 U/kg IV
Lovenox
Cutenox
Clenox
Lupenox
Dripanina
Dilutol
AXa (U/ml)
3
2
1
0
0
60
120
180
240
300
360
420
480
Time (min)
The apparent AUC of some of the LMWHs were markedly higher than the
limits for the generic drug acceptance
Pharmacodynamics of the Actions of Branded Enoxaparin
and Its Generic Versions in Primates
Dosage: 100 U/kg SC
Lovenox
Cutenox
Clenox
Lupenox
Dripanina
Dilutol
1.4
AXa (U/ml)
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0
180
360
540
720
900 1080 1260 1440
Time (min)
The apparent AUC of some of the LMWHs were markedly higher than the
limits for the generic drug acceptance
Pharmacodynamics of the Actions of Branded Enoxaparin
and Its Generic Versions in Primates
Dosage: 100 U/kg IV
200
Lovenox
Cutenox
Clenox
Lupenox
Dripanina
Dilutol
180
TFPI (ng/ml)
160
140
120
100
80
60
40
20
0
60
120
180
240
300
360
420
480
Time (min)
Burst release of TFPI markedly differed after bolus administration of enoxaparins.
Pharmacodynamics of the Actions of Branded Enoxaparin
and Its Generic Versions in Primates
Dosage: 100 U/kg SC
200
Lovenox
Cutenox
Clenox
Lupenox
Dripanina
Dilutol
TFPI (ng/ml)
180
160
140
120
100
80
60
40
0
180
360
540
720
900 1080 1260 1440
Time (min)
AUC for TFPI release markedly differed among generic products.
Pharmacodynamics of the Actions of Branded Enoxaparin
and Its Generic Versions in Primates
Dosage: 100 U/kg SC
1.0
TAFI (PEU/ml)
0.8
0.6
0.4
0.2
0.0
Lovenox Cutenox Clenox Lupenox Dripanina Dilutol
TAFI inhibition differed significantly among generic LMWHs.
Pharmacodynamic Differentiation of
Generic Versions of LMWHs
• Despite similar molecular weights and anti-Xa potencies,
pharmacodynamic differences in animal models were
evident between different generic LMWHs.
• The inhibition of TAFIa generation in normal human
plasma ranged from 42 to 63% and was not proportional
to the USP potency or anti-Xa activities of the generic
versions of enoxaparin.
• The ED50 for antithrombotic effects (IV) ranged from 62
– 91 µg/kg for generic versions compared to 72 µg/kg for
the branded product.
• The ED50 for antithrombotic effects (SC) ranged from
0.9 – 1.5 mg/kg for generic versions compared to 1.3
mg/kg for the branded product.
Pharmacodynamic Differentiation of
Generic Versions of LMWHs
• The generic LMWHs produced varying degrees of
antithrombotic activity in two rat models of thrombosis
that were not proportional to circulating anti-Xa levels.
• The relative hemorrhagic effects after a 5 mg/kg IV
dosage of different generic versions of enoxaparin
ranged from 2.9 to 5.6 x 10^9 RBC/L in comparison to
Lovenox which was 4.1 x 10^9 RBC/L.
• In primates, TFPI levels increased 95 to 153% following
administration of generic LMWHs (143% for Lovenox).
• In primates, NO levels increased 11 to 53% following
administration of generic LMWHs (56% for Lovenox).
Do Generic LMWHs Comply with FDA
Standards for Generic Approval?
• Mean difference in bioavailability cannot differ by
more than – 20% to + 25 % from innovator
product.
– The pharmacodynamic studies in both the IV and SC
regimens for the anti-Xa, anti-IIa and TFPI release
clearly show that some of the generic products do not
comply with the above rule.
– Similarly, the modulation of TAFI and thrombin
generation inhibition assays show marked differences
among generic LMWHs.
Generic LMW Heparins
Guideline Development
A.
Origin of the starting material (UFH or crude heparin) /
species specifications
B.
Manufacturing process / patent adherence
C.
Molecular and structural characterization
D.
Biophysical and biochemical profile
E.
Pharmacological profile
F.
a.
Animal models
b.
PK/PD in humans
Clinical validation of the efficacy and safety claim
EP, USP, US FDA, EMEA, WHO are debating these issues.
There are no clear guidelines at this time!
Unresolved Issues in the Development of
Generic Low Molecular Weight Heparins.
1.
Current guidelines for generic drugs are not valid for the
acceptance of generic LMWHs.
2.
LMWHs are complex multicomponent drugs requiring revised
guidelines for genericization.
3.
LMWHs are chemically modified complex natural
glycosaminoglycans with individual profiles.
4.
Bioassay specifications only require partial characterization
and are not valid for LMWHs.
5.
Xa and AIIa only represent partial pharmacological activities
and do not represent total pharmacodynamic profile.
6.
Pharmacokinetics of oligosaccharide components are
composition dependent.
7.
No requirements for raw material specifications.
Conclusions
• These studies suggest that the current regulatory
requirements in terms of anti-Xa potency specifications
and molecular weight profile may be inadequate as sole
acceptance criteria for generic LMWHs.
• Preliminary pharmacodynamic studies have identified
differences among currently available generic versions of
enoxaparin and underscore the importance of in vivo
equivalence studies to validate the biosimilarity of
generic versions of branded LMWHs.
• Guidelines for the acceptance of generic LMWHs may
include the effect of such agents on whole blood clotting
times, neutralization studies, platelet function assays,
TFPI release and/or animal models.
• Each of the generic products may have an individual
profile in a given indication. Therefore, a generic product
may not be given an umbrella approval for all clinical
indications and warrant validation in a given indication.