Personalized hemophilia treatment
Abdulkareem Almomen, MD, FRCPC, Professor of Medicine-Hematology,
King Saud University & Blood and Cancer Center, Riyadh
Jeddah, 24 February 2018
CONFIDENTIAL; DO NOT DISTRIBUTE
Evolution of Hemophilia Therapies:
CONFIDENTIAL; DO NOT DISTRIBUTE
Nonfactor replacement therapies for hemophilia
Anti-tissue factor pathway inhibitor [Anti-TFPI]; OW/SC
RNA interference agent against antithrombin; OW/SC
Gene Therapy
Gene therapy has the potential to lessen disease severity from a severe phenotype to a moderate or mild phenotype through continuous production of factor VIII or IX after one administration of a gene vector, especially since a small rise in circulating coagulant proteins to at least 1% of normal levels can substantially ameliorate the bleeding phenotype.
Future Therapies
3
Peyvandi F, Garagiola I, Young G. The past and future of haemophilia: diagnosis, treatments, and its complications. Lancet. 2016;388(10040):187-197
Anti-tissue factor pathway inhibitor [Anti-TFPI];
Anti-tissue factor pathway inhibitor [Anti-TFPI];
RNA interference agent against antithrombin
Gene Therapy
Gene therapy has the potential to lessen disease severity from a severe phenotype to a moderate or mild phenotype through continuous production of factor VIII or IX after one administration of a gene vector, especially since a small rise in circulating coagulant proteins to at least 1% of normal levels can substantially ameliorate the bleeding phenotype.
What Is Gene Therapy?
Gene therapy is1-2:
A strategy used to replace or repair a dysfunctional gene
Most applicable to diseases caused by a single gene mutation
An approach to improve symptoms or potentially cure a disease
Administered ex vivo or in vivo, depending on the vector
The vector (vehicle based on the capsid of a nonreplicating virus) delivers the desired gene to a particular target3
1. Kumar SR, et al. Mol Ther Methods Clin Dev. 2016;3:16034. 2. Thomas CE, et al. Nat Rev Genet. 2003;4(5):346-358. 3. Mingozzi F, et al. Blood. 2013;122(1):23-36.
Gene Therapy
Gene delivery vehicle or carrier
Gene that works
Cell
Nucleus
Added Gene
Genetic Material (Chromosomes)
Gene therapy aims to give a gene that works correctly to a person who needs it.
Gene Therapy
A cell contains genetic material within its nucleus made up of genes in chromosomes
These genes provide instructions to the cell and help it make proteins (like clotting factor)
When genes are missing or incorrect, it is difficult for the cell to work correctly
Cell
Nucleus
Genetic Material (Chromosomes)
Background
Proper factor VIII dosage requirement for hemophilia patients varies significantly due multifactorial influence including individual pharmacokinetics (PK), age, blood group, gender, type of factor used and type of test.
Therefore PK has to be performed for each patient according to each clotting factor and has to be repeated at certain intervals
Population based PK model (cannot be )
FVIII clearance obtained from 100 (10-65 y, 10 samples) and 52 children (1-5 y, 4 samples)
Effect of blood groups on FVIII& VWF O vs non- O (A,B,AB)
0
20
40
60
80
100
120
Group o Group A,B,AB
FVIII:C VWF:Ag
Effect of age on FVIII:C
Effect of age on VWF: Ag
Effect of age on ADAMTS13
Effect of age on: FVIII:C, VWF: Ag, VWF:CBA, VWF:Rcof, and ADAMTS13
0%
20%
40%
60%
80%
100%
120%
140%
160%
Age 50 y
FVIII:C VWF:Ag ADAMTS13
Effect of age on clearance and T1/2 of FVIII
Effect of age on clearance and T1/2 of FVIII
0
2
4
6
8
10
12
14
16
FVIII T1/2 (H)1 5 10 20 30 40 50 60 70
Effect of weight & BMI on in-vivo recovery of FVIII
Variation of FVIII T (H)
0
2
4
6
8
10
12
14
16
18
20
FVIII T 1/2 (h)
FVIII pd (14)
R.FIII(16)
BDD FVIII (11)
EHL FVIII (19)
Data are from different studies with different patients cohorts
Pharmacokinetic blood sampling
Adults:(11 samples) at zero, 15 min, 30 min, 1 hour, 3, 6, 9 hours, 24, 28, 32 hours, 48 hours
Children: (5 samples) 30 min., 1, 9 hours, 24 hours, 48 hours
New Methods !!!
New methods with less (2) blood samples
Many methods are being developed as a software that requires only 2 blood samples within 48 hours after infusion.
Each method is specific for each product
Variation of FIX T (H)
0
10
20
30
40
50
60
70
80
90
100
FIX T1/2 (H)
pdFIX (16.5)
r.FIX (17.5)
EHL.FIX (86)
Data are from different studies with different patients cohorts
Frequency Impact?
EHLs every 7-10 days
SHLs once weekly data
!!!
Effect of laboratory tests
Pre-analytical,
Test performance,
Type of test : PTT or chromogenic
Specific tests
In summary
Factor VIII & IX recovery, clearance and half-life are influenced by many factors including blood group, age, body weight, ethnicity, type of factor and type of testing.
Population model PK is not suitable for individual patients,
PK has to be performed for each patient individually, for each clotting factor concentrate and to be repeated at least once every 10 years, so that, adequate, cost effective dose and frequency can be calculated accurately for each patient
