prof. alan cohen - iwgthalassemia.it - 17.pdf · alan cohen. serve on the dsmb for clinical trials...
TRANSCRIPT
PROF. ALAN COHEN
Serve on the DSMB for clinical trials for ApoPharma.
Consultant to Novartis
Scientific Advisor for Roche
Disclosures
• No one can discuss beta thalassemia in 20 minutes.
• I will address current status in (1) transfusion therapy, (2) assessing iron overload and (3) managing chelation therapy.
A DIFFICULT TASK
Sisyphys (1548-49) by Titian
• Optimal transfusion practices
• Assessment of iron overload
• Iron chelators
OUTLINE
Cazzola M, et al. Haematologica. 1997;37:135-40.Wolman IJ. Ann NY Acad Sci. 1964;119:736-47.
Transfusion programs in β-thalassemia major
Hypertransfusion (Hb > 9-10
g/dL) to relieve anemia and
decrease ineffective
erythropoiesis
Improved growth
Less organomegaly
Fewer fractures
Less facial deformity
Less impairment of
normal activity
• Old rule: if at all possible, see if you can get by without transfusion
• New rule: unless the disease is very mild or there is a major concernabout blood safety or availability, offer transfusion. The burden of proof is now on the withholding of transfusion
• New rule: Choose a pre-transfusion hemoglobin level (usually 9-10.5) based on the patient’s quality of life and suppression of ineffective
erythropoiesis
1. Taher AT, et al. Blood. 2010;115:1886-92.
A change in transfusion strategy for thalassemia
“Although current recommendations suggest initiating transfusion therapy after complications have manifested, it may be worthwhile considering earlier initiation as a
preventive approach.”1
• Confirmed diagnosis of severe anemia1
• Laboratory criteria1
• Hb < 7 g/dL on 2 occasions, > 2 weeks apart (excluding all other contributory causes, such as infections)
OR
• Laboratory and clinical criteria,1 including Hb > 7 g/dL with• facial changes• poor growth• impairment of activity• fractures• severe EMH
• All guidelines recommend that in addition to anemia, clinical symptoms and complications should be carefully monitored to determine the need for regular transfusions2
1. Trompeter S, Cohen A. In: Cappellini MD, et al. Guidelines for the management of transfusion dependent thalassaemia (TDT). 3rd ed. Nicosia, Cyprus: Thalassaemia International Federation; 2014. Available from: http://www.resonancehealth.com/images/files/clinician-information/patient-management-guidelines/TIF%20Guidelines
%20for%20the%20Management%20of%20Transfusion%20Dependent%20Thalassaemia.pdf. 2. Musallam KM, et al. Acta Haematol. 2013;130:64-73.
Whom to transfuse
Iron parameters and circulating non–transferrin-bound iron levels increase after transfusions of older RBCs in healthy volunteers.
©2011 by American Society of Hematology
Hod EA et al, Blood 2011
• Optimal transfusion practices• better understanding of the optimal hemoglobin level
• better understanding of storage effects on blood requirements
• pathogen inactivation
• blood substitutes
WHAT IS LEFT TO DO?
• Optimal transfusion practices
• Assessment of iron overload
• Iron chelators
OUTLINE
IRON BALANCE
15–30 mg/day
Desquamation
Blood loss
Stool loss
1–2 mg/day
1–2 mg/day
Transfusion
Diet
Urinary loss
Serum ferritin (SF)
– SF levels inconsistently reflect liver iron concentration (LIC)and poorly predict cardiac iron concentration1,2
– ferritin levels underestimate iron load in non-transfusedpatients
Cardiac and liver MRI3,4
– assessments of liver iron and cardiac iron by T2* and R2 arecalibrated and reproducible
– however, LIC may be a poor predictor of cardiac ironconcentration
KEY POINTS IN MONITORING
IRON OVERLOAD
1. Brittenham GM, et al. N Engl J Med. 1982;307:1671-5.
2. Karam LB, et al. Pediatr Blood Cancer. 2008;50:62-5.
3. St Pierre TG, et al. Blood. 2005;105:855-61.
4. Anderson LJ, et al. Eur Heart J. 2001;22:2171-9
• Assessment is not needed to decide to begin chelation therapy inyoung children. Just determine the cumulative RBC load and beginafter 10-20 transfusions.
• Assessment is needed to monitor organ iron function and managechelation therapy. Begin MRI measurements of liver and cardiac iron at
5-10 years of age.
When to assess for iron overload
Liver R2 images and distributions
Timothy G. St. Pierre et al. Blood 2005;105:855-861©2005 by American Society of Hematology
Kirk P, et al. J Cardiovasc Magn Reson. 2009;11 Suppl 1:O2.
Cardiac T2* predicts cardiac failure in β-thalassaemia major
> 10 ms0
0.10
0.20
0.30
0.40
0.50
0.60
0 30 60 90 120 150 180 210 240 270 300 330 360
Follow-up time (days)
Pro
po
rtio
n o
f p
atie
nts
wit
hh
ear
t fa
ilure
< 6 ms
6–8 ms
8–10 ms
Kaplan–Meier curve showing the proportion of patients who developed overt cardiac failure over a 12-month period according to their baseline cardiac T2* value if no
changes were made to their chelation regimen
World map showing the distribution of the prevalence of severe myocardial iron loading at first CMR scan.
John-Paul Carpenter et al. Haematologica 2013;98:1368-1374
©2013 by Ferrata Storti Foundation
• Assessment of iron overload• dissemination of available technology
WHAT IS LEFT TO DO?
• Optimal transfusion practices
• Assessment of iron overload
• Iron chelators
OUTLINE
Property Deferoxamine Deferiprone Deferasirox
Usual Dose
For TDT
25 – 50 mg/kg/day 75 – 99 mg/kg/day 20 – 40
mg/kg/day
14 – 28
mg/kg/day
Route SC or IV Oral tablet or oral
solution
Dispersible
tablet
Film-coated
tablet or
sprinkles
Dosing frequency Over 8 to 24 hours 3 times daily Once daily
Adverse Effects Local reactions
Audiologic
Ophthalmologic
Bone abnormalities
Pulmonary disease
Gastrointestinal
Neutropenia
Agranulocytosis
Arthralgia
Hepatic
Gastrointestinal
Hepatic
Renal
Rash
Availability Licensed worldwide
1st line agent
Licensed in Europe,
U.S. as 2nd line
Licensed in
Europe- 6y+
(2 - 5y as 2nd line)
U.S.- 2y+
Challenges Adherence with
parenteral
Weekly blood count
monitoring
GI side effects may limit
optimal dosing
Properties of Iron Chelators
Adapted from Kwiatkowski, Hematology, 2011
Iron locationDeferoxamine
(Desferal)
Deferiprone
(Ferriprox)
Deferasirox
(Exjade, Jadenu)
Liver +++ ++ +++
Heart ++* +++ ++
Endocrine + ++ +
Efficacy of Chelators:
Organ-Specific Iron Removal
*Enhanced with higher dose, continuous infusion
• When LIC is very elevated, consider a regimen containing DFX or DFO
• When cardiac T2* is low, consider a regimen containing DFP
• When cardiac dysfunction present, include intensive DFO
• For endocrinopathies, consider a regimen with DFP
• Organ-specific iron loading (cardiac, liver, endocrine)
• Ongoing transfusional iron intake (Cohen, Blood 2008;111:583)
• Higher iron intake requires higher chelator dosing
• If acceptable iron burden, dose chelator to balance ongoing iron intake
• Adherence (Trachtenberg, Am J Hem, 2011;86:433; Piga, Haematologica,
2003;88:489)
• Generally better with oral chelation
• No drug works if patient doesn’t take it
• Adverse effects• Some are dose-related
Adjusting Chelation: Factors to Consider
Improved Chelation RegimensCombination Therapy
• Additive patterns of iron excretion suggest chelation of different pools.
• Adjust ratio of chelators to maximize excretion while minimizing toxicity.
Kattamis et al, 2006
COMBINATION ORAL AND PARENTERALCHELATION THERAPY
DEFEROXAMINE AND
DEFERIPRONE
DEFEROXAMINE AND
DEFERASIROX
Lai et al, 2013
Ferritin
ng/mL
LIC
mg/g dw
Cardiac
T2* (ms)
LVEF
(%)
Baseline 581 ± 346 1.6 ± 1.1 34.1 ± 5.8 61 ± 6
12 –24 mo 103 ± 60 1.0 ± 0.2 36.9 ± 5.6 65 ± 7.6
p-value 0.0001 0.0019 0.0012 0.0014
N = 16; mean age 35 ± 7.5 years
Deferiprone (75 - 100 mg/kg/day)
Deferasirox (20 – 25 mg/kg/day)
• Reversal of cardiac dysfunction
in 2/4 patients
• Improvement in 2h glucose in
2/8 with impaired glucose
tolerance
Farmaki, Blood Cells, Mol, Dis, 2011;47:33
COMBINATION ORAL CHELATION IN THALASSEMIA:
DEFERIPRONE AND DEFERASIROX
Adherence to treatment with different chelation therapies
• Adherence was assessed in 120 patients
• A statistically significant difference was noted among the 3 groups (P<0.001)
Forget their
treatmentAlways adhere
Pa
tie
nts
(%
)
Adherence
Deferoxamine (n=33)
Deferasirox (n=70)
Deferoxamine + deferiprone (n=17)
Goulas V et al. ISRN Hematol 2012;2012:139862.
0
10
20
30
40
50
60
• Iron chelators• Improving adherence
• increasing experience with combination therapy
• resolution of optimal chelation goal
WHAT IS LEFT TO DO?
HAVE WE CHANGED THE
PROGNOSIS IN THALASSEMIA?
Survival by Cohort of Birth (N=977)Su
rviv
al P
rob
abili
ty
Age (Yr)0 5 10 15 20 25 30
0.00
0.25
0.50
0.75
1.00
60 - 64
65 - 69
70 - 74
75 - 7980 - 84
85 - 97
P<0.00005
Borgna-Pignatti et al, 2004
Decline in Cardiac Mortality Over 10 Years at Thalassemia Unit Cagliari
Death Rate
(Per 1000
Patient-years)
1998-2000
0
p = 0.012 p = 0.014
8
10
14
12
6
4
2
2001-2003 2004-2006 2007-2009 2010
Modell et al: J Cardiovasc Magn Reson, 2008
Comparison of life expectancy for patients alive at the beginning of 1970, 1980, 1990 and 2000. The calculation shows an average life-expectancy of 17 years in 1970, 27 years in 1980 and 37 years in 1990. Since 2000 over 80% of patients have a life expectancy of more than 40 years. It is still not possible to estimate ultimate life-expectancy, and the prognosis for older patients remains "open-ended".
CHANGING LIFE EXPECTANCY IN THALASSEMIA MAJOR
KAPLAN-MEYER ANALYSIS OF THE SURVIVAL OF 257
PATIENTS WITH TRANSFUSION DEPENDENT THALASSEMIA
V.Gabutti & A.Piga, Acta Haematol 1996; 95:26-36
YEARS
CU
MU
LA
TIV
E P
ER
CE
NT
SU
RV
IVA
L
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
well chelated=149
badly chelated=108