Copeptin in Acute Myocardial
Infarction –
Background & Clinical Data
June 2010
Vasopressin & Copeptin - FAQs

What is Vasopressin (Copeptin) and where does it come from?

What is the physiological role of Vasopressin?

Why not simply measure Vasopressin?

Is Copeptin produced together with Vasopressin? Do both
analytes show the same kinetics?

Which Copeptin levels should be expected in Normals?

What may clinicians ask when you talk about Copeptin
(Vasopressin)?

What about the performance of the Copeptin KRYPTOR assay?

Copeptin in early rule out of myocardial infarction
 What is Vasopressin
(Copeptin) and where
does it come from?
Structure of Vasopressin
O
O
NH2
-C
NH2
NH2-
Arginine-Vasopressin (AVP)
 synonym: Vasopressin or antidiuretic hormone (ADH)
 peptide hormone
 9 amino acids
 Disulfide bridge between two cysteine amino acids
 C-terminal amidation
Synthesis of Vasopressin
 Synthesis as a precursor hormone
(pre-pro-vasopressin) in the hypothalamus
 Cleavage and transport in granules
down the axons
 Storage in granules in the posterior pituitary
 Release into nearby capillaries upon
appropriate stimulation
Figures adapted from: Golenhofen, Basislehrbuch Physiologie, Urban & Fischer; and Morgenthaler NG et al.: Clin Chem 2006
Information: Russel IC and Glover PJ: Critical Care and Resuscitation 2002; Ranger GS: IJCP 2002; Oghlakian G and Klapholz M: Cardiology in Review 2009
 What is the
physiological role of
Vasopressin?
Vasopressin - physiological role
Main role:
Regulation of water balance
- Increased plasma osmolality
- Decreased arterial circulating volume
AVP:
Synthesis in the
Hypothalamus
AVP:
acts via V2-receptors
in the kidney
-> water retention
Figure adapted from: Knoers NV N Engl J Med. 2005 May 5;352(18):1847-50
Vasopressin (AVP) effects
receptor location
effect
V2
kidney
water retention
V1a
vascular smooth
muscle cells
strong vasoconstriction
V1b
endocrine cells
(e.g. pituitary)
regulation of ACTH
secretion during stress
Effects of AVP dependent on concentration :
 maximal antidiuretic effect: below 15 pg/ml
 vasoconstrictor effect at higher concentrations
 very little effect on blood pressure at physiological levels!
Singh Ranger G, Int J Clin Pract 2002; 56(10):777-782
Vasopressin in stress situation
Myocardial infarction
STRESS
AVP
ACTH
Cortisol
 Why not simply measure
Vasopressin?
Quantification of Vasopressin is difficult
Protease
Vasopressin
Vasopressin
Receptor
Vasopressin
Vasopressin
Platelets
Further problem: very unstable ex vivo (even frozen)
Only specialized labs measure AVP (time to results several days)
Not a single FDA approved AVP assay on the market
LIMITED CLINICAL USE
Prohormone processing and assay
Signal
Vasopressin
Neurophysin II
Copeptin
Neurophysin II
Copeptin
Signal Peptidase
Vasopressin
Prohormone
Convertase
Vasopressin
Neurophysin II
Copeptin
Copeptin very
stable ex vivo
Fast assay (KRYPTOR)
Morgenthaler NG et al., Clin Chem. 2006
 Is Copeptin produced together
with Vasopressin?
 Show both analytes the same
kinetics in vivo?
LIA Assay
Correlation of Vasopressin and Copeptin
Morgenthaler NG et al., Clin Chem. 2006 Jan;52(1):112-9.
r = 0.78
Jochberger S et al., Schock 2009 31: 132-138
Validation in: Jochberger S et al., Intensive Care Med 2009 35:489-497
Copeptin – like Vasopressin – is rapidly degraded in vivo
Copeptin (pmol/L)
97.5 % percentile KRYPTOR:
17.4 pmol/L
Copeptin male 45 y, BMI 23
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
700
water
Copeptin female 23 y, BMI 19
food
800
900
t1/2: few minutes
1000 1100 1200 1300 1400 1500 1600 1700 1800
day time (hours)
Morgenthaler et al. Clin Chem 2006
 Which Copeptin levels should
be expected in Normals?
Copeptin is not age-related
Normal distribution
Morgenthaler NG et al., Clin Chem. 2006 Jan;52(1):112-9
Copeptin levels dependent on gender
Significantly higher levels in males
706 healthy volunteers
Bhandari SS et al, Clinical Science (2009) 116, 257–263
Copeptin: Influence of exercise
97.5 % pecentile KRYPTOR:
17.4 pmol/L
Morgenthaler NG et al., Clin Chem. 2006 Jan;52(1):112-9
 What may clinicians ask
when you talk about
Vasopressin / Copeptin?
disturbed Vasopressin /
Copeptin secretion and
water / salt balance?
Diagnosis of diabetes insipidus
38 patients (33 after transphenoidal surgery, 5 without surgery)
n = 29 normal posterior pituitary function
n = 9 diabetes insipidus centralis
insulin-induced hypoglycemia test
25
20
p = 0.003
15
10
5
0
intact post. pituitary
Diabetes insipidus
Basal Copeptin
Copeptin (pmol/L)
Copeptin (pmol/L)
25
p < 0.001
20
15
10
5
0
intact post. pituitary
Diabetes insipidus
 Glucose < 2 mmol/l
Katan et al. JCEM 2007
Diagnosis of diabetes insipidus
100% sensitivity – 100% specificity
Copetin level < 4.75 pmol/L
Katan et al. JCEM 2007
Diagnosis of diabetes insipidus
Diabetes Insipidus is no
indication for the
KRYPTOR Assay!
FAS Kryptor
Copeptin (pmol/L)
25
p < 0.001
20
15
10
5
0
intact post. pituitary
Diabetes insipidus
Katan et al. JCEM 2007
Hyponatremia
 most common fluid and electrolyte disturbance
 prevalence: 15-30% of hospitalized patients
 variety of disorders causing hyponatremia - treatment varies widely
Fenske et al.: J Clin Endocrinol Metab, 2009
Assay Performance
 What about the performance of
the KRYPTOR assay?
Copeptin assay parameters
Sample type
serum, plasma (EDTA and heparin)
Volume
50 µl
Incubation time
19 min
Stability at RT
min. 8 hours
Freezing and thawing
no influence up to 3 cycles
LOD (limit of detection)
4.8 pmol/L
FAS (20% CV)
12 pmol/L
Direct measuring range
4.8 to 500 pmol/L
Measuring range with automatic dilution
4.8 to 1200 pmol/L
Data taken from IFU (instructions for use)
Assay Performance
 Copeptin in early rule out
of myocardial infarction
Background
 Chest pain patients about 10% of ED consultations
 Cardiac Troponin current diagnostic gold standard
 Troponin retesting after 6-8 hours necessary
due to delayed increase
 Rapid and reliable rule out of acute MI already at
presentation is a large unmet clinical need
Hypothesis
Combination of
Cardiac Necrosis
Troponin
+
Endogenous Stress
Copeptin
rapid and accurate rule out of AMI
• at initial presentation
• without Tn retesting after 6 to 8 hours
Proof of concept study
Methods
 Consecutive pts with chest pain <12h
 Observational study
 Serial blood sampling: 0h,1h, 2h, 3h, 6h
 Follow up 90d, 360d, 720d
 Adjudicated Diagnosis:
– 2 independent experts
– using all clinical information within 60d FU
(History, physical examination, ECG, cTn, chest x-ray,
echo, coronary angiography, exercise testing (MPS),
CT-scans, endoscopy, ....)
– Blinded for investigational biomarkers
Adjudicated final diagnoses
Chest pain of
unknown origin
(9%)
Myocardial Infarction (17%)
Thereof
STEMI (37%)
NSTEMI (63%)
Unstable Angina
(16%)
Non-cardiac
chest pain (46%)
Non-coronary cardiac
chest pain (13%)
Copeptin levels at presentation
Reichlin et al. J Am Coll Cardiol 2009;54:60-8
Copeptin and Troponin levels at presentation
Reichlin et al. J Am Coll Cardiol 2009;54:60-8
ROC curves at presentation
Reichlin et al. J Am Coll Cardiol 2009;54:60-8
Rapid rule out of AMI at presentation
314 = 65% (cTnT / Copeptin negative)
487 pts
173 = 35% (cTnT / Copeptin positive)
Reichlin et al. J Am Coll Cardiol 2009;54:60-8
Conclusion
1. Copeptin significantly improves the early diagnosis of AMI
(AUC for combination with Troponin T 0.97).
2. The combination of Copeptin and Troponin T allows a rule
out of AMI at presentation with a sensitivity of 98.8% and a
NPV of 99.7%.
3. The use of Copeptin in conjunction with Troponin T, ECG
and clinical findings may obviate the need for prolonged
stay in the ED and Troponin retesting after 6 to 8 hours in
two-thirds of patients. This change in clinical practice might
result in significant medical and economic benefits.
Validation study
•
Paper submitted, confidential Data
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Methods

1386 patients with suspected acute coronary syndrome

Multicenter approach

Troponin T (4th generation Roche Diagnostics) used for
Gold Standard Diagnosis

Diagnosis NSTEMI:
- one value above 0.03 ng/mL !
- and a typical kinetic (rise or fall of at least 20%)
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Baseline characteristics
 + 289
 + 211
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Final diagnosis
7%
15%
13%
65%
Potential „rule out-portion“: ca. 78%
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Time course of different markers
Patients with time
of chest pain
onset < 2h
MI: n=75
NCCP: n=213
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Diagnostic performance of Copeptin/Troponin T
AUCs according to time of chest pain onset
Troponin T
Copeptin
< 3h
< 6h
< 12h
All
0.77
0.8
0.81
0.84
0.79
0.78
Paper in preparation for submission, confidential Data
0.78
0.74
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Diagnostic performance (1)
T=0
Copeptin + Troponin T
Best AUC
combination
Copeptin / Troponin T
0.93
TnT+ Myo: 0.91
TnT + CKMB: 0.88
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Diagnostic performance (2)
Troponin T
Copeptin
Combination
(cut-off:
0.03 ng/mL)
(cut-off:
13 pmol/L)
Sensitivity
62
58
88
Specificity
97
78
76
Positive predictive value
87
46
55
Negative predictive value
89
85
95
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Copeptin and sensitive Troponin
*TnI > 0.04 ng/ml
*Copeptin cut-off 9.8 pmol/l
† Copeptin cut-off 13 pmol/l
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.
Conclusion
Keller et al. J Am Coll Cardiol 2010;55:2096-2106.