Download A Novel, High Sensitivity Marker, hsPro

2
A Novel, High Sensitivity Marker, hsPro-C2, Of Cartilage Formation, Was
Developed And Tested In A Phase II Clinical Trial Of PTH
3
4
Yunyun Luo1, Yi He1, Inger Byrjalsen1, Kim Henriksen1, Natasja Stæhr Gudmann1, Ali Mobasheri2, Gitte
Hansen1, Morten A. Karsdal1, Anne C. Bay-Jensen1
5
1
6
2
1
7
8
9
Nordic Bioscience A/S, Herlev, Denmark
D-BOARD EU Consortium for Biomarker Discovery, University of Surrey, Surrey, United Kingdom
Purpose:
10
11
12
13
14
15
16
17
18
19
Presently, measurement of cartilage formation relies on magnetic resonance imaging (MRI), which is a
sensitive measure, but which need long follow-up time. Thus, there is an unmet need, in disease-modifying
osteoarthritis drug (DMOAD) development, for an objective and non-invasive marker of cartilage formation,
which can provide early indication of drug efficacy. The objective was to enable assessment of type IIB
collagen synthesis in serum from human subjects. Such tool may be applicable as a non-invasive biomarker
of cartilage repair and growth in the development of cartilage anabolic drugs. No cartilage anabolic DMOAD
have to date been approved thus for proof of concept, we used an osteoporosis (OP) trial testing teriparatide
(human parathyroid hormone (PTH) 1-34). Teriparatide has been shown to have potential chondroprotective and chondro-regenerative effects on articular cartilage in vitro and in vivo. However, it remains
unclear whether the pro-anabolic effect of teriparatide translate to human OA.
20
Methods:
21
22
23
24
25
26
27
28
29
A high sensitivity competitive electro-chemiluminescence immunoassay for detection of PIIBNP (hsPro-C2
ECLIA) was developed and the technical performance evaluated. From a randomized, double-blind placebocontrolled study with an open-label active comparator/positive control (teriparatide) in postmenopausal
women with OP (clinicaltrials.gov: NCT01321723), the biomarker sub-study included 64 Caucasian
postmenopausal women (age 45-80 years) with OP duration of at least 5 years. Thirty-two women were
treated with teriparatide, and 32 with placebo. Biomarkers of bone formation (PINP; procollagen type I Nterminal propeptide) and cartilage formation (hsPro-C2) were analyzed retrospectively at baseline, week 4,
12 and 24. Correlation between PINP and hsPro-C2 at baseline and change at week 4 relative to baseline
were investigated by Pearson’s correlation.
30
Results:
31
32
33
The technical performance of hsPro-C2 ECLIA was summarized in Table 1. The intra-assay CV was 5.4% and
the inter-assay CV was 5.5%. The measurement range was 1-32 ng/ml. The spiking and dilution recovery
tested in human serum were 100 ± 20% within the measurement rang of the assay.
34
35
The median percent change in serum hsPro-C2 level was higher in teriparatide treated group compared to
the placebo group at week 4 (9%), 12 (3%) and 24 (10%), although it was not statistically significant (Figure
36
37
38
1A). Furthermore, elevated bone formation was significantly associated with the change of marker in
cartilage formation at week 4 and 24 (r = 0.7143, P < 0.0001; r = 0. 4005, P < 0.05). This was not observed in
the placebo group (data not shown).
39
Conclusions:
40
41
42
43
44
In spite of the small sample size of this study there was a clear trend toward increased cartilage formation in
the PTH treated group over time. Furthermore, hsPro-C2 changes correlated with the changes in PINP, which
is believed to be a pharmacodynamics biomarker of teriparatide treatment, indicating that hsPro-C2 reflect
a possible chondro-anabolic effect of PTH. It is concluded that hsPro-C2 may be a promising and novel marker
of cartilage formation to be used in DMOAD development.
45
Table 1 Summary of technical performance for two biomarkers assays
Parameters
Linear range of standard (ng/mL)
LLOD (ng/ml)
Intra-assay % CV
Inter-assay % CV
Spiking Recovery, % range
Dilution Recovery, % range
46
hsPro-C2 Competition ECLIA
PINP Sandwiches ECLIA
1.0 - 38.5
0.13
5.4
5.5
98
99
5-1200
<5
2.2
2.8
NA
NA
LLOD: lower limit of detection
47
48
49
50
51
52
53
54
55
56
57
Figure 1 Response as median percent change from baseline (± interquartile range) in hsPro-C2 (A) and PINP (B) in women receiving
teriparatide (●) or placebo (○). Teriparatide was administered subcutaneously with 20 mg/day. The marker of cartilage formation
(hsPro-C2; procollagen type IIB N-terminal propeptides), and marker of bone formation (PINP; procollagen type I N-terminal
propeptides) were measured with regular intervals throughout the study period. The responses in teriparatide treated and placebo
groups are plotted as the median percent change of individual baselines. The % change of Pro-C2 values between teriparatide treated
and placebo groups were compared with a two-way ANOVA test. Asterisks indicate the following: *P < 0.05, **P < 0.01, ****P <
0.0001.
58
59
60
Table 2. Associations between biomarkers of bone formation and cartilage formation percent changes relative to baseline in
teriparatide treated group. Pearson’s correlation coefficient (r) are indicated.
63
Log (hsPro-C2_pct),
week 4
Log (hsPro-C2_pct),
week 12
r
P value
r
0.7143
Log (PINP_pct), week 4
P value
< 0.0001
r
0.3404
Log (PINP_pct), week 12
P value
0.0708
r
Log (PINP_pct), week 24
P value
PINP, amino terminal propeptide of type I procollagen; pct: percent change relative to baseline
Log (PINP), baseline
61
62
Log (hsPro-C2),
baseline
-0.0528
0.6786
Log (hsPro-C2_pct),
week 24
0.4005
< 0.05