High expression of Cereblon (CRBN) is associated with improved clinical response
in patients with Multiple Myeloma treated with Lenalidomide and Dexamethasone
Daniel Heintel1, Arnold Bolomsky1, Martin Schreder1, Sabine Pfeifer1, Niklas Zojer1, Ulrich Jäger2, Heinz Ludwig1
1First Department of Medicine, Center for Oncology and Hematology, Wilhelminenspital, Vienna, Austria; 2Department of Internal Medicine I, Division of Hematology, Medical University of Vienna, Austria
Analysis of different cell compartments showed low CRBN in normal BM (N=8) and
Figure 2A and B. Clinical response according to CRBN expression in patients treated
Background
CD138- BM cells (N=6), but high CRBN in corresponding CD138+ sorted cells (N=6)
with lenalidomide/dexamethasone (N=27).
(Figure 1A). CRBN was detected in all 44 unsorted multiple myeloma samples
Immunomodulatory drugs (IMiDs) are highly active in the treatment of multiple myeloma
(Figure 1B). The median CRBN expression was 3.54 (range: 0.31-462.08) in newly
100
Results
(MM), but the mechanisms of action are still incompletely understood. Recently, Cereblon
diagnosed patients, and 4.39 (range: 0.90-16.23) in pre-treated patients.
100
(CRBN) has been identified as the primary target of thalidomide teratogenicity (Ito K et al,
Lenalidomide-based therapy resulted in CR in 3 (8%), nCR in 2 (5%), VGPR in 4
2010) and, moreover, as an essential requirement for response to IMiD therapy (Zhu YX et
(11%), PR in 17 (46%), and in MR in 4 patients (11%), respectively. Three patients
10
10
al, 2011). We aimed to evaluate whether expression levels of CRBN correlate with
(8%) had SD, and 4 (11%) had PD. Median CRBN expression was three times higher
pression
response to lenalidomide.
in responding (MR) patients compared to non-responders (3.65 vs. 0.99, p<0.01). In
1
ex
1
addition, a significant correlation between quality of response and CRBN expression
Patients and Methods
(r=0.34) was observed. This correlation remained statistically significant after
0,1
mRNA
0,1
exclusion of previously treated patients (r=0.37, p=0.02).
r=0.57
p=0.0004
r=0.61
p=0.0003
CRBN mRNA expression was measured by real time PCR in bone marrow (BM) samples
0,01
CRBN
Table 1. Quality of response and CRBN levels in patients treated with Len/Dex
0,01
of 44 well characterized MM patients treated with lenalidomide containing regimens. The
median age of patients was 65 years (range: 37-85 years). Nine patients had ISS-stage I, 9
0,001
0,001
stage II, and 26 had stage III. All patients, except 12, were newly diagnosed. None of the
Quality of
N
Median
range
CR-VGPR
PR-PD
CR-MR
SD, PD
patients had been exposed to lenalidomide before study entry. Full data documentation for
response
CRBN
N=7
N=20
N=23
N=4
response evaluation (> 2 cycles) was available in 37 patients (84%). Twenty-seven of
expression
these patients received lenalidomide/dexamethasone, 9 were treated with MPR, and 1
CR
3
7.26
5.88-9.89
patient received lenalidomide/bendamustine/dexamethasone. Responses were assessed
nCR
2
4.82
3.74-5.89
Figure 3. Correlation of CRBN with IRF4
Table 2. Correlation of CRBN with selected
according the International Myeloma Working Group criteria with the addition of near
expression in MM patients (N=44).
plasma cell differentiation factors
VGPR
2
18.47
8.20-28.74
complete response (nCR), and minimal response (MR).
PR
13
3.02
1.15-6.70
10000
Results
1000
MR
3
6.74
3.65-462.08
100
SD
1
0.74
-
rp
Normal BM of 8 donors was used as a reference. CRBN expression in these cells was
10
PD
3
0.90
0.30-1.087
F4
XBP1
0.69
0.00004
arbitrarily set as 1. In the 8 myeloma cell lines (U266, KMS-12-BM, OPM-2, NCI-H929,
1
IR
MM.1S, SK-MM-1, RPMI8226) tested a higher CRBN expression level compared to normal
BLIMP
0.26
0.1
0,1
BM was found. (range: 2.34­10.32). CRBN expression levels showed an almost linear
When the analysis was restricted to 27 patients uniformly treated with lenalidomide
0,01
PAX5
-0.01
0.5
correlation between sorted and corresponding unsorted BM cells (r= 0.97, p= 0.0008).
r=0.58
p=0.00007
and dexamethasone, an even more pronounced association between myeloma
Based on these findings, unsorted samples were used instead of sorted cells for further
0,001
response and CRBN expression was noted. Median CRBN expression was lower in
0,001
0,01
0,1
1
10
100
analysis. In unsorted samples, no correlation was found between the degree of plasma cell
patients with SD and PD than in normal BM. In contrast in patients with CR, nCR,
CRBN
BM infiltration and CRBN expression levels.
VGPR, PR or MR, a higher CRBN expression compared to normal BM was found
(Table 2). Of note, the lowest CRBN was found in 4 non-responsive patients (SD, PD)
Figure 1A. CRBN expression in
Figure1B. CRBN expression levels in
suggesting that CRBN is required for anti-myeloma activity. CRBN expression was
Conclusions
MMCD134- and CD138+ sorted cells
44 MM patients
significantly higher in patients with greater tumor response: VGPR vs. PR-PD
1000
6
(p=0.0004) (Figure 2A); MR vs. SD, PD (p=0.0003) (Figure 2B). This correlation
CRBN expression correlated significantly with response to lenalidomide based treatment
remained statistically significant after exclusion of previously treated patients.
5
100
Univariate analysis between established prognostic factors such as beta-2-
CRBN expression likely is an important predictor for response to lenalidomide therapy.
pression
4
microglobulin, albumin, ISS stage, hemoglobin, FISH defined cytogenetic aberrations,
ex
CRBN expression is closely associated with IRF4, which is an important target of IMiD
10
and response revealed no significant correlation. After a median follow up time of 32
3
therapy.
months (range: 7­89 months), 11 patients have died. CRBN expression did neither
mRNA 2
correlate with OS, but correlated closely with IRF4, an important transcription factor
Confirmation of these findings in large prospective trials would, for the first time, enable
1
1
required for myeloma survival (r=0.58; p<0.00007). (Figure 3). The correlation
individualized decisions of lenalidomide (and possibly thalidomide) therapy in patients
CRBN
between CRBN and IFRF4 was also noted in CD138+ sorted primary myeloma cells
with multiple myeloma.
(r=0.79; p=0.03; N=6).
Normal
CD138-
CD138+
BM samples (N=44)
BM (N=8)
(N=6)
(N=6)
Disclosures: DH, AB, MS, SP, NZ, HL: There are no relevant conflicts of interests to disclose; UJ: Roche, Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees and Research Funding; Mundipharma, AMGEN: Honoraria and
Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria and Research Funding; Biogen: Research Funding
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