Written in Blood
PERSPECTIVES
“When considering the clinical application
of MRD in any disease, there are multiple
levels to the story: The first is whether
MRD can predict post-treatment out-
comes; the second is determining what
method is best; and the third – and
most important and most difficult
hurdle to clear – centers on intervening
to modify risk and change the course of
disease in patients at the greatest risk
of relapse.
This particular study looked at the
role MRD plays in AML. There are many
methods to detect MRD in AML, includ-
ing metaphase cytogenetics, fluores-
cence in situ hybridization, multicolor
flow cytometry, and molecular analyses
(e.g., next-generation sequencing) for
known mutations. Each of these meth-
ods has advantages and drawbacks, but
most hinge on identifying aberrations
that set the leukemia cells apart from
normal myeloblasts. So far, NPM1 mu-
tations have been identified as an ideal
candidate marker for MRD, but these
are present in approximately 35 percent
of cases of newly diagnosed AML.
This study used NGS to detect MRD
in patients undergoing alloHCT. The key
here is that the samples were paired,
meaning that each patient had a
sample from the time of diagnosis and
at the time of MRD assessment.
The innovative portion of this study
is the group’s use of bioinformatics. To
improve the performance of mutation
detection by NGS, the authors used an
error-corrected sequencing approach to
identify small amounts of MRD and dif-
ferentiate that from sequencing errors.
Using this method, they were able to
conduct reliable MRD assessment on a
wide swath of AML patients.
While this is certainly a step for-
ward, there are several unanswered
questions. Mutation detection for
MRD assessment is hampered by the
presence of clonal hematopoiesis and
ancestral clones. These not only pre-
dispose a patient to the development
of AML but also can be present at the
time of MRD assessment and influence
the interpretation of this testing in a
multifaceted manner. Ultimately, as
our detection of MRD in AML is refined,
future studies must turn to interven-
tions that will reduce the risk of relapse
and improve the outcomes for our
patients.”
Aaron T. Gerds, MD, MS
Assistant Professor in Medicine
Cleveland Clinic Taussig Cancer Institute
Cleveland, OH
36
ASH Clinical News
Next-Generation Sequencing MRD Assessment Valuable Tool
in AML Management
Assessing minimal residual disease (MRD)
using next-generation sequencing (NGS)
in patients with acute myeloid leukemia
(AML) prior to undergoing allogeneic he-
matopoietic cell transplantation (alloHCT)
was highly predictive of post-transplant
relapse and survival. This technique could
help identify patients who should undergo
alloHCT, according to Felicitas Thol,
MD, from the department of hematology,
hemostasis, oncology, and stem cell trans-
plantation at Hannover Medical School in
Germany, and researchers.
“Patients with intermediate-risk AML
[may be] transplanted if they are in first
complete remission,” study coauthor Michael
Heuser, MD, also from the Hannover Medi-
cal School, told ASH Clinical News. “Our
diagnostic approach identifies patients with
AML who have an excellent prognosis with
alloHCT and a low risk of relapse, which
may help better select those patients who
would benefit most from transplant.”
The study included 116 adult patients
with AML who were in complete remission
(CR) and underwent an alloHCT between
1996 and 2016. Patients also had an available
DNA sample at the time of diagnosis and
during CR prior to undergoing alloHCT.
To validate the prognostic effect of NGS-
based MRD assessment, the researchers first
evaluated MRD at diagnosis, in remission,
and at molecular relapse in four patients
with NPM1-mutated AML using an estab-
lished polymerase chain reaction testing
method and the NGS method to establish
concordance between the two methods.
Investigators collected and quantified
MRD using a 46-gene sequencing panel in
samples from bone marrow and periph-
eral blood. Of the entire cohort of 116 pa-
tients, 20 were excluded because they did
not have any appropriate mutation in the
myeloid panel analysis or the variant allele
frequency was >5 percent in the selected
Results From Univariate and Multivariate Analyses
(MRD Positive vs. MRD Negative)
TABLE 1.
Univariate analysis
Multivariate analysis
Hazard ratio 95% CI p Value Hazard ratio 95% CI p Value
Cumulative incidence
of relapse 5.58 2.47-12.59 <0.001 5.67 2.30-14.0 <0.001
Relapse-free survival 3.56 1.86-6.81 <0.001 3.41 1.72-6.75 0.001
Overall survival 3.06 1.54-6.12 0.002 3.00 1.41-6.38 0.004
MRD mutation before alloHCT.
Ninety-six patients were evaluable for the
main analysis: 43 patients (45%) were MRD
positive and 53 (55%) were MRD negative
prior to transplant. Patients who were MRD
positive more often had an adverse cytoge-
netic profile and complex karyotype, the au-
thors noted, and, “importantly, the frequency
of MRD positivity was similar whether MRD
was determined in peripheral blood or bone
marrow (43% and 48%, respectively).”
Over a median follow-up of 6.2 years
(range not provided), 27 MRD-positive
patients (63%) and eight MRD-negative
patients (15%) experienced a post-alloHCT
relapse. This translated to a five-year
cumulative incidence of relapse (CIR) of
66 percent and 17 percent, respectively. In
univariate competing-risk analysis, MRD-
positive patients had a significantly higher
risk of relapse (hazard ratio [HR] = 5.58;
95% CI 2.47-12.59; p<0.001).
Survival also was shorter among MRD-
positive patients than MRD-negative patients:
• 5-year overall survival (OS): 41% vs.
78% (HR=3.06; 95% CI 1.53-6.12;
p=0.002)
• 5-year relapse-free survival (RFS):
31% vs. 74% (HR=3.56; 95% CI 1.86-
6.81; p<0.001)
However, there was no significant difference
in nonrelapse mortality between the two
MRD groups (HR=0.60; p=0.47).
MRD-positivity also was found to be
an independent predictor for CIR, OS,
and RFS in multivariate analyses adjusting
for mutation status, conditioning regimen,
and age ( TABLE 1 ).
“[This] NGS-based MRD monitoring
can be applied to a large proportion of AML
patients using almost any available molecu-
lar aberration and … is highly predictive of
relapse and survival when assessed in CR
prior to alloHCT,” the authors conclude.
Also, it overcomes limitations of available
MRD techniques for AML, which rely on
monitoring NPM1 markers that are present
only in a minority of patients with AML.
“NGS-MRD methods need to be
standardized, and this is now being
addressed by the European LeukemiaNet
MRD Working Party,” Dr. Heuser added.
“Next, we need to establish the clinical
benefit of MRD-guided treatment decisions
in prospective trials.”
The study was limited by its relatively
small sample size and the inclusion of pa-
tients receiving care from only one institu-
tion. In addition, the investigators suggested
that the NGS-based MRD technique is
limited by the clonal evolution of cells and
concerns about the assay’s sensitivity.
The authors report no conflicts of interest.
REFERENCE
Thol F, Gabdoulline R, Liebich A, et al. Multi-gene measurable residual disease
(MRD) monitoring by next-generation sequencing in AML is highly predictive
for outcome after allogeneic hematopoietic cell transplantation. 2018
September 6. [Epub ahead of print]
MRD Negativity Measured Via Next-Generation Sequencing
Predicts Long-Term Survival in Myeloma
Measuring minimal residual disease
(MRD) status using next-generation
sequencing (NGS) represented a prognos-
tic biomarker for survival in patients with
multiple myeloma (MM), according to
results from a study published in Blood.
MRD status also appeared to be a more
significant predictor of outcome than cy-
togenetic risk profile or disease stage, the
authors, led by Aurore Perrot, MD, PhD,
from the Université de Lorraine in France,
reported. Results from this trial supported
the U.S. Food and Drug Administration’s
approval of the clonoSEQ NGS assay for
MRD testing in patients with MM or acute
lymphocytic leukemia.
Researchers assessed the prognostic
value of MRD in patients with transplant-
eligible, newly diagnosed MM who were
enrolled in the phase III Intergroupe Franco-
phone du Myélome (IFM) 2009 trial. Per
study protocol, patients were randomized
to receive either conventional-dose strategy
(8 courses of lenalidomide, bortezomib,
dexamethasone [RVD]; n=264) or inten-
sive approach (3 courses of RVD followed
by high-dose melphalan and autologous
hematopoietic cell transplantation, followed
by consolidation with two more cycles of
RVD; n=245).
All participants received lenalidomide
maintenance therapy for 12 months.
At the start and end of the main-
tenance therapy period, researchers
collected bone marrow samples from all
patients; the extracted DNA was then sent
for sequencing with commercial NGS kits.
Assessment of MRD involved amplifying
the extracted DNA by polymerase chain
reaction with the use of immunoglobulin
gene-specific primers.
MRD negativity was defined as the
November 2018