Download Tests and Treatment Responses In Chronic Phase CML

Tests and Treatment Responses
In Chronic Phase CML
A tool to assist health care professionals to communicate with their patients
about the different types of tests used for the diagnosis of CML, monitoring
response to TKI therapy and mutational analysis as outlined in the NCCN Clinical
Practice Guidelines in Oncology (NCCN Guidelines®).
OVERVIEW
Chronic myelogenous leukemia (CML) is the cancer of blood-forming cells in the bone marrow. CML
is a slow growing cancer that causes an increase in the number of white blood cells. CML is caused by
the reciprocal translocation between chromosomes 9 and 22. The BCR gene located on chromosome 22
and the ABL1 gene located on chromosome 9 join together to form the BCR-ABL1 fusion gene. This
translocation also creates a longer chromosome 9 and a shorter chromosome 22, which is called the
Philadelphia (Ph) chromosome. CML occurs in three different phases (chronic, accelerated, and blast
phase) and is usually diagnosed in the chronic phase. Tyrosine kinase inhibitor (TKI) therapy with small
molecules that target the BCR-ABL1 protein is the standard of care for all patients with newly diagnosed
chronic phase CML.
TESTS
Bone marrow cytogenetics detects and measures the number of cells in the bone marrow that contain
the Ph chromosome. It is performed at diagnosis to establish the disease phase. Fluorescence in-situ
hybridization (FISH) on a peripheral blood specimen using dual probes for the BCR and ABL genes can
be used, if collection of bone marrow is not possible. Quantitative reverse transcriptase polymerase
chain reaction (QPCR) is the most sensitive test that detects and measures the BCR-ABL1 gene in a
peripheral blood specimen. QPCR should be done at diagnosis to establish the BCR-ABL1 transcript
levels at baseline. BCR-ABL1 kinase domain mutational analysis detects new mutations in the
BCR-ABL1 gene that may occur during treatment for CML. Mutational analysis helps to select an
alternate TKI therapy when CML is not responding to a particular TKI therapy.
TREATMENT RESPONSES
Monitoring response to TKI therapy is one of the key management strategies of CML. Hematological
response measures normalization of the blood counts, particularly white blood cell counts. Cytogenetic
response measures the decrease in the number of bone marrow cells that have the Ph chromosome.
Molecular response measures the decrease in the number of cells in the peripheral blood that contain
the BCR-ABL1 gene. QPCR is the only test capable of monitoring molecular response to TKI therapy after
the patient has achieved complete cytogenetic response (CCyR). QPCR should be performed in a lab that
uses the International Scale (IS) that was established to standardize the measurement of
molecular response across different laboratories. In the QPCR (IS), results are expressed as the ratio of
BCR-ABL1 gene transcripts to the number of control gene transcripts (BCR, ABL1, or GUSB).
Laboratories with no access to QPCR (IS) may establish their own standardized baseline, based on a
large number of pre-treatment samples. Molecular response is then measured as the log-reduction
of BCR-ABL1 transcripts from the standardized baseline (not a reduction from the actual
baseline level in an individual patient).
NCCN.org Page 1 of 4
TREATMENT RESPONSE CRITERIA
Hematologic
Response
Cytogenetic
Response
Molecular
Response
NCCN.org Complete Hematologic
Response (CHR)
Peripheral blood counts and platelet counts
completely normal;
No blasts or immature cells in the peripheral
blood and no signs or symptoms of disease
including no enlarged spleen
Complete Cytogenetic
Response (CCyR)
No Ph chromosome is detectable in bone
marrow cytogenetics
Partial Cytogenetic
Response (PCyR)
1%–35% of cells have the Ph
chromosome on bone marrow cytogenetics
Major cytogenetic
response (MCyR)
0%–35% of cells have the Ph
chromosome on bone marrow cytogenetics
Complete Molecular
Response (CMR)
No BCR-ABL1 transcripts are detectable in
peripheral blood by QPCR using IS
Early molecular
response (EMR)
BCR-ABL1 ≤10% by QPCR using
IS at 3 or 6 months
Major molecular
response (MMR)
BCR-ABL1 0.1% by QPCR using IS or at least
a 3-log reduction in the BCR-ABL1 transcript
levels from the standardized baseline (if QPCR
using IS not available)
Page 2 of 4
MONITORING RESPONSE TO TKI THERAPY AND MUTATIONAL ANALYSIS
RESPONSE MILESTONES
TEST
TEST
SAMPLE
AT
DIAGNOSIS
ANYTIME DURING THERAPY
BCR-ABL1/ABL1 ≤10% by
QPCR using IS or
PCyR on Bone Marrow Cytogenetics
QPCR (IS)
Peripheral
Blood or Bone
Marrow
ü
CCyR
3 MONTHS
6 MONTHS
12 MONTHS
18 MONTHS
ü
ü
ü
ü
Every 3 months after initiation of TKI therapy until CCyR is achieved.
Repeat QPCR (IS) in 1–3 months if
there is 1-log increase in BCR-ABL1
transcript levels with a MMR
Every 3 months for 3 years and every 3–6 months thereafter, after CCyR has
been achieved:
Bone marrow
Cytogenetics
BCR-ABL1
kinase domain
mutation
analysis
NCCN.org Bone Marrow
Peripheral
Blood or Bone
Marrow
ü
If QPCR using IS not available
If there is no
CCyR or MMR
Any sign of loss of response
(hematologic or cytogenetic relapse)
BCR-ABL1/ABL1 >10% by QPCR
using IS
or
Lack of PCyR on bone marrow
cytogenetics
If not in MMR and
1-log increase in BCR-ABL1
lack of CCyR at
transcript levels without a MMR
12 months
Less than a CCyR
1-log increase in BCR-ABL1
transcript levels and loss of MMR
Disease progression to accelerated
or blast phase
Page 3 of 4
REFERENCES
1. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidlines®), Chronic Myelogenous Leukemia,
Version 1.2015.
2. Radich JP. Monitoring response to tyrosine kinase inhibitor therapy, mutational analysis, and new
treatment options in chronic myelogenous leukemia. J Natl Compr Canc Netw. 2013;11(5 Suppl):663-6.
3. Baccarani M, Deininger MW, Rosti G, et al. European LeukemiaNet recommendations for the
management of chronic myeloid leukemia: 2013. Blood. 2013;122(6):872-84.
4. Jabbour E, Branford S, Saglio G, et al. Practical advice for determining the role of BCR-ABL
mutations in guiding tyrosine kinase inhibitor therapy in patients with chronic myeloid leukemia.
Cancer. 2011;117(9):1800-11. Erratum in: Cancer. 2011;117(15):3535.
5. Hughes T, Deininger M, Hochhaus A, et al. Monitoring CML patients responding to treatment with
tyrosine kinase inhibitors: review and recommendations for harmonizing current methodology for
detecting BCR-ABL transcripts and kinase domain mutations and for expressing results. Blood
2006;108:28-37.
This tool was produced in combination with a live and enduring educational activity.
This activity is supported by an educational grant from Bristol-Myers Squibb.
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