Kategorie: Maligní lymfomy a leukémie
Číslo abstraktu: P606
Autoři: Mgr. Václava Polívková (Zmeková); MUDr. Peter Rohoň; Mgr. Nikola Čuřík, Ph.D.; MUDr. Hana Klamová, CSc.; MUDr. Olga Černá; RNDr. Martina Divoká; Jan Zach; RNDr. Martin Novák; MUDr. Iuri Marinov, CSc.; Simona Soverini; doc. MUDr. Edgar Faber, CSc.; Mgr. Kateřina Machová (Poláková), Ph.D.
CML patients in whom the tyrosine kinase inhibitor (TKI) therapy (imatinib, dasatinib, nilotinib) fails due to T315I BCR-ABL kinase domain mutation, should be switched to ponatinib or for bone marrow transplantation. However, in individual cases these treatment scenarios cannot be applied. We used treatment with interferon-α (IFN, given solo, sequentially or together with TKI) assuming that TKI-independent mechanism of action may lead to T315I mutant clone repression.
To study an effect of IFN-based treatment on mutated BCR-ABL transcript level and overall response of CML patients who failed on TKIs. In addition to that to assess the role of the sensitive measurement of BCR-ABL mutant mRNA load dynamics and immune response induced by IFN in individualized treatment.
Six CML patients who had failed on TKIs due to T315I or other highly resistant mutational profile have been treated with individual IFN-based treatment strategies. Kinase domain mutations in cDNA of BCR-ABL were analyzed in total 54 samples (median 6 samples of each patient, range 5-15) of peripheral blood leukocytes using next-generation deep sequencing (GS Junior, Roche Applied Science). The T315I clone reactivity on lowering imatinib concentration (2.0, 1.0, 0.4 and 0 µM imatinib) was studied in vitro on KCL22-R cell line resistant to 4.0 µM imatinib with 45% of BCR-ABL T315I. KCL22-R were incubated in each imatinib concentration for 14 days and checked for mutation. The basic immune-profile was analyzed in 5/6 CML patients using flow-cytometry detecting populations of CD4+, CD8+, regulatory T-cells (Tregs) and NK cells in specific time points (e.g. before IFN initiation, during IFN-based treatment).
The switch of TKI to IFN-based
treatment resulted in decreasing of mutated BCR-ABL mRNAs to
undetectable levels in 4/6 patients. Three of those patients
achieved major molecular response (MMR). IFN has been stopped,
based on non-mutated BCR-ABL transcripts detection, continuing with
solo nilotinib in 1/4 patient who achieved complete cytogenetic
remission (CCgR). One case of MMR responding patient on solo IFN
treatment showed decreased levels of CD3+ T-lymphocytes and
elevated levels of NK cells. Other two patients who achieved MMR
after IFN expressed elevated levels of NK cells representing
probably an immune activation on dasatinib pre-treatment following
with restoring immunological surveillance after application of
combined treatment IFN with TKI. In 2/6 cases TKI cessation and IFN
introduction did not contribute to the BCR-ABL mutations reduction
and response improvement.
No changes in the BCR-ABL T315I transcript levels have been observed after 14 days of incubation of KCL22-R upon easement of selective pressure of imatinib. We assume that longer time of incubation, which is ongoing, would be necessary to follow-up any changes.
In this work we showed that CML patients with TKI multi-resistant mutation T315I or other highly resistant BCR-ABL mutations may achieve CCgR or MMR thanks to IFN-based individualized treatment. These achievements may relate to immune-mediated anti-leukemic effects in this specific group of patients resulting in BCR-ABL clones repression. The sensitive measurement of mutated BCR-ABL transcript levels augments safety of this individualized treatment strategy.
Supported by IGA NT1389, by the project for conceptual development of research organization no. 00023736 of MZCR and IGA LF UP 01-2015.
Keyword(s): BCR-ABL, Chronic myeloid leukemia, Interferon alpha, Kinase domain mutant
Datum přednesení příspěvku: 13. 6. 2015