Rapid clonal selection within early hematopoietic cell compartments presages the outcome of ivosidenib combination therapy

S Sven Turkalj F Felix A. Radtke B Bilyana Stoilova (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) R Rabea Mecklenbrauck A Angus J. Groom (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) N Niels Asger Jakobsen C Curtis A. Lachowiez (Oregon Health & Science University, Portland, Oregon, United States) M Marlen Metzner (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) B Batchimeg Usukhbayar (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) M Mirian Angulo Salazar (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) Z Zhihong Zeng (2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX) S Sanam Loghavi J Jennifer Marvin-Peek (2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX) V Verena Körber F Farhad Ravandi (Department of Leukemia The University of Texas MD Anderson Cancer Center Houston Texas USA) G Ghayas Issa (2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX) T Tapan Kadia (2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX) V Vasiliki Symeonidou (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) A Anne P. de Groot (1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom) H Hagop Kantarjian (2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX) K Koichi Takahashi M Marina Konopleva C Courtney D. DiNardo (Department of Leukemia The University of Texas MD Anderson Cancer Center Houston Texas USA) P Paresh Vyas

Abstract

Abstract Acquired resistance to targeted, nonintensive therapies is common in myeloid malignancies. However, the kinetics of selection, the hematopoietic cell compartments in which selection occurs, and the molecular mechanisms underlying selection remain open questions. To address this, we studied the kinetics of clonal and transcriptional responses to combinational therapy with ivosidenib plus venetoclax, with or without azacitidine, across hematopoiesis in 8 patients with IDH1-mutant myeloid malignancy. All 8 patients initially responded to treatment, but 6 relapsed, whereas 2 remained in sustained remission for >4 years. We performed combined high-sensitivity single-cell genotyping and scRNA sequencing in index-sorted sequential patient samples. In all patients, clonal selection occurred rapidly, within 1 to 3 treatment cycles. Clonal selection preceded treatment failure by months to years. Relapse was associated with expansion of either clones harboring newly detected myeloid driver mutations or preexisting minor clones that underwent differentiation delay upon treatment exposure. In both cases, clonal selection occurred within immature cell populations previously shown to contain leukemic stem cell potential. Different genetic alterations within relapse-associated clones converged onto common upregulated transcriptional programs of stemness, branched-chain amino acid catabolism, and genes sensitive to menin inhibition. Importantly, this relapse-associated transcriptional signature was selected within 3 cycles of therapy. In contrast, in both patients remaining in remission, leukemic clones were rapidly eradicated, and replaced by clonal and wild-type hematopoiesis. Overall, in patients treated with ivosidenib combination therapy, rapid clonal selection occurs within the first treatment cycles. In those patients destined to relapse, genetically heterogeneous resistant clones are characterized by common transcriptional programs.

Article Details

Journal Blood
Volume / Issue Vol. 147, Issue 6
Published February 05, 2026
Pages 613-632
ISSN 0006-4971
Publisher Elsevier BV

Journal Info

Blood

Elsevier BV

ISSN: 0006-4971 Health Sciences

Authors (24)

S

Sven Turkalj

F

Felix A. Radtke

B

Bilyana Stoilova

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

R

Rabea Mecklenbrauck

A

Angus J. Groom

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

N

Niels Asger Jakobsen

C

Curtis A. Lachowiez

Oregon Health & Science University, Portland, Oregon, United States

M

Marlen Metzner

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

B

Batchimeg Usukhbayar

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

M

Mirian Angulo Salazar

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

Z

Zhihong Zeng

2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX

S

Sanam Loghavi

J

Jennifer Marvin-Peek

2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX

V

Verena Körber

F

Farhad Ravandi

Department of Leukemia The University of Texas MD Anderson Cancer Center Houston Texas USA

G

Ghayas Issa

2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX

T

Tapan Kadia

2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX

V

Vasiliki Symeonidou

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

A

Anne P. de Groot

1Medical Research Council Molecular Haematology Unit, Radcliffe Department of Medicine, Weatherall Institute of Medicine, University of Oxford, Oxford, United Kingdom

H

Hagop Kantarjian

2Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX

K

Koichi Takahashi

M

Marina Konopleva

C

Courtney D. DiNardo

Department of Leukemia The University of Texas MD Anderson Cancer Center Houston Texas USA

P

Paresh Vyas