Department of Hematopathology Cytogenetic landscape and prognostic impact in blast phase of chronic myeloid leukemia Shimin Hu, MD, PhD Department of Hematopathology The University of Texas MD Anderson Cancer Center www.cml-mpn.com

Background Chronic myeloid leukemia (CML): myeloproliferative neoplasm BCR-ABL1/t(9;22)(q34;q11.2), variants, cryptic translocations (Ph) triphasic natural history: chronic phase (CP) accelerate phase (AP) blast phase (BP): 2/3 myeloid BP (MyBP), 1/3 lymphoid BP (LyBP) t(9;22): 1st chromosomal abnormality identified in cancer 1st translocation molecularly characterized 1st chromosomal abnormality resulting in successful target therapy

Background: patient outcome Pre-TKI (tyrosine kinase inhibitor) era: (no treatment, radiotherapy, busulfan or hydroxyurea) CP: median survival 3-5 years AP: median survival 1-2 years BP: median survival 3-4 months TKI era: CP: 8-year overall survival 87%; similar to the general population if CCyR achieved AP (initial): 8-year overall survival 75% BP: median survival < 1 year (7-10 months)

Background: disease progression Blastic transformation of CML-CP Pre-TKI era: most within 2-4 years; annual incidence of >20% TKI era: ~5%; annual incidence of 1-1.5% Clinical and laboratory parameters: WBC, PLT, basophil; blast; splenomegaly Cytogenetic and molecular genetics: additional chromosomal abnormalities (ACAs); mutations Treatment response parameters: TKI resistance (ABL1 dependent or independent) Risk factors for disease progression

Background: ACAs in pre-TKI era By disease stage: CP: <10%; AP: 20%; BP: 60-80% By ACA type: +8 34% +Ph 30% i(17q) 20% +19 13% Major-route ACAs: >10% of all cases with ACAs (changed to 5% later) Minor-route ACAs: others -Y 8.8% (male) +21 7% +17 5% -7 5% Impact: major-route but NOT minor-route ACAs confer worse prognostic impact in CP/AP; Controversial impact in BP Johansson B, et al. Acta Haematol 2002;107:76-94

Background: ACAs in TKI era Similar to pre-TKI era in frequency and pattern.? Impact: major-route but NOT minor-route ACAs confer worse prognostic impact in CP/AP; Unknown impact in BP. Management: major-route ACAs emerged during therapy indicate treatment failure; Major-route ACAs at diagnosis don not mandate differential treatment (ELN 2013). Baccarani M, et al. Blood 2013; 122: 872-884

Unanswered questions about CML-BP in TKI era ACA landscape in CML-BP? Similar to pre-TKI era? Prognostic impact of ACAs in CML-BP? Therapeutic goal in CML-BP? MMR, MR4, MUL? Or CCyR is adequate similar to that in CMP-CP?

Confounding: not all ACAs created equal All previous studies failed to take into consideration the complexity or the risk of each individual ACAs!!! 1. 47,XY,+8,t(9;22)(q34;q11.2)[20] 2. 46,XY,inv(3)(q21q26.2),t(9;22)(q34;q11.2)[20] Major route Minor route 1. 46,XY,t(9;22)(q34;q11.2)[20] 2. 47,XY,+8,t(9;22)(q34;q11.2)[20] 3. 48,XY,+8,t(9;22)(q34;q11.2),+19[20] 4. 49,XY,+8,t(9;22)(q34;q11.2),+19, +der(22)t(9;22)[20] Complex karyotype

Confounding factors in impact of ACAs +8 only (n=37) +8 with 1 additional ACAs (n=46) +8 with 2 additional ACAs (n=35) +8 with >2 additional ACAs (n=44) 50 100 150 200 25 75 Months O S a f t e r A C s m g n c p<0.0001 50 100 150 200 25 75 Months O S a f t e r C M L d i g n o s p<0.0001 Wang W, et al. Blood. 2016. Jun 2;127(22):2742-2750 Wang W, et al. Blood. 2015. Oct 1;126(14):1699-1706 Wang W, et al. Leukemia. 2015 Nov;29(11):2263-6

Unanswered questions about CML-BP in TKI era ACA landscape in CML-BP? Similar to pre-TKI era? Prognostic impact of ACAs in CML-BP? Therapeutic goal in CML-BP? MMR, MR4, MUL? Or CCyR is adequate similar to that in CMP-CP?

Patient cohort Inclusion criteria 354 patients with CML-BP diagnosed from 1999 to 2015. All patients received TKIs if diagnosed in BP; if diagnosed in CP or AP, all patients received TKIs before blastic transformation. Exclusion criteria Patients with cryptic BCR-ABL1 rearrangement. Patients with isolated myeloid sarcoma (without concurrent BP in bone marrow or peripheral blood. Chen Z, et al. Leukemia. 2017 Mar;31(3):585-592 Chen Z, et al. Leukemia. 2016 Jul;30(7):1606-1609 Chen Z, et al. Blood Cancer J. 2017 Feb 3;7(2):e521 Chen Z, et al. Blood Cancer J. 2016 May 6;6:e418

Patient cohort Demographics: 354 patients with CML-BP: 333 in CP/AP initially and BP later; 21 (5.9%) in BP initially; 214 (60.5%) men, 140 women; median age: 52 years (12-92) Lineage of BP: MyBP: 240 (67.8%) LyBP: 106 (29.9%) MPBP: 8 (2.3%) Treatment in BP: 323 (91.2%) received TKIs (+/- chemo) 31 (8.8%) received chemo only 91 (25.7%) received SCT Treatment response: < HR: 217 (61.3%) > HR: 137 (38.7%) > CCyR: 79 > MMR: 59 MUL: 48

Frequency of ACAs at diagnosis of CML-BP 270/354 Chen Z, et al. Leukemia. 2017 Mar;31(3):585-592 Chen Z, et al. Leukemia. 2016 Jul;30(7):1606-1609

Distribution of ACA types in CML-BP >10%: +8, +Ph, 3q26.2, -7, i(17q) >5%: +21, -Y, +19

Complexity of ACAs in CML-BP Simple: 68 (25.2%) Complex: 202 (74.8%)

Lineage specificity associated with ACAs LyBP: -7 MyBP: +8, 3q26.2, i(17q), +19 Both: +Ph, +21, -Y p=.53 p<.001 p=1.0 p=.047 p=.01 p=.27

ACA landscape in TKI vs pre-TKI eras

ACA landscape in TKI vs pre-TKI eras

ABL1 mutation and 3q26.2 rearrangement 20.0-52.4% for other ACAs

Impact of ACAs by lineage of blast phase

Impact of ACAs by frequency of ACAs

Impact of ACAs by emerging time of ACAs

Impact of ACAs by complexity and risk of ACAs Complex karyotype: Ph + >2 ACAs High-risk ACAs: 3q262.2, -7/7q-, i(17q)

Impact of allo-HSCT in CML-BP with ACAs

Relationship between ACAs in CML-BP Pearson correlation analysis A B 1 0.283 0.025 0.225 -0.205 -0.380 0.155 0.244 0.117 -0.086 -0.114 -0.040 0.112 -0.095 -0.153 -0.169 -0.284 -0.245 -0.063 -0.096 -0.229 -0.173 Subgroup 1: 3q26, -7/7q-, i(17q) Subgroup 2: +8, +9, +21, +Ph

Risk stratification of ACAs in CML-CP 50 100 150 200 25 75 Months O S a f t e r A C s m g n c 3q26.2 i(17q) +Ph -Y -7/7q- +8 Other single Subgroup 2 Subgroup 1 Wang W, et al. Blood 2016 Jun 2;127(22):2742-2750 Wang W, et al. Blood 2015 Oct 1;126(14):1699-170

Treatment response for optimal outcome in CML-BP 1 2 3 MUL/CMR: similar to AML with favorable cytogenetics MMR: similar to AML with intermediate cytogenetics CCyR: similar to AML with unfavorable cytogenetics Chen Z, et al. Blood Cancer J. 2017 Feb 3;7(2):e521

SUMMARY +8, +Ph, 3q26.2 rearrangement, -7 and i(17q) have a frequency >10% (major-route); +21 and +19 have a frequency >5%. +8, 3q26.2 rearrangement, i(17q) and +19 are common in MyBP; -7 more common in LyBP; +Ph and +21 are equally distributed between MyBP and LyBP. There is significant shift in the distribution of ACAs in TKI vs pre-TKI eras. The emergence of 3q26.2 rearrangement as a major-route ACA in TKI era correlates with the high frequency of ABL1 mutations.

SUMMARY ACAs confer a negative prognostic value in MyBP but not LyBP. However, the nature, the frequency or the emerging time of ACAs have no prognostic relevance. The adverse impact of ACAs can be overcome by allo-SCT. Pearson correlation analysis reveals two subgroups of ACAs. The subgrouping of ACAs correlates with their prognostic impact in CML-CP/AP, supporting their role in blastic transformation. Differential depth of treatment response is required for optimal outcome in CML-BP vs in CML-CP (CMR vs CCyR).

ACKNOWLEDGEMENT Hu Lab: Department of Hematopathology Yan Li, MD, PhD Shi Bai, MD, PhD Parsa Hodjat, MD Lianghua Fang, MD, PhD Zhihong Hu, MD, PhD Christina Regmi, MA, MS Vanya Jaitly, MD Hui Liu, MD, PhD Andy Ai, MD, PhD Wei Wang, MD, PhD Wen Yang, MD, MS Wei Liu, MD, PhD Zimu Gong, MD Lan Zheng, MD, PhD Zi Chen, MD, PhD Habibe Kurt, MD Hu Lab: Wei Xie, MD, PhD Arash Ronaghy, MD, PhD Department of Hematopathology Bone marrow laboratory Cytogenetics laboratory Molecular diagnostic laboratory Department of Leukemia CML section