When to change therapy? Andreas Hochhaus Universitätsklinikum Jena, Germany

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1 When to change therapy? Andreas Hochhaus Universitätsklinikum Jena, Germany

2 Chromosome 22 Chromosome 9 e1 1b m-bcr M-bcr e1 e2 b1 b5 5 3 BCR ABL 5 3 1a a2 a3 μ -bcr e19 a11 e1a2 b2a2 b3a2 e19a2 p190 bcr-abl p210 bcr-abl p230 bcr-abl

3 Detection of typical and rare BCR-ABL transcripts by multiplex PCR M e19a2 SD1 e1a2 K562 b3a2 healthy donor negative control M e19a2 BCR-ABL BCR e1a2 BCR-ABL b3a2 BCR-ABL Cross et al Leukemia 1994

4 Goals of CML Therapy Leukemia cells > CHR CCyR MMR/CMR Undetectable range

5 karyotype: 46,XY,t(9;22)(q34;q11) 9q+ 22qb3a2 b2a2 b3a2/ b2a2 b3a3 b2a3

6 LightCycler HybProbes BCR-ABL b2 b3 a2 a3 a4 B2A NA4- ABL Ia Ib a2 a3 a4 Emig et al. Leukemia A2N NA4- TaqMan ENP541 BCR-ABL b2 b3 a2 a3 a4 ABL ENF402 Ia Ib ENR561 ENP1043 a2 a3 a4 Gabert et al. Leukemia ENF1003 ENR1063

7 Real time quantitative RT-PCR I. Hydrolysis Probes Release from quenching by hydrolysis hν X II. Hybridization Probes Increased resonance energy transfer by hybridization hν X hν x 10 4 BCR-ABL plasmid molecules x = 40,000 hν X X TaqMan TM LightCycler TM

8 Rationale for response monitoring Most patients in CP have a good response to imatinib Some patients, however, still progress Identify patients who will ultimately experience relapse Early identification of relapse or progression provides an opportunity for alternative therapy Identification of patients in stable remission after TKI withdrawal

9 Progression-free Survival on 1 st line Imatinib by Cytogenetic Response at 6 Months % without progression IRIS Study, Update ASH, Any CyR No CyR Cyr p<0.001 Estimated rate (95% CI) at 42 months: n=410 91% (87-94) n=119 68% (59-77) Months since randomization

10 Ph chromosome and BCR-ABL transcript numbers as measures of residual leukemia during treatment (Copy numbers with Abl as control gene) Decreasing residual leukemia BCR-ABL/ABL ratio (%) Leukocytosis Ph-chromosome pos Ph-negative but RT-PCR positive RT-PCR negative Number of leukemia cells (log 10 ) 0 Cure? 1 0

11 Progression-free Survival on 1 st -line Imatinib by Molecular Response (MR) at 12 Months % without progression IRIS Study, Update ASH, No CCyR <3 log reduction >=3 log reduction p<0.001 Estimated rate (95% CI) at 42 months: n=138 75% (67-84) n= 94 90% (84-97) n=136 98% (96-100) Months since randomization

12 % Without Event 100 Imatinib: EFS: 6-Month Landmark Analysis BCR-ABL % (IS) <=0.01% 0.1% (n = 86) >0.1-1% (n = 89) >1-10% (n = 43) >10% (n = 38) Months Since Start of Treatment 93% 85% 85% 56% P =.25 Hughes et al., ASH 2008

13 Imatinib: EFS: 12-Month Landmark Analysis % Without Event BCR-ABL % (IS) <=0.01% 0.1% (n = 153) >0.1-1% (n = 90) >1-10% (n = 36) >10% (n = 22) Months Since Start of Treatment 92% 91% 64% 53% P =.25 Hughes et al., ASH 2008

14 Imatinib: EFS: 18-Month Landmark Analysis % Without Event BCR-ABL % (IS) <=0.01% 0.1% (n = 164) >0.1-1% (n = 47) >1-10% (n = 25) >10% (n = 13) Months Since Start of Treatment 95% 86% 62% 58% P =.01 Hughes et al., ASH 2008

15 Imatinib: Progression to AP/BC - 18-Month Landmark Analysis % without AP/BC BCR-ABL % (IS) <=0.01% 0.1% (n = 164) >0.1-1% (n = 47) >1-10% (n = 25) >10% (n = 16) Months Since Start of Treatment 99% 96% 83% 81% P =.0003 ( 0.1% vs. >0.1%) P =.054 Hughes et al., ASH 2008

16 Criteria for Failure and Suboptimal Response to Imatinib Time (mo) Response Failure Suboptimal Optimal 3 No CHR No CG Response <65% Ph+ 6 No CHR >95% Ph+ 35% Ph+ 35% Ph % Ph+ 1-35% Ph+ 0% Ph+ 18 5% Ph+ No MMR MMR Any Loss of CHR Loss of CCgR Mutation CE Loss of MMR Mutation Stable or improving MMR Baccarani et al. JCO 2009; 27:

17 Ph chromosome and BCR-ABL transcript numbers as measures of residual leukemia during treatment (Log reduction from 100% or log 0) Decreasing residual leukemia CCyR MMR Log reduction from baseline Leukocytosis Ph-chromosome pos RQ-PCR <3 log red. RQ-PCR >3 log red. RQ-PCR negative (undetectable) Number of leukemia cells (log 10 ) 0 Cure? 1 0

18 The evidence obtained with the IRIS study is that the absolute and not the relative amount is important! 100 Starting amount 9th month rd month 6th month 12th month 10 CCyR1 0,1 Minor Molecular Response 0,01 Major Molecular Response 0,001 0,0001

19 Converting to International Scale Log reduction of BCR-ABL Base line Standardised Baseline Ph-negativity Major molecular response International scale Adelaide 100% 80% 10% 8% 1% 0.8% 0.1% 0.08% 0.01% 0.008% Pre Months from the start of Imatinib 42

20 Variability of Ratios BCR-ABL/ABL (%) in 36 laboratories CV 0.62 negative b3a2 10 % b3a2 2 % b3a2 1 % b3a2 0.1 % b3a2 neg b2a2 10 % b2a2 2 % b2a2 1 % b2a2 0.1 % b2a2 neg Ratio BCR-ABL/ABL (%) Müller et al., Leukemia 2007

21 BCR-ABL levels in 58 labs pre and post conversion BCR-ABL CV MMR Level 1 Level 2 Level 3 Level 4 Level 1 Level 2 Level 3 Level 4 reference results BCR-ABL L pre conversion BCR-ABL IS post conversion

22 30

23 Why do patients fail imatinib? Apperley, Lancet Oncology 2007

24 Kinase domain mutations T315I (G A) Q252H (G C) -7

25 ELN Recommendations Hematologic response Cytogenetic response Molecular response 2 weekly until CHR confirmed 6 monthly until CCR confirmed 12 monthly 3 monthly MMR Baccarani et al, Blood;2006;108;1809

26 ELN Recommendations Molecular response Mutation Cyto analysis response 3 monthly no MMR by 18m loss of MMR 5fold rise in BCR-ABL Baccarani et al, Blood;2006;108;1809

27 Andreas Hochhaus Universitätsklinikum Jena Jena, Germany

28 Andreas Hochhaus Universitätsklinikum Jena Jena, Germany

29 Andreas Hochhaus Universitätsklinikum Jena Jena, Germany