The concept of TFR (Treatment Free Remission) in CML

The concept of TFR (Treatment Free Remission) in CML Giuseppe Saglio University of Turin, Italy

What can we expect today on long-term therapy with TKIs in CML?

German CML study IV Relative and overall survival, n = 1536 Have we solved all the problems? Patients at risk: 1536 (OS and RS) 1536 1261 522 218 Hehlmann R. et al, Leukemia 2017

German CML study IV - Patients disposition at 10 years 100 10 37% 46% Hehlmann R et. Al, Leukemia 2017

ENESTnd Study K-M Analysis Regarding the Incidence of CVEs Over Time. CMLPPT/ONCO/814190/07/SEP/2017 Hochhaus et al., Leukemia 2016

Frequency of new and recurrent PE from each patient throughout dasatinib therapy (35 of 65 IM failed patients) Kim DH, et al. Int J Hematol. 2011 Oct;94(4):361-71

Imatinib long term effects: ILTE study Independent study 957 enrolled patients in CCyR for at least 2 years endpoints: SAE e NSAE 100 SAE, 21% only related to imatinib (> heart failure ) 576 NSAE, 71% related to imatinib: edema, cramps, GI toxicity etc 27 patients developed other neoplasias (similar to that of a control population without leukemia Gambacorti-Passerini C et al. JNCI 2011

It would be nice to discontinue the TKI therapy...., but is it possible to discontinue TKI therapy in CML without facing a relapse? Yes, it is!

Survival without molecular recurrence STIM 1 100 90 80 70 60 50 40 30 20 10 0 The median molecular follow-up after treatment discontinuation is 77 months (range 9 95 months) 0 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 Months since discontinuation of imatinib Etienne G, et al. JCO 2017.

Sensitive Evaluation of BCR-ABL amount by Digital PCR Goh et al. Leukemia &Lymphoma 2011

BCR-ABL/ABL % After discontinuation, some patients may show reappearance and fluctuation in MRD Ara-C CML patient in CP 31 years old Low-risk Sokal score 100 Imatinib 400 mg/d Stop imatinib 10 1 0.1 0.01 0.001 Undetectable -5-4 -3-2 -1 0 1 2 3 4 5 Years Rousselot P, personal data.

R e m is s io n w ith o u t th e ra p y (% ) Treatment free remission using loss of MMR to define molecular relapse 1 0 0 8 0 61% 6 0 4 0 2 0 0 0 1 2 2 4 3 6 4 8 6 0 7 2 8 4 M o n th s P ts a t ris k 80 51 33 24 17 10 7 1 Rousselot P et al., J Clin Oncol. 2014 Feb 10;32(5):424-30

Which are the patients in which it is possible to try to stop the TKI therapy?

EURO-SKI study design Inclusion criteria TKI treatment at least 3 years Study start MR 4 at least 1 year Screening phase (confirming MR 4 ) q4w RQPCR q6w RQPCR Every 3 rd month < 6 weeks Year 1 Year 2 Year 3 Follow-up Informed consent Stop TKI Relapse defined as BCR-ABL >0.1% (loss of MMR) at one time point Saussele S et al. Lancet Haematology 2018

Patient characteristics Patients included N = 755 Sex, Female % 47.9 Age at diagnosis, median years (range) 52 (11 86) Age at stopping, median years (range) 61 (20 90) Duration of TKI treatment, years (range) 8 (3 14) Duration of MR4 before stopping TKI, years (range) 5 (1 13) High risk, % EUTOS Sokal 8 17.5 Saussele S et al. Lancet Haematology 2018

Probability of loss of MMR Prognostic modeling (n = 405, imatinib) Using the minimal p-value approach, a 3.1-year cut-off was significant and chosen with respect to patient safety* 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 MR4 < = 3.1 yrs, 6 mo. prob.: 56%, 95% CI: 47 64% MR4 > 3.1 yrs, 6 mo. prob.: 38%, 95% CI: 33 44% 0 6 12 18 24 30 36 Months since discontinuation of imatinib *20% of patients in the smallest group. Saussele S et al. Lancet Haematology 2018

Probability of loss of MMR Treatment duration cut-off for loss of MMR at 6 months Identified with the minimal p-value approach 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 TKI < = 5.8 yrs, 6 mo. prob.: 57%, 95% CI: 48 64% TKI > 5.8 yrs, 6 mo. prob.: 34%, 95% CI: 29 39% It means that we tested for several cut-off candidates. We chose the one with the minimal p-value. That is, the one which separates two groups with most significant differences with regard to the MMR status at 6 months. 0 6 12 18 24 30 36 Months since discontinuation of imatinib EURO-SKI presented by FX Mahon at ASH 2016.

Moving treatment-free remission into mainstream clinical practice in CML Criteria GREEN YELLOW RED Institutional criteria met (per Table 1) Yes No Sokal score at diagnosis Non-high High BCR-ABL transcript at diagnosis Typical B2A2 or B3A2 (e12a2 or e14a2) Atypical, but can be accurately quantified CML past history CP only Resistance or KD mutation Not quantifiable Prior AP or BC Response to first-line TKI therapy Optimal Warning Failure Duration of all TKI therapy >8 years 3 8 years <3 years Depth of deep molecular response MR4.5 MR4.0 Not in MR4.0 Duration of DMR monitored in a standardized laboratory >2 years 1 2 years <1 year ALL GREEN lights: strong recommendation to consider TKI withdrawal ANY YELLOW lights: only consider TKI withdrawal in high priority circumstances (e.g. significant toxicity or planned pregnancy) ANY RED lights: TKI withdrawal not recommended Hughes TP, Ross DM. Blood. 2016 Mar 24. pii:blood-2016-01-694265.

NCCN guidelines 2018 Criteria for TKI discontinuation Age 18 years Chronic phase CML. No prior history of accelerated or blast phase CML On approved TKI therapy for at least 3 years Prior evidence of quantifiable BCR-ABL transcript Stable molecular response (MR4; BCR-ABL1 0.01% IS) for 2 years, as documented on at least four tests, performed at least 3 months apart No history of resistance to any TKI Access to a reliable Q-PCR test with a sensitivity of detection of 4.5 logs that reports results on the IS and provides results within 2 weeks NCCN Clinical Practice Guidelines in Oncology, Chronic Myeloid Leukemia. Version 1.2018.

ESMO recommendations for TFR Green criteria, which support treatment-free remission 1. Institutional criteria met 2. Sokal Score at diagnosis non-high 3. Typical b2a2- or b3a2-bcr-abl1 transcripts, or atypical transcripts which can be quantified over a 4.5 log dynamic range 4. Chronic phase disease 5. Optimal response to first-line therapy 6. Duration of TKI therapy >5 years 7. MR4.5 reached 8. Duration of deep molecular response (MR4 or MR4.5) >2 years Hocchaus et al, Annals of Oncology 2017.

Summary of Steering Group recommendations derived from patient-physician discussion The following factors should be considered before attempting TFR: Patients were in the chronic phase of CML at diagnosis, not have experienced resistance to any TKI therapy at any time, and to have been in DMR for at least 2 years Patients need to be well-informed about TFR, well-motivated to discontinue treatment, but not under pressure to stop therapy Patients should fully understand that molecular recurrence is not a failure, and that treatment will be restarted Molecular monitoring test results should be available within 4 weeks Saglio G.et al, Clinical Lymphoma Myeloma and Leukemia. 2018

How many are the patients in which it is possible to try to stop the TKI therapy?

Patients With MR 4.5, % ENESTnd 5 Year Update Cumulative Incidence of MR 4.5 100 90 Nilotinib 300 mg BID (n = 282) Nilotinib 400 mg BID (n = 281) Imatinib 400 mg QD (n = 283) 80 70 By 4 Years a By 5 Years a 60 50 By 1 Year a 40%, P <.0001 54%, P <.0001 52%, P <.0001 40 37%, P =.0002 Δ 21% to 23% 30 20 10 0 11%, P <.0001 Δ 14% to 17% 31% Δ 6% to 10% 7%, P <.0001 1% 23% 0 1 2 3 4 5 6 Time Since Randomization, Calendar Years MR 4.5, molecular response 4.5-logs (BCR-ABL IS 0.0032%). a Cumulative response rates reported consider each year to consist of twelve 28-day cycles. Hochhaus A.et al, Leukemia 2016

Patients who met stringent criteria for attempting TFR in the ENESTnd study Nilotinib 300 mg BID 37.9% Imatinib 400 mg QD 21.6% Hochhaus A. et al, ASH 2015

In which way we can achieve the conditions in which it is possible to try to discontinue the TKI therapy?

Enroll Adults with CML-CP b2a2 and/or b3a2 transcripts 2 years of frontline nilotinib ENESTfreedom study design a Nilotinib Frontline RQ-PCR (standardized to the IS) every 12 weeks Nilotinib consolidation phase (52 weeks) Sustained DMR b STOP RQ-PCR (standardized to the IS) every 4 weeks for the first 48 weeks, every 6 weeks for the second 48 weeks, and then every 12 weeks TFR phase (up to 192 weeks after last patient enters TFR phase) MR 4.5 at screening (central laboratory) Loss of MMR Primary endpoint: proportion of patients with no loss of MMR and no treatment reinitiation by week 48 of TFR Data cutoff date: 30 November 2015 Nilotinib treatment reinitiation phase DMR, deep molecular response; IS, International Scale; MMR, major molecular response (BCR-ABL1 IS 0.1%); MR 4, BCR-ABL1 IS 0.01%; MR 4.5, BCR-ABL1 IS 0.0032%; RQ-PCR, real-time quantitative polymerase chain reaction. a ClinicalTrials.gov identifier: NCT01784068. b Sustained DMR is defined as the following (in the last 4 quarterly PCR assessments): MR 4.5 in the last assessment, no assessment worse than MR 4, and 2 assessments between MR 4 and MR 4.5.

Enroll Adults with CML-CP 3 years of TKI therapy (imatinib for > 4 weeks, then nilotinib for 2 years) No documented MR 4.5 at time of switch to nilotinib Achieved MR 4.5 on nilotinib ENESTop study design a Second-line Nilotinib therapy RQ-PCR (standardized to the IS) every 12 weeks Nilotinib consolidation phase (52 weeks) No confirmed b loss of MR 4.5 STOP RQ-PCR (standardized to the IS) every 4 weeks for the first 48 weeks, every 6 weeks for the second 48 weeks, and then every 12 weeks TFR phase (up to 192 weeks after last patient enters TFR phase) Loss of MMR or confirmed c loss of MR 4 Primary endpoint: proportion of patients with no loss of MMR or confirmed c loss of MR 4 and no treatment reinitiation by week 48 of TFR Data cutoff date: 26 November 2015 Nilotinib treatment reinitiation phase a ClinicalTrials.gov identifier: NCT01698905. b Defined as loss of MR 4.5, confirmed in a second assessment within 4 weeks. c Defined as loss of MR 4, confirmed in a second assessment within 4 weeks.

Treatment-free survival, % ENESTfreedom: TFR rate at 96 weeks TFR rate at 96 weeks, 93/190 (48.9% [95% CI, 41.6%-56.3%]) 88 of 190 patients also had MR 4.5 100 90 80 70 60 50 40 Kaplan-Meier analysis of TFS a,b Estimated rate of TFS at 96 weeks, 50.9% (95% CI, 43.6%-57.8%) 30 20 10 0 Patients Events Censored 190 94 96 Censored observations 0 12 24 36 48 60 72 84 96 108 120 132 144 Time since TFR start, weeks At risk: events: 190:0 120:70 99:89 95:91 75:93 8:93 0:94 a Defined as the time from the start of TFR until the earliest of any of the following: loss of MMR, reinitiation of nilotinib for any reason, progression to AP/BC, or death due to any cause. b By the data cutoff date, 1 patient lost MMR at week 120, at which time only 8 patients were considered to be at risk, resulting in the artificial drop seen at the end of the curve. From Ross D, et al. In: Proceedings from the European Hematology Association; June 22-25, 2017; Madrid Spain [abstract P601]. Ross D, et al. Haematologica. 2017:102 [abstract P601].

Treatment-free survival, % ENESTop: TFR rate at 96 weeks TFR rate at 96 weeks, 67/126 (53.2% [95% CI, 44.1%-62.1%]) 100 90 80 Kaplan-Meier analysis of TFS a The TFS curve appeared to plateau after 24 weeks Median duration of TFS was not reached by the 96-week data cutoff 70 60 50 40 30 20 10 0 Patients Events Censored 126 57 69 Censored observations 0 12 24 36 48 60 72 84 96 108 120 132 144 Time since TFR, weeks At risk: events: 126:0 107:19 76:49 74:51 73:52 72:53 71:53 69:54 54:55 32:56 13:57 1:57 0:57 a Defined as the time from the start of TFR until the earliest of any of the following: loss of MMR, confirmed loss of MR 4, reinitiation of nilotinib for any reason, progression to AP/BC, or death due to any cause. Reprinted from Hughes T, et al. Haematologica. 2017;102(s2) [abstract [P257]. Copyright 2017 with permission from the Ferrata Storti Foundation. Obtained from the Haematologica Journal website http://www.haematologica.org. Hughes T, et al. Haematologica. 2017:102 [abstract P257].

Characteristics of the TFR Population ENESTfreedom (n = 190) ENESTop (n = 126) Age, median (range), years 55 (21-86) 56 (21-86) Time from MR 4.5 to study entry, 18.3 (0.3-71) median (range), months a 1.5 years 19.8 (0-78) 1.6 years Duration of nilotinib treatment prior to TFR, median (range), months 43.5 (33-89) 53.0 (37-109) Duration of total TKI treatment prior to TFR, median (range), months 43.5 (33-89) 3.6 years 87.7 (49-171) 7 years Actual nilotinib dose intensity during consolidation phase, median, mg/day 600 772 a Indicates time to study entry from first MR 4.5 (ENESTfreedom) or from achievement of MR 4.5 with nilotinib (ENESTop).

DASFREE Study Design (CA180-406/NCT01850004) DASFREE is a phase 2, open-label, single-arm study conducted in North America and Europe Eligible patients were required to be in DMR (MR 4.5 or BCR-ABL1 0.0032% on the IS) Screening Dasatinib treatment for 2 years as first-line or subsequent therapy Dasatinib-induced DMR for 1 year prior to enrollment, confirmed by prescreening and 2 central lab assessments 3 months apart a,b Discontinue dasatinib (N = 84) If loss of MMR, restart at dose at enrollment All patients (N = 84) had 1 year of follow-up in this analysis Follow-up up to 5 years a Adults with dasatinib-induced stable DMR for 9 months, documented by 3 assessments conducted 2 to 6.5 months apart at a local lab were screened. b For any patient not eligible for enrollment because both assessments at the central lab did not confirm DMR, rescreening was allowed 9 months after the last central lab screening failure. DMR = deep molecular response; IS = International Scale; MMR = major molecular response; MR 4.5 = molecular response with 4.5-log reduction of BCR-ABL1 transcripts. 31 Shah et al. ASH 2017

Molecular Relapse-free Survival (%) Molecular Relapse-free Survival Molecular Relapse-free Survival in All Enrolled Patients (N = 84) 10 0 80 60 40 20 0 49% (38.0, 59.4) Estimated survival 95% confidence band 0 4 8 12 16 20 24 28 32 36 Patients at Months Since Dasatinib Discontinuation risk 84 61 44 39 31 27 22 15 15 5 Patients on first-line dasatinib (n = 37) Patients on subsequent lines of dasatinib (n = 47) Resistant (n = 25) Intolerant (n = 18) MRFS, % (95% CI) 54 (38.0, 70.1) 45 (30.2, 58.7) 44 (24.5, 63.5) 50 (26.9, 73.1) No patients lost CCyR or CHR; no transformation events or deaths were observed CI = confidence interval; CCyR = complete cytogenetic response; CHR = complete hematologic response; MMR = major molecular response; MRFS = molecular relapse-free survival. 32 Shah et al. ASH 2017

Which outcome for the patients who have to restart the TKI therapy?

Patients who regained MR 4.5, % Patients who regained MR 4.5, % Patients who regained MMR, % Patients who regained MR 4, % Rates of molecular response regained a 100 90 80 70 60 50 40 30 20 10 Cumulative n/n Cumulative % 0 0 0/86 0.0 ENESTfreedom 6 12 18 24 Time since start of retreatment, weeks 40/86 46.5 79/86 91.9 85 of 86 patients (98.8%) regained MMR 50% at 7.9 weeks 83/86 96.5 84/86 97.7 30 85/86 98.8 100 90 80 70 60 50 40 30 20 10 0 Cumulative n/n Cumulative % ENESTop 48 of 51 patients (94.1%) regained MR 4 50% at 12.0 weeks 0 6 12 18 24 30 36 42 48 Time since start of retreatment, weeks 0/51 0.0 6/51 11.8 26/51 51.0 46/51 90.2 47/51 92.2 47/51 92.2 47/51 92.2 47/51 92.2 48/51 94.1 100 90 80 70 60 50 40 30 20 10 0 76 of 86 patients (88.4%) regained MR 4.5 50% at 15.0 weeks 0 6 12 18 24 30 36 42 Time since start of retreatment, weeks 48 54 100 90 80 70 60 50 40 30 20 10 0 47 of 51 patients (92.2%) regained MR 4.5 50% at 13.1 weeks 0 6 12 18 24 30 36 42 48 Time since start of retreatment, weeks Cumulative n/n Cumulative % 0/86 0.0 0/86 0.0 21/86 24.4 64/86 74.4 71/86 82.6 72/86 83.7 74/86 86.0 75/86 87.2 75/86 87.2 76/86 88.4 Cumulative n/n Cumulative % 0/51 0.0 2/51 3.9 15/51 29.4 39/51 76.5 44/51 86.3 47/51 92.2 47/51 92.2 47/51 92.2 47/51 92.2 a Cumulative rates of molecular response regained following treatment reinitiation.

Patients Who Lost MMR and Restarted Dasatinib (n = 43) Kinetics of Loss and Recovery of MMR and MR 4.5 MMR Loss of MMR Lost to follow-up Restart treatment Recovery of MR 4.5 Ongoing Patients Who Lost MMR (n = 44) Median time from discontinuation to loss of MMR, months (range) 3.93 (1.1-15.6) Patients who lost MMR and restarted treatment, n (%) 43 (98) a Patients evaluated for molecular response after restarting dasatinib, n (%) Patients who regained MMR Patients who regained MR 4.5 42 (95) b 42 (100) 38 (90) Median time to regain MMR, months (range) 1.89 (0.9-3.7) 0 3 6 9 12 15 18 Median time to regain MR 4.5, months 21 (range) 24 27 30 33 36 3.25 39 (1.9-14.7) 42 Months All evaluable patients regained MMR a median of 1.9 months after restarting dasatinib a One patient lost MMR and had not restarted therapy prior to data cut. b One patient lost MMR and restarted treatment. They discontinued the study after only 1 follow-up PCR assessment. MMR = major molecular response; MR 4.5 = molecular response with 4.5-log reduction of BCR-ABL1 transcripts; PCR = polymerase chain reaction. 35 Shah et al. ASH 2017

TFR probability (%) 100 75 Treatment-free remission Median follow-up 39 months (5 116) 65.19% [95% CI 54.85 77.46] at 6 months 48.69% [95% CI 38.13 62.18] at 12 months 40.61% [95% CI 30.32 54.39] at 24 months 33.24% [95% CI 22.91 48.22] at 36 months To have to restart the therapy is not a definitive failure for TFR 50 25 Some patients are simply not yet ready for TFR and they should continue therapy for another while and consider TFR at a later date 0 Numbers at risk New investigational approaches are needed for these patients 0 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 Time since TKI discontinuation (months) 69 44 32 27 21 18 12 8 6 5 4 3 3 2 2 2 2 1 1 1 Legros L et al. Blood (ASH) 2016;Abstract 788.

To restart the TKI therapy is it better to do it with the same or with another TKI (more potent like second generation TKI or ponatinib)?

Are we ready to introduce TFR in in clinical practice? Data from an observational Study in Adult CML Patients who discontinued TKI in Italy

Reasons for discontinuation (N=208): Toxicity 28% (60) Pregnancy 10% (24) Pt request 56% (116) Carmen Fava et al., submitted

MR at discontinuation (N=184): MR3 8% (14) MR4 30% (56) MR4.5 36% (67) 92% MR5 26% (47) 62%

Retrospective analysis of Italian patients who discontinued TKIs No specific monitoring rules (generally monitored more frequently than usual, but not every month) Reasons of Re- Treatment Loss of MR4, n (%) 21 (17) After the restart of the treatment all patients achieved again at least MMR Loss of MMR, n (%) 84 (70) Loss of CCyR, n (%) 9 (7) Other, n (%) 7 (6) No progressions were observed Expected TFR at 12 months 69% No progressions

Conclusion TFR can be already introduced in our every day clinical practice for CML patients, but. with a little bit of good sense!

Grazie Thank you