Molecular aberrations in MPN. and use in the clinic. Timothy Devos MD PhD

Transcription

1 Molecular aberrations in MPN and use in the clinic Timothy Devos MD PhD MB&C

2 Introduction 1951: William Dameshek MPD MPN = clonal, hematopoietic stem cell disorders, proliferation in BM of one or more myeloid cell lines. similar clinical phenotype 1960: Phi + (CML) and Phi - MPN

3 WHO 2016: MPN Arber et al. Blood 2016

4 POLYCYTHEMIA VERA

5 PV: clinical manifestations thrombosis (art > ven) facial plethora, pruritus (aquagenic) (40%), constitutional Σpt abdominal discomfort (splenomegaly) microvascular disturbances: headaches, erythromelalgia hyperviscosity: dizziness, visual disturbances, headaches Landolfi et al. Leukemia 2008

6 Risk factors: age > 67 yr = 5 pt age yr = 2 pt WBC > /µl = 1 pt venous thrombosis = 1 pt Low R = 0 pt Int R = 1-2 pt High R = 3 pt Tefferi et al. Leukemia 2013

7 PV: risk stratification Low risk - age below 60 years - no history of trombosis - absence of cardiovascular risk factors (DM, smoking, cholesterol, AHT ao.) High risk - age 60 years or older - history of thrombosis

8 PV: management Low risk - flebotomy - low dose ASA ( mg/d if no contra indication) - manage CV risk factors aggressively High risk - flebotomy - low dose ASA ( mg if no C-I) - cytoreductive therapy (HU of IFNα) - manage CV risk factors aggressively target Hct < 0.45

9 ESSENTIAL THROMBOCYTHEMIA

10 ET: epidemiology and symptoms average age at diagnosis: yr incidence: / 10 6 estimated prevalence: 400 / 10 6 F > M (peak F 30 yr) symptoms: - mostly asymptomatic %: thrombosis (art > ven) - microcirculatory disturbances: headache, dizziness, distal paresthesias, acrocyanosis, erythromelalgia - bleeding (cave: BP > /µl) - itching (15 40 %)

11 ET: risk stratification Low risk Intermediate risk - younger < 60 yr - no history of thrombosis - BP < /µl - no clear cut definition (not low, not high) - operational definition : low risk patients with one or more of the following risk factors: CV disease, diabetes, smoking, hypertension, familial thrombophilia, ea. High risk - older > 60 yr - history of thrombo-embolic event(s) - BP > /µl

12 ET: management Low risk low dose ASA (if no contraindication) Intermediate risk low dose ASA treat C-V risk factors aggressively in some patients: BP reduction (decision on individual base) High risk low dose ASA reduce BP to < /µl treat C-V risk factors

13 MYELOFIBROSIS

14 BCR-ABL negative MPN PV 7-8%/10 yr PMF MF ET 4%/10 yr PPV - MF PET - MF

15 MF - clinical presentation symptoms: - fatigue, weight loss, abdominal pain, dyspnoe, itching, bleeding, constitutional symptoms, bone pain, - 33 % asymptomatic clinical examination: splenomegaly hepatomegaly ascites gout arthritis extramedullary hematopoiesis: adenopathy, pleural pericardial effusion, GI of urinary tract, lung, (CNS, skin)

16 reticulin staining MF - diagnosis BM aspirate: frequent dry tap megakaryocytic hyperplasia trephine biopsy: fibrosis (not pathognomonic) osteosclerosis

17 Prognostic score (IPSS PMF) Risk group number of risk factors median survival (years) Low 0 11,3 Intermediate 1 1 7,9 Intermediate High 3 2,3 Risk factors: age > 65 yr Hb < 10 g/dl WBC > 25000/µl peripheral blasts > 1 % consitutional Σpt (weight loss > 10 %, night sweats, unexplained fever) Cervantes et al. Blood 2009

18 (PHENOTYPIC) DRIVER MUTATIONS in MPN

19 V617F JAK2 mutation

20 JAK-STAT SIGNALLING PATHWAY JAK-STAT signalling external signals are transmitted across the cell membrane through cytokine receptors nucleus initiating expression of genes regulating cell growth, differentiation and death. cytokine receptor plasma membrane cytoplasm nucleus Jatiani SS, et al. Genes Cancer 2010; 1:

21 ROLE OF JAK2 SIGNALLING IN PROLIFERATION AND INCREASED SURVIVAL OF MALIGNANT HEMATOPOIETIC CELLS JAK2 V617F or MPL W515 L/K constitutive activation of signalling pathways hypersensitivity to cytokines dysregulation of the JAK-STAT pathway increased survival and proliferation of malignant blood cells MPN Abdel-Wahab OI, et al. Annu Rev Med 2009; 60:

22 JAK2 V617F in MPN 95% 50-60% 55-60% Klampfl T et al. N Engl J Med 2013;369:

23 But.... many questions remain!!! - is JAK2 V617F the initiating mutation ( founding mutation ) in the different MPNs? - interaction between JAK2 V617F mutation and other somatic mutations? - relation between allelic burden and phenotype of MPNs?

24 Breakthrough end CALR mutation

25 CALR mutations in MPN Klampfl T et al. N Engl J Med 2013;369:

26 Calreticulin Is A Major Chaperone Resident in the Endoplasmic Reticulum via KDEL C-Terminal Sequence Molecular Cell Biology Lodish et al., Seventh Edition, W. H. Freeman and Co. New York

27 Functions of Calreticulin Chao Sun et al. Leukemia & Lymphoma 2014

28 CALR Mutations in MPNs Peptide Sequences of the Two Most Common CALR Mutations CALR Exon 9 3'UTR Nonmutant CALR 52-bp Deletion (type 1 mutation) 5-bp Insertion (type 2 mutation) Frequency of the 36 Mutation Types Detected in CALR Types 5 10 (0.7% each) Types (0.3% each) Type 4 (1.0%) Type 3 (1.7% Type 1 (53.0%) Type 2 (31.7%) Adapted from Klampfl T et al. N Engl J Med. 2013;369:

29 CALR mutation in MPN CALR mutants: loss of KDEL retention signal (Cterminus) crucial for pathophysiology in CALR mutants. the megakaryocytic cell line is pathologic in CALR mutants (in ET en MF, not in PV). CALR mutants activation of JAK-STAT pathway pathologic signals in MPN/CALR mutants possibly through effects on calcium metabolism or through aberrant unfolding of cytokine receptors linked to JAK2. Klampfl T et al. N Engl J Med 2013;369: Tefferi et al. Leukemia 2014, Jan 9. Epub ahead of print.

30 W515 MPL mutation

31 W515 MPL MUTATION MPL W515 L/K dysregulation JAK/STAT signal pathway hypersensitivity cytokines (self-activation of TPO-R) Abdel-Wahab OI, et al. Annu Rev Med 2009; 60:

32 EPIGENETIC ( NON-DRIVER ) MUTATIONS

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35 Genotype-Phenotype correlations in Essential Thrombocythemia (ET)

36 CALR ET % JAK2 + Hb BP WBC Thrombosis PET-MF survival age M/F Andrikovics et al. Lower Hb Higher BP Lower WBC Rotunno et al. Lower Hb Higher BP Lower WBC Rumi et al. Lower Hb Higher BP Lower WBC Lower risk venous thrombosis Lower risk thrombosis Lower risk thrombosis More frequent in CALR-ET NS NS younger Trend to more F but NS Trend better survival (NS) younger M > F NS NS younger M > F Klampfl et al. Lower Hb Lower WBC Lower risk thrombosis Better survival CALR+ ET Chich-Cheng Chen et al. Ann Hematol NS Higher BP Lower WBC Lower risk venous thrombosis (longer TFS) NS younger Nangalia et al. Lower Hb Higher BP No difference WBC NS More frequent in CALR-ET NS (remark: small sample size) No influence of age (NS) M =F Chun Qiao et al. Haematologica Gangat et al. Tefferi et al. Leukemia Trifa et al. BJH Lower Hb Higher BP Lower WBC Lower Hb Higher BP Lower WBC Lower Hb Higher BP Lower WBC NS younger M = F Lower risk thrombosis if < 60 yr Less major thrombosis events NS No difference in survival (longest FU! 12 yr!) Trend to younger but NS M > F

37 Lower Hb in CALR+ ET Rumi et al. Blood 2014.

38 Lower WBC in CALR+ ET Rumi et al. Blood 2014.

39 Higher BP in CALR+ ET Rumi et al. Blood 2014.

40 Cumulative Incidence of Thrombosis (%) Lower thrombosis risk in CALR -ET CALR exon 9 mutation JAK2-V617F mutation MPL exon 10 mutation Years The cumulative incidence of thrombosis at 10 yrs was 11.0% (95% CI, 6.3 to 17.1) in CALR mutants versus 21.0% (95% CI, 16.6 to 25.7) in JAK2 mutants (P=0.003). In patients with JAK2 mutated ET, the cumulative incidence of polycythemic transformation was 28.6% (95% CI %) at 15 years. No progression to PV was observed in patients with CALR mutated ET. Adapted from Klampfl T, et al. N Engl J Med. 2013;369: ; Rumi E, et al. Blood. 2014; Dec 24 Epub ahead of print.

41 IPSET thrombosis score Risk group number risk factors (points) thrombosis free survival (TFS) Low (41%) % (after 15 yr) Intermediate (47%) 2 first 10 yr like low risk; next 5 yr more like high risk High (12%) % (after 7 yr) Risk factors: age > 60 yr: 1 point (< 60 yr: 0) CV risk factors: YES 1 point ( no 0) history of thrombo-embolic events: YES 2 points (NO: 0) JAK2 V617F mutation: present 2 points (absent: 0) Barbui et al. Blood 2012

42 Pietra et al. Leukemia 2015

43 Haematologica, April 2015

44 Probability of Survival Myelofibrosis: better survival in CALR + MF CALR exon 9 mutation JAK2-V617F mutation MPL exon 10 mutation Years Adapted from Klampfl T, et al. N Engl J Med. 2013;369:

45 CALR subtypes and MF Contradictory results: * Tefferi et al. (Leukemia 2014): CALR type 1 MF has better prognosis * Cabagnols et al (Leukemia 2015): CALR type 1 MF worse prognosis due to small numbers of patients? What we know for sure: type 2 CALR predominantly associated with ET-phenotype, low thrombosis risk and indolent course type 1 CALR predominantly associated with MF-phenotype and higher risk of progression ET PET-MF

46 Take Home messages V617F JAK2 mutation is associated with a higher thrombosis risk in MPN CALR mutations are selectively associated with JAK2 and MPL unmutated ET or MF. CALR mutations are associated with a different clinical phenotype, both in ET or MF (higher BP, lower Hb, lower WBC, younger). CALR+ ET patients have a lower thrombosis risk compared to JAK2+ ET. A survival benefit has been shown both in CALR+ ET and CALR+ MF.