Table 1.

Baseline and follow-up clinical and hematologic characteristics of the whole cohort of 281 patients with CALRm ET and after stratification in CALR-high and CALR-low, based on the ≥60% threshold level of VAF, as determined by ROC analysis using MFS as the main end point

VariablesCALRm (n = 281)CALR-high (n = 21)CALR-low (n = 260)P (high vs low)
Age at diagnosis, y (range) 53.6 (18-86) 52.4 (27-79) 53.7 (18-86) .80 
Male sex (%) 145 (51.6) 11 (52.4) 134 (51.5) .94 
CALRm type    .008 
Type 1/like 152 (54.0) 11 (52.4) 141 (54.2)  
Type 2/like 101 (36.0) 4 (19.0) 97 (37.3)  
Indeterminate 28 (10.0) 6 (28.6) 22 (8.5)  
CALRm VAF % (mean ± SD) 40.9 (+15.4) 72.2 (9.1) 38.5 (+12.9) .001 
Presence of at least an additional myeloid variant (n = 99) 34 (34.7) 8 (66.7) 26 (30.2) .013 
History of thrombosis  17 (6.0) 3 (14.3) 14 (5.4) .10 
History of bleeding (n = 205) 4 (2.0) 1 (5.6) 3 (1.6) .25 
Leukocytes (×109/L)  7.8 (2.4-17.3) 9.0 (4.4-17.3) 7.8 (2.4-13.2) .17 
Hemoglobin (g/dL)  13.5 (8.4-16.4)  12.8 (8.4-14.0)  13.6 (10.1-16.4) .019 
Hematocrit (%)  41.4 (26-4-49.2) 37.4 (26.5-46.7) 41.6 (29.6-49.2) .012 
Platelets (×1012/L)  817 (460-2851) 789 (527-1729) 817 (460-2815) .93 
BM fibrosis grade 1  39 (13.9) 3 (14.3) 36 (13.8) .81 
Constitutional symptoms  15 (5.3) 1 (4.8) 14 (5.0) .77 
Microvascular symptoms  79 (28.1) 8 (38.0) 71 (27.3) .38 
Splenomegaly  23 (8.2) 3 (14.3) 20 (7.8) .19 
IPSET-rev thrombosis, n (%)     
Very low 113 (40.2) 7 (33.3) 106 (40.8)  
Low 8 (2.8) 1 (4.8) 7 (2.7) .53 
Intermediate 140 (49.8) 10 (47.6) 130 (50)  
High 20 (7.2) 3 (14.3) 17 (6.5)  
IPSET survival (n = 245), n (%)     
Low 135 (55.1) 7 (50.0) 128 (55.4)  
Intermediate 94 (38.4) 4 (28.6) 90 (39.0) .07 
High 16 (6.5) 3 (21.4) 13 (5.6)  
Events during follow-up     
Anemia in FU (n = 193) 41 (21.8) 9 (69.2) 33 (18.3) <.001 
Leukoerythroblastosis in FU (n = 180) 19 (10.6) 6 (46.2) 13 (7.8) <.001 
Splenomegaly in FU (n = 184) 26 (14.1) 5 (50.0) 21 (12.1) <.001 
Symptoms in FU (n = 195) 14 (7.2) 1 (9.1) 13 (7.1) .80 
Thrombosis in FU 28 (10.0) 1 (4.8) 27 (10.4) .41 
Bleeding episodes in FU  13 (6.4) 2 (15.4) 11 (5.8) .17 
Progression to PET MF  50 (17.8) 11 (52.4) 39 (15.0) <.001 
BP  2 (0.7) 0 (0.0) 2 (0.8) .69 
VariablesCALRm (n = 281)CALR-high (n = 21)CALR-low (n = 260)P (high vs low)
Age at diagnosis, y (range) 53.6 (18-86) 52.4 (27-79) 53.7 (18-86) .80 
Male sex (%) 145 (51.6) 11 (52.4) 134 (51.5) .94 
CALRm type    .008 
Type 1/like 152 (54.0) 11 (52.4) 141 (54.2)  
Type 2/like 101 (36.0) 4 (19.0) 97 (37.3)  
Indeterminate 28 (10.0) 6 (28.6) 22 (8.5)  
CALRm VAF % (mean ± SD) 40.9 (+15.4) 72.2 (9.1) 38.5 (+12.9) .001 
Presence of at least an additional myeloid variant (n = 99) 34 (34.7) 8 (66.7) 26 (30.2) .013 
History of thrombosis  17 (6.0) 3 (14.3) 14 (5.4) .10 
History of bleeding (n = 205) 4 (2.0) 1 (5.6) 3 (1.6) .25 
Leukocytes (×109/L)  7.8 (2.4-17.3) 9.0 (4.4-17.3) 7.8 (2.4-13.2) .17 
Hemoglobin (g/dL)  13.5 (8.4-16.4)  12.8 (8.4-14.0)  13.6 (10.1-16.4) .019 
Hematocrit (%)  41.4 (26-4-49.2) 37.4 (26.5-46.7) 41.6 (29.6-49.2) .012 
Platelets (×1012/L)  817 (460-2851) 789 (527-1729) 817 (460-2815) .93 
BM fibrosis grade 1  39 (13.9) 3 (14.3) 36 (13.8) .81 
Constitutional symptoms  15 (5.3) 1 (4.8) 14 (5.0) .77 
Microvascular symptoms  79 (28.1) 8 (38.0) 71 (27.3) .38 
Splenomegaly  23 (8.2) 3 (14.3) 20 (7.8) .19 
IPSET-rev thrombosis, n (%)     
Very low 113 (40.2) 7 (33.3) 106 (40.8)  
Low 8 (2.8) 1 (4.8) 7 (2.7) .53 
Intermediate 140 (49.8) 10 (47.6) 130 (50)  
High 20 (7.2) 3 (14.3) 17 (6.5)  
IPSET survival (n = 245), n (%)     
Low 135 (55.1) 7 (50.0) 128 (55.4)  
Intermediate 94 (38.4) 4 (28.6) 90 (39.0) .07 
High 16 (6.5) 3 (21.4) 13 (5.6)  
Events during follow-up     
Anemia in FU (n = 193) 41 (21.8) 9 (69.2) 33 (18.3) <.001 
Leukoerythroblastosis in FU (n = 180) 19 (10.6) 6 (46.2) 13 (7.8) <.001 
Splenomegaly in FU (n = 184) 26 (14.1) 5 (50.0) 21 (12.1) <.001 
Symptoms in FU (n = 195) 14 (7.2) 1 (9.1) 13 (7.1) .80 
Thrombosis in FU 28 (10.0) 1 (4.8) 27 (10.4) .41 
Bleeding episodes in FU  13 (6.4) 2 (15.4) 11 (5.8) .17 
Progression to PET MF  50 (17.8) 11 (52.4) 39 (15.0) <.001 
BP  2 (0.7) 0 (0.0) 2 (0.8) .69 

Anemia in FU, development of stable hemoglobin <10 g/dL in the absence of bleeding or any other identifiable causes of anemia; BM, bone marrow; Dx, diagnosis; FU, follow-up; Leukocytosis in FU, appearance of stable count >15 109/L leukocytes in the absence of any other identifiable causes of leukocytosis; Thrombocytopenia in FU, development of stable <100 × 1012/L platelets in the absence of any other identifiable causes of thrombocytopenia; Leukoerythroblastosis in FU, appearance of a diagnostic leucoerythroblastic picture; SD, standard deviation; Splenomegaly in FU means, appearance of a palpable spleen of >5 cm from left costal margin in patients without splenomegaly at dx, or a >50% increase in palpable spleen from dx; Symptoms in FU, appearance of constitutional symptoms (weight loss, night sweats, not-infectious fever) in patients without symptoms at dx. Values in bold indicate statistical significance.

Median (range).

n (%).

One patient in CALR-1 and 2 patients in CALR-2 presented hemoglobin level <10 g/dL owing to known thalassemic trait; after exclusion of these patients, the median hemoglobin level in the population resulted was 13.5 g/dL (10.5-16.4).

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