Diagnosis according to World Health Organization determines the long-term prognosis in patients with myeloproliferative neoplasms treated with anagrelide: Results of a prospective long-term follow-up

Figures & data

Table 1. Comparison of patient characteristics at study start in patients with ‘true ET’ versus rediagnosed early PMF

Characteristics	ET (n = 21)	PMF (n = 17)	P value
Median age, years (range)	50 (31–72)	50 (27–75)	0.60
Female gender, n (%)	11 (52)	13 (62)	1.0
Median disease duration before study start, months (range)	5 (0–191)	7 (0–145)	0.79
Previous cytoreductive treatment, n (%)	8 (38)	7 (41)	1.00
JAK2 V617F mutated, n (%)	8 (53)	1 (10)	0.04
Hemoglobin, g/l, median (range)	135 (113–162)	130 (89–164)	0.38
Platelets, ×10^9/l, median (range)	842 (601–1336)	1098 (626–1900)	0.05
Leukocyte count, ×10^9/l median (range)	7.2 (3.7–18.0)	7.9 (3.5–17.6)	0.41
Lactate dehydrogenase, μkat/l, median (range)	7.0 (5.3–17.4)	8.8 (5.4–17.4)	0.1

ET, essential thrombocytosis; PMF, primary myelofibrosis.

Figure 1. Reports of deaths and transformations to MDS and WHO-compatible myelofibrosis (%) during at least 7 years of follow-up in relation to new diagnosis after review of bone-marrow specimens. *WHO-compatible overt myelofibrosis; MDS: Myelodysplastic syndrome; ET: Essential thrombocytosis; PMF: primary myelofibrosis.

Table 2. Grade of bone marrow fibrosis in 35 available bone marrow biopsies after at least 7 years of observation

Diagnosis	Grade 0	Grade 1	Grade 2	Grade 3
True ET	12
PMF-0		3	6
PMF-1				1
PMF-2				2
MPN-U	1
PV	5	2	3

ET, essential thrombocytosis; PMF, primary myelofibrosis; MPN-U, myeloproliferative neoplasia-unclassifiable; PV, polycythemia vera.

Contrasting WHO-defined ET, progression of myelofibrosis (at least one grade) is seen in 10 patients with early pre-fibrotic PMF.

Figure 2. Grade 1–4 side effects (WHO grading scale) during the early phase of the study (n = 60) and at 7 years follow-up among patients still treated with anagrelide (n = 26). No grade 4 side effects were recorded at 7 years.

Table 3. Thrombotic and hemorrhagic events during study period in patients with an initial diagnosis of ET and PV

	All (n = 59)	ET (n = 42)	PV (n = 16)
Venous thromboembolism
Deep vein thrombosis	1		1
Pulmonary embolism	1	1
Retinal vein thrombosis	1	1
Arterial thrombosis
Myocardial infarction	2	2
Stroke	8	5	3
Transient ischemic attack	4	4
Other	1	1
Hemorrhage
Intracranial	1		1
Gastrointestinal	2		2
Other	3		3

ET, essential thrombocytosis; PV, polycythemia vera; PMF, primary myelofibrosis.