Analyses of 845 patients with PMF, PET-MF and PPV-MF treated in 35 German hematology centers - A retrospective field study

Background: Primary myelofibrosis (PMF) as well as secondary post essential thrombocythemia (pET)-MF and post polycythemia vera (pPV)-MF are considered rare diseases associated with significant morbidity. Diagnostics and therapeutic options have significantly improved during the last decade by development of novel drugs, improvement of allogeneic stem cell transplantation (SCT) procedures and supportive care. Whereas the characteristics of PMF, pET-MF and pPV-MF patients (pts) participating in clinical trials are well analyzed, data are rare for the general MF population including patients not included in or eligible for clinical trials. Aims: In order to gain a broader, more comprehensive data set on the general MF population we performed a questionnaire poll in 35 German hematology centers gathering characteristics on 845 pts who were currently under care. Methods: A questionnaire asking for general patient and disease specific data as symptoms, splenomegaly, prognostic factors, past/ current treatment and blood count, degree of MF in bone marrow and transfusion frequency was designed. It was distributed to participating centers (n=35, mostly private offices) throughout Germany and analyzed centrally. Time period of collection was 03/2013-12/2015. 845 pts were included i.e. a median of 20 pts (range 6- 90 pts) per center Results: Gender was equally distributed (50%/50%). Pts ages at initial diagnosis were as follows:<50 years (y) (11%), 50-60y (19%), 61-70y (31%), and <70y (40%). Current age was <65y in 70% of all pts. PMF represented the largest MF cohort (77%), followed by pET-MF (10%), pPV-MF (7%) and unspecified (6%). Most pts had a longer disease duration (<5y (36%); 1-5y (48%); <1y (15%); unknown (1%)). Key current blood values at time of survey included abnormal thrombocyte counts (<50GPT/l (6%); 50 to <100GPT/l (10%); ≥450GPT/l (28%) and elevated WBC <25.000/μl (11%). Presence of circulating blasts in the peripheral blood was documented in 11% of pts. Hemoglobin [g/dl] was ≥10 (68%), 8- 10.0 (21%), <8 (8%), unknown for 3% of the pts. Constitutional symptoms were present in 20% of the pts. Common symptoms included splenomegaly (60%), decreased fitness (41%) and weight loss (16%). Pruritus was present in 5% and night sweats in 9% of all pts. An individual Dynamic International Prognostic Scoring System (DIPPS) score was calculable in 495 pts: 19% low risk, 52% intermediate-1, 23% intermediate-2 and 5% high risk disease. Concomitant diseases were common, most often cardiac (56%). Most common medical treatments included cytostatic (37%), anticoagulation (25%), JAK-inhibitors (23%) and none (24%). Non-medical treatments were rare: stem cell transplantation (3%), splenectomy (2%) and spleen irradiation (3%). Only 31% of all pts received red blood cell transfusions, however 7% had received <50 units. Summary/Conclusions: Daily practice MF pts share several characteristics with MF trial cohorts (e.g. COMFORT). As expected the diseases were not as progressed as in the trials. Interestingly gender was equally distributed in our study. SCT was a rarely used treatment within this cohort whereas JAK2 inhibitors were frequently used.