Non-Leukemic Chronic Myeloproliferative Disorders                                                                              91

 

14.          Non-Leukemic Chronic Myeloproliferative Disorders

 

14.4.      Polycythemia vera

14.4.1 General considerations

Polycythemia vera (PV) involves a multipotent hematopoietic stem cell and is characterized by an increase in red blood cells, granulocytes and platelets. Erythrocytosis is by far the most prominent clinical manifestation and the cause of its most serious complications like increased risk of thrombosis and abnormal bleeding. Phlebotomy to a hematocrit < 45 %  is the mainstay of treatment for erythrocythemia. The use of a platelet- lowering agent in conjunction with phlebotomy may also be indicated. Cytoreduction with radioactive phosphorus (P32) or alkylating agents is now restricted to patients not younger than 70 years, because of their mutagenicity and leukemogenicity. Newer cytoreductive agents (hydroxyurea, interferon alpha, anagrelide) are increasingly being used but without any clear evidence of superiority. The role of low-dose aspirin as an antithrombotic drug is also under investigation.

 

Transformation of PV into either myelofibrosis with myeloid metaplasia or acute leukemia remains a major problem that may not be influenced by current palliative therapy. Preliminary data provide some evidence, however, that myeloablative therapy with allogeneic hematopoietic stem cell transplantation can be curative in selected patients with advanced PV.

 

Literature:

            BERLIN, Expert Rev. Anticancer Ther, 2 (2002): 330 – 336 (review)

            GILBERT, Semin. Hematol, 38 (Suppl 2): (2001): 25 – 28 (review)

PLATZBECKER et al, Leuk. Lymphoma 43 (2002): 1409 – 1414 (curative therapy with hematopoietic stem cell transplantation)

SPIVAK, Blood 100 (2002): 4272 – 4290 and Br. J. Haematol. 116 (2002): 243 – 254 (review)

            TEFFERI, Leuk. Lymphoma 43 (2002): 1- 7 (review)

 

14.4.2 Hydroxyurea

 Hydroxyurea                        e.g. 25 mg/kg/d  until CR followed by low- dose maintenance

                                              (in patients > 65 years only in case of more rapid recurrence )

 

            Literature :

                        NAJEAN and RAIN, Blood 89 (1997) : 2319 – 2327 and Blood 90 (1997): 3370 –3377

 

 

94                                                                                 Non- Leukemic Chronic Myeloproliferative Disorders 

 

14.4.3 Interferon alpha

Interferon alpha                      initial dose e.g.              3 x 106 IU              3 x weekly

                                                (especially in younger patients < 60 – 65 years)

 

Literature:

            FOA et al, Eur. J. Haematol. 60 (1998): 273-277

            LENGFELDER et al, Ann, Hematol. 79 (2000): 103 – 109

            STASI et al, J. Intern. Med. 242 (1997): 143 – 147

 

14.4.4 Anagrelide

Anagrelide                               initial dose 0.5 mg p.o. 4 times daily or 1.0 mg p.o. 2 times daily.

                                                 Which should be maintained for at least one week. Dosage should

                                                  then be adjusted to maintain platelet count below 600000/ml.

For the reduction of strongly elevated platelet counts. Combination with additional measures to

Control erythropoiesis and granulopoiesis.

 

Literature:

            PETITT et al, Semin. Hematol. 34 (1997): 51 – 54