From the Guidelines
Hydroxyurea can reduce bone marrow blasts in some hematologic conditions, though its effect varies by disease type, and it is most effective in reducing elevated blood counts by suppressing bone marrow activity in myeloproliferative neoplasms like polycythemia vera and essential thrombocythemia. In these conditions, hydroxyurea effectively reduces elevated blood counts, but typically doesn't significantly reduce blast percentages 1. The medication works by inhibiting DNA synthesis through ribonucleotide reductase inhibition, causing cell cycle arrest primarily in rapidly dividing cells. Some key points to consider when using hydroxyurea include:
- Typical dosing ranges from 500-3000 mg daily depending on the condition and patient response, with dose adjustments based on blood counts 1.
- Regular complete blood count monitoring is essential during treatment, and hydroxyurea should be used under hematology supervision as part of a comprehensive treatment plan rather than as standalone therapy for blast reduction.
- In chronic myeloid leukemia, hydroxyurea can temporarily lower blast counts but doesn't provide cytogenetic remission 1.
- For acute myeloid leukemia, hydroxyurea is sometimes used temporarily for cytoreduction before definitive therapy, potentially reducing peripheral blasts, but it's not curative and doesn't eliminate bone marrow disease.
- Hydroxyurea is the drug of choice to control cell proliferation and to reduce organomegaly in patients with myeloproliferative-type chronic myelomonocytic leukemia with a low number of blasts (<10%) 1. It's also important to note that the effect of hydroxyurea on bone marrow blasts can vary depending on the specific disease type and patient response, and it should be used as part of a comprehensive treatment plan under the supervision of a hematologist.
From the FDA Drug Label
Hydroxyurea causes severe myelosuppression. Treatment with hydroxyurea should not be initiated if bone marrow function is markedly depressed. Bone marrow suppression may occur, and leukopenia is generally its first and most common manifestation. Thrombocytopenia and anemia occur less often and are seldom seen without a preceding leukopenia Bone marrow depression is more likely in patients who have previously received radiotherapy or cytotoxic cancer chemotherapeutic agents; use hydroxyurea cautiously in such patients.
Hydroxyurea affects bone marrow blasts by causing myelosuppression, which can lead to leukopenia, thrombocytopenia, and anemia. The drug can depress bone marrow function, and its use should be cautious in patients with previous radiotherapy or cytotoxic cancer chemotherapy. 2
From the Research
Effect of Hydroxyurea on Bone Marrow Blasts
- Hydroxyurea has been shown to reduce peripheral leukocyte and blast counts in patients with chronic granulocytic leukemia 3.
- The drug was successful in reducing splenomegaly in 13 of 17 patients and achieved rapid reduction of an elevated blast cell count in nine patients who presented in blastic crisis 3.
- Hydroxyurea acts by causing bone marrow depression, resulting in a decrease in platelet and leukocyte counts 4.
- High-dose hydroxyurea has been used in autologous bone marrow transplantation and has shown promise in treating large cell lymphoma and metastatic breast cancer 5.
- However, hydroxyurea has also been associated with rare side effects such as hemolytic anemia, which has been reported in a few cases 4, 6.
- The effects of hydroxyurea on red blood cell geometry and deformability have also been studied, and it has been found to produce fetal-like red blood cells that are large in size 7.