From the Guidelines

Filgrastim is the drug of choice for chemotherapy-induced leukopenia (low white blood cell count).

Filgrastim, a granulocyte-colony stimulating factor (G-CSF), is widely used to prevent chemotherapy-induced neutropenia and has FDA approval for this indication 1.
The American Society of Clinical Oncology (ASCO), the American National Comprehensive Cancer Network (NCCN), and the European Organisation for Research and Treatment of Cancer (EORTC) have set-up guidelines for the use of G-CSF in patients receiving chemotherapy to prevent fever and infections 1.
Filgrastim should be given 24-72 h after the administration of myelotoxic chemotherapy and continued until an absolute neutrophil count (ANC) of 10^9/L is reached 1.
The recommended dose of filgrastim is 5 µg/kg/d, and it can be administered subcutaneously 1.
Pegfilgrastim, a pegylated form of filgrastim, is also effective and can be given as a single dose of 6 mg, 24 h after completion of chemotherapy 1.
The use of G-CSF is recommended for primary prophylaxis of febrile neutropenia in patients at high risk (greater than 20%) of developing this condition 1.
Some key considerations for the use of filgrastim include:
- It should not be used in patients without neutropenia suffering from community- or hospital-acquired pneumonitis 1.
- It is contraindicated during radiotherapy to the chest due to increased rate of complications and death 1.
- It should be used with caution in patients with severe thrombocytopenia, as it may exacerbate this condition 1.

From the Research

The treatment for chemotherapy-induced leukopenia can vary, and several options have been studied. Some of the key findings include:

Lithium carbonate has been shown to increase the number of neutrophils and may be an effective treatment for chemotherapy-induced neutropenia and leukopenia 2.
Chinese herbal medicine (CHM) has been found to be effective in improving white blood cell counts and reducing the incidence of neutropenia when used in combination with chemotherapy 3.
Moxibustion, a traditional Chinese medicine technique, has been studied as a potential treatment for chemotherapy-induced leukopenia, with some trials suggesting its effectiveness in increasing white blood cell counts 4.

The drug of choice for chemotherapy-induced leukopenia is not explicitly stated in the provided studies. However, some studies suggest that:

Lithium carbonate may be a potential treatment option for chemotherapy-induced neutropenia and leukopenia 2.
Chinese herbal medicine (CHM) may be used in combination with chemotherapy to improve white blood cell counts and reduce the incidence of neutropenia 3.
Granulocyte colony-stimulating factor (G-CSF) is often used to treat chemotherapy-induced neutropenia, but its effectiveness in treating leukopenia is not clearly established in the provided studies.

Some key findings from the studies include:

Chemotherapy-induced leukopenia is associated with improved recurrence-free or overall survival in breast cancer patients 5.
The degree of leukopenia is highly significantly associated with improved distant disease-free survival and overall survival in breast cancer patients 5.
Lithium therapy can ameliorate chemotherapy-induced leukopenia and neutropenia in breast cancer patients 2.
Chinese herbal medicine (CHM) can effectively improve the clinical symptoms of chemotherapy-induced leukopenia when compared with chemotherapy alone or Western medicine + chemotherapy 3.