The most effective treatment of CML is
**Core Concept**
Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the clonal expansion of mature and immature granulocytes due to the BCR-ABL1 fusion gene. The BCR-ABL1 protein is a constitutively active tyrosine kinase that drives the pathogenesis of CML.
**Why the Correct Answer is Right**
The most effective treatment of CML is tyrosine kinase inhibitor (TKI) therapy, which targets the BCR-ABL1 kinase activity. TKIs such as imatinib bind to the ATP-binding site of the BCR-ABL1 protein, inhibiting its kinase activity and thereby suppressing the proliferation of CML cells. Imatinib has been shown to induce complete cytogenetic responses in a significant proportion of patients with CML.
**Why Each Wrong Option is Incorrect**
**Option A:** Other treatments such as interferon-alpha and hydroxyurea may be used in the management of CML, but they are not as effective as TKI therapy in inducing complete cytogenetic responses.
**Option B:** Chemotherapy is not a standard treatment for CML due to its toxicity and limited efficacy.
**Option C:** Bone marrow transplantation may be considered for selected patients with CML, but it is not the most effective treatment option due to the availability of TKIs.
**Clinical Pearl / High-Yield Fact**
The introduction of TKI therapy has revolutionized the treatment of CML, with improved outcomes and increased survival rates for patients with this disease.
**Correct Answer: A. Imatinib.**