CML Treatment Goals

Chronic myeloid leukemia (CML) typically progresses through three disease phases–chronic, accelerated, and blast crisis–characterized by worsening clinical features and laboratory findings. The immediate goal of treating CML is to stabilize blood counts and achieve hematological and cytogenetic response, thereby avoiding CML progression.

A hematological response (HR) includes reducing white blood counts to normal values, eliminating immature myeloid cells from the peripheral blood, and eradicating the signs and symptoms of disease.

Cytogenetic response is based on analysis of bone-marrow aspirates and the reduction or elimination of Ph+ cells. A complete cytogenetic response (CCR) is defined by the absence of detectable Ph+ cells in bone marrow, and a partial cytogenetic response (PCR) is defined as the presence of 1% to 35% Ph+ cells by standard cytogenetic techniques. Together, complete and partial responses constitute a major cytogenetic response (MCR).¹

Major molecular response (MMR) has been defined as at least a 3 log (1,000-fold) reduction below a standardized baseline derived from a median ratio of Bcr-Abl to Bcr obtained from 30 untreated patients with chronic-phase CML who participated in IRIS.²

Table 1	Parameter	Phase of CML
Typical CML Laboratory Parameters by Phase of Disease		Chronic	Accelerated	Blast
	WBC Count	≥20 x 109/L	—	—
	Blasts	0%	≥10%	≥30%
	Basophils		≥20%	—
	Platelets	or normal	or
	Bone marrow	Myleloid hyperplasia
	Cytogenetics	Ph+
	BCR-ABL	+	+	+

1. Kantarjian H, Sawyers C, Hochhaus A, et al. Hematologic and cytogenetic responses to imatinib mesylate in chronic myelogenous leukemia. N Engl J Med. 2002;346:645-652.
2. Druker BJ, Guilhot F, O’Brien SG, et al. Five-year follow-up of patients receiving imatinib for chronic myeloid leukemia. N Engl J Med. 2006;355:2408-2417.

Next: Glivec^® Side Effect Management