Chronic Myeloid Leukaemia (CML) Treatment— Behind that small oral tablet meds lies decades of scientific discovery, molecular biology, drug development & clinical research!
Whenever a relatively young patient presents with an elevated white blood cell count, splenomegaly, minimal symptoms, and a blood film showing left-shifted granulocytic maturation, one of the first diagnoses that comes to my mind is Chronic Myeloid Leukaemia (CML).
As a treating haematologist, there is often a sense of relief when the diagnosis is confirmed—not because CML is an insignificant disease, but because modern medicine has transformed its treatment and prognosis. For most patients today, CML can be effectively controlled with oral targeted therapy. Unlike the past, patients do not routinely require prolonged courses of intensive chemotherapy or proceed directly to stem cell transplantation.
In many ways, CML has become a remarkable example of how far medicine has progressed. With good treatment adherence and a sustained deep molecular response, selected patients may even be able to stop their medication under close medical supervision after several years of treatment. This concept, known as treatment-free remission, is something that would have seemed almost unimaginable in the past.
During the first few weeks after diagnosis, one of my most important roles is to reassure the patient. CML is a form of leukaemia, but it is fundamentally different from acute leukaemia. It usually progresses much more slowly and, in the current era, can often be managed with oral medication successfully.
Nevertheless, establishing the diagnosis requires a comprehensive work-up, sometimes comparable in intensity to that performed for acute leukaemia. This includes bone marrow examination where appropriate, together with cytogenetic and molecular studies. The identification of the BCR::ABL1 fusion gene, resulting from the Philadelphia chromosome, is central to confirming the diagnosis.
While awaiting the definitive results, some patients with a very high white blood cell count may require temporary cytoreduction, commonly with hydroxyurea, to bring the blood counts under control. Once CML is confirmed, treatment can then proceed with a tyrosine kinase inhibitor (TKI), which specifically targets the abnormal BCR::ABL1 signalling pathway that drives the disease.
For many patients, this means taking a daily oral medication and attending regular follow-up with a haematologist. Although this is a remarkably convenient treatment compared with what patients with leukaemia may have faced decades ago, the idea of being under specialist care and taking medication indefinitely is not something everyone readily accepts. As a treating physician, I understand that feeling.
I have also witnessed the other side of this story—patients who, for various reasons, were unable to access or receive TKI therapy and subsequently experienced disease progression. Watching CML progress reminds us of what this disease can become when effective treatment is unavailable.
As CML progresses, patients may develop worsening leucocytosis, anaemia, constitutional symptoms, bone pain, bleeding or other complications. In the blast phase, the disease behaves much more aggressively and can resemble acute leukaemia. Seeing patients suffer through advanced disease has made me appreciate, even more deeply, what the discovery of TKIs has given us.
Sometimes, because these medications are so effective and are taken as simple daily tablets, patients may underestimate just how extraordinary they are. A tablet that allows someone with a potentially fatal leukaemia to live a near-normal life can easily become something that is taken for granted.
But behind that small tablet lies decades of scientific discovery, molecular biology, drug development and clinical research.
This is why I consider CML one of the most powerful examples of how technology and scientific discovery can transform human life. We have moved from a disease that once carried a poor prognosis and often required intensive treatment, to one that, for many patients, can be controlled with a targeted oral medication and monitored through highly sensitive molecular testing.
CML is more than just a success story in haematology. It is evidence of what modern medicine can achieve when we understand a disease at its molecular level—and then develop the technology to target it.
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