Living with Chronic Myeloid Leukemia (CML)

✅ Tip 2. (Tip 1 is below, it’s basic and inseparably linked with this one, but Tip 2 is even more important) Monitor your response to tyrosine kinase inhibitor (TKI) therapy correctly and on time. Taking imatinib or another TKI regularly is not enough by itself. The goal of treatment is not just to normalize well-being and blood counts, but to achieve a molecular response.

At diagnosis, chronic myeloid leukemia shows 100% of the pathological, chimeric BCR-ABL1 gene. After starting treatment with, for example, imatinib, the amount of this gene begins to decrease.

A significant milestone is a tenfold (1 logarithmic unit, 1 Lg) reduction.

By 3 months, BCR-ABL1 should fall by 1 Lg, i.e., down to 10%.

By 6 months, another 1 Lg, i.e., below 1%.

By 12 months, another 1 Lg from baseline, i.e., below 0.1%.

Thus, during the first year the total reduction should be at least 3 Lg (from 100% down to ≤0.1%).

This reduction to 0.1% or lower is called a Major Molecular Response (MMR). The decrease may be even deeper:

MR4 (4 Lg),

MR4.5 (4.5 Lg),

MR5 (5 Lg).

The key goal: within the first year, reach at least MMR (≥3 Lg reduction) and afterwards maintain that response.

☝️ How often should molecular response be monitored?

Optimal: every 3 months (per ELN 2020 recommendations).

Especially critical during the first year of therapy.

In real life, this may not always be possible, as few certified laboratories report results in International Scale (IS).

If resources are limited, testing at least twice a year is recommended. 👍

✅ Tip 1. Take your TKI regularly (most commonly imatinib is prescribed first-line). Discontinuation should only be done in agreement with your hematologist and is generally possible only in case of serious toxicity. Minor side effects are usually not a reason to stop therapy.

✅ Tip 3. CML is not a disease that contraindicates pregnancy 🤰, but pregnancy must be planned, since TKI therapy must be temporarily discontinued during pregnancy.

Ideally, pregnancy should be planned after achieving a stable MMR or better.

Do not try to hide this and surprise your doctor — your hematologist will likely be understanding and help minimize risks of disease progression.

For men on TKI therapy, although small amounts of the drug may be present in semen, there are no disease-related problems that prevent fatherhood.

CML: Is it possible to stop taking tablets? Side Effects of Dasatinib