Treatment-Free Remission in CML: — Who Can Stop Their TKI?

An undetectable result means the test cannot find the abnormal gene in your blood sample at all — and this is the level you need to reach and hold before TFR becomes a realistic conversation. A single undetectable result does not make you eligible on its own. Per ELN guidance, what matters is sustaining that response consistently across multiple tests over a prolonged period. Ask your oncologist to show you your full PCR history so you can see the trend, not just the most recent number.

European LeukemiaNet guidance specifies minimum durations of sustained deep molecular response and time on TKI before a discontinuation attempt is considered, and the exact criteria depend on which TKI you are taking and your full response history. There is no single universal answer that applies to everyone. The assessment weighs your PCR trajectory over time, how long you have been on treatment, and whether your disease remained in chronic phase throughout. Ask your oncologist to walk you through the specific criteria and where you currently stand against them.

We do not yet have a reliable way to predict in advance who will sustain TFR and who will not. What studies reported to ELN and ESMO show is that a meaningful proportion of carefully selected patients maintain remission for years after stopping, while others see BCR-ABL1 rise within months. The reassuring part is that molecular relapse does not mean the treatment has stopped working — almost all patients who restart regain the same depth of response. Staying off treatment long-term is a realistic outcome for some, not a guarantee for all.

A rise in BCR-ABL1 after stopping is called molecular relapse, and it is the signal to restart your TKI. Because monitoring after stopping is frequent, it is detected early — well before you would have any symptoms. Restarting treatment almost always regains the same depth of remission you had before. Your team will agree a clear threshold with you before you stop, so you know exactly at what level they will ask you to restart. You will never be watching an uncontrolled rise without a plan in place.

Some people experience aching joints and muscles in the weeks to months after stopping — sometimes called TFR syndrome or TKI withdrawal. It is thought to reflect the body adjusting after years on the drug, and it is generally temporary. Others notice nothing unusual at all, or find that certain side effects they had on treatment — fatigue, cramps, skin changes — actually improve after stopping. Tell your team about any new symptom after stopping so they can distinguish TFR syndrome from other causes. Most symptoms settle without specific treatment.

Pregnancy is one of the most important reasons to raise TFR with your oncologist, and that conversation should start well before you plan to try. Most TKIs carry risk to a developing pregnancy and are not considered safe during the first trimester. For women with CML in sustained deep molecular remission, TFR may offer a monitored path that avoids that exposure. The decision involves both your oncologist and a specialist obstetric team. Planning in advance gives the best chance of timing the stop correctly and having a monitoring plan in place before pregnancy begins.