Understanding Ph+ ALL

Woman outside.

Not an actual patient

Ph+ ALL is a blood cancer caused by a genetic mutation. This mutation creates an abnormal chromosome known as the Philadelphia (Ph) chromosome. This chromosome produces a blood protein in which two genes—BCR and ABL1—bond together to form BCR-ABL1.

BCR-ABL1 overactivates the bone marrow and causes young white blood cells (called lymphoblasts) to reproduce too quickly. This activity leads to leukemia. 

Sometimes, the Philadelphia chromosome develops new mutations that could be resistant to treatment. 

Treating Ph+ ALL

Tyrosine kinase inhibitors (TKIs) are targeted therapies used to treat Ph+ ALL. They work to inhibit BCR-ABL1 and help stop the rapid spread of lymphoblasts. One way to treat Ph+ ALL in newly diagnosed adults is by using a TKI in combination with chemotherapy. Until now, there was no FDA-approved TKI treatment for use with chemotherapy in adults with newly diagnosed Ph+ ALL.

Monitoring Your Treatment Response

Throughout treatment, your doctor will monitor how well your body is responding. To do this, your doctor may perform 2 types of tests.

  • Cytogenetic testing helps detect the presence of altered chromosomes (such as the Philadelphia chromosome) in the body.
  • Molecular testing measures the levels of BCR-ABL1 in the body. One type of molecular test is called RT-qPCR and it can be used to determine how well treatment is working.

Remission is being redefined in newly diagnosed Ph+ ALL

Today the goal in Ph+ ALL treatment is a deep remission in the bone marrow and disease control.

MRD-negative CR.

MRD stands for minimal residual disease and CR stands for complete remission. Your doctor may call a deep remission an MRD-negative CR.


MRD-negative CR is a more robust response than complete remission. This means that no or very low levels of cancerous blood cells and BCR-ABL1 are detected, even with advanced tests.


When MRD-negative CR is reached, remission of disease is possible.

Why your doctor may change your treatment

Some people will need to change their TKI treatment over time. There are 2 main reasons why a person may need to change their TKI treatment—resistance and/or intolerance.


If your Ph+ ALL no longer responds to a TKI treatment, this is called resistance. A number of factors can cause your cancer to become resistant to treatment, including if your Ph+ ALL develops a mutation. Mutations such as T315I can appear in the BCR-ABL1 protein during treatment with a TKI and may cause your treatment to stop working. 


Another reason for relapse is intolerance to side effects caused by your current TKI. This makes it difficult or not possible to continue taking the treatment.

Mutations may affect treatments

In Ph+ ALL, changes called mutations can appear in the BCR-ABL1 protein during treatment with a TKI. Mutations may impact your condition and cause your treatment to stop working. So, it’s important for your doctor to test regularly for mutations.

If you develop a mutation while on your current TKI, your doctor may recommend that you change to a different TKI that may work better against the mutation.

T315I is a type of mutation that can occur in Ph+ ALL. ICLUSIG is the only TKI that is approved to treat people with Ph+ ALL who have the T315I mutation.

ICLUSIG results in Ph+ ALL

Discover our clinical studies.

How to take ICLUSIG

Learn about dosing in Ph+ ALL.