Switching Treatment


Why Your Doctor May Switch You From GLEEVEC

Although you may be taking GLEEVEC® (imatinib mesylate) tablets for Philadelphia chromosome–positive chronic myeloid leukemia (Ph+ CML), there are reasons why your doctor may switch you to another treatment. Among them:


  • Drug intolerance: While GLEEVEC is designed to target leukemic cells, there are known side effects. If you believe you are experiencing side effects as a result of GLEEVEC, you should talk to your doctor immediately
  • Lack of response: You may not respond to treatment with GLEEVEC
  • Drug resistance: You may lose your response to GLEEVEC over time

What Does Drug Intolerance Mean?

Certain side effects can make it difficult for some people who take medication to stay on treatment. If you can no longer stay on GLEEVEC because of side effects, you may have what is known as "drug intolerance."

Here's important information you should know:


  • Some side effects can go away with time, can be managed with help from your doctor, or can be tolerated
  • Some side effects may be damaging to your health or may be so bothersome they keep you from taking GLEEVEC as prescribed
  • Be sure to tell your doctor or nurse about any side effects you experience while taking GLEEVEC


Do not change your dose of GLEEVEC or stop taking it without talking to your doctor first.


If you can no longer tolerate the side effects of GLEEVEC, talk with your doctor about your treatment options.

Why Do Some People Experience Drug Resistance With GLEEVEC?

Some people who take GLEEVEC for Ph+ CML do not respond to treatment, or lose their response over time. Your doctor may refer to this as "drug resistance" or "imatinib resistance."

Over the course of your treatment, the abnormal protein that tells your body to produce too many white blood (leukemic) cells can change or mutate. When this happens, GLEEVEC can stop working to block the creation of leukemic cells.

Periodic testing will determine if you are reaching your treatment goals. If you stop responding to treatment, you may be resistant to GLEEVEC. That’s why it’s important to discuss the results of your bloodwork with your doctor.

If your doctor determines you are resistant to GLEEVEC, you may be switched to another treatment option.