How Scemblix Works for Chronic Myeloid Leukemia

Medically Reviewed by Shawn Bookwalter, MS, PharmD, BCPS on August 17, 2024
Written by Dena Westphalen, PharmD
6 min read

Chronic myeloid leukemia (CML) is a type of blood cancer. CML is Philadelphia chromosome-positive (Ph+) when pieces of chromosomes 9 and 22 break off and swap places. This creates a new abnormal chromosome that is known as the Philadelphia chromosome. The Philadelphia chromosome causes leukemia by affecting your normal bone marrow and causing changes in your white blood cells. 

Scemblix is usually used to treat Ph+ CML that is in the chronic phase and that has been treated with at least two medicines called tyrosine kinase inhibitors. It can also be used in Ph+ CML that is in the chronic phase and has a specific mutation called the T315I mutation. The chronic phase means it is stable and developing slowly. Your health care provider will help find out what stage your leukemia is based on certain tests on your blood and bone marrow. 

Scemblix is a type of medicine called a tyrosine kinase inhibitor (TKI). This means it is a medicine that works by binding to specific sites on abnormal proteins. When the abnormal Philadelphia chromosome is created, it creates a fusion between two genes that is known as the BCR-ABL1 fusion. This fusion is a protein, and Scemblix works by attaching to the protein and blocking the ABL1 part of the fusion. It treats the leukemia by helping to prevent or limit changes in your bone marrow that lead to abnormal white blood cells.

Scemblix is taken as a tablet that you swallow. You will usually take it once or twice a day without food. It’s important not to eat for at least 2 hours before taking a dose of Scemblix and to not eat for at least 1 hour after taking Scemblix. This is so that the medication can be fully absorbed into your body to treat your leukemia. Scemblix should be taken whole, and you should not crush or chew the tablets. Do not take tablets that are broken, cracked, or damaged, and you should contact your pharmacy about getting damaged tablets replaced.

You should take your Scemblix dose or doses at the same times every day. If you miss your dose and are taking Scemblix once a day and it is less than 12 hours until your next dose, skip the dose and take your next dose as scheduled. If you miss your dose and are taking Scemblix twice a day and it is less than 6 hours until your next dose, skip the dose and take your next dose as scheduled.

You will continue taking Scemblix for as long as possible. This means you will take it until your cancer progresses or you have side effects that make it not safe for you to take. If you have certain side effects, your health care provider may lower or pause your doses of Scemblix. In some cases, they may need to have you stop taking Scemblix completely.

The FDA approved Scemblix for Ph+ CML based on clinical trials that looked at how effective Scemblix was for treating the cancer. 

In the ASCEMBL clinical trial, people who had chronic-phase Ph+ CML that had been previously treated by at least two tyrosine kinase inhibitors (TKIs) took either Scemblix or another TKI called bosutinib. The clinical trial included 233 people, with 157 people taking Scemblix. For this study, 75% of the people were White, 14% were Asian, and 4.3% were Black.

They were followed to see if they had a certain amount of BCR-ABL gene reduced in their blood or bone marrow. This measurement is called the major molecular response (MMR). After 96 weeks of treatment, 37.6% of the people who took Scemblix had an MMR, compared to 15.8% of the people who took bosutinib. This means that about 21.7% more people had an MMR, compared to bosutinib.

This study also looked at the complete cytogenetic response (CCyR), which measures how many cells have Philadelphia chromosomes (Ph) after receiving the medicine. A complete cytogenetic response means there are no cells with Philadelphia chromosomes detected. After 96 weeks of treatment, the CCyR for people who took Scemblix was 39.8%, compared to 16.1% for the people who took bosutinib. This means that Scemblix had about 23.9% more complete cytogenetic responses than bosutinib. 

Scemblix was also studied in people who had chronic-phase Ph+ CML with a T315I mutation in a study called CABL001X2101. It included 45 people who all had the mutation and took Scemblix. For this study, 47% of people were White, 27% were Asian, 2.2% were Black, and about 24% had unreported or unknown races. After 24 weeks of treatment, the MMR in was reached in 42% of people. After 96 weeks, the MMR was reached in 49% of people. 

Scemblix will start working as soon as you start taking the medicine. Your health care provider will do regular bloodwork to monitor how Scemblix is working in your body and treating your cancer. These tests will monitor your blood counts, such as white blood cells, neutrophils, and platelets, so that your health care provider knows that you can continue to take Scemblix safely. If you have certain side effects, such as problems with your pancreas, your health care provider may do more tests to make sure it is safe for you to continue to take Scemblix. 

Side effects are common with medicines that treat cancer, including Scemblix. It is important to tell your health care provider about any side effects you have while you’re taking Scemblix or after. They can help to find out if your side effects are serious or provide more information to help you manage them.

Your health care provider will have you do bloodwork regularly while you’re taking Scemblix. It’s important to go to all of your bloodwork appointments so that your health care provider can make sure Scemblix is safe for you. These tests will make sure you do not have any problems with your blood cell counts that make it unsafe for you to take Scemblix. This is because Scemblix can cause low blood cell counts, such as low platelets (thrombocytopenia), low red blood cells (anemia), and low white blood cells (neutropenia). It can also cause issues with your pancreas, which can sometimes show up in blood tests. If not treated, low blood cell counts can cause serious infections that can be dangerous and even life-threatening. They will also do other tests regularly, like testing your blood pressure to make sure Scemblix is safe for you to continue taking.

You can ask your health care provider what else you can do to prevent or treat common side effects. For example, you can help to prevent and treat nausea and diarrhea by eating bland foods and having multiple small meals throughout the day instead of three large meals. They may also recommend you keep certain over-the-counter medicines on hand to treat common side effects like diarrhea. They will also tell you how to watch for severe side effects, such as shortness of breath and heart problems, and what to do if you have these side effects.

If you have certain side effects while you take Scemblix, your health care provider may need to change your dose of medicine, pause your doses, or even stop your medicine altogether. This will depend on the side effect you have, how severe it is, and what treatment it needs. If your Scemblix dose needs to be lowered, the medicine will continue to work in your body. If your medicine is paused, it is possible that your health care provider will restart the medication at the same dose or at a lower dose once your side effect is treated and gets better.

Scemblix can cause fertility problems in people who were assigned female at birth. You should talk with your health care provider about any goals to have children and the best way to treat your chronic myeloid leukemia. If you are someone who can become pregnant, it is also important that you are not pregnant or do not become pregnant while taking Scemblix and for at least 1 week after your last dose. Your health care provider will talk with you about using effective birth control while you are taking Scemblix. 

The maker of Scemblix has a financial assistance program and may be able to offer coupons or savings for Scemblix.