Key takeaways

• BTK inhibitors work by targeting and blocking the BTK enzyme, which is crucial for the survival and growth of cancerous B-cells in mantle cell lymphoma (MCL). This cuts off the cancer cell’s support system, making it vulnerable.
• While traditional treatments like chemoimmunotherapy and stem cell transplants may offer a chance at a functional cure, BTK inhibitors are used as a first-line therapy for specific patients or to manage MCL long-term, especially when intensive treatments aren’t suitable.
• BTK inhibitors can cause side effects by affecting the signaling of healthy B-cells, and first-generation inhibitors carry a higher risk of cardiovascular events, so it’s important for patients to discuss the benefits and risks with their doctor.

Mantle cell lymphoma (MCL) is a type of non-Hodgkin lymphoma. It affects your lymphatic system and develops in the mantle zone of lymph nodes from white blood cells called B lymphocytes.

As a B-cell cancer, MCL causes chronic immune system activation. Not everyone notices symptoms at first, but over time, you may notice nonspecific signs of illness from body-wide inflammation. These symptoms, known as “B symptoms,” can include intermittent fever, weight loss, and drenching night sweats.

Chemotherapy and immunotherapy have long been first-line treatments for MCL, but you might also receive targeted therapies, such as Bruton tyrosine kinase (BTK) inhibitors.

BTK is an enzyme that’s naturally present in your body. In normal B-cells, it helps transmit signals from B-cell receptors that regulate the cell’s chemical production, movement, growth, and survival.

In MCL, the B-cell signaling pathway is dysregulated. It becomes active all the time, which keeps cancerous B-cells alive longer and allows them to grow uncontrollably.

BTK inhibitors block BTK and cut off the cancer cell’s survival pathway. Unlike normal B-cells, which can adapt to changes in BTK by slowing down function and recovering over time, cancerous B-cells can’t adjust as effectively.

Without BTK, they lose the signals keeping them alive and protected. The MCL cells stop multiplying, detach from their micro-environments, and become vulnerable.

When BTK inhibitors were first approved for the treatment of MCL, they were used when other treatments weren’t working (refractory) or when MCL kept returning (relapsing).

This initial focus was because most clinical trials of BTK inhibitors occurred in people who’d already received traditional care. As safety and efficacy evidence grew, researchers expanded the scope of use for BTK inhibitors.

They’re still used for relapsed and refractory situations, but they’re now considered first-line treatments for certain people, such as those with MCL who:

  • are advanced in age
  • live with multiple co-occurring diseases
  • aren’t candidates for chemotherapy
  • show signs of rapidly progressive cancer
  • are not eligible for or decline stem cell transplants

BTK inhibitors have been proven safe and effective for treating MCL in specific people, but they aren’t for everyone.

Your age, overall health, lifestyle, and stage of cancer all influence how MCL is treated. For many younger, fit people, traditional first-line therapies still include:

  • chemoimmunotherapy (chemotherapy plus immunotherapy)
  • stem cell transplant

Chemoimmunotherapy and stem cell transplant are intensive, but they’re preferred options if you’re otherwise fit and healthy since they offer a chance at a functional cure.

While BTK inhibitors have high response rates and can be taken at home, they’re not considered curative because they can leave behind what’s called “minimal residual disease (MRD).” With MDR, there’s a chance of cancer returning if you stop taking the medication.

BTK inhibitors are still used as first-line therapy for certain patients, but they’re primarily used to control MCL long-term, especially when intensive chemoimmunotherapy or transplant isn’t a good fit.

Current BTK inhibitors approved for the treatment of MCL include:

They’re taken by mouth once or twice daily. Most people are instructed to take BTK inhibitors every day until they experience disease progression or medication toxicity.

BTK inhibitors can cause a variety of side effects. Not only do these medications target cancerous B-cells, but they also affect the signaling of healthy B-cells and can cause:

  • fatigue
  • diarrhea
  • nausea
  • headache
  • easy bruising
  • muscle aches
  • increased risk for infection

First-generation BTK inhibitors like ibrutinib are associated with a higher risk of cardiovascular events, such as high blood pressure and irregular heartbeat.

BTK inhibitors offer doctors a way to create highly specialized treatment plans for MCL.

These medications fill in a care gap if you’re not a candidate for traditional therapies or aren’t seeing success with chemoimmunotherapy and stem cell transplant.

BTK inhibitors are less intensive and generally have fewer side effects compared to other treatments. They can be taken at home and can help maintain cancer remission for months or years.

BTK inhibitors aren’t right for everyone living with MCL. To learn more about this treatment option and how it fits into your comprehensive care plan, consider these questions for your doctor:

  • What is a BTK inhibitor, and how does it work for MCL?
  • Am I a candidate for a BTK inhibitor? Why or why not?
  • Which BTK inhibitor would be best for me and why?
  • How will a BTK inhibitor improve my current prognosis?
  • How long will I have to take it?
  • How will I know if it’s working?
  • What side effects are common?
  • What are the signs of a serious adverse reaction?
  • Are there any long-term risks?
  • Does taking a BTK inhibitor eliminate other treatment options in the future?
  • Will my daily routine stay the same?
  • What happens if I miss a dose?
  • How often do I need to come in for medication monitoring?
  • Will my insurance cover it?

BTK inhibitors for MCL target a specific signaling pathway B-cells use to survive. By blocking BTK, these drugs take away the support system MCL needs to grow and spread.

BTK inhibitors can be used as first-line therapy for certain people and are also important for relapsed or refractory MCL, but they aren’t for everyone. If you’re young and fit, chemoimmunotherapy and stem cell transplants are still considered the best options for a functional cure.