When chronic lymphocytic leukaemia returns after initially responding to treatment, the journey continues with new therapeutic approaches designed to regain control over the disease and maintain quality of life.

Managing the Journey When CLL Returns

Chronic lymphocytic leukaemia, commonly known as CLL, is a type of blood cancer that affects white blood cells called lymphocytes. When someone has been treated for CLL and the disease comes back, this is called recurrent or relapsed CLL. The main goal of treating recurrent CLL is to control the disease, reduce symptoms, and help people maintain the best possible quality of life^[5]. Unlike many other cancers, CLL is not usually curable, but modern treatments can put it into remission for extended periods, allowing people to live active, fulfilling lives^[5].

Treatment decisions for recurrent CLL depend on several important factors. These include how long the disease stayed in remission after the first treatment, what treatments were used before, how well those previous treatments worked, and the person’s overall health and fitness level^[5][10]. Another critical factor is whether the leukaemia cells have certain genetic changes, particularly a mutation in the TP53 gene or a deletion of part of chromosome 17 (called del(17p)). These genetic features help doctors choose the most effective treatment approach^[11].

It’s important to understand that CLL often progresses slowly. When it comes back, you might not need treatment straight away. Many people experience a gradual relapse without immediate symptoms, and doctors may simply monitor the situation through regular check-ups and blood tests. This approach is sometimes called “watch and wait” or active surveillance^[5][10]. Treatment typically begins when symptoms appear or when the disease shows clear signs of progression that could affect your health.

During the course of CLL, people might experience several relapses over time. Each relapse is numbered – the first time the disease returns is called a first relapse, and if it comes back again, it becomes a second relapse, and so on^[10][19]. With each recurrence, doctors reassess the situation and adjust the treatment plan accordingly. Modern medicine offers an expanding range of treatments, including both standard therapies approved by medical societies and innovative options being tested in clinical trials.

Standard Treatment Approaches for Recurrent CLL

When recurrent CLL requires treatment, doctors have several proven options to choose from. The choice depends on what treatments you’ve had before, how your disease behaves, and your genetic test results. Standard treatments have evolved significantly in recent years, moving away from traditional chemotherapy toward more targeted therapies – drugs that specifically attack cancer cells while causing fewer side effects than older treatments^[10].

One of the most common approaches for recurrent CLL involves drugs called Bruton tyrosine kinase (BTK) inhibitors. These medications work by blocking a specific protein called BTK that cancer cells need to survive and grow. Three BTK inhibitors are commonly used: ibrutinib (brand name Imbruvica), acalabrutinib (Calquence), and zanubrutinib (Brukinsa)^[5][10][11]. These are taken as tablets, usually every day, and treatment continues until it stops working or causes unacceptable side effects. BTK inhibitors have transformed CLL treatment because they can be very effective even in people whose disease has specific genetic changes that make it harder to treat.

Another important targeted therapy is venetoclax (Venclexta), which belongs to a class of drugs called BCL-2 inhibitors. Venetoclax works differently from BTK inhibitors – it helps cancer cells die naturally, a process called apoptosis that normal cells use to eliminate damaged or old cells. Cancer cells have learned to avoid this natural death process, and venetoclax restores it^[5][10][11]. Venetoclax can be given alone or combined with rituximab, an antibody treatment that helps the immune system recognize and destroy cancer cells. This combination is abbreviated as “VR” in medical settings.

For people whose CLL has a TP53 mutation or del(17p), targeted therapies are usually the preferred option because these genetic changes make the disease resistant to traditional chemotherapy^[11]. In these cases, BTK inhibitors or venetoclax-based treatments are typically recommended. For people without these genetic changes, doctors might also consider the combination of idelalisib with rituximab. Idelalisib is a PI3K inhibitor, another type of targeted therapy that blocks a different protein pathway that cancer cells use to survive^[5][10].

Some people might receive chemoimmunotherapy, which combines chemotherapy drugs with antibody treatments. However, this approach has become less common as targeted therapies have proven more effective with fewer side effects^[11]. Chemotherapy works by killing rapidly dividing cells, but it affects both cancer cells and some healthy cells, leading to side effects like fatigue, increased infection risk, nausea, and hair loss.

Treatment is typically given in cycles, with each cycle lasting about 28 days. Some medications are taken daily, while others are given weekly or less frequently^[5][10]. Most people receive treatment as outpatients, meaning you go to the hospital or clinic for treatment but return home the same day. Tablets can be taken at home. After each cycle, your healthcare team checks your blood counts and other measures to see how well the treatment is working and to monitor for side effects. Some treatments involve a fixed number of cycles, typically up to six, while others continue until they stop working or cause problems you can’t tolerate.

Side effects vary depending on which treatment you receive. BTK inhibitors can cause bleeding or bruising problems, joint pain, heart rhythm irregularities, diarrhea, and increased infection risk^[8]. Venetoclax requires careful monitoring when you first start taking it because as cancer cells die rapidly, they can release substances into the blood that might affect kidney function – a condition called tumor lysis syndrome. To prevent this, doctors start with a very low dose and gradually increase it over several weeks while monitoring your blood closely.

In rare cases, particularly for younger people (typically under 70 years old) who are fit enough for intensive treatment and whose disease came back quickly after first-line therapy, doctors might suggest a stem cell transplant^[5][10][11]. This procedure involves receiving high doses of chemotherapy to destroy the cancer cells, followed by an infusion of healthy blood-forming stem cells (either your own collected earlier or from a donor) to rebuild your blood and immune system. Stem cell transplants carry significant risks but offer the possibility of longer remissions for carefully selected patients.

Innovative Treatments Being Studied in Clinical Trials

Beyond standard treatments, researchers are continuously developing and testing new therapies for recurrent CLL in clinical trials. These studies evaluate whether new treatments are safe and effective before they become widely available. Participating in a clinical trial might give you access to cutting-edge therapies that aren’t yet available outside of research settings^[5][10].

Clinical trials proceed through phases. Phase I trials focus primarily on safety – determining the right dose and identifying side effects. These typically involve small numbers of people. Phase II trials test whether the treatment actually works against the disease and continue to monitor safety in a larger group. Phase III trials compare the new treatment directly against current standard treatments to see if it’s better, in even larger groups of people. Only after a treatment successfully completes these phases can it be approved for general use^[2][9].

One promising area of research involves CAR T-cell therapy, a type of immunotherapy that represents a completely different approach to treating CLL^[11]. This innovative treatment takes your own immune cells (T cells) from your blood, modifies them in a laboratory to recognize and attack CLL cells, multiplies them, and then infuses them back into your body. The modified T cells have special receptors on their surface called chimeric antigen receptors (CARs) that help them find and destroy cells carrying specific proteins found on leukaemia cells.

The process of CAR T-cell therapy begins with apheresis, a procedure where your blood is drawn through a machine that separates out the T cells and returns the rest of your blood to you. The collected T cells are then sent to a specialized laboratory where they’re genetically modified to produce CARs. This laboratory process takes several weeks. While your cells are being prepared, you might receive chemotherapy to reduce the number of cancer cells in your body. Once the modified cells are ready, you receive them through an infusion into your vein, similar to a blood transfusion^[11].

CAR T-cell therapy is still considered experimental for CLL and may not be available in every region or country. It’s being studied particularly for people who have already tried multiple other treatments without success. Early research results have shown promise, but this treatment can cause serious side effects, including cytokine release syndrome (when the activated immune cells release substances that cause fever, low blood pressure, and difficulty breathing) and neurological problems like confusion or difficulty speaking. Because of these risks, CAR T-cell therapy requires careful monitoring in specialized medical centers.

Researchers are also testing new combinations of existing targeted therapies. For example, some trials are evaluating whether combining two different types of targeted drugs works better than using either one alone. Others are studying whether shorter, fixed-duration treatments with certain drug combinations can achieve long-lasting remissions, potentially allowing people to have treatment breaks rather than taking medication continuously for years.

Another area of investigation involves drugs with novel mechanisms of action. Scientists are developing medications that target different vulnerabilities in CLL cells. Some experimental drugs aim to interfere with how cancer cells communicate with their surrounding environment in lymph nodes and bone marrow, where they receive survival signals. Others work to overcome resistance mechanisms that allow CLL cells to survive despite targeted therapy.

Clinical trials for recurrent CLL are being conducted in many countries, including the United States, various European nations, and other regions around the world. The location of trials and the specific treatments being tested change over time as research progresses. Many trials specifically recruit people whose CLL has come back after two or more previous treatments^[5][10]. Your medical team can search databases of current trials to find ones that match your situation and are being conducted in locations accessible to you.

Some trials test treatments in people who have specific genetic features. For instance, certain experimental drugs might be designed specifically for CLL with TP53 mutations, while others target disease without these changes. Preliminary results from various trials have shown encouraging signs, such as high rates of disease response (meaning the leukaemia shrinks or becomes undetectable), extended periods before the disease progresses again, and manageable safety profiles. However, these are early results, and longer follow-up is needed to understand the full benefits and long-term effects of these experimental treatments.

Most common treatment methods

• Targeted therapy drugs
  • BTK inhibitors including ibrutinib, acalabrutinib, and zanubrutinib that block a protein cancer cells need to survive
  • BCL-2 inhibitor venetoclax, used alone or combined with rituximab, helps cancer cells die naturally
  • PI3K inhibitor idelalisib combined with rituximab blocks a different survival pathway in cancer cells
  • Most targeted therapies are taken as tablets at home
• Immunotherapy
  • Rituximab is a monoclonal antibody that helps the immune system recognize and destroy cancer cells
  • Often combined with venetoclax or other treatments
  • Given through intravenous infusion
• Chemoimmunotherapy
  • Combines chemotherapy drugs with antibody treatments like rituximab
  • Less commonly used now as targeted therapies have become available
• Watch and wait approach
  • Active monitoring through regular check-ups and blood tests when disease returns slowly without symptoms
  • Treatment starts when symptoms develop or disease shows clear progression
• Stem cell transplant
  • Reserved for younger, fit patients whose disease returned quickly after first treatment
  • Involves high-dose chemotherapy followed by infusion of healthy blood-forming stem cells
  • Not commonly used but considered in carefully selected cases
• CAR T-cell therapy (experimental)
  • Innovative immunotherapy where patient’s own T cells are modified to attack CLL cells
  • Being studied in clinical trials, particularly for people who tried multiple treatments
  • Not available everywhere and requires specialized medical centers