Calquence (acalabrutinib) is a targeted cancer medication used to treat two types of blood cancer: chronic lymphocytic leukemia (CLL), including its close variant small lymphocytic lymphoma (SLL), and mantle cell lymphoma (MCL). It works by blocking a specific protein that cancer cells need to grow and survive, and it’s taken as a pill rather than given through infusion.
How Calquence Works
B cells are a type of white blood cell that normally helps your immune system fight infections. In CLL, SLL, and MCL, these B cells become cancerous and multiply uncontrollably. They rely on a protein called Bruton’s tyrosine kinase (BTK) to receive the growth signals that keep them alive and dividing.
Calquence permanently attaches to BTK and shuts it down. Without those growth signals, the cancerous B cells stop multiplying and eventually die off. What sets Calquence apart from older drugs in the same class is its selectivity. It targets BTK with minimal effects on other proteins in the body, which translates to fewer off-target side effects.
Chronic Lymphocytic Leukemia and SLL
CLL is the most common type of leukemia in adults, and SLL is essentially the same disease but concentrated in the lymph nodes rather than the blood. Calquence is approved for both newly diagnosed patients and those whose cancer has returned after previous treatment or stopped responding to it.
Calquence can be used on its own or in combination with other cancer therapies. The FDA approved a combination of Calquence with venetoclax (a different targeted therapy) for CLL/SLL based on results from the AMPLIFY trial, which showed that patients on the combination went significantly longer without their disease progressing compared to those receiving standard chemotherapy-based regimens. At a median follow-up of about 42.6 months, the combination group hadn’t yet reached a median progression-free survival, while the chemotherapy group’s median was 47.6 months, representing a 35% reduction in the risk of disease progression or death.
In head-to-head comparison with ibrutinib, the first BTK inhibitor on the market, Calquence matched it in effectiveness. Both drugs delivered a median progression-free survival of 38.4 months after about 41 months of follow-up. The key difference was safety: Calquence caused significantly less atrial fibrillation (9.4% vs. 16.0%), and fewer patients stopped treatment due to side effects (14.7% vs. 21.3%).
Mantle Cell Lymphoma
MCL is a rarer and often aggressive form of non-Hodgkin lymphoma. Calquence is approved for adults with MCL, including those whose cancer has come back or hasn’t responded to prior treatment. In a clinical trial of 124 patients with relapsed or refractory MCL, 81% responded to Calquence, and 40% achieved a complete response, meaning no detectable cancer remained on imaging. After 12 months, 72% of responders were still in remission.
Common Side Effects
The four most frequently reported side effects across clinical trials are upper respiratory tract infections, diarrhea, headache, and musculoskeletal pain, each occurring in 30% or more of patients. Most of these are mild to moderate. In CLL trials, about 35% of patients experienced headaches and diarrhea, while roughly a third reported muscle or joint pain.
Other common side effects include:
- Fatigue: reported by 15% to 37% of patients depending on the trial
- Rash: 16% to 47%, more common in MCL patients
- Bruising: around 17% to 21%
- Infections: 56% to 65% experienced some form of infection in CLL trials, though most were mild upper respiratory infections
Blood count changes are also common. Low white blood cell counts (which can increase infection risk) and low platelet counts (which can increase bleeding risk) affect a significant number of patients and require regular blood monitoring throughout treatment.
Heart Rhythm and Bleeding Risks
BTK inhibitors as a class carry a risk of atrial fibrillation, an irregular heart rhythm that can cause palpitations, dizziness, or shortness of breath. In a pooled analysis of 762 patients taking Calquence, atrial fibrillation or flutter occurred in about 5% of patients. This rate is notably lower than what’s seen with ibrutinib, where it runs closer to 16%.
Bleeding is another risk to be aware of. Calquence can affect how your platelets work, which means bruising happens more easily and bleeding may take longer to stop. Among patients who started blood thinners during treatment, about 4% experienced a major bleeding event. If you’re already taking blood thinners or need surgery, your care team will weigh those factors carefully.
How It’s Taken
Calquence is taken by mouth as a 100 mg dose twice daily, roughly 12 hours apart. It’s available in both capsule and tablet form. The tablet version is a practical improvement because the original capsules couldn’t be taken with proton pump inhibitors (common heartburn medications like omeprazole). The tablet doesn’t have that restriction, since studies showed no meaningful change in drug absorption when taken alongside acid-reducing medications.
Treatment continues for as long as the cancer responds and side effects remain manageable. For CLL/SLL, that often means years of continuous therapy. The medication can be taken with or without food, and the tablets should be swallowed whole.
How Calquence Compares to Ibrutinib
Ibrutinib was the first BTK inhibitor approved for blood cancers, and Calquence was designed to improve on it. Both drugs block the same protein, but ibrutinib also hits several other proteins in the body, which contributes to side effects like heart rhythm problems, high blood pressure, and joint pain.
The ELEVATE-RR trial directly compared the two drugs in previously treated CLL patients. Cancer control was identical, with both achieving a median progression-free survival of 38.4 months. But Calquence came with meaningfully fewer cardiovascular side effects and a lower rate of treatment discontinuation due to adverse events. Serious infections and rates of cancer transformation were comparable between the two drugs. For many patients, these safety advantages make Calquence the preferred choice in the BTK inhibitor class.