Acalabrutinib Side Effects and Management

Introduction to Acalabrutinib Side Effects

• The National Comprehensive Cancer Network recommends that patients taking acalabrutinib be monitored for headaches, which occur in 22-51% of patients, and arthralgia/musculoskeletal pain, including back and leg pain, which occurs in 21% of patients 1, 2

Headaches with Acalabrutinib

• Headaches are a common side effect of acalabrutinib, occurring in 22-51% of patients, and are generally self-limited, resolving within 1-2 months of treatment initiation, according to the National Comprehensive Cancer Network 1, 2, 3
• The American College of Physicians may recommend first-line management with acetaminophen (paracetamol) plus caffeine supplements for headaches, which are typically mild to moderate in severity 3, 4

Back and Leg Pain (Arthralgia/Musculoskeletal Pain)

• Arthralgia, which includes back and leg pain, occurs in approximately 21% of patients treated with acalabrutinib, with most complaints being mild to moderate (grade 1-2), as reported by the National Comprehensive Cancer Network 1, 2

Other Common Side Effects to Monitor

• Diarrhea occurs in 52-58% of patients (grade ≥3 in 5%), and nausea occurs in 7-27% of patients, according to the National Comprehensive Cancer Network 1, 2, 4
• Neutropenia (grade ≥3) occurs in 14-19% of patients, thrombocytopenia (grade ≥3) occurs in 7-9% of patients, and anemia (grade ≥3) occurs in 7-15% of patients, as reported by the National Comprehensive Cancer Network 1, 2
• Atrial fibrillation occurs in 4-7% overall (grade ≥3 in 1%), and hypertension occurs in 3-7% overall (grade ≥3 in 2-3%), with acalabrutinib being preferred over ibrutinib in patients with cardiovascular comorbidities due to lower rates of atrial fibrillation and hypertension, according to the European Society of Medical Oncology 3, 5, 6
• The overall bleeding risk is 26-39% for any grade, but only 2% for grade ≥3 bleeding, and patients on antiplatelet or anticoagulant therapies should be monitored, as recommended by the National Comprehensive Cancer Network 3, 4
• The overall infection rate is 65%, with grade ≥3 infections in 14% of patients, according to the National Comprehensive Cancer Network 3, 4

Key Clinical Pitfalls

• The National Comprehensive Cancer Network recommends that patients should not discontinue acalabrutinib prematurely for headaches, as they typically resolve within 1-2 months with conservative management, and patients should be reeducated about adherence when doses are missed due to manageable side effects 3, 4
• The European Society of Medical Oncology recommends monitoring for cardiovascular events (atrial fibrillation, hypertension) even though rates are lower than with ibrutinib, and avoiding concomitant warfarin use, as patients requiring anticoagulation need alternative agents 3, 5, 6, 4

Adverse Events and Management of Calquence (Acalabrutinib)

Common Adverse Events

• Headache is reported in 22‑51 % of patients receiving acalabrutinib, making it the most frequently observed adverse event (NCCN Guidelines, 2020). 7
• Diarrhea occurs in 37‑58 % of patients, with grade ≥ 3 events in only ≈ 5 % (NCCN Guidelines, 2020). 7
• Nausea is experienced by 7‑27 % of patients (NCCN Guidelines, 2020). 7
• Arthralgia (including back and leg pain) is seen in ≈ 21 % of patients, most often grade 1‑2 (NCCN Guidelines, 2020). 7
• Fatigue affects 10‑32 % of patients (NCCN Guidelines, 2020). 7
• Pyrexia (fever) occurs in 12‑21 % of patients (NCCN Guidelines, 2020). 7

Serious Hematologic Toxicities

• Grade 3‑4 neutropenia is observed in 14‑26 % of patients, with grade 4 neutropenia in ≈ 14 % (NCCN Guidelines, 2020). 8
• Grade 3‑4 thrombocytopenia occurs in 7‑10 % of patients (NCCN Guidelines, 2020). 7
• Grade 3‑4 anemia is reported in 7‑15 % of patients (NCCN Guidelines, 2020). 7

Cardiovascular Toxicities

• Atrial fibrillation develops in 4‑7 % of patients overall; grade ≥ 3 events occur in ≈ 1 % (NCCN Guidelines, 2020). 7
• Hypertension is noted in 3‑7 % of patients overall; grade ≥ 3 hypertension occurs in 2‑3 % (NCCN Guidelines, 2020). 7

Bleeding Risks

• Any‑grade bleeding is reported in 26‑39 % of patients (NCCN Guidelines, 2020). 7
• Grade ≥ 3 bleeding occurs in ≈ 2 % of patients (NCCN Guidelines, 2020). 7
• Major hemorrhage (grade ≥ 3 or central‑nervous‑system bleeding) is seen in 3 % of patients, with fatal hemorrhage in 0.1 % (NCCN Guidelines, 2020). 7

Infectious Complications

• Overall infection incidence is ≈ 65 %; grade ≥ 3 infections occur in ≈ 14 % of patients (NCCN Guidelines, 2020). 7
• Upper respiratory tract infections affect 24‑36 % of patients (NCCN Guidelines, 2020). 7

Second Primary Malignancies

• New primary malignancies develop in ≈ 18 % of patients on acalabrutinib (NCCN Guidelines, 2020). 7
• Non‑melanoma skin cancer is the most common second cancer, occurring in ≈ 10 % of patients; other solid tumors account for ≈ 9 % (NCCN Guidelines, 2020). 7
• Hematologic secondary malignancies are observed in ≈ 1 % of patients (NCCN Guidelines, 2020). 7

Hepatotoxicity

• Drug‑induced liver injury (including severe, life‑threatening cases) has been reported with BTK inhibitors such as acalabrutinib (NCCN Guidelines, 2020). 7

Critical Drug Interactions

• Co‑administration of ciprofloxacin markedly increases acalabrutinib plasma concentrations and should be avoided (NCCN Guidelines, 2020). 7
• Azole antifungals inhibit CYP3A4, leading to elevated acalabrutinib levels and heightened toxicity risk (NCCN Guidelines, 2020). 7

Acalabrutinib‑Associated Hematologic Toxicity and Clinical Outcomes

Hematologic Toxicity

• In patients receiving acalabrutinib + obinutuzumab, grade ≥ 3 neutropenia occurs in approximately 30 %, compared with 10 % for acalabrutinib monotherapy, indicating a markedly higher neutropenia risk with the combination regimen. 9

Therapeutic Efficacy in Chronic Lymphocytic Leukemia

• The NCCN guidelines report overall response rates of 81 %–94 % for acalabrutinib in chronic lymphocytic leukemia/small lymphocytic lymphoma, reflecting its primary therapeutic effect of reducing malignant lymphocyte burden. 10

Infection Risk

• Across treated populations, the overall incidence of infections while on acalabrutinib is about 65 %, with grade ≥ 3 infections occurring in 14 % of patients; this heightened risk is attributable both to drug‑induced neutropenia and the underlying immunosuppression of CLL. 11