Long-term safety and effectiveness of ibrutinib in patients with chronic lymphocytic leukemia

This study aimed to investigate if first-line ibrutinib treatment was safe and effective in the long-term for patients with chronic lymphocytic leukemia.  

This study concluded that single-agent ibrutinib provided good outcomes for patients when compared to the standard treatment chlorambucil in these patients.  

Chlorambucil (Leukeran) is the standard chemotherapy for patients with chronic lymphocytic leukemia (CLL).  Ibrutinib (Imbruvica) is a targeted therapy that can be used in the treatment of CLL and small lymphocytic lymphoma (SLL).  

It was not known if ibrutinib was safe and effective in the long-term for CLL patients when compared to chlorambucil.  

This study involved 269 patients who had CLL or SLL and were aged 65 years or older. Patients were treated with ibrutinib or chlorambucil. Patients were followed for an average of 60 months.  

Progression-free survival (PFS) at 5 years was 70% for the ibrutinib group compared to 12% for the chlorambucil group. Ibrutinib was associated with an 85% lower risk of disease progression or death compared to chlorambucil. Overall survival (OS) at 5 years was 83% for the ibrutinib group compared to 68% for the chlorambucil group.  

The benefit of ibrutinib could be seen for patients with high prognostic risk (such as TP53 mutation, 11q deletion and/or unmutated IGHV). The overall response rate to ibrutinib was 92% compared to 37% in the chlorambucil group. 30% of ibrutinib-treated patients had a complete response.  

13% of patients experienced neutropenia (low white blood cell levels) as a side effect. 12% of patients experienced pneumonia. Hypertension (high blood pressure) was seen in 8% of patients while anemia (low red blood cell levels) was experienced by 7% of patients. Hyponatremia (low salt level in blood) was seen in 6% of patients.  

The occurrence of side effects and stopping of ibrutinib due to side effects decreased over time. 58% of patients continued to receive ibrutinib. 

This study concluded that single-agent ibrutinib provided good OS and PFS when compared to chlorambucil in patients with CLL. Ibrutinib also provided an increased depth of response over time. 

This study was funded by Pharmacyclics LLC, the manufacturer of ibrutinib.