How did availability of ibrutinib change the treatment of chronic lymphocytic leukemia?

The study compared treatments in patients with chronic lymphocytic leukemia (CLL), before and after Ibrutinib (Imbruvica) became available in British Columbia, Canada. The authors found that ibrutinib replaced chemoimmunotherapy for treating relapse and improved survival among patients.

Chemoimmunotherapy (CIT) was the traditional upfront therapy for patients with CLL. Upfront therapy is given to previously untreated patients. The drug Ibrutinib later became the recommended therapy for patients with CLL and relapsed CLL. British Columbia approved ibrutinib in 2014 for treating patients with CLL. How treatment patterns changed after it’s approval in the real world (outside of clinical trials) is unclear.

Data of 1729 patients with CLL were analyzed. Patients were divided into 3 groups. 1466 received frontline chemotherapy before ibrutinib’s availability between 1984 and 2014 (group 1). 140 were treated during ibrutinib’s limited access between 2014-2015 (group 2). 123 patients in group 3 received ibrutinib for initial therapy and relapse when it was accessible by state funding (2015-2016).

CIT was given to 51.2% of patients in group 1, 85.7% in group 2 and 68.3% in group 3. The most common CIT was fludarabine (Fludara)–rituximab (Rituxan) or FR. Ibrutinib was given to 1 patient in group 2. 18.7% of group 3 patients received ibrutinib as upfront therapy.

Second-line therapy, which treats relapsed CLL, was CIT-based in 36.1% of patients from group 1. Ibrutinib was given to 33.3% of patients in group 2, while 20.4% received FR. 69.8% of patients in group 3 received ibrutinib as 2^nd-line, while CIT was given to 22.9%.

Overall survival for all patients was 12.4 years on average. Overall survival was improved in groups 2-3 over group 1. The overall survival for group 1 patients was 11.9 years on average while it has not yet been reached in patients from groups 2 and 3.

The study concluded that ibrutinib is the preferred treatment option over CIT to treat relapsed CLL. It also concluded that after ibrutinib's approval in British Columbia, survival improved in patients and transplant is used less as initial therapy.

The study looked back in time to analyze patient data. The number of patients in groups 2 and 3 was much lower compared with group 1.