Constantine S. Tam, MBBS, MD, consulting hematologist and associate professor, Peter MacCallum Cancer Centre, explains findings of his abstract at EHA2022 showing the impact of Australia’s pharmaceuticals benefit scheme on the rise of Bruton tyrosine kinase (BTK) inhibitor prescriptions for the treatment of relapsed/refractory chronic lymphocytic leukemia (R/R CLL), as well as reasons behind the decrease in fludarabine, cyclophosphamide, and rituximab combination therapy usage for first-line CLL.
Public funding for the use of Bruton tyrosine kinase inhibitors (BTKis) in relapsed/refractory chronic lymphocytic leukemia (CLL) contributed to a substantial increase in BTKi prescriptions over a 10-year period in Australia, said Constantine S. Tam, MBBS, MD, consulting hematologist and associate professor, Peter MacCallum Cancer Centre.
Tam served as lead author of a study presented at the 2022 European Hematology Association (EHA) Congress, titled, "Population-Wide Patterns of Care in CLL in Australia: An Analysis of the Pharmaceutical Benefits Scheme Dataset.”
Can you explain the pharmaceuticals benefit scheme (PBS) implemented in Australia and how your analysis was conducted?
So, in Australia, the pharmaceuticals benefit scheme covers drug access for everyone in Australia. We are a publicly funded health system, and PBS is the government authority which dispenses the drug for Australian citizens. So, the PBS data cover the entire Australian population. This is an analysis of 10% of the PBS dispensing for patients with CLL, which gives us a very wide and very unbiased look at the real-world drug use in Australia. We did this over a 10-year period.
Based on findings, what impact would you attribute to PBS for the rise in BTKi prescriptions for relapsed/refractory CLL?
What we showed was that in a 10-year period, that's for relapsed CLL, the rates of BTK use, principally ibrutinib, went from 0% to 62%. Undoubtedly that was due to access. So, the PBS made ibrutinib available free of charge to the patients and that led to a huge explosion in the prescription of ibrutinib. It was also the same period that there was really emerging and firm data that the BTKis are the best drugs to be used in the relapse setting.
So, there's widespread recognition amongst Australian doctors that patients should not be rechallenged with chemotherapy, they should get a novel therapy. And ibrutinib being the first novel therapy to come onto the PBS free of charge for our patients became the most widely used prescription.
Were there any other factors that contributed to the increased adoption of BTKis for CLL?
The other variable would be probably an increase in recognition that chemotherapy is associated with toxicities, especially for older patients. So, at the start of the 10-year period, it was quite common for FCR [fludarabine, cyclophosphamide, and rituximab] to be prescribed to even older patients in Australia. But towards the end of the 10-year period, there was in general a decreased use of FCR in patients over 65, even in the front line, because of increased knowledge and recognition of toxicity in older patients.