Ibrutinib for chronic lymphocytic leaukaemia / small lymphocytic lymphoma, October 2020
Page last updated: 16 March 2021
Drug utilisation sub-committee (DUSC)
October 2020
Abstract
Purpose
Analysis of the predicted versus actual utilisation of ibrutinib 24 months following its addition as a streamline authority for the treatment of relapsed or refractory chronic lymphocytic leukaemia (CLL) and relapsed or refractory small lymphocytic lymphoma (SLL).
Date of listing on the Pharmaceutical Benefits Scheme (PBS)
Ibrutinib was listed on the PBS for CLL and SLL on 1 December 2017.
Data Source / methodology
PBS dispensing data for ibrutinib was extracted from the PBS data maintained by the Department of Health, processed by Services Australia. This data was used to establish the number of prevalent and incident patients utilising ibrutinib for relapsing or refractory CLL/SLL and time on therapy.
Key Findings
- Since its listing in December 2017 the utilisation of ibrutinib has increased steadily. Data to June 2020 indicates approximately 1,000 prevalent patients and 40 incident patients are supplied ibrutinib per month.
- In the first year of listing, ibrutinib had 1,435 initiating patients. This is similar to the [REDACTED] patients that was estimated in agreed estimates model. There is a [REDACTED] decrease in incident patients in 2019 compared to year 2 of the estimates model.
- In 2019 the number of initiating patients is substantially less than predicted and due to this expenditure on ibrutinib was less than anticipated.
- Addition of venetoclax onto the PBS in March 2019 was likely to be the cause of reduction in ibrutinib incident patients.
- [REDACTED] The duration of ibrutinib was estimated to be 23.4 months, but median time on treatment was not reached in the first 942 days (~31 months) of PBS data with a mean time on ibrutinib of 21.75 months.
- There were negligible cases detected of ibrutinib use as first line therapy. However there was some evidence to suggest that ibrutinib was potentially being used in combination with rituximab or venetoclax.
- Approximately 68% of incident patients did not have fludarabine in their dispensing history prior to starting ibrutinib, indicating that these patients may not have been suitable for treatment with a purine analogue. The sponsor estimated the number of patients who are not suitable for treatment or retreatment to be [REDACTED]. Since 68% does not include those patients who are not suitable for retreatment then in practice this number could be larger.
- A large portion of patients (19%) move on to treatment with ibrutinib within six months of ceasing their previous line medications and 68% within 42 months. The group of patients starting treatment within six months could potentially be refractory, followed by a consistent amount of potentially relapsing patients in the 7- 42 months group after which the rate of relapsing patients
