Prescribing and usage of medicines for multiple myeloma is mostly consistent with guidelines and PBS restrictions, according to a review by the PBAC’s Drug Utilisation Sub-Committee (DUSC).

The review of PBS data from July 2013 to December 2016 found 9,445 people received 204,947 dispensings for medications.

There was very little co-prescribing (1%) and two thirds of people on monotherapy received bortezomib, about one quarter received thalidomide and the rest received lenalidomide.

However there was some apparent prescribing of lenalidomide as a first line therapy (7%), which was not consistent with guidelines at the time.

“Lenalidomide was subsequently recommended as a first line therapy in the Australian guidelines and listed on the PBS for first line therapy in January 2017.”

Pomalidomide, which was restricted to a third line therapy, was only very occasionally prescribed in the first (0.3%) or second line (0.6%).

Use of lenalidomide was also examined for the indication of myelodysplastic syndrome (MDS) and found to be less than predicted in terms of both patients treated and prescriptions per patient per year.

The DUSC said the lower than expected uptake was likely a result of intolerance, adverse events or a lower than expected benefit in patients with transfusion dependent MDS.

“Breaks in therapy are likely to be associated with toxicity and management of adverse events. Given the older age group and presence of co-morbidities, occurrence of severe adverse events necessitating cessation of treatment for a period of time are highly probable.”

The higher than expected proportion of 5mg versus 10mg capsules being used also suggested the occurrence of adverse events.

The combined non-response plus intolerance rate was shown to be at least 33.8% – greater then predicted in the 2013 submission to PBAC.