The PBAC’s Drug Utilisation Sub-Committee (DUSC) has determined that usage of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) for stage IV adenocarcinoma of the pancreas is lower than originally predicted.
The review of prescription data from November 2014 to March 2017 found 3,284 patients were supplied the drug since it was PBS-listed for first line treatment of locally advanced, unresectable or metastatic disease, in combination with gemcitabine.
However the number of prescriptions and vials was found to be lower than predicted – possibly related to delays in treatment and dose reductions.
It found about 30% of treatments administered to patients were lower than the initiating dose. About 20% of patients had dose delays longer than 42 days.
“It is likely the dose reductions are due to drug related adverse events, such as neutropenia and thrombocytopenia, as outlined in the PI,” the DUSC report said.
It said dose delays or treatment breaks may be due to drug or disease related adverse events, although it was not possible to determine the reason from the PBS data.
A heavily redacted DUSC report on sunitinib and everolimus for pancreatic neuroendocrine tumours found the number of patients treated between 2009 and 2017 was more than expected but prescriptions per year and overall length of treatment were much less than predicted.
“It is possible that this is a result of a patient selection bias associated with the characteristics of patients taking up treatment soon after listing: the uptake of treatment was in patients with more advanced and potentially more severe disease which leads to shorter duration on therapy than may be seen when less severe patients are treated.”
“There may also be some use in patients with moderately differentiated tumours rather than well differentiated which is outside the eligible population for subsidised treatment,” the report said.