State and territory health systems are footing the bill for an expensive PBS-listed leukemia medicine because of the need to keep patients admitted after administration, hospital pharmacists have warned.

They are calling for a revamp of the PBS rules for the monoclonal antibody blinatumomab (Blincyto), used to treat positive B-cell acute lymphoblastic leukaemia (ALL).

As with most PBS listings, federal funding is generally only available for outpatients, with the states covering the full cost for any patient receiving a script in public hospital.

However, the listing for blinatumomab also includes strict criteria which say patients must be hospitalised for nine days during the first cycle of treatment due to the risk of cytokine release syndrome.

Under the PBS rules, hospitalisation for two days is also required during the second cycle.

The problem is that many patients end up requiring extra time in hospital because of medication-related adverse events, according to pharmacists at Fiona Stanley Hospital in Perth.

They say that of 12 recent cycles at the hospital, only three met the time criteria, while four patients were admitted for longer stays due to adverse events.

In five cases the patients were released from hospital earlier than the PBS-required stay, mostly because the patients were well, they wrote in Australian Health Review.

One patient was also discharged against medical advice, while two were not hospitalised at all because they received the cycle as an outpatient, the hospital pharmacists added.

Overall, just 20% of the total therapy cost ended up being covered by the PBS across all 12 cycles, with the hospital and state government covering the $117,000 difference, they noted.

“Several patients developed neurotoxicity, including one who required transfer to intensive care and rigorous monitoring with subsequent cycles,” the authors said.

They pointed out this adverse effect had been foreseen by blinatumomab’s sponsor Amgen which had requested a public hospital inpatient supply subsidy in their submission to the Pharmaceutical Benefits Advisory Committee (PBAC) for PBS listing.

However, this had been refused to avoid setting a precedent for PBS funding of inpatient chemotherapy, they said.

“The conflict between federal versus state funding is not limited to blinatumomab,” they added.

“Situations have occurred where patients admitted to hospital or their families have requested outpatient PBS prescriptions to be written and dispensed in the  community and administered to them during their hospital admission.

“This raises complex questions for the hospital clinician as to how to best provide patient care versus abiding by PBS requirements.”

Funding high-cost medications via state and territory health budgets could also result in spending cuts across other areas of the hospital system, they added.

“In the case of blinatumomab, the PBS has not kept pace with medication development, leaving the states  to pick up the shortfall in funding,” the authors concluded.

They suggested allocating additional federal activity-based funding to public hospitals based on the inpatient use of high-cost medicines, along with broader inpatient PBS subsidies where medicine cost was an issue.