Ischaemic heart disease

Use of P2Y12 antiplatelets in ACS doesn’t follow evidence: review


Clopidogrel remains the most widely used P2Y12 antiplatelet for treatment of ACS in Australia despite the emergence of newer more potent agents, a study has found.

The review of PBS data for 2010-2020 also found that ticagrelor was very costly while prasugrel had been little used and ultimately withdrawn despite being a lower cost and highly effective alternative P2Y12 option.

The study, published in Heart, Lung and Circulation (link) showed that use of P2Y12 agents had more than doubled in a decade, likely reflecting rising rates of PCI requiring dual antiplatelet therapy (DAPT).

Study author Dr Timothy Abrahams of MonashHeart, Melbourne said it was notable that three-quarters of the $40 million PBS spending on P2Y12 therapy was for ticagrelor, despite it making up just one-quarter of the total prescriptions.

“Whilst we anticipated that ticagrelor would cost more than clopidogrel, we did not realise the massive health care expenditure on ticagrelor,” he said.

He said ticagrelor was 60% more expensive than prasugrel and more than 10 times the cost of clopidogrel.  And while ticagrelor had a MACE absolute risk reduction (ARR) of 1.9% compared to clopidogrel, its higher cost meant that $72,637 was required per MACE prevented by prescribing it instead of clopidogrel.

This made it 1.7 times more costly per MACE prevented than prasugrel, which had an ARR of 2.2% compared to clopidogrel, and which required $42,993 per MACE  prevented  instead of clopidogrel.

The study showed that the volume of P2Y12 scripts written more than doubled between 2010 (403,880 scripts) and 2020 (994,826 scripts). In 2010 almost all scripts were for clopidogrel (98%), but after the approval of ticagrelor in 2012 it achieved 26% of total scripts by 2022.

The now-withdrawn prasugrel was deemed the “most efficacious P2Y12 inhibitor after ACS” but accounted for only a small number of prescriptions.

Dr Abrahams said it appeared that clinicians had reverted to prescribing clopidogrel after prasugrel was no longer available, possibly because of clinician familiarity and patient tolerance.

He postulated that prasugrel was withdrawn from Australia for commercial reasons due to low usage, but noted there may be generic prasugrel products available on the PBS in future, as products were TGA registered in Australia.

“Compared to other health care systems, Australian patients are deprived of a standard therapy that is cheaper and emerging as a more effective agent … European Society of Cardiology guidelines recommended prasugrel should be considered in preference to ticagrelor for Non-ST-segment-elevation ACS patients who proceed to PCI, which can no longer be offered in Australia,” he said.

Meanwhile, total ticagrelor spending continues to rise, reflecting an increase in absolute number of P2Y12 prescriptions in Australia rather than an increase in proportion of total scripts, the paper’s authors noted.

“With time, we anticipate that prescribing trends for P2Y12 inhibitors will transition to model the available evidence, as clinicians become more familiar with ticagrelor and prasugrel becomes available through generic license,” they said.

 

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