PBS change opens door to dual therapy for more patients with PAH


13 Oct 2020

A/Prof Edmund Lau

A change that allows physicians to prescribe dual therapy for patients with pulmonary arterial hypertensions (PAH) on the PBS has been “a long time coming”, says respiratory physician Associate Professor Edmund Lau.

From 1 October, patients with WHO Functional Class III and IV PAH can receive subsidised therapy with both an endothelin receptor antagonist (ERA) and phosphodiesterase-5 (PDE-5) inhibitor – a combination that is considered the standard of care for most patients.

Associate Professor Lau, a respiratory physician at Royal Prince Alfred Hospital in Sydney, said combination therapy with an ERA and PDE-5i had been assigned a high level of recommendation by international guidelines for the majority of PAH patients for more than five years.

However, the lack of a PBS subsidy had meant patients needed to purchase medications on private prescription, rely on compassionate access programs or rely on hospital prescribing to access the combination of drugs.

A recent Australian study found that a significant proportion of patients with PAH remained undertreated on monotherapy. The study of more than 1,000 patients enrolled in the Pulmonary Hypertension Society of Australia and New Zealand Registry found 51% were treated with monotherapy and 49% with combination therapy.

“It [the PBS-listing] is very welcome,” Associate Professor Lau said. “It has been a very long time coming – the evidence for combination therapy has been around for a long, long time.”

Most patients newly diagnosed with PAH would fit the criteria to receive subsidised dual therapy, he said, adding that the PBS requirements around prescribing were consistent with good clinical practice.

Associate Professor Lau said options for treating PAH continued to expand, and he expected other drug combinations would eventually become available on the PBS.

For example, combination therapy using the oral prostacyclin receptor (IP) agonist selexipag may be a future option for patients, he said.

Approximately 420 patients start on a PAH medicine for the first time each year in Australia, according to a PBAC Drug Utilisation Sub-committee report from 2015.

The recommendation to subsidise combination therapy was first considered by the PBAC at its November 2018 meeting and it subsequently recommended dual therapy be subsidised.

Under the PBS-listing, new and grandfathered patients with PAH must undergo testing with Right Heart Catheterisation (RHC), echocardiogram and/or six-minute walk test, and written authority is required to prescribe the subsidised dual therapy.

Telephone or electronic authority is required for changes in dual therapy and continuing treatment on the PBS.

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