Australian doctors should be able to prescribe combination therapy for patients with pulmonary arterial hypertension (PAH) in line with international guidelines.
Dr Edmund Lau, respiratory physician at the Royal Prince Alfred Hospital, told the limbic the current PBS restriction to monotherapy for patients with PAH was inadequate.
“There are three major classes of medications available for PAH and a high level of evidence for combination therapy,” Dr Lau said.
However doctors were currently relying on private scripts, compassionate access schemes and clinical trials to get their patients through, he said.
A retrospective analysis of 100 patients with PAH at the hospital found the majority of patients failed monotherapy within two years of treatment initiation.
Death or transplant was the most common reason for treatment failure.
“This reflects the aggressive nature of the underlying disease, despite targeted therapies,” the study said. “Our study highlights that monotherapy alone appears insufficient to achieve long-term stabilisation of PAH in the majority of patients.”
Dr Lau said the most common combination treatment used in Australia was bosentan and sildenafil because generic sildenafil can be obtained at relatively low cost outside the PBS.
However the combination lacks the evidence base available for other combinations such as ambrisentan and tadalafil.
Dr Lau said PAH was rare, affecting about 50-100 patients per million, but often severe.
“Only very mild patients respond to monotherapy,” he said.
“Given this a rare disease and there is good evidence for combination therapy, the overall health costs are not high. All of us would like to see more liberal subsidisation of PAH medications.”
The study found 1-year, 3-year and 5-year survivals for patients with PAH were 92%, 75% and 66% respectively.
Dr Lau added that intravenous prostacyclin for severe PAH was probably underutilised in Australia due to the burden of continuous infusion administration and limited access to specialised centres.