Clinicians map role of MSD drug in pulmonary arterial hypertension post PBAC rejection

The Department of Health has released the outcomes from its pulmonary arterial hypertension (PAH) stakeholder meeting held in August. This follows the March PBAC meeting, which rejected MSD’s submission for Winrevair (sotatercept) as add-on therapy for patients with PAH, citing concerns over cost and target population alignment with treatment guidelines.

Clinicians strongly agreed that all newly diagnosed PAH patients should have access to at least dual therapy (ERA combined with PDE-5i), noting “the addition of a PDE-5i to an ERA often adds significant improvement with minimal adverse effects.” They also observed that some patients benefit from switching the PDE-5i to Adempas (riociguat) in combination with ERA.

In practice, some treatment units or patients themselves fund the cost of the second agent, typically the less expensive PDE-5i, where PBS eligibility rules block subsidised dual therapy. Clinicians argued this creates inequity in access to optimal PAH care, particularly as “it is counterintuitive to require patients with WHO FC II status to wait until their condition worsens before escalating to subsidised dual therapy.”

International guidelines have already shifted to support initiating dual drug therapy in newly diagnosed WHO FC II patients, and clinicians at the stakeholder meeting agreed there is “reasonable clinical evidence to support this practice.” They further noted that PBS continuation rules should not require a measure of response, stating “clinician judgement in assessing stability of disease and non-progression was adequate.”

On the PBAC decision not to recommend sotatercept, clinicians acknowledged the potential benefits of introducing a disease-modifying, anti-proliferative agent earlier in the treatment pathway. However, they agreed that, in the context of budget constraints, PBS subsidy should be prioritised for higher-risk patients (WHO FC III–IV) who have limited treatment options.

Clinicians emphasised that ERA plus PDE-5i dual therapy would remain the backbone of treatment for most patients, adding they were “doubtful that sotatercept would be used in patients with WHO functional class II status in place of an ERA plus PDE-5i.”

Instead, clinicians suggested sotatercept could be prioritised for:

• Patients on maximum tolerated triple therapy including Veletri (epoprostenol), as ‘add-on’ therapy where disease would otherwise progress to transplant or death.

• Patients receiving triple therapy with Uptravi (selexipag) due to intolerance or inability to use epoprostenol.

• Patients on dual therapy with inadequate response where prostanoids are unsuitable

While clinical trial results suggest sotatercept would see strong initial uptake if PBS-listed, clinicians warned that “serious side effects are likely to be a deterrent to uptake of sotatercept in practice as well as a cause of patients discontinuing this therapy.”

They further noted that selexipag should often be trialled before considering sotatercept, given the risk–benefit balance: “a patient should have a high or intermediate-high risk assessment to justify the risk of sotatercept side effects versus benefits.”

Clinicians also stressed the importance of flexibility in switching between therapies. Although switching data remain limited, “the flexibility to switch between selexipag, epoprostenol and sotatercept was needed to preserve patient choice of treatment options.”

Despite the PBAC’s rejection of subcutaneous injection sotatercept in patients with WHO FC II status, a resubmission in this population or an application presenting clinical evidence for use in patients with more severe PAH had not yet been submitted by MSD.

In reimagining healthcare across the entire patient journey, Health Industry Hub^TM is the only one-stop-hub uniting the diversity of the Pharma, MedTech, Diagnostics & Biotech sectors to inspire meaningful change.

The Health Industry Hub^TM content is copyright protected. Access is available under individual user licenses. Please click here to subscribe and visit T&Cs here.