Pulmonary arterial hypertension (PAH) is a rare, fatal cardiopulmonary disease with an annual mortality rate of approximately 10%. The PAH market has generated much interest and investment from drug developers over the past several years, despite the fact that PAH is a rare disease. Overall, the level of unmet need in the PAH market is high, and the greatest need is for novel drugs with curative or disease-stabilising properties. The currently available drugs work to slow the disease progression, but there is no marketed drug that addresses the underlying disease mechanism and is targeted at curing patients.

Over the past decade, the PAH disease space has consisted mainly of reformulations of existing PAH drugs and the repurposing of known drugs from other disease markets. Existing players in this space have focused on improving treatment delivery options, especially in the case of the prostacyclin analogue class of drugs. While currently marketed PAH therapies focus on dilating the partially occluded vessels and are weak anti-proliferative agents, they are not effective in reversing vascular remodelling, thus preventing deterioration and the need for a lung transplant.

GlobalData believes that it will be easier for new drug entrants to capture market share if they target a novel fourth pathway. For example, most key opinion leaders (KOLs) interviewed by GlobalData expressed strongly positive opinions about Acceleron Pharma’s sotatercept, a first-in-class fusion protein in development for PAH treatment.  Sotatercept prevents blood vessel remodelling by restoring vascular homeostasis between cell proliferation and apoptosis by signalling via the bone morphogenetic protein receptor type 2, positioning it as a potential major advancement in the treatment of PAH. Additionally, sotatercept has the potential to serve as an add-on therapy to already established combination therapies.

GlobalData has identified five PAH drugs in late-stage clinical development (Phase IIb or later) and 27 more in early stages (Phase I and Phase II). These include a prostacyclin receptor agonist (PRA), PDE5 inhibitor, nitric oxide synthase endothelial activator, angiotensin-converting enzyme 2, and BMP10 inhibitor. The figure below outlines the key Phase III/Phase IIb trials for the promising late-stage pipeline agents that GlobalData expects to be licensed for the treatment of PAH in the seven major markets (7MM) (US, France, Germany, Italy, Spain, UK, and Japan) during the forecast period. While the potential launch of these late-stage pipeline agents will increase the number of pharmacological treatment options that can be offered to PAH patient populations with high unmet need, such as functional classes 3 and 4, some patients may not benefit from them due to challenges associated with gaining favourable reimbursement due to their anticipated high annual cost of therapy.

Figure 1: Key Phase II/III Trials for the Promising Pipeline Agents that GlobalData Expects to Be Licensed for PAH in the 7MM During the Forecast Period.

Credit: GlobalData.

The PRAs currently in late-stage development include United Therapeutics’ Trevyent (treprostinil) and ralinepag. These pipeline agents enable easier, more convenient, and less error-prone drug administration, demonstrating that they have the potential for clinical superiority over existing PRA PAH treatments. Apeiron Biologics’ APN-01 is administered intravenously. Improved cardiac output was observed without worsening pulmonary hypertension in clinical trial results for APN-01, and KOLs have indicated that it could serve as an add-on therapy to already established combination therapies. Mezzion Pharma’s udenafil will be the third PDE5 inhibitor to be launched, if approved, and will face fierce competition from Eli Lilly’s Adcirca (tadalafil) and Pfizer’s Revatio (sildenafil). Phasebio Pharmaceuticals’ Vasomera (PD1046) and Northern Therapeutics’ Aurora-GT (nitric oxide synthase endothelial activator) have the potential to capture a target patient population with severe PAH if approved, as both drugs have a novel mechanism of action in the PAH space. With pipeline approvals of varying mechanisms and an influx of newly diagnosed patients in the 7MM, the PAH market is expected to grow at a 5% CAGR through 2029.