Bayer bags FDA green light for stroke drug Sunharbo

Bayer's oral Factor XIa inhibitor asundexian has been cleared in the US, a couple of weeks after its world-first approval in China, in another major step forward for the company's recovery plan.

Asundexian has been approved by the FDA under the Sunharbo brand name for use in combination with antiplatelet therapy to reduce the risk of stroke in adults who have had a recent mild-to-moderate non-cardioembolic ischemic stroke or a high-risk transient ischemic attack (TIA).

It is the first drug in the oral factor XIa (FXIa) inhibitor class to be cleared for marketing in the US, ahead of its closest rival – milvexian – which is being developed by Bristol Myers Squibb and Johnson & Johnson but has not yet been submitted for approval in any market.

Another potential rival is Novartis' anti-FXI/FXIa antibody abelacimab, acquired as part of its $3.1 billion takeover of Anthos last year, but that is also in late-stage clinical development.

According to Bayer, Sunharbo could be an option for the approximately 795,000 ​people in the US each year who experience a stroke. Despite current therapies, around 20% of them will go on to have another stroke within the next five years, often with more devastating neurological consequences.

In the large-scale OCEANIC-STROKE study, adding asundexian to standard antiplatelet therapy in this setting resulted in a 26% fall in the risk of a secondary stroke compared to placebo, with no increase in the risk of major bleeding complications – a perennial concern for anti-clotting therapies.

The drug was also able to reduce the risk of a composite endpoint of cardiovascular death, myocardial infarction (MI), or stroke, as well as death from any cause, MI, or stroke in the study, which was published in the New England Journal of Medicine earlier this year.

"This FDA approval represents a bold step forward in post-stroke care," said Christian Rommel, Bayer's R&D chief, noting that stroke "requires substantial healthcare resource utilisation and presents a significant economic and personal burden."

Analysts have suggested that Sunharbo could eventually reach around €3 billion in annual sales. Bayer's publicly revealed internal sales forecasts are more modest at around €1 billion, having been trimmed after the drug failed a phase 3 trial in atrial fibrillation (AF), a much larger indication than stroke prevention.

Either way, it adds a third growth product for Bayer alongside prostate cancer therapy Nubeqa (darolutamide) and Kerendia (finerenone) for chronic kidney disease and heart failure, which are largely responsible for the turnaround in the fortunes of Bayer's pharma division this year.

Bayer has said that a 30-day supply of Sunharbo 50 mg tablets, the standard once-daily dose, will have a list price of $748.50.