Royalty Pharma pays up to $425m for cliramitug royalty stake

Royalty Pharma has acquired a portion of Neurimmune's royalty interest in AstraZeneca's cliramitug, committing up to $425 million in a deal that underscores growing investor appetite for cardiovascular amyloidosis assets. The NASDAQ-listed royalty aggregator will pay $125 million upfront, a further $125 million in the first quarter of 2027, and up to $175 million contingent on clinical and regulatory milestones, in exchange for a 3% to 4% royalty on worldwide net sales.

Cliramitug is a monoclonal antibody targeting transthyretin fibrils already deposited in the heart, differentiating it mechanistically from currently approved ATTR-CM therapies such as tafamidis, which acts upstream to stabilise TTR protein and slow further accumulation. The candidate is being evaluated in the Phase 3 DepleTTR-CM trial, with results guided by AstraZeneca for 2028. AstraZeneca has previously set a peak sales target of between $3 billion and $5 billion for the asset.

The deal mechanics

Under the terms disclosed, Neurimmune retains the majority of its royalty and milestone interests in cliramitug, with Royalty Pharma acquiring only a portion of those entitlements. Roger Nitsch, president and chief executive of Neurimmune, said the proceeds would support the Swiss biotech's internal research pipeline while maintaining meaningful economic participation in cliramitug's commercial outcome.

Pablo Legorreta, chief executive and chairman of Royalty Pharma, described cliramitug as the company's second recent investment in the ATTR-CM indication, suggesting the firm is building a deliberate concentration in the space. Royalty Pharma's existing portfolio spans more than 35 commercial products and 20 development-stage candidates, giving the company the balance-sheet depth to absorb milestone-contingent structures of this size.

Market context and competitive read-across

The ATTR-CM market expanded by more than 40% in 2025 to exceed $7 billion in annual sales, driven by broader diagnostic awareness and the commercial uptake of stabiliser therapies. That growth trajectory makes the indication attractive to royalty investors precisely because the market infrastructure is already established: cardiology referral pathways are in place and reimbursement frameworks exist in major markets.

Cliramitug's fibril-depleting mechanism is shared in concept with other investigational amyloid-clearance approaches, including antibody programmes from a number of earlier-stage biotechs pursuing cardiac and systemic amyloidosis. If the DepleTTR-CM Phase 3 readout in 2028 demonstrates meaningful regression of existing amyloid burden alongside a manageable safety profile, it would offer AstraZeneca a genuinely additive label claim relative to approved agents. The key regulatory question, particularly for the FDA and EMA, will be whether amyloid clearance translates to durable functional and survival benefit, a bar that has proved demanding in adjacent amyloid disease areas.

For Royalty Pharma, the structured payment schedule limits near-term cash outflow while locking in a royalty rate before a potentially transformative dataset lands. The deal also illustrates the continuing utility of the royalty-finance model for innovators such as Neurimmune that wish to monetise a portion of their upside without diluting equity or surrendering operational control. Whether the $3-5 billion peak sales projection proves achievable will depend heavily on how the 2028 data read out and how quickly payers are willing to reimburse a premium-priced depleter on top of, or instead of, existing stabiliser therapy.