New York-based Royalty Pharma plc (Nasdaq: RPRX) has agreed to buy a slice of Neurimmune's royalty interest in cliramitug, AstraZeneca's Phase III antibody for transthyretin amyloid cardiomyopathy, in a deal worth up to $425 million, according to the companies' announcement. The transaction, disclosed alongside a parallel statement from Neurimmune, gives the world's largest biopharmaceutical royalty buyer economic exposure to a molecule still two years from a pivotal readout, in one of the fastest-growing indications in cardiology.
Cliramitug (ALXN-2220; NI006) is described by Neurimmune, the private Swiss antibody developer that originated the molecule, as a TTR-fibril-depleting monoclonal antibody designed to clear amyloid deposits already accumulated in the heart, rather than to slow further buildup. That distinguishes it mechanistically from the two approved drug classes in ATTR-CM: TTR stabilizers such as tafamidis, which prevent the transthyretin tetramer from dissociating into amyloidogenic monomers, and RNA-targeting silencers such as patisiran and vutrisiran, which reduce hepatic TTR production. Neither approved approach removes amyloid already deposited in cardiac tissue.
Under the agreement, Royalty Pharma will pay Neurimmune USD 125 million upfront in exchange for a 3% to 4% royalty on worldwide net sales of cliramitug. A further USD 125 million is due in the first quarter of 2027 as a scheduled, non-milestone-gated payment, with the remaining USD 175 million contingent on unspecified clinical and regulatory milestones. Neurimmune retains the majority of its royalty and milestone interests in cliramitug, framing this as a partial monetization intended to fund the company's broader pipeline rather than a full exit from the asset. Goodwin Procter and Maiwald advised Royalty Pharma on the transaction.
Cliramitug remains in the Phase III DepleTTR-CM trial, with results expected in 2028 based on AstraZeneca's guidance. AstraZeneca has set a peak sales target of USD 3 billion to USD 5 billion for the drug, presented at its May 2024 investor day, in a market that Royalty Pharma says grew more than 40% in 2025 to exceed USD 7 billion in global sales.