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Otsuka and Ionis enter into licensing agreement for hereditary angioedema

Otsuka and Ionis Pharmaceuticals, a leader in RNA-targeted therapy based in California, have entered into a licence agreement for Otsuka to acquire exclusive marketing rights to the Ionis hereditary angioedema (HAE) drug candidate, donidalorsen (generic name), in Europe.

Donidalorsen is an investigational ligand-conjugated antisense (LICA) medicine designed to target the prekallikrein, or PKK, pathway1. PKK plays an important role in activating inflammatory mediators associated with acute attacks of hereditary angioedema2. The Phase 2, open-label, extension study demonstrated donidalorsen reduced HAE attack rate by a mean of 96%, from 2.70 attacks per month to 0.06 attacks per month over 2 years with treatment being well tolerated3,4. Ionis is currently conducting two Phase 3 multicentre studies; a double-blind, placebo-controlled study in North America and Europe and an open-label, global study. Donidalorsen has received Orphan Drug Designation in the US in 2023.

Under the terms of the agreement, Otsuka will pay Ionis an upfront payment of $65 million, plus payments based on achievement of regulatory and sales milestones. Otsuka will apply for regulatory approval and exclusively commercialise the product in Europe.

Makoto Inoue, president and representative director of Otsuka commented: “Otsuka is committed to the development of drugs for rare diseases such as autosomal dominant polycystic kidney disease (ADPKD). Through this collaboration with Ionis, if regulatory approval is received, we look forward to bringing donidalorsen to patients in Europe to address the unmet medical needs of patients with HAE.”

Brett P. Monia, Ph.D., Ionis chief executive officer said: “We are excited to collaborate with Otsuka given their proven results in bringing rare disease medicines to patients in Europe. This agreement is aligned with our strategy to initially focus our commercialisation efforts on the US market. We are encouraged by the product profile of donidalorsen to date and look forward to reporting pivotal topline Phase 3 results in HAE in the first half of next year.”


1 Donidalorsen. Ionis Pharmaceuticals, Inc. Available online: Last accessed: December 2023.

2 Schmaier AH. Plasma Prekallikrein: Its Role in Hereditary Angioedema and Health and Disease. Front Med (Lausanne). 2018 Jan 25;5:3.

3 Cohn DM, Newman KB, Bordone L, et al. Two-Year Analysis of the Donidalorsen Phase 2 Open-Label Extension Study in Patients With Hereditary Angioedema. E-poster presented at the American College of Allergy, Asthma & Immunology 2023 Annual Scientific Meeting; November 9–13; Anaheim, CA. Available online: Last accessed: December 2023.

4 An Extension Study of Donidalorsen (IONIS-PKK-LRx) in Participants With Hereditary Angioedema. NCT04307381. Available online: Last accessed: December 2023.


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