Ionis Pharmaceuticals Inks Major Licensing Deal with Ono for Polycythemia Vera Drug

Ionis Pharmaceuticals has entered into a significant licensing agreement with Japanese firm Ono Pharmaceutical, granting exclusive global rights to develop and commercialize sapablursen, an investigational antisense oligonucleotide therapy for polycythemia vera. The deal, announced on Tuesday, is valued at nearly $1 billion in potential payments, marking a substantial development in the treatment landscape for this rare blood disease.

Deal Structure and Financial Terms

Under the terms of the agreement, Ionis will receive an upfront payment of $280 million from Ono Pharmaceutical. The deal also includes the potential for up to $660 million in additional milestone payments tied to development, regulatory, and commercial achievements. Furthermore, Ionis stands to earn mid-teen-percentage royalties from future sales of sapablursen, should it gain regulatory approval.

The transaction is still subject to antitrust clearance and has not yet closed, as reported by both companies.

Sapablursen: Mechanism and Clinical Progress

Sapablursen represents a novel approach to treating polycythemia vera, a condition characterized by the overproduction of red blood cells. The drug candidate is designed to lower the expression of the TMPRSS6 gene, which in turn boosts the production of hepcidin, a protein crucial for iron homeostasis regulation. By improving hepcidin expression, sapablursen aims to alleviate the severity of polycythemia vera symptoms.

The therapy is currently undergoing evaluation in the Phase II IMPRSSION study, which completed enrollment in late 2024. Topline data from this trial is anticipated later this year. As part of the licensing agreement, Ionis will complete the IMPRSSION trial before handing over further development responsibilities to Ono Pharmaceutical.

Strategic Implications and Industry Context

This licensing deal comes on the heels of another significant agreement for Ionis, involving its hypertension candidate tonlamarsen. The rapid succession of these partnerships underscores Ionis' strategy to leverage its antisense oligonucleotide platform across multiple therapeutic areas.

For Ono Pharmaceutical, the acquisition of sapablursen rights represents a strategic expansion into the rare disease space, particularly in hematology. The Japanese firm will take charge of late-stage development, regulatory filings, and commercialization activities for sapablursen globally, signaling its commitment to bringing this potential treatment to patients with polycythemia vera.

As the pharmaceutical industry continues to focus on rare diseases and innovative treatment modalities, deals such as this highlight the ongoing interest in antisense oligonucleotide therapies and their potential to address unmet medical needs.