Ionis Pharmaceuticals, Inc. announced that it closed its expanded strategic collaboration with Biogen to discover and develop novel antisense drugs for a broad range of neurological diseases following receipt of clearance under the Hart-Scott-Rodino (HSR) Antitrust Improvements Act of 1976. Biogen paid Ionis $1 billion in cash, which included $625 million for the purchase of 11,501,153 shares of Ionis common stock at a price of $54.34 per share and a $375 million upfront payment.

On April 20, 2018, Ionis and Biogen announced they would expand their strategic collaboration to develop novel antisense drugs for a broad range of neurological diseases through a new ten-year collaboration. This collaboration capitalizes on Ionis' leadership in RNA-targeted therapies as well as Ionis and Biogen's joint expertise in neuroscience research and drug development. It builds upon a productive collaboration that produced Spinraza (nusinersen), the first and only approved treatment for patients with spinal muscular atrophy.

The companies plan to advance programs for a broad range of neurological diseases for which few treatment options exist today. Disease areas include dementia, neuromuscular diseases, movement disorders, ophthalmology, diseases of the inner ear, and neuropsychiatry.

Ionis will be responsible for the identification of antisense drug candidates based on selected targets, while Biogen will have the option to license therapies arising out of this collaboration and will be responsible for and pay for non-clinical studies, clinical development, manufacturing, and commercialization. In addition, Biogen may pay milestone payments, license fees and royalties on net sales.

Ionis is the leading company in RNA-targeted drug discovery and development focused on developing drugs for patients who have the highest unmet medical needs, such as those patients with severe and rare diseases.