Otsuka continues its bet on autoimmune therapies with $613M Cantargia antibody deal

Otsuka Pharmaceutical is paying $33 million upfront and offering up to $580 million in milestones for global rights to Sweden-based Cantargia’s IL1RAP-targeting autoimmune antibody program.

Why it matters: The deal expands Otsuka’s autoimmune R&D pipeline and marks a major investment in next-gen immunology treatments. Cantargia’s stock surged over 200% on the news.

Backstory: Cantargia’s lead candidate, CAN10, is in phase 1 trials for hidradenitis suppurativa (a skin condition also known as Verneuil's disease) and is also being evaluated for systemic sclerosis. Otsuka gains rights not only to CAN10 but also to a similar preclinical “backup antibody,” plus exclusive negotiation rights on future antibodies targeting IL1RAP, a key immune modulator in the IL-1 family.

Big picture: This move aligns with Otsuka’s broader autoimmune push, following recent deals and leveraging platforms from subsidiaries Visterra and Jnana Therapeutics. The IL1RAP platform could unlock treatments across multiple diseases.

• Otsuka’s recent autoimmune moves include a $600M+ deal for Harbour BioMed’s bispecific T-cell engager.

Yes, but: Otsuka's decision to prioritise autoimmune diseases may prove to be a judicious one, as other segments of its portfolio are facing challenges. Just ahead of Friday’s advisory committee vote, FDA staff raised concerns over conflicting efficacy data for brexpiprazole combined with sertraline in treating PTSD, leaving its approval uncertain. The drug was acquired as part of the $3.5 billion purchase of Avanir Pharmaceuticals in late 2014.