UCB buys Candid Therapeutics for $2.2B, boosting T-cell engagers in autoimmune disease

The Belgian pharmaceutical giant is doubling down on a bold therapeutic hypothesis. UCB has agreed to acquire San Diego-based Candid Therapeutics for up to $2.2 billion, a deal that underscores the industry’s growing conviction that T-cell engagers (TCEs) originally designed for cancer can be repurposed to fundamentally alter the treatment of autoimmune diseases.

Candid is a young company with no approved products. Its lead candidate, cizutamig, has only been tested in roughly 100 patients across early-stage trials. Yet the price tag is substantial: $2 billion in upfront cash, with an additional $200 million tied to development and regulatory milestones. The transaction, announced on May 3, is expected to close by early in the third quarter, pending antitrust clearance. UCB has maintained its 2026 financial guidance, signaling confidence in absorbing the cost.

This marks UCB’s second major bet on T-cell engagers in recent months. Earlier, it licensed ATG-201, a CD19/CD3 bispecific from China’s Antengene, in a deal worth up to $1.1 billion. The Candid acquisition adds a complementary mechanism targeting BCMA, a different B-cell antigen.

Cizutamig is a bispecific antibody that bridges T-cells to plasma cells. It was originally developed for multiple myeloma, where destroying rogue plasma cells is the goal. The 2026 thesis is that the same mechanism can be deployed to eliminate the autoreactive B-cells and plasma cells driving diseases like lupus, myasthenia gravis, and other autoimmune conditions. According to UCB, cizutamig has been evaluated in over 100 patients across both myeloma and autoimmune indications, and is currently in Phase 1 studies for more than ten autoimmune diseases.

UCB describes the asset as a potential best-in-class BCMA T-cell engager for autoimmune disease. The enthusiasm stems from early clinical signals that have been genuinely striking. Patients with severe disease have achieved durable remissions after a single course of therapy, even in conditions where decades of conventional treatment had only provided partial control. While late-stage data and longer follow-up are still needed, the direction has been consistent enough to justify significant investment.

Candid was founded in 2024 with $370 million in launch financing from Two River Group and Vida Ventures. Its chairman and CEO, Dr. Ken Song, previously led RayzeBio through its $4.1 billion acquisition by Bristol Myers Squibb in late 2023. His track record of building and selling clinical-stage oncology and immunology biotechs is a key part of what UCB is paying for. The jump from a $370 million valuation in mid-2024 to a $2 billion upfront payment less than two years later reflects that confidence.

The deal also represents a sharp reversal. In March, Candid had announced a reverse merger with Rallybio, a smaller public rare-disease company, to go public via a back-door listing. That plan has now been superseded by UCB’s offer.

UCB’s move fits a broader industry pattern. Over the past nine months, nearly every major pharma company with an immunology presence has acquired, licensed, or partnered around T-cell engagers for autoimmune disease. Gilead bought Ouro Medicines for $2.18 billion, picking up a BCMAxCD3 engager. Sanofi licensed a trispecific from Kali Therapeutics for up to $1.2 billion. GSK paid $300 million for a lupus candidate from Chimagen. Prolium Bioscience launched with $50 million for a CD20xCD3 engager. The list grows almost weekly.

Two factors explain the rush. First, the science appears to be generalizable: what works in oncology to kill malignant B-cells also works in autoimmune disease to remove autoreactive ones, and the early human data are far better than conventional pharmacology predicted. Second, immunology is the largest pharmaceutical market after oncology. Drugs like AbbVie’s Humira and Sanofi’s Dupixent demonstrate the revenue potential. If TCEs work in this setting, the prize is enormous. If they do not, several deals will look expensive in retrospect.

Notably, this deal is not driven by AI. Despite the surge of attention to AI-discovered medicines from companies like Isomorphic Labs, ByteDance’s Anew Labs, and Anthropic, cizutamig is a conventionally designed biologic. It was discovered through licensing and standard antibody engineering. The molecules driving today’s autoimmune deal flow are products of a previous decade’s chemistry. AI’s promised acceleration in drug discovery has so far produced more announcements than approvals.

For UCB, the strategic logic is clear. The company is mid-sized with a strong immunology franchise and a recent track record of targeted M&A. Pairing the Antengene CD19xCD3 candidate with Candid’s BCMAxCD3 asset gives it two complementary B-cell-depleting mechanisms in a market that increasingly rewards platform breadth.

What UCB must now prove is execution. Phase 1 data in autoimmune disease are encouraging but thin. Competitive density is high, with at least half a dozen large pharma companies pursuing similar mechanisms across overlapping indications. Pricing pressure will hit any successful TCE near approval, and manufacturing bispecific antibodies at scale is non-trivial. None of these challenges is fatal, but all are real.

By the time the deal closes this summer, the broader market may have adjusted its enthusiasm for the modality. UCB has chosen to act before that adjustment. Whether that proves timely or expensive will be visible in the Phase 2 readouts due over the next 18 months. For now, a two-year-old company founded by an experienced operator has been priced at $2.2 billion in cash by a pharma company convinced the bet is correct.