Tolerance Bio, Inc. has entered into an exclusive license agreement with Tanabe Pharma Corporation for MT-2990, now known as TLB-33, a clinical-stage anti-interleukin-33 (IL-33) monoclonal antibody. Under the agreement, Tolerance Bio has secured worldwide development and manufacturing rights for TLB-33 across all indications, along with exclusive commercialisation rights outside Japan. Tanabe Pharma will retain commercialisation rights in Japan.

Tolerance Bio plans to advance TLB-33 into Phase 2 clinical development to evaluate its potential to preserve thymic function and support immune resilience. The company is also considering additional immune-related indications for the programme.

The agreement expands Tolerance Bio's clinical-stage pipeline focused on thymic biology and follows its recently announced licensing of efineptakin alfa, a long-acting interleukin-7 (IL-7) therapy from NeoImmuneTech. The company said it expects to announce the completion of a financing round to support the development of TLB-33 and efineptakin alfa through planned clinical trials.

TLB-33 is a human immunoglobulin G1 (IgG1) monoclonal antibody designed to bind to and neutralise IL-33. IL-33 is an alarmin released in response to cellular stress or tissue injury and is involved in the activation of innate and adaptive immune responses. According to Tolerance Bio, dysregulated IL-33 signalling has been associated with inflammatory pathways that may contribute to thymic dysfunction, age-related decline in immune function and acute thymic involution in certain immune conditions.

The thymus plays a central role in T-cell maturation and immune function. It progressively decreases in activity with age and can undergo acute involution in response to inflammatory conditions. Tolerance Bio is developing TLB-33 to investigate whether modulation of IL-33 signalling can help preserve thymic output and support immune resilience.

TLB-33 has been evaluated in more than 150 subjects across five clinical studies. The company said the available safety, tolerability, pharmacologic and clinical data provide a basis for further clinical development in new indications aligned with its thymic-biology strategy.

With the addition of TLB-33, Tolerance Bio's pipeline now includes multiple therapeutic modalities targeting thymic function, including biologics, thymus-targeted mRNA and cell therapies. The company is developing these programmes with the aim of preserving, regenerating and modulating thymic function.

Under the licensing agreement, Tanabe Pharma is eligible to receive potential development and sales milestone payments of up to approximately USD 560 million, in addition to equity consideration and tiered royalties on net sales.