Tolerance Bio has signed an agreement securing an exclusive licence from Tanabe Pharma for TLB-33, a clinical-stage anti-IL-33 monoclonal antibody, in a deal that includes potential development and sales milestone payments of up to around $560m.

The agreement grants Tolerance Bio exclusive commercialisation rights outside Japan, whilst Tanabe Pharma retains marketing rights within Japan.

The terms also include equity consideration and tiered royalties on net sales.

Through this contract, Tolerance Bio will seek to expand its portfolio focused on medicines that preserve and modulate thymic biology to address various immune diseases.

The company plans to initiate Phase II clinical development of TLB-33 to assess its use for thymic preservation and broader immune resilience and is also considering its application in additional immune indications.

The latest licence follows Tolerance Bio’s recent acquisition of NeoImmuneTech’s long-acting interleukin 7 (efineptakin alfa).

Tolerance Bio has also announced intentions to complete a financing round to support clinical trials for both assets.

TLB-33 has been tested in more than 150 participants across five separate clinical studies, yielding safety and pharmacological data.

According to Tolerance Bio, results provide proof-of-biological principle supporting ongoing clinical development, particularly in new indications such as thymic preservation.

Tolerance Bio CEO Francisco Leon said: “This agreement represents another important milestone for Tolerance Bio as we continue to build a clinical-stage pipeline around complementary approaches to thymic biology.”

“TLB-33 is a well-characterised clinical-stage antibody with substantial human safety and pharmacologic data, and its development builds on our team’s experience repositioning clinical-stage assets in high-value new indications.

“IL-33 signalling has been implicated in thymic involution in inflammatory settings, and we believe that blocking IL-33 offers an opportunity to preserve thymic function and improve immune resilience.”

TLB-33 is a human immunoglobulin G1 monoclonal antibody that targets and neutralises IL-33, an immune system mediator linked to thymic dysfunction and age-related immune decline.