A Study of MT-2111 in Patients With Relapsed/Refractory DLBCL

Inclusion Criteria:

• Patients who were diagnosed pathologically with DLBCL, NOS, DLBCL transformed fromindolent B-cell lymphoma, or high-grade B-cell lymphoma with DLBCL morphology andwith MYC and BCL2 and/or BCL6 rearrangements, based on the 2017 WHO classification.

• Patients with relapsed or refractory disease despite 2 or more prior systemictherapies.

• Japanese patients aged ≥ 18 years at the time of informed consent. For Japanesesubjects, it should be confirmed that the parents who are related by blood to thesubject must be Japanese.

• Patients who have a lesion that can be assessed for staging and evaluated forresponse according to the Lugano criteria (2014). A lesion that has receivedradiotherapy as the most recent treatment will be considered as a measurable lesiononly when progression has been documented following completion of the radiotherapy.

• Patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 at screening.

Exclusion Criteria:

• Patients with a pathological diagnosis of Burkitt's lymphoma.

• Patients with bulky disease with the longest dimension of ≥ 10 cm.

• Patients with a history or complication of post-transplant lymphoproliferativedisorders.

• Patients with lymphoma with active central nervous system involvement at the time ofscreening, including leptomeningeal disease.

• Patients complicated with other active malignancies or patients with a history ofother malignancies within 3 years before informed consent. However, the followingare exceptional:

• Non-melanoma skin cancer

• Non-metastatic prostate cancer

• Cervical carcinoma in situ

• Ductal carcinoma in situ or lobular carcinoma in situ

• Patients with clinically significant third space fluid accumulation (e.g., ascitesrequiring drainage or pleural effusion requiring drainage or associated withshortness of breath).

• Patients who underwent autologous hematopoietic stem cell transplantation (AHSCT)within 30 days prior to the start of study drug administration (Cycle 1 Day 1).

• For the Phase I part, patients with prior allogeneic stem cell transplantation (Allo-HSCT) before the start of study drug administration (Cycle 1 Day 1). For thePhase II part, patients undergoing Allo-HSCT within 60 days prior to the start ofstudy drug administration (Cycle 1 Day 1).

• Patients who had a positive HIV antigen-antibody test or HIV antibody test.

• Patients positive for HBs antigen, HBc antibody, or HBs antibody. However, patientswho meet any of the following are eligible:

• The patient's HBs antibody positivity is clearly due to vaccination.

• Patients who are positive for HBs antibody and/or HBc antibody with HBV-DNA notdetected and agree to undergo HBV-DNA tests once a month from the start ofstudy drug administration to at least 12 months after the completion of studydrug administration.

• Patients positive for HCV antibody. However, patients with negative HCV-RNA areeligible.

• Patients who received anticancer therapy during the following periods prior to thestart of study drug administration (Cycle 1 Day 1).

• Cytotoxic chemotherapy: within 14 days.

• Antibody therapy: within 5 half-lives or 14 days, whichever is longer (including monoclonal antibody preparations, radioimmunoconjugates, orantibody-drug conjugates). Within 14 days for rituximab, anti-CD3/CD20bispecific antibody.

• Radiotherapy: within 14 days

• CAR-T therapy: within 100 days

• Other anticancer therapy: within 14 days

• Patients who received treatment with any other investigational product within 14days prior to the start of study drug administration (Cycle 1 Day 1). However, forthe Phase I part, patients who received any other investigational product within 14days or 5 half-lives, whichever is longer, before the start of study drugadministration (Cycle 1 Day 1).