This is a multi-center, open-label two-part study evaluating the safety and tolerability of MT-3724 in combination with Lenalidomide in relapsed or refractory CD20 positive B-cell Lymphoma participants.~Part 1: (MT-3724 Dose Escalation) Define the maximum tolerated dose (MTD) of MT-3724 in combination with standard treatment of Lenalidomide~Part 2: (MTD Expansion Cohort) Confirm the safety and tolerability of the MTD of MT-3724 from Part 1 in the MTD Expansion Cohort, where MT-3724 will be given at the MTD in combination with Lenalidomide. In addition, the Pharmacokinetics (PK), Pharmacodynamics (PD), immunogenicity and tumor response at the MTD of MT-3724 in combination with Lenalidomide will be more thoroughly evaluated in Part 2.~It is anticipated that up to 64 participants will be enrolled. Treatment will continue until disease progression, withdrawal of consent or any other reason.
The purpose of this study is to evaluate the safety and tolerability of MT-3724 in combination with Lenalidomide in participants with relapsed or refractory B-Cell NHL.