MEN1703 (SEL24) to Treat Relapsed or Refractory Aggressive B-cell Non-Hodgkin Lymphoma (JASPIS-01)

The goal of the study is to assess the safety and anti-lymphoma activity of MEN1703 (Dapolsertib hydrochloride) when given as a single-agent or combined with glofitamab to patients with relapsed/refractory (R/R) aggressive B-cell non-Hodgkin lymphoma. The study will be open to groups at the same time: * Group 1 - patients who have not had anti-CD3xCD20 bispecific antibody therapy but who have had at least 2 prior lines of systemic treatment for aggressive B-cell non-Hodgkin lymphoma * Group 2 - patients who have exhausted all standard treatment options including at least 2 prior lines of systemic treatment for aggressive B-cell non-Hodgkin lymphoma Group 1 patients will be treated for a maximum of 12 cycles. One cycle is 21 days. Group 2 with be treated until the disease progresses, therefore treatment duration is dependent on the number of treatment cycles a participant receives prior to progression.

The study consists of 3 parts, to investigate MEN1703 (Dapolsertib hydrochloride) in combination with glofitamab in patients who are naïve to treatment with an anti-CD3xCD20 bispecific antibody (group 1) or MEN1703 alone in patients who have exhausted all standard treatment options (group 2). Part 1 (safety run-in) and Part 2 (enrichment): patients who are naïve to treatment with an anti-CD3xCD20 bispecific antibody (group 1) will receive either 150 mg or 125 mg of MEN1703 along with glofitamab. Patients who have exhausted all standard treatment options (group 2) will receive 125 mg of MEN1703 as a single-agent. Part 3 (optional randomized comparison): Patients who are naïve to treatment with an anti-CD3xCD20 bispecific antibody therapy will be randomized to receive either MEN1703 (Dapolsertib hydrochloride) at a dose selected from part 2 in combination with glofitamab or glofitamab alone.