Golcadomide in Combination With Rituximab for the Treatment of Patients With Relapsed or Refractory Mantle Cell Lymphoma

Inclusion Criteria: * Documented informed consent of the participant and/or legally authorized representative * Agreement to allow the use of archival tissue from diagnostic tumor biopsies * If unavailable, exceptions may be granted with study principal investigator (PI) approval * Ability to adhere to the study protocol * Age: ≥ 18 years * Eastern Clinical Oncology Group (ECOG) ≤ 2 * Histologically confirmed diagnosis of MCL * Immunohistochemistry of the biopsy * Flow cytometry of the biopsy * Relapsed/ refractory disease * Relapsed/refractory (R/R) MCL after at least one line of therapy including resistant or intolerant to a cBTKi * Fully recovered from the acute toxic effects (except alopecia) to ≤ grade 1 to prior anti-cancer therapy * Ability to swallow pills * Without bone marrow involvement: Absolute neutrophil count (ANC) \> 1.5 × 10\^9/L (ANC \> 1,500/mm\^3) * With bone marrow involvement: ANC \> 1.0 × 10\^9/L (ANC \> 1000/mm\^3) * NOTE: Growth factor is not permitted within 14 days of ANC assessment unless cytopenia is secondary to disease involvement. For patients with significant marrow involvement, eligibility may be confirmed at the discretion of the treating investigator * Without bone marrow involvement: Platelets ≥ 75,000/mm\^3 * With bone marrow involvement: Platelets ≥ 50,000/mm\^3 * NOTE: Platelet transfusions are not permitted within 14 days of platelet assessment unless cytopenia is secondary to disease involvement * Total bilirubin ≤ …