Overall Response Rate

A: Daratumumab & Dexamethasone

All participants will receive 1800 mg in 15 ml Daratumumab by subcutaneous injection weekly and be given 20 mg of Dexamethasone orally once a week for 2 months. Patients who receive a partial response or better will continue on this arm. Daratumumab Injection: Patient will receive daratumumab (1800 mg in 15 ml) administered by manual subcutaneous injections weekly for the first 8 weeks, every other week for the next 16 weeks and every 4 weeks after. Dexamethasone Oral: The dexamethasone starting dose will be 20 mg PO once a week. Commercial dexamethasone will be used. Dexamethasone is often supplied in 4 mg tablets. Accordingly, patients will take 5 (4 mg tablets) one day of the week prior to the administration of daratumumab if this corresponds to a daratumumab dosing days. In non daratumumab dosing days, dexamethasone will be taken by the patient at home, usually in the morning with breakfast.

B: Daratumumab, Dexamethasone and Lenalidomide

Participants who have less than a partial response to Arm A may have Lenalidomide added to their treatment. Lenalidomide will be given orally on days 1-21 of each 28 day treatment cycle. Daratumumab Injection: Patient will receive daratumumab (1800 mg in 15 ml) administered by manual subcutaneous injections weekly for the first 8 weeks, every other week for the next 16 weeks and every 4 weeks after. Dexamethasone Oral: The dexamethasone starting dose will be 20 mg PO once a week. Patients will take 5 (4 mg tablets) one day of the week prior to the administration of daratumumab if this corresponds to daratumumab dosing days. Non daratumumab dosing days, dexamethasone will be taken by the patient at home. Lenalidomide Pill: Lenalidomide will be given orally on days 1-21 of a 28 days cycle. The starting dose of lenalidomide will be based on the patient creatinine clearance per the package insert. Specifically patients with a creatinine clearance ≥ 50 ml/min will receive 25 mg of lenalidomide PO Days 1-21. Patients with a creatinine clearance ≥ 30 but less than 50 ml/min will receive 10 mg of lenalidomide. Patients with a creatinine clearance \< 30 ml/min are not eligible. Patients who experience a deterioration in renal function during screening or treatment may continue on lenalidomide therapy as long as the risk / benefit profile is deemed acceptable after discussion with the study principal investigator / sponsor.

C: Daratumumab, Dexamethasone and Bortezomib

Participants who have less than a partial response to Arm A may have Bortezomib added to their treatment. Bortezomib will be given weekly in subcutaneous injections at a starting dose of 1/3 mg/m\^2 Days 1,8 and 15 of each 28 day treatment cycle. Daratumumab Injection: Patient will receive daratumumab (1800 mg in 15 ml) administered by manual subcutaneous injections weekly for the first 8 weeks, every other week for the next 16 weeks and every 4 weeks after. Dexamethasone Oral: The dexamethasone starting dose will be 20 mg PO once a week. Commercial dexamethasone will be used. Dexamethasone is often supplied in 4 mg tablets. Accordingly, patients will take 5 (4 mg tablets) one day of the week prior to the administration of daratumumab if this corresponds to a daratumumab dosing days. In non daratumumab dosing days, dexamethasone will be taken by the patient at home, usually in the morning with breakfast. Bortezomib Injection: Bortezomib will be given weekly subcutaneously in an effort to decrease the toxicity of the therapy. Specifically patients will receive a starting dose of bortezomib of 1.3 mg/m\^2 Days 1,8,15 of a 28 day cycle. Bortezomib will be administered in the cancer center per standard of care procedures.

Analysis denominator · Participants