New radiation 'Smart Bomb' targets Hard-to-Treat myeloma

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Documented informed consent of the participant and/or legally authorized representative * Assent, when appropriate, will be obtained per institutional guidelines * Age \>= 18 years * Karnofsky performance status (KPS) \> 60% * Multiple myeloma according to International Myeloma Working Group (IMWG) criteria with measurable disease defined as one of the following: * Serum monoclonal protein \>= 1.0 g/dL (or 0.5 g/dL in patients with immunoglobulin A \[IgA\] multiple myeloma \[MM\]) * 24 hour urine monoclonal protein \>= 200 mg/24 hour * Serum free light chain (FLC) of \> 10 mg/dL and an abnormal kappa:lambda ratio * Minimum of two prior lines of therapy * Previously received treatment with all of the following: a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 monoclonal antibody. Refractory (defined per IMWG Consensus Criteria) to daratumumab * CD38 expression on multiple myeloma (MM) cells from bone marrow aspirate or biopsy as demonstrated by flow cytometry or immunohistochemistry * Refractory (defined per IMWG Consensus Criteria) or intolerant to most recent therapy * Fully recovered from the acute toxic effects (except alopecia) to =\< grade 1 to prior anti-cancer therapy * Prior antitumor therapy must have been completed prior to enrollment as follows: * \>= 21 days for investigational agents, cytotoxic chemotherapy * \>= 21 days for radiation therapy. Note: Patients must have measurable disease that has been untreated/unaffected by local radiation therapy * \>= 3 months for prior anti-CD38-targeted therapy, adoptive cell therapy * \>=14 days for proteasome inhibitor therapy * \>= 7 days for immunomodulatory agents * Absolute neutrophil count (ANC) \>= 1,000/mm\^3 (within 14 days prior to day 1 of protocol therapy) * NOTE: Growth factor is not permitted within 7 days of ANC assessment unless cytopenia is secondary to disease involvement * Platelets \>= 75,000/mm\^3 (\>= 50,000/mm\^3 if \>= 50% marrow involvement) (within 14 days prior to day 1 of protocol therapy) * NOTE: Platelet transfusions are not permitted within 14 days of platelet assessment unless cytopenia is secondary to disease involvement * Total bilirubin =\< 1.5 x upper limit of normal (ULN) (unless has Gilbert's disease) (within 14 days prior to day 1 of protocol therapy) * Aspartate aminotransferase (AST) =\< 3 x ULN (within 14 days prior to day 1 of protocol therapy) * Alanine aminotransferase (ALT) =\< 3 x ULN (within 14 days prior to day 1 of protocol therapy) * Creatinine =\< 1.5 mg/dl AND/OR creatinine clearance of \>= 40 mL/min per 24 hour urine test or the Cockcroft-Gault formula (within 14 days prior to day 1 of protocol therapy) * Women of childbearing potential (WOCBP): negative urine or serum pregnancy test * If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required (within 14 days prior to day 1 of protocol therapy) * Woman of childbearing potential must be practicing a highly effective method of birth control consistent with local regulations regarding the use of birth control methods for subjects participating in clinical studies: e.g., established use of oral, injected or implanted hormonal methods of contraception; placement of an intrauterine device or intrauterine system; barrier methods; condom with spermicidal foam/gel/film/cream/suppository or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository; male partner sterilization; true abstinence (when this is in line with the preferred and usual lifestyle of the subject) during and after the study (6 months after the last dose of 225Ac-DOTA-Daratumumab for women). A man who is sexually active with a woman of childbearing potential and has not had a vasectomy must agree to use a barrier method of birth control, e.g., either condom with spermicidal foam/gel/film/cream/suppository or partner with occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository, and all men must also not donate sperm during the study and for 6 months after receiving the last dose of study drug * Childbearing potential defined as not being surgically sterilized (men and women) or have not been free from menses for \> 1 year (women only) Exclusion Criteria: * Daratumumab or other anti CD38 antibody treatment \< 3 months prior to study enrollment * Prior radiopharmaceutical therapy * Detectable antibodies directed against daratumumab * Subject has received previous radiation to \> 25% of their bone marrow * Female patients who are lactating or have a positive pregnancy test during the screening period * Major surgery within 14 days prior to start of study treatment * Subject is receiving concurrent chemotherapy, radiation, or biologic for cancer treatment. Subject is receiving bone marrow stimulatory factors (e.g., granulocyte-macrophage colony-stimulating factor \[GM-CSF\]). Note: Hormonal therapy for someone with a history of cancer treated with curative intent is permitted if subject has been on hormonal therapy \> 1 year * Vaccination with live attenuated vaccines within 4 weeks of study agent administration * A diagnosis of primary amyloidosis, plasma cell leukemia, Waldenstrom macroglobulinemia, or POEMS * Severe persistent asthma (forced expiratory volume in 1 second \[FEV1\] \< 60% and/or daily symptoms) or severe chronic obstructive pulmonary disease (COPD) defined clinically or by historical pulmonary function tests with an FEV1 \< 50% predicted * Subject has known allergies, hypersensitivity, or intolerance to monoclonal antibodies or human proteins, or their excipients (refer to respective package inserts or investigator's brochure). Patients with a history of infusion reactions to daratumumab with prior treatment that resolved with supportive measures and in whom daratumumab therapy was not previously discontinued because of infusion reactions are permitted * Subject has uncontrolled human immunodeficiency virus (HIV-1), chronic or active hepatitis B, or active hepatitis A or C * Patients with HIV are eligible unless their CD4+ T-cell counts are \< 350 cells/mcL or they have a history of acquired immunodeficiency syndrome (AIDS)-defining opportunistic infection within the 12 months prior to registration. Concurrent treatment with effective antiretroviral therapy (ART) according to Department of Health and Human Services (DHHS) treatment guidelines is recommended * Subject has any one of the following: * Clinically significant abnormal electrocardiogram (ECG) finding at screening * Congestive heart failure (New York Heart Association class III or IV) * Myocardial infarction within 12 months prior to starting study treatment * Unstable or poorly controlled angina pectoris, including Prinzmetal variant angina pectoris * Subject has presence of other active malignancy \[see exceptions below\] (However, research participants with history of prior malignancy treated with curative intent and in complete remission are eligible). The following malignancies are exceptions to the active malignancy statement: * Basal cell carcinoma of the skin * Squamous cell carcinoma of the skin * Non-muscle invasive bladder cancer * Carcinoma in situ of the cervix * Carcinoma in situ of the breast * Incidental histologic finding of prostate cancer (T1a or T1b using the TNM clinical staging system) or prostate cancer that is curative * Any other condition that would, in the investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures * Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)