Daratumumab for Relapsed/Refractory Primary Effusion Lymphoma, Plasmablastic Lymphoma, and Multicentric Castleman Disease

You may not qualify if:

• Participants who have had anticancer treatment within the last 2 weeks unless the cancer treatment is for a malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial, such as local treatment for carcinoma in situ or hormonal therapy for prostate or breast carcinoma. Toxicity related to prior therapies other than hair loss and neuropathy must have resolved to grade 1.
• KS requiring urgent treatment with cytotoxic chemotherapy.
• Bilirubin (total) \> 1.5 times the upper limit of normal; aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) \> 3 times the upper limit of normal (ULN);
• EXCEPTIONS:
• Total bilirubin \>= 5 mg/dL in participants with Gilbert's syndrome as defined by \> 80% unconjugated
• If the elevated total bilirubin or AST/ALT are due to ART or lymphoma
• ANC \< 1000/mm\^3 and platelets \< 75,000/mm\^3 unless related to lymphoma and/or KSHV-MCD or prior therapy.
• Life-threatening or organ-threatening manifestations of KSHV-MCD.
• Clinically significant cardiac disease, including:
• Myocardial infarction within 6 months of randomization, or an unstable or uncontrolled disease/condition related to or affecting cardiac function (e.g., unstable angina, congestive heart failure, New York Heart Association Class IIIIV).
• Uncontrolled cardiac arrhythmia
• Chronic obstructive pulmonary disease (COPD) with a forced expiratory volume in 1 second (FEV1) \< 50% of predicted normal.
• Moderate or severe persistent asthma within the past 2 years, or uncontrolled asthma of any classification. Note that participants who currently have controlled intermittent asthma or controlled mild persistent asthma are allowed to participate in the study.
• Pregnant people as evaluated by a positive serum or urine beta-human chorionic gonadotropin (Beta-hCG) test
• Participants with severe uncontrolled intercurrent illness, evaluated by history, physical exam and chemistry panel. Participants with severe intercurrent illnesses attributed to lymphoma may be eligible per PI s or designee s discretion.