Treatment regimen and response: Luis was considered ineligible for stem-cell transplantation owing to his age (≥79 years). Initial therapy consisted of daratumumab plus lenalidomide (25 mg/day, days 1-21) and dexamethasone (20 mg/week). Zoledronic acid has been administered monthly since diagnosis to reduce pain and prevent further skeletal events.

Luis achieved very good partial response (VGPR) after 6 cycles of DRd, showing a 90% reduction in M-protein levels.

Current presentation: Luis says that his back pain and body aches have improved over the past months. However, he complains of fatigue, weakness, severe paresthesia, and balance problems. He is also experiencing insomnia and irritability. His family reports that Luis needs assistance with tasks of daily functioning and self-care. His ECOG performance status score is 2.

Laboratory results show that Luis has maintained VGPR. Chemistry tests reveal mild hypercalcemia (10.4 mg/dL). The creatinine clearance rate has remained stable (CrCl: 90 mL/min). Hematology tests indicate anemia (Hb: 8.2 g/dL), neutropenia (ANC: 0.8 x 10/L), and moderate thrombocytopenia (60,000/mcL).

Positron emission tomography shows resolution of metabolic activity in the osteolytic lesions, indicated by a reduction in SUV compared to previous scans.