Very scarce data exist about outcomes of relapsed multiple myeloma patients who have failed proteasome inhibitor, immunomodulatory drug, anti‐CD38 monoclonal antibody and therapies targeting B‐cell maturation antigen (BCMA) (Quad‐class exposed [QCE]). In this retrospective single‐centre study, we determined progression‐free survival (PFS) and overall survival (OS) from anti‐BCMA failure in 45 QCE patients. Seven (16%) patients received antibody‐drug conjugate, 20 (44%) bispecific antibodies and 18 (40%) CAR‐T cell. Thirty patients (67%) received ≥1 subsequent line of treatment. PFS was 4.4 months (95% CI = 2.4–12.5) and OS 6.3 months (95% CI = 3.9–14.4). Having an adverse prognosis, QCE myeloma patients remain an unmet medical need.