Kidney transplantation in multiple myeloma: patient selection, timing, and post-transplant challenges in the modern therapeutic era.

Kidney involvement is a common and clinically significant complication of multiple myeloma (MM), with a subset of patients progressing to end-stage kidney disease (ESKD). Historically, kidney transplantation was considered contraindicated in MM due to poor prognosis and high relapse rates. However, the introduction of novel anti-myeloma therapies has markedly improved hematologic responses and patient survival, leading to reconsideration of transplantation in this population. This review summarizes current evidence on patient selection, optimal timing, and post-transplant management of kidney transplantation in MM. Candidate selection should be guided by disease biology, depth of hematologic response, and remission durability. Transplantation is preferentially considered in patients achieving at least very good partial response, ideally with minimal residual disease negativity, while timing should be individualized according to cytogenetic risk, remission duration, and overall disease stability. Post-transplant management requires balancing immunosuppression with the competing risks of relapse, infection, and graft rejection. The optimal role of maintenance therapy remains uncertain, particularly given the potential interaction between anti-myeloma agents and allograft immunity. Available evidence, derived mainly from retrospective studies and small cohorts, suggests that patient and graft outcomes in carefully selected MM patients may approach those observed in other causes of ESKD. Although important uncertainties remain, kidney transplantation should be considered a viable treatment option within a multidisciplinary framework. Future studies are needed to refine eligibility criteria, optimize timing, and define long-term management strategies in this evolving population.