Abstract / Summary
Bispecific T-cell engagers are highly effective in refractory multiple myeloma, but their use after solid organ transplantation raises interdependent concerns regarding allograft rejection from pharmacologic T-cell activation, reduced efficacy due to T-cell-directed immunosuppression, and compounded infection risk from concurrent maintenance immunosuppression and bispecific-induced plasma cell depletion. We report the first known use of elranatamab in a kidney transplant recipient, treated for refractory IgG kappa myeloma with light-chain deposition disease. Acute toxicity was limited to grade 1 cytokine release syndrome. She achieved sustained serologic complete response, with normalization of free light chains within two weeks and conversion to negative serum immunofluorescence. Standard immunosuppression with tacrolimus and mycophenolate was maintained, with only two brief dose-reductions during acute infection. Grade 3 pneumonia requiring admission occurred at the IgG nadir before immunoglobulin replacement began; no further infection occurred during the remaining treatment period, however post-treatment she experienced two episodes of grade 2 tonsillitis requiring antibiotics and grade 3 infectious colitis occurring 8 months post-treatment discontinuation despite ongoing immunoglobulin administration. Therapy was stopped at 4.5 months to limit infection risk. At 14.5 months post-initiation and 10 months off treatment, she continues to have serologic complete response and stable allograft function. This case suggests that time-limited bispecific therapy with standardized infection and graft surveillance may be feasible in selected patients with relapsed multiple myeloma following kidney transplant.