Successful treatment with daratumumab, lenalidomide, and dexamethasone therapy followed by autologous stem cell transplantation for newly diagnosed polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome: a case report

Background Transplant-eligible patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome are treated with induction therapy and autologous stem cell transplantation. Conventional induction therapies may exacerbate neuropathy and a high rate of disease progression within 5 years. Furthermore, only 50% of patients are able to walk independently after the therapies. Daratumumab, lenalidomide, and dexamethasone therapy has been reported as a less neurotoxic, highly effective therapy for patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome who are ineligible for transplant or whose syndrome is relapsed/refractory, but no reports have provided data from untreated transplant-eligible patients. Case presentation A 34-year-old Japanese woman displayed weakness, pain and edema in the lower limbs, decreased grip strength, amenorrhea, and abdominal distention. She was unable to walk independently. The patient was diagnosed with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome and performed four courses of daratumumab, lenalidomide, and dexamethasone therapy, which enabled her to walk independently and did not exacerbate the neuropathy. Hematopoietic stem cells were collected using plerixafor and filgrastim in combination. Autologous stem cell transplantation was performed with high-dose melphalan. At 3-month post-transplantation follow-up, most of her clinical symptoms had disappeared. Conclusions Daratumumab, lenalidomide, and dexamethasone therapy followed by autologous stem cell transplantation may be more effective than conventional therapy for newly diagnosed polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome. Although there was concerns that daratumumab, lenalidomide, and dexamethasone therapy might lead to poor mobilization of hematopoietic stem cells, this was overcome with the combination of plerixafor and filgrastim. The benefit of daratumumab, lenalidomide, and dexamethasone as induction therapy prior to autologous stem cell transplantation should be confirmed in future clinical trials.