Reverse Autologous Peripheral Blood Stem Cell Transplantation after Allogeneic Transplantation to Restore Immune Function and Pancytopenia
Authors: Vescio Robert Allen , Linhares Yuliya , Ponec Ryan , Lopiccolo Christopher , Park Amanda , Castillo Rhona , Krishnan Amrita 
Published: December 2023

Despite advances in multiple myeloma treatment the disease remains challenging to treat with repeated relapses in most. For high-risk younger patients, allogeneic transplants are occasionally performed. While curative in some, complications can include the development of opportunistic infections and secondary malignancies. Furthermore, patients relapsing after an allogeneic transplant may have poor bone marrow reserve limiting the ability to use subsequent therapies. We describe two patients who underwent a “reverse” autologous peripheral blood stem cell rescue using stem cells banked prior to allogeneic transplantation. The outcomes were successful and led to full engraftment and correction of their immunodeficiencies and pancytopenia respectively.
Case 1: A 37-year-old woman was diagnosed with multiple myeloma during routine testing for an in-vitro fertilization assessment. She had ISS stage 2 disease and was treated with CyBorD, followed by an autologous stem cell transplantation. Lenalidomide plus dexamethasone was used as maintenance. She relapsed after just one year then progressed through single agent carfilzomib and then bendamustine. After responding to 2 cycles of DCEP she had a 10/10 matched unrelated donor CD34-selected allogeneic transplant. The patient was EBV positive, but the donor was not. Four months post-transplant she developed tonsillar PTLD with a rising EBV DNA titer and was treated with rituximab. Her CD4 count was 46. Her multiple myeloma relapsed thereafter necessitating treatment with daratumumab. She then developed rituximab-resistant monomorphic PTLD which then responded to brentuximab-vedotin and donor lymphocyte infusions. The multiple myeloma relapsed again and was treated with daratumumab + pomalidomide + dexamethasone. After a rising EBV DNA titer, brentuximab-vedotin was restarted but the lymphoma progressed again with a 5 x 3 cm anterior mediastinal mass biopsy proven to be monomorphic PTLD. R-CHOP was given for 4 cycles but resulted in only a partial response. Due to subsequent rapidly symptomatic and progressive disease a decision was made to use high-dose melphalan (200 mg/m2) followed by a reinfusion of her previously collected autologous stem cells to restore her T-cell immunity and hopefully control her lymphoma. She engrafted uneventfully at Day + 12 with chimerism studies showing autologous hematopoiesis and a CD4 count of 856. Her post-transplant course was complicated by renal thrombotic microangiopathy treated successfully with eculizumab. After further myeloma relapses, she is currently alive and well and in remission while on teclistamab over 4 yrs after her 2 nd autologous PBSC transplant. Her lymphoma has resolved.
Case 2: A 37-year-old-male with beta-thalassemia was noted to have an elevated total protein on routine blood testing for a life insurance policy. Work up revealed multiple myeloma with a t(4:14) abnormality and complex cytogenetics. After initial observation he was started on KRD for progressive anemia. A VGPR was obtained and consolidated with an autologous PBSC transplant. He was maintained on Ixazomib+lenalidomide+dexamethasone but relapsed 2 years later with a sacral mass. After progressions though daratumumab+pomalidomide+dexamethasone then carfilzomib and then XRT to a large chest mass followed by DCEP as salvage, he underwent a 9/10 mismatched allogeneic transplant. He developed Grade 2 skin GVH but had disease progression again after just 6 months. Salvage treatment with elotuzumab+pomalidomide+dexamethasone then DCEP and subsequently ciltacabtagene autoleucel were unsuccessful with progression after just 6 weeks from the latter. He was treated again with DCEP but became transfusion dependent after the 2 nd cycle and had progressive disease again. Due to symptomatic myeloma and pancytopenia he underwent a reverse autologous PBSC transplant using banked stem cells. He engrafted uneventfully on Day +11 and despite recurrent multiple myeloma, he is currently in remission while on talquetamab. His beta-thalassemia returned.
These cases demonstrate the ability to reverse an allogeneic transplant successfully using previously stored autologous peripheral blood stem cells. The recovery allowed for resumption of effective anti-cancer treatment that became lifesaving. Whether this approach could correct patients with unrelenting GVH issues should be contemplated as well.