Hematopoietic Cell Transplantation: Practice Predictions for the Year 2023

Diagnosis and Management of Adult Malignancy-Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe, dysregulated inflammation driven by the inability of T cells to clear an antigenic target. When associated with malignancy (mHLH), the HLH syndrome is typically associated with extremely poor survival. Here, we review the diagnosis of secondary HLH (sHLH) syndromes in adults, with emphasis on the appropriate workup and treatment of mHLH. At present, the management of HLH in adults, including most forms of mHLH, is based on the use of corticosteroids and etoposide following the HLH-94 regimen. In some cases, this therapeutic approach may be cohesively incorporated into malignancy-directed therapy, while in other cases, the decision about whether to treat HLH prior to initiating other therapies may be more complicated. Recent studies exploring the efficacy of other agents in HLH, in particular ruxolitinib, offer hope for better outcomes in the management of mHLH. Considerations for the management of lymphoma-associated mHLH, as well as other forms of mHLH and immunotherapy treatment-related HLH, are discussed.

Umbilical cord blood: an undervalued and underutilized resource in allogeneic hematopoietic stem cell transplant and novel cell therapy applications

PURPOSE OF REVIEW

The purpose of this review is to primarily discuss the unwarranted decline in the use of umbilical cord blood (UCB) as a source of donor hematopoietic stem cells (HSC) for hematopoietic cell transplantation (HCT) and the resulting important implications in addressing healthcare inequities, and secondly to highlight the incredible potential of UCB and related birthing tissues for the development of a broad range of therapies to treat human disease including but not limited to oncology, neurologic, cardiac, orthopedic and immunologic conditions.

RECENT FINDINGS

When current best practices are followed, unrelated donor umbilical cord blood transplant (CBT) can provide superior quality of life-related survival compared to other allogeneic HSC donor sources (sibling, matched or mismatched unrelated, and haploidentical) through decreased risks of relapse and chronic graft vs. host disease. Current best practices include improved UCB donor selection criteria with consideration of higher resolution human leukocyte antigen (HLA) typing and CD34+ cell dose, availability of newer myeloablative but reduced toxicity conditioning regimens, and rigorous supportive care in the early posttransplant period with monitoring for known complications, especially related to viral and other infections that may require intervention. Emerging best practice may include the use of ex vivo expanded single-unit CBT rather than double-unit CBT (dCBT) or 'haplo-cord' transplant, and the incorporation of posttransplant cyclophosphamide as with haploidentical transplant and/or incorporation of novel posttransplant therapies to reduce the risk of relapse, such as NK cell adoptive transfer. Novel, non-HCT uses of UCB and birthing tissue include the production of UCB-derived immune effector cell therapies such as unmodified NK cells, chimeric antigen receptor-natural killer cells and immune T-cell populations, the isolation of mesenchymal stem cells for immune modulatory treatments and derivation of induced pluripotent stem cells haplobanks for regenerative medicine development and population studies to facilitate exploration of drug development through functional genomics.

SUMMARY

The potential of allogeneic UCB for HCT and novel cell-based therapies is undervalued and underutilized. The inventory of high-quality UCB units available from public cord blood banks (CBB) should be expanding rather than contracting in order to address ongoing healthcare inequities and to maintain a valuable source of cellular starting material for cell and gene therapies and regenerative medicine approaches. The expertise in Good Manufacturing Practice-grade manufacturing provided by CBB should be supported to effectively partner with groups developing UCB for novel cell-based therapies.

ASTCT Committee on Practice Guidelines Survey on Evaluation & Management of Diffuse Large B-cell Lymphoma after Failure of Chimeric Antigen Receptor T Cell Therapy (CAR-T) Therapy

Chimeric antigen receptor T-cell therapy (CAR-T) is a major advance in managing aggressive relapsed or refractory B-cell lymphomas; however, relapses are frequent and pose a major therapeutic challenge. There is substantial variability across transplantation and cellular therapy programs in assessing and managing post-CAR-T failures. The American Society for Transplantation and Cellular Therapy Committee on Practice Guidelines conducted an online cross-sectional survey between August 2021 and October 2021 to determine the U.S. lymphoma and transplantation and cellular therapy physicians' practice patterns for the detection and diagnosis of CAR-T failure, as well as management strategies for diffuse large B-cell lymphoma in this particular setting. E-mail surveys were sent to 901 potential participants, of which 174 (19%) completed the survey. Responders were mainly White (51.2%), male (70.7%), and with >10 years of practice experience (51.2%). Overall, 87% of the responders were affiliated with university/teaching centers; 54.6% had general oncology practices, and 45.4% had lymphoma-focused transplantation/cellular therapy practices. The most common periods to perform surveillance scans were at 3 months and 12 months after CAR-T infusion. Overall, 88.5% of responders would often or always consider a biopsy to confirm relapse and 89% would routinely check for the persistence of the antigen targeted by the CAR (e.g., CD19 in the case of CD19 CAR-T). The most popular first salvage regimen for relapse or progression was an alternate CAR-T therapy (dual or alternate target) regardless of CD19 positivity. Twenty-seven percent of responders chose this regimen for CD19 positive relapse, whereas 31% of responders did so for CD19 negative relapse. Overall, 88.5% of responders favored consolidative allogeneic hematopoietic cell transplantation after response to salvage, whereas 51.2% of physicians would consider autologous hematopoietic cell transplantation in transplantation-naïve patients. There is substantial cross-center variation in surveillance, diagnosis, and management of CAR-T failure. Prospective clinical trials evaluating novel agents in this setting are urgently needed to identify best management strategies.

Updated Trends in Hematopoietic Cell Transplantation in the United States with an Additional Focus on Adolescent and Young Adult Transplantation Activity and Outcomes

Hematopoietic cell transplantation (HCT) has been successfully used to treat many malignant and nonmalignant conditions. As supportive care, donor selection, and treatment modalities evolve, documenting HCT trends and outcomes is critical. This report from the Center for International Blood and Marrow Transplant Research (CIBMTR) provides an update on current transplantation activity and survival rates in the United States. Additional data on the use and outcomes of HCT in the adolescent and young adult (AYA) population are included. AYA patients more frequently receive peripheral blood stem cell grafts than pediatric patients, which may reflect differences in practice in pediatric versus adult treatment centers. The proportions of donor types also differ those in adult and pediatric populations. Outcomes for patients in the AYA age range are similar to those of pediatric patients for acute myelogenous leukemia but worse for acute lymphoblastic leukemia. Outcomes for both leukemias are better in AYA patients compared with older adults. Comparing the time periods 2000 to 2009 and 2010 to 2019 revealed significant improvement in overall survival across the age spectrum, but the greatest improvement in the AYA age group.

New cancer therapies. Are haematopoietic cell transplants a dead duck?

Recent therapy advances for haematological cancers including new drugs and targeted and immune therapies raise the question whether there is a future for haematopoietic cell transplants. Although encouraging, the survival improvements achieved with these new modalities in persons who might otherwise receive a transplant are modest. Furthermore, these modalities are likely to be complementary, not competitive. For example, randomised trials in multiple myeloma, the most common transplants, indicate an ongoing role for transplant despite new anti-myeloma drugs. Targeted therapies in myeloid cancers are estimated to be effective in only about 10 percent of persons with these cancers. The potential impact of current immune therapies on transplant activity is also limited because: (1) they predominately target B-cell rather than myeloid cancers; (2) many successful immune therapy recipients subsequently receive a transplant; (3) considerable data indicate much of the efficacy of allotransplants results from allogeneic rather than cancer-specific immunity not expected to operate with current immune therapies; and (4) they are at an early development stage with unknown long-term safety and efficacy. These data suggest an ongoing role for haematopoietic cell transplants in diverse haematological and genetic disorders.