Old age: the crown of life, our play's last act. Question and answers on older patients undergoing allogeneic hematopoietic cell transplantation.

PURPOSE OF REVIEW: Several studies showed that age alone should not be used as an arbitrary parameter to exclude patients from allogeneic hematopoietic cell transplantation (HCT). The accessibility to allogeneic HCT programs for older patients with hematological diseases is growing up constantly. The Center for International Blood and Marrow Transplant Research has recently shown that over 30% of allogeneic HCT recipients are at least 60 years old and that nearly 4% are aged 70 or more. Historically, the use of allogeneic HCT among elderly patients has been limited by age restrictions, reflecting physicians' concerns regarding prohibitive transplant-related mortality and HCT-associated morbidity. RECENT FINDINGS: The introduction of reduced intensity/toxicity conditioning regimens has allowed transplant Centers to carry out allogeneic HCT on patients previously considered not ideal candidates. The integration of specific risk scores could lead to better capture mental and physical frailties of older patients. Older adults less frequently have available medically fit siblings, able to donate, so, unrelated donors, familial haploidentical donors or umbilical cord blood grafts could potentially abrogate such a difficulty, allowing the curative potential of allogeneic HCT. SUMMARY: The appropriate assessing of allogeneic HCT feasibility for elderly patients should be the resonate application of different clinical and biological principles.

Role of serum-free light chain assay for defining response and progression in immunoglobulin secretory multiple myeloma.

The International Myeloma Working Group (IMWG) guidelines recommend using electrophoresis and immunofixation to define response and progressive disease (PD) in immunoglobulin (Ig) secretory multiple myeloma (Ig-MM), whereas the role of serum-free light chain (sFLC) is controversial. We retrospectively analyzed the value of adding sFLC assays in the definition of response and PD according to IMWG criteria in 339 Ig-MM patients treated with a first-line novel agent-based therapy (median follow-up 54 months). sFLC PD was defined according to conventional criteria plus increased sFLC levels, or sFLC escape (sFLCe); progression/sFLCe-free survival (ePFS) was the time from the start of treatment to the date of first PD or sFLCe, or death; overall survival after PD/sFLCe (OS after Pe) was the time from first PD or sFLCe to the date of death. 148 (44%) patients achieved a complete response and 198 (60%) a normal sFLC ratio (sFLCR). sFLCR normalization was an independent prognostic factor for extended PFS (HR = 0.46, p = 0.001) and OS (HR = 0.47, p = 0.006) by multivariable analysis. 175 (52%) patients experienced PD according to the IMWG criteria, whereas 180 (53%) experienced PD or sFLCe. Overall, a sFLCe was observed in 31 (9%) patients. Median PFS and ePFS were both equal to 36 (95% CI = 32-42, and 32-40, respectively) months. sFLC PD adversely affected the OS after Pe compared to PD with increasing monoclonal Ig only (HR = 0.52, p = 0.012). Our results support the inclusion of the sFLC assay for defining response and PD in Ig-MM.

CAR+ extracellular vesicles predict ICANS in patients with B cell lymphomas treated with CD19-directed CAR T cells.

BACKGROUND: Predicting Immune-effector Cell Associated Neurotoxicity Syndrome (ICANS) in patients infused with Chimeric Antigen Receptor T cells (CAR-T) is still a conundrum. This complication, thought to be consequent to CAR-T cell activation, arises a few days after infusion, when circulating CAR-T cells are scarce and specific CAR-T cell-derived biomarkers are lacking. METHODS: Human CD19.CAR-T cells were generated to gain insight into CAR+ extracellular vesicle (CAR+EV) release upon target engagement. A prospective cohort of 100 B-cell lymphoma patients infused with approved CD19.CAR-T cell products (axi-cel, brexu-cel and tisa-cel) was assessed for plasma CAR+EVs as potential biomarkers of in vivo CD19.CAR-T cell activation and predictors of ICANS. Human induced pluripotent stem cells (iPSCs)-derived neural cells were used as a model for CAR+EV-induced neurotoxicity. RESULTS: In vitro, exosome-like CAR+EVs were released by CD19.CAR-T cells upon target engagement. In vivo, CAR+EVs were detectable as early as 1 hour in the plasma of patients. A concentration > 132.8 CAR+EVs/µl at hour +1 or > 224.5 CAR+EVs/µl at day +1 predicted ICANS in advance of 4 days, with a sensitivity up to 96.55% and a specificity up to 80.36%, outperforming other potential ICANS predictors. Enolase 2 (ENO2+) nanoparticles were released by iPSCs-derived neural cells upon CAR+EVs exposure and were increased in the plasma of ICANS patients. CONCLUSIONS: These results convey that plasma CAR+EVs are an immediate signal of CD19.CAR-T cell activation, are suitable predictors of neurotoxicity, and may be involved in ICANS pathogenesis. TRIAL REGISTRATION: NCT04892433, NCT05807789.

Long term follow-up of humoral and cellular response to mRNA-based vaccines for SARS-CoV-2 in patients with active multiple myeloma.

Long-term kinetics of antibody (Ab) and cell-mediated immune (CMI) response to full anti-SARS-CoV-2 vaccine schedule and booster doses in Multiple Myeloma (MM) patients remain unclear. We prospectively evaluated Ab and CMI response to mRNA vaccines in 103 SARS-CoV-2-naïve MM patients (median age 66, 1 median prior line of therapy) and 63 health-workers. Anti-S-RBD IgG (Elecsys®assay) were measured before vaccination and after 1 (T1), 3 (T3), 6 (T6), 9 (T9) and 12 (T12) months from second dose (D2) and 1 month after the introduction of the booster dose (T1D3). CMI response (IGRA test) was evaluated at T3 and T12. Fully vaccinated MM patients displayed high seropositivity rate (88.2%), but low CMI response (36.2%). At T6 the median serological titer was halved (p=0.0391) in MM patients and 35% reduced (p=0.0026) in controls. D3 (94 patients) increased the seroconversion rate to 99% in MM patients and the median IgG titer in both groups (up to 2500 U/mL), maintained at T12. 47% of MM patients displayed a positive CMI at T12 and double-negativity for humoral and CMI (9.6% at T3) decreased to 1%. Anti-S-RBD IgG level ≥346 U/mL showed 20-times higher probability of positive CMI response (OR 20.6, p<0.0001). Hematological response ≥CR and ongoing lenalidomide maintenance enhanced response to vaccination, hindered by proteasome inhibitors/anti-CD38 monoclonal antibodies. In conclusion, MM elicited excellent humoral, but insufficient cellular responses to anti-SARS-CoV-2 mRNA vaccines. Third dose improved immunogenicity renewal, even when undetectable after D2. Hematological response and ongoing treatment at vaccination were the main predictive factors of vaccine immunogenicity, emphasizing the role of vaccine response assessment to identify patients requiring salvage approaches.

The prevention of disease relapse after allogeneic hematopoietic cell transplantation in acute myeloid leukemia.

Disease relapse represents by far the most frequent cause of hematopoietic cell transplantation (HCT) failure. Patients with acute leukemia suffering relapse after HCT have limited conventional treatment options with little possibility of cure and represent, de facto, suitable candidates for the evaluation of novel cellular and biological-based therapies. Donor lymphocyte infusions (DLI) has been one of the first cellular therapies adopted to treat post HCT relapse of acute leukemia patients and still now, it is widely adopted in preemptive and prophylactic settings, with renewed interest for manipulated cellular products such as NK-DLI. The acquisition of novel biological insights into pathobiology of leukemia relapse are translating into the clinic, with novel combinations of target therapies and novel agents, helping delineate new therapeutical landscapes. Hypomethylating agents alone or in combination with novel drugs demonstrated their efficacy in pre-clinical models and controlled trials. FLT3 inhibitors represent an essential therapeutical instrument incorporated in post-transplant maintenance strategies. The Holy grail of allogeneic transplantation lies in the separation of graft-vs.-host disease from graft vs. tumor effects and after more than five decades, is still the most ambitious goal to reach and many ways to accomplish are on their way.

Pre-transplant CD69+ extracellular vesicles are negatively correlated with active ATLG serum levels and associate with the onset of GVHD in allogeneic HSCT patients.

Graft versus host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Rabbit anti-T lymphocyte globulin (ATLG) in addition to calcineurin inhibitors and antimetabolites is a suitable strategy to prevent GVHD in several transplant settings. Randomized studies already demonstrated its efficacy in terms of GVHD prevention, although the effect on relapse remains the major concern for a wider use. Tailoring of ATLG dose on host characteristics is expected to minimize its side effects (immunological reconstitution, relapse, and infections). Here, day -6 to day +15 pharmacokinetics of active ATLG serum level was first assayed in an explorative cohort of 23 patients by testing the ability of the polyclonal serum to bind antigens on human leukocytes. Significantly lower levels of serum active ATLG were found in the patients who developed GVHD (ATLG_AUCCD45: 241.52 ± 152.16 vs. 766.63 +/- 283.52 (µg*day)/ml, p = 1.46e-5). Consistent results were obtained when the ATLG binding capacity was assessed on CD3+ and CD3+/CD4+ T lymphocytes (ATLG_AUCCD3: 335.83 ± 208.15 vs. 903.54 ± 378.78 (µg*day)/ml, p = 1.92e-4; ATLG_AUCCD4: 317.75 ± 170.70 vs. 910.54 ± 353.35 (µg*day)/ml, p = 3.78e-5. Concomitantly, at pre-infusion time points, increased concentrations of CD69+ extracellular vesicles (EVs) were found in patients who developed GVHD (mean fold 9.01 ± 1.33; p = 2.12e-5). Consistent results were obtained in a validation cohort of 12 additional ATLG-treated HSCT patients. Serum CD69+ EVs were mainly represented in the nano (i.e. 100 nm in diameter) EV compartment and expressed the leukocyte marker CD45, the EV markers CD9 and CD63, and CD103, a marker of tissue-resident memory T cells. The latter are expected to set up a host pro-inflammatory cell compartment that can survive in the recipient for years after conditioning regimen and contribute to GVHD pathogenesis. In summary, high levels of CD69+ EVs are significantly correlated with an increased risk of GVHD, and they may be proposed as a tool to tailor ATLG dose for personalized GVHD prevention.

Ceftolozane-Tazobactam Treatment of Hypervirulent Multidrug Resistant Pseudomonas aeruginosa Infections in Neutropenic Patients.

The effectiveness of ceftolozane/tazobactam for the treatment of infections in neutropenic patients caused by hypervirulent multidrug-resistant (MDR) Pseudomonas aeruginosa has not been previously reported. We identified seven cases of MDR P. aeruginosa infection in neutropenic patients over a four-month period within the same hematology ward. Four cases were associated with rapid progression despite piperacillin-tazobactam or meropenem therapy, and three patients developed sepsis or extensive skin/soft tissue necrosis. In three of the four cases, patients were empirically switched from meropenem to ceftolozane/avibactam before carbapenem susceptibility test results were available, and all four patients underwent extensive surgical debridement or amputation of affected tissues and survived. Further investigation revealed a common bathroom source of MDR P. aeruginosa clonal subtypes ST175 and ST235 that harbored genes for type III secretion system expression and elaboration of ExoU or ExoS exotoxin. We conclude that ceftolozane/tazobactam plus early source control was critical for control of rapidly progressing skin and soft infection in these neutropenic patients caused by highly virulent ST175 and ST235 clones of MDR P. aeruginosa.