Faculty Bibliography

Introduction. Prevention of graft-versus-host disease (GvHD) following allogeneic hematopoietic cell transplantation (AHCT) remains a major challenge. The combination of methotrexate (MTX) and a calcineurin inhibitor has been the standard regimen for prophylaxis in patients receiving matched sibling donor (MSD) or matched unrelated donor (MUD) transplants for the past few decades. However, over 50% of patients undergoing AHCT still develop acute or chronic GvHD or even both, causing high rates of morbidity and mortality. Moreover, calcineurin inhibitors also have untoward toxic side effects. High dose post-transplant cyclophosphamide (PTCy), initially introduced for GvHD prevention in the setting of haploidentical transplantation, has now been studied in MSD and MUD transplants. We adopted a novel approach to prevent GvHD using a short course of PTCy and bortezomib. We hypothesized that such combination is safe and effective and omits the need for calcineurin or m-TOR inhibitors. Study Design. We report the outcomes of a prospective cohort of patients who received PTCy and bortezomib for GvHD prevention following MSD or MUD transplants. Twenty-eight patients were treated in a phase I-II trial and their clinical outcomes were previously reported (al-Homsi AS et al, BBMT 2019). Most of the remaining patients were treated on an extension trial. GvHD prevention consisted of PTCy 50 mg/kg IV on day +3 and +4, and bortezomib 1.3mg/m ² IV 6 hours after transplant and again 72 hours after. Patients receiving MUD transplants also received rabbit ATG (thymoglobulin) 5mg/kg total IV fractionated on day -4 to -2. All patients received peripheral blood grafts and standard supportive care as per Institutional policy. G-CSF was administered routinely until neutrophil engraftment. Results. Fifty-eight patients are included in this analysis. Median age was 60 (range 22-78) years. Fifty-three percent of patients were male. Underlying malignancies consisted of myeloid and lymphoid malignancies in 79.3% and 20.6%, respectively. Acute myeloid leukemia (50%) and myelodysplastic syndromes (24.1%) were the most common diseases. At transplant, disease risk index was low, intermediate, high and very high in 19.0%, 48.3%, 31.0% and 1.7% of patients, respectively. Median Pretransplant Assessment of Mortality Score (PAM) was 16.7 (5.4-29.4). Grafts were from MSD in 24.1% or MUD in 75.9% of patients. Recipient (R)/Donor (D) CMV status at transplant was as follows: R+/D+: 43%; R+/D-: 21%; R-/D+: 14% and R-/D-: 22%. Conditioning regimens consisted of reduced intensity fludarabine and busulfan in all but 2 patients who were conditioned with myeloablative fludarabine and busulfan. Overall, the regimen was remarkably well tolerated. Median times to neutrophil and platelet engraftment were 16 (13-28) and 26 (15-57) days respectively. No patient experienced primary graft failure. CMV and EBV reactivation rates were 46.6% and 24%. Cumulative incidences of grade II-IV and grade III-IV acute GVHD were 35% (95% CI: 22%-47%) and 15% (95% CI: 7%-25%) at day +120, respectively. Cumulative incidence of chronic GvHD was 14% at 1 year. Overall, 34% of patients required immunosuppression with systemic steroids after day +4 either for grade III-IV acute or chronic GvHD. Disease relapse rate was 26%. One-year cumulative incidence of transplant-related mortality was 14% (95% CI: 6%-25%). Median overall survival was 30.7 (95% CI: 15.7-not yet reached) months. One-year overall survival was 72% (95% CI: 57%-82%). One-year composite GvHD (acute and chronic) free and relapse free survival (GRFS) was 41.6% (95% CI: 28.9%-54%). Conclusion. PTCy and bortezomib combination for GvHD prophylaxis following MSD and MUD transplants is well tolerated and effective. It offers an alternative regimen to calcineurin and m-TOR inhibitor-containing regimens and may be preferred in certain settings including patients with limited resources, poor medication compliance, and with impaired renal function. A comparison of this cohort to a matched control group of patients receiving methotrexate and cyclosporine for GvHD prevention is ongoing. Disclosures: Abdul-Hay: Amgen: Membership on an entity's Board of Directors or advisory committees; Servier: Other: Advisory Board, Speakers Bureau; Jazz: Other: Advisory Board, Speakers Bureau; Abbvie: Consultancy; Takeda: Speakers Bureau. Al-Homsi: Celyad: Other: Advisory Board; Daichii Sanyko: Consultancy. OffLabel Disclosure: Cyclophosphamide and Bortezomib are used for GvHD prevention
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Introduction Cytomegalovirus (CMV) infection is one of the most common complication after allogeneic hematopoietic stem-cell transplantation (HSCT) still associated with significant morbidity and mortality. Although pre-emptive therapy (PET) are routinely used in treatment of CMV after SCT, their prophylactic use is limited by clinically unacceptable myelosuppression and nephrotoxicity. Letermovir, available since 2019 in Italy, is the first antiviral agent approved by FDA and EMA which is indicated for the prophylaxis of CMV infection in CMV seropositive (R+) patients undergoing SCT. Presently, cost and drug interactions are the main disadvantages of Letermovir use. We performed a single-center observational retrospective study to evaluate the efficacy of primary Letermovir prophylaxis for CMV infection among high-risk patients (R+) receiving HSCT from serological negative donor (D-). Methods We evaluated a cohort of R+/D- patients transplanted from January 2017 to December 2020 (86/235 transplanted patients): among those eligible for Letermovir prophylaxis (N=70), 29 patients (transplanted after 2019) received Letermovir until day +100, whereas 41 patients (the historical control group transplanted before 2019) received CMV PET only in case of increased viral load (CMV reactivation). Patients unable to take oral therapy at day +7 from HSCT or assuming drugs for concomitant clinical conditions bringing about major pharmacokinetic interaction were excluded (N=16). We compared day +100 and day +200 cumulative incidence of clinically significant CMV infection (CS-CMVi), defined according to drug registration trial: Letermovir discontinuation before day +100, CMV reactivation (CMV-DNAemia leading to PET), CMV tissue invasive disease, disease relapse and death from any causes. Survival functions between groups were estimated by the Kaplan-Meier method and compared using log-rank test. Moreover, the overall survival (OS), disease free survival (DFS), non-relapse mortality (NRM) and cumulative incidence of II-IV grade acute graft-versus-host disease (aGVHD) was compared in the two cohorts. Finally, we analyzed the number of accesses in day hospital from initial discharge to day +180, as an indirect cost-effectiveness evaluation of letermovir prophylaxis. Results No severe adverse events related to the therapy were observed in the letermovir group. Letermovir prophylaxis started at a median of 11 days (range, 5-27) after HSCT. The median duration of Letermovir administration was 89 days (range, 40-113). The only early stop was due to patient death, not related to CMV or drug toxicity. CS-CMVi at day +100 occurred in 13.8% vs 61.0% in letermovir and historical group, respectively (p <0.001). Of note, none of the events in letermovir group was related to CMV reactivation whereas 24/25 in the historical group were. A trend toward lower CS-CMVi in the letermovir group was observed also at day +180 (44,8% vs 65,9%, p =0.080), with 6 late reactivations in patients who received prophylaxis. Moreover, at follow-up one patient in the experimental group and 3 in the control group developed CMV disease. Of note, in vivo T-cell depletion was used in 86% of patients in letermovir and 83% in historical group, and most of the CMV reactivations occurred after development of aGVHD: in 83% and 54% of patients, respectively. No differences in OS and DFS were observed between the two cohorts. Finally, a trend toward lower number of day hospital admissions was shown in patients who received letermovir prophylaxis (median 2 admissions, IQR 0-8, vs median 4.5, IQR 0-16), suggesting higher quality of life and costs reduction. Conclusions Our real-life experience demonstrated the efficacy of Letermovir in reducing the incidence of CMV reactivation. Longer follow-up is needed to clarify advantages in terms of disease-free and overall survival. Further studies are needed to investigate the role of prophylaxis beyond day 100 in high risk patients, such as those who receive a T-depleted transplant or who develop aGVHD. The role of Letermovir prophylaxis on immuno-reconstitution and its cost-effectiveness remains to be evaluated. Disclosures: Marco: Jazz: Consultancy; Insight,: Consultancy; Janssen: Consultancy. Ferrero: EUSA Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Research Funding, Speakers Bureau; Morphosys: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Clinigen: Membership on an entity's Board of Directors or advisory committees; Servier: Speakers Bureau.
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INTRODUCTION/UNASSIGNED:Chimeric antigen receptor (CAR)-T-cell therapy is a new treatment for patients with hematologic malignancies in which other therapies have failed. AREAS COVERED/UNASSIGNED:The review provides an overview for recognizing and managing the most acute toxicities related to CAR-T cells. EXPERT OPINION/UNASSIGNED:The development of immune-mediated toxicities is a common challenge of CAR-T therapy. The mechanism that determines this toxicity is still unclear, although an unfavorable tumor microenvironment and a pro-inflammatory state put patients at risk. The monitoring, diagnosis, and treatment of post-CAR-T toxicities must be determined and based on international guidelines and internal clinical practice. It is urgent to identify biomarkers that can identify patients at greater risk of developing complications. The adoption of consistent grading criteria is necessary to improve toxicity management strategies continually. The first-line therapy consists of supportive care and treatment with tocilizumab or corticosteroids. An early start of cytokine blockade therapies could mitigate toxicity. The plan will include cytokine release prophylaxis, a risk-adapted treatment, prevention of on-target/off-tumor effect, and a switch on/off CAR-T approach.

Chimeric antigen receptor (CAR) T cells (CAR-T) have dramatically changed the treatment landscape of B-cell malignancies, providing a potential cure for relapsed/refractory patients. Long-term responses in patients with acute lymphoblastic leukemia and non Hodgkin lymphomas have encouraged further development in myeloma. In particular, B-cell maturation antigen (BCMA)-targeted CAR-T have established very promising results in heavily pre-treated patients. Moreover, CAR-T targeting other antigens (i.e., SLAMF7 and CD44v6) are currently under investigation. However, none of these current autologous therapies have been approved, and despite high overall response rates across studies, main issues such as long-term outcome, toxicities, treatment resistance, and management of complications limit as yet their widespread use. Here, we critically review the most important pre-clinical and clinical findings, recent advances in CAR-T against myeloma, as well as discoveries in the biology of a still incurable disease, that, all together, will further improve safety and efficacy in relapsed/refractory patients, urgently in need of novel treatment options.

We have used a non-myeloablative conditioning regimen for allogeneic hematopoietic cell transplantation for the past twenty years. During that period, changes in clinical practice have been aimed at reducing morbidity and mortality from infections, organ toxicity, and graft-versus-host disease. We hypothesized that improvements in clinical practice led to better transplantation outcomes over time. From 1997-2017, 1,720 patients with hematologic malignancies received low-dose total body irradiation +/- fludarabine or clofarabine before transplantation from HLA-matched sibling or unrelated donors, followed by mycophenolate mofetil and a calcineurin inhibitor ± sirolimus. We compared outcomes in three cohorts by year of transplantation: 1997 +/- 2003 (n=562), 2004 +/- 2009 (n=594), and 2010 +/- 2017 (n=564). The proportion of patients ≥60 years old increased from 27% in 1997 +/- 2003 to 56% in 2010-2017, and with scores from the Hematopoietic Cell Transplantation Comborbidity Index of ≥3 increased from 25% in 1997 +/- 2003 to 45% in 2010 +/- 2017. Use of unrelated donors increased from 34% in 1997 +/- 2003 to 65% in 2010-2017. When outcomes from 2004 +/- 2009 and 2010-2017 were compared to 1997 +/- 2003, improvements were noted in overall survival (P=.0001 for 2004-2009 and P <.0001 for 2010-2017), profression-free survival (P=.002 for 2004-2009 and P <.0001 for 2010 +/- 2017), non-relapse mortality (P<.0001 for 2004 +/- 2009 and P <.0001 for 2010 +/- 2017), and in rates of grades 2 +/- 4 acute and chronic graft-vs.-host disease. For patients with hematologic malignancies who underwent transplantation with non-myeloablative conditioning, outcomes have improved during the past two decades. Trials reported are registered under ClinicalTrials.gov identifiers: NCT00003145, NCT00003196, NCT00003954, NCT00005799, NCT00005801, NCT00005803, NCT00006251, NCT00014235, NCT00027820, NCT00031655, NCT00036738, NCT00045435, NCT00052546, NCT00060424, NCT00075478, NCT00078858, NCT00089011, NCT00104858, NCT00105001, NCT00110058, NCT00397813, NCT00793572, NCT01231412, NCT01252667, NCT01527045.

Background: Cytomegalovirus (CMV) infection is one of the most common complication after allogeneic hematopoietic stem-cell transplantation (HSCT) and remains associated with significant morbidity. Letermovir is an antiviral drug approved for prevention of CMV infection in seropositive HSCT recipients (R+), inhibiting the CMVterminase complex and thus acting in a different way than other standard approved antiviral drugs. In Italy, Letermovir has been available since 2019.
Method(s):We conducted a single-center cohort observational retrospective study, analysing 107 patients at highest risk of CMV infection according to recipient positive/donor negative (R+/D-) CMV serostatus, transplanted between January 2015 and April 2020 at our Center. Patients unable to take oral therapy at day +7 from HSCT or assuming drugs for concomitant clinical conditions bringing about major pharmacokinetic interaction were excluded. Nineteen of them received primary Letermovir prophylaxis (starting within day +28, up to day +100), whereas 74 patients did not (historical control group). In both groups, patients underwent pre-emptive therapy (PET) strategy according to twice weekly monitoring of blood CMV-DNA levels through PCR analysis. We compared cumulative incidence of clinically significant CMV infection (CS-CMVi), defined as CMV reactivation (CMV-DNAemia leading to PET) or CMV tissue invasive disease at day +100 and day +200. Patients who discontinued drug assumption before day +100 or had missing endpoint data at day +100 were imputed as having a primary endpoint event, according to the drug registration trial. Survival functions were estimated by the Kaplan-Meier method and compared using log-rank test.
Result(s): Letermovir prophylaxis started at a median of 11 days (range, 5-27) after HSCT. The median duration of Letermovir administration was 89 days (range, 40-113). The only early stop was due to patient death, not related to CMV or drug toxicity. None of the 19 patients in Letermovir group experienced CMV reactivation at day +100, compared to 51 in the historical group. Of note, 83% of patients receiving prophylaxes developed graft-versus-host disease (GVHD) before CS-CMVi. Overall, at day +100 CS-CMVi occurred in 5.3% and 71.6% of patients in Letermovir group and historical control group, respectively (p <.001). A trend toward lower CS-CMVi was also observed in the Letermovir group at day +200 (63,2% vs 81,1%, p=.0956). Median time to CSCMVi was +147 and +44 days after HSCT in Letermovir group and historical control group, respectively. One patient in Letermovir group and 4 in the historical one developed CMV tissue invasive disease. No difference in mortality was observed between the two groups, even if a longer follow-up period is needed.
Conclusion(s): Our experience demonstrated the efficacy of Letermovir in a real-world setting for CMV prevention in the first 14 weeks after HSCT. Further studies are needed to establish the cost-effectiveness of Letermovir primary prophylaxis compared to PET approach, and the role of extension of Letermovir beyond day +100 in high-risk subgroup

A mismatched unrelated (MMUD) donor represents an alternative therapeutic option for patients who need allogeneic hematopoietic cell transplantation (allo-HCT) and do not have a human leukocyte antigen (HLA) matched donor. We studied outcomes of patients with acute leukemia transplanted from ≥2 HLA allele MMUD. The study population consisted of 465 patients. The median follow-up period was 63 and 75 months in the AML and ALL groups, respectively. The incidence of grade II-IV and grade III-IV acute (a) graft-versus-host disease (GVHD) during the first 100 days was 37% and 16%, respectively. Total and extensive chronic (c) GVHD rates at 2 years were 38% and 17%, respectively. In the entire population, the 5-year relapse incidence (RI), non-relapse mortality (NRM), leukemia-free survival (LFS), overall survival and refined GVHD-free, relapse-free survival (GRFS) was 33%, 31%, 37%, 41%, and 27%, respectively. In the multivariate analysis, HLA-DR mismatch was a poor prognostic factor, giving a significantly higher NRM [hazard ratio (HR), 1.67, p = 0.02]; poorer LFS (HR, 1.42, p = 0.03); OS (HR, 1.46, p = 0.03) and higher aGVHD grade II-IV (HR, 1.46, p = 0.05). In this study, allo-HCT from ≤6/8 HLA allele MMUD in acute leukemia patients resulted in acceptable LFS and refined GRFS. HLA-DR mismatch was a poor prognostic factor.

Endothelial cell (EC) dysfunction causes a number of early and life-threatening post hematopoietic stem cell transplant (HCT) complications that result in a rapid clinical decline. The main early complications are graft-vs.-host disease (GVHD), transplant associated thrombotic microangiopathy (TA-TMA), and sinusoidal obstruction syndrome (SOS). Post-HCT endothelial dysfunction occurs as a result of chemotherapy, infections, and allogeneic reactivity. Despite major advances in transplant immunology and improvements in supportive care medicine, these complications represent a major obstacle for successful HCT. In recent years, different biomarkers have been investigated for early detection of post-transplant endothelial cell dysfunction, but few have been validated. In this review we will define GVHD, TA-TMA and SOS, summarize the current data available in HCT biomarker research and identify promising biomarkers for detection and diagnosis of early HCT complications.

Even with high-dose post-transplant cyclophosphamide (PT-Cy) which was initially introduced for graft-versus-host disease (GvHD) prevention in the setting of HLA-haploidentical transplantation, both acute and chronic GvHDs remain a major clinical challenge. Despite improvements in the understanding of the pathogenesis of both acute and chronic GvHDs, reliable biomarkers that predict their onset have yet to be identified. We recently studied the potential correlation between extracellular vesicles (EVs) and the onset of acute (a)GvHD in transplant recipients from related and unrelated donors. In the present study, we further investigated the role of the expression profile of membrane proteins and their microRNA (miRNA) cargo (miRNA100, miRNA155, and miRNA194) in predicting the onset of aGvHD in haploidentical transplant recipients with PT-Cy. Thirty-two consecutive patients were included. We evaluated the expression profile of EVs, by flow cytometry, and their miRNA cargo, by real-time PCR, at baseline, prior, and at different time points following transplant. Using logistic regression and Cox proportional hazard models, a significant association between expression profiles of antigens such as CD146, CD31, CD140a, CD120a, CD26, CD144, and CD30 on EVs, and their miRNA cargo with the onset of aGvHD was observed. Moreover, we also investigated a potential correlation between EV expression profile and cargo with plasma biomarkers (e.g., ST2, sTNFR1, and REG3a) that had been associated with aGVHD previously. This analysis showed that the combination of CD146, sTNFR1, and miR100 or miR194 strongly correlated with the onset of aGvHD (AUROC >0.975). A large prospective multicenter study is currently in progress to validate our findings.