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Rao, Uttam K.

0000-0002-2427-3076

Mayo Clinic

St David's Medical Center

Citations 5

Phase II Study of post transplant cyclophosphamide-based graft versus host disease prophylaxis after HLA-mismatched unrelated donor transplantation and reduced intensity conditioning: Results from the NMDP-sponsored access expansion Study
Bo‐Subait, Stephanie, Logan, Brent R. , Leckrone, Erin , Smith, Sarah , Stefanski, Heather, Malmberg, Craig, Modi, Dipenkumar , Meade, Javier Bolaños, Rao, Uttam K. , Milner, Jordan , Jamieson, Katarzyna , Carrum, George, Kosuri, Satyajit, Cook, Rachel J. , Ballen, Karen K. , Loren, Alison W. , Arai, Sally , Choi, Sung Won , Shaw, Bronwen E. , Larkin, Karilyn , Gooptu, Mahasweta , Malki, Monzr M. Al , Auletta, Jeffery J. , Spellman, Stephen R. , Askar, Medhat , Cusatis, Rachel , Khimani, Farhad , Hamadani, Mehdi , Maiers, Martin , Stanek, Joseph , Abboud, Ramzi , Dholaria, Bhagirathbhai , Hogan, William J. , Reshef, Ran , Qayed, Muna , Broglie, Larisa , Devine, Steven M. , Jiménez, Antonio , Shaffer, Brian C.

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 4232-4232

10.1182/blood-2025-4232 Get It

Abstract Allogeneic hematopoietic cell transplantation (HCT) using an HLA mismatched unrelated donor (MMUD) with calcineurin inhibitor-based graft versus host disease (GVHD) prophylaxis results in increased incidence of non-relapse mortality (NRM) and lower survival compared to matched donor HCT. The NMDP sponsored 15-MMUD study demonstrated that post-transplant cyclophosphamide (PTCy)-based prophylaxis following bone marrow derived MMUD HCT resulted in reduced incidence of GVHD and favorable survival. Because marrow grafts can be difficult to procure and vary in quality, we conducted a phase II, prospective, multicenter study to evaluate PTCy-based GVHD prophylaxis in adult recipients of MMUD using peripheral blood stem cell (PBSC) allografts. The primary study aim was to estimate the probability of one-year overall survival (OS) post HCT. Secondary aims were to assess other key clinical endpoints and determine the rate of severe infections. Initial results of the first 70 recipients who received reduced intensity conditioning (RIC) were previously reported by Al Malki et al (JCO 2025) demonstrating a 1-year OS of 78.6% (95% CI, 67% to 86.5%). Here, we report results from a planned expansion of the study that included 123 additional RIC recipients, with updated results from the initial cohort of 70 patients (total N = 193 subjects) treated at 33 centers. Study participants received cyclophosphamide 50 mg/kg (ideal body weight) administered on days 3 and 4 post HCT with tacrolimus and mycophenolate mofetil as previously described (Al Malki, JCO, 2025). The median study participant age was 65.0 (range: 22.9-78.9); 92 (47.7%) of participants were male, and 84 (43.5%) identified as having other than non-Hispanic white ancestry. The HCT comorbidity index was high-risk (>3) in 65 (33.7%). Underlying histologic diagnosis was AML in 96 (49.7%) participants, MDS in 43 (22.3%), ALL in 20 (10.4%), lymphoma or CLL in 24 (12.4%), and CML/other leukemias in 10 (5.2%). Conditioning regimens used were fludarabine and melphalan (100 or 140 mg/m2) (N=120; 62.2%), 2-day busulfan and fludarabine (N=38; 19.7%), and fludarabine, cyclophosphamide and total body irradiation (200 cGy) (N=32; 16.6%). Donor HLA matching (considering HLA-A, -B, -C, and -DRB1) was 7/8 in 131 (67.9%) of participants, 6/8-matched in 51 (26.4%), and 4-5/8-matched in 11 (5.7%) participants. Median donor age was 25.5 years (range: 18.7-35.7). The one-year overall OS estimate was 79.6% (95% confidence interval [CI]: 73.2-84.7). Survival was similar among HLA 7/8-matched donor recipients (77.8%, 69.7-84%) and <7/8 matched donor recipients (83.7%, 71.8-90.9%). The one-year GVHD-free, relapse-free survival (GRFS) was 49.9% (42.6-56.9%) and the one-year progression-free survival was 70.2% (63.2-76.2%). The one-year cumulative incidence (CI) rates of NRM and relapse were 12.5% (8.3-17.6%) and 17.3%(12.3-23%), respectively. The 6-month CI of grade II-IV and grade III-IV acute GVHD were 40.0% (33.0-46.8%) and 7.8% (4.6-12.1%), respectively. The one-year incidence of all chronic GVHD and severe chronic GVHD were 15.6% (10.7-21.2%) and 3.7% (1.6-7%), respectively, by NIH consensus criteria. The CI of grade 1-4 cytokine release syndrome (CRS) by day 7 post HCT was 28.0% (21.8-34.9%), and grade 3-4 CRS was 0.5% (0-2.9%). Primary engraftment failure occurred in 9 (4.7%) participants. Among 145 evaluated participants, 85.5% were >95% donor in blood chimerism at day 100 post HCT. Within the first 100 days after HCT, CTCAE grade 2-5 infections occurred in 113 (58.5%) of participants and grade 3-5 infections occurred in 59 (30.6%) of participants. The most common etiologies of grade 2-5 infections were bacterial (N=78), followed by viral (N=48). The most common grade 3-5 non-infectious toxicities were cardiac disorders, which occurred in 4 (2.1%) of participants. In conclusion, the results including this expansion cohort demonstrate encouraging 1-year OS, NRM and relapse rates in RIC recipients of PTCy-based GVHD prophylaxis and PBSC allografts from MMUDs. This larger cohort of 193 recipients re-affirm the results from the initial cohort with greater robustness.Measures to mitigate infection risk are likely to further improve outcomes. Reducing the dose of PTCy is a candidate approach currently being tested in the ongoing OPTIMIZE trial (NCT 06001385).These results support the extension of PBSC MMUD using PTCy to individuals who lack an HLA-matched donor and require RIC HCT.
Outpatient (OP) use of lisocabtagene maraleucel (liso-cel) in patients (Pts) with relapsed or refractory (R/R) large B-cell lymphoma (LBCL): Real-world data from the CIBMTR registry
Lunning, Matthew A. , Rao, Uttam K. , Lin, Yi , Crombie, Jennifer L. , Isufi, Iris, Bernasconi, David, Roy, Debasmita, Pasquini, Marcelo C. , Hunter, Bradley D. , Patel, Krish , Sdrimas, Konstantinos , Battiwalla, Minoo , Ibrahimi, Sami , Ahmed, Sairah , Frigault, Matthew J.

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 5482-5482

10.1182/blood-2025-5482 Get It

Abstract Introduction: Liso-cel, an autologous, CD19-directed CAR T cell product, has demonstrated consistent efficacy in a broad population of pts with B-cell malignancies, including R/R LBCL. Its well-established safety profile has made OP delivery commonplace. This, combined with recent changes to postinfusion monitoring requirements, offers pts the potential for greater access to care. Here, we describe real-world safety and effectiveness outcomes for pts with R/R LBCL who received liso-cel as standard of care (SOC) therapy in the inpatient (IP) or OP setting. Methods: This was an observational study of pts in the US with R/R LBCL who received commercial liso-cel as second-line (2L) or later treatment (tx) in the IP or OP setting between 02/2021 and 02/2025 and had ≥1 postinfusion assessment reported in the Center for International Blood & Marrow Transplant Research (CIBMTR). Safety outcomes included rates of AEs of special interest and nonrelapse mortality (NRM). Postinfusion hospitalizations in the OP group were also assessed. Effectiveness outcomes included ORR, CR rate, duration of response (DOR), PFS, and OS. All results are reported descriptively. Results: Of 1116 eligible pts, 34% (n=375) were intended for OP tx, as reported to the CIBMTR, including 82 of 195 (42%) pts who received liso-cel as 2L tx. Among pts treated in the IP vs OP setting, median (range) age was 71.5 y (21.5–91.2) and 69.8 y (25.0–86.1), respectively, and most pts were male (59% and 61%). Proportions of pts with high-grade B-cell lymphoma (16% and 12%), ≥2 extranodal involvement sites (26% and 26%), and secondary CNS involvement (5% and 4%) were similar for the IP and OP groups, respectively. In contrast, 48% vs 37% of pts in the IP vs OP groups, respectively, had elevated LDH before infusion and 10% vs 3% had ECOG PS ≥2. One or more comorbidities were reported for 72% and 65% (including cardiac, 36% and 32%; pulmonary, 30% and 26%; active infections requiring ongoing tx, 6% and 3%) of pts in the IP and OP groups, respectively. Median (range) number of prior lines of therapy was 3 (1–13) in the IP group and 3 (1–16) in the OP group. Use of bridging therapy was reported in 65% of the IP group and 62% of the OP group. Median (95% CI) follow-up for this study was 12.7 mo (12.5–13) in the IP group and 12.6 mo (12.4–12.8) in the OP group. Safety was similar in both settings; any-grade CRS was reported in 52% of IP vs 49% of OP setting pts, with low rates of grade 2 CRS (15% vs 11%) and grade ≥3 CRS (3% vs 2%) in both groups. Any-grade immune effector cell–associated neurotoxicity syndrome (ICANS) rates were also similar in pts in the IP vs OP setting (28% vs 23%), with low rates of grade 2 ICANS (5% vs 4%) and grade ≥3 ICANS (10% vs 8%). Prolonged cytopenia (grade 4 thrombocytopenia and/or neutropenia at 30 d after infusion) was reported in 12% and 14% in the IP and OP groups; clinically significant infections at any time after infusion occurred in 48% of IP and 42% of OP setting pts. In the IP and OP groups, 37% and 30% of pts died, most commonly due to PD (25% and 21%) and the NRM rates at 12 mo were 7.1 (95% CI, 5.2–9.4) and 4.1 (95% CI, 2.2–6.8). Among OP setting pts, 46% were not hospitalized after infusion; of those hospitalized after OP infusion, median (IQR) time to hospitalization was 5 d (3-8) and duration of stay was 5 d (3-9). Response rates were high in both the IP (ORR, 80% [95% CI, 77–83]; CR rate, 70% [95% CI, 66–73]) and OP setting (ORR, 83% [95% CI, 79–87]; CR rate, 74% [95% CI, 69–79]). At ~12 mo follow-up, median (95% CI) DOR was not reached (NR; NR–NR) in either group with 12-mo DOR rates of 59% (95% CI, 54–63) and 63% (95% CI, 56–69), respectively. Median (95% CI) PFS was 11.8 mo (8.8–NR) in the IP group vs NR (NR–NR) in the OP group, with 12-mo PFS rates of 49% (95% CI, 45–53) and 56% (95% CI, 50–61), respectively. Median (95% CI) OS was NR (NR–NR) in both groups with 12-mo OS rates of 65% (95% CI, 61–68) in the IP group and 74% (95% CI, 68–78) in the OP group. Conclusions: These results continue to demonstrate that one-time tx with liso-cel results in deep, clinically meaningful efficacy in the SOC setting across a broad population of pts with R/R LBCL. Despite the few differences reported in baseline characteristics, outcomes were consistent among pts treated in the IP and OP care settings. The well-established safety profile of liso-cel is conducive to OP tx, allowing ~50% of pts to remain out of the hospital postinfusion.
Mismatching of unrelated donors beyond a single HLA-locus does not adversely impact outcomes at one year following transplantation: Results from the NMDP sponsored ACCESS study
Bo‐Subait, Stephanie, Logan, Brent R. , Smith, Sarah , Leckrone, Erin , Stefanski, Heather, Malmberg, Craig, Modi, Dipenkumar , Meade, Javier Bolaños, Rao, Uttam K. , Milner, Jordan , Jamieson, Katarzyna , Carrum, George, Kosuri, Satyajit, Cook, Rachel J. , Ballen, Karen K. , Loren, Alison W. , Arai, Sally , Choi, Sung Won , Shaw, Bronwen E. , Larkin, Karilyn , Malki, Monzr M. Al , Auletta, Jeffery J. , Spellman, Stephen R. , Askar, Medhat , Cusatis, Rachel , Shaffer, Brian C. , Khimani, Farhad , Gooptu, Mahasweta , Hamadani, Mehdi , Maiers, Martin , Stanek, Joseph , Abboud, Ramzi , Dholaria, Bhagirathbhai , Hogan, William J. , Reshef, Ran , Qayed, Muna , Broglie, Larisa , Devine, Steven M. , Jiménez, Antonio

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 936-936

10.1182/blood-2025-936 Get It

Abstract Allogeneic hematopoietic cell transplantation (HCT) remains inaccessible to many patients, particularly those of non-European ancestry, due to the limited availability of matched unrelated donors (URD). While single-HLA mismatched donors (7/8) often yield acceptable outcomes, URD HCT mismatched at ≥ 2 HLA alleles (<7/8) has historically been associated with poor survival and prohibitive toxicity. Post-transplant cyclophosphamide (PTCy) has improved outcomes following mismatched unrelated donor (MMUD) HCT, potentially enabling less stringent donor matching. Whether the degree of donor-recipient HLA disparity remains prognostic after MMUD HCT when PTCy is used is unknown. The ACCESS trial (NCT04904588) was conducted by the Center for International Blood and Marrow Transplant Research Clinical Research Organization and prospectively evaluated PTCy-based graft versus host disease (GVHD) prophylaxis in adult recipients of 4–7/8 (HLA-A, -B, -C and -DRB1) MMUD peripheral blood stem cells (PBSC) from donors age ≤35 years old following either myeloablative (MAC) or reduced intensity/non-myeloablative (RIC/NMA) conditioning. This analysis focused on all adult recipients of <7/8 grafts enrolled on the study across both conditioning strata, with descriptive comparison to patients who received 7/8 MMUD PBSC grafts. The primary endpoint was 1-year overall survival (OS). Secondary endpoints included primary graft failure (PGF), non-relapse mortality (NRM), relapse, acute and chronic GVHD, and GVHD-free relapse-free survival (GRFS). A total of 268 adults received MMUD PBSC grafts: 85 with <7/8 matches (MAC: n=23; RIC/NMA: n=62) and 183 with 7/8 matches (MAC: n=52; RIC/NMA: n=131). Among <7/8 recipients, median age was 57 years old (range, 24–78), 49% were male, with diagnoses of acute myeloid leukemia (AML) (55%), myelodysplastic syndromes (MDS) (15%), and lymphoma (14%). HLA mismatch distribution in the <7/8 group was 6/8 in 82%, 5/8 in 14%, and 4/8 in 4%. Most received fludarabine/melphalan (44%) or myeloablative busulfan/fludarabine (21%). Median CD34+ cell dose was 5.5 ×10^6/recipient kg (range: 3.2-8.0) and 75% of grafts were cryopreserved prior to infusion. Median donor age was 25.8 (range: 18.7-35.7) in the 7/8 group and 25.0 (range: 18.3-34.8) in the <7/8 group. The <7/8 cohort was racially and ethnically diverse, with 61% identifying as other than non-Hispanic white. The 7/8 cohort had a median age of 63 years old (range, 20–79), with 52% male. Disease distribution, conditioning intensity, and infused cell doses were similar to the <7/8 group. A smaller proportion of grafts were cryopreserved (61%), and 47% of patients identified as other than non-Hispanic White. One-year OS for <7/8 recipients was 86% (95% CI: 76–92%), compared to 79% (95% CI: 72–84%) in 7/8 recipients. One-year incidence of relapse was 23% (95% CI: 14–33%) in the <7/8 group and 17% (95% CI: 12–23%) in 7/8 recipients; NRM was 8% (95% CI: 4–16%) and 14% (95% CI: 9–19%), respectively. GRFS was 55% (95% CI: 43–65%) for <7/8 and 51% (95% CI: 44–58%) for 7/8 recipients. PGF occurred in 8% (95% CI: 3–18%) of <7/8 RIC recipients and 3% (95% CI: 1–8%) of 7/8 RIC recipients; no MAC recipients had PGF. At 6 months post-HCT, grade II–IV acute GVHD occurred in 34% (95% CI: 24–44%) of <7/8 patients and 39% (95% CI: 32–46%) of 7/8; grade III–IV acute GVHD was observed in 7% (95% CI: 3–14%) and 8% (95% CI: 5–13%), respectively. Moderate to severe chronic GVHD (NIH consensus criteria) at one year occurred in 8% (95% CI: 3–15%) of <7/8 recipients and 11% (95% CI: 7–16%) of 7/8 recipients. When grouped by conditioning intensity, 1-year outcomes within the <7/8 cohort were: OS 91% after MAC and 84% after RIC/NMA; relapse in 32% after MAC and 20% after RIC/NMA, respectively; GRFS was 53% for MAC and 55% for RIC/NMA; and NRM remained low at 9% after MAC and 8% after RIC/NMA. In this cohort of adult recipients of <7/8 MMUD PBSC grafts with PTCy-based GVHD prophylaxis enrolled on the ACCESS study, 1-year OS exceeded 80% and was comparable to 7/8 recipients. Relapse, NRM, and GVHD rates were similarly favorable and consistent with outcomes reported in 7/8 donor recipients. These findings support extending suitable MMUD match considerations to include 4-6/8 in the context of PTCy, potentially enabling near-universal donor access, while allowing for optimization of other non-HLA donor factors.
Autologous stem cell transplantation after anti-PD-1 therapy for multiply relapsed or refractory Hodgkin lymphoma
Redd, Robert , Nishihori, Taiga , Nieto, Yago , Darrah, Justin , Rao, Uttam K. , Byrne, Michael , Bond, David A. , Maddocks, Kami J. , Spinner, Michael A. , Advani, Ranjana H. , Ballard, Hatcher J. , Svoboda, Jakub , Singh, Anurag K. , Modi, Dipenkumar , Ramchandren, Radhakrishnan , Cohen, Jonathon B. , Frigault, Matthew J. , Chen, Yi‐Bin , Serritella, Anthony V. , Kline, J., Ansell, Stephen M. , Nathan, Sunita , Rahimian, Maryam, Shah, Mansi , David, Kevin A. , Park, Steven , Beaven, Anne , Habib, Alma , Bachanová, Veronika , Nakhoda, Shazia , Lynch, Ryan C. , Smith, Stephen D. , Ho, Vincent T. , LaCasce, Ann S. , Armand, Philippe , Herrera, Alex F. , Redd, Robert , Bachanova, Veronika , Nishihori, Taiga , Nieto, Yago , Advani, Ranjana H , Park, Steven I , Bond, David A , Merryman, Reid W. , Chavez, Julio C , McGuirk, Joseph P. , Romancik, Jason T. , Joyce, Robin , Khan, Nadia

Blood Advances | March 12, 2021 | Volume: 5 | Issue: 6 | Pages: 1648-1659

10.1182/bloodadvances.2020003556 Get It

Abstract Autologous stem cell transplantation (ASCT) can be curative for patients with relapsed/refractory Hodgkin lymphoma (HL). Based on studies suggesting that anti-PD-1 monoclonal antibodies (mAbs) can sensitize patients to subsequent chemotherapy, we hypothesized that anti-PD-1 therapy before ASCT would result in acceptable outcomes among high-risk patients who progressed on or responded insufficiently to ≥1 salvage regimen, including chemorefractory patients who are traditionally considered poor ASCT candidates. We retrospectively identified 78 HL patients who underwent ASCT after receiving an anti-PD-1 mAb (alone or in combination) as third-line or later therapy across 22 centers. Chemorefractory disease was common, including 42 patients (54%) refractory to ≥2 consecutive systemic therapies immediately before anti-PD-1 treatment. Fifty-eight (74%) patients underwent ASCT after anti-PD-1 treatment, while 20 patients (26%) received additional therapy after PD-1 blockade and before ASCT. Patients received a median of 4 systemic therapies (range, 3-7) before ASCT, and 31 patients (41%) had a positive pre-ASCT positron emission tomography (PET) result. After a median post-ASCT follow-up of 19.6 months, the 18-month progression-free survival (PFS) and overall survival were 81% (95% CI, 69-89) and 96% (95% confidence interval [CI], 87-99), respectively. Favorable outcomes were observed for patients who were refractory to 2 consecutive therapies immediately before PD-1 blockade (18-month PFS, 78%), had a positive pre-ASCT PET (18-month PFS, 75%), or received ≥4 systemic therapies before ASCT (18-month PFS, 73%), while PD-1 nonresponders had inferior outcomes (18-month PFS, 51%). In this high-risk cohort, ASCT after anti-PD-1 therapy was associated with excellent outcomes, even among heavily pretreated, previously chemorefractory patients.
Safety and Efficacy of Allogeneic Hematopoietic Stem Cell Transplant after Programmed Cell Death 1 (PD-1) / Programmed Cell Death Ligand 1 (PD-L1) Blockade for Classical Hodgkin Lymphoma: Analysis of a Large International Cohort
Ho, Vincent T. , Arai, Sally , Lowsky, Robert , Herrera, Alex F. , Shouse, Geoffrey , Blaise, Didier , Colella, Jean‐Marc Schiano de , Ansell, Stephen M. , Spilleboudt, Chloé , Feldman, Tatyana , Dahncke, Lori, Singh, Anurag K. , Duléry, Rémy , Bastard, Aspasia Stamatoulas, Manson, Guillaume , Moles, Marie‐Pierre, Bouabdallah, Kamal , Chen, Yi‐Bin , Lynch, Ryan C. , Smith, Stephen D. , Rao, Uttam K. , Byrne, Michael , Cohen, Jonathon B. , Rahimian, Maryam, Bashey, Asad, Ballard, Hatcher J. , Svoboda, Jakub , Santoro, Armando , Armand, Philippe , Blaise, Didier , Santoro, Armando , Shouse, Geoffrey P , Merryman, Reid W. , Castagna, Luca , Corradini, Paolo , Bond, David A. , Jaglowski, Samantha , Spinner, Michael A. , Guidetti, Anna , Badar, Talha , Hamadani, Mehdi , Nieto, Yago , McGuirk, Joseph P. , Mohty, Mohamad , Houot, Roch , Orvain, Corentin , Frigault, Matthew J. , Romancik, Jason T. , Joyce, Robin , Giordano, Laura , Torri, Valter , Casadei, Beatrice , Sollini, Martina , Philippis, Chiara De , Magagnoli, Massimo , Zinzani, Pier Luigi , Carlo‐Stella, Carmelo

Blood | February 14, 2020 | Volume: 134 | Issue: Supplement_1 | Pages: 775-775

10.1182/blood-2019-125039 Get It

Introduction: Anti-PD-1 monoclonal antibodies (mAbs) are highly active in relapsed/refractory classical Hodgkin lymphoma (cHL), but most patients (pts) will still relapse. Given this, allogeneic stem cell transplantation (alloHSCT) remains an important option for pts after PD-1 blockade, as it offers the possibility of cure. Prior reports have suggested that alloHSCT after PD-1 mAbs may be associated with severe immune-related complications including acute graft-versus-host disease (GVHD), veno-occlusive disease (VOD) and cytokine release/febrile non-infectious syndrome (CRS). Prior studies of alloHSCT after PD-1 blockade in cHL have been limited by the small number of pts and short follow-up, preventing an accurate assessment of long-term outcomes and complications, risk factors for early toxicity, and the impact of transplant strategies such as choice of GVHD prophylaxis. We therefore assembled a large retrospective international cohort of cHL pts who underwent alloHSCT after PD-(L)1 blockade to better answer these questions, including an assessment of the impact of post-transplant cyclophosphamide (PTCy) on efficacy and toxicity. Methods: Medical records and databases were reviewed at 26 European and United States transplant centers to identify pts with cHL who underwent an alloHSCT any time after receiving a PD-1 or PD-L1 mAb. Response assessment was performed by local investigators according to Lugano 2014 criteria. Overall survival (OS), progression-free survival (PFS), cumulative incidence (CumInc) of relapse (CIR), non-relapse mortality (NRM), acute (a) and chronic (c) GVHD were estimated, as was the association between baseline variables and these outcomes. Results: Between 2014 and 2019, 150 pts were identified who underwent alloHSCT after a median of 10 (range, 1-74) doses of nivolumab (n=118), pembrolizumab (n=31), or avelumab (n=1). The median age was 31 (range 17-68) and pts had received a median of 4 (range, 2-11) lines of therapy prior to PD-(L)1 blockade. 138 pts (92%) had failed BV and 111 (74%) autologous HSCT. The best overall response to PD-(L)1 mAbs was CR for 62 pts (41%), PR for 55 (37%), SD for 17 (11%), PD for 15 (10%) and unknown for 1 (1%). Median time from last dose of PD-(L)1 mAb to alloHSCT was 80 days (range, 17-756) with 70 pts (47%) receiving intervening systemic therapy. At alloHSCT, 90 pts were in CR (60%), 45 in PR (30%), 5 in SD (3%), and 10 in PD (7%). Donors were haploidentical (n=71, 47%), matched sibling (n=29, 19%), matched unrelated (n=39, 26%), mismatched unrelated (n=7, 5%), cord blood (n=2, 1%), or unknown (n=2, 1%). Stem cell source was bone marrow (n=38, 25%), peripheral blood (n=110, 73%), or cord blood (n=2, 1%). GVHD prophylaxis included PTCy in 88 pts (59%) (69/71 (97%) with haploidentical donors; 19/79 (24%) with other donors). With a median post-alloHSCT follow-up for survivors of 23.8 months (range, 1-67), the 2y OS and PFS were 79% (95CI 71-86%) and 65% (95CI 55-73%), respectively, while the 2y CumIncs of relapse and NRM were 21% (95CI 13-29%) and 14%, (95CI, 8-22%), respectively (Fig. 1A-B). 27 pts have died, 3 due to disease and 24 to NRM, including aGVHD (n=7) and VOD (n=2). Veno-occlusive disease (VOD) occurred in 5 pts (day 100 CumInc 4%) and 29 pts (19%) developed CRS (grade 1 n=16; grade 2 n=7; grade 3 n=4; grade 4 n=2). The 6-month CumIncs of grade 2-4, grade 3-4 and grade 4 aGVHD were 39%, 16% and 8%, respectively. Hyperacute GVHD (onset ≤ 14 days after alloHSCT) occurred in 4% of pts and was fatal in 2 pts. The 2y CumInc of cGVHD was 45%. Neither receipt of > 10 doses (median) of anti-PD-(L)1 mAb nor undergoing alloHSCT ≤80 days (median) after last dose of PD-(L)1 mAb were associated with PFS or OS. However, pts with a shorter time to transplant (≤80 days) appeared to have a higher risk of severe (grade 3-4) aGVHD (6m CumInc 24% vs 9%, p=0.006). Recipients of PTCy in this cohort had lower 2y CumIncs of cGVHD (34% vs 58%, p=0.01) and relapse (12% vs 31%, p=0.02), superior 2y PFS (76% vs 54%, p=0.015), and similar rates of severe aGVHD (15% vs 18%, p=0.5), 2y NRM (12% vs 16%, p=0.5), and 2y OS (82% vs 78%, p=0.6). Conclusions: With extended follow-up of a large international cohort, our results argue that alloSCT performed after PD-(L)1 mAbs is a feasible strategy associated with an excellent PFS and a very low CIR for this disease. The use of PT-Cy appears to be associated with improved outcomes and may at present represent the optimal transplant strategy in this pt population. Figure Disclosures Corradini: kite: Honoraria; Abbvie: Honoraria; Servier: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Roche: Honoraria; Novartis: Honoraria; KiowaKirin: Honoraria; Janssen: Honoraria; Gilead: Honoraria; Daiichi Sankyo: Honoraria; Celgene: Honoraria; Amgen: Honoraria. Ho:Jazz Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Consultancy; Omeros Corporation: Membership on an entity's Board of Directors or advisory committees. Jaglowski:Kite: Consultancy, Other: advisory board, Research Funding; Novartis: Consultancy, Other: advisory board, Research Funding; Juno: Consultancy, Other: advisory board; Unum Therapeutics Inc.: Research Funding. Herrera:Adaptive Biotechnologies: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Gilead Sciences: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; AstraZeneca: Research Funding; Merck: Consultancy, Research Funding; Genentech, Inc.: Consultancy, Research Funding; Pharmacyclics: Research Funding; Immune Design: Research Funding; Kite Pharma: Consultancy, Research Funding. Blaise:Jazz Pharmaceuticals: Honoraria; Sanofi: Honoraria; Pierre Fabre medicaments: Honoraria; Molmed: Consultancy, Honoraria. Hamadani:Pharmacyclics: Consultancy; Sanofi Genzyme: Research Funding, Speakers Bureau; Merck: Research Funding; Otsuka: Research Funding; Janssen: Consultancy; Medimmune: Consultancy, Research Funding; ADC Therapeutics: Consultancy, Research Funding; Takeda: Research Funding; Celgene: Consultancy. Ansell:LAM Therapeutics: Research Funding; Affimed: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Affimed: Research Funding. Nieto:Astra-Zeneca: Research Funding; Affimed: Consultancy; Affimed: Research Funding; Novartis: Research Funding. Feldman:Celgene: Honoraria, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Travel expenses, Speakers Bureau; Pfizer: Research Funding; AbbVie: Honoraria, Other: Travel expenses, Speakers Bureau; Portola Pharma: Research Funding; Kite Pharma: Honoraria, Other: Travel expenses, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Pharmacyclics: Honoraria, Other: Travel expenses, Speakers Bureau; Kyowa Hakko Kirin: Research Funding; Eisai: Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Cell Medica: Research Funding; Roche: Research Funding; Corvus: Research Funding; Viracta: Research Funding; Trillium: Research Funding; Roche: Research Funding; Takeda: Honoraria, Speakers Bureau. McGuirk:ArticulateScience LLC: Other: Assistance with manuscript preparation; Bellicum Pharmaceuticals: Research Funding; Kite Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gamida Cell: Research Funding; Pluristem Ltd: Research Funding; Juno Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Research Funding; Novartis: Research Funding; Fresenius Biotech: Research Funding. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding. Stamatoulas Bastard:Celgene: Honoraria; Takeda: Consultancy. Houot:Bristol Myers Squibb: Honoraria; Merck Sharp Dohme: Honoraria. Manson:Bristol Myers Squibb: Honoraria. Orvain:Incyte: Honoraria; Novartis: Honoraria; Jazz Pharmaceuticals: Other: Travel & accommodations; Pfizer: Other: Travel & accommodations. Bouabdallah:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Frigault:Novartis: Consultancy; Kite/Gilead: Honoraria; Nkarta: Consultancy; Incyte: Consultancy; Juno/Celgene: Consultancy; Foundation Medicine: Consultancy; Xenetic: Consultancy. Chen:Takeda: Consultancy; Kiadis: Consultancy; Magenta: Consultancy; Abbvie: Consultancy; Incyte: Consultancy. Lynch:T.G. Therapeutics: Research Funding; Rhizen Pharmaceuticals S.A: Research Funding; Takeda Pharmaceuticals: Research Funding; Juno Therapeutics: Research Funding; Incyte Corporation: Research Funding; Johnson Graffe Keay Moniz & Wick LLP: Consultancy. Smith:AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck Sharp & Dohme Corp: Consultancy, Research Funding; Acerta Pharma BV: Research Funding; Portola Pharmaceuticals: Research Funding; Pharmacyclics: Research Funding; Bristol-Myers Squibb (spouse): Research Funding; Denovo Biopharma: Research Funding; Genentech: Research Funding; Ignyta (spouse): Research Funding; Incyte Corporation: Research Funding; Ayala (spouse): Research Funding; Seattle Genetics: Research Funding. Byrne:Karyopharm: Research Funding. Cohen:Hutchison: Research Funding; Astra Zeneca: Research Funding; Janssen Pharmaceuticals: Consultancy; Seattle Genetics, Inc.: Consultancy, Research Funding; Bristol-Meyers Squibb Company: Research Funding; Takeda Pharmaceuticals North America, Inc.: Research Funding; Gilead/Kite: Consultancy; Genentech, Inc.: Consultancy, Research Funding; UNUM: Research Funding; ASH: Research Funding; LAM Therapeutics: Research Funding; Lymphoma Research Foundation: Research Funding. Svoboda:AstraZeneca: Consultancy; Celgene: Research Funding; Incyte: Research Funding; Pharmacyclics: Consultancy, Research Funding; Kyowa: Consultancy; Merck: Research Funding; BMS: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding. Santoro:Bayer: Consultancy, Speakers Bureau; MSD: Speakers Bureau; Arqule: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Servier: Consultancy, Speakers Bureau; Takeda: Speakers Bureau; BMS: Speakers Bureau; Roche: Speakers Bureau; Abb-Vie: Speakers Bureau; Amgen: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Speakers Bureau; BMS: Consultancy; Lilly: Speakers Bureau; Sandoz: Speakers Bureau; Eisai: Consultancy, Speakers Bureau. Armand:Sigma Tau: Research Funding; Otsuka: Research Funding; Pfizer: Consultancy; ADC Therapeutics: Consultancy; Tensha: Research Funding; Affimed: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; Adaptive: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Infinity: Consultancy; Genentech: Research Funding. Zinzani:Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sandoz: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy; Eusapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics: Honoraria, Speakers Bureau. Carlo-Stella:Servier: Consultancy, Honoraria, Other: Travel, accommodations; Genenta Science srl: Consultancy; Boehringer Ingelheim: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Other: Travel, accommodations, Research Funding; Novartis: Consultancy, Research Funding; ADC Therapeutics: Consultancy, Other: Travel, accommodations, Research Funding; Sanofi: Consultancy, Research Funding; Rhizen Pharmaceuticals: Research Funding; Celgene: Research Funding; Amgen: Honoraria; AstraZeneca: Honoraria; Janssen Oncology: Honoraria; MSD: Honoraria; BMS: Honoraria; Janssen: Other: Travel, accommodations; Takeda: Other: Travel, accommodations.