Despite the success of the CD19 × CD3 T-cell engager blinatumomab in B-cell acute lymphoblastic leukemia (B-ALL), treatment failure is common and can manifest with antigen loss and extramedullary disease (EMD) relapse. To understand the impact of leukemia genetics on outcomes, we reviewed 267 adult patients with B-ALL treated with blinatumomab and used next-generation sequencing to identify molecular alterations. Patients received blinatumomab for relapsed/refractory (R/R) disease (n = 150) and minimal residual disease (MRD; n = 88), upfront as induction (n = 10) or as consolidation in MRD-negative state (n = 19). In the overall cohort, 50 patients (19%) had Philadelphia chromosome (Ph)–positive ALL, 80 (30%) had Ph-like ALL, 35 (13%) had TP53 mutations (TP53m), 7 (3%) had KMT2A rearrangement, and 8 (3%) had PAX5 alterations. For patients treated for R/R ALL, the overall complete remission (CR)/CR with incomplete hematological recovery (CRi) rate was 59%. Only pretreatment high disease burden (P < .01) and active EMD (P < .01) were associated with inferior CR/CRi rate. Of 169 patients in CR/CRi after blinatumomab, 79 (47%) patients relapsed, including 22 (28%) with CD19– and 54 (68%) with CD19+ relapse. In multivariable analysis, TP53m was associated with an increased risk of CD19– relapse (hazard ratio [HR], 6.84; 95% confidence interval [CI], 2.68-17.45; P < .01). Post-blinatumomab allogeneic stem cell transplantation consolidation was associated with a lower risk of CD19– relapse (HR, 0.10; 95% CI, 0.03-0.37; P < .01) and EMD relapse (HR, 0.36; 95% CI, 0.18-0.73; P < .01). In conclusion, leukemia genetics may predict patterns of blinatumomab failure, with TP53m associated with CD19– relapse.

Philadelphia (Ph)‐like acute lymphoblastic leukemia (ALL) is associated with a poor response to standard chemotherapy. However, outcomes with novel antibody and cellular therapies in relapsed/refractory (r/r) Ph‐like ALL are largely unknown. We conducted a single‐center retrospective analysis of adult patients (n = 96) with r/r B‐ALL and fusions associated with Ph‐like who received novel salvage therapies. Patients were treated with 149 individual novel regimens (blinatumomab = 83, inotuzumab ozogamicin [InO] = 36, and CD19CAR T cells = 30). The median age at first novel salvage therapy was 36 years (range; 18–71). Ph‐like fusions were IGH::CRLF2 (n = 48), P2RY8::CRLF2 (n = 26), JAK2 (n = 9), ABL‐class (n = 8), EPOR::IGH (n = 4) and ETV6::NTRK2 (n = 1). CD19CAR T cells were administered later in the course of therapy compared to blinatumomab and InO (p < .001) and more frequently in recipients who relapsed after allogeneic hematopoietic cell transplantation (alloHCT) (p = .002). Blinatumomab was administered at an older age compared to InO and CAR T‐cells (p = .004). The complete remission (CR)/CR with incomplete hematologic recovery (CRi) rates were 63%, 72%, and 90% following blinatumomab, InO and CD19CAR, respectively, among which 50%, 50%, and 44% of responders underwent consolidation with alloHCT, respectively. In multivariable analysis, the type of novel therapy (p = .044) and pretreatment marrow blasts (p = .006) predicted the CR/CRi rate, while the Ph‐like fusion subtype (p = .016), pretreatment marrow blasts (p = .022) and post‐response consolidation with alloHCT (p < .001) influenced event‐free survival. In conclusion, novel therapies are effective in inducing high remission rates in patients with r/r Ph‐like ALL and successfully transitioning the responders to alloHCT.

CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy has led to unprecedented rates of complete remission (CR) in children and adults with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL), yet the majority of adults relapse after initial response. One proposed method to extend the durability of remission in adults following response to CAR-T therapy is consolidation with allogeneic hematopoietic cell transplantation (alloHCT). Considering the limited published data for the utility of post CAR-T therapy consolidative alloHCT in r/r B-ALL, especially data related to patients receiving a second alloHCT, we sought to describe outcomes of patients with r/r B-ALL at our institution who received their first or second alloHCT following response to CAR-T therapy. We performed a retrospective analysis of adult patients with r/r B-ALL who responded to either investigational or standard of care (SOC) CD19-targeted CAR-T therapy and underwent consolidation with alloHCT while in CR without interim therapy. We identified 45 patients, of whom 26 (58%) and 19 (42%) received their first and second alloHCT as consolidation post CAR-T therapy, respectively. The median age was 31 years (range: 19-67) and 31 (69%) patients were Hispanic. Ph-like was the most common genetic subtype and comprised over half of cases (53%; n=24). The median number of prior therapies pre-transplant was 5 (range: 2-7), and disease status at the time of alloHCT was CR1, CR2 or ≥CR3 in 7 (16%), 22 (49%) and 16 (35%) patients, respectively. The median time from CAR-T therapy until alloHCT was 93 (range: 42-262) days. The conditioning regimen was radiation-based myeloablative (MAC) in 22 (49%) patients. With a median follow-up of 2.47 years (range: 0.13-6.93), 2-year overall survival (OS), relapse free survival (RFS), cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) were 57.3% (95%CI: 0.432-0.760), 56.2% (95%CI: 0.562-0.745), 23.3% (95% CI:0.13-0.42), and 20.4% (95%CI: 0.109-0.384), respectively. Two-year OS (52% vs. 68%, p=0.641), RFS (54% vs. 59%, p=0.820), CIR (33.5%% vs. 8.5%, p=0.104), and NRM (12.5% vs. 32.2%, p=0.120) were not significantly different between patients who underwent their first vs. second transplant, respectively. In univariate analysis, only Ph-like genotype was associated with inferior RFS (p=0.03). AlloHCT post CAR-T response is associated with a relatively low early mortality rate and encouraging survival results in high-risk adults with r/r B-ALL, extending to the second alloHCT for fit and eligible patients.

Sinusoidal obstruction syndrome (SOS) is a potentially life-threatening complication that can be observed after allogeneic hematopoietic cell transplantation (HCT). Inotuzumab ozogamicin is an anti-CD22 monoclonal antibody-drug conjugate that has demonstrated high efficacy in relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) but is associated with an increased risk of SOS in HCT recipients. Here we aimed to examine the incidence and outcomes of SOS in 47 adult patients with R/R ALL who received inotuzumab therapy and subsequently underwent HCT at our institution. All patients received prophylactic therapy with ursodiol, and continuous low-dose heparin also was administered to patients receiving myeloablative conditioning (MAC). SOS occurred in 12 patients (26%) post-HCT, at a median onset of 11 days (range, 3 to 41 days). SOS was graded as very severe in 50% (n = 6), severe in 25% (n = 3), and mild in 25% (n = 3). All patients diagnosed with SOS received treatment with defibrotide for a median of 21 days (range, 3 to 34 days), with resolution of SOS occurring in 8 patients (67%). Mortality from SOS was 33% (n = 4) and occurred at a median of 10 days from diagnosis (range, 3 to 31 days) in patients graded as very severe (n = 3) or severe (n = 1). There were no significant differences between patients who developed SOS and those who did not develop SOS in the median time from the last dose of inotuzumab to transplantation (46 days versus 53 days; P = .37), use of an MAC regimen (42% versus 49%; P = .75), number of lines of therapy prior to inotuzumab (P = .79), median number of administered cycles of inotuzumab (2 versus 2; P = .14), or receipt of inotuzumab as the last therapy prior to HCT (67% versus 66%; P = 1.0). Sirolimus-based graft-versus-host disease (GVHD) prophylaxis was used more frequently in the SOS group (75% versus 29%; P < .01), but there was no between-group difference in the peak sirolimus level (P = .81) or the median time to peak sirolimus level (7 days versus 3.5 days; P = .39). In univariable analysis, only the use of sirolimus-based GVHD prophylaxis was significantly associated with an increased risk of SOS (hazard ratio [HR], 7.50; 95% confidence interval [CI], 1.7 to 33.6; P < .01). In the SOS group, the 100-day mortality rate was 33% (n = 4), and median overall survival (OS) post-HCT was 4.3 months (range, 0.2 to 57.2 months). In the group without SOS, the 100-day mortality rate was 14% (n = 5) and the median OS post-HCT was 10.7 months (range, .52 to 39.6 months). In this study cohort, SOS was prevalent in HCT recipients who had been treated with inotuzumab prior to transplantation, and sirolimus-based GVHD prophylaxis was a risk factor for SOS in inotuzumab recipients.

Rearrangements of lysine [K] methyltransferase 2 A (KMT2A) gene, previously known as the MLL gene, occur in 3 to 7% of adult patients with de novo AML and are enriched in therapy-related disease, p...

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has emerged as a global pandemic that upended existing protocols and practices, including those for allogeneic hematopoietic stem cell transplantation (HCT). Here, we describe the successful clinical course and multiple key interventions administered to an acute lymphoblastic leukemia patient, who tested SARS-CoV-2 positive by reverse transcriptase polymerase chain reaction on day −1 of matched unrelated donor (SARS-CoV-2 immunoglobulin G negative) T-cell-replete HCT. This experience allowed for implementing a virologic and immunomonitoring panel to characterize the impact of SARS-CoV-2 on the recipient’s nascent humoral and cellular immune response. The finding of robust, functional, and persistent levels of SARS-CoV-2-specific T cells, starting early after transplant was unexpected, and in combination with the clinical strategy, may have contributed to the favorable outcome. Additionally, it is plausible that preexisting cross-reactive endemic coronavirus immunity in the allogeneic graft reduced recipient susceptibility to COVID-19 disease. This case supports the critical role that T-cell responses may play in mitigating SARS-CoV-2 infection, even in the context of transplant immunosuppression, in which reconstitution of humoral response is commonly delayed. Interventional approaches to transfer SARS-CoV-2-specific cellular immunity such as HCT donor vaccination and adaptive cellular therapy could be of benefit.