Background Conventional allogeneic hematopoietic stem cell transplantation (alloHSCT) is associated with increased toxicity and infections due to multiagent immunosuppression. Orca-T, a high-precision engineered allogeneic T cell immunotherapy utilizing single-agent GVHD prophylaxis, demonstrated superior survival free of chronic GVHD (HR = 0.26; p < 0.00001), significantly lower moderate to severe chronic GVHD (12.6% vs 44.0%; p < 0.001), and fewer serious infections and deaths at 1 year versus alloHSCT in a phase 3 trial. This study compares health-related quality of life (HRQoL) and hospitalization patterns between arms. Methods Adults aged 18–65 undergoing myeloablative alloHSCT for acute leukemia in remission or high-risk MDS (≤10% BM blasts) with matched related or unrelated donors were randomized 1:1 to Orca-T + tacrolimus or unmanipulated PBSC + Tac/MTX. Exploratory outcomes included HRQoL and hospitalization. HRQoL was measured using the FACT-BMT instrument (0–164 scale; higher scores indicate better HRQoL) at baseline and predefined intervals. A repeated measures model assessed change over time. Duration of initial hospitalization, rehospitalization rates, total hospitalized days, and rehospitalization-free survival were compared between arms. Results Safety analyses included 88 Orca-T and 94 Tac/MTX patients, with grade 3–4 acute GVHD rates of 5.7% vs 9.6% and moderate–severe chronic GVHD of 12.5% vs 34.0%. Survey completion was >85% at baseline and ∼66% at 1 year. FACT-BMT scores were consistently higher for Orca-T, with smaller declines at day 14 (−7.74 vs −13.69) and recovery above baseline by day 100 (1.34 vs −3.12), sustained through day 365. Subscale scores exceeded baseline earlier and were ≥2-fold higher by day 365. Median hospitalization was 24.5 vs 24.0 days; rehospitalizations 27.3% vs 45.7%; total hospitalized days 30.6 vs 40.8; ICU admissions 1 vs 4. Rehospitalization-free survival at 18 months was 66.4% (95% CI 54.0–76.2) vs 33.8% (95% CI 18.5–49.9) (p = 0.0096; HR 0.53 [0.32–0.86]). Conclusions Orca-T recipients experienced higher HRQoL, faster recovery, fewer ICU stays, lower rehospitalization rates, and improved rehospitalization-free survival compared to Tac/MTX, suggesting improved early post-transplant recovery and reduced GVHD symptom burden.

Background Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only potentially curative intervention for myelodysplastic syndrome (MDS), but novel strategies are needed to reduce relapse and improve survival. Orca-T is an investigational precision cell therapy for treatment of hematological malignancies. In a Phase 1b clinical trial (NCT04013685), Orca-T exhibited an excellent safety profile and low rates of severe Graft-versus-Host disease (GVHD). In a Phase 3 prospectively randomized trial (NCT05316701), Orca-T met the primary endpoint of improving moderate-to-severe chronic GVHD-free survival in comparison to calcineurin inhibitor/methotrexate prophylaxis. The goal of the present study was to compare the clinical outcomes of myelodysplastic syndrome (MDS) patients who received either Orca-T or post-transplant cyclophosphamide (PTCy) for the control of GVHD. Methods The Orca-T patients in this study included all MDS patients in the Ph3 trial who received Orca-T and all MDS patients in the Ph1b trial who met the Ph3 eligibility criteria. For comparison to PTCy patients, a dataset was acquired from CIBMTR-NMDP. The PTCy patients in this study included those in the CIBMTR registry who had a diagnosis of MDS, received PTCy + tacrolimus ± mycophenolate, and had pre-transplant demographic and clinical profiles that were similar to the Orca-T patients. Additional inclusion criteria were ages 18-65, myeloablative conditioning regimen, and an 8/8 HLA-matched donor. We studied the following endpoints: overall survival (OS), relapse-free survival (RFS), GVHD and relapse-free survival (GRFS), moderate-severe chronic GVHD-free survival (cGFS), and the cumulative incidences of non-relapse mortality (NRM), relapse, grades 3-4 acute GVHD and moderate-severe chronic GVHD. Standard survival and competing risk methods were used; p<.05 defined significance. Results Orca-T MDS patients (n=25), in comparison to PTCy MDS patients (n=95), exhibited increased OS (p=.003), increased RFS (p=.005), and decreased relapse (p=.026) (Table 1 and Fig. 1). The 1-year estimates for NRM, GRFS and gr. 3-4 aGVHD favored Orca-T, but did not reach statistical significance. The cumulative incidence of moderate-to-severe cGVHD was lower in the PTCy group, but cGFS was similar. The analysis consistently showed lower overall survival estimates for PTCy patients across various subgroups, defined by recipient age, sex, HCT-CI, KPS, and donor type. Thus, differences in demographic and clinical characteristics between the treatment groups are unlikely to explain the overall observed difference in OS. Conclusions In conclusion, MDS patients treated with Orca-T, in comparison to PTCy, exhibited increased OS, increased RFS, decreased relapse, and decreased NRM. These observations provide evidence supporting the use of Orca-T for improved clinical outcomes.

Background Orca-T is an investigational precision cell therapy for allogeneic treatment of hematological disorders. In a Phase 1b clinical trial (NCT04013685) with patients having acute leukemias or MDS, Orca-T exhibited an excellent safety profile and low rates of severe Graft-versus-Host Disease (GVHD). In a Phase 3 randomized trial (NCT05316701), in comparison to calcineurin inhibitor/methotrexate prophylaxis, Orca-T met the primary endpoint of improving moderate-to-severe chronic GVHD-free survival (cGFS). Here we retrospectively compared the clinical outcomes of Orca-T patients to those receiving post-transplant cyclophosphamide (PTCy) for GVHD prophylaxis. Methods The Orca-T patients in this study (n=164) included all participants in the Ph3 trial who received Orca-T (n=88), as well as participants in the ph1b trial who met the Ph3 eligibility criteria (n=76). The PTCy patients (n=380) included those in the CIBMTR registry who received PTCy + tacrolimus ± mmf and had pre-transplant demographic and clinical profiles that were similar to the Orca-T patients. Additional inclusion criteria were ages 18-65, intermediate- to high-risk AML or ALL in CR or MDS, rmyeloablative conditioning, and an 8/8 HLA-matched donor. The endpoints compared were overall survival (OS), relapse-free survival (RFS), cGFS, and the cumulative incidences of non-relapse mortality (NRM), relapse, gr. 3-4 acute GVHD, and moderate-severe chronic GVHD. Competing risks were death for the cumulative incidences of relapse and GVHD, and relapse for NRM. Time-to-event outcomes were analyzed from the transplantation date until the first event or date of last contact. Standard survival and competing risk methods were used; p<.05 defined significance. Results Orca-T patients, in comparison to the PTCy patients, exhibited increased OS (p<.001), increased RFS (p=.045), and decreased NRM (p=.033) (Table 1 and Fig. 1). GRFS, relapse, and aGVHD grades 3-4 estimates did not significantly differ between the treatment groups. The 1-year cumulative incidence of moderate-severe cGVHD was lower in the PTCy group, but the cGFS rates were not significantly different.The increased OS effect of Orca-T was consistently observed in subgroups of patients (e.g., age, HCT-CI, DRI, disease type) that can be associated with disparate clinical outcomes. Noteworthy was the increased OS (p=.034) and decreased NRM (p=.048) in patients >50 years of age. Conclusions In conclusion, Orca-T patients, in comparison to PTCy patients in the CIBMTR registry, exhibited increased OS, increased RFS, and decreased NRM. These observations were consistently observed in stratified analyses, with further separation in clinical effect between Orca-T and PTCy in patients >50 years of age.

Background Orca-T is an investigational precision cell therapy that has been evaluated in the context of myeloablative conditioning for allogeneic treatment of hematological disorders. In a ph1b clinical trial (NCT04013685) in patients with acute leukemias and MDS, Orca-T exhibited an excellent safety profile and low rates of serious graft-versus-host disease (GVHD). In a ph3 randomized trial (NCT05316701), in comparison to calcineurin inhibitor/methotrexate prophylaxis, Orca-T met the primary endpoint of improving moderate-to-severe chronic GVHD-free survival. Studies of Orca-T combined with reduced intensity conditioning (RIC) are ongoing. Here we report interim clinical outcomes in Orca-T patients who received RIC in comparison to a registry cohort who received RIC plus post-transplant cyclophosphamide (PTCy). Patients and Methods Patients on a single-center ph1 study (NCT05088356) of Orca T in RIC who were diagnosed with ALL, AML, or MDS (n=46) were included in this evaluation. The other patients with myelofibrosis or a haploidentical donor were excluded (n=7). Contemporaneous patient level data were obtained from CIBMTR-NMDP. The comparator group included adults in the CIBMTR registry treated with RIC + PTCy + tacrolimus ± mycophenolate (n=587). The pre-transplant demographic and clinical characteristics were similar between cohorts. The included participants were adults ages 60-75, had intermediate- to high-risk AML, ALL or MDS, received RIC, and had a 7/8 or 8/8 HLA-matched donor. We studied the following endpoints: overall survival (OS), relapse-free survival (RFS), GVHD and relapse-free survival (GRFS), moderate-severe chronic GVHD-free survival (cGFS), and the cumulative incidences of non-relapse mortality (NRM), relapse, grades 3-4 acute GVHD and moderate-severe chronic GVHD. Standard survival and competing risk methods were used; p<.05 defined significance. Results Although this is a retrospective analysis, each of the clinical outcome estimates strongly favored Orca-T, with RFS (p=.034), GRFS (p=.012), and cGFS (p=.034) (Table 1). Notably, the 1-year GRFS estimate for Orca-T of 75% (95% CI = 57-86%) was remarkably high (Figure 1). While the cumulative incidence estimates of serious GVHD were low in both groups, none of the Orca-T patients experienced gr. 3-4 aGVHD. Conclusions Interim analyses of RIC + Orca-T patients revealed low GVHD, relapse, and NRM rates. Comparison to RIC + PTCy patients in the CIBMTR registry suggested a clinical benefit of RIC + Orca-T. These findings provide insight for improving clinical outcomes in older patients and high comorbidity patients unable to receive myeloablative conditioning regimens.

Background Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is an option for patients without matched donors. Despite advances, outcomes remain limited by immunological barriers, leading to higher risks of graft-versus-host disease (GVHD), delayed immune recovery, and variable relapse rates. Orca-Q is a precision-engineered, immune cell therapy designed to facilitate immune recovery and maintain GVL while reducing GVHD. with less immunosuppression. This study reports interim results from an ongoing study (NCT03802695). Methods Adult patients with high-risk hematologic malignancies who were eligible for myeloablative conditioning (MAC) alloHSCT with a haploidentical donor were enrolled in a dose expansion study using single agent tacrolimus for GVHD prevention. Inclusion criteria were broad, 44 patients in total were treated, and here, we report data for 39 patients age <65 with AML, ALL, or MDS. Orca-Q was centrally manufactured at an Orca Bio GMP facility (Sacramento, CA) from GCSF-mobilized peripheral blood apheresis products. Patients were followed for GVHD and relapse for one year and for overall survival (OS) thereafter. GVHD-free, relapse-free survival (GRFS) was defined as the time from transplant to the first occurrence of grade 3-4 acute GVHD (aGVHD), moderate to severe chronic GVHD (cGVHD), relapse or death. Results Orca-Q was successfully manufactured and administered with a vein-to-vein time of less than 72 hours. 39 patients were treated, baseline characteristics were as follows: Median age 44 years (range 21-64), 77% male; median follow-up was 937 days (range 19-1825). All patients received MAC with one of the following regimens: Bu/Flu/Thio-based, TBI/Flu/Thio, TBI/Flu. Patients who received TBI/Flu/Thio were also analyzed separately.Orca-Q was well-tolerated and all patients engrafted neutrophils by day +19 (median 11 days). Two patients with busulfan-based conditioning experienced secondary graft failure. Clinical outcomes were as follows: Conclusions The study demonstrated high engraftment rates, encouraging OS and RFS, and low incidences of severe aGVHD and cGVHD. Notably, outcomes appeared favorable in the TFT subgroup, with improved survival, GRFS, and lower relapse incidence compared to other regimens. These findings support the safety and efficacy of Orca-Q in reducing GVHD and achieving durable remissions. The Phase 1 study continues to enroll patients to confirm these results.

Orca-T is a cellular immunotherapy comprising purified donor hematopoietic progenitor stem cells, regulatory T cells (Tregs), and conventional T cells (Tcons). Both Orca-T and post-transplant cyclophosphamide (PTCy) have demonstrated superior graft-versus-host disease (GVHD) control compared to tacrolimus and methotrexate in randomized clinical trials. Orca-T achieves immune tolerance through high-purity regulatory T cells in contrast to broad pharmacological immunosuppression with PTCy regimens. The principal goal of this study was to evaluate the long-term overall survival (OS) of Orca-T compared to PTCy. In this retrospective analysis, long-term survival follow-up was collected from a multicenter Phase 1b study of Orca-T that was initiated in 2019. OS outcomes were evaluated against a cohort of patients receiving PTCy-based GVHD prophylaxis, using a registry dataset obtained from the Center for International Blood and Marrow Transplant Research/NMDP. To ensure comparability, inclusion criteria were aligned with Orca-T Ph3 eligibility, specifically age ≤65 yr, diagnosis of intermediate- or high-risk acute myeloid leukemia or acute lymphoblastic leukemia in complete remission or myelodysplastic syndrome, myeloablative conditioning, and an 8/8 HLA-matched donor. The analysis included 76 Orca-T patients and 360 PTCy patients. Orca-T was associated with significantly higher OS over a 3-yr follow-up period compared to PTCy (hazard ratio [HR] = 0.41; log-rank P = .003). OS at 1, 2, and 3 yr for Orca-T was 96% (95% CI: 88% to 99%), 86% (76% to 92%), and 83% (73% to 90%), respectively. For the PTCy cohort, OS at 1, 2, and 3 yr was 81% (77% to 85%), 72% (67% to 77%), and 66% (60% to 71%), respectively. A propensity score-matched analysis (n = 76/group) confirmed the primary findings (HR = 0.40; log-rank test P = .010), as did a multivariable Cox model adjusted for recipient age, sex, disease, disease risk index, HCT-CI, and donor type (adjusted HR = 0.38; 95% CI 0.21 to 0.71; P = .002). The advantage persisted in sensitivity analyses excluding bone marrow grafts from the comparator and restricting both arms to the overlapping 2019 to 2021 transplant era (HR range across all specifications, 0.36 to 0.48). Three-yr nonrelapse mortality was lower with Orca-T (3.1% versus 10%; Gray's P = .0497), while relapse did not differ significantly; within the PTCy cohort, outcomes did not differ by mycophenolate mofetil use. The OS advantage for Orca-T was consistently observed across age, disease type, and other clinical subgroups. Within the limitations of this retrospective analysis, these results suggest that survival following allogeneic hematopoietic stem cell transplantation may be improved with Orca-T relative to PTCy.

Introduction Several prognostic biomarkers have been studied in acute graft versus host disease (aGVHD), but none are targetable. Thymic stromal lymphopoietin (TSLP) is an IL7-like cytokine produced by epithelial cells in skin and gastrointestinal tract, in response to environmental and proinflammatory stimuli. Two isoforms of TSLP are known. The 7kDa short isoform is constitutively expressed and mediates homeostatic functions while the 18kDa long isoform is upregulated in inflammation. The heterodimeric TSLP receptor contains the IL-7Ra subunit and is expressed on dendritic cells, B cells, activated and memory T cells and absent on regulatory T cells. TSLP-receptor binding leads to downstream activation of JAK-STAT, driving antigen exposed CD4+ T cells towards Th-2 differentiation and production of IL4, IL5, IL13 and TNFa. TSLP is implicated in type-2 and Th-17 type immune responses, with the latter known to play a role in GVHD. Anti-TSLP monoclonal antibody Tezepelumab is approved for steroid refractory asthma. TSLP levels when measured by ELISA do not differentiate the isoforms. We measured TSLP isoforms with nano immunoassay (NIA) in plasma and serum of allogeneic stem cell transplant (HCT) recipients with and without aGVHD. Objective To test the association of TSLP isoform levels with presence and/or severity of aGVHD. Methods TSLP levels were measured in plasma and serum samples obtained from 19 HCT patients without GVHD and 23 HCT patients with aGVHD from Stanford University, and 60 patients with steroid refractory lower gastrointestinal tract (SR-LGI) aGVHD at start of second line therapy obtained from the Mount Sinai Acute GVHD International Consortium (MAGIC) biorepository. TSLP was measured using Peggy Sue NIA as relative units of chemiluminescence. Using the Wilcoxon rank sum test, p values were generated for pairwise comparisons with Holm-Bonferroni multiple comparisons correction. Results Using NIA we discovered novel, high molecular weight isoforms (HMWI) of TSLP ranging from 29kDa to 40kDa size. Median TSLP HMWI levels were 33952 (IQR 29410, 41953) without aGVHD, doubled to 68305 (IQR 46349, 95888) with aGVHD (any organ), and quadrupled to 130152 (IQR 105578, 194797) in SR-LGI-aGVHD (Table 1). Pairwise comparisons between no GVHD vs aGVHD (p=0.0008) and aGVHD vs SR-LGI-aGVHD (p<0.0001) demonstrated significance. (Table2 & Fig1). In SR-LGI-aGVHD, there was no significant difference in TSLP HMWI levels between survivors and 6mNRM group (p=0.8). Conclusions Novel HMW isoforms of TSLP measured with NIA are significantly higher in aGVHD and increase further in SR-LGI-aGVHD, indicating that TSLP may have value as a diagnostic and predictive biomarker in aGVHD. Molecular characterization of the newly discovered TSLP isoforms, the role of TSLP in the pathogenesis of aGVHD and therapeutic targeting of TSLP in aGVHD with monoclonal antibodies warrant investigation.

To prevent graft-versus-host disease (GVHD) in patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation (alloHSCT), a calcineurin inhibitor plus methotrexate is routinely used. Early phase studies suggested improved outcomes with Orca-T, an allogeneic T-cell immunotherapy that uses purified donor Treg cells to prevent GVHD with significantly less immunosuppression. This phase 3 trial randomized adult patients (N=187) with acute leukemias or myelodysplastic syndrome undergoing myeloablative conditioning to receive either Orca-T with tacrolimus or a conventional allograft with tacrolimus and methotrexate (Tac/MTX), using granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood from HLA-matched donors. The primary endpoint was survival free from moderate-to-severe chronic GVHD (cGFS). Using a stratified log-rank test, cGFS was significantly higher in the Orca-T arm compared to Tac/MTX (P<0.001; HR 0.26; 95% CI, 0.14 to 0.47). One-year estimates were as follows: cGFS was 78.0% with Orca-T versus 38.4% with Tac/MTX; cumulative incidence of moderate-to-severe chronic GVHD (cGVHD) was 12.6% with Orca-T and 44.0% with Tac/MTX (Gray’s test P<0.001), while overall survival (OS) was 93.9% with Orca-T versus 83.1% with Tac/MTX (P=0.12); GVHD and relapse-free survival (GRFS) was 63.1% and 30.9% in the Orca-T and Tac/MTX arms (P<0.001), respectively; non-relapse mortality (NRM) was 3.4% with Orca-T versus 13.2% with Tac/MTX (P=0.03). Orca-T met the primary endpoint of improved survival free from cGVHD compared to Tac/MTX prophylaxis and should be considered a new therapeutic option with low toxicity for GVHD prophylaxis. Additionally, significantly less toxicity was observed with Orca-T patients including fewer serious infectious complications and less non-relapse mortality. (ClinicalTrials.gov number NCT05316701).

Introduction Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative therapy for patients with hematologic malignancies, but its success is limited by GVHD, which is associated with substantial morbidity, mortality, and economic burden. Orca-T, an investigational, high-precision cell therapy, demonstrated improvement in survival free of moderate-to-severe chronic GVHD compared to conventional allo-HCT with tacrolimus/methotrexate (TAC/MTX) in the pivotal Phase 3 Precision- T trial. Given the rising costs of GVHD therapies and the long-term care burden, assessing the economic value of Orca-T is essential. Objective To assess the cost effectiveness of Orca-T compared to conventional allo-HCT with TAC/MTX GVHD prophylaxis from a US health system perspective. Methods A three-state partitioned survival model (relapse-free, relapsed, and dead) with monthly cycles and a lifetime horizon was developed. The intervention arm included Orca-T with single-agent tacrolimus, while the comparator arm included conventional allo-HCT with TAC/MTX GVHD prophylaxis. Overall survival and relapse-free survival data from the Phase 3 Precision-T study were incorporated using a cure-mixture modeling approach to estimate long-term survival and relapse status for patients. Costs included conditioning regimens, index procedure length of stay, Orca-T acquisition, donor procurement (conventional allo-HCT with TAC/MTX only), acute GVHD (aGVHD) and chronic GVHD (cGVHD) management, infection management, and terminal care. Model outcomes included life-years, quality-adjusted life-years (QALYs), and direct healthcare costs. Both costs and outcomes were discounted at 3% annually. Results Orca-T was associated with lower lifetime costs of $1,412,864 compared to $2,253,413 for conventional allo-HCT with TAC/MTX with a lifetime cost savings of $840,548 per patient. The costs associated with Orca-T acquisition were offset by savings from aGVHD, infection, and cGVHD management costs. The cGVHD management costs were $735,974 for Orca-T compared to $1,984,702 for conventional allo-HCT with TAC/MTX. Orca-T was also associated with 15.80 QALYs compared to 11.45 QALYs with conventional allo-HCT with TAC/MTX over a patient's lifetime. Given the combination of cost savings and QALY gains, Orca-T is dominant over conventional allo-HCT with TAC/MTX. Conclusion Over a patient's lifetime, the model demonstrated that Orca-T can reduce the overall economic burden compared to conventional allo-HCT with TAC/MTX, with the majority of cost savings driven by reductions in aGVHD, infection, and cGVHD management costs. Given the considerable clinical and economic impact of these complications, Orca-T represents a high value therapeutic option for adults with advanced hematologic malignancies, offering both superior clinical outcomes and economic benefits.

Abstract:Mild bleeding disorders (MBDs) comprise a heterogeneous group of inherited conditions characterized by clinically relevant bleeding symptoms despite largely normal or inconclusive results in routine hemostatic testing. These disorders account for a substantial proportion of referrals to specialized hemostasis clinics and include von Willebrand disease (VWD), inherited platelet function disorders, and mild coagulation factor deficiencies. Despite systematic diagnostic algorithms, many patients with MBDs remain without a definitive diagnosis and are classified as having bleeding disorder of unknown cause (BDUC), complicating clinical management and counseling. Conventional diagnostic approaches rely on structured bleeding assessment tools, detailed family history, and stepwise laboratory testing. Biological variability, assay limitations, and phenotypic overlap often result in inconclusive findings. Abstract:Recent advances in genetic analysis have begun to transform this diagnostic landscape. Targeted next-generation sequencing panels, whole-exome sequencing (WES), and whole-genome sequencing (WGS) enable identification of pathogenic variants across numerous hemostasis-related genes. In MBDs, genetic testing is valuable for refining diagnoses in qualitative VWD, confirming inherited platelet disorders, and identifying rare mild coagulopathies. In contrast, its diagnostic yield in type 1 and low von Willebrand factor (VWF) is modest, reflecting complex genetic architecture, modifier effects, and incomplete penetrance. In BDUC, genetic testing has revealed monogenic causes in some patients and multifactorial contributions in others. Abstract:Genetic testing should therefore be regarded as a complementary tool rather than a replacing conventional diagnostics. Integrated with clinical and laboratory findings and supported by expert variant interpretation, it can reduce diagnostic uncertainty and improve disease classification in patients with MBDs.

Orca Bio is a clinical-stage biotechnology company advancing a pipeline of high-precision allogeneic cell therapies to replace diseased blood and immune systems. Our lead investigational candidate, Orca-T, is manufactured from mobilized apheresis collections of 8/8 HLA-matched donors and comprises purified regulatory T cells (Treg), hematopoietic stem and progenitor cells (HSPC), and conventional T cells (Tcon). Donor products are transported to a central GMP facility, where each cellular component is purified and formulated. Treg and HSPC are shipped as fresh infusions, while Tcon is cryopreserved. Final products are couriered under controlled conditions to treatment centers for administration. Logistics across apheresis sites, the central facility, and clinical centers are supported by OrcaPort, a proprietary supply chain platform, in partnership with the National Marrow Donor Program (NMDP).We report manufacturing and distribution data from Orca-T in the Phase 1b (NCT4013685) and Phase 3 (NCT05316701) trials. Between December 2019 and September 2024, 243 products were manufactured, 215 from single-day collections and 28 from two-day collections. Time zero was defined as completion of the final collection. Apheresis centers and treatment centers were utilized widely across the US (Figure 1). Overall, 96% of products were delivered within 60 hours and 100% within 70 hours; 99% were infused within the 72-hour release window. Product quality was consistent: adjusted ideal body weight averaged 74 ± 13 kg (46–104); Treg dose was 2.7 ± 0.4 × 10⁶/kg (1.3–3.7) with 92% ± 3% purity (78–97%); HSPC dose was 6.2 ± 3.0 × 10⁶/kg (1.1–15.2); residual T cells were 17 ± 134 × 10³/kg (0–1825); Tcon products were dosed at 3 × 10⁶/kg.These results demonstrate that Orca-T can be reliably manufactured at scale, maintaining high purity, and distributed nationwide within a controlled logistics framework. Collectively, these findings establish the feasibility of precision-engineered cell therapy manufacturing and distribution to enable multicenter clinical studies and lay the foundation for future commercial application.

Inherited platelet disorders (IPDs) are rare bleeding disorders characterized by impaired platelet function and/or reduced blood platelet count. Their diagnosis typically relies on complex laboratory methods, including flow cytometry, aggregometry, and molecular genetic analysis. In recent years, immunofluorescence microscopy has been established as an alternative diagnostic method for IPDs. Background/Objectives: This study aims to validate a quantitative approach enhancing reproducibility through automated image analysis for diagnosing IPDs using immunofluorescence microscopy, with Bernard-Soulier Syndrome (BSS) and Glanzmann thrombasthenia (GT) as model IPDs. Methods: Native blood smears from patients with suspected BSS or GT were stained using a standardized immunofluorescence protocol targeting platelet surface glycoproteins, granules, and cytoskeletal components. The slides were analyzed using an automated fluorescence microscope, and a rule-based subpopulation analysis was implemented to quantify fluorescence signals. The results were compared to those of a healthy control group, as well as data from flow cytometry and molecular genetic testing. Results: The automated analysis successfully differentiated BSS and GT patients from healthy controls based on distinct fluorescence signal patterns. In BSS samples, CD42b (GPIbα) expression was absent or severely reduced, while GT samples showed a deficiency of CD41/CD61 (GPIIb/IIIa). The platelet size distribution confirmed macrothrombocytopenia in BSS patients. Flow cytometry and molecular genetic testing corroborated these findings, supporting the diagnostic reliability of the automated immunofluorescence microscopy approach. Conclusions: This proof-of-principle study demonstrates that automated quantitative immunofluorescence microscopy is a viable alternative for diagnosing IPDs, offering a standardized, objective, and efficient method, particularly in settings where flow cytometry is not feasible.

BACKGROUND Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains the only potentially curative option for several high-risk blood cancers and benign blood disorders. Conventional stem cell sources include high doses of T cells that contribute to graft-versus-leukemia (GVL) and graft-versus-infection (GVI) effects, but they also mediate graft-versus-host disease (GVHD). Preventing GVHD following alloHSCT typically requires multi-agent immunosuppression, commonly involving methotrexate or post-transplant cyclophosphamide (PTCy) in combination with a calcineurin inhibitor and other agents. However, pharmacologic immunosuppression impairs immune reconstitution and heightens the risk of organ toxicity, infection, and disease relapse. Orca-Q is a proprietary, investigational precision engineered allogeneic T-cell immunotherapy designed to promote GVL and GVI and minimize GVHD. Here, we report data from Orca-Q patients with 8/8 HLA matched related donors. Patients recieved either single agent tacrolimus (Arm A) or no immune suppression (Arm C) in a multicenter Phase 1 clinical study (NCT03802695). METHODS Adult patients with high-risk hematologic malignancies eligible for myeloablative conditioning alloHSCT with 8/8 HLA-matched donor were first enrolled on the dose expansion Arm A (with single agent tacrolimus for GVHD prevention; n=18). Due to a low incidence of GVHD, Arm C (with no immunosuppression; n=26) was opened and Arm A closed to enrollment of patients with 8/8 HLA matched donors. Orca-Q was centrally manufactured at an Orca Bio GMP facility (Sacramento, CA) from G-CSF mobilized peripheral blood apheresis. Patients were followed for adverse events for one year post-transplant and for survival thereafter. GVHD-free, relapse-free survival (GRFS) was defined as the time from transplant to the first occurrence of any of these events: grade 3-4 acute GVHD (aGVHD), moderate to severe chronic GVHD (cGVHD), disease relapse, or death from any cause. RESULTS Orca-Q was successfully manufactured and administered to all recipients with a vein-to-vein time of less than 72 hours. As of July 14, 2025, a total of 44 patients with hematological malignancies had been treated, including acute myeloid leukemia, acute lymphocytic leukemia, chronic myeloid leukemia, myelofibrosis, myelodysplastic syndrome, and mixed phenotype leukemia. On Arm A, 14 donors were related and 4 unrelated, compared to Arm B where 12 were related and 14 unrelated. Other patient baseline characteristics were as follows: Arm A: Median age 41 years (range 27-55), 56% male and median follow-up 1531 days (range 66-1825), and Arm C: Median age 60 years (range 20-70), 50% male and median follow-up 234 days (range 5-1418). All patients received myeloablative conditioning. Orca-Q was well tolerated. Overall clinical outcomes were:All patients engrafted neutrophils by day +20 (median 12 days)Overall survival and 1 and 2 years: 90% at 1 year and 86% at 2 yearsRelapse-free survival at 1-year: 87%Moderate-to-severe cGVHD-free survival at 1-year: 85%GRFS at 1-year: 78%Non-relapse mortality at 1-year: 3.4%Relapse incidence at 1-year: 12.7%Grade 3-4 aGVHD at Day +180: 7.1% (6% for Arm A and 8% for Arm C)Moderate-to-severe chronic GVHD at 1 year: 5.9% (12% for Arm A and 0% for Arm C) Orca-Q patients treated without pharmacological prophylaxis (Arm C) demonstrated more rapid immune reconstitution and improved control of infections. Specifically, BMT CTN Grade 2+ infections at 1-year: 33% for Arm A and 17% for Arm C;BMT CTN Grade 3 infection at 1-year: 6% for Arm A and 0% for Arm CMedian absolute CD4 / CD8 cell counts per µL at Day +28: 97 / 94 for Arm A and 102 / 245 for Arm C CONCLUSIONS Orca-Q demonstrates promising efficacy and safety as a precision-engineered T-cell immunotherapy for alloHSCT in patients with high-risk hematologic malignancies. The therapy achieved rapid neutrophil recovery, while maintaining low rates of severe acute GVHD, relapse, and non-relapse mortality across both treatment arms. The low infection rates observed suggest that the cellular composition of Orca-Q can control GVHD and accelerate immune reconstitution even without pharmacological immunosuppression. The Phase 1 study continues to enroll patients to further confirm these results.

Congenital platelet disorders are rare and targeted treatment is usually not possible. Inherited platelet function disorders (iPFDs) can affect surface receptors and multiple platelet responses such as defects of platelet granules, signal transduction, and procoagulant activity. If iPFDs are also associated with a reduced platelet count (thrombocytopenia), it is not uncommon to be misdiagnosed as immune thrombocytopenia. Because the bleeding tendency of the different platelet disorders is variable, a correct diagnosis of the platelet defect based on phenotyping, function analysis, and genotyping is essential, especially in the perioperative setting. In the case of a platelet receptor deficiency, such as Bernard-Soulier syndrome or Glanzmann thrombasthenia, not only the bleeding tendency but also the risk of isoimmunization after platelet transfusions or pregnancy has to be considered. Platelet granule disorders are commonly associated with either intrinsically quantitative or qualitative granule defects due to impaired granulopoiesis, or granule release defects, which can also affect additional signaling pathways. Functional platelet defects require expertise in the clinical bleeding tendency in terms of the disorder when using antiplatelet agents or other medications that affect platelet function. Platelet defects associated with hematological-oncological diseases require comprehensive information about the patient including the clinical implication of the genetic testing. This review focuses on genetics, clinical presentation, and laboratory platelet function analysis of iPFDs with or without reduced platelet number. As platelet defects affecting the cytoskeleton usually show thrombocytopenia, but less impaired or normal platelet functional responses, they are not specifically addressed.

Abstract BACKGROUND Orca-T is an investigational allogeneic T-cell immunotherapy using purified donor regulatory T cells to prevent graft-versus-host disease (GvHD). The randomized phase 3 Precision-T trial (NCT05316701) showed improved moderate-to-severe chronic GvHD-free survival with Orca-T versus standard-of-care transplantation with tacrolimus plus methotrexate prophylaxis. This analysis examines outcomes in prespecified patient subgroups from Precision-T. METHODS In the phase 3 randomized controlled trial, 88 patients received Orca-T and 94 patients received Tac/MTX. Orca-T was produced in a centralized GMP facility and administered in 19 centers across the U.S. Patients were ≤65 years old; had a diagnosis of AML, ALL, MPAL, or MDS with intermediate or high disease risk index (DRI) scores. Patients received a myeloablative conditioning (MAC) regimen (busulfan/fludarabine/thiotepa [BFT] or a TBI-based regimen) and had an 8/8 HLA-matched donor. In this analysis, subgroups of these patients were identified based on differences in demographic and pre-treatment clinical variables including recipient age and sex, donor type, disease type, disease risk, and conditioning regimen. cGFS (the primary endpoint) and GRFS (survival free of aGVHD grades 3-4, moderate-to-severe cGVHD, and relapse) (a secondary endpoint) were compared between treatment groups for each of the subsets. Statistical analyses were performed in R. Log-rank tests and Gray's tests were used to assess survival and cumulative incidence, respectively. RESULTS Per the statistical analysis plan (SAP), the 56th cGFS event triggered a primary analysis of the phase 3 study at a median follow-up of 9 months. The study population had a median age of 43.5 years (range 19 to 65) and 35% were 50 to 65 years old. Primary diseases included AML (53%), ALL (30%), mixed phenotype acute leukemia (MPAL; 3%) and high-risk MDS (14%). Donors were 8/8 HLA-matched (53% sibling, 47% unrelated). In the intention to treat cohorts, Orca-T had a significantly higher cGFS rates at 1-year of 78% (95% CI: 65%, 87%) for Orca-T and 38% (95% CI: 26%, 51%) for Tac/MTX with a hazard ratio 0.26; 95% CI: 0.14, 0.47, p <0.00001). The hazard ratio for GRFS also favored Orca-T at 0.37 (0.23, 0.60). A total of 94% Orca-T patients were alive at 1 year vs 83% of Tac/MTX patients (hazard ratio 0.49; 95% CI 0.20, 1.22, p=0.12). One-year relapse-free survival was comparable between groups (76% for Orca-T vs. 74% for Tac/MTX) while non-relapse mortality favored Orca-T (3.4% vs. 14%, respectively). Subset analyses for several demographic and clinical variables were analyzed, for which the hazard ratios and 95% confidence intervals for cGFS and GRFS were as follows: cGFS Overall >26 (0.14-0.48) Recipient age 24 (0.11-0.54) for ≤50 years, 0.30 (0.12-0.76) for >50 years Recipient sex 24 (0.10-0.56) for men, 0.32 (0.14-0.77) for women Donor type 32 (0.14-0.77) for related, 0.21 (0.09-0.48) for unrelated Disease type 27 (0.13-0.56) for AML, 0.28 (0.06-1.41) for ALL, 0.25 (0.05-1.33) for MDS DRI 21 (0.10-0.44) for intermediate, 0.52 (0.17-1.61) for high Conditioning 35 (0.18-0.67) for BFT, 0.07 (0.01-0.50) for TBI-based GRFS Overall 37 (0.23, 0.59) Recipient age 34 (0.18-0.63) for ≤50 years, 0.44 (0.21-0.91) for >50 years Recipient sex 32 (0.17-0.63) for men, 0.47 (0.24-0.92) for women Donor type 52 (0.28-0.98) for related, 0.24 (0.11-0.50) for unrelated Disease type 39 (0.22-0.69) for AML, 0.35 (0.12-1.02) for ALL, 0.35 (0.09-1.41) for MDS DRI 33 (0.19-0.57) for intermediate, 0.59 (0.24-1.47) for high Conditioning 47 (0.28-0.79) for BFT, 0.15 (0.04-0.51) for TBI-based Notably, overall survival and NRM were similar for patients aged 51-65 as in the entire safety population. For the patients >50y: one-year rates of overall survival were 93.6% (77%, 98%) for Orca-T patients (n=31) versus 80% (61%, 91%) for Tac/MTX patients (n=32), HR = 0.48 (0.12, 1.89), and one-year rates of NRM were 6.4% (1.1%, 19%) with Orca-T vs 16% (5.7%, 31%), HR=0.49 (0.11, 2.06) with Tac/MTX. CONCLUSIONS Orca-T demonstrated improved clinical outcomes overall and across subgroups with varied demographic and clinical features. These data suggest that the benefit of Orca-T extends to older patients and those with high-risk disease.