Absolute Lymphocyte Count Recovery Research Articles

Characterization of lymphopenia and correlating the risk of cytopenias with dose and BM volume irradiated in aggressive B-cell lymphoma patients bridged with radiation therapy for CAR-T cell therapy

IntroductionThe impact of bridging radiation therapy (bRT) for CAR T-cell therapy on absolute lymphocyte count (ALC) kinetics and treatment outcome is unknown. MethodsWe retrospectively reviewed adults with relapsed/refractory aggressive large B-cell lymphoma (LBCL) who received bRT prior to CD-19 CAR-T between 11/2017-4/2023. The change in ALC (ALC Δ RT) was computed by subtracting ALC pre- and post-bRT. Percent bone marrow (%BM) irradiated was calculated by estimating skeletal BM distribution. PFS, DSS, and OS were modeled via Kaplan-Meier. ResultsFifty-one patients received bRT, of which 13 (25.5%) had bulky disease (≥7.5cm). The median bRT dose was 30Gy (range: 4-48Gy); 26 patients (51%) received ≥30Gy. Thirty-one patients (61%) received bRT comprehensively to all disease sites. The median cumulative %BM irradiated was 5.05% (range: 0-50%). At a median follow-up of 10.3 months (95% CI: 7.7-16.4), the 1-year OS, PFS, and DSS rates were 80% (95% CI: 66-99), 78% (64-87), and 82% (68-90), respectively. The incidence of ≥Grade 3 lymphopenia was 33% pre-RT and 68% post-RT, but recovered to 43% at the conditioning chemotherapy (CC) timepoint. There was no correlation between post-RT Grade ≥3 lymphopenia and the receipt of comprehensive bRT, combined modality bridging, ≥30Gy bRT, or bRT to ≥15% of BM (all p>0.2). Among patients with Grade 0-2 lymphopenia pre-RT, increased conversion to Grade ≥3 lymphopenia post-RT correlated with comprehensive or ≥30Gy bRT, but these factors did not impair ALC recovery at CC. There was no association between ALC Δ RT or post-RT ALC with 30 or 90 day response (p>0.25), DSS, PFS, or OS (p>0.3). ConclusionsLymphocyte change during bRT is not associated with CAR-T outcomes. Persistent cytopenia risk following bRT is not associated with bRT to ≥30Gy, ≥15% of BM, or comprehensive coverage. While bRT can be delivered safely, we urge careful treatment planning when incorporating into pre-CAR-T regimens.

Time-Dependent Variation in Immunoparalysis Biomarkers Among Patients with Sepsis and Critical Illness.

Immunoparalysis is a significant concern in patients with sepsis and critical illness, potentially leading to increased risk of secondary infections. This study aimed to perform a longitudinal assessment of immune function over the initial two weeks following the onset of sepsis and critical illness. We compared ex vivo stimulated cytokine release to traditional markers of immunoparalysis, including monocyte Human Leukocyte Antigen (mHLA)-DR expression and absolute lymphocyte count (ALC). A total of 64 critically ill patients were recruited in a tertiary care academic medical setting, including 31 septic and 33 non-septic patients. Results showed that while mHLA-DR expression significantly increased over time, this was primarily driven by the non-septic subset of critically ill patients. ALC recovery was more prominent in septic patients. Ex vivo stimulation revealed significant increases in TNF and IL-6 production over time in septic patients. However, IFNγ production varied with the stimulant used and did not show significant recovery when normalized to cell count. No significant correlation was found between mHLA-DR expression and other immunoparalysis biomarkers. These findings suggest the need for more nuanced immune monitoring approaches beyond the traditional 'sepsis' versus 'non-sepsis' classifications in critically ill patients. It also provided further evidence of a potential window for targeted immunotherapeutic interventions in the first week of critical illness.

Neutrophil to lymphocyte ratio (NTLR) predicts local control and overall survival after stereotactic body radiotherapy (SBRT) in metastatic sarcoma

The neutrophil to lymphocyte ratio (NTLR) and absolute lymphocyte count (ALC) recovery are prognostic across many cancers. We investigated whether NLTR predicts SBRT success or survival in a metastatic sarcoma cohort treated with SBRT from 2014 and 2020 (N = 42). Wilcox Signed Rank Test and Friedman Test compare NTLR changes with local failure vs. local control (N = 138 lesions). Cox analyses identified factors associated with overall survival. If local control was successful, NLTR change was not significant (p = 0.30). However, NLTR significantly changed in patients with local failure (p = 0.027). The multivariable Cox model demonstrated higher NLTR before SBRT was associated with worse overall survival (p = 0.002). The optimal NTLR cut point was 5 (Youden index: 0.418). One-year overall survival in SBRT metastatic sarcoma cohort was 47.6% (CI 34.3%–66.1%). Patients with an NTLR above 5 had a one-year overall survival of 37.7% (21.4%–66.3%); patients with an NTLR below 5 had a significantly improved overall survival of 63% (43.3%–91.6%, p = 0.014). Since NTLR at the time of SBRT was significantly associated with local control success and overall survival in metastatic sarcoma treated with SBRT, future efforts to reduce tumor inhibitory microenvironment factors and improve lymphocyte recovery should be investigated.

CAR19 Therapy Drives Expansion of Clonal Hematopoiesis and Associated Cytopenias

Background: For patients with relapsed/refractory large B-cell lymphomas (rrLBCL), CD19-directed chimeric antigen receptor T cells (CAR19) improve survival compared to autologous hematopoietic cell transplantation (HCT). However, major toxicities of CAR19 therapy include prolonged cytopenias and associated infections. To better understand the impact of CAR19 on such toxicities, we studied a cohort of LBCL patients achieving durable remissions to assess immune recovery after CAR19 treatment. We (1) compared immune reconstitution in HCT vs CAR19 treated patients, (2) performed molecular analysis of post-CAR19 cytopenic marrow specimens, and (3) profiled emergent mutations in cell free DNA (cfDNA) before and after CAR19. Methods & Results: We first propensity matched rrLBCL patients treated at Stanford with either CAR19 (100% axi-cel) or HCT who achieved durable remissions. Patients were matched based on age, sex, prior systemic lines of therapy, and time from infusion. From 471 eligible cases, propensity score matching was successful in 138 (n=69 per arm). When compared to HCT-treated counterparts, CAR19-treated patients had reduced recovery of absolute lymphocyte counts (ALC) and absolute neutrophil counts (ANC; longitudinal regression day 28-800 ANOVA p<0.005), but similar recovery of hemoglobin and platelets. CAR19-treated patients experienced significantly more Grade ≥3 infections in competing risk analyses (HR 2.61, CI 1.26-5.42), and higher non-relapse mortality (log-rank p=0.027). Next, to characterize mechanisms underlying cytopenias after CAR19, we profiled marrow aspirates from cases requiring biopsy due to prolonged cytopenia or clinical concern for myeloid neoplasms. No patient had evidence of lymphoma relapse at the time of biopsy, and all were >60d from CAR19 infusion (median 377d, range 86-1561d). Among 21 patients profiled by DNA sequencing, 18 (86%) had evidence of ≥1 somatic mutation in genes canonically associated with clonal hematopoiesis (CH) in the marrow ( Fig. 1A), with the most recurrently mutated genes being DNMT3A (38%), TP53 (33%), PPM1D (24%), ASXL1 (14%), and TET2 (14%). Among 6 patients diagnosed with and requiring therapy for a myeloid malignancy, all (100%) had a canonical myeloid karyotypic aberration detected by FISH, as compared with 0 in the 14 other evaluable cases ( Fig. 1A). CAR19 cells were proportionately enriched in the marrow relative to paired peripheral blood by flow cytometry (n = 12, median 2.5-fold enrichment, Wilcoxon p<0.001). Using 10x scRNA-Seq, viable CAR19 was detectable in 7 of 8 marrows (88%) and were predominantly CD4+. We hypothesized that CH clones detectable after CAR19 would also be present in pre-CAR19 blood samples and detectable in cfDNA. To test this, we profiled 786 longitudinal samples from 141 patients using CAPP-seq and serially monitored CH clones in cfDNA. Among 141 eligible cases, 40 (28%) were evaluable for CH, in having both pre- and post-CAR19 infusion specimens, while in durable remission (median follow up 967d). Of 51 CH clones detected in post-infusion cfDNA, 46 (90.1%) were also detectable prior to CAR19, typically expanding post-infusion (median = 1.8-fold, Fig. 1B). We next tested whether expanding CH clones showed evidence for selection after CAR19. Strikingly, among 48 recurrently mutated genes tested, DNMT3A and PPM1D showed significant evidence for clonal selection and expansion after CAR19 (Q-value < 0.05). When compared to patients without emerging CH clones, patients with ≥5-fold clonal expansions of canonical CH genes (23% of cases) had reduced ANC, but not ALC, recovery (median ANC=1.43 vs 2.43 at 6-mo, Wilcoxon p<0.001). This association remained significant in multivariate longitudinal regression that included age, sex, prior lines of therapy, and pre-infusion ANC (ANOVA p = 0.007). Conclusion: CAR19 treated patients experience reduced immune reconstitution and higher infection rates than HCT treated counterparts. Bone marrow findings reveal prolonged CAR19 cytopenia to commonly be associated with clonal cytopenia of undetermined significance (CCUS). Despite durable lymphoma remissions, canonical myeloid clonal expansions are common post-CAR19, and associated with myelosuppression. Non-invasive genotyping could aid in early identification of patients at risk for prolonged cytopenias after CAR19 and inform interventions to decrease associated complications.

ALLO-647 for Lymphodepletion in the Allogeneic CAR T Setting: Safety Experience with ALLO-501/501A in Patients (Pts) with Relapsed/Refractory (r/r) Large B-Cell and Follicular Lymphomas

Background: While breakthroughs in hematologic malignancies with autologous CAR T-cell therapies have been met with growing clinical interest due to impressive outcomes, limitations in logistics/manufacturing, quality consistency, and product availability persist. Allogeneic CAR T-cell therapies may circumvent such challenges by providing an off-the-shelf therapeutic option derived from healthy donors. For allogeneic CAR T cells to be successful, there must be a safe and effective way to control host lymphocyte rejection of allogeneic CAR T cells (allo-rejection). ALLO-501 and ALLO-501A are allogeneic anti-CD19 CAR T-cell products that use Cellectis technologies' TALEN® gene editing to disrupt both the TCRα constant ( TRAC) and CD52 genes. CD52 disruption specifically permits use of ALLO-647, an anti-CD52 antibody, for the transient and selective depletion of host lymphocytes that enables ALLO-501 and ALLO-501A to proliferate after infusion without rapid allo-rejection. Updated phase 1 data for ALLO-501 (ALPHA; NCT03939026) and ALLO-501A (ALPHA2; NCT04416984) showed that administration of anti-CD19 allogeneic CAR T product following use of lymphodepletion that includes ALLO-647 plus fludarabine and cyclophosphamide provided durable responses and an acceptable safety profile in CAR T-cell-naive pts with r/r large B-cell lymphoma (LBCL; Locke FL, et al. ASCO 2023; #2517). Herein, we provide safety results of ALLO-647 in pts with r/r LBCL and follicular lymphoma (FL). Methods: Pts with r/r LBCL and FL enrolled in ALPHA and ALPHA2 studies received a 3 to 5-day lymphodepletion regimen consisting of fludarabine 30 mg/m 2 and cyclophosphamide 300-500 mg/m 2 (FC) and 39, 60, or 90 mg of ALLO-647 in divided doses. ALLO-501/ALLO-501A were administered after the completion of lymphodepletion. Incidence rates of grade ≥3 cytopenias (neutropenia, thrombocytopenia, anemia and pancytopenia) were assessed at 3 timepoints (Study Day 28, Day 56, and Month 4). Pts underwent weekly cytomegalovirus (CMV) monitoring. Leukocyte reconstitution was evaluated following lymphodepletion and CAR T-cell infusion. Results: As of April 20, 2023, 87 pts with r/r LBCL (n=61) and FL (n=26) were treated with ALLO-647 and included in the analysis (median age, 64 years; median number of prior regimens, 3). In total, 11 (13%), 39 (45%), and 37 (43%) pts received 39, 60, and 90 mg ALLO-647, respectively. Among the LBCL pts, 33 were CAR T-cell-naive and treated with product manufactured using the Phase 2 process. Median follow-up was 29.5 months (range, 6.8-47.5). The most common treatment-emergent adverse events (TEAEs), assessed from the time of first dose of lymphodepletion, included neutropenia (79%), anemia (61%), infusion-related reactions (IRRs, 55%), and thrombocytopenia (53%). The most common grade ≥3 TEAEs included neutropenia (74%), anemia (38%), and thrombocytopenia (38%). The proportion of pts experiencing grade ≥3 cytopenias decreased over time from Day 28 (29%) to Day 56 (20%) to Month 4 (15%), which was consistent across all lymphoma pt subgroups. ALLO-647 IRRs were typically low grade, except for 5 (6%) grade 3 events; all IRRs were managed with supportive care measures. After treatment with ALLO-501/501A, 20 pts (23%) experienced cytokine release syndrome events, which were low grade except for 1 (1%) grade 3 event. No GvHD, grade ≥3 immune effector cell-associated neurotoxicity syndrome events, or progressive multifocal leukoencephalopathy were reported. Any grade and grade ≥3 infections were reported in 50 pts (58%) and 18 pts (21%), respectively. Two pts had (2%) fatal infectious events (COVID-19 pneumonia and pneumonia, n=1 each) as previously reported. The most common infection was CMV reactivation (any grade, n=22 [25%]; grade 3, n=8 [9%]). Following lymphodepletion, the median time to absolute neutrophil count and absolute lymphocyte count recovery to grade <4 was 7 days and 28 days, respectively. T-cell counts exhibited a steady increase over time, with the majority of pts achieving full T-cell recovery (return to baseline levels) by Month 6. Detailed pharmacokinetics and pharmacodynamics data will be presented. Conclusions: These data suggest allogeneic CAR T-cell products administered following lymphodepletion consisting of FC and ALLO-647 can provide a safe and tolerable alternative to autologous CAR T-cell therapy.

Initial Report of a Randomized Trial Comparing Conventional vs. Novel Treatment Planning Technique to Ameliorate Immunosuppression from Lung SBRT

SBRT is highly effective against early-stage non-small cell lung cancer. Radiation Therapy (RT) is known to modulate the immune system and contribute to the generation of anti-tumor T cells and stimulate T cell infiltration into tumors. However, this anti-tumor activity is offset by radiation-induced immunosuppression (RIIS) which results in lower tumor control and survival. Lymphocytes are highly radiosensitive and RIIS means destroying existing as well as newly created cytotoxic and helper T lymphocytes. We hypothesized that optimizing RT treatment planning by considering circulating blood and lymphatics as a critical Organ at Risk (OAR) may mitigate RIIS. We conducted an IRB approved NCI funded clinical trial for 50 early-stage lung cancer patients treated with SBRT alone, from 2020 to 2023, to investigate the ability to reduce RIIS by reducing dose to circulating blood and lymphatics with the aid of a predictive algorithm. All SBRT plans adhered to treatment parameters from RTOG 0813 (central) or RTOG 0915 (peripheral). Patients were randomized to two arms: experimental optimization for RIIS (to reduce dose to blood and lymphatic rich organs) versus standard SBRT planning (without optimization for RIIS). Peripheral blood samples were collected at baseline, end of Tx, 4 weeks and 6 months post Tx. Patients with baseline absolute lymphocyte counts (ALC) less than 0.5x109 cells/L were ineligible for the trial. Data acquired for all blood cell types as well as lymphocyte sub populations CD3+, CD4+, CD8+, CD19+, CD56+. Two sample t-test was used to determine the statistical significance between the cohorts at the time points. The standard arm had an ALC reduction of 28% at one week post Tx and a nadir at 4 weeks with a 34% reduction. Absolute percentage reductions in ALC from baseline in the optimized arm compared to the standard arm are: end of treatment point (13%, p = 0.03), 4 weeks (12%, p = 0.08), 6 months (15%, p = 0.1), and all three time points together 13% (p = 0.001). ALC recovery appears to be faster in the optimized arm. Radiation induced suppression of all blood cell types are also reduced in the optimized arm with respect to standard arm (relative percentages): ALC (34%), WBC (47%), RBC (46%), platelets (40%), monocytes (100%), and neutrophils (62%) at 4-week mark. Average percentage reductions on integral doses, and V5 (volume receiving a 5 Gy dose) of optimized compared to standard plans are: aorta: 26%, 41% heart: 8%, 33%, vena cava: 32%, 52%, T spine: 51%, 81%, lymph nodes: 35%, 57%, total lung- ITV: 1.6%, 1%, body: 10%, 14%. For the first time, we have shown that it is possible to reduce RIIS in a statistically significant manner, compared to standard of care, via optimized RT planning using a predictive model. This has implications in increasing the efficacy of immunotherapy by preserving the existing tumor reactive T cells in the immune system to enhance anti-tumor activity, and in reducing hospitalizations and improving survival.

Absolute lymphocyte counts (ALC) recovery and risk of viral reactivation in the setting of haploidentical hematopoietic stem cell transplant.

e19065 Background: The impact of early absolute lymphocyte repopulation after allogeneic hematopoietic stem cell transplant has historically been shown to predict the risk of post-transplant infection, and subsequently, non-relapse mortality (NRM). Previous studies have shown that ALC recovery after allogeneic stem cell transplant is associated with risk of viral reactivation and survival. In this study we aim to investigate the role of ALC recovery in the contemporary era with myeloablative haploidentical hematopoietic stem cell transplant (HI-HSCT). Methods: We retrospectively analyzed adult patients at University of Southern California (USC) Norris Cancer Hospital who received myeloablative conditioning haplo-HSCT (Fludarabine with 12 Gy of radiation) from 2014 to 2020. The primary endpoint was correlation between ALC recovery day 21 and risk of viral reactivation including cytomegalovirus (CMV), Epstein-Barr Virus (EBV) and BK virus. ALC recovery cut off was chosen to be 175/uL on day +21 and 500/uL on day +60 based on prior reports. Results: 58 patients were identified as recipients of MAC haploidentical-HSCT. 17 had ALC recovery at day +21. Mean age was 49 years, 31 (53.4%) were males and 27 (46.6%) were females. 41 (70%) patients were Hispanic, 12 (20%) were non-Hispanic White, and the majority had AML (51%). 76% received > 5*106/kg CD34+ cell dose and 78% received CD3 + cell dose < 3*108/kg. Serum CMV, EBV and urine BK virus were detected in 38 (65.5%), 8 (15.7%) and 11 (32.4%) respectively. Clinically significant CMV reactivation (required treatment with antiviral therapy) was detected in 26 (44.8%) patients. Lack of ALC recovery on day +21 did not show correlation with CMV, EBV and BK virus reactivation. Also, the risk of CMV reactivation was not related to day +60 ALC recovery (p-value = 0.469). On univariate analysis, ALC recovery day +21, day +60, and CMV reactivation did not show correlation with overall survival. In multivariate analysis when adjusted for age and pre-transplant CMV status, higher CD 3+ cell dose of > 3*108/kg was associated with reduced risk of CMV reactivation HR = 0.35 (0.15-0.85) p-value = 0.02. Conclusions: Previous studies have established ALC recovery as a predictor of better outcome. This has not been established in patients undertaking myeloablative HI-HSCT. Our study shows that lack of ALC recovery on day +21 does not affect CMV, EBV and BK virus reactivation and risk of CMV reactivation does not correlate with day +60 ALC recovery. Also, ALC recovery and CMV reactivation does not impact overall survival. The use of Letermovir, effective CMV therapies and close viral surveillance in contemporary practice is likely responsible for mitigating poor outcomes with CMV reactivation. Graft composition needs to be studied prospectively, as higher CD3+ cell dose may present an opportunity to reduce CMV reactivation in HI-HSCT.

Predictive role of absolute lymphocyte count in daratumumab-treated patients with relapsed/ refractory multiple myeloma.

Daratumumab has shown an encouraging antitumor effect in patients with multiple myeloma (MM), and was known to alter the immune properties by off-targeting immunosuppressive cells. Here, we aimed to evaluate the change in absolute lymphocyte count (ALC) as a surrogate marker for predicting survival outcomes of patients treated with daratumumab. Between 2018 and 2021, the medical records of patients with relapsed/refractory MM (RRMM) treated with daratumumab monotherapy at 10 centers in South Korea were reviewed. We collected the ALC data at pre-infusion (D0), day 2 after the first infusion (D2), and prior to the third cycle of daratumumab therapy (D56). Fifty patients who were administered at least two cycles of daratumumab were included. Overall response rate was 54.0% after two cycles of daratumumab treatment. On D2, almost all patients experienced a marked reduction in ALC. However, an increase in ALC on D56 (ALCD56) was observed in patients with non-progressive disease, whereas failure of ALC recovery was noted in those with progressive disease. Patients with ALCD56 > 700/μL (n = 39, 78.0%) had prolonged progression- free survival (PFS) and overall survival (OS) than those with ALCD56 ≤ 700/μL (median PFS: 5.8 months vs. 2.6 months, p = 0.025; median OS: 24.1 months vs. 6.1 months, p = 0.004). In addition, ALCD56 >700/μL was a significant favorable prognostic factor for PFS (hazard ratio [HR], 0.22; p = 0.003) and OS (HR, 0.23; p = 0.012). Increase in ALC during daratumumab treatment was significantly associated with prolonged survival outcomes in patients with RRMM. The ALC value can predict clinical outcomes in patients treated with daratumumab.

Absolute Lymphocyte Count Is an Independent Survival Predictor in Patients with Acute Myeloid Leukemia Treated with Intensive Chemotherapy

Background Absolute lymphocyte count (ALC)is known to be an independent prognostic factor for overall survival (OS) in patients receiving autologous transplantation for Hodgkin's and non-Hodgkin's lymphomas, multiple myeloma and breast cancer. In acute myeloid leukemia (AML) patients, enhanced ALC recovery after intensive chemotherapy (IC) has been associated with superior OS and leukemia-free survival (LFS). However, few if any data correlated ALC recovery with novel therapies as well as with updated prognostic factors, such as European Leukemia Net (ELN) risk-classification. Aims Our study aims at evaluating the predictive value of ALC recovery in newly diagnosed AML patients who obtained complete remission (CR) to IC by analysing its impact through different patient subgroups according to therapy response, type of chemotherapy regimen and the use of allogeneic stem cell transplantation (HSCT). Methods We evaluated 156 responsive AML patients treated with IC at Bologna Seràgnoli Hematology Institute since 2007. We defined 4 ALC time-points (TPs): at 15, 21 and 28 days from the start of induction chemotherapy and before consolidation therapy (CC). ALC cut-off was established at 500/mm3. In addition to the assessment of the single TP, patients were also grouped in those who obtained ≥500/mm3ALC in all 4 TPs and those who had<500/mm3ALC in at least one TP. Median follow-up was 65 months. Results When ALC recovery was assessed in whole population, both at single TPs and ALC recovery achievement at all TPS vs others, no statistically significant association with better OS and LFS has been shown. Then we subdivided patients according to IC regimen administered: "3+7-based" regimen (52,6%) versus those who were treated with "fludarabine-based" regimen (47,4%). Considering "3+7" patients, at TP day 15 a significant correlation with OS (p=0.047) of patients with ≥500/mm3ALC (34,6%) vs those who had<500/mm3ALC (17,9%) was observed (instead for ALC-21 p value was 0.078). A similar trend (p=0.021) was shown for those who obtained ≥500/mm3 ALC in all 4 TPs (27,5%) compared to those who had <500/mm3ALC in at least one TP (25%). Of note, FLT3-ITD positive patients in this subgroup, who achieved early ALC recovery at day 15 and at all 4 TPs assessment, had better outcomes, despite with p=0.27 and p=0.19 respectively, because of the meager number of patients. Among patients treated with "fludarabine-based" regimens, ALC recovery assessment did not show remarkable correlation with outcome, even when considering the NPM1 mutated subgroup. We, then, analysed in whole population the impact of post-chemotherapy ALC recovery in patients who received HSCT (63,5%) vs those who did not (36,5%) (Fig.1). As expected, transplanted patients had globally better outcome than patients who received only chemotherapy. In patients who received HSCT the impact of ALC recovery after chemotherapy was minimal (blue and purple curve). In contrast, patients who had ALC <500/mm3 ALC in at least one TP and did not undergo HSCT had the worst outcome (green curve). Interestingly, patients who were not transplanted but had ≥500/mm3ALC in all 4 TPs (red curve) had a better OS, comparable to transplanted patients. Conclusions Our study indicates ALC recovery after IC as a promising survival predictor in AML patients, especially in those who do not undergo HSCT. It is reasonable to underline the impact of fludarabine, as for its lymphocytolytic effect, in order to explain the different results in the subgroup fludarabine-based. The outcome trends in different prognostic subgroups according to ELN classification, such as FLT3, NPM1, adverse cytogenetics, need a caseload expansion. In the path that aims to investigate the complex interaction between leukemia and the immune system, our study may provide the clinical rationale for the construction of an immunological score to be integrated in the current disease-centered risk classification system. Future studies in larger cohorts addressing the impact of ALC recovery in association with the use of novel agents and minimal residual disease status are highly warranted. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Immune Recovery Post BCMA CAR-T: Implications for Infection Prophylaxis and Vaccinations

Immune Recovery Post BCMA CAR-T: Implications for Infection Prophylaxis and Vaccinations

Immune reconstitution after allogenic stem cell transplantation: An observational study in pediatric patients

IntroductionThe immune reconstitution (IR) after the allogenic hematopoietic stem cell transplantation (allo-HSCT) is a progressive process intrinsically correlated to the therapeutic success. It is essential to understand the interfering factors in IR to prevent the HSCT-related mortality. MethodsWe retrospectively evaluated the clinical outcomes, absolute lymphocyte counts (ALCs) and lymphocyte subtypes at different time-points of 111 pediatric patients with allogeneic HSCT for malignant and non-malignant diseases from 2013 to 2018. ResultsThe ALCs gradually increased on D+30, D+100, and D+180 (medians 634/μL, 1022/μL and 1541/μL, respectively). On D+100, the CD3+CD8+ achieved the highest recovery rate (68%), followed by the CD16+CD56+ (47%), CD3+CD4+ (39%) and CD19+ (8%). The adequate ALC recovery was associated with age < 8 years, bone marrow grafts, myeloablative conditioning, non-use of serotherapy and non-haploidentical donors. The ALC and CD3+CD8+ on D+100 counts were higher in patients with the cytomegalovirus infection. The CD3+CD4+ recovery was associated with an age < 8 years, a non-malignant disease and a lower incidence of acute graft-versus-host disease ≥ grade 2. Furthermore, the ALC recovery on D+100 resulted in a higher overall survival, regardless of the disease type (HR 3.65, 1.05 - 12.71, p = 0.04). ConclusionSeveral factors influenced the IR after the allo-HSCT. The ALC ≥ 500/μL on D+100 was a simple IR predictor of survival, easily available to resource-limited centers.

Transitioning From S1P Receptor Modulators to B Cell-Depleting Therapies in Multiple Sclerosis: Clinical, Radiographic, and Laboratory Data.

Background and ObjectivesPatients with multiple sclerosis (MS) transition from oral sphingosine-1-receptor (S1P) modulators to anti-CD20 therapies for several circumstances. Optimal timing of this transition is uncertain, given competing concerns of rebound disease activity and ensuring immune reconstitution. The objective of this study was to evaluate the relationship between inflammatory activity and the transition period from fingolimod to anti-CD20 therapies in a real-world MS cohort.MethodsMedical records were reviewed for all patients at our center transitioning from fingolimod to rituximab or ocrelizumab between 2010 and October 2020. Time periods reviewed were the following: before fingolimod discontinuation, interval between fingolimod and anti-CD20 treatments, and after the first anti-CD20 infusion. The primary outcome was clinical relapses; MRI activity, time to absolute lymphocyte count (ALC) recovery, and infections were secondary. Clinical and demographic factors significant in univariable analyses were included in multivariable analyses.ResultsTransition data were available for 108 patients (68.5% women, 68.5% relapsing-remitting MS, mean age 44.6 years). The median (interquartile range) interval between fingolimod and anti-CD20 therapy was 28 (1–115.2) days. Six of 51 patients (11.8%) with intervals >1 month and 0/57 patients with shorter intervals experienced a relapse (MRI confirmed) within 6 months of fingolimod discontinuation. In the year following anti-CD20 initiation, 4/108 patients (3.7%) experienced a relapse (median 214.5 days after infusion). An additional 7% of those undergoing contrast-enhanced MRIs developed Gd+ lesions. ALC normalized following treatment switch in 89/92; the interval between treatments was unrelated to ALC recovery or infection.DiscussionDelaying anti-CD20 start to monitor ALC after S1P modulator discontinuation may not be necessary and could increase rebound risk. ALC monitoring could instead occur after a rapid switch to anti-CD20 treatment.

Outcomes and Toxicities of Modern Combined Modality Therapy with Atezolizumab Plus Bevacizumab and Radiation Therapy for Hepatocellular Carcinoma.

Simple SummaryHepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide with slow progress in the development of effective therapies. The breakthrough IMbrave150 trial established atezolizumab plus bevacizumab as the standard of care first-line therapy for patients with unresectable/advanced HCC, demonstrating improved overall survival. Radiation therapy (RT) is a locoregional treatment that may prevent morbidity from tumor-related vascular compromise and associated liver failure. There is no documented evidence yet describing the safety and outcomes of combination RT and atezolizumab/bevacizumab. In the retrospective review of our experience, we identified 21 patients with advanced HCC who underwent liver-directed RT with atezolizumab/bevacizumab. From our findings, the treatment is well-tolerated, safe, and does not potentiate liver failure. There were uncommon autoimmune or GI bleeding events in some patients, mostly unrelated to RT. Post-RT absolute lymphocyte counts (ALC) improved more quickly with atezolizumab/bevacizumab than they did without, which may be a favorable treatment prognosticator.Atezolizumab plus bevacizumab has become frontline therapy for unresectable HCC. The compatibility of atezolizumab/bevacizumab with liver-directed RT has not been reported. Methods: HCC patients treated with liver-directed RT and atezolizumab/bevacizumab between 1/2020–11/2021 were included. Toxicity and outcomes were retrospectively recorded. For ALCs, we matched the analysis to a previously cohort of RT-treated HCC patients who did not receive atezolizumab/bevacizumab. Survival and time-to-liver-failure were analyzed using Kaplan–Meier. Results: Of 21 patients, with a median follow-up of 9.5 months, the median OS was 16.1 months. Post-RT, all patients had reduced tumors or treatment response. There were no ≥Grade 3 RT-related toxicities. Autoimmune complications occurred in two patients (9.5%), and GI bleeding in three patients (14.3%). Liver function remained stable post-RT. There was a marked decrease in ALCs immediately post-RT (post-RT/pre-RT ratio 47.3%, p < 0.0001), restored by 1 month to pre-treatment baseline (1-month post-RT/pre-RT ratio 95.1%, n.s.). Compared to HCC patients treated with RT alone, post-RT ALC recovery was faster with atezolizumab/bevacizumab (p = 0.009). Conclusion: In this first reported experience of RT with modern systemic therapy for HCC, combination therapy is safe and well-tolerated. As a favorable prognosticator, there appears to be faster recovery of ALC among patients who received RT with atezolizumab/bevacizumab.

POPULATION PHARMACOKINETICS AND PHARMACODYNAMICS OF OZANIMOD IN ULCERATIVE COLITIS

Abstract BACKGROUND Ozanimod is an oral small molecule sphingosine 1-phosphate receptor modulator approved for relapsing forms of multiple sclerosis (RMS) and moderately to severely active ulcerative colitis (UC) and under development for Crohn’s disease. Ozanimod and its major active metabolites CC112273 and CC1084037 block lymphocyte egress from lymphoid tissues, reducing the absolute lymphocyte count (ALC) in blood. To characterise the influence of patient characteristics on ALC response, a population pharmacokinetic/pharmacodynamic (PK/PD) analysis was conducted. METHODS A nonlinear mixed-effects Emax model described the ALC time course and relationship to CC112273 concentrations in healthy subjects and patients with UC or RMS. The analysed data included 34,449 ALC values obtained from 4122 subjects enrolled in 11 Phase 1, 2, and 3 clinical studies. The effect of age, sex, smoking status, disease type, body weight, total bilirubin, and baseline ALC on the maximum ALC reduction (Emax) and half-maximal concentration (EC50) were investigated. Simulations of typical ALC reductions for healthy subjects and patients with UC or RMS receiving 0.5 or 1 mg ozanimod were conducted to explore the influence of smoking and assess the time for ALC recovery. RESULTS Increasing CC112273 concentrations were associated with reductions in ALC to a maximum of 74% from baseline, with an estimated EC50 of 2.8 nM CC112273. Healthy subjects, females, and higher body weights were associated with larger ALC Emax (Figure 1), while healthy subjects, increased age, nonsmokers and higher baseline ALC were associated with an increased EC50 (Figure 2). UC patients receiving 0.5 mg and 1 mg ozanimod HCl are predicted to have mean ALC reductions of 46.1% and 57.2%, respectively, with similar reductions for RMS patients of 48.0% and 57.4%. Smoking was associated with a 27.2% reduction in the ALC EC50, which partially offsets the reduced plasma CC112273 concentrations in smokers. Simulations show that 1 mg ozanimod has comparable ALC reductions of 57.4% in nonsmokers and 52.7% in smokers. Upon discontinuing ozanimod 1 mg in UC patients, a mean recovery time to normal (1 x 109/L ALC count) of 32.8 days was predicted, with 90% of the population recovering in 3 months. Overall results were consistent with findings from clinical trials. CONCLUSION Population analysis demonstrated a similar PK/PD relationship for ALC reductions in patients with RMS and UC. Smoking was not associated with substantial difference in ALC, consistent with no loss of efficacy in smokers. Upon discontinuation of ozanimod treatment, the majority of UC and RMS patients will recover lymphocyte counts to normal within 3 months.

POPULATION PHARMACOKINETICS AND PHARMACODYNAMICS OF OZANIMOD IN ULCERATIVE COLITIS

Ozanimod is an oral small molecule sphingosine 1-phosphate receptor modulator approved for relapsing forms of multiple sclerosis (RMS) and moderately to severely active ulcerative colitis (UC) and under development for Crohn’s disease. Ozanimod and its major active metabolites CC112273 and CC1084037 block lymphocyte egress from lymphoid tissues, reducing the absolute lymphocyte count (ALC) in blood. To characterise the influence of patient characteristics on ALC response, a population pharmacokinetic/pharmacodynamic (PK/PD) analysis was conducted. A nonlinear mixed-effects Emax model described the ALC time course and relationship to CC112273 concentrations in healthy subjects and patients with UC or RMS. The analysed data included 34,449 ALC values obtained from 4122 subjects enrolled in 11 Phase 1, 2, and 3 clinical studies. The effect of age, sex, smoking status, disease type, body weight, total bilirubin, and baseline ALC on the maximum ALC reduction (Emax) and half-maximal concentration (EC50) were investigated. Simulations of typical ALC reductions for healthy subjects and patients with UC or RMS receiving 0.5 or 1 mg ozanimod were conducted to explore the influence of smoking and assess the time for ALC recovery. Increasing CC112273 concentrations were associated with reductions in ALC to a maximum of 74% from baseline, with an estimated EC50 of 2.8 nM CC112273. Healthy subjects, females, and higher body weights were associated with larger ALC Emax (Figure 1), while healthy subjects, increased age, nonsmokers and higher baseline ALC were associated with an increased EC50 (Figure 2). UC patients receiving 0.5 mg and 1 mg ozanimod HCl are predicted to have mean ALC reductions of 46.1% and 57.2%, respectively, with similar reductions for RMS patients of 48.0% and 57.4%. Smoking was associated with a 27.2% reduction in the ALC EC50, which partially offsets the reduced plasma CC112273 concentrations in smokers. Simulations show that 1 mg ozanimod has comparable ALC reductions of 57.4% in nonsmokers and 52.7% in smokers. Upon discontinuing ozanimod 1 mg in UC patients, a mean recovery time to normal (1 x 109/L ALC count) of 32.8 days was predicted, with 90% of the population recovering in 3 months. Overall results were consistent with findings from clinical trials. Population analysis demonstrated a similar PK/PD relationship for ALC reductions in patients with RMS and UC. Smoking was not associated with substantial difference in ALC, consistent with no loss of efficacy in smokers. Upon discontinuation of ozanimod treatment, the majority of UC and RMS patients will recover lymphocyte counts to normal within 3 months.Figure 2Population PK/PD ALC Full Model Covariate Effects on EC50View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Optimal time and threshold of absolute lymphocyte count recovery as a prognostic factor after single-unit cord blood transplantation in adults.

We retrospectively evaluated the optimal time and threshold of absolute lymphocyte count (ALC) recovery as a prognostic factor in 174 adult patients who received single‐unit cord blood transplantation (CBT) at our institute. We analyzed the impact of ALC ≥300, ≥600, and ≥900/μl by 30 and 60 days on transplant outcomes. Multivariate analysis showed that only ALC ≥300/μl at 60 days was significantly associated with overall mortality (hazard ratio, 0.24; p = 0.001) following CBT. The optimal time point to use ALC recovery as a prognostic tool following CBT could be later than those following adult donor transplantation.

Chronological Analysis of Acute Hematological Outcomes after Proton and Photon Beam Craniospinal Irradiation in Pediatric Brain Tumors.

PurposeThis study aimed to compare the early hematological dynamics and acute toxicities between proton beam craniospinal irradiation (PrCSI) and photon beam craniospinal irradiation (PhCSI) for pediatric brain tumors.Materials and MethodsWe retrospectively reviewed patients with pediatric brain tumors who received craniospinal irradiation (CSI). The average change in hemoglobin levels (ΔHbavg), absolute lymphocyte counts (ΔALCavg), and platelet counts (ΔPLTavg) from baseline values was evaluated and compared between the PrCSI and PhCSI groups at 1 and 2 weeks after the initiation of CSI, 1 week before and at the end of radiotherapy, and 3–4 weeks after the completion of radiotherapy using t-test and mixed-model analysis.ResultsThe PrCSI and PhCSI groups consisted of 36 and 30 patients, respectively. There were no significant differences in ΔHbavg between the two groups at any timepoint. However, ΔALCavg and ΔPLTavg were significantly lower in the PhCSI group than in PrCSI group at every timepoint, demonstrating that PrCSI resulted in a significantly lower rate of decline and better recovery of absolute lymphocyte and platelet counts. The rate of grade 3 acute anemia was significantly lower in the PrCSI group than in in the PhCSI group.ConclusionPrCSI showed a lower rate of decline and better recovery of absolute lymphocyte and platelet counts than PhCSI in the CSI for pediatric brain tumors. Grade 3 acute anemia was significantly less frequent in the PrCSI group than in the PhCSI group. Further large-scale studies are warranted to confirm these results.

P315 Population pharmacokinetics and pharmacodynamics of ozanimod in ulcerative colitis

Abstract Background Ozanimod is an oral small molecule sphingosine 1-phosphate receptor modulator approved for relapsing forms of multiple sclerosis (RMS) and under development for ulcerative colitis (UC) and Crohn’s disease. Ozanimod and its major active metabolites CC112273 and CC1084037 block lymphocyte egress from lymphoid tissues, reducing the absolute lymphocyte count (ALC) in blood. To characterise the influence of patient characteristics on ALC response, a population PK/PD analysis was conducted. Methods A nonlinear mixed-effects Emax model described the ALC time course and relationship to CC112273 concentrations in healthy subjects and patients with UC or RMS. The analysed data included 34,449 ALC values obtained from 4122 subjects enrolled in 11 Phase 1, 2, and 3 clinical studies. The effect of age, sex, smoking status, disease type, body weight, total bilirubin, and baseline ALC on the maximum ALC reduction (Emax) and half-maximal concentration (EC50) were investigated. Simulations of typical ALC reductions for healthy subjects and patients with UC or RMS receiving 0.5 or 1 mg ozanimod were conducted to explore the influence of smoking and assess the time for ALC recovery. Results Increasing CC112273 concentrations were associated with reductions in ALC to a maximum of 74% from baseline, with an estimated EC50 of 2.8 nM CC112273. Healthy subjects, females, and higher body weights were associated with larger ALC Emax (Figure 1), while healthy subjects, increased age, nonsmokers and higher baseline ALC were associated with an increased EC50 (Figure 2). UC patients receiving 0.5 mg and 1 mg ozanimod HCl are predicted to have mean ALC reductions of 46.1% and 57.2%, respectively, with similar reductions for RMS patients of 48.0% and 57.4%. Smoking was associated with a 27.2% reduction in the ALC EC50, which partially offsets the reduced plasma CC112273 concentrations in smokers. Simulations show that 1 mg ozanimod has comparable ALC reductions of 57.4% in nonsmokers and 52.7% in smokers. Upon discontinuing ozanimod 1 mg in UC patients, a mean recovery time to normal (1 x 109/L ALC count) of 32.8 days was predicted, with 90% of the population recovering in 3 months. Overall results were consistent with findings from clinical trials. Conclusion Population analysis demonstrated a similar PK/PD relationship for ALC reductions in patients with RMS and UC. Smoking was not associated with substantial difference in ALC, consistent with no loss of efficacy in smokers. Upon discontinuation of ozanimod treatment, the majority of UC and RMS patients will recover lymphocyte counts to normal within 3 months.

Very-Short-Term Sleep Deprivation Slows Early Recovery of Lymphocytes in Septic Patients.

Sleep plays an important role in immune function. However, the effects of very-short-term sleep deprivation on the early recovery of immune function after sepsis remain unclear. This study was conducted in the intensive care unit to investigate the effects of 2 consecutive days of sleep deprivation (SD) on lymphocyte recovery over the following few days in septic patients who were recovering from a critical illness. The patients' self-reports of sleep quality was assessed using the Richards–Campbell Sleep Questionnaire at 0 and 24 h after inclusion. The demographic, clinical, laboratory, treatment, and outcome data were collected and compared between the good sleep group and poor sleep group. We found that 2 consecutive days of SD decreased the absolute lymphocyte count (ALC) and ALC recovery at 3 days after SD. Furthermore, post-septic poor sleep decreased the plasma levels of atrial natriuretic peptide (ANP) immediately after 2 consecutive days of SD. The ANP levels at 24 h after inclusion were positively correlated with ALC recovery, the number of CD3+ T cells, or the number of CD3+ CD4+ cells in the peripheral blood on day 5 after inclusion. Our data suggested that very-short-term poor sleep quality could slow down lymphocyte recovery over the following few days in septic patients who were recovering from a critical illness. Our results underscore the significance of very-short-term SD on serious negative effects on the immune function. Therefore, it is suggested that continuous SD or several short-term SD with short intervals should be avoided in septic patients.

Hypomagnesemia Is Associated with an Increased Risk of Failure in Patients Diffuse Large B-Cell Lymphoma Undergoing Autologous Stem Cell Transplantation

Magnesium is an essential element that is involved in the regulation of cell growth, division and differentiation. Epidemiologic studies have demonstrated that a diet poor in magnesium is associated with an increased risk of developing cancer. There are few studies investigating whether magnesium deficiency is associated with a poor prognosis in lymphomas. The recent discovery of X-linked immunodeficiency with magnesium defect, Epstein-Barr virus, and neoplasia (XMEN) disease, suggests a role of magnesium in the development of hematologic malignancies and lymphocyte function. Furthermore, a recently published study found that hypomagnesemia prior to chemotherapy is associated with inferior overall survival (OS) in patients with Burkitt Lymphoma. We hypothesized that low magnesium levels prior to autologous hematopoietic stem cell transplant (AHSCT) may lead to inferior outcomes via impaired lymphocyte recovery. We evaluated whether low serum magnesium levels were associated with inferior survival in patients with relapsed or refractory diffuse large B cell lymphoma (DLBCL) who underwent autologous hematopoietic stem cell transplant (AHSCT) between January 1998 and May 2020 using a retrospective study design. We cross-referenced our search with patients who had a magnesium level as part of their pre-transplant workup between 7 and 28 days prior to their first transplant. Two-sided Wilcoxon rank sum test and Chi square/Fischer's exact test were used to compare the continuous and categorical variables, respectively. Kaplan-Meier and log-rank tests were used to perform all time to event analysis. Hazard ratios (HR) with confidence intervals (CI) were calculated using Cox-proportional hazards. Our study included 581 patients of which 82 (14.1%) had hypomagnesemia (magnesium &amp;lt; 1.7 mg/dL) prior to AHSCT. Our study found that hypomagnesemia was associated with inferior OS and event-free survival (EFS) defined as re-transplant, relapse or death, compared to those with a normal magnesium level; median OS: 7.3 years (95% CI: 2.91 - upper limit not estimable) versus 9.7 years (95% CI: 6.92 - 12.3 years), p=0.0041; and median EFS: 3.9 years (95% CI: 1.63 - 8.98 years) versus 6.29 years (95% CI: 4.73 - 8.95 years), p = 0.016 respectively(B). Higher serum magnesium (HR 0.199 per doubling, 95% CI 0.078 - 0.503; p&amp;lt;0.001) and higher albumin (HR 0.090 per doubling, 95% CI 0.021 - 0.394; p=0.001) were associated with lower mortality rates, and higher creatinine (HR 1.669 per doubling, 95% CI 1.03 - 2.52; p=0.04) was associated with greater mortality up to 1 year post-transplantation. In a multivariate Cox regression excluding albumin, hypomagnesemia (p &amp;lt; 0.001) and elevated creatinine (p = 0.038) were independent predictors of poor overall survival(A). There was no significant difference between day 15 absolute lymphocyte count between patients with normal magnesium levels and low serum magnesium levels prior to their conditioning regimen. Although we hypothesized that we would find a significant difference between 15 day absolute lymphocyte count recovery and hypomagnesemia, this was not apparent. However, magnesium is an important nutrient for immune function and immune recovery is important after the bone marrow is restored post ablative therapy. Thus, low serum magnesium levels may lead to impaired OS and EFS via impaired lymphocyte function. In vitro studies will be necessary to understand this mechanism further. Magnesium may simply be a marker of illness and replacement of magnesium may not improve outcomes. However, further investigations are needed to determine whether outcomes would improve with replacement of magnesium in patients with hypomagnesemia, which our study did not address. Overall, our preliminary data suggests that hypomagnesemia is an independent prognostic factor and predictor of inferior OS and EFS in this cohort of patients. Figure Disclosures Ansell: ADC Therapeutics:Research Funding;AI Therapeutics:Research Funding;Trillium:Research Funding;Affimed:Research Funding;Regeneron:Research Funding;Seattle Genetics:Research Funding;Bristol Myers Squibb:Research Funding;Takeda:Research Funding.Witzig:Spectrum:Consultancy;Celgene:Consultancy, Research Funding;Immune Design:Research Funding;Karyopharm Therapeutics:Research Funding;Acerta:Research Funding;Incyte:Consultancy;AbbVie:Consultancy;MorphSys:Consultancy.