Efficacy of the BNT162b2 mRNA COVID-19 Vaccine in Patients with Chronic Lymphocytic Leukemia: A Serologic and Cellular Study

Background: Antibody response following SARS-CoV2 vaccination is somewhat defective in chronic lymphocytic leukemia (CLL). Moreover, the correlation between serologic response and status of cellular immunity has been poorly studied. Objective: This study was undertaken to assess humoral immune and cellular responses to the BNT162b2 messenger RNA (mRNA) COVID-19 vaccination in CLL. Methods: The presence of the spike antibodies was assessed at a median time of 14 days from the second vaccine dose of SARS-CoV2 in 70 CLL followed-up at a single institution. Results: The antibody response rate (RR) in CLL patients was 58.5%, compared to 100% of 57 healthy controls of the same sex and age (P< 0.0001). Patients treatment-naïve and those in sustained clinical remission after therapy had the highest RR (87.0% and 87.7%, respectively). In contrast, patients on therapy with a pathway inhibitor as monotherapy and those treated with an association of anti-CD20 antibody were unlikely to respond to the SARS-CoV-2 vaccine (52% and 10%, respectively). In multivariate analysis, early Rai stage (OR, 0.19 [0.05-0.79]; P=0.02) and no previous therapy (OR, 0.06[0.02-0.27]; P<0.0001) were found to be independent predictors of vaccination response. An increase in absolute NK cells (i.e., CD16/CD56 positive cells) in patients with a serological response was found following the second dose of vaccine (P=0.02). Conclusions: These results confirm that serological response to the BNT162b2 vaccine in patients with CLL is impaired. A third boosting vaccine dosage should be considered for these patients.

Serum sickness reaction to obinutuzumab in a patient with chronic lymphocytic leukaemia

Serum sickness (SS) is a known phenomenon; however, it is commonly missed due to vague symptoms, and is usually confounded by other aetiologies that present similarly. Obinutuzumab is a novel anti-CD20 antibody agent that has been approved for chronic lymphocytic leukaemia (CLL) treatment. At the time of approval, it was not linked to SS; however, this phenomenon has been recognised with other anti-CD20 agents like rituximab. SS remains a rare entity, but it is important to be recognised accurately and quickly in the appropriate circumstances, so that effective treatment with corticosteroids can be initiated to alleviate inflammatory symptoms. Here we present a patient with CLL who developed maculopapular rash, fever and polyarthritis and elevated inflammatory markers consistent with serum sickness triggered by obinutuzumab and was effectively treated with corticosteroids.

Increase in Antibody Titers Following Sars-Cov-2 Vaccination Remains Limited for More Than 3 Years after Final Dose of Anti-CD20 Antibody

COVID-19, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has become a global pandemic. Patients with hematological disorders are known to be at high risk of morbidity and mortality from COVID-19, and vaccines against SARS-CoV-2 have been rapidly developed. Although mRNA vaccines against SARS-CoV-2 are reported to be effective, efficacy in patients with hematological malignancies who have received anti-CD20 antibody treatment remains unclear. Here, we prospectively evaluated the efficacy of BNT162b2 mRNA COVID-19 vaccine in patients with B-cell malignancies treated with anti-CD20 antibody. We first evaluated antibody titers in 12 healthy volunteers (median age 75.5 years, range 57-82) and three lymphoma patients undergoing R-CHOP therapy (73, 81, and 81 years old) who had received 2 vaccine doses of BNT162b2 at pre-vaccination, 21 days after the first dose and 14 days after the second dose of vaccination. IgG antibody titers for S1 protein were measured in serum samples by ELISA. In healthy control subjects, titers were clearly increased. In contrast, no patient treated with R-CHOP developed antibodies even after the second vaccination (Figure A). To determine the SARS-CoV-2-specific T-cell reactivity in these three patients, we evaluated interferon (IFN)-γ response to the SARS-CoV-2 spike peptide before and after the second vaccination dose, and detected IFN-γ responses after vaccination in all three patients (Figure B). Next, to investigate the duration of the effect of anti-CD20 antibody on antibody production to BNT162b2, we enrolled 36 patients (median age 74 years, range 50-87) who had received the final dose of anti-CD20 antibody 48-1320 (median 571) days before vaccination. S1 antibody titers were measured 14 days after the second dose of vaccination. Diagnoses included diffuse large B-cell lymphoma (n = 21), follicular lymphoma (n = 9), lymphoplasmacytic lymphoma/Waldenström's macroglobulinemia (n = 3), and mantle cell lymphoma (n = 3). Thirty-four patients had received rituximab-based and 2 had received obinutuzumab-based therapy, with a median of 6 (range 3-20) courses. No patient had received any chemotherapy after the last anti-CD20 antibody dose. No patient vaccinated within close to one year or sooner after the last anti-CD20 antibody administration showed an increase in titers. Furthermore, titers in most patients were lower than in healthy volunteers even among those vaccinated more than three years after the last administration (Figure C). Finally, we investigated surrogate markers of antibody production ability. We found no relationship between the percent of B-cells (CD19-positive cells) and S1 antibody titers (Figure D), whereas all patients (n = 9) with total IgG level below lower normal limit (&lt; 870 mg/dl) had low S1 antibody titers (&lt; 0.16), below the lowest optical density (O.D.) value in healthy donors (Figure E). These findings indicate that the antibody-mediated response to vaccination in patients following treatment with anti-CD20 antibody was considerably impaired for an extended time. Alternative protection strategies for these patients are therefore warranted. Although T-cell responses were detected, we recommend that these patients continue to wear a face mask and wash their hands to prevent COVID-19 even after vaccination. Figure 1 Figure 1. Disclosures Yakushijin: Chugai pharmaceutical Co. Ltd.: Research Funding; Jazz pharmaceuticals: Research Funding; Nippon Shinyaku: Honoraria. Kiyota: Bristol-Myers Squibb: Honoraria, Research Funding; Ono Pharmaceutical: Honoraria, Research Funding; Astra-Zeneca: Honoraria, Research Funding; Roche Phamaceuticals: Research Funding; Merck Biopharma: Honoraria; Merck Sharp & Dohme: Honoraria; Eisai: Honoraria; Bayer: Honoraria. Matsuoka: Takeda Pharmaceutical Company: Research Funding; Sysmex: Research Funding. Minami: Behring: Research Funding; CSL: Research Funding; Yakult Honsha: Research Funding; Nippon Shinyaku: Research Funding; Astellas Pharma: Research Funding; Asahi-Kasei Pharma: Research Funding; Eli Lilly: Honoraria, Research Funding; Taiho Pharmaceutical: Honoraria, Research Funding; Takeda Pharmaceutical: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Ono Pharmaceutical: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; MSD: Honoraria, Research Funding; Merck Serono: Honoraria, Research Funding; Kyowa-Kirin: Honoraria, Research Funding; Eisai: Honoraria, Research Funding; DaiichiSankyo: Honoraria, Research Funding; Chugai Pharmaceutical: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Boehringer Ingelheim: Honoraria, Research Funding; Bayer Yakuhin: Honoraria, Research Funding; Nippon Kayaku: Research Funding; Celgene: Honoraria; Ohtsuka Pharmaceutical: Honoraria; Shire Japan: Honoraria; Genomic Health: Honoraria; Abbvie: Honoraria.

A Clue to Better Select Chronic Lymphocytic Leukemia Patients with Optimal Response to BNT162b2 mRNA COVID-19 Vaccine

Given the immunosuppression of chronic lymphocytic leukemia (CLL), this disease represents a challenging model for assessing the extent of serologic response to mRNA vaccination against severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). In this perspective, we assessed the efficacy of the BNT162b2 mRNA COVID-19 vaccine in 70 CLL pts followed up at single hematological institution. The study was approved by the Institutional Review Board. Serologic testing for SARS Cov2 IgG was performed using the LIAISON® SARS-CoV-2 S1/S2 IgG test (DiaSorin; Saluggia, Italy), a chemiluminescence immunoassay for the quantitative determination of anti-S1 and anti-S2 specific IgG antibodies to SARS-CoV-2. Clinical sensitivity and specificity of assay were 98.7% and 99.5% respectively. Samples were considered negative for antibody titers below 13 AU/ml. Results were compared with those of an age-matched group of subjects with no hematological malignancy (n=57). Patient samples for serology testing were obtained after median time of 14 days (range, 14-28) from the second vaccine dose. Median age of CLL pts was 72 years (range, 63-88) and 71.4% were males. The median time from CLL diagnosis to vaccination was 82.5 mo. (range, 1-280). Twenty-three pts (32.9%) were treatment naïve (TN), 36 (51.4%) on active therapy (i.e., BTKi, 22; anti-BCL2 12; PI3Ki,1; cyclophosphamide,1) and 11 (15.7%) off-therapy (i.e., 8 in complete [CR] or partial remission [PR], and 3 in CLL relapse). Of note, 9 (25.7%) of 35 pts on therapy with a pathway inhibitor (PI) at the time of vaccination had been given an anti-CD20 antibody. The vaccine elicited an antibody-mediated response in 41 (58.5%) of the 70 CLL pts. An inferior response rate [RR] (58.5% vs 100%, OR, 0.012 [0.0007-0.206];P=0.02) and a lower antibody titers (median, 58 AU/ml; range, 1.8-800 vs. 284 AU/ml; range, 14-800; P&lt; 0.0001) were observed in CLL pts in comparison to age-matched subjects with no hematological malignancy. The RR was higher in TN (87%) or off-therapy pts with sustained clinical response (87.5%) in comparison to pts on therapy at the time of vaccination (41.7%)(&lt;0.0001). Similar results were observed when comparison was performed in terms of antibody titers (P=0.02;Kruskall-Wallis test; Fig 1). In comparison to pts treated with a PI as monotherapy, those who received an anti-CD20 antibody in association to PI had a lower antibody response to SARS-CoV-2 vaccine (11.1% vs 53.8%; OR,0.107 [0.011-0.984];P=0.04). In univariate analysis, the following variables were significantly associated with serological response to SARS-CoV-2 vaccination: early Rai stage (i.e.,0-I) (OR, 0.36 [0.13-0.97];P=0.04), mutated IGHV status (OR,0.30 [0.10-0.88]; P=0.02), lack of active therapy - which comprised TN and off-therapy pts with sustained response - (OR,0.09 [0.03-0.32];P&lt;0.0001), and no anti-CD20 antibody exposure preceding vaccination (OR, 013 [0.01-1.23];P=0.04). Levels of immunoglobulins or absolute values of CD3,CD4,CD8, and CD16/CD56 cells measured before the first COVID-19 vaccination were not associated to vaccine response. Of note, in pts who experienced a serological response a concomitant increase of the absolute of CD16/CD56 positive cells was observed (P=0.02). Finally, Rai stage (OR, 0.19 [0.05-0.79]; P=0.02) and treatment status (OR, 0.06 [0.02-0.27]; P&lt;0.0001) were independent predictors of response in multivariate analysis. We used these factors to build a score that identified pts with different pattern of response to vaccine. Serologic response to SARS-CoV-2 vaccination was 100% in pts with no factor (n=21), 45% in pts. with one factor (n=38) and 36% in pts with two factors (n=11) (P&lt;0.0001). In agreement with results of recent studies (Herishanu et al, Blood 2021; Roeker et al, Leukemia 2021;Perry et al, Blood Cancer J. 2021; Benjamini O et al, Haematologica 2021 ) our findings suggest that antibody-mediated response to COVID-19 vaccination is significantly reduced in CLL and influenced by disease activity and treatment status. The serological response to SARS-CoV-2 vaccination observed in pts. with early disease with no need of therapy may help to identify CLL pts who are expected to achieve an optimal response to COVID-19 vaccine similarly to age- and sex-matched controls. Figure 1 Figure 1. Disclosures Molica: Astrazeneca: Honoraria; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria.

CD20-Specific Chimeric Antigen Receptor-Expressing T Cells As Salvage Therapy in Rituximab-Refractory CD20(+) B-Cell Non-Hodgkin Lymphoma

Background: CD20 antibody-based chemotherapy has been verified as a valid strategy and prolonged the overall survival (OS) of CD20(+) B-cell Non-Hodgkin Lymphoma (B-NHL) patients. However, over 40% of these patients finally would be relapsed or refractory(R/R) to CD20 antibody rituximab. Treatment of these R/R B-NHL patients has not been standardized yet. Furthermore, it is still a question that whether CD20-specific CAR T-cells could provide an alternative therapy in rituximab-relapsed/refractory B-NHL patients. Methods: Here, we conducted a prospective single-center study on patients with relapsed/refractory to CD20 antibody(No.ChiCTR2000036350). The aim of this study aims was to evaluate the efficacy and in vivo persistence of CART-20 cells in subjects with rituximab R/R CD20(+) B-NHL patients. Between October 2017 to December 2020, 15 patients with R/R B-NHL patients (including 14 DLBCL patents and 1 MCL patient) received anti-CD20 specific CAR T cell therapy. The efficacy of CAR T-cells therapy was evaluated at different assessment points by CT scan or 18FDG-PET. CAR-T expansion in blood was monitored regularly by real-time quantitative PCR (qPCR). Results: In this study, the clinical characteristic of these enrolled patients was a median age at 48 years (range 30 to 66), male n=7(47%). 10 (67%) patients were relapsed and 5 patients (33%) were refractory to rituximab-based chemotherapy.(Table 1) All of these patients were at advanced stage III/IV and 7 (47%) of them were diagnosed with bulky disease. The median time from latest rituximab utilization is 70 days (rang 31-471 days) before CAR T-20 cells infusion. The median number of lines of previous treatments was 4 (2-8). 14 patients (93%) received CAR T-20 with a dose of 1*10^7/kg, the median follow-up time for patients was 219 days (32 to 1231). CRS (100%) was observed in all 15 infusion patients: 11 patients grade I-II and 4 patients' grade ≥III. ICANS was recorded only in 1 patient (grade I). At 30 days after the infusion, the clinical response of all 15 infusion patients could be assessed: 4 (27%) CR, 11 (73%) PR, and ORR 100%.(Figure 1) 5 patients who were in PR at 30 days converted to CR, with a median time of 116 (6-858), and continued follow-up without relapse; 6 patients (40%) had relapse, with a median relapse time of 136 days (48- 1050), this might be related to the short time of rituximab before the CAR-T infusion.Although the cases are limited, we can still draw a preliminary conclusion that the use of rituximab within three months may not affect the efficacy of CD20-CAR-T, but may lead to early recurrence. Furthermore, the persistence time of CART-20 cells were comparably longer than that CART-19 cell infusions. Conclusions: In conclusion，these findings suggest that the use of CAR T-20 can be served as a salvage therapy in Rituximab-refractory CD20(+) B-cell Non-Hodgkin Lymphoma and raises the possibility of using CAR T-20 in an early disease stage. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Estimating treatment effect for individuals with progressive multiple sclerosis using deep learning

Modeling treatment effect could identify a subgroup of individuals who experience greater benefit from disease modifying therapy, allowing for predictive enrichment to increase the power of future clinical trials. We use deep learning to estimate the conditional average treatment effect for individuals taking disease modifying therapies for multiple sclerosis, using their baseline clinical and imaging characteristics. Data were obtained as part of three placebo-controlled randomized clinical trials: ORATORIO, OLYMPUS and ARPEGGIO, investigating the efficacy of ocrelizumab, rituximab and laquinimod, respectively. A shuffled mix of participants having received ocrelizumab or rituximab, anti-CD20-antibodies, was separated into a training (70%) and testing (30%) dataset, but we also performed nested cross-validation to improve the generalization error estimate. Data from ARPEGGIO served as additional external validation. An ensemble of multitask multilayer perceptrons was trained to predict the rate of disability progression on both active treatment and placebo to estimate the conditional average treatment effect. The model was able to separate responders and non-responders across a range of predicted effect sizes. Notably, the average treatment effect for the anti-CD20-antibody test set during nested cross-validation was significantly greater when selecting the model's prediction for the top 50% (HR 0.625, p=0.008) or the top 25% (HR 0.521, p=0.013) most responsive individuals, compared to HR 0.835 (p=0.154) for the entire group. The model trained on the anti-CD20-antibody dataset could also identify responders to laquinimod, finding a significant treatment effect in the top 30% of individuals (HR 0.352, p=0.043). We observed enrichment across a broad range of baseline features in the responder subgroups: younger, more men, shorter disease duration, higher disability scores, and more lesional activity. By simulating a 1-year study where only the 50% predicted to be most responsive are randomized, we could achieve 80% power to detect a significant difference with 6 times less participants than a clinical trial without enrichment. Subgroups of individuals with primary progressive multiple sclerosis who respond favourably to disease modifying therapies can therefore be identified based on their baseline characteristics, even when no significant treatment effect can be found at the whole-group level. The approach allows for predictive enrichment of future clinical trials, as well as personalized treatment selection in the clinic.

266 AK117, a CD47 blocking antibody with robust macrophage activation without red blood cell hemagglutination

BackgroundAK117 is a humanized monoclonal antibody targeting CD47 which widely expresses on innate immune cells, such as macrophages, and functions as a regulator of phagocytosis. CD47 serves as the ligand for a receptor on these innate immune cells, SIRPα, which in turn delivers an inhibitory signal for phagocytosis. Hematology toxicity is the major concern of an anti-CD47 antibody. As an agent targeting CD47 being investigated as an anti-tumor therapeutic, AK117 is engineered on a human IgG4 scaffold to minimize recruitment of Fc-dependent effector functions, as well as identified with favorable hematology safety profile and robust pro-phagocytosis activity.MethodsActivity of AK117 binding to CD47 to block the interaction between CD47 and SIRPα were determined by FACS, and binding of AK117 to human RBC was also evaluated. Raji cells, HT-29 cells, and HL-60 cells which highly express CD47 were used as target cells to evaluate a pro-phagocytic activity of AK117 as a monotherapy or in combination with anti-EGFR antibody, anti-CD20 antibody or azacitidine. In in-vivo pharmacology studies, anti-tumor activity of AK117 was investigated in SCID/beige mouse Raji tumor model. Effects of AK117 on hemagglutination of human RBC at was tested. Hemoglobin (HGB) and hematocrit (HCT) was evaluated after single dose of 10 mg/kg AK117 or Hu-5F9 in male and female cynomolgus monkeys (n=1/gender).ResultsAK117 could effectively binds to CD47, and competes with SIRPα for binding to the antigen on Raji cells (figure 1). AK117 alone or combines with anti-EGFR antibody, anti-CD20 antibody and azacitidine shows potent phagocytosis of tumor cells in a dose-dependent manner (figure 2). AK117 significantly inhibited tumor growth in these tumor models (figure 3). Favorable hematology safety profile of AK117 was observed. A significant weaker binding to human RBC of AK117 was identified (figure 4), and AK117 does not induce hemagglutination of human RBC up to a concentration of 1050 μg/mL, while Hu-5F9 triggers hemagglutination even at a low concentration of 1.44 μg/mL (figure 5). AK117 has minimal anemia effect in monkey studies compared to hu5F9-G4 after single dose in cynomolgus monkeys (figure 6). AK117 showed a rather superior safety profile to Hu5F9-G4 as a shorter duration of anemia.Abstract 266 Figure 1Binding and Competition activity of AK117 to CD47. (A) FACS binding curves of AK117 and Hu5F9-G4 to CD47 on raji cells. (B) FACS competitive binding curve of AK117 and Hu5F9-G4 with SIRPαECD-mFc to CD47 on raji cells.Abstract 266 Figure 2The pro-phagocytic activity against tumor cells. (A) The phagocytic index of raji cells by macrophages with AK117. (B) The phagocytic index of HL-60 cells by macrophages with AK117 and azacitidine. (C) The phagocytic index of HT-29 cells by macrophages with AK117 and cetuximab. (D) The phagocytic index of raji cells by macrophages with AK117 and rituximab.Abstract 266 Figure 3Anti-tumor activity in raji tumor mouse model. The (A) Tumor growth curves and (B) Body weight curves of different groups in SCID/Beige mice with subcutaneous raji tumor.Abstract 266 Figure 4Binding activity of AK117 to human RBCs. Binding Curves of Hu5F9-G4 and AK117 to CD47 on human RBCsAbstract 266 Figure 5Hemagglutination effect on human erythrocytes. Hemagglutination effect of AK117 on human erythrocytesAbstract 266 Figure 6HGB and HCT in cynomolgus monkeys. The curves of (A) hemoglobin and (B) Hematocrit at different times in cynomolgus monkeys.ConclusionsWith pre-clinical pharmacology activities comparable to Hu5F9-G4 as well as superior safety properties demonstrated in non-clinical pharmacodynamics studies, AK117 has emerged as a promising new treatment for solid tumor.

Successful Treatment of Persistent SARS-CoV-2 Infection in a B-Cell Depleted Patient with Activated Cytotoxic T and NK Cells: A Case Report

We report a lymphoma patient with profound B-cell deficiency after chemotherapy combined with anti-CD20 antibody successfully treated with remdesivir and convalescent plasma for prolonged SARS-CoV-2 infection. Viral clearance was likely attributed to the robust expansion and activation of TCR Vβ2 CD8+ cytotoxic T cells and CD16 + CD56- NK cells. This is the first presentation of TCR-specific T cell oligoclonal response in COVID-19. Our study suggests that B-cell depleted patients may effectively respond to anti-SARS-CoV-2 treatment when NK and antigen-specific Tc cell response is induced.

Follicular Lymphoma and Macrophages: Impact of Approved and Novel Therapies

The survival and proliferation of follicular lymphoma (FL) cells is strongly dependent on macrophages, their presence being necessary for the propagation of FL cells in vitro. To this regard, as shown also for the majority of solid tumors, a high tissue content of tumor-associated macrophages (TAMs), particularly if showing a pro-tumoral phenotype (also called M2) has strongly associated with a poor outcome among FL patients treated with chemotherapy. The introduction of rituximab, an anti-CD20 antibody which can be used by TAMs to performed antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis, has challenged this paradigm. In the rituximab-era, in fact, clinical studies have yielded conflicting results in FL, showing variable outcomes based on the type of employed regimen. This has highlighted for the first time that the impact of TAM on the prognosis of FL patients may depend on the administered treatment, emphasizing the need to better understand how currently available therapies affect macrophage function in FL. We summarize here the impact of approved and novel therapies for FL on the biology of TAMs, including radiation therapy, chemotherapy, anti-CD20 monoclonal antibodies, lenalidomide, and targeted agents, and describe their effects on macrophage phagocytosis, polarization and function. While novel agents targeting the CD47/SIRPα axis are being developed and showing promising activity in FL, a deeper understanding of macrophage biology and their complex pathways will help to develop novel and safer therapeutic strategies for patients with this type of lymphoma.