Patients with chronic lymphocytic leukemia (CLL) have an increased risk for severe COVID-19 disease and mortality. The goal of this study (NCT04746092) was to determine the efficacy of COVID-19 vaccine in patients with CLL. We evaluated humoral immune responses to BNT162b2 mRNA COVID-19 vaccine in patients with CLL and compared responses with those obtained in age-matched healthy controls. Patients received two vaccine doses, 21 days apart, and antibody titers were measured using Elecsys® Anti-SARS-CoV-2S assay after administration of the second dose. In a total of 167 patients with CLL the antibody response rate was 39.5%. A comparison between 52 patients with CLL and 52 sex- and aged-matched healthy controls, revealed a significantly reduced response rate among patients (52% vs 100%, respectively; adjusted odds ratio=0.010, 95% CI 0.001-0.162; p<0.001). Response rate was highest in patients who obtained clinical remission after treatment (79.2%), followed by 55.2% in treatment-naïve and 16% only in patients under treatment at the time of vaccination. In patients treated with either BTK inhibitors or venetoclax ± anti-CD20 antibody, response rates were considerably low (16.0% and 13.6%, respectively). None of the patients exposed to anti-CD20 antibodies <12 months prior to vaccination responded. In a multivariate analysis, the independent predictors of response were younger age, females, lack of currently active treatment, IgG levels ≥550 mg/dL and IgM levels ≥40mg/dL. In conclusion, antibody-mediated response to BNT162b2 mRNA COVID-19 vaccine in patients with CLL is markedly impaired and affected by disease activity and treatment.

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Chronic lymphocytic leukemia (CLL) is a disease of the elderly, characterized by immunodeficiency. Hence, patients with CLL might be considered more susceptible to severe complications from COVID-19. We undertook this retrospective international multicenter study to characterize the course of COVID-19 in patients with CLL and identify potential predictors of outcome. Of 190 patients with CLL and confirmed COVID-19 diagnosed between 28/03/2020 and 22/05/2020, 151 (79%) presented with severe COVID-19 (need of oxygen and/or intensive care admission). Severe COVID-19 was associated with more advanced age (≥65 years) (odds ratio 3.72 [95% CI 1.79-7.71]). Only 60 patients (39.7%) with severe COVID-19 were receiving or had recent (≤12 months) treatment for CLL at the time of COVID-19 versus 30/39 (76.9%) patients with mild disease. Hospitalization rate for severe COVID-19 was lower (p < 0.05) for patients on ibrutinib versus those on other regimens or off treatment. Of 151 patients with severe disease, 55 (36.4%) succumbed versus only 1/38 (2.6%) with mild disease; age and comorbidities did not impact on mortality. In CLL, (1) COVID-19 severity increases with age; (2) antileukemic treatment (particularly BTK inhibitors) appears to exert a protective effect; (3) age and comorbidities did not impact on mortality, alluding to a relevant role of CLL and immunodeficiency.

Multiple myeloma (MM) patients are at excess risk for clinically significant COVID19 infection. BNT162b2 mRNA COVID19 (BNT162b2) vaccine provides effective protection against COVID19 for the general population, yet its effect in MM patients may be compromised due to disease and therapy-related factors and was not yet evaluated. This single-centre prospective study included MM patients tested for serological response 14-21 days post second vaccine. Vaccinated healthy volunteers served as controls. In all, 171 MM patients, median age 70 (38-94) were included; 159 active MM and 12 smouldering myeloma (SMM). Seropositive response rate (median titer) was 76% (91 U/ml) in active MM patients vs 98% (992 U/ml) in the 64 controls (P < 0Á0001), and 100% (822 U/ml) in SMM patients. Multivariate analysis revealed older age (P = 0Á009), exposure to ≥4 novel anti-myeloma drugs (P = 0Á02) and hypogammaglobulinaemia (P = 0Á002) were associated with lower response rates. None of the novel agents significantly decreased response rate, whereas daratumumab trended towards reduced response (P = 0Á08). Adverse events occurred in 53% and 55% of the MM patients and controls, respectively, all transient grade 1-2. In conclusion, BNT162b2 vaccine was safe and provided a high seropositivity rate in MM patients, independent of treatment type. Older, hypogammaglobulinaemic and heavily pretreated patients had lower response rates.

TO THE EDITOR Bruton tyrosine kinase (BTK) inhibitors have improved chronic lymphocytic leukemia (CLL) outcomes and offer a chemotherapyfree option [1]. The BTK inhibitor ibrutinib, alone or with a CD20 antibody, demonstrated better efficacy versus chemoimmunotherapy in treatment-naïve (TN) CLL [2][3][4]. However, cardiovascular toxicity is a concern with continuous ibrutinib use [5,6].Acalabrutinib is a next-generation, selective BTK inhibitor approved for CLL/small lymphocytic leukemia (SLL). Acalabrutinib, alone or with obinutuzumab, showed favorable efficacy in clinical trials [7,8]. ELEVATE-TN demonstrated superior efficacy for acalabrutinib-obinutuzumab versus obinutuzumab-chlorambucil with acceptable tolerability in TN CLL [9]. We report 4-year followup results from ELEVATE-TN.ELEVATE-TN is a phase 3, randomized, multicenter, open-label study (NCT02475681) that enrolled patients aged ≥65 years, or 18-65 years with comorbidities (Cumulative Illness Rating Scale-Geriatric score >6, creatinine clearance 30-69 mL/min by Cockcroft-Gault), who had TN CLL or SLL requiring treatment, Eastern Cooperative Oncology Group performance status score of ≤2, and adequate hematologic, hepatic, and renal function [9]. Patients were randomized (1:1:1) to acalabrutinib 100 mg twice daily (until disease progression or unacceptable toxicity) with or without obinutuzumab (fixed-duration, up to 6 cycles) or obinutuzumab plus chlorambucil (up to 6 cycles). Crossover to acalabrutinib monotherapy was permitted in patients who progressed on obinutuzumab-chlorambucil. The primary study endpoint was independent review committee (IRC)-assessed progression-free survival (PFS). After primary analysis, PFS was investigatorassessed.Key secondary/exploratory endpoints were investigator-assessed PFS, investigator-assessed overall response rate (ORR), overall survival (OS), undetectable minimal residual disease (uMRD) rate, and safety. The study was not powered to compare acalabrutinib versus acalabrutinib-obinutuzumab. Informed consent was obtained from all patients before enrollment. Study details were previously published [9].In total, 535 patients were randomized (acalabrutinib-obinutuzumab, n = 179; acalabrutinib, n = 179; obinutuzumab-chlorambucil, n = 177). Median age was 70 years (range, 41.0-91.0); 14% had del(17)(p13.1) and/or mutated TP53 and 63% had unmutated immunoglobulin heavy chain variable (IGHV) gene (Supplementary Table 1).At a median follow-up of 46.9 months (range, 0.0-59.4), treatment was ongoing in 74.9% (n = 134) and 69.3% (n = 124) of patients in the acalabrutinib-obinutuzumab and acalabrutinib monotherapy arms, respectively (Supplementary Table 2). Sixty-

An insect-bite-like reaction is known to occur in patients with chronic lymphocytic leukemia (CLL). Most of the literature, however, consists of isolated case reports or small case series. The aim of this retrospective study was to review the national experience with insect-bite-like reaction in a large group of patients with CLL. The study cohort of patients with these skin reactions consisted of 48 patients (25 males, 23 females) of mean age 64.8 yr (range 33-89) at skin eruption. Data on clinical, histologic, immunophenotypic, and cytogenetic characteristics, treatment, and outcome were collected from the medical files. Mean time between diagnosis of CLL and appearance of the skin lesions was 3.1 yr (range -4 to 14 yr). The eruption was not related to disease activity or the course of the hematological disease. The eruption preceded the diagnosis of CLL in 10 patients (by 0-4 yr); and followed the diagnosis in 36; in 11 patients, it occurred during therapy for CLL and in nine after therapy. Mean duration of the skin findings was 21.5 months (range 0.3-132). The eruption usually presented in summer, although it occurred also at other times of the year, and predominantly affected the upper and lower limbs, although it also appeared on unexposed areas. Treatment included local ointments, antihistaminics, oral steroids, antibiotics, phototherapy, and dapsone with varying responses. Insect-bite-like reactions is a relatively common and disturbing skin reaction in CLL patients, it may be related to the immune dysregulation accompanying CLL and further exacerbated by external factors, including actual insect bites, chemoimmunotherapy, and pyogenic infection.

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Lasting B-cell persistence depends on survival signals that are transduced by cell surface receptors. Here, we describe a novel biological mechanism essential for survival and homeostasis of normal peripheral mature B cells and chronic lymphocytic leukemia (CLL) cells, regulated by the heparin-binding cytokine, midkine (MK), and its proteoglycan receptor, the receptor-type tyrosine phosphatase zeta (RPTPζ). We demonstrate that MK initiates a signaling cascade leading to B cell survival, by binding to RPTPζ. In mice lacking PTPRZ, the proportion and number of the mature B cell population is reduced. Our results emphasize a unique and critical function for MK signaling in the previously described MIF/CD74 induced survival pathway. Stimulation of CD74 with MIF leads to c-Met activation, resulting in elevation of MK expression in both normal mouse splenic B and CLL cells. Our results indicate that MK and RPTPζ are important regulators of the B cell repertoire. These findings could pave the way towards understanding the mechanisms shaping B cell survival, and suggest novel therapeutic strategies based on the blockade of the midkine/RPTPζ-dependent survival pathway.