ABSTRACT
Background: Patients with chronic lymphocytic leukemia (CLL) show high infection-related morbidity and mortality due to variable degree of humoral and cellular immune deficiency. High Covid-related mortality and reduced response to the SARS-Cov-2 vaccine have been reported in this patient population. Aims: We carried out a prospective multicenter study to define the rate of CLL patients with an appropriate immune response after the mRNA SARS-CoV2 vaccine (Pfizer-BioNTech;Moderna). Methods: Two-hundred patients with CLL received the first dose of the SARS-CoV-2 vaccine between February and August 2021. Centralized assessment of the anti-SARS-Cov-2 IgG levels (Sero Index, Kantaro Quantitative SARS-CoV-2 IgG Antibody, RUO-R&D System) was performed at the Istituto Superiore di Sanità of Rome, Italy. The median followup of this study is 10.7 months (range 1-12.9). Results: The median age of patients was 70 years, the median IgG level was 635 mg/dl, 61% of patients were IGHV unmutated, and 34% showed TP53 disruption. The majority of patients, 83.5%, were previously treated. Prior treatment included chemoimmunotherapy in 20 (10%) patients, ibrutinib-based therapy in 72 (36%;front-line, 21%;advanced line, 15%), venetoclax-based therapy in 75 (37.5%;front-line, 13.5%;advanced line, 24%). Overall, 135 (77.5%) patients had been previously treated with rituximab, 33 (16.5%) of them within 12 months before vaccination. We assessed the serologic response after the second dose of the SARS-CoV2 vaccine in 195 patients while five were excluded from the analysis (positive test before vaccination, 3 patients;lost to the follow-up, 1;Richter syndrome, 1). Adequate levels of anti-SARS-Cov-2 IgG were detected in 76/195 (39%) patients. Age (<70 vs.≥ 70 years;p <0.0001), CIRS value (<6 vs. ≥6;p=0.005), beta-2 microglobulin (<3.5 vs. ≥ 3.5mg/dl;p=0.04), IgG levels (<550 vs. ≤ 550 mg/dl;p <0.0001), prior treatment (p=0.0001), number of prior treatments (0+1 vs. ≥ 2;p=0.002) and the time between prior rituximab and vaccination (>12 vs. ≤12 month;p=0.001) showed a significant impact on the humoral response. In multivariate analysis only age (OR: 0.92 [95% CI: 0.92-0.97] p=0.0001), IgG levels (OR: 0.28 [95% CI: 0.13-0.58] p<0.001), and the time between prior rituximab and vaccination (OR: 0.10 [95% CI: 0.03-0.37] p=0.001), revealed a significant and independent impact on response. When the analysis was restricted to patients who received targeted therapy, in addition to the younger age (OR: 0.96 [95% CI: 0.92-0.99] p=0.04), higher IgG levels at baseline (OR: 0.31 [95% CI: 0.12-0.79] p=0.014), longer time between the start of ibrutinib or venetoclax-based therapy and vaccination (<18 vs.≥18 months;OR: 0.17 [95% CI: 0.06-0.44], p <0.0001) showed a favorable and independent impact on response. Ninety-three% (182/195) of patients received a third dose of the vaccine. A significant increase in the rate of serologic responses, 51.5% (85/165 evaluated patients, p=0.019), was observed after the booster dose. Moreover, a response was detected in 25% (26/103 evaluated patients) of previously seronegative patients. Summary/Conclusion: In this prospective, multicenter, centralized study, we recorded an effective immune response to the SARS-CoV-2 vaccine in about a third of patients with CLL. Younger age, higher IgG levels, no prior treatment, or stable disease after targeted therapy that suggest preserved immunocompetence were associated with a greater likelihood of achieving an effective immune response. A booster dose of the SARS-CoV-2 vaccine proved beneficial also in previously seronegative patients.
ABSTRACT
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< 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%)(<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<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<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<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 v ccination 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. [Formula presented] Disclosures: Molica: Astrazeneca: Honoraria;Abbvie: Consultancy, Honoraria;Janssen: Consultancy, Honoraria.