Humoral Response to mRNA Vaccines BNT162b2 and mRNA-1273 COVID-19 in Chronic Lymphocytic Leukemia Patients

• Published in: Blood 2021-11, Vol.138 (Supplement 1), p.637-637
• Main Authors: Bagacean, Cristina, Letestu, Rémi, Al Nawakil, Chadi, Brichler, Ségolène, Lévy, Vincent, Sritharan, Nanthara, Delmer, Alain, Dartigeas, Caroline, Leblond, Véronique, Roos-Weil, Damien, Béné, Marie C, Clavert, Aline, Chaoui, Driss, Genet, Philippe, Guieze, Romain, Laribi, Kamel, Touileb, Yamina, Drenou, Bernard, Willems, Lise, Tomowiak, Cécile, Merabet, Fatiha, Puppink, Christian, Legendre, Hugo, Troussard, Xavier, Malartre, Stéphanie, Cymbalista, Florence, Michallet, Anne-Sophie
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2021-152515

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for an ongoing global pandemic. Phase III trials have demonstrated excellent efficacies of mRNA vaccines against SARS-CoV-2 in large population studies (Baden LR, NEJM, 2021; Polack FP, NEJM, 2020). Immunosuppressed individuals such as chronic lymphocytic leukemia (CLL) patients are at risk for a suboptimal response to 2 vaccine doses (Herishanu Y, Blood, 2021). The French National Authority for Health recommends the use of a third dose in immunosuppressed patients. However, seroconversion rate after the triple-dose vaccine is not yet known. The objective of our study was to evaluate SARS-CoV-2 antibody responses after the first, second and third doses of the BNT162b2 and mRNA-1273 vaccines. Data were collected from 17 French Innovative Leukemia Organization (FILO) investigating centers and the French CLL patients' association (SILLC). SARS-CoV-2 IgG anti-Spike levels were measured at 4-6 weeks after each vaccine dose. A total of 530 patients and 14 controls were included in the study. Vaccine response was evaluated post-dose 1 for 158 CLL patients, post-dose 2, for 506 patients and post-dose 3 for 66 patients. Peripheral blood lymphocyte subsets were studied post-dose 2 by flow cytometry in 80 CLL patients and 14 controls. The median age of the patients was 71 years (range 37-93), 218 (40%) were treatment-naïve (TN), 136 (26%) had a prior CLL treatment and 176 (34%) were on therapy. Post-dose 1, the global response rate was 27% (43/158). TN patients had a response rate of 34% (23/67), similar to those who had a prior CLL treatment (33%,12/36), and higher compared to on-therapy patients (15%, 8/55, P=0.02). Post-dose 2, the global response rate was 52% (265/506). TN patients had the highest response rate of 72% (151/210) compared to previously treated patients, mostly by immunochemotherapy (60%, 78/130, P=0.02) and on-therapy patients (22%, 36/166, P