Chronic graft vs. host disease and hypogammaglobulinemia predict a lower immunological response to the BNT162b2 mRNA COVID-19 vaccine after allogeneic hematopoietic stem cell transplantation.

OBJECTIVE: Due to the high mortality rate of COVID-19, the assessment of BNT162b2 SARS-CoV-2 mRNA vaccine (Pfizer-BioNTech) efficacy in allogeneic hematopoietic stem cell transplant (HSCT) recipients is mandatory. PATIENTS AND METHODS: We conducted a single-center pilot study with the main objective of evaluating the immunogenicity of the BNT162b2 mRNA vaccine in 31 hematological patients who underwent hematopoietic stem cell transplantation within the previous 12 months and/or were affected by chronic graft-vs.-host-disease (cGVHD), by the assessment of antibody levels at 30-45 days after the second dose of vaccine. RESULTS: After the second dose of vaccine, 23 out of 31 patients (74%) showed a positive immune response. The presence of severe cGVHD or Ig deficiency identified 7 out of 8 (85%) of non-responders. The median absolute cluster of differentiation 19 (CD19) count was significantly lower in non-responders vs. responders (109/µl vs. 351/µl). Underlying pathology, comorbidities, type of donor, time intervals from transplant and cluster of differentiation 3/cluster of differentiation 4/cluster of differentiation 8 (CD3/CD4/CD8) subsets were not significantly associated with an effective immune response to vaccination. CONCLUSIONS: Despite the limited sample of patients enrolled, our findings suggest that hypogammaglobulinemia and cGVHD could be associated with poor humoral response to the BNT162b2.

SEROLOGIC RESPONSE TO THE SECOND AND THIRD DOSE OF THE SARS-COV-2 VACCINE IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA: RESULTS OF A PROSPECTIVE, CENTRALIZED, MULTICENTER STUDY

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.

Should be a Third Dose of BNT162b2 mRNA COVID-19-Vaccine Administered in Patients with Myelofibrosis Under Ruxolitinib?

[Formula presented] Introduction. Patients with Myelofibrosis (MF) are considered fragile and thus eligible in Italy for COVID-19 BNT162b2 mRNA vaccination. According to the International Prognostic Scoring System (IPSS), patients with intermediate and high MF, may receive clinical benefits from ruxolitinib, the first approved JAK1/JAK2 inhibitor. Given the potent anti-inflammatory properties of ruxolitinib against immunocompetent cells, we previously reported a lower but non-statistically absolute IgG anti-Spike humoral response in vaccinated MF patients treated with ruxolitinib. In the present report we extended the cohort of MF patients. Methods. All MF patients received 2 injections of 30 ug per dose of BNT162b2 mRNA COVID-19 vaccine 3 weeks apart, according to the standard protocol. After injection, mild pain at the injection site was frequently reported. No serious adverse events were registered. The serum level of IgG anti-Spike glycoprotein was tested after a median time of 45 days (range 40-60) from the second vaccine dose, using the approved anti-SARS-CoV-2 IgG CLIA (LIAISON® SARS-CoV-2 TrimericS IgG assay, Diasorin, Saluggia, Italy). An Arbitrary Units per milliliter (AU/mL) ratio of <12.0 was considered to be negative, 12.0-15.0 AU/mL to be borderline and >15 AU/mL to be positive. A conversion of AU/mL to binding antibody units (BAU/mL) as recommended by the World Health Organization (WHO) guidelines was achieved considering the following equation: BAU/mL = 2.6*AU/mL. Results. Overall, 30 MF patients (median age 65 years, range 48-83) were vaccinated. A diagnosis of primary MF was reported in 21 cases (70%), post essential thrombocythemia-MF in 6 (20%) patients and post polycythemia vera-MF in 3 (10%) patients;23 out of 30 patients (76.6%) were positive for the JAK2V617F, 5 (16.6%) for CALR mutation, 1 (3.3%) for MPL mutation and 1 patient (3.3%) resulted triple negative. Splenomegaly was observed in 14 patients (46%) and 19 (63.3%) reported comorbidities. Nineteen patients (63.3%) were classified as DIPSS low or intermediate-1 risk, and 11 (36.6%) as intermediate-2 or high risk. Fifteen patients (50%) were receiving ruxolitinib, at a median total dose of 20 mg/die (range 20-40 mg) and the remaining 15 patients other treatments (8 patients hydroxyurea and 7 only supportive therapy). None of the patients reported COVID-19 infection neither previous nor subsequently to vaccination. Overall, a positive immune response against COVID-19 was observed in 8 out of 15 patients (53.3%) in the ruxolitinib group, in comparison with 13 out 15 patients (86.6%) in the other treatment group (p=0,046). The absolute IgG anti-Spike value was lower in the ruxolitinib group (median 35.2±49.81) in comparison with the other group (median 226.1±163.9;p=<0.001), Figure 1. In univariate analysis, only ruxolitinib treatment was found associated with a lower humoral immune response to the vaccine. Conclusions. MF patients under ruxolitinib achieved a lower humoral immune response in comparison with MF patients who underwent other treatments. No COVID-19 infection was observed in both groups after vaccination, after a median follow up of 3 months since the second dose. Whether patients with a potential insufficient humoral response to vaccine will benefit from a third dose of BNT162b2 mRNA COVID-19 vaccine is a matter of further investigation. Our preliminary data need to be confirmed in larger cohort of MF patients. [Formula presented] Disclosures: Murru: Abbvie: Consultancy, Honoraria, Other: travel and accommodation;Janssen: Consultancy, Honoraria.