Introduction:
People with lymphoid malignancies are at increased risk of severe SARS-CoV-2 infection and death. There is limited data on BNT162b2 (Pfizer) vaccine response in patients with lymphoid cancers compared to the general population.
We assessed the vaccine responses to BNT162b2 in Follicular lymphoma (FL) and Waldenstrom Macroglobulinemia (WM) at Baseline (Timepoint 1) and 21 days after first (Timepoint 2) and second (Timepoint 3) dose. Cohort included: 1) 24 FL patients treated with rituximab-chemotherapy (FLT); 2) 11 FL patients’ treatment-naïve (FLN); 3) 15 WM patients with rituximab-chemotherapy (WMT); 4) 13 WM patients treated with Bruton’s Tyrosine Kinase inhibitors (WMB); 5) 9 WM patients’ treatment-naïve (WMN); 6) 13 Healthy controls.
Methodology:
Immune response was measured by flow cytometric detection of anti-SARS-CoV-2 spike antibodies (AsAb), using our established live cell assay, live virus neutralisation to a panel of variants of concern and antigen-specific T cell responses. Statistical analysis of medians between the cohorts were compared using Mann-Whitney non-parametric test.
Results:
No participants had detectable ASAb at Timepoint 1, confirming no prior SARS-CoV-2 exposure. At Timepoint 2, the median mean fluorescence intensity (MFI) of healthy controls: 60802, was significantly higher than all WM: 0 (p<0.0001), and all FL patients: 1687 (p=0.002). The median MFI of controls was significantly higher than WMN (p=0.036), but not higher than FLN (p=0.28). The median MFI of WMN: 20074, was significantly higher than WMB: 0 (p=0.018). Similarly, FLN: 31476, was significantly higher than FLT: 0 (p=0.01).
Discussion:
There was measurable ASAb in all healthy controls post first dose of BNT162b2. Treatment naïve patients had a better response than treated patients. WMB patients had reduced response compared to treatment-naïve patients. FL chemotherapy-rituximab patients had reduced response compared to the treatment-naïve cohort.
This study is ongoing, results to Timepoint 3 will be reported at the ASI conference.