particularly in those with B-cell malignancies, an observational study suggests.
Dr. Gwen Nichols
The findings, based on a review of COVID-19 booster vaccine recipients with B cell–derived hematologic malignancies from the prospective Leukemia & Lymphoma Society National Registry, provide valuable information about booster vaccinations in this vulnerable population, according to LLS chief medical officer and lead study author Gwen Nichols, MD.
The LLS Registry data
Of 49 patients included in the review, 38 failed to make antispike (anti-S) antibodies after full vaccination, and of those, 21 seroconverted after booster vaccination and 11 experienced seroelevation after the booster.
The patients who did not seroconvert were seronegative after initial vaccination and experienced no change in antibody level after the booster vaccination. In contrast, the 21 who seroconverted had a median 23.1 AU/ml increase in antibody level, Dr. Nichols, along with LLS chief scientific officer Lee M. Greenberger, PhD,and their colleagues reported online Sept. 6, 2021, in Cancer Cell.
Similar proportions of seroconverted patients had low-level responses between 2.2 and 23.1 AU/mL and robust response between 125 and 2,500 AU/mL, they noted. The 11 patients with seroelevation were seropositive after full vaccination and demonstrated a median increase of 2,128 AU/mL in antibody level after the booster vaccination.
Therapy effects on vaccine response
Outcomes of the current analysis also confirmed the authors’ previous finding, which suggested that “both disease and therapies can affect the serological response to vaccination,” they wrote, explaining that, among the 12 patients who received no malignancy-targeted treatments in the past 2 years, only 1 was a nonresponder, 7 demonstrated seroconversion, and 4 demonstrated seroelevation.
“In contrast, among the 21 patients who completed therapy with anti-CD20 antibodies either alone or in combination with other therapies, 12 patients were nonresponders, 7 patients demonstrated seroconversion, and 2 patients demonstrated seroelevation,” they added.
The authors also noted that five of seven patients who completed anti-CD20 antibody therapy alone or in combination with chemotherapy at least 7 months prior to the booster vaccination demonstrated seroconversion or seroelevation, whereas many of the patients with recent or maintenance anti-CD20 antibody therapy before the booster vaccination failed to seroconvert afterward.
In light of previous findings showing B-cell recovery begins 6-9 months after rituximab therapy, these data suggest that recent anti-CD20 antibody-containing treatment regimens may suppress booster vaccination response, the authors wrote.
The current data also support the group’s prior finding that use of a Bruton tyrosine kinase inhibitor may suppress vaccine response: Of the patients in the current study who experienced seroelevation and were treated with a BTKi, two discontinued BTKi therapy 7-23 months prior to booster vaccination, one maintained a low dose of ibrutinib before booster vaccination, one maintained BTKi therapy continuously before and after the booster, and the two who experienced marked seroconversion after booster vaccination stopped BTKi therapy at least 4 months prior.
Conversely, five patients with a very weak seroconversion and two patients with moderate seroconversion maintained BTKi therapy during booster vaccination.
“These data suggest that BTKi therapy can interfere with a response to booster vaccination,” they wrote, noting, however, that “it is encouraging that seven patients ... maintained on a BTKi seroconverted or experienced seroelevation after booster vaccination and [this] is consistent with a previous report on one patient.”