Dr. Jeffrey Lancet
Factors including age, gender, race, disease status, lower-intensity active treatment, baseline neutrophil and lymphocyte counts, and past history of stem cell transplant had no effects on seroconversion in the study, which, despite its small numbers, is one of the largest series to date among patients with myeloid cancers. The findings were reported at the annual meeting of the American Society of Hematology.
COVID vaccination “appears to induce a strong antibody response” in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), unlike with B-cell malignancies. “It indicates we should be aggressive about vaccinating such patients,” said senior investigator Jeffrey Lancet, MD, a blood cancer specialist at Moffitt, when he presented the findings at the meeting.
Presentation moderator Laura Michaelis, MD, a hematologist-oncologist at the Medical College of Wisconsin, Milwaukee, agreed.
The “strong antibody response in this group,” coupled with its high risk for severe COVID, “confirm the importance of these patients getting vaccinated,” she said.
Thirty patients with AML and 16 with MDS were included in the review. Most patients were in remission at the time of vaccination, but a third were in active treatment, including six on hypomethylating agents, six on targeted therapies, two on luspatercept, and one on lenalidomide. Thirty-two patients (69.6%) were a median of 17 months past allogeneic stem cell transplant.
Overall, 69.6% of patients developed IgG against spike proteins after the first shot and 95.7% of patients after the second dose, with a large increase in titer levels from the first to the second dose, from a mean of 315 AU/mL to 3,806.5 AU/mL following the second dose.
“Lab and clinical variables did not affect the antibody positivity rate after the second dose,” but patients on steroids and other immunosuppressants seemed less likely to respond to the first shot, Dr. Lancet said.
The study, conducted in early 2021, did not include acutely ill patients or those undergoing cheomotherapy induction and other aggressive treatments, because such patients were not being vaccinated at Moffitt during the study period.
The investigators measured anti-spike IgG by ELISA at baseline, then again about a month after the first shot and a month after the second shot.
Side effects were common and typically mild, including injection site pain, fatigue, headache, and arm swelling. Two patients with AML relapsed after vaccination.
Patients were a median of 68 years old when they were vaccinated; 58.7% were men; and almost all of the subjects were White. The median time from diagnosis to the first shot was 2 years.
The next step in the project is to study the timing of vaccination and response to it among patients on aggressive treatment and to perform neutralizing antibody assays to correlate IgG response with protection from COVID.
No funding was reported for the study. Investigators had numerous industry ties, including Dr. Lancet, a consultant for Celgene/BMS, Millenium Pharma/Takeda, AbbVie, and other firms. Dr. Michaelis didn’t have any disclosures.