Study provides further insight into COVID-19 vaccine response among patients with cancer
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Most patients with cancer demonstrated antibody responses to COVID-19 vaccination after two doses of the mRNA-1273 vaccine, according to an observational study published in JAMA Oncology.
The vaccine conferred substantially higher antibody levels among patients seropositive before vaccination, with higher rates of seroconversion among those with solid tumor cancers vs. hematologic malignancies, researchers from the Moffitt Cancer Center reported.
“Maybe a little bit surprisingly, the vast majority of patients were able to mount an antibody response to the vaccine after the second dose,” Jeffrey E. Lancet, MD, professor of oncologic sciences at University of South Florida and chair of the malignant hematology department at Moffitt Cancer Center, told Healio. “There were definitely subsets of patients who were much less likely to mount an antibody response and, not surprisingly, those patients turned out to be primarily those with B-cell malignancies.”
Background and methodology
When Lancet and colleagues embarked on the research, few data existed on the ability of the mRNA-1273 vaccine (Moderna) to elicit a response in patients with cancer, who stood to benefit the most from COVID-19 vaccination.
“The main impetus for this study was to gain an understanding of whether patients with cancer, who are thought to be more immunosuppressed in general, would be able to mount an adequate antibody response to the vaccine,” Lancet said.
The analysis included 515 adults with cancer (mean age, 64.5 years; 50.9% women; 93% white), including 301 with hematologic malignancies and 214 with solid tumors, who had received their first mRNA-1273 dose between Jan. 12 and Jan. 25, 2021, and agreed to blood tests before and after vaccination.
Researchers obtained cancer diagnoses and treatments from medical record review. They assessed seroconversion after each vaccine dose and immunoglobulin G levels against COVID-19-spike protein immediately prior to the first and second vaccine doses and 57 days (plus or minus 14 days) after the first vaccine dose.
Key findings
Results showed a seropositivity rate after the second vaccine of 90.3% (95% CI, 87.4-92.7). Researchers found significantly lower seropositivity rates among patients with hematologic cancer (84.7%; 95% CI, 80.1-88.6) vs. solid tumors (98.1%; 95% CI, 95.3-99.5), and the lowest rate among patients with lymphoid cancer (70% [n = 77 of 110]; 95% CI, 60.5-78.4).
Researchers also reported a lower seroconversion rate among patients who received a vaccination within 6 months after anti-CD20 monoclonal antibody treatment (6.3%; 95% CI, 0.2-30.2) than among those treated 6 to 24 months earlier (53.3%; 95% CI, 26.6-78.7) or those who never received anti-CD20 treatment (94.2%; 95% CI, 91.7-96.1). They also observed low antibody levels after vaccination in patients treated with anti-CD20 therapy within 6 months before vaccination, those treated with small molecules, and patients with low lymphocyte and IgG levels.
“An important finding was that the high overall response rate — the high overall immunity rate by measuring antibodies — included patients who were on active chemotherapy or had received chemotherapy within a few months,” Lancet said. “With the exception of the B-cell patients, it was reassuring to see that patients who were on active therapy or recently received active therapy were still likely to mount an antibody response.”
Implications
Lancet told Healio the overarching message is that patients with cancer should be vaccinated against COVID-19, as there is strong reason to believe they will mount an effective antibody response.
But he said these data represent only one piece of the puzzle. It will be vital to find out whether the immune response they observed translates into clear antiviral efficacy, as well as if other components of the immune system can make up for what’s lacking in the B-cell, antibody response side, he said.
“The clinical piece is missing, which tells us for sure how many patients came down with COVID-19 who were on the study and how many experienced complications,” Lancet told Healio. “Those are data we’re trying to gather right now and hope will shed some light on the overall incidence of COVID infection and severity in the population of patients with cancer and different subgroups.”
For more information:
Jeffrey E. Lancet, MD, can be reached at H. Lee Moffitt Cancer Center & Research Institute, 3011 Holly Drive, Tampa, FL 33612; email: jeffrey.lancet@moffitt.org.
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