In a single-institution retrospective study reported in a research letter in JAMA Oncology, Ollila et al found a low rate of seroconversion after COVID-19 vaccination among adult patients with hematologic malignancies.
The study included 160 patients at Rhode Island Hospital receiving the Pfizer-BioNTech (n = 96), Moderna (n = 50), or Johnson & Johnson (n = 11) vaccines between February and April 2021. In total, 105 patients had received a B-cell–depleting monoclonal antibody (most commonly rituximab, n = 85) or bispecific CD3/CD20 antibodies (n = 12) to treat their cancer.
Seroconversion documented by positive results on the qualitative SARS-CoV-2 total antibody assay occurred in 63 patients (39%, 95% confidence interval [CI] = 32%–47%). Among 47 patients tested with a quantitative IgG assay, patients without seroconversion on the qualitative assay had median anti–COVID-19 IgG levels of 8 AU/mL vs 4,289 AU/mL among those with seroconversion.
Our findings raise a concern that patients with hematologic cancers, particularly those receiving B-cell–depleting immunotherapy, may not gain adequate protection from vaccination, and as observed in our cohort, may still develop a potentially fatal infection.— Ollila et al
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Seroconversion on the qualitative assay was significantly less common among patients exposed vs not exposed to B-cell/plasma cell–depleting monoclonal antibodies (30 [29%] of 105; risk difference = 31%, 95% CI = 16%–47%, P < .001), as well as among those with active malignant disease (22 [27%] of 88) vs those in remission after treatment (31 [49%] of 63; risk difference = 22%, 95% CI = 7%–38%, P = .009) or those undergoing watchful waiting (10 [67%] of 15; risk difference = 40%, 95% CI = 14%–66%, P = .0060).
Median time from last chemotherapy treatment to vaccination was 8.4 months among those with seroconversion vs 0 months among those without seroconversion (P = .005). Among 32 patients who completed chemotherapy more than 12 months before vaccination, 69% had seroconversion, compared to 24% of 97 vaccinated within 12 months of their last treatment.
Quantitative antibody response to vaccination was lower among patients with vs without exposure to B-cell/plasma cell–depleting antibodies (median IgG = 20.7 AU/mL vs 489 AU/mL) and among those with active malignant disease vs those in remission after treatment and those undergoing watchful waiting (median IgG = 28 AU/mL vs 1,911 AU/mL and 1,950 AU/mL). A total of three patients developed COVID-19 infections after vaccination (with no detectable postvaccination antibodies), with one patient dying from infection.
The investigators concluded, “Our findings raise a concern that patients with hematologic cancers, particularly those receiving B-cell–depleting immunotherapy, may not gain adequate protection from vaccination, and as observed in our cohort, may still develop a potentially fatal infection. These patients may benefit from ongoing protective measures, including masks, social distancing, and screening. Consideration should be made to prioritizing vaccination for family members and caregivers to protect the patients themselves. With possible infection, we recommend testing regardless of vaccination status, and treatment with COVID-19–specific monoclonal antibody therapy.”
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.