Immunogenicity and Safety of the BNT162b2 mRNA COVID-19 Vaccine Among Actively Treated Cancer Patients

Abstract

Background: Activity and safety of the SARS-CoV-2 BNT162b2 vaccine in actively treated patients with solid tumors is currently unknown.

Methods: We conducted a retrospective study of 326 patients with solid tumors treated with anticancer medications to determine the proportion of cancer patients with immunogenicity against SARS-CoV-2 following 2 doses of the BNT162b2 vaccine. The control group comprised 164 vaccinated healthy adults. Anti-SARS-CoV-2 S immunoglobulin G antibodies were measured using a level greater than 50 AU/mL as a cutoff for seropositivity. Information on adverse effects was collected using a questionnaire. All statistical tests were 2-sided.

Results: Most patients (205, 62.9%) were treated with chemotherapy either alone or with additional therapy; 55 (16.9%) were treated with immune checkpoint inhibitors and 38 (11.7%) with targeted therapy alone; 28 (8.6%) received other combinations. The vaccine was well tolerated, and no severe side effects were reported. Among patients with cancer, 39 (11.9%) were seronegative compared with 5 (3.0%) of the control group (P = .001). Median immunoglobulin G titers were statistically significantly lower among patients with cancer compared with control (931 AU/mL vs 2817 AU/mL, P = .003). Seronegativity proportions were higher in the chemotherapy-treated group (n = 19; 18.8%) compared with the immune checkpoint inhibitor-treated patients (n = 5; 9.1%) and with those treated with targeted therapy (n = 1; 2.6%) (P = .02). Titers were also statistically significantly different among treatment types (P = .002).

Conclusions: The BNT162b2 vaccine is safe and effective in actively treated patients with cancer. The relatively lower antibody titers and lower proportion of seropositive patients, especially among chemotherapy-treated patients, call for continuing the use of personal protective measures in these patients, even following vaccination.

Figure 1.

Local and systemic side effects following BNT162b2 mRNA vaccination among actively treated cancer patients. Bars show the proportion of participants reporting on each side effect. Only side effects reported by more than 1% of the patients are presented.

Figure 2.

Lower SARS-CoV-2 S immunoglobulin G (IgG) antibody (Ab) among patients with solid cancers. SARS-CoV-2 S IgG Ab values in serum samples of actively treated patients with cancer (N = 326 patients) and healthy controls (N = 164). Box plots represent serum SARS-CoV-2 S IgG Ab values. Ends of the boxes are the upper and lower quartiles, and medians are marked by horizontal lines inside the boxes. Every dot represents 1 participant’s level of antibodies. Error bars represent the range between minimal and maximal points. The y-axis (log₁₀ scale) represents SARS-CoV-2 S IgG Ab values transformed to log₁₀ scale. The statistical significance of the differences was determined using the 2-sided Mann-Whitney test adjusted for age and sex. Dashed line represents cutoff level of seropositivity (50 AU/mL). Cancer patients had lower plasma levels of SARS-CoV-2 S IgG Ab compared with healthy controls (P = .003).

Figure 3.

Differences in the distribution of SARS-CoV-2 S immunoglobulin G (IgG) antibody (Ab) across different cancer types. SARS-CoV-2 S IgG Ab values in serum samples of actively treated patients with cancer (N = 326 patients) are shown by cancer type. Box plots represent serum SARS-CoV-2 S IgG Ab values. Ends of the boxes are the upper and lower quartiles, and medians are marked by horizontal lines inside the boxes. Every dot represents 1 participant’s level of Ab. Error bars represent the range between minimal and maximal points. The y-axis (log₁₀ scale) represents SARS-CoV-2 S IgG Ab values transformed to log₁₀ scale. The dashed line represents cutoff level of seropositivity (50 AU/mL). Statistical analyses were determined using the Kruskal-Wallis test and the Mann-Whitney test with Bonferroni correction for multiple comparisons. Patients with gynecological cancers had higher SARS-CoV-2 S IgG Ab values compared with patients with gastrointestinal cancers (P = .02, 2-tailed). All other comparisons did not reach statistical significance. NSCLC = non-small cell lung cancer.

Figure 4.

Differences in the distribution of SARS-CoV-2 S immunoglobulin G (IgG) antibody (Ab) in patients receiving different anticancer treatments. SARS-CoV-2 S IgG Ab values in serum samples of cancer patients treated with chemotherapy (n = 101), immunotherapy (n = 55), and targeted therapy (n = 38, green dots). Box plots represent serum SARS-CoV-2 S IgG Ab values. Ends of the boxes are the upper and lower quartiles, and medians are marked by horizontal lines inside the boxes. Every dot represents 1 participant’s level of antibodies. Error bars represent the range between minimal and maximal points. The y-axis (log₁₀ scale) represents SARS-CoV-2 S IgG Ab values transformed to log₁₀ scale. The dashed line represents the cutoff level of seropositivity (50 AU/mL). Statistically analyses were determined using the Kruskal-Wallis test and the Mann-Whitney test with Bonferroni correction for multiple comparisons. Patients treated with targeted therapy had higher SARS-CoV-2 S IgG Ab values compared with patients treated with chemotherapy (P = .001, 2-tailed). All other comparisons did not reach statistical significance. ns = nonstatistically significant.