Neutralizing Antibody responses against SARS-CoV-2 in cancer patients after the first mRNA-1273 vaccine dose

ABSTRACT

Background: Vaccination against SARS-CoV-2 could be an important preventive strategy against COVID-19 for cancer patients (pts), but its efficacy and safety in these pts is largely unknown. Herein, we report the development of neutralizing antibodies (NAbs) against SARS-CoV-2 in cancer pts after the 1st dose of the mRNA-1273 vaccine. Patients and methods: A cohort of pts with solid tumors from IRCCS MultiMedica and San Giuseppe Hospital, Milan, were enrolled in the VITTORIA (VaccInazione anTi-COVID-19, moniTORaggio Della rIsposta Anticorpale) project, a prospective observational cohort study, conducted by IRCCS MultiMedica, designed to investigate trend of immunoglobulin G (IgG) in serum samples of volunteers who undergo anti-COVID vaccination in Italy. Seroprevalence was assessed through TGS COVID-19 IgG chemiluminescent immunoassays. Cut-off for positivity was defined as >11.5 AU/ml. These pts are vaccinated with mRNA-1273 vaccine and undergo to a maximum of 4 IgG evaluations during time at the 1st and 2nd vaccine administration and after 2 weeks from each administration. In this preliminary analysis, we evaluated median values (range interquartile (IQR)) of IgG during the first 3 time points and we assessed trend with non-parametric Sign test for dependent samples. Results: 61 pts were enrolled in April 2021. 68.9% were females with a mean age of 63.7?}10.5 yrs. 28 have breast cancer, 7 lung, 15 gastrointestinal, 3 prostate, 2 kidney, 2 head and neck, 4 gynecological cancer. 44.3% were on chemotherapy (CT), while 55.7% on non-CT treatment (i.e target or immunotherapy). Median baseline IgG value was 0.0 AU/ml (IQR 0.0-0.0) and it statistically increased after 2 weeks (4.4 AU/ml, IQR 0.0-14.9, p<0.0001). At 2nd dose, IgG was available until today for 42 pts (68.9%) and the median value was 12.5 AU/ml (IQR 5.4-38.9, p<0.0001). 34.4% had positive IgG value 2 weeks after the 1st dose and 52.4% at 2nd dose. IgG value increases independently from treatment (CT vs non-CT), steroid use and tumor subtype, with a trend towards positivity for non- CT treatment (p=0.067). No serious adverse events vaccine- related were reported and no COVID-19 infection occurs after 1st dose. Conclusions: Our preliminary data indicate that the first dose of mRNA-1273 vaccine leads to initial production of NAbs against SARS-CoV-2 in a cohort of cancer pts. Enrollment is still ongoing and future analysis will be performed to assess the increase and duration of NAbs in pts with solid tumors.