COVID-19 vaccines elicit weaker antibody response in multiple myeloma patients

Patients with myeloma mount a neutered humoral immune response following vaccination for the coronavirus disease 2019 (COVID-19), especially when receiving antibody therapy, a recent study has found.

Researchers enrolled 276 patients (median age 74 years, 54.7 percent men) with plasma cell neoplasms, of whom 213 were diagnosed with multiple myeloma (MM), 38 with smouldering myeloma (SMM), and 25 with monoclonal gammopathy of undetermined significance (MGUS). A parallel group of 226 healthy controls was also included. All participants had been vaccinated with either both doses of the BNT162b2 shot or one does of the AZD1222 vaccine.

Twenty-two days after the first vaccine dose, patients with malignancies showed significantly lower median levels of neutralizing antibody (Nab) inhibition titres than controls (27 percent vs 38.7 percent; p<0.001).

Moreover, 42.4 percent (n=117) of patients tested positive for the presence of NAbs, defined as titres ≥30 percent, significantly lower than the 64.2-percent positivity rate in controls (p<0.001). NAb titres ≥50 percent was defined as the threshold for clinically relevant viral inhibition and was achieved by 19.9 percent and 32.3 percent of the respective participant subgroups (p=0.002).

Such a trend of weaker NAb responses in patients vs controls remained significant up to 4 weeks after the second dose of the BNT162b2 vaccine or seven weeks after the AZD1222 shot.

Similarly, patients on belantamab mafodotin or anti-CD38 monoclonal antibody therapy showed a significantly lower day-50 median NAb titre relative to those on other treatment regimens (31.9 percent vs 62.8 percent; p=0.005).