The COVID-19 booster injections generated immune responses in cancer patients who did not have detectable antibodies after the primary vaccination course, the researchers said.
Among seronegative patients, a third dose of the vaccine achieved a seroconversion rate of 56%, reported Balazs Halmos, MD, MS, of the Montefiore Einstein Cancer Center in New York City, and colleagues.
These findings call for “broad efforts to provide a third vaccination for these patients,” they wrote in Cancer cell.
In the study, 99 patients underwent repeated testing for anti-SARS-CoV-2 (anti-S) antibodies after completing their primary vaccine series. While the majority of patients (94% with hematologic malignancies and 100% with solid tumors) maintained detectable anti-S IgG titers> 50 AU / mL at 4 to 6 months, median titer levels fell. significantly during this period – compared to baseline levels of 5,162 AU / mL to 724.6 AU / mL at follow-up (P
The anti-COVID immunity before and after a booster vaccination was then evaluated in 88 patients (median age 69 years) with a diagnosis of cancer (31 with solid tumors and 57 with hematologic malignancies); 73% were on active treatment at the time of their recall.
Of these patients, 70% received the Pfizer-BioNTech vaccine, 25% received the Moderna vaccine, and 5% received the Johnson & Johnson / Janssen vaccine as primary injections. With the exception of eight patients, all received a booster injection with the type of vaccine initially received. The median time since the last vaccination was 177 days.
Sixty-four percent were HIV positive before the booster, while the remaining 36% were HIV negative. All but one HIV negative patient had hematologic malignancies.
Halmos and colleagues found that patients with hematologic malignancies had both a statistically significantly lower pre-boost antibody response, as well as a smaller change in mean anti-S IgG titers after boosting by compared to those with solid tumors (10,034 versus 22,686 AU / mL; P= 0.00263).
Four weeks after the booster vaccination, 70 of 88 patients (80%) had higher antibody levels than before receiving their booster.
Of the 14 patients who remained seronegative after the booster, all had B-cell malignancies. Eight of these patients were on active treatment at the time of their booster vaccination.
Even patients who received treatment within 30 days of the booster vaccination had a statistically significant risk of seroconversion (P= 0.02).
Previous treatment with a Bruton tyrosine kinase inhibitor or anti-CD20 therapy, or both, was significantly associated with a decrease in antibody seroconversion before and after the booster (P= 0.01333) and the title (P= 0.0000575).
While this study showed that additional dosing can boost immunity in cancer patients, it also showed that some will not benefit from a third dose of mRNA, “highlighting the need for continued efforts to to develop valid laboratory correlates of COVID-19 immunity and studies evaluating the potential benefit of subsequent homologous vaccine doses, heterologous vaccinations, passive immunizations and other unique approaches for these patients, ”Halmos wrote and his colleagues.
Halmos did not report any disclosures. Other co-authors have reported multiple relationships with the industry.