By IDSE News Staff
Patients with cancer who receive chemotherapy and some targeted therapies may not mount an adequate immune response to the messenger RNA (mRNA) COVID-19 vaccines, which makes booster vaccination even more important, according to a new study by researchers at Mayo Clinic Cancer Center.
The researchers wanted to know whether patients with cancer who were receiving chemotherapy or cyclin-dependent kinase 4/6 inhibitors (CDK4/6i)—abemaciclib (Verzenio, Lilly), palbociclib (Ibrance, Pfizer), and ribociclib (Kisqali, Novartis)—developed a humoral response to the SARS-CoV-2 vaccines.
In this retrospective, cross-sectional study conducted at three Mayo cancer treatment centers, investigators measured the antibody response in 201 patients, 18 years of age or older, after they received two doses of mRNA vaccine. Patients included in the study were not receiving immunosuppressants and had not been diagnosed previously with COVID-19 (61 immunocompetent, 91 with hematologic malignancy and 49 with solid tumor). The study was done between Jan. 1 and May 10, 2021, and involved clinics in Minnesota, Florida and Arizona (Mayo Clin Proc Innov Qual Outcomes 2021 Dec 12. https://doi.org/10.1016/j.mayocpiqo.2021.12.004).
They compared immunocompetent patients (healthy without cancer or with a history of solid tumor, but not receiving immunosuppressants) and patients with hematologic or solid tumors who were on active treatment. Ninety-five patients received the Moderna vaccine and 106 received the Pfizer-BioNTech vaccine.
A significantly greater proportion of immunocompetent patients (97%) achieved an antibody titer of at least 500 U/mL compared with patients with hematologic (8%) or solid malignancies (55%) (P<0.001). Fifty-three percent of hematologic malignancy patients and 8% of solid tumor patients receiving therapy showed no antibody response (<0.8 U/mL). Despite receiving two doses of vaccine, two patients subsequently developed breakthrough COVID-19 infection.
Although CDK 4/6 inhibitors are not considered to be as immunosuppressive as chemotherapy, the patients who took them developed less optimal neutralizing antibodies, according to Saranya Chumsri, MD, a Mayo Clinic hematologist and oncologist, and the author of the paper.
Dr. Chumsri recommended that antibody levels be tested in these patients after vaccination, and they should consider receiving booster vaccinations for COVID-19.
“It is important for patients with cancer who are receiving chemotherapy to receive a COVID-19 vaccine,” Dr. Chumsri said.
