CLL Patients Responded to Influenza Vaccine

Patients with chronic lymphocytic leukemia (CLL) taking ibrutinib showed an antibody response to the influenza vaccine, according to a data from a small study published as a research letter in JAMA Oncology.

According to the letter, patients with CLL have immune dysfunction, with infections accounting for as many as 60% of deaths in these patients. To try to combat these infections, influenza vaccinations are recommended; however, patients often have impaired responses to the vaccinations. Specifically, it was unknown whether patients with CLL taking ibrutinib, a Bruton tyrosine kinase inhibitor, could mount an immune response to vaccination.

According to this research, by Clare Sun, MD, of the National Heart, Lung, and Blood Institute in Bethesda, Maryland, and colleagues, “up to 74% of patients achieved seroprotective titers against common influenza viruses after vaccination.”

These data were taken from a phase II trial of single-agent ibrutinib in which patients were offered the influenza vaccination containing A/California/7/2009 (A/CA/09; H1N1) pdm09, A/Texas/50/2012 (A/TX/12; H3N2), and B/Massachusetts/2/2012 (B/MA/12) viruses. Nineteen patients received one dose of the vaccine. The researchers measured hemagglutinin inhibition antibody titers at baseline and 3 months after vaccination.

More than one-quarter (26%) of patients had seroconversion for at least one strain (95% CI, 9.2%–51.2%). Seroconversion for the A/CA/09 strain occurred in three patients (16%), the A/TX/12 strain in five patients (26%), and the B/MA/12 strain occurred in two patients(11%).

In addition, the researchers observed significant increases in geometric mean titers against all three virus strains:

• A/CA/09: before vaccination, 19.3 vs 27.8 after vaccination (P = .04)
• A/TX/12: before vaccination, 17.9 vs 38.6 after vaccination (P = .002)
• B/MA/12: before vaccination, 9 vs 12.9 after vaccination (P = .02)

More than one-third of patients (37%) developed influenza within 6 months of vaccination, including one patient who had a grade 3 infection with influenza A subtype H3.

The researchers acknowledged several limitations to the study including the small sample size and incomplete laboratory confirmation of influenza infection.

“Given our data, additional studies are warranted to evaluate whether ibrutinib impairs or improves vaccine response relative to other treatment,” the researchers wrote.