Researchers have found that patients with chronic lymphocytic leukemia (CLL) should continue to receive Bruton tyrosine kinase (BTK) inhibitors while being vaccinated against COVID-19 infections, according to a recent study published by Cook et al in The Lancet Haematology.
Background
CLL is the most common type of leukemia among adult patients and is associated with an increased risk of infection. Patients with CLL—particularly those receiving treatment with a BTK inhibitor such as ibrutinib or acalabrutinib—often have lower antibody responses to vaccination compared with the general population.
Study Methods and Results
In the IMPROVE trial, the researchers examined whether a 3-week pause in BTK inhibition around the time of COVID-19 vaccination (1 week prior to vaccination and 2 weeks following vaccination) would improve the antibody response in patients with CLL compared with continued therapy without interruption. They randomly assigned 99 patients with well-controlled CLL who had received BTK inhibitors for over 1 year from 11 hospitals across the United Kingdom to the BTK inhibitor pause group or continued treatment group. Immune responses were measured prior to vaccination as well as 3 and 12 weeks postvaccination.
Despite positive results from prior observational studies, the researchers demonstrated no statistically significant difference in antibody levels between the patients who paused their BTK inhibitor therapy and those who continued their treatment as usual. Further, the quality of the antibody response and cellular immunity was comparable among the patients in both groups. The findings remained consistent 12 weeks postvaccination.
Conclusions
Although the researchers found no evidence that a pause in BTK inhibition improved the immune response to COVID-19 vaccination among patients with CLL, the study highlighted the variable responses in this patient population.
The researchers are currently analyzing the blood samples collected during the trial to better understand how patients with CLL respond to COVID-19 vaccination as well as strategies to heighten this response.
“Our study provides clarity for patients [with CLL] and their health-care providers that pausing BTK [inhibitor] therapy around the time of COVID-19 vaccination does not improve their antibody response and should not be recommended in clinical practice,” concluded senior study author Helen Parry, MBChB, MSc, PhD, MRCP, FRCPath, Associate Professor in the Department of Immunology and Immunotherapy at the University of Birmingham and a researcher in the Cancer Inflammation theme at the National Institute for Health and Care Research Birmingham Biomedical Research Centre.
Disclosure: For full disclosures of the study authors, visit thelancet.com.
