Chronic lymphocytic leukemia (CLL) is a disease that puts patients at higher risk of contracting infections.1,2 In fact, infections (usually pneumonia) are the most likely cause of death for patients with CLL.1 Patients with CLL are at higher risk for severe infections because both the disease and CLL treatments can suppress their immune system, leading to abnormally low neutrophil (white blood cell) counts, limiting the body’s ability to fight off infections.3
In recent years, targeted therapies such as ibrutinib have become the standard of care for treating patients with CLL.4 Despite their improved efficacy, targeted therapies are associated with a similar infection risk as the older chemoimmunotherapy combinations that they have largely replaced.5 For instance, about 21% of patients receiving ibrutinib had a serious infection in clinical trials.6 That said, guidelines for the prevention of infections in patients with CLL who receive ibrutinib are notably lacking.2
To identify factors that are associated with severe bacterial, viral, and fungal infections in CLL patients receiving ibrutinib, researchers at a single center in Moscow identified every infection that occurred in 240 patients over a 3.5-year period.2
A total of 525 infections were recorded in 183 patients during this study.2 Most infections (73%) were bacterial or mixed infections, whereas 22% were viral, and 6% were fungal.2 Of these infections, 37% of bacterial infections were graded as severe, compared with 28% of viral and 8% of fungal infections.2
Of the patients who had infections over the course of this study, 87% had >1 measured infection.2 Risk factors for having a severe bacterial infection during a 12-month period included being male, having decreased physical functioning (ie, being physically incapable of carrying out any work activities), and having an abnormally low number of infection-fighting white blood cells (called neutrophils), medically termed neutropenia, at the start of the study.2 For serious viral infections, the only risk factor identified in the study was having had >3 lines of prior CLL therapy.2 Risk factors identified for having a serious fungal infection over the course of a year were the use of corticosteroids, having neutropenia, and having had a prior splenectomy.2
Overall, these data provide insight into which patients are at highest risk of severe infections when receiving ibrutinib to treat their CLL. Some patients, including those who have neutropenia or are being treated with corticosteroids, may benefit from a course of preventive antibacterial or antifungal treatment to minimize their risks of contracting a serious infection.2
References
- Chronic Lymphocytic Leukemia Society. Chronic lymphocytic leukemia (CLL) FAQs. https://cllsociety.org/questions-answers. Accessed November 3, 2021.
- Dmitrieva E, Nikitin E, Markova E, et al. Infections in CLL patients receiving ibrutinib: incidence and predisposing factors. Presented at the 2019 European Hematology Association Meeting; June 15, 2019. Abstract PS1154.
- Blixt L, Bogdanovic G, Buggert M, et al. Covid-19 in patients with chronic lymphocytic leukemia: clinical outcome and B- and T-cell immunity during 13 months in consecutive patients [published online ahead of print, September 25, 2021]. Leukemia. 2021;1-6.
- Patel K, Pagel JM. Current and future treatment strategies in chronic lymphocytic leukemia. J Hematol Oncol. 2021;14:69-89.
- Brem EA, O’Brien S. Frontline management of CLL in 2021 [published online ahead of print, July 21, 2021]. JCO Oncol Pract. 2021;OP2100258.
- IMBRUVICA (ibrutinib). [prescribing information]. Horsham, PA: Janssen Biotech; 2020.