A single-institution, retrospective cohort study reported the incidence of opportunistic infections among patients with hematological malignancies who received ibrutinib and identified potential patient risk factors. The study findings were published online May 13, 2019, in Leukemia.

The records of 566 patients with hematologic malignancies who received ibrutinib between June 2010 and March 2016 were retrospectively reviewed for events of opportunistic infection, which included pneumocystis jirovecii pneumonia, invasive and disseminated fungal infections, progressive multifocal leukoencephalopathy, toxoplasmosis, viral disseminated infections, and atypical bacterial infections.

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Most patients (80.9%) were clinical trial participants, most had chronic lymphocytic leukemia (73.7%), and 30.9% received ibrutinib in combination with another agent, with an anti-CD20 monoclonal antibody being the most common agent (81.7%).

Overall, the cohort had 1225 patient-years of ibrutinib exposure and the median exposure for an individual patient was 1.98 years (range, 0.008 – 6.40 years). 

At a median follow-up of 2.69 years (range, 0.03-6.40 years), 23 cases of opportunistic infections occurred, which yielded an incidence rate of 1.9 per 100 person-years (95% CI, 1.2-2.8). Most of the opportunistic infection cases were invasive fungal infections (17 patients, 73.9%), with invasive aspergillosis being the most common type (12 patients, 52.1%). From the time of opportunistic infection diagnosis, the median survival was 1.39 years (95% CI, 0.38-not reached).  

According to a multivariate analysis, receipt of 3 or more prior lines of therapy (hazard ratio [HR], 2.87; 95% CI, 1.12-7.35; P =.028), diabetes (HR, 3.63; 95% CI, 1.50-8.77; P =.004), and liver disease (HR, 7.53; 95% CI, 2.14-26.49; P =.002) were each independently associated with developing an opportunistic infection during ibrutinib treatment.

“In conclusion, we found that invasive fungal infections occur at a low frequency during ibrutinib therapy, with aspergillus being the most common infectious organism,” the study authors wrote. “Further work is needed to confirm risk factors and determine the optimal monitoring and prophylaxis for these patients.”

Reference

  1. Rogers KA, Mousa L, Zhao Q, et al. Incidence of opportunistic infections during ibrutinib treatment for B-cell malignancies [published online May 13, 2019]. Leukemia. doi: 10.1038/s41375-019-0481-1