Fungal infections uncommon among ibrutinib-treated patients despite low rate of prophylaxis
FORT WORTH, Texas — Ibrutinib treatment did not appear associated with increased incidence of fungal infections despite a low rate of antifungal prophylaxis among these patients, according to study results presented at HOPA Ahead 2019.
In addition, antifungal prophylaxis did not compromise efficacy or safety outcomes, Kori Daniels, PharmD, PGY2 oncology pharmacy resident at Augusta University Health, and colleagues found.
Ibrutinib (Imbruvica; Janssen, Pharmacyclics) is a Bruton tyrosine kinase inhibitor approved for the treatment of certain patients with chronic lymphocytic leukemia, small lymphocytic lymphoma, mantle cell lymphoma, Waldenstrom macroglobulinemia, marginal zone lymphoma or graft-versus-host disease.
Prior research of patients with CLL showed fungal infection incidence of 4% among those who received ibrutinib and 1.4% of those who did not. The majority of those infections occurred within 6 months of treatment initiation.
“These studies did not address whether these patients were on any kind of antifungal prophylaxis, and there are no guidelines regarding prophylaxis,” Daniels told HemOnc Today. “The purpose of our study was to identify what the prescribing practices were at our institution to determine if these patients were receiving antifungals and, if so, to determine whether they had increased rates of adverse events or worse efficacy outcomes.”
Daniels and colleagues conducted a retrospective chart review of all patients at Augusta AU Medical Center and Georgia Cancer Center who received at least one dose of ibrutinib.
The rate of antifungal prophylaxis served as the primary outcome measure. Key secondary outcomes included rate of ibrutinib discontinuation due to adverse events, rate of fungal infections, time to cancer progression, time to death from ibrutinib initiation, and reason for death.
Researchers identified 64 eligible patients. The final analysis included 62 patients (median age, 64 years; range, 57-72; 55% women). The most common conditions in the study population included CLL (n = 37), chronic GVHD (n = 8), marginal zone lymphoma (n = 6) and diffuse large B-cell lymphoma (n = 6).
Patients received ibrutinib for a median 307 days (interquartile range, 106-626), and 29 patients (47%) remained on treatment at the time of data collection.
Six patients received antifungals. The one patient (2%) in the study who developed an invasive fungal infection received them as treatment but subsequently died. Five patients (8%) received antifungals as prophylaxis.
“The patients who received antifungal prophylaxis did not experience increased adverse events, none had to stop ibrutinib due to adverse events, and they did not experience disease progression or relapse, so we did not see worse outcomes with these patients,” Daniels said.
Eleven patients died during the study period. Eight (13%) died of malignancy, one died of infection, one died due to failure to thrive, and another died of an undocumented cause.
Eight patients (31%) discontinued ibrutinib due to adverse events.
Researchers reported a median time to cancer progression of 1,250 days (range, 101-624) and median time to death from ibrutinib initiation of 224 days (range, 118-594).
“If a prescriber wanted to prescribe antifungals, I wouldn’t talk them out of it because the safety and efficacy data were fine,” Daniels said. “But if they didn’t want to prescribe an antifungal, I would not encourage them to do so. We did not see high rates of fungal infections, so is it really necessary to expose patients to excess medications and other potential issues?” – by Mark Leiser
Reference: Daniels K, et al. Outcomes for patients receiving ibrutinib with or without antifungal therapy. Presented at: HOPA Ahead 2019; April 3-6, 2019; Fort Worth, Texas.
Disclosures: The authors report no relevant financial disclosures.