Newer targeted drugs for chronic lymphocytic leukemia also appear to have a beneficial impact on underlying autoimmune cytopenias (AICs), results of a large retrospective study suggest.
Many autoimmune cytopenias improved or resolved during treatment with ibrutinib, idelalisib, or venetoclax, according to authors of the study, which appears in the journal Blood.
Treatment-emergent autoimmune cytopenias were seen in a “negligible portion” of patients overall, according to the report. The prevalence was about 1% each for patients treated with ibrutinib or idelalisib, though seen more frequently (at 7%) among patients who received venetoclax.
Nevertheless, treatment-emergent autoimmune cytopenias were “easily manageable” without interventions such as steroids and rituximab, and without need to interrupt the targeted treatment for chronic lymphocytic leukemia (CLL), according to the authors, led by Candida Vitale, MD, PhD, of the department of molecular biotechnology and health sciences at the University of Torino in Italy.
“Ibrutinib, idelalisib, and venetoclax have a beneficial impact on CLL-related preexisting AICs, achieving in most patients, in parallel with the consolidated antitumor efficacy, an effective control of the autoimmune phenomena,” Dr. Vitale and coauthors wrote in their report.
Study results
The retrospective study included 815 patients, of whom 572 were treated with ibrutinib, 143 with idelalisib plus rituximab, and 100 with venetoclax. Nine percent of ibrutinib-treated patients and 12% of venetoclax-treated patients also received an anti-CD20 monoclonal antibody, rituximab or obinutuzumab.
One hundred and four patients (13%) had preexisting autoimmune cytopenias, though the majority were resolved or controlled at the time targeted therapy was started.
Of patients with autoimmune cytopenias that were unresolved at the beginning of targeted therapy, 80% improved or resolved after starting targeted treatment, authors reported.
Most patients who developed autoimmune cytopenias on treatment had high-risk features such as unmutated IGHV, del(17)p, or TP53 mutation, according to the report.
Those treatment-emergent autoimmune cytopenias were seen in 1% of the ibrutinib group, 0.9% of the idelalisib group, and 7% of the venetoclax group. Out of 12 total treatment-emergent autoimmune cytopenias, all but 2 were resolved or controlled with dose reductions or temporary suspensions and use of steroids or rituximab, the report shows.
The higher incidence of autoimmune cytopenias in the venetoclax group held steady even when considering just the patients who had relapsed/refractory disease or had at least two prior lines of therapy, suggesting a “more meaningful” incidence, compared to what was observed for ibrutinib and idelalisib, the investigators said.
“However, the risk of autoimmune cytopenia episodes should not limit the use of venetoclax, considering the strong efficacy of this drug in treating patients with CLL, including those with high-risk features, and the possibility of effectively managing autoimmune complications, mostly without treatment interruption,” they concluded in their report.
Implications for patients with CLL
Findings of this study indicate that targeted therapies are effective for managing both CLL and autoimmune cytopenias, according to Carol Moreno, MD, PhD, of Hospital Sant Pau in Barcelona.
Dr. Carol Moreno
Moreover, the targeted therapies do not appear to change the overall prevalence of autoimmune cytopenias, compared to untreated patients, Dr. Moreno said in a commentary on the findings also published in Blood.
“These results are consistent with the concept that targeted therapies are not associated with a higher risk of autoimmune cytopenias, and that, if present, can be managed with immunosuppressive agents,” she wrote.