Not the right partner?
“The results of this study would suggest that ibrutinib is not the right agent. This is not altogether unexpected,” Dr. Galardy said. “The benefit of ibrutinib in adults with mature B-cell lymphoma is primarily based on biological characteristics of lymphomas that develop in older individuals.”
He noted that mature B-cell lymphoma in older adults is often of the activated B-cell subtype, which frequently has mutations that make it sensitive to ibrutinib. In contrast, children, adolescents, and young adults more commonly have the germinal center B-cell subtype that doesn’t have similarly targetable mutations.
He added that, although the reasons for poor prognosis in patients with prior rituximab exposure are unclear, “it is likely that patients who have recurrent or refractory disease after therapy that included rituximab may have developed resistance to this drug. Since both arms of this study included rituximab as a component of the therapy, the patients with prior exposure to this drug may have had reduced benefit of the additional rituximab, compared with those who had not received the drug before.”
The SPARKLE trial was funded by Janssen Research & Development. Dr. Burke disclosed consultancy fees from Janssen and others. Dr. Galardy is an equity holder in Abbott and AbbVie.