ATLANTA – Ibrutinib yielded a median progression-free survival (PFS) of nearly 3 years for patients with relapsed or refractory mantle cell lymphoma (MCL) treated with the agent after just one prior line of therapy, according to pooled long-term follow-up data presented at the annual meeting of the American Society of Hematology.
With a 3.5-year median follow-up, a median PFS of 33.6 months was reported for MCL patients with one prior line of therapy, compared to 8.4 months for patients who had two or more prior lines of therapy, reported lead study author Simon Rule, MD, of Plymouth (England) University Medical School.
“I think the take-home message from the ibrutinib data is the earlier you use the drug in the relapse setting, the better the outcomes you’re going to get,” Dr. Rule said in an interview. “It is quite dramatic, the difference between one prior line of therapy and subsequent lines of therapy.”
Response rates were also higher in MCL patients who had only one prior line of therapy, Dr. Rule said.
The overall and complete response rates for that group were 77.8% and 36.4%, respectively, according to data Dr. Rule presented in an oral presentation. For patients receiving more than one line of therapy prior to ibrutinib, overall and complete response rates were 66.8% and 22.9%.
The pooled analysis presented by Dr. Rule included 370 patients enrolled in ibrutinib trials between 2011 and 2013. Patients in those trials received oral ibrutinib 560 mg daily until progressive disease or unacceptable toxicity.
Patients achieving a CR had an “extraordinary” PFS of nearly 4 years and a median duration of response of 55 months, Dr. Rule said.
Atrial fibrillation (AF) rates were reported to be 5.7% (21/370 patients). A total of 53 patients in the analysis had ongoing controlled AF/arrhythmia or had a history of it. Over the course of follow-up, 70% of them (37 patients) had no recurrences, according to Dr. Rule and his colleagues.
No patients discontinued ibrutinib because of grade 3-4 AF, they reported. Moreover, less than 2% of the 370 patients discontinued or reduced dose of ibrutinib because of grade 3-4 bleeding or AF.
New onset grade 3-4 adverse events were more common in the first year of treatment and generally were less frequent over time, Dr. Rule said.
Patients with only one prior line of therapy were less likely to have grade 3-4 adverse events, suggesting again that “the earlier you use [ibrutinib], the fewer side effects you get, particularly with hematologic toxicity,” Dr. Rule said.
Sponsorship for the research came from Janssen, and funding for writing assistance came from Janssen Global Services. Dr. Rule reported financial relationships with Janssen and several other companies.
SOURCE: Rule S et al. ASH 2017 Abstract 151.