Poor clinical outcomes were noted in the majority of patients with primary or secondary ibrutinib resistance, according to a study of 114 patients with mantle cell lymphoma who experienced disease progression while receiving ibrutinib. Researchers found:

• Median number of prior therapies was 3.

• MIPI scores at start of ibruninib were low, intermediate, and high in 46%, 31%, and 23% of patients, respectively.

• 34 of 47 patients had Ki67>30% before ibrutinib.

• 11/12 patients had Ki67>30% after ibrutinib.

• Median time on ibrutinib was 4.7 months.

• Median overall survival (OS) following cessation of ibrutinib was 2.9 months.

• Of 104 patients with available data, 73 underwent subsequent treatment an average of 0.3 months after stopping ibrutinib with a median OS of 5.8 months.

• Multivariate analysis of MIPI prior to post-ibrutinib treatment, and subsequent treatment with bendamustine, cytarabine, or lenalidomide failed to show any association with OS.

Citation: Martin P, Maddocks K, Leonard JP, et al. Post-ibrutinib outcomes in patients with mantle cell lymphoma. [Published online ahead of print January 13, 2016]. Blood. doi: 10.1182/blood-2015-10-673145.