Immunotherapy Combo Effective Against Rare Non-Hodgkin Lymphoma

Ibrutinib (Imbruvica) plus rituximab increased progression-free survival among patients with Waldenström's macroglobulinemia.

AbbVie recently announced positive results from a phase 3 clinical trial investigating ibrutinib (Imbruvica) plus rituximab in patients with Waldenström's macroglobulinemia (WM), a rare non-Hodgkin lymphoma. Only 1000 to 1500 patients are diagnosed with WM each year, according to a press release.

The researchers discovered that the investigational combination therapy was effective in both treatment-naïve and previously-treated patients with WM.

The combination of ibrutinib plus rituximab met its primary endpoint of progression-free survival (PFS) compared with rituximab monotherapy, according to the release.

"Imbruvica is the first and only treatment approved in Waldenström's macroglobulinemia. We continue to be committed to exploring the full potential of IMBRUVICA, and are pleased to add the results of iNNOVATE to our growing scientific understanding of its use as a combination therapy in WM and other blood cancers," said Thorsten Graef, MD, PhD, head of Clinical Development at Pharmacyclics LLC, an AbbVie company.

Included in the iNNOVATE clinical trial were 150 patients with relapsed/refractory and treatment-naïve WM. Patients were randomized to receive intravenous rituximab 375-mg/m2 once per week for 4 weeks, followed by another 4 weeks of weekly rituximab after a 3-month interval. Patients also received daily ibrutinib 420-mg or placebo.

The primary endpoint was PFS, with overall response rate, hematological improvement, time-to-next treatment, overall survival, and number of participants with adverse events as secondary endpoints, according to the release.

AbbVie said they plan to share these positive findings with regulatory agencies.

Ibrutinib is a first-in-class Bruton’s tyrosine kinase inhibitor that was previously granted Breakthrough Therapy designation and was approved to treat WM in 2015, according to the release.

Ibrutinib is also approved to treat chronic lymphocytic leukemia, small lymphocytic lymphoma and previously-treated mantle cell lymphoma, marginal zone lymphoma, and chronic graft-versus-host disease.

"This is a first-of-its-kind prospective randomized trial in Waldenström's macroglobulinemia," said Meletios A. Dimopoulos, MD, professor and chairman of the Department of Clinical Therapeutics at the National and Kapodistrian University of Athens School of Medicine. "The full report of this study will be of important clinical significance regarding the benefits of the combination of ibrutinib with rituximab in patients with WM."