Long-Term Data Offers Positive Findings for Imbruvica

Long-term data from the phase 3 RESONATE clinical trial have showed continued survival rates for patients with leukemia treated with ibrutinib (Imbruvica) up to 4 years, according to a presentation at the Annual Meeting of the American Society of Clinical Oncology (ASCO).

These findings reinforce the safety and efficacy of ibrutinib among patients with relapsed/refractory (R/R) chronic lymphocytic leukemia/ small lymphocytic leukemia (CLL/SLL), according to a press release.

The investigators discovered that treatment with ibrutinib was linked to a longer progression free survival in 59% in patients with R/R CLL/SLL compared with patients treated with ofatumumab (Arzerra). These results remained true in subgroups of patients with genetic susceptibility to poor outcomes.

The researchers also found that 74% of patients treated with ibrutinib achieved 3-year overall survival and 91% of patients achieved an overall response rate, with the complete response rate increasing over time, according to the study.

"These results suggest ibrutinib continues to provide persistent responses over the long-term in patients with chronic lymphocytic leukemia, including those who are difficult to treat," said lead investigator John C. Byrd, MD. "As a clinician who has treated patients with CLL for more than 20 years, I'm pleased to see the potential for efficacy and safety responses to continue over an extended period of time."

CLL is a common form of leukemia occurring in adults. The cancer begins in the lymphocytes in bone marrow, which then spread to the blood. SLL also affects the lymphocytes, but differs in where the cancer primarily occurs, according to the study.

Ibrutinib is a Bruton’s tyrosine kinase (BTK) inhibitor. BTK is a molecule that plays a role in the proliferation of cancerous B cells. Ibrutinib works by blocking signaling that tells the cancerous cells to spread.

The drug has received 5 FDA approvals thus far in patients with CLL, SLL, Waldenström's macroglobulinemia, previously-treated mantle cell lymphoma, and previously-treated marginal zone lymphoma, according to AbbVie.

Since its approval in 2014, more than 25,000 patients with CLL have received treatment with ibrutinib.

These long-term findings suggest that ibrutinib can extend survival among patients with CLL/SLL, leading to optimal outcomes.

"The first pivotal RESONATE data on Imbruvica were presented 3 years ago at ASCO and represented the promise of a new standard of care in blood cancer treatment. We are pleased to continue to see very favorable responses and survival outcomes to Imbruvica in relapsed and refractory CLL patients now into the fourth year of study," said Danelle James, MD, MS, head of Clinical Science, Pharmacyclics LLC, an AbbVie company. "We believe in the potential of Imbruvica across a range of blood cancers and other serious diseases, and are continuing to explore its potential as part of our robust clinical research program."