ONCAlert | 2017 San Antonio Breast Cancer Symposium
Chronic Lymphocytic Leukemia Case Studies

Paul Barr, MD: Use of Bruton's Tyrosine Kinase Inhibitor

Paul Barr, MD
Published Online:Nov 02, 2015
Robert C is a 63-year-old retired civil engineer from Houston, Texas with a medical history notable for acute appendicitis and appendectomy.

Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 1

Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 1
Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 2
Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 1
Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 2
Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 1
Relapsed and Refractory CLL with Javier Pinilla-lbarz, MD, PhD and Paul Barr, MD: Case 2

 

 

What phase III data support the use of a Bruton's tyrosine kinase inhibitor in this patient?

 

The best phase III data supporting the use of the BTK inhibitor in a patient with deletion 17p comes from the Resonate study,  a randomized  trial enrolling patients with relapsed or refractory CLL [who] were either treated with ibrutinib 420 mg once daily until progression, or a typical 20-week, 24-week, course of ofatumumab, an anti-CD20 antibody.

 

 Importantly, of the patient population enrolled in this study, a third had deletion of 17p, and interestingly, about half had a mutation in the TP53 gene.  It really was a group of patients that [had] high-risk factors, those having TP53 dysfunction.

 

With this in mind, ibrutinib provided a statistically superior PFS compared with ofatumumab. And in   the recently presented 18-month follow-up data, we saw a PFS for ibrutinib of about 76% compared with about 8%  for ofatumumab. In addition, we saw an overall survival (OS) benefit in this patient population, suggesting the benefit of ibrutinib in patients with poor risk factors.

 

It’s important to mention two other data sets. These are phase II, single-arm investigations where the patients were treated with ibrutinib, but focused on patients with deletion 17p. One was a multicenter study only enrolling patients with deletion 17p, referred to as the Resonate 17 study. The second data set comes from the National Institutes of Health (NIH) led by Adrian Weisner.  Those studies taught us that ibrutinib can work exceptionally well in patients with deletion 17p. And in about 1 year of follow-up we see the PFS of about 80%.

 

When you compare this to historical results using chemoimmunotherapy, where we see a duration of response in less than a year, only a few months in some cases, to see 80% of patients [with] PFS of 1 year really looks like an improvement.

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