Imbruvica treatment in patients with chronic lymphocytic leukemia whose disease expressed a certain mutation elicited sustained efficacy over a median follow-up of four years, according to data from a long-term analysis.
Data from a long-term analysis of four studies at four years of follow-up demonstrated that
Imbruvica (ibrutinib) was significantly effective in patients with chronic lymphocytic leukemia (CLL) whose disease harbored certain mutations.
Dr. John Allan, assistant professor of medicine at Weill Cornell Medicine, presented data at the ASH Annual Meeting and Exposition demonstrating how Imbruvica was effective in a wider patient population. In an interview with CURE®, Allan discussed the overall make-up of the study and what the results mean for the patient population.
One was a phase 2 study from the NCI looking at 17p deleted patients treated with frontline ibrutinib (Imbruvica), and this is where most of our data previously had come from and was extrapolated from looking at those 34 patients. The other three studies that were included were reported phase 3 studies: RESONATE2, ILLUMINATE and the ECOG1912 study. From those four pooled studies, we found 89 patients that had a 17p deletion or P53 mutation that were enrolled in those studies and then followed prospectively now long term. In those 89 patients, what we found is that the median age was 65 years old, 69% of them had an unmutated IGHV, 38% had bulky disease and of those 89 patients, all of them had FISH results available and 53% had a deletion 17p presence.
So, all of the other patients had mutations only, and of those patients that had sequencing available, only 58 of the 89 patients actually had those results available or performed. And what was interesting is that of those subjects, 91% of the patients who had sequencing performed were positive for the P53 mutation. When we look at 16 of the patients who had both FISH and sequencing results done, and what we found was that 11, or about 70% of patients had both a 17p deletion and a p53 mutation. So, this is the cohort that we studied long term, these 89 patients, and these patients were followed for a median of 15 months. What we found basically as the efficacy in these patients is that at the four-year mark, the progression free survival at that mark was 79% and the four-year overall survival was at 88%. So, patients were doing very, very well.
One thing that we noted is that reasons for discontinuation, were a little bit different than in previous reports, whereas, in this study 20% of patients discontinued ibrutinib due to progressive disease, whereas in previous reports, it seemed to be more commonly due to side effects and true progressions on drug were relatively rare. This kind of still highlights the fact that these very high-risk patients, while they seem to be doing really well, and some of this high-risk feature may have been overcome by ibrutinib use, they still potentially are at risk for failure of these drugs and we need to better understand why, and which patients are the ones that are truly failing.
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