Typically, the longer a patient with cancer is exposed to a drug the more side effects they experience, but in the case of Imbruvica, the opposite appears to be true for patients with MCL.
Contrary to what is sometimes seen with chemotherapy, research being presented at the 2019 American Society of Hematology (ASH) Annual Meeting has found that BTK inhibitors such as Imbruvica (ibrutinib) could provide better responses in patients with mantle cell lymphoma (MCL), even after more than seven years of treatment.
Typically, patients experience greater side effects the longer they are exposed to a drug, but according to Dr. Simon Rule, a professor of hematology at Plymouth University, many patients saw no new toxicities with extended use of Imbruvica.
What we did was just a further follow up on a group of patients that we’ve been looking at for a while now. It’s three trials of patients receiving single-agent ibrutinib, and basically, it’s just long-term follow up to see whether with longer exposure to a drug, you’re developing side effects or whether the efficacy is still there. It’s basically an additional safety analysis.
What we found was that a portion of patients still remain on the drug, with a seven-and-a-half-year follow up, and there’s no emergence of new toxicity, which is very encouraging. But perhaps the most important bit of the analysis was, for the first time, we looked at how response to ibrutinib compared with prior therapies.
With MCL, when you use chemotherapy, each time you use a different chemotherapy, you get less of a response. This is a common thing you see with lymphomas. But with MCL, when you use ibrutinib, what we find is that the ibrutinib response is generally better than the prior chemotherapy. In one group, it’s spectacularly better, and that’s the patients that get the most benefit from the chemotherapy.
So that’s the group where people would be more inclined to use chemotherapy again, but actually that group gets the most benefit (from ibrutinib). In fact, the average benefit is more than a year from the second therapy compared with the first. This is against what one normally finds with chemotherapy. So, it just further encourages the use of these drugs earlier in the treatment paradigm.