In May 2015, the Federal Drug Administration (FDA) granted venetoclax a breakthrough therapy designation for treating patients with relapsed or refractory chronic lymphocytic leukemia (CLL) with a specific genetic alteration – the 17p deletion. A second FDA breakthrough therapy designation was granted to venetoclax earlier this month for use in combination with rituximab (Rituxan) to treat patients with relapsed/refractory CLL. Last week, the FDA announced that they are granting “Priority Review” to venetoclax. This means that the treatment has been shown to be so effective compared to standard treatment options that the FDA is committed to allocating significant resources to further evaluate it. The label of Priority Review can be of great help in getting new, promising treatment options to more people as quickly as possible.
What is venetoclax?
Venetoclax (also known as ABT-199) is an oral inhibitor of the bcl-2 (B-cell lymphoma 2) protein. BCL-2 protein plays a critical role in preventing cells from undergoing apoptosis (cell death), including CLL cells.
Why did the FDA decide to grant Priority Review to venetoclax?
This Priority Review status is based upon results presented by investigators at the 2015 annual meeting of the American Society of Hematology (ASH) that took place in early December.
In this study, they found that of the 107 patients treated, 85 patients (79.4%) responded to treatment with venetoclax.
Of these patients who responded, eight patients (7.5%) experienced a complete response, meaning that no detectable levels of cancer remained. Three patients (2.8%) experienced nodular partial response (nPR), while 74 patients (69.2%) experienced partial response. Unlike a complete response a nPR includes some persistent remaining modules of lymphocytes. In the past it was difficult to differentiate these CLL cells from normal cells. However, we now know that patients with nPR do better than patients with partial responses, but not as well as complete responses.
Were there any side effects?
The side effect of primary concern based upon earlier studies was tumor lysis syndrome, which occurs when the CLL cells breakdown too rapidly and release too many of their breakdown products at one time, potentially causing kidney failure and death. Researchers sought to implement strategies to minimize the risk of tumor lysis. Other side effects were comparable or less prevalent than those experienced by people who received current standard chemotherapy treatment for CLL.
How can you access venetoclax now?
At Weill Cornell Medicine, we have a clinical trial with venetoclax already underway for relapsed/refractory CLL patients who have previously been treated with an inhibitor of the BCR signaling pathway, including idelalisib or ibrutinib. If you are interested in enrolling in or learning more about this clinical trial, please contact Amelyn Rodriguez RN, by email firstname.lastname@example.org or phone (212) 746-1362.