By John Allan M.D.
The survival of tumor cells is dependent on the tumor cells maintaining a normal interaction with the healthy microenvironment. An increasingly important strategy in the treatment of CLL is to develop new therapies that do not necessarily attack the cancerous cells themselves, but instead attack the molecular processes that allow the cancerous cells to function and thrive in the microenvironment. One potential target for treating CLL is the protein complex NF-kB, which controls important cell functions including the regulation of cell death, cell survival, and cell proliferation. If NF- kB function can be inhibited then CLL can be more easily treated.
The purpose of this recent study presented at the 2016 ASH meeting was to test the efficacy of the newly developed NF-bK inhibitor IT901 in the treatment of CLL and its aggressive transformation Richter’s Syndrome (RS). RS is a transformation that occurs within 5-10% of CLL’s and turns the disease into a fast growing diffuse large B-cell lymphoma, an aggressive non-Hodgkin lymphoma. The treatment of RS currently represents an unmet therapeutic need.
Results from this study were confirmed in a mouse xenograft model for people with CLL and in cell samples obtained from people with RS. In both models the use of IT901 was characterized by decrease in tumor growth and Researchers found that IT901 induced death in cancerous cells within 24 hours of treatment with a minimal impact on normal B-cells.
Researchers concluded that IT901 is effective in rapidly blocking NF-kB activity by decreasing the functions that allow the cell to flourish in the microenvironment. The results from this study are encouraging and point to a potential new treatment option for patients with CLL and RS.
By Richard Furman, M.D.
Patients with CLL who relapse after or become refractory to treatments like ibrutinib or idelalisib have poor outcomes. Venetoclax (also known as ABT-199) is an oral inhibitor of the BCL-2 (B-cell lymphoma 2) protein. The BCL-2 protein plays a critical role in preventing cells from undergoing apoptosis (cell death), in healthy cells and in CLL cells. In a recent study presented at the 2016 annual ASH meeting, we evaluated the effectiveness of venetoclax in treating people who relapsed after or were refractory to ibrutinib or idelalisib.
During this phase 2 trial 64 people with CLL were divided into two arms. The first arm consisted of those who were relapsed or refractory to ibrutinib, while the second arm included those who were relapsed or refractory to idelalisib. 43 patients were enrolled in the first arm and were on ibrutinib for a median of 17 months, receiving venetoclax for a median of 13 months, while 21 patients in the second arm were on idelalisib for a median of 8 months and received venetoclax for a median of 9 months. Thirty-nine patients in the ibrutinib arm and 21 patients in idelalisib arm completed the full course of treatment. The objective response rate as determined by investigators was 69% (27/39) for people who were ibrutinib resistant, and 57% (12/21) for the idelalisib resistant. At the time of analysis no median progression free survival or overall survival has been reached. Overall the progression free survival was 72% and overall survival was 90% for all participants.
The results from this trial demonstrate that venetoclax has displayed robust activity and is tolerable for people whose CLL has progressed after treatment with ibrutinib and idelalisib. Although there have been few complete responses, patients will continue to be monitored to chart any further improvements. Additional follow up will be required to assess how long lasting venetoclax responses will be.
In an interview with MDLinx during the 2016 American Society of Hematology Annual Meeting, Dr. Peter Martin discusses results from a phase I clinical trial designed to evaluate the safety and activity of ibrutinib plus palbociclib in people with previously treated MCL.