Pathways and mechanisms of venetoclax resistance

Abstract

The approval of venetoclax, a ‘BH3-mimetic’ antagonist of the BCL-2 anti-apoptotic protein, for chronic lymphocytic leukemia represents a major milestone in translational apoptosis research. Venetoclax has already received ‘breakthrough’ designation for acute myeloid leukemia, and is being studied in many other tumor types. However, resistance to BCL-2 inhibitor monotherapy may rapidly ensue. Several studies have shown that the other two major anti-apoptotic BCL-2 family proteins, BCL-X_L and MCL-1, are the main determinants of resistance to venetoclax. This opens up possibilities for rationally combining venetoclax with other targeted agents to circumvent resistance. Here, we summarize the most promising combinations, and highlight those already in clinical trials. There is also increasing recognition that different tumors display different degrees of addiction to individual BCL-2 family proteins, and of the need to refine current ‘BH3 profiling’ techniques. Finally, the successful clinical development of potent and selective antagonists of BCL-X_L and MCL-1 is eagerly awaited.

Keywords:

• Venetoclax
• resistance
• BCL-2
• MCL-1
• BCL-XL
• rational combinations

Acknowledgements

This work was supported in part by the MD Anderson Cancer Center Support Grant P30 CA016672 from the National Institutes of Health. The authors thank Pankit Vachhani, M.D., Roswell Park Cancer Institute, Buffalo, NY, for his assistance with preparing the figure.

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article online at http://dx.doi.org/10.1080/10428194.2017.1283032.