Henrik Grönberg, MD

Formal discussant of the -IPATential150 trial, Henrik Grönberg, MD, Professor at Karolinska Institute, Stockholm, found the study results intriguing, especially in the PTEN-loss patients. “Biomarkers are the wave of the future,” he said.

“The study population was compared with an adequately treated control group. It is interesting that only about 18% of patients had prior taxane-based therapy, which is less than we see in clinical practice. With only a 2.6-month difference in radiographic progression–free survival in the overall trial, the primary endpoint of IPATential150 was not met,” Dr. Grönberg told listeners. “However, in the immunohistochemistry-defined PTEN-loss group, the 2-month difference met the primary endpoint.”

“The subgroup data suggest that prior taxanes may make patients less responsive to AKT inhibitors. We need to delve further into this,” he continued.

“To me, the most interesting slide is on radiographic progression–free survival in the next-generation sequencing–defined PTEN-loss population. The definition of biomarkers is very important, and I believe that next-generation sequencing is a better way to define PTEN-loss than immunohistochemistry,” he said. “Going forward, I think we should study biomarkers prospectively and use the best method to evaluate them (ie, next-generation sequencing and liquid biopsy).”

Dr. Grönberg said that he would not change his practice based on this study. “The data are promising in the next-generation sequencing–defined group [of PTEN loss], but it is too early to change practice. We still need to better define the subgroups that benefit, and we need more mature data from IPATential,” he said. 

Publisher's Note: This article was originally published in the October 25, 2020 issue of The ASCO Post.

DISCLOSURE: Dr. Grönberg has received honoraria from Astellas Pharma, Bristol Myers Squibb, and Janssen Oncology and holds five pending patents related to the diagnosis of prostate cancer.