What Patients With Breast Cancer Need to Know About Itovebi

Itovebi, approved for some patients with breast cancer, is the first PI3K inhibitor to display a survival benefit, according to Dr. Kevin Kalinsky: © Konstanin Yuganov - stock.adobe.com.

As part of his talk during the CURE Educated Patient Breast Cancer Summit held during the 42^nd Annual Miami Breast Cancer Conference, Dr. Kevin Kalinsky discussed the U.S. Food and Drug Administration (FDA) approval of Itovebi (inavolisib) with Ibrance (palbociclib) and Faslodex (fulvestrant) for some patients with advanced or metastatic breast cancer.

Kalinsky is a professor and director in the Division of Medical Oncology of the Department of Hematology and Medical Oncology at Emory University School of Medicine, in Atlanta, Georgia. He also serves as the director of the Glenn Family Breast Center and the Louisa and Rand Glenn Family Chair in Breast Cancer Research at Winship Cancer Institute of Emory University. During his talk at the CURE Summit, he discussed hormone receptor (HR)-positive breast cancer.

“This drug, [Itovebi], is approved in a very specific situation; it is approved in patients who have early-stage breast cancer,” said Kalinsky. “They are taking their endocrine therapy, whatever that [may be], like tamoxifen or an aromatase inhibitor, and their tumor becomes metastatic, either while taking that endocrine therapy or within 12 months of completing that endocrine therapy; it's [administered in] a very endocrine resistant sort of [population].”

The Itovebi combination regimen was approved in October 2024 for the treatment of adult patients with endocrine-resistant, PIK3CA-mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer.

The approval was based on the findings of the INAVO120 trial, which included 325 patients with endocrine-resistant, PIK3CA-mutated HR-positive, HER2-negative locally advanced or metastatic breast cancer who experienced disease progression during or within 12 months of completing adjuvant endocrine therapy and who had not received prior systemic therapy for locally advanced or metastatic disease.

Learn more: What Patients With Breast Cancer Need to Know About Itovebi and Blood Sugar

The median progression-free survival was 15 months in the Itovebi group and 7.3 months in the trial’s placebo group. The objective response rate was 58% in the Itovebi group and 25% in the placebo arm. The median duration of response was 18.4 months in the Itovebi group and 9.6 months in the placebo group.

Itovebi, according to the National Cancer Institute, works by blocking the activity of the PI3K-alpha protein that signals cancer cells to multiply, and also breaks down mutant versions of the protein found in some cancer cells, which may prevent cancer cells from growing and may kill them.

“From our standpoint, three drugs can be a lot to take, right? But it [showed] such impressive activity in patients who got [Faslodex] and [Ibrance] compared with those who were getting the triplet,” said Kalinsky. “There were some patients who had some immediate tumor progression while starting just [Faslodex] and [Ibrance], but that's not seen with the triplet.”

Itovebi manufacturer Roche announced in January that the triplet regimen was also associated with positive overall survival results in the INAVO120 study; this, in turn, led to the trial meeting its key secondary endpoint of a statistically significant and clinically meaningful overall survival benefit versus Ibrance and Faslodex alone. The announcement stated that the regimen reached statistical significance by more than doubling progression-free survival in patients, with no new safety signals observed.

“There was a press release that just came out recently that showed that patients live longer with this triplet, and this is the first time that we've seen a survival benefit for patients getting a PI3K inhibitor. We haven't seen those data yet. We don't know the extent of that improvement in survival, but this is the first time that has been seen with this class.”

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