Study: New FDA approval of Itovebi, a drug that may improve treatment for certain advanced or metastatic breast cancers

RELEVANCE

Most relevant for: People with advanced or metastatic breast cancer with a PIK3CA tumor mutation..

It may also be relevant for:

• people with breast cancer
• people with ER/PR + cancer
• people with metastatic or advanced cancer

Relevance: High

Strength of Science: High

Research Timeline: Post Approval

More rating details

What is this study about?

A research study named INAVO120 looked at the safety and effectiveness of Itovebi (inavolisib), a new drug for treating hormone receptor-positive (HR-positive), HER2-negative advanced or metastatic breast cancer with a PIK3CA tumor mutation.

Why is this study important?

About 35-40% of people with HR-positive metastatic breast cancer have a tumor marker called a PIK3CA mutation. People who have these cancers usually receive hormone therapy, such as Faslodex, and a CDK4/6 inhibitor, such as Ibrance. However, some cancers become resistant and progress (get worse over time). Researchers are looking at new drugs to help keep the metastatic breast cancer from progressing.

In this study, researchers looked at whether Itovebi, a targeted therapy known as a PI3K inhibitor, plus standard-of-care treatment improved patients’ outcomes compared to those receiving standard-of-care only.

The positive results of the INAVO120 study led to FDA approval of a new treatment: using Itovebi in combination with Ibrance and Faslodex for people with advanced or metastatic breast cancer that:

• is hormone receptor-positive (HR-positive)
• is HER2-negative
• has a specific PIK3CA tumor mutation
• has progressed during or after hormone therapy
   

This combined treatment is given as a pill. To determine if a person is eligible for this treatment, doctors can use a special FDA-approved blood test called FoundationOne Liquid CDx to check for the PIK3CA mutation.

Study findings

The INAVO120 trial enrolled 325 people who had HR-positive, HER2-negative breast cancer that had recurred or grown within 12 months of hormone therapy. All participants had a PIK3CA tumor mutation.

Participants were randomly chosen to receive one of the following treatments:

• Itovebi combined therapy: Standard therapy with Ibrance and Faslodex plus Itovebi (161 people)
• Standard therapy: Standard therapy with Ibrance and Faslodex plus a placebo (a non-active ingredient) (164 people)

People with PIK3CA tumor mutations treated with a combination of Itovebi plus standard treatment with Ibrance and Faslodex lived longer without their cancer progressing, and their tumors shrank more compared to those treated with standard treatment only. 

Side Effects

Although several side effects occurred with Itovebi, most were manageable. Although serious to severe instances of low white blood cell counts occurred in most patients treated with Itovebi, these were all resolved with medical care, and no treatment-related deaths occurred. Side effects led 7% of participants in the Itovebi group to discontinue treatment compared to 0.6% among the placebo group.

What does this mean for me?

Results from this study show that adding Itovebi (inavolisib) to standard therapy significantly prolongs life and leads to tumor shrinkage compared to those who only received standard therapy.

If you have HR-positive, HER2-negative advanced or metastatic breast cancer with a PIK3CA tumor mutation, Itovebi combined therapy may be an option for treatment after hormone therapy. If you have HR-positive, HER2-negative breast cancer, ask your healthcare provider if your tumor has a PIK3CA mutation or whether you should consider having tumor testing for a PIK3CA mutation.

While side effects were common among people treated with Itovebi, particularly low white blood cell counts, they were generally treatable and resolved with medical care. If you take Itovebi, discuss with your healthcare team which symptoms to watch for and how you will be monitored during your treatment.

Reference

Jhaveri KL, Im SA, Saura C et al. Overall Survival with Inavolisib in PIK3CA-Mutated Advanced Breast Cancer. New England Journal of Medicine 2025 May 31. doi: 10.1056/NEJMoa2501796.

U.S. Food and Drug Administration. FDA approves inavolisib with palbociclib and fulvestrant for endocrine-resistant, PIK3CA-mutated, HR-positive, HER2-negative, advanced breast cancer. FDA. Published October 10, 2024. Accessed May 23, 2025.

Disclosure: FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to ensure scientific integrity.

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posted 7/3/25