FDA Grants Priority Review to Inavolisib for Advanced Hormone Receptor-Positive HER2-Negative Breast Cancer

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Genentech announced that the FDA has granted Priority Review to its New Drug Application (NDA) for inavolisib, an investigational oral therapy under evaluation to treat advanced hormone receptor-positive, HER2-negative breast cancer with a PIK3CA mutation. According to the company, the Priority Review status is based on promising results from the Phase III INAVO120 clinical trial (NCT04191499), which found that inavolisib in combination with Ibrance (palbociclib) and Faslodex (fulvestrant) extended progression-free survival (PFS) compared to standard treatments. The FDA assigned the NDA with a Prescription Drug User Fee Act date of November 27, 2024.¹

“The addition of inavolisib to standard of care treatment significantly delayed disease progression in the first-line setting and has the potential to extend survival for people with metastatic breast cancers that harbor PIK3CA mutations,” said Levi Garraway, MD, PhD, chief medical officer, head of global product development, Genentech, in a press release. “We welcome the FDA’s Priority Review designation for inavolisib, which underscores the urgency to bring this potential best-in-class treatment option to patients as quickly as possible.”

Last week, the FDA granted Breakthrough Therapy Designation (BTD) to inavolisib based on positive results from the INAVO120 trial.

The randomized, double-blind, placebo-controlled trial randomly assigned 325 patients to either the investigational cohort, in which they were administered inavolisib with Ibrance and Faslodex, or a control treatment arm in which they were administered Ibrance and Faslodex alone. The trial’s primary endpoint was PFS as assessed by investigators, with secondary endpoints that included overall survival (OS), objective response rate, and clinical benefit rate.

Patients in the inavolisib cohort achieved an increased PFS of 57% compared to palbociclib and fulvestrant alone at 15.0 months vs. 7.3 months, respectively (hazard ratio [HR]=0.43, 95% CI: 0.32-0.59, p<0.0001). Currently, OS data are in the process of being determined.²

“We are pleased that the FDA granted Breakthrough Therapy Designation for inavolisib in recognition of the substantial clinical benefit observed with this regimen,” said Garraway, in a press release. “This promising inavolisib-based regimen could transform the PI3K inhibitor class, potentially becoming the standard of care for this patient population in the first-line setting.”

According to Healthline, 81% of new female breast cancer cases between 2017 and 2021 wereHER2-negative. The disease results from breast cancer cells not maintaining a high level of HER2 proteins. It is much more common than HER2-positive breast cancer and spreads at a much lower rate. Additionally, targeted therapies aren’t typically implemented in the treatment of HER2-negative breast cancer. Current treatments include chemotherapy, Keytruda (pembrolizumab), PARP inhibitors, and medications such as tamoxifen and abemaciclib.³

“HER2-negative breast cancer is a type of breast cancer that accounts for about 78% of all breast cancer cases.1 Its name describes the status of the human epidermal growth factor receptor 2, known as HER2, in the disease,” reports Verywell Health. “Not all breast cancer cases are the same. Testing for the HER2 protein helps define key aspects of your illness that affect the type of treatment you receive. HER2 is a protein that exists on the surface of all breast cells. It supports normal cell growth and repair. Very high levels of HER2 can lead to HER2-positive breast cancer. Breast cells in HER2-negative breast cancer have little HER2 protein.”⁴

References

1. FDA Grants Priority Review to Genentech’s Inavolisib for Advanced Hormone Receptor-Positive, HER2-Negative Breast Cancer With a PIK3CA Mutation. Genentech. May 28, 2024. Accessed May 29, 2024. https://www.gene.com/media/press-releases/15026/2024-05-28/fda-grants-priority-review-to-genentechs

2. FDA Grants Breakthrough Therapy Designation to Genentech’s Inavolisib for Advanced Hormone Receptor-Positive, HER2-Negative Breast Cancer With a PIK3CA Mutation. Genentech. May 20, 2024. Accessed May 29, 2024. https://www.gene.com/media/press-releases/15025/2024-05-20/fda-grants-breakthrough-therapy-designat

3. What’s the Difference Between HER2-Negative and HER2-Positive Breast Cancer? Healthline. Accessed May 29, 2024. https://www.healthline.com/health/breast-cancer/her2-positive-vs-her2-negative

4. What Is HER2-Negative Breast Cancer? VeryWellHealth. October 18, 2022. Accessed May 29, 2024. https://www.verywellhealth.com/her2-negative-breast-cancer-6661316