Genentech Announces Positive Phase III Results for Inavolisib Combination in People With Advanced Hormone Receptor-Positive, HER2-Negative Breast Cancer With a PIK3CA Mutation

December 5, 2023 |

4 min read

Genentech, a member of the Roche Group, announced positive results from the Phase III INAVO120 study of the investigational therapy, inavolisib, in combination with palbociclib and fulvestrant as a potential first-line treatment option for people with PIK3CA-mutated, hormone receptor -positive, HER2-negative, endocrine-resistant, locally advanced or metastatic breast cancer.

Phase III (INAVO120) results shows that inavolisib in combination with palbociclib and fulvestrant significantly improved progression-free survival in the first-line setting
PIK3CA mutations, found in approximately 40% of HR-positive breast cancers, are linked to tumor growth, disease progression, and treatment resistance
Data will be shared with health authorities and presented at an upcoming medical meeting

SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)-- Genentech, a member of the Roche Group (SIX: RO, ROG; OTCQX: RHHBY), announced today positive results from the Phase III INAVO120 study of the investigational therapy, inavolisib, in combination with palbociclib (Ibrance®) and fulvestrant as a potential first-line treatment option for people with PIK3CA-mutated, hormone receptor (HR)-positive, HER2-negative, endocrine-resistant, locally advanced or metastatic breast cancer. The study met its primary endpoint of progression-free survival (PFS), demonstrating a statistically significant and clinically meaningful improvement compared to palbociclib and fulvestrant alone. Overall survival data were immature at this time, but a clear positive trend has been observed. Follow-up will continue to the next analysis.

“These pivotal study results for this inavolisib combination represent a transformative medical advance for people with PIK3CA-mutated HR-positive breast cancer,” said Levi Garraway, M.D., Ph.D., Genentech’s chief medical officer and head of Global Product Development. “We are excited about the opportunity to expand our portfolio of breast cancer medicines into the HR-positive space and bring this potentially best-in-class new treatment option to patients as quickly as possible.”

The inavolisib combination was well tolerated and adverse events were consistent with the known safety profiles of the individual study treatments, with no new safety signals observed.

Inavolisib is an oral therapy with high in vitro potency and selectivity for PI3Kα inhibition and the ability to specifically trigger the breakdown of mutant PI3Kα protein. With this unique dual mechanism of action, inavolisib may provide well-tolerated, durable disease control and potentially improved outcomes for people with HR-positive/HER2-negative, PIK3CA-mutated advanced breast cancer. PIK3CA mutations can lead to mutated PI3Kα protein which contributes to uncontrolled tumor growth, disease progression and resistance to endocrine-based treatment.

Inavolisib is currently being investigated in three Phase III clinical studies in people with PIK3CA-mutated metastatic breast cancer (INAVO120, INAVO121, INAVO122) in various combinations.

About the INAVO120 Study

The INAVO120 study [NCT04191499] is a Phase III, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of inavolisib in combination with palbociclib and fulvestrant versus placebo plus palbociclib and fulvestrant in people with PIK3CA-mutated, hormone receptor (HR)-positive, HER2-negative, locally advanced or metastatic breast cancer whose disease progressed during treatment or within 12 months of completing adjuvant endocrine therapy and who have not received prior systemic therapy for metastatic disease.

The study included 325 patients, who were randomly assigned to either the investigational or control treatment arm. The primary endpoint is progression-free survival, as assessed by investigators, defined as the time from randomization in the clinical trial to the time when the disease progresses, or a patient dies from any cause. Secondary endpoints include overall survival, objective response rate, and clinical benefit rate.

About Hormone Receptor-Positive Breast Cancer

Hormone receptor (HR)-positive breast cancer is the most prevalent type of all breast cancers. A defining feature of HR-positive breast cancer is that its tumor cells have receptors that attach to one or both hormones – estrogen or progesterone – which can contribute to tumor growth. People diagnosed with HR-positive metastatic breast cancer often face the risk of disease progression and treatment side effects, creating a need for additional treatment options. The PI3K signaling pathway is commonly dysregulated in HR-positive breast cancer, often due to activating PIK3CA mutations, which have been identified as a potential mechanism for resistance to endocrine therapy and CDK4/6 inhibitors.

About Genentech in Breast Cancer

Genentech has been advancing breast cancer research for more than 30 years with the goal of helping as many people with the disease as possible. Our medicines, along with companion diagnostic tests, have substantially improved outcomes for HER2-positive breast cancer. As our understanding of breast cancer biology rapidly improves, we are working to identify new biomarkers and approaches to treatment for other subtypes of the disease, including estrogen receptor-positive breast cancer, which is a form of hormone receptor-positive breast cancer, the most prevalent type of all breast cancers.

About Genentech

Founded more than 40 years ago, Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes medicines to treat patients with serious and life-threatening medical conditions. The company, a member of the Roche Group, has headquarters in South San Francisco, California. For additional information about the company, please visit http://www.gene.com.

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