Advanced Breast Cancer Patients: FDA Fast-Tracks Inavolisib Combo

Introduction to Inavolisib and Its FDA Priority Review

The FDA has given a high-priority review to a new drug combination involving inavolisib for treating a specific type of advanced breast cancer. This is a major development for patients with hormone receptor-positive, HER2-negative breast cancer that carries a PIK3CA mutation.

The decision for the accelerated review was based on promising results from a phase 3 clinical trial named INAVO120. This trial tested the effectiveness and safety of inavolisib when combined with two other drugs, palbociclib and fulvestrant.

Details of the INAVO120 Clinical Trial

The INAVO120 trial included 325 patients with advanced breast cancer. These patients either received the combination of inavolisib, palbociclib, and fulvestrant or only palbociclib and fulvestrant. The main goal was to see how long the cancer would remain under control, known as progression-free survival (PFS).

The results were promising: patients who took inavolisib along with the other drugs experienced a longer period without cancer progression compared to those who didn't take inavolisib. Specifically, the median PFS for the inavolisib group was 15 months, compared to just 7.3 months for the other group.

Focus on Progression-Free Survival and Response Rates

The success of the treatment was measured in various ways. The primary focus was on PFS, but researchers also looked at overall survival (OS). While the OS data is still being evaluated, initial trends are positive for the inavolisib group.

Moreover, the objective response rate (ORR)—the percentage of patients whose cancer shrinks or disappears—was significantly higher in the inavolisib group. About 58.4% of patients experienced a positive response, compared to 25% in the group that didn’t receive inavolisib.

Combating Adverse Effects

Like most cancer treatments, the therapy had some side effects. Common issues included neutropenia (low white blood cell count), hyperglycemia (high blood sugar), and inflammation of the mouth or gut. While some side effects were more common in the inavolisib group, both groups experienced similar rates of neutropenia.

The Future of Inavolisib and Patient Outcomes

If approved, this combination treatment could become a new standard of care for patients with this type of advanced breast cancer. Experts believe that adding inavolisib can significantly delay the progression of the disease and potentially extend patients' lives.

In May 2024, the FDA had already granted breakthrough therapy designation to this drug combination, further emphasizing its potential clinical benefits.

Expert Opinions

Levi Garraway, MD, PhD, of Roche, commented on the significance of the FDA's priority review designation. He highlighted the urgency and potential benefits of bringing this treatment to patients quicker. According to Dr. Garraway, this combination could delay disease progression in the first line of treatment and extend patient survival.

Test Administration and Dosage

In practice, patients receiving this treatment took inavolisib at 9 mg daily along with palbociclib at 125 mg per day for 21 days, and fulvestrant at 500 mg administered periodically.

The trial's primary aim was to evaluate PFS based on what the investigators observed, while secondary goals included overall survival, response rate, and patient-reported outcomes.

Regulatory Timelines

The FDA has set a target date of November 27, 2024, to announce its final decision on the approval.

If granted, this combination will offer hope and potentially better outcomes for patients with advanced breast cancer that has specific genetic characteristics.