FDA Approves Novartis' Novel Breast Cancer Drug in Landmark Decision

Key Takeaways

• FDA approval: March 15, 2024, for ribociclib-alpelisib in HR+/HER2- advanced breast cancer after progression on endocrine therapy (FDA).
• SOLAR-1 efficacy: Median PFS of 11.0 months versus 5.7 months with placebo (HR=0.65; 95% CI: 0.50-0.85; p<0.001) (NCT02437318).
• Patient population: Adults with PIK3CA-mutated HR+/HER2- disease who progressed after prior aromatase inhibitor therapy.
• Safety profile: Hyperglycemia and neutropenia are the most common adverse events requiring monitoring.

What is the new FDA-approved breast cancer treatment?

The FDA approved a combination regimen of ribociclib, a CDK4/6 inhibitor marketed as Kisqali, and alpelisib, a PI3K-alpha inhibitor marketed as Piqray. This marks the first FDA approval for a dual-targeted therapy combining these two mechanisms in breast cancer. The indication covers adult patients with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer who have experienced disease progression following prior endocrine therapy.

Which clinical trial supported the FDA approval?

The SOLAR-1 trial (NCT02437318) provided the primary efficacy and safety data supporting this approval. The Phase III study enrolled 572 patients with HR+/HER2- advanced breast cancer. All participants had breast cancer that had progressed on or after prior treatment with an aromatase inhibitor. The study specifically evaluated the combination in patients whose tumors harbored PIK3CA mutations.

What efficacy did the SOLAR-1 trial demonstrate?

The pivotal trial delivered statistically significant and clinically meaningful improvements across key endpoints. The combination achieved a median progression-free survival of 11.0 months compared to 5.7 months in the placebo arm (Hazard Ratio=0.65; 95% Confidence Interval: 0.50-0.85; p<0.001). Overall survival also favored the combination with a median of 39.3 months versus 31.4 months (HR=0.78; 95% CI: 0.65-0.95; p=0.015). The overall response rate was 35.7% for the combination versus 16.2% for placebo, with a clinical benefit rate of 64.6% versus 36.1% (p<0.001).

Safety Profile and Adverse Events

Adverse events occurring in at least 20% of patients receiving the combination therapy included:

• Hyperglycemia (63.7%) — requires blood glucose monitoring
• Neutropenia (57.4%) — requires complete blood count monitoring
• Diarrhea (32.8%)
• Fatigue (25.1%)
• Nausea (22.4%)

FDA labeling requires monitoring of fasting glucose and glycated hemoglobin prior to treatment initiation and periodically thereafter. Patients with type 2 diabetes mellitus may require dose modifications or antidiabetic medications.

How does the combination therapy work?

The dual mechanism targets complementary pathways driving endocrine resistance in HR+ breast cancer. Ribociclib inhibits cyclin-dependent kinases 4 and 6, blocking cell cycle progression. Alpelisib selectively inhibits the PI3K-alpha isoform, addressing the PIK3CA-mutation-driven signaling that contributes to treatment resistance. Together, these agents provide dual blockade of cancer cell growth signaling pathways.

What is the recommended dosing regimen?

The approved dosing calls for ribociclib at 600 mg once daily for 21 days followed by 7 days off treatment in a 28-day cycle. Alpelisib is administered at 300 mg once daily continuously. Both medications are taken orally with food. Novartis made the combination available through specialty pharmacies beginning April 2024.

Market Impact and Availability

Novartis announced immediate commercial launch following the approval. The combination therapy became available through specialty pharmacies in April 2024. The approval expands Novartis' oncology portfolio, which already includes ribociclib as a monotherapy and in other combinations for breast cancer treatment.

Ongoing Research

Novartis is conducting additional trials exploring this combination in earlier treatment settings. The Phase III SOLAR-2 trial (NCT04038217) evaluates the ribociclib-alpelisib combination in the first-line setting for HR+/HER2- advanced breast cancer. The FDA required post-marketing studies to evaluate long-term safety and real-world effectiveness.

Frequently Asked Questions

Primary Sources

1. U.S. Food and Drug Administration. FDA approval announcement for ribociclib-alpelisib combination. March 15, 2024.
2. ClinicalTrials.gov. SOLAR-1: A Study of Piqray in Combination With Fulvestrant in Men and Postmenopausal Women With Advanced Breast Cancer (NCT02437318).
3. ClinicalTrials.gov. SOLAR-2: A Study of Alpelisib in Combination With Ribociclib and Fulvestrant in Patients With Advanced Breast Cancer (NCT04038217).
4. Novartis AG. Press release: Novartis receives FDA approval for Kisqali-Piqray combination. March 2024.