EU Approval Expands Treatment Scope

The European Commission (EC) approved Novartis' (NVS) Kisqali (ribociclib) on November 27, 2024, as adjuvant therapy for high-risk, HR-positive, HER2-negative early breast cancer. Kisqali selectively inhibits cyclin-dependent kinases 4 and 6 (CDK4/6), which promote cell cycle progression, and is used in combination with an aromatase inhibitor. For premenopausal and perimenopausal women, and for men, an LHRH agonist is added, with a 21-day on/7-day off schedule for a maximum of 3 years. Initially approved in the EU on August 22, 2017, for advanced or metastatic breast cancer, its expansion to the early-stage setting has structurally broadened the potential patient base.

NATALEE Phase 3 Supports Recurrence-Free Survival

The approval is based on the NATALEE trial (NCT03701334), a phase 3 open-label study in 20 countries involving 5,101 patients, randomized to receive ribociclib plus a non-steroidal aromatase inhibitor or endocrine therapy alone. The combination arm reduced the risk of invasive disease-free survival (iDFS) events by 25.1%, with a hazard ratio of 0.749, a 95% confidence interval of 0.628 to 0.892, and a p-value of 0.0006. EMA summary data showed an iDFS of approximately 91% versus 88% after 3 years of treatment. The inclusion of both node-positive patients and some node-negative patients with high tumor size, grade, and genomic risk has provided a broader EU label compared to competitors.

Regulatory History and Competitive Landscape

The European Medicines Agency (EMA) Committee for Medicinal Products for Human Use (CHMP) adopted a positive opinion on the label expansion on October 17, 2024, which was then ratified by the EC. The U.S. FDA also approved the combination of ribociclib and an aromatase inhibitor as adjuvant therapy for high-risk, early-stage (stage 2 or 3) adult patients on September 17, 2024. The main competitor is Eli Lilly's (LLY) Verzenio (abemaciclib), another CDK4/6 inhibitor, which is a standard option in combination with endocrine therapy for high-risk, node-positive early breast cancer. Pfizer's (PFE) Ibrance (palbociclib) failed to meet the efficacy goals in the PALLAS and PENELOPE-B phase 3 trials for adjuvant therapy in early breast cancer and has withdrawn from this market's approval competition.

Market Restructuring Reflected in Sales

In 2025, Kisqali sales are projected to reach $4.783 billion, an increase of 58%, while Verzenio is expected to generate $5.723 billion, and Ibrance $4.122 billion. The combined sales of these three products, totaling $14.628 billion, represent a performance-based indicator of the commercial market size of the CDK4/6 class. Kisqali has captured 63% of new prescriptions for early breast cancer in the U.S., and 82% and 73% in Germany and the UK, respectively, demonstrating prescription conversion following approval. However, EU approval does not automatically guarantee national reimbursement, so the speed at which the initial adoption observed in Germany and the UK can be extended to France, Italy, and Spain will be the next variable in European sales growth.