FDA also approved ribociclib and the aromatase inhibitor letrozole packaged together (Kisqali Femara Co-Pack, Novartis) for the same indication.
A rival cyclin-dependent kinase 4/6 (CDK4/6) inhibitor abemaciclib (Verzenio, Eli Lilly) carries a similar adjuvant indication, but use of this agent requires patients to be lymph node–positive.
There’s no such restriction for the new ribociclib indication, which “allows us to offer treatment with a CDK4/6 inhibitor to a significantly broader group of people,” lead investigator Dennis J. Slamon, MD, breast oncologist at the University of California Los Angeless, said in a Novartis press release.
The new indication joins ribociclib’s previous approval for advanced or metastatic HR-positive, HER2-negative breast cancer in combination with an aromatase inhibitor or fulvestrant.
The current approval was based on data from the NATALEE trial. NATALEE randomized 5101 patients with early-stage HR-positive, HER2-negative disease to either 400 mg ribociclib with an aromatase inhibitor or to an aromatase inhibitor alone following surgery.
Invasive disease-free survival at 36 months was 90.7% in the ribociclib arm vs 87.6% with aromatase inhibitor monotherapy (hazard ratio [HR], 0.749; P = .0006). The trial included patients with and without lymph node involvement.
At 4 years (well beyond NATALEE’s 3-year treatment window), the ribociclib group continued to do better, with an invasive disease-free survival rate of 88.5% vs 83.6% in the control arm.
Overall survival data remain immature but with a trend towards improved survival in the ribociclib arm (HR, 0.715; P < .0001), according to a recent report from the 2024 European Society for Medical Oncology Congress.
There were no new safety signals in the trial. Adverse events in the ribociclib group included neutropenia (62.5% overall; 44.3% grade 3/4), liver-related events (26.4% overall; 8.6% grade 3/4), QT prolongation (5.3% overall; 1.0% grade 3/4), and interstitial lung disease/pneumonitis (1.5% overall; 0.0% grade 3/4), according to Novartis.
Ribociclib dosing for the adjuvant indication is lower than for metastatic disease, but patients are on the same schedule — two 200 mg tablets once daily for 21 days followed by 7 days off in 28-day cycles. Treatment continues for 3 years.
Forty-two 200 mg tablets cost about $15,000, according to drugs.com. A patient assistance program is available through Novartis.
A version of this article appeared on Medscape.com.