Novartis' CDK 4/6 inhibitor ribociclib hits main goal of pivotal breast cancer study

Novartis announced Wednesday that a Phase III trial of ribociclib in patients with breast cancer was stopped early on the recommendation of an independent Data Monitoring Committee after a pre-planned interim analysis showed that the trial met its primary endpoint of a clinically meaningful improvement in progression-free survival (PFS). The company noted that based on the results it will begin discussions with global regulators about marketing application for the CDK 4/6 inhibitor.

The MONALEESA-2 study randomised 668 postmenopausal women who had received no prior therapy for their hormone receptor positive, HER2-negative advanced breast cancer to receive either ribociclib, also known as LEE011, or placebo, in combination with Novartis' Femara (letrozole). Along with the trial's main goal of PFS, secondary endpoints include overall survival, overall response rate, clinical benefit rate, health-related quality of life, safety and tolerability.

According to Novartis, adverse events observed with ribociclib in the study were generally consistent with the drug's known adverse event profile. The company indicated that the trial will continue to assess overall survival data, with detailed results planned to be presented at a future medical meeting.

"We are excited that these results validate our belief that LEE011 in combination with [Femara] can be a beneficial treatment option for women diagnosed with HR+/HER2- advanced breast cancer," remarked Alessandro Riva, global head of oncology development and medical affairs in Novartis' oncology unit. Ribociclib was developed by the Novartis Institutes for BioMedical Research as part of a research collaboration with Astex Pharmaceuticals.

Last year, Pfizer's Ibrance (palbociclib) became the first CDK 4/6 approved by the FDA, in combination with Femara, for the treatment of postmenopausal women with oestrogen receptor-positive, HER2-negative metastatic breast cancer. Earlier this month, Pfizer reported that first-quarter sales of the drug reached $429 million, beating estimates of $393 million.

For related analysis, see Physician Views: Taking the pulse of Pfizer's Ibrance in breast cancer, and Spotlight On Interview: Playing with the big boys – FirstWord discusses the future CDK 4/6 inhibitor market with G1 Therapeutics CEO Mark Velleca.

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