The US Food and Drug Administration (FDA) granted Breakthrough Therapy designation to ribociclib, a CDK4/6 inhibitor, in combination with endocrine therapy for patients with hormone receptor–positive, HER2-negative advanced or metastatic breast cancer, according to a press release.1 The treatment combination was evaluated in both pre- and post-menopausal women.

Breakthrough Therapy designation was granted based on results from the randomized phase 3 MONALEESA-7 trial (ClinicalTrials.gov Identifier: NCT02278120), for which researchers compared the safety and efficacy of ribociclib plus endocrine therapy with endocrine therapy alone among 672 women with breast cancer previously untreated with endocrine therapy. Enrolled patients were between 25 and 58 years old; all patients also received goserelin.

The median progression-free survival (PFS) was 23.8 months (95% CI, 19.2-not reached) in the experimental group vs 13 months (95% CI, 11-16.4) in the endocrine therapy–only group (hazard ratio, 0.553; P < .0001). PFS benefit was seen in all subgroups regardless of variety of endocrine therapy.

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Adverse events were similar to those noted in previous trials: 3.6% of patients in the ribociclib group discontinued therapy because of toxicity vs 3% of patients in the endocrine therapy group. Neutropenia and leukopenia were, however, more common in the ribociclib group, occurring among 60.6% and 14.3% of patients, respectively; these adverse events were noted in less than 5% of patients in the endocrine therapy group.

This is the second Breakthrough Therapy designation for ribociclib; the first was granted in August 2016 after favorable results from MONALEESA-2. Breakthrough Therapy designation is reserved for new treatments likely to improve outcomes in a particular patient group.

Reference

  1. Novartis Kisqali® received FDA Breakthrough Therapy designation for initial endocrine-based treatment in premenopausal women with HR+/HER2- advanced breast cancer [news release]. Basel, Switzerland: Novartis; January 3, 2018. https://www.novartis.com/news/media-releases/novartis-kisqalir-received-fda-breakthrough-therapy-designation-initial-endocrine-based-treatment-premenopausal-women-hrher2-advanced-breast-cancer. Accessed January 4, 2018.