Ribociclib (Kisqali) is already used to treat advanced hormone receptor-positive (HR-positive) breast cancer. Now new research has shown it can also reduce the risk of recurrence when used in early breast cancer. 

Ribociclib is known to improve survival when given to people with advanced HR-positive breast cancer. It belongs to a group of medicines called CDK 4/6 inhibitors; palbociclib (Ibrance, which is funded in New Zealand) and abemaciclib (Verzenio) are others in this group. 

New research has now shown that ribociclib can significantly reduce the risk of recurrence when added to endocrine therapy for early HR-positive, HER2-negative breast cancer. This discovery could improve treatment for many people, given that around two thirds of breast cancers are HR-positive. 

Currently endocrine therapy, using anti-oestrogen medicines such as tamoxifen or an aromatase inhibitor (anastrozole, exemestane or letrozole), is given as a multi-year treatment after surgery and chemo in these patients to prevent recurrence of their breast cancer. However, around a third of those diagnosed with stage 2 disease and half with stage 3 will experience a recurrence.

In the NATALEE clinical trial, over 5,000 people (pre- and post-menopausal women and men) with Stage 2 or 3 HR-positive breast cancer were randomly assigned to two groups. Everyone received 5 years of endocrine therapy, but one group was also given ribociclib for 3 years. After follow-up at 34 months, 90.4% of those given ribociclib were still free of invasive disease compared to 87.1% of those who received only the endocrine therapy. This difference is statistically significant, indicating that ribociclib can reduce the risk of recurrence in people with this subtype of breast cancer.  Follow-up will continue and more results will published in future.

These results were presented this month at the ASCO 2023 cancer research conference in the United States. Click here to read more about this trial. 

In New Zealand, ribociclib was registered in 2019 with Medsafe for first-line and later-line use in patients with advanced HR-positive HER2-negative breast cancer. Manufacturer Novartis applied to Pharmac for it to be publicly funded for these patients in April 2019 (first-line) and February 2020 (later line). In June 2023 Pharmac was still assessing these applications.

BCAC Chair Libby Burgess comments “It’s great to see evidence that ribociclib can help to prevent recurrence in early breast cancer. We hope to see applications soon for Medsafe approval and Pharmac funding so New Zealanders with early HR-positive HER2-negative breast cancer can benefit from ribociclib”.

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