Two targeted therapies have become available to reduce the risk of recurrence in Australian patients with breast cancer and to delay disease progression in non-metastatic hormone-sensitive prostate cancer with biochemical recurrence.
Ribociclib in early breast cancer
The CDK4/6 inhibitor ribociclib (Kisqali, Novartis Australia) has now been TGA registered, in combination with a non-steroidal aromatase inhibitor (NSAI), for the adjuvant treatment of patients with HR+/HER2- stage II and III early breast cancer at high risk of recurrence including those with high-risk node-negative disease.
Ribociclib has previously only been available for the management of patients with HR+/HER2- advanced or metastatic breast cancer.
The TGA registration for ribociclib in early breast cancer is underpinned by results from NATALEE clinical trial, previously reported in the limbic [link here].
An interim analysis of the study found three years of treatment with ribociclib plus a NSAI, compared with a NSAI alone, significantly improved invasive disease–free survival among patients with HR+/HER2- stage II or III early breast cancer including node-negative or node-positive disease.
More recent four-year trial data from NATALEE was presented at the ESMO Congress in September 2024, demonstrating that ribociclib combined with a NSAI, reduced the risk of breast cancer recurrence by 28.5% compared to a NSAI alone.
“Based on the NATALEE trial results, the NCCN Guidelines were recently updated to recommend Kisqali®, in combination with an AI, as a Category 1 preferred CDK4/6 inhibitor for adjuvant treatment of patients with HR+/HER2- EBC, including those with high-risk, node-negative disease,” a statement from Novartis said.
Enzalutamide in prostate cancer
Meanwhile, the androgen receptor signalling inhibitor enzalutamide (Xtandi, Astellas Australia) is now available for patients with non-metastatic hormone-sensitive prostate cancer (nmHSPC) with biochemical recurrence at high-risk for metastasis.
The expanded indication, which provides earlier access to enzalutamide for Australian men, is based on results from the phase 3 EMBARK trial.
The trial, published in the NEJM in 2023 [link here], found that enzalutamide, both in combination with leuprolide and as monotherapy, significantly improved metastasis-free survival in men with high-risk biochemical recurrence of prostate cancer, compared to leuprolide alone.
High-risk biochemical recurrence was defined as a PSA doubling time of ≤9 months.
It found that at 5 years, metastasis-free survival was 87.3% in the enzalutamide plus leuprolide group, 80.0% in the enzalutamide monotherapy group and 71.4% in the leuprolide alone group.
“The risk of metastasis or death was 57.6% lower in the combination group than in the leuprolide-alone group, a difference that was significant (hazard ratio, 0.42; 95% CI, 0.30 to 0.61; P<0.001),” the study said.
Treatment with enzalutamide in combination or as monotherapy also resulted in a longer time to distant metastasis, symptomatic progression, and first symptomatic skeletal event.