Ribociclib Plus Oral Endocrine Partner Shows Efficacy in Women With HR+/HER2- Breast Cancer

Ribociclib (Kisqali) combined with an endocrine therapy and goserelin significantly prolonged progression-free survival (PFS) in women with hormone-receptor positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) advanced breast cancer, announced Novartis in a press release.

The MONALEESA-7 trial evaluated ribociclib in combination with oral endocrine therapy (tamoxifen or an aromatase inhibitor) and goserelin versus endocrine therapy and goserelin alone in premenopausal women with HR+/HER2- advanced breast cancer.

Phase III MONALEESA-7 trial results showed that the combination of ribociclib with either tamoxifen or an aromatase inhibitor and goserelin yielded significantly longer PFS when compared with endocrine therapy and goserelin alone. The combination provided a median PFS of 23.8 months (95% Cl, 19.2 months-not reached) compared with 13 months (95% Cl, 11.0-16.4 months) for tamoxifen or an aromatase inhibitor plus goserelin (hazard ratio [HR], 0.553; 95% CI, 0.441-0.694; P <.0001).

“The strength of MONALEESA-7 data is impressive and will give oncologists an important option if ribociclib is approved as treatment for this patient population as well as greater flexibility in the choice of endocrine therapy given with this agent,” said Debu Tripathy, MD, chair of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, in the statement. “Women who are premenopausal at the time of their breast cancer diagnosis tend to have more aggressive disease with poorer prognosis along with unique needs and experiences, so it is critical we determine which treatments will be most effective while also well tolerated.”

Ribociclib is the first CDK4/6 inhibitor to show efficacy in combination with tamoxifen when assessed against the endocrine therapy alone (median PFS of 22.1 vs 11.0 months; HR, 0.585; 95% Cl, 0.387-0.884). The combination of ribociclib and an aromatase inhibitor produced an additional 14 months of PFS over the endocrine therapy alone (median PFS of 27.5 vs 13.8 months; HR, 0.569; 95% Cl, 0.436-0.743).

Trial results also showed that premenopausal women being administered ribociclib benefited for a longer period of time without health-related quality of life deterioration compared with those being administered endocrine therapy alone. In addition, women taking ribociclib saw a significant improvement in pain symptoms as early at 8 weeks.

“We are pleased to see Kisqali combination therapy provide strong efficacy and prolonged quality of life with pain reduction in younger women, and look forward to working with health authorities to bring a new treatment options to premenopausal and perimenopausal women,” said Samit Hirawat, MD, head of Novartis Oncology Global Drug Development, in the statement.

Back in March, ribociclib was approved as a front-line therapy for postmenopausal women with HR+/HER2- advanced or metastatic breast cancer. The FDA approval followed the MONALEESA-2 trial results showing that ribociclib plus letrozole, an aromatase inhibitor, reduced the risk of progression or death by 44% compared with letrozole alone.