Ribociclib plus endocrine therapy in early stage breast cancer
- A new study shows that the drug, Ribociclib plus endocrine therapy improves survival and slows cancer growth for at least three years in patients with hormone receptor positive, HER2 negative early stage breast cancer.
- 90.4% of the patients on Ribociclib plus endocrine therapy were disease free at three years compared to 87.1% of patients who received endocrine therapy alone.
- People treated with both drugs also had a 90.4% chance of halting cancer spread, versus 87.1% with only the endocrine treatment.
- Doctors may recommend Ribociclib as a starting treatment option for metastatic breast cancer that is metastatic, meaning it has spread, and is also hormone positive, HER2 negative, a type of breast cancer that grows in response to hormones like estrogen and progesterone but does not have an excess of the HER2 protein, which can promote cancer growth.
The therapy combines the drug ribociclib with an a nonsteroidal aromatase inhibitor (NSAI) endocrine therapy.
Read MoreRelated: An Overview of Breast Cancer Treatment
What is Ribociclib?
Ribociclib belongs to a class of medications known as kinase inhibitors which block the actions of kinase, a type of protein in cells that play a key role in growth, metabolism, and cell repair. Inhibiting kinase in cancer cells slows down the cancer from growing and spreading.
Ribociclib is usually taken once daily in pill form along with the NSAI hormone therapy.
Doctors determine what type of cancer a patient has before treatment with a test called a biopsy. This involves removing a small sample of the tumor for testing in the lab.
If a patient’s disease is metastatic, hormone receptor positive, HER2 negative, then the combination therapy can be considered as a first-line treatment, meaning it is is the first treatment doctors will use.
What are the benefits of this treatment?
The phase 3 NATALEE clinical trial followed more than 5,000 patients with metastatic, hormone receptor positive, HER2 negative breast cancer who received either ribociclib plus NSAI or NSAI alone. Ribociclib was given for 3 weeks followed by 1 week off for a total of 3 years. The endocrine therapy was given once daily for at least 3 years.
The results at three years showed:
- Combined treatment stopped the cancer from coming back in 91.7% of cases, better than the 88.6% with the NSAI alone
- People treated with both drugs had a 90.4% chance of halting cancer spread, versus 87.1% with only the NSAI treatment.
- The chance of cancer not spreading far was 90.8% with the combined treatment versus 88.6% with NSAI treatment alone.
The study also showed that when using the combined therapy, patients had less of a chance their disease would return or spread to other parts of the body. Additionally the combination of these medications did not produce any new or unexpected side effects.
Related: Hormone Therapy for Breast Cancer
What are the possible side effects?
The combo of Ribociclib plus NSAI is generally well tolerated by patients. However, like any treatment it may cause side effects including:
- Nausea
- Fatigue
- Headache
- Diarrhea.
More serious side effects may include:
- Changes in heart rhythm
- Severe infections
- Liver problems
- Blood clots.
“We were attempting to improve tolerability while maintaining efficacy, based on the observation that efficacy was maintained in patients with metastatic disease on lower doses of CDK4/6 inhibitors. -NATALEE is the only adjuvant study that treated patients for 3 years [with a CDK4/6 inhibitor] rather than 2 years,” Dr. Slamon noted.
Patients should promptly report any unusual symptoms or side effects to their healthcare provider for proper evaluation and management.
What is the current standard of care?
Currently, Ribociclib is not included in the standard of care for treatment of early stage breast cancers. Dr. Slamon hopes the new study results may change that.
“Overall, the NATALEE trial supports support ribociclib plus endocrine therapy as a new treatment option for a much larger population of patients with HR-positive, HER2-negative early breast cancer,” said Slamon. “These findings should change how we evaluate and treat patients.”
As of now, treatment can vary depending on a variety of factors including patient age, cancer size, lymph node involvement, cancer receptor type, and genetic testing of the cancer among other things.
Treatment usually includes:
- Surgery: Doctors will usually consider some sort of surgery for patients with a breast cancer diagnosis. They may recommend a lumpectomy where a portion of the breast tissue is removed, or a mastectomy where all of the breast tissue is removed. Lymph nodes from the armpit (axilla) are sometimes also removed and tested for cancer.
- Chemotherapy: This treatment is often used before or after surgery. The type and length of chemotherapy depends on a variety of factors.
- Radiation: This involves a high powered x-ray, and is sometimes used after surgery (and chemotherapy if needed). It can be delivered to the breast and armpit or breast alone with treatment times varying from a week to several weeks in length.
- Endocrine therapy: This treatment often starts after all other treatment are completed. It is given as a pill form taken once daily for at least 5 years in cases of HR-positive breast cancers to reduce the risk of recurrence.
Questions for your doctor
- What are the potential benefits of this treatment for my specific condition?
- What are the possible side effects and how can they be managed?
- How will this treatment fit into my overall care plan?
- How often will I need to be monitored during treatment?
- Are there any alternative treatments or clinical trials I should consider?
- How much of my treatment is covered by insurance and how much can I expect to pay out of pocket?
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