Young women undergoing standard hormone therapy for breast cancer had better chances of survival when given a newer drug in addition to their current treatment.
Researchers from the M.D. Anderson Cancer Center in Houston, Texas said Novartis' Kisqali (ribociclib) has shown an ability to retard the progression of cancer in patients who are already receiving hormone treatment for the disease.
Results from the drugmaker's MONALEESA-7 Phase III clinical trial revealed that when Kisqali was used in conjunction with endocrine therapy, it increased the survival rates of women with breast cancer by as much as 70.2 percent three-and-a-half years after the start of treatment.
By comparison, hormone therapy alone only increased the survival rate of cancer patients by 46 percent.
Dr. Debu Tripathy, chairman of the breast medical oncology department at M.D. Anderson and one of the authors of the study, said their work presents the first evidence that Kisqali can extend the lives of breast cancer sufferers.
He explained that the proof of survival advantage that they observed serves as "a pretty big milestone", and the findings argue for offering Kisqali as a "first-line or second-line" treatment for cancer patients.
The results of the MONALEESA-7 clinical trial will be presented at the annual meeting of the American Society of Clinical Oncology in Chicago on Tuesday, June 4. They will also be featured at the upcoming edition of the New England Journal of Medicine.
Novartis' Kisqali For Breast Cancer Treatment
Kisqali is one of three newly developed drugs known as CDK4/6 inhibitors that are now being offered in the market. The other two drugs are Ibrance (palbociclib) and Verzenio (abemaciclib). These medicines are designed to block the production of proteins that help cancer cells divide and grow in the body.
Novartis' drug was given approval as a tablet to be used as a first-line treatment for postmenopausal women suffering from an advanced stage of breast cancer that is hormone receptor-positive. This phase of the malignancy makes use of the patients' estrogen to fuel the growth of cancer cells. Most forms of breast cancers are under this category.
In 2018, U.S. Food and Drug Administration gave its approval for Kisqali to be used for younger, premenopausal women as well. The decision was based on initial findings of Novartis' clinical trial, where Kisqali was shown to lengthen the period that breast cancer patients remained progression-free, from one year to two years.
Questions Surrounding The MONALEESA-7 Results
Dr. Larry Norton, a breast cancer expert at the Memorial Sloan Kettering Cancer Center in New York, called the latest results of the MONALEESA-7 study "exciting".
Norton, who was not involved in the ongoing clinical trial, said he expects that it will be difficult for doctors not to include the drug in the standard of care, given the data from the Novartis study.
However, he also pointed out that the findings help raise "a lot of interesting questions".
For one, Norton asked whether the results were an effect of the drug or a drug-class effect. He also wondered if the other two CDK4/6 inhibitor drugs could produce similar benefits to breast cancer patients as Kisqali.
Tripathy said they do not know the answer to those questions yet. While all three CDK4/6 inhibitors have shown some biochemical differences between them, he noted that the drugs have been able to roughly double the time that cancer patients remained progression-free.
Another question Norton had was whether a patient already undergoing Kisqali treatment could benefit from another CDK4/6 inhibitor if her breast cancer were to progress.
Tripathy said they do not have the answer to that question as well. However, he believes some doctors might try out that strategy in a "real world" setting.
The latest results of the Kisqali clinical trial involved 672 female breast cancer patients, between the ages of 25 to 58, who were already in their premenopausal or menopausal stage.
All of the women were diagnosed with cancer that was hormone receptor-positive. However, they were negative for a protein called HER2.
The participants were given standard hormonal therapy, made up of either aromatase inhibitor or tamoxifen, and medication that blocks the estrogen production in their ovaries.
Half of the patients were given Kisqali, while the rest were given inactive placebo tablets. The participants took the CDK4/6 inhibitor in cycles of three weeks and one week off of the drug.
Compared to regular chemotherapy, Kisqali is considered "relatively non-toxic," according to Norton.
Potential Side Effects Of Taking Kisqali
Some of the possible side effects of the drug include constipation, diarrhea, fatigue, and nausea. Patients might also experience a drop in their white blood cells that can help keep them from infections.
Several of the women went on to develop QT prolongation. This is a condition that causes the electrical activity of the heart to change, leaving patients vulnerable to abnormal heart rhythms.
As a precaution, Novartis recommends patients should have their heart activity measured before and during Kisqali treatment.