The FDA ( U.S. Food and Drug Administration ) has extended the indication of Ibrance ( Palbociclib ) capsules in combination with specific endocrine therapies for hormone receptor-positive ( HR+ ), human epidermal growth factor receptor 2-negative ( HER2- ) advanced or metastatic breast cancer in male patients.
Breast cancer is rare in males with only 2,670 cases of male breast cancer estimated in 2019, less than 1% of all cases of breast cancer.
The majority of breast tumors in male patients express hormone receptors.
Men are more likely to be diagnosed at an older age, with a more advanced stage of disease. Metastatic breast cancer is breast cancer that has spread beyond the breast to other organs in the body ( most often the bones, lungs, liver or brain ).
When breast cancer is hormone-receptor positive, patients may be treated with hormone therapy ( endocrine therapy ) or chemotherapy.
Endocrine therapy slows or stops the growth of hormone-sensitive tumors by blocking the body’s ability to produce hormones or by interfering with effects of hormones on breast cancer cells. There are several FDA-approved endocrine based therapies available for HR-positive metastatic breast cancer patients. Certain treatments are gender-neutral in their indication, but some therapies have been approved only for women, although they are often prescribed for male patients. According to the current clinical practice standards, male patients with breast cancer are treated similarly to women with breast cancer.
Ibrance was initially approved in 2015. It is a kinase inhibitor, approved in combination with an aromatase inhibitor as the first hormonal-based therapy in women who have gone through menopause and in men, or with Fulvestrant in patients whose disease progressed following hormonal therapy.
Pfizer provided the results of an analysis of real-world data ( RWD ) from electronic health records ( EHRs ) as additional supportive data to characterize the use of Palbociclib in combination with endocrine therapy ( aromatase inhibitor or Fulvestrant ) in male patients with breast cancer based on observed tumor responses in this rare subset of patients with breast cancer.
The most common side effects of patients taking Ibrance are infections, leukopenia ( low levels of white blood cells ), fatigue, nausea, stomatitis ( inflammation of the mouth and lips ), anemia ( low levels of red blood cells ), hair loss, diarrhea and thrombocytopenia ( low levels of thrombocytes, also known as platelets, in the blood ).
Other common side effects reported are rash, vomiting, decreased appetite, asthenia ( abnormal physical weakness or lack of energy ) and fever.
Health care providers are advised to monitor a patient’s blood count for neutropenia ( low levels of white blood cells called neutrophils ).
Patients should have their blood count checked prior to starting Ibrance and at the beginning of each cycle, as well as on day 15 of the first two cycles and as clinically indicated.
Because of the potential for genotoxicity, health care providers are advised to tell male patients with female partners of reproductive potential to use effective contraception during treatment with Ibrance and for three months after the last dose.
Women who are pregnant or breastfeeding should not take Ibrance because it may cause harm to a developing fetus or newborn baby. ( Xagena )
Source: FDA, 2019