FDA Expands Use of Breast Cancer Drug to Men
The US Food and Drug Administration (FDA) has extended the indication of the breast cancer drug palbociclib (Ibrance, Pfizer) to include male patients.
Palbociclib capsules are used in combination with specific endocrine therapies for hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced or metastatic breast cancer. The drug was initially approved in 2015.
The indication was expanded on the basis of data from postmarketing reports and electronic health records that show that the safety profile for men treated with palbociclib is "consistent with" the safety profile for women, said Richard Pazdur, MD, acting director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research in a press statement.
Pazdur added that "some approved indications for breast cancer treatments do not distinguish by gender, but in certain cases, if there is a concern that there may be a difference in efficacy or safety results between men and women, then further data may be necessary to support a labeling indication for male patients."
Breast cancer is rare in males. It is estimated that only 2670 cases will occur in 2019, which is fewer than 1% of all cases of breast cancer, said the FDA. However, the majority of breast tumors in male patients express hormone receptors; such tumors are typically treated with endocrine-based therapies, which, in advanced cancers, may include palbociclib.
The FDA pointed out that although some breast cancer therapies have been approved only for women, these drugs are often prescribed for male patients too, and that in general, males are treated similarly to women, per clinical practice standards.
The most common side effects of palbociclib are infections, leukopenia, fatigue, nausea, stomatitis, anemia, hair loss, diarrhea, and thrombocytopenia. Other common side effects include rash, vomiting, decreased appetite, asthenia, and fever.
Healthcare providers should monitor patients for neutropenia. Such monitoring should be undertaken before the start of therapy, at the beginning of each cycle, and on day 15 of the first two cycles.
Use of palbociclib is associated with a risk for genotoxicity. Male patients with female partners of reproductive age should be warned of that risk and should use effective contraception during treatment and for 3 months after taking the last dose.
