IBRANCE (palbociclib) is an oral formulation that treats metastatic breast cancers that have maintained disease progression post endocrine therapy.
Breast cancer is the carcinoma of the breast tissue, either ductal or lobular. In ductal carcinomas, the tubes of the breast that carry milk to the nipple are affected. For lobular carcinoma, the lobules in the breast that produce milk are affected.
Metastatic breast cancer means that the tumours have spread beyond the lymph nodes.
IBRANCE is a cyclin-dependent kinases 4 and 6 (CDK 4/6) inhibitor. The drug targets the CDK 4/6 pathway, inhibiting the growth and proliferation of tumour cells. IBRANCE also works to stop tumour cells from progressing beyond the G1 phase of tumour progression.
In February 2015, IBRANCE was approved to be used as a treatment in HR+ and HER2- metastatic breast cancer when combined with Letrozole. In this instance, IBRANCE was to be used as an initial endocrine-based therapy.
In February 2016, IBRANCE was first approved by the US Food and Drug Administration (FDA) to be used as a treatment in hormone receptor-positive (HR+) metastatic breast cancer when combined with Fulvestrant. IBRANCE was also approved for treatment in human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer when combined with Fulvestrant.
IBRANCE was the first cyclin-dependent kinase inhibitor approved by the FDA. It will also be the first to be approved by the European Commission.
The FDA approval of IBRANCE came as a result of a phase III clinical trial called PALOMA-3. Patients who received IBRANCE combined with Fulvestrant showed progression-free survival (PFS) at a median of 9.5 months. This was compared to patients who did not receive IBRANCE combined with Fulvestrant (instead, they received a placebo).
Some of the adverse reactions that were observed during the trial included pulmonary embolism, neutropenia, fatigue, embryo-fetal toxicity, anaemia, nausea, rash, leukopenia, pyrexia and a decreased appetite.
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