A new international clinical trial (PALOMA-3) has yielded positive data for the treatment of breast cancer using Pfizer’s Ibrance (palbociclib) in combination with hormone therapy, fulvestrant.
Led by London-based Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust, the trial involved 521 advanced, hormone-sensitive, HER2- breast cancer patients at 144 research centres across 17 countries.
Data showed numerical improvement of nearly seven months in overall survival with palbociclib plus fulvestran, compared to placebo in combination with fulvestrant.
ICR said that the investigational drug’s benefit was better in women who had previously responded well to hormone therapy. These patients lived ten months longer with the combination treatment.
Ibrance is an oral, inhibitor of CDKs 4 and 6 that are known to be key regulators of the cell cycle triggering cellular progression. PALOMA-3 assessed the use of adding the drug to the hormone therapy.
It was observed that three years after enrolment, 49.6% of patients treated with the palbociclib combination were still alive, compared with 40.8% of women who were given only fulvestrant.
The palbociclib arm is also reported to have experienced a longer delay of 17.6 months until the start of chemotherapy, compared to 8.8 months with fulvestrant alone.
ICR molecular oncology professor Nicholas Turner said: “Delaying the need for chemotherapy is a central goal of treatment for women with this disease. This new data from PALOMA-3 show that adding IBRANCE to fulvestrant led to a substantial improvement in this important area.
“The difference in overall survival and prolonged time to chemotherapy demonstrated in PALOMA-3 further support the role of Ibrance in combination with endocrine therapy as a standard of care in HR+, HER2- metastatic breast cancer.”
The most common adverse reactions observed during the PALOMA-3 trial included neutropenia, leukopenia, infections, fatigue and nausea. Longer follow-up did not reveal any new safety signals.
UK National Institute for Health and Care Excellence (NICE) recommended Pfizer’s palbociclib for the treatment of breast cancer in November last year.
In December, the drug obtained the US Food and Drug Administration (FDA) priority review for its supplemental new drug application seeking approval for metastatic breast cancer.