Palbociclib has been approved by the US FDA since 2015 yet safety and efficacy data among Asian patients is limited. This study reports the use of this drug in ER-positive HER2-negative MBC in Hong Kong as real world practice.
The demographic data, treatment response, and toxicity profile of patients received palbociclib were collected in a prospectively maintained database. Patients were from both the public and private sectors. The study is supported by the Hong Kong Breast Cancer Foundation.
Fifty-four patients who have received palbociclib for the first time were recruited in the database. The median age was 51 year (range 34-81) and all patients were ethnic Chinese. All were post-menopausal by natural state (67%) or by ovarian suppression. Over half (55%) obtained palbociclib from the name-patient program prior to the launch of the drug in Hong Kong in Jan 2017. The proportion of first line use was 30% prior to- and 36% after the official launch of palbociclib. The partner endocrine therapy (ET) was aromatase inhibitor (39% letrozole, 11% exemestane) or fulvestrant (50%). Except for 4 patients, the majority (93%) were started on the standard dose of 125 mg/day. Of those started on 125 mg/day, 43% developed Gd 3 neutropenia, and 7% had Gd 4 neutropenia during the first cycle; 31% had dose reduction to 100 mg/day on second cycle. Other adverse events (AEs) included anemia (4%), thrombocytopenia (9%), stomatitis (5%), hand-foot syndrome (4%), fatigue (4%), and low appetite (4%). All these were Gd 1-2. No patient had neutropenic fever. Response assessment was available in 37 cases. The disease control rate was 70%. Many responded patients had visceral disease (54%) and were heavily pretreated (chemotherapy 1 line 15%, > =2 lines 35%; ET > =2 lines 27%; mTOR inhibitor 12%).
This is the first real world data reporting the preliminary efficacy and AEs of palbociclib among ER-positive HER2-negative MBC patients from Hong Kong. Palbociclib was well tolerated. The experience is consistent with published literature of Palbociclib. The use of palbociclib in Hong Kong is often in the second or later line setting and the cause remains to be elucidated.
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All authors have declared no conflicts of interest.